Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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ENVIRONMENTALLY PREFERRED
FLUIDS AND FLUID BLENDS
Cross-Reference To Related Applications
This application is a continuation-in-part of U.S. Patent
Application, Serial Nos. 09/288,055, filed on April 7, 1999, and
09/305,548, filed on May 5, 1999, which are based on U.S. Provisional
Application Serial Nos. 60/084,347, filed May 5, 1998, and 60/087,150,
filed May 29, 1998.
Field Of The Invention
This invention relates to the selection and use of
environmentally preferred fluids and fluid blends which exhibit low or
reduced reactivity with respect to ozone formation. These
environmentally preferred fluids and fluid blends are useful in a number
of applications, particularly as industrial solvents, and allow formulators
an effective means to improve the environmental performance of their
formulations or products.
Background Of The Invention
Fluid applications are broad, varied, and complex, and each
application has its own set of characteristics and requirements. Proper
fluid selection and fluid blend development have a large impact on the
success of the operation in which the fluid is used. For instance, in a
typical industrial coatings operation, a blend of several fluids is used in
order to get an appropriate evaporation profile. Such a blend must also
provide the appropriate solvency properties, including formulation
stability, viscosity, flow/leveling, and the like. The fluid blend choice
also affects the properties of the dry film, such as gloss, adhesion, and
the like. Moreover, these and other properties may further vary
according to the application method ~e.g., spray-on), whether the
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substrate is original equipment (OEM), refinished, etc., and the nature
of the substrate coated.
Other operations involving the use of fluids and fluid blends
include cleaning, printing, delivery of agricultural insecticides and
pesticides, extraction processes, use in adhesives, sealants,
cosmetics, and drilling muds, and countless others. The term "fluid"
encompasses the traditional notion of a solvent, but the latter term no
longer adequately describes the possible function of a fluid or blend in
the countless possible operations. As used herein the term "fluid"
includes material that may function as one or more of a carrier, a
diluent, a surface tension modifier, dispersant, and the like, as well as a
material functioning as a solvent, in the traditional sense of a liquid
which solvates a substance (e.g., a solute).
The term "industrial solvent" applies to a class of liquid organic
compounds used on a large scale to perform one or more of the
numerous functions of a fluid in a variety of industries. Relatively few
of the large number of known organic compounds that could be used
as fluids find use as industrial solvents. Fluids that are used in large
quantities have heretofore been selected because they can be
produced economically and have attractive safety and use
characteristics in manufacturing, consumer and commercial
environments. Examples of commercial solvents and their uses as
industrial solvents are described in an article entitled "Solvenfs,
IndustriaP', by Don A. Sullivan, Shell Chemical, Encyclopedia of
Chemical Technology, 4th. ed., V. 22, pp. 529 - 571 (III) (1997).
In addition to the problems with fluid and fluid blend selection
mentioned at the outset, there is also the problem that, in most
applications, at least some of the fluid evaporates and can escape into
the environment. Although many industrial coating operations, such as
in original equipment manufacturing (OEM), utilize control equipment to
capture or incinerate >95% of the solvent emissions, nevertheless in a
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majority of applications some of the solvents inevitably enters the
atmosphere.
The United States Environmental Protection Agency (EPA) has
developed National Ambient Air Quality Standards (NAAQS) for six
pollutants: ozone, nitrogen oxides (NOX), lead, carbon monoxide, sulfur
dioxide and particulates. Of all the NAAQS standards, ozone non-
attainment has the greatest impact on solvent operations.
Solvents typically are volatile organic compounds (VOC), which
are involved in complex photochemical atmospheric reactions, along
with oxygen and nitrogen oxides (NOx) in the atmosphere under the
influence of sunlight, to produce ozone. Ozone formation is a problem
in the troposphere (low atmospheric or "ground-based"), particularly in
an urban environment, since it leads to the phenomenon of smog.
Since VOC emissions are a source of ozone formation, industrial
operations and plants using solvents are heavily regulated to attain
ozone compliance. As different regulations have been adopted, the
various approaches to controlling pollution have evolved. Certain early
regulations controlled solvent composition, while later regulations
primarily concerned overall VOC reduction.
According to current VOC emission regulations in the U.S.A.,
solvents generally belong to one of two groups depending on their
reactivity toward atmospheric photochemical ozone formation:
(a) Negligible reactivity organic compounds which generate about the
same or less quantity of ozone as would be produced by the same
weight % as ethane. These organic compounds are exempt from the
definition of a VOC and are not considered to be a VOC in any solvent
(fluid) composition. There are numerous such compounds exempted
by the EPA from the definition of VOC. However, a majority of such
exempted compounds are halogenated derivatives which can possess
one or more of the following deficiencies: toxicity, ozone depletion, or
waste disposal or incineration problems. Other non-halogenated,
oxygenated organic compounds, such as acetone and methyl acetate,
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have been exempted by the EPA, but such compounds have extremely
high evaporation rates and high flammability so as to reduce their
applicability in numerous applications. Other such organic compounds,
such as tertiary butyl acetate which is under exemption consideration
by the EPA, while having a significantly improved flammability level and
evaporation rate, may be too chemically and thermally unstable for
many applications.
(b) All other oxygenated and hydrocarbon solvents are considered to
be VOC's and treated by the EPA as equally (on a weight basis)
polluting.
A more recent U.S. regulation has combined VOC reduction with
composition constraints. While the traditional source of emission
reduction is large stationary industrial facilities, the EPA and other
governmental entities have turned increasingly to consumer and
commercial products for reduction in their solvent usage as an
additional means to lower VOC emission and therefore ozone
formation. Numerous government and trade publications discuss
VOC's, and information is readily available on the Internet. See, for
instance, http://www.paintcoatings.net/VOCW97.html.
Various measurements of reactivity with respect to ozone
formation are known. For instance, reactivity can be measured in
environmental smog chambers, or they may be calculated using
computer airshed models. See, for instance, Dr. William P. L. Carter,
"Uncertainties and Research Needs in Quantifying VOC Reactivity for
Stationary Source Emission Controls", presented at the California Air
Resources Board (CARB) Consumer Products Reactivity Subgroup
Meeting, Sacramento, CA (October 17, 1995).
There has also been developed a "K°" scale", which provides a
relative scale of the reactivity of VOC with the OH radicals involved in
the complex reactions that produce ozone. See, for instance, Picquet
et al., !nt. J. Chem. Kinet. 30, 839-847 (1998); Bilde et al., J. Phys.
Chem. A 101, 3514-3525 (1997).
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Numerous other reactivity scales are known and new reactivity
scales are constantly being developed. Since this is a rapidly
changing area of research, the most up-to-date information is often
obtained via the Internet. One example is Airsite, the Atmospheric
5 Chemistry International Research Site for Information and Technology
Exchange, sponsored by the University of North Carolina and the
University of Leeds, at http:llairsite.unc.edu.
Another way to measure the reactivity of a chemical in ozone
formation is by using a technique developed by Dr. Carter (supra) at
the Center for Environmental Research and Technology (CERT),
University of California at Riverside. The CERT technique measures
"incremental reactivities", the incremental amount of ozone that is
produced when the chemical is added to an already polluted
atmosphere.
Two experiments are conducted to measure the incremental
reactivity. A base case experiment measures the ozone produced in
an environmental smog chamber under atmospheric conditions
designed to represent a polluted atmosphere. The second experiment
called "the test case" adds the chemical to the "polluted" smog
chamber to determine how much more ozone is produced by the newly
added chemical. The results of these tests under certain conditions of
VOC and nitrogen oxide ratios are then used in mechanistic models to
determine the Maximum Incremental Reactivities (MIR), which is a
measure of ozone formation by the chemical compound in question.
The State of California has adopted a reactivity program for
alternative fuels based on this technique and the EPA has exempted
several compounds due to studies conducted by CERT. See, for
instance, Federal Register 31,633 (June 16, 1995) (acetone); 59
Federal Register 50,693 (Oct. 5, 1994) (methyl siloxanes), Federal
Register 17,331 (April 9, 1998) (methyl acetate). CARB and EPA have
uses a weight average MIR for regulatory purposes, wherein the weight
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average MIR of a solvent blend is calculated by summing the product
of the weight percent of each solvent and its respective MIR value.
A fist of compounds and their MIR values is available in the
Preliminary Report to California Air Resources Board, Contract No. 95-
308, William P.L. Carter, August 6, 1998. A table of known MIR values
may be found on the Internet at
http://helium.ucr.edu/~carter/index.html. CERT obtains other
incremental reactivities by varying the ratios of VOC and nitrogen
oxides. A detailed explanation of the methods employed and the
determination of incremental reactivities and MIR scale may be found
in the literature. See, for instance, International Journal of Chemical
Kinetics, 28, 497-530 (1996); Atmospheric Environment, 29, 2513-2527
(1995), and 29, 2499-2511 (1995); and Journal of the Air and Waste
Management Association, 44, 881-899 (1994); Environ. Sci. Technol.
23, 864 (1989). Moreover, various computer programs to assist in
calculating MIR values are available, such as the SAPRC97 model, at
http://helium.ucr.edu/~carter/saprc97.htm.
Any of these aforementioned scales could be used for regulatory
purposes, however the MIR scale has been~found to correlate best to
peak ozone formation in certain urban areas having high pollution, such
as the Los Angeles basin. MIR values can be reported as the absolute
MIR determined by the CERT method or as a relative MIR. One
common relative MIR scale uses the Reactive Organic Gas (ROG) in
the base case as a benchmark. The Absolute Reactivity ROG is 3.93 g
03 per gram ROG. This value is then .the divisor for the absolute MIR
of other VOCs, if MIR is cited relative to ROG. Absolute reactivities
related to the ROG with the above mentioned absolute reactivity 3.93
are provided in "Updated Maximum Incremental Reactivity Scale for
Regulatory Applications", Preliminary 'Report to California Air
Resources Board, Contract No. 95-308, William P. Carter, August 6,.
1998. For the purposes of this invention and specification, unless
otherwise specifically stated, all MIR values provided herein are
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Absolute MIR values. It is understood, however, that the Absolute MIR
values can be converted to Relative MIR and back to Absolute MIR by
division or multiplication of MIR by ROG.
Current regulations based on VOC emissions do not take into
consideration the wide difference in ozone formation among non-
exempt VOC compounds. For example, two non-exempt VOC
compounds can have dramatically different ozone formation
characteristics. Accordingly, current regulations do not encourage end
users to minimize ozone formation by using low reactivity solvent
compositions. Although there are federal and state regulatory trends
toward requiring the reduction of the reactivity of solvents, the number
of exempt solvents is small and in no way satisfies all the other
properties required for an effective solvent such as good solvency,
appropriate flash point, evaporation rate, ,boiling temperature, chemical
and thermal stability.
Solvents currently viewed as essentially non-ozone producing
are those which have reactivity rates in the range of ethane. Ethane
has a measured reactivity based on the MIR method of 0.35. In fact,
the EPA has granted a VOC exemption to certain solvents with
reactivity values in this range including acetone (MIR=0.48) and methyl
acetate (MIR=0.12).
However, the number of known materials having reactivities of
0.50 or less based on the MIR scale is relatively small. Moreover, it is
a discovery of the present inventors that many if not most of the known
fluids having acceptable reactivities with respect to ozone formation
have other unfavorable performance characteristics, e.g., poor solvent
properties, low flash point, inappropriate evaporation rate or volatility
characteristics, unacceptable toxicity, unacceptable particulate matter
formation, thermal or chemical instability and as such have limited, if
any, applicability in industry. For example, ethane is a gas under
ambient conditions and hence is a poor choice as an industrial solvent.
Methyl acetate has an excellent MIR=0.12, buff a low flash point of
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about -12°C; acetone has an acceptable MIR=0.48, but is extremely
flammable. As a further example, tertiary butyl acetate (t-butyl acetate)
has an excellent MIR=0.21, but has limited thermal stability and is
unstable to acid catalysts which may be present in an industrial
operation.
Regarding particulate matter, the EPA has recently proposed
standards for particulate matter under 2.5 pm (microns) in diameter
("PM2.5"). See 61 Federal Register 65638-65713 (December 13,
1996). The proposal sets an annual limit, spatially averaged across
designated air quality monitors, of 15 pg/m3, and a 24-hour standard of
65 pg/m3. Numerous discussions of this proposed standard are
available on the Internet, such as at http://www.cnie.org/nle/air~html,
which cites numerous references (such as Wolf, "The Scientific Basis
for a Particulate Matter Standard", Environmental Management
(October, 1996, 26-31 )). As far as the present inventors are aware, the
prior art has not addressed ways of meeting these proposed
requirements, much less in meeting these requirements in conjunction
with ozone reduction requirements.
Moreover, the present inventors have also discovered that in
many applications, VOC exempt solvents cannot be used as a one-for-
one replacement for conventional solvents. Rather the formulator must
balance a number of performance factors to develop an acceptable
solvent or solvent blend for a particular application. Some factors are
more relevant than others for specific applications. Nevertheless,
many performance factors are similar for a number of applications.
Numerous attempts have been made to utilize the concept of
"environmentally friendly" fluids in practical applications. For instance,
there are a number of cleaning and/or stripping formulations available
that are said to overcome certain prior art environmental problems.
Examples include a binary azeotrope of octamethyltrisiloxane with n-
propoxypropanol (U.S. Pat. No. 5,516,450), hexamethyldisiloxane and
azeotropes and other mixtures thereof (U.S. Pat. No. 5,773,403), a
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nonazeotropic mixture including a halocarbon and an oxygenated
organic solvent component having at least 3 carbons, which may be,
for instance, dimethylcarbonate (U.S. 5,552,080), and a composition
comprising an amide and a dialkyl carbonate (U.S. 4,680,133).
In addition, there have been a number of patents and literature
references to materials intended to replace chlorofluorocarbons (CFCs)
as, for instance, blowing agents. These efforts address stratospheric
ozone depletion, which is the opposite phenomenon addressed by the
present invention. Examples include the use of dimethoxymethane and
cyclopentane (U.S. 5,631,305; 5,665,788; and 5,723,509),
cyclopentane (U.S. 5,578,652) and polyglycols (U.S. Pat. No.
5,698,144). Still further, a "non-ozone depleting" solvent comprising
halogenated compounds and an aliphatic or aromatic hydrocarbon
compound having 6-20 carbon atoms is disclosed in U.S. Pat. No.
5,749,956. Similarly, U.S. Pat. No. 5,004,480 describes a method for
reducing the levels of air pollution resulting from the combustion of
diesel fuel in engines comprising blending dimethyl carbonate (DMC)
with diesel fuel and combusting the blended fuel in engines. U.S. Pat.
No. 5,032,144 also discusses the addition of oxygenates, including
methyl pivalate (methyl 1,1,1-trimethyl acetate) to gasoline (as octane
boosters). The problems addressed by these patents do not relate to
the problem of industrial solvent evaporation.
WO 98/42774 discloses solvent-resin compositions which "do
not contribute appreciably to the formation of ground based ozone".
Organic solvents are selected based upon having "reaction rates with
hydroxyl ion slower than ethane", and generally selected from
halogenated solvents such as chlorobromomethane, methyl chloride,
and the like. The only non-halogenated solvents that are suggested
are n-alkanes (C~2 - C~8), methyl and t-butyl acetate, acetone,
dimethoxymethane, and mineral oils.
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However, heretofore there has been no general solution to the
problem of ground-based ozone formation that also provides for a fluid
with appropriate performance attributes for an industrial solvent.
5 Summary Of The Invention
The present invention is directed to environmentally preferred
fluids and fluid blends, their use as industrial solvents, and to a method
of reducing ozone formation in a process wherein at least a portion of a
fluid eventually evaporates.
10 The fluids and fluid blends of this invention have been selected
b~y the present inventors for their actual or potential low reactivity in the
complex photochemical atmospheric reaction with molecular oxygen
(02) and nitrogen oxides (NOX) to create ozone.
The present invention provides a means to reduce ozone
formation by photochemical atmospheric reactions from a fluid solvent
composition which is intended at application conditions to at least
partially evaporate into the atmosphere. By properly selecting low
reactive components for a fluid solvent compostion, ozone formation
can be reduced.
For the purposes of the present invention three groups of
reduced ozone reactivity fluids and their uses are described and
claimed: (a) Low Polluting Potential Fluid (LPPF), (b) Very Low
Polluting Potential Fluid (VLPPF), and (c) Negligibly Polluting Potential
Fluid (NPPF), according to the Absolute MIR numbers as follows:
Fluid Solvent Designation Absolute MIR
Low Polluting Potential Fluid >1.0-<=1.5 gm ozone produced/gm
fluid
Very Low Polluting Potential Fluid >0.5-<=1.0 gm ozone produced/gm
fluid
Negligibly Polluting Potential Fluid <=0.5 gm ozone produced/gm fluid
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Where a composition is a blend of fluids, a weight average MIR
(WAMIR) can be calculated as
WAMIR = E Wi ~ MIRi
Where Wi. is a weight fraction of solvent fluid component i and MIRi is
the absolute MIR value of solvent fluid component i. For the purposes
of the present invention, WAMIR will be the preferred method of
measuring "ozone formation potential" or OFP.
It is preferred that the fluids and fluid blends also provide at least
one other desirable performance property such as high flash point, low
particulate formation, suitable evaporation rates, suitable solvency, low
toxicity, high thermal stability, and chemical inertness with respect to
non-ozone producing reactions, particularly with respect to acids which
may be present in coating formulations.
In a particularly preferred embodiment, the fluids are used in a
blend with known industrial solvents or other fluids which present an
environmental problem with respect to MIR or lack one or more of the
aforementioned desirable performance properties, so that the new fluid
blends will have lower MIR than they would without the substituted low
ozone formation reactivity fluid or have at least one of the
aforementioned other desirable performance properties.
The present invention is also directed to a method of reducing
ozone formation from atmospheric photochemical reactions in an
application wherein a fluid eventually evaporates, at least partially, into
the atmosphere, comprising replacing at least a portion of a fluid
having a relatively higher MIR with a fluid having a relatively lower MIR.
In the case where a blend results, it is preferred that the weighted
average MIR of the blend be similar to or less than the MIR of a Low
Polluting Potential Fluid, and most preferably similar to the MIR of a
Negligibly Polluting Potential Fluid. .
A fluid or fluid blend according to the present invention may be
used in any process, e.g., any process using a fluid as a carrier,
diluent, dispersant, solvent, and the like, on any scale, e.g., pilot plant
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scale, or industrial scale. It is preferred that the process be a
stationary industrial process and it is preferred that the process is a
non-combustion process. The present invention offers its greatest
benefit from the standpoint of safety and health in large-scale industrial
or commercial processes, particularly industrial coating processes or in
formulations used in large quantities overall, albeit on a small scale for
each individual use, e.g., by a consumer, such as in household paints,
cosmetics, and the like. The ordinary artisan can readily differentiate
between what is an industrial scale, pilot plant scale, and laboratory
scale processes.
Accordingly, it is an object of the present invention to identify
liquid organic compounds not heretofore identified as low reactivity
solvent fluids and have not been used on a large scale commercial
basis to reduce ozone formation.
It is another object of the present invention to provide a method
of selecting fluids and/or fluid blends for applications which release
fluids into the air and wherein there is a need to reduce ozone
formation due to low atmospheric or ground-based (tropospheric)
photochemical reactivity, in order to replace conventional solvents
and/or solvent blends currently used in various compositions or
processes.
It is another object of the present invention to provide a method
of optimizing compositions comprising an evaporative fluid by selecting
a fluid and/or fluid blend providing a reduced MIR as well as at least
one additional performance attribute selected from high flash point,
low particulate formation, suitable evaporation rates, suitable solvency,
low toxicity, high thermal and chemical stability.
Still another object of the present invention includes the
selection of fluids and/or fluid blends providing low reactivity in ozone
formation having compatibility with a wide range of organic compounds
of different polarity and molecular weights to make the fluids and/or
fluid blends suitable for a wide range of compositions.
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It is yet another object of the present invention to provide a
method of reducing ozone formation caused by the release into the
troposphere of a fluid or fluid blend in a process utilizing the fluid or
fluid blend, comprising replacing at least a portion of the fluid with
another fluid having a lower MIR.
A further object is to provide a method of reducing ground-based
ozone formation due to fluid evaporation without resorting to expensive
control equipment to capture all fluid emission into the environment.
Another object is to provide solvents that reduce ground base
ozone formation without the use of halogenated solvents and their
associated toxicity, incineration, and waste disposal issues.
These and other objects, features, and advantages will become
apparent as reference is made below to a detailed description,
preferred embodiments, and specific examples of the present
invention.
Detailed Description Of The Preferred Embodiments
The present invention is directed to An industrial formulation-
fluid system comprising one or more organic volatile formulation-fluids
including a fluid F being substantially free from unsaturated carbon-
carbon bonds or aromatic groups. Fluid F is preferably selected from
the group consisting of: carbonates, acetates, dioxalanes, pivalates,
isobutyrates, propionates, pentanoates, hexanoates, nonanoates,
nitrites and mixtures of any two or more thereof, wherein fluid F is
present in an amount such that the formulation-fluid system exhibits a
reduction in ozone formation in an amount of at least 10%, preferably
at least 25%, and more preferably at least 50% less than that of the
formulation-fluid system without fluid F. Moreover, fluid F has an
ozone formation potential (OFP) (in accordance with the Absolute MIR
scale in units of g. ozone/g. fluid F) of <_ 1.5.
Fluid F preferably comprises an oxygen-containing functional
group or a nitrogen-containing functional group. The oxygen-
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containing functional group is preferably selected from the groups
consisting of: -ROCOOR', -COOR and -ROR', and the nitrogen-
containing functional group is -RCN, wherein R and R' are both
selected from the group consisting of: methyl, ethyl, n-propyl, isopropyl,
isobutyl, tertiary butyl, neopentyl and 2,4,4-trimethylpentyl. Moreover,
hydrocarbyl moieties R and R' have, collectively, a ratio of methyl
hydrogen to non-methyl hydrogen of either (1) greater than 1, (2)
greater than 5, or (3) greater than or equal to 9.
Fluid F preferably comprises a compound selected from the
group consisting of: dimethyl carbonate, methyl pivalate, methyl ethyl
carbonate; methyl isopropyl carbonate; methyl neopentyl carbonate;
methyl tertiary butyl carbonate; diisopropyl carbonate; neopentyl
acetate; ethylene glycol diacetate; 1,2-propylene glycol diacetate; 1,3-
propylene glycol diacetate; 1,2-butylene glycol diacetate; 1,3-butylene
glycol diacetate; 2,3-butylene glycol diacetate; neopentyl glycol
diacetate; methyl propionate, ethyl propionate, isopropyl propionate
and n-propyl propionate, 2,2-dimethyl dioxolane; 2,2,4-trimethyl '
dioxolane; 2,2,4,5-tetramethyl dioxolane; ethyl pivalate; isopropyl
pivalate; tertiary butyl pivalate; neopentyl pivalate; pivalonitrile;
ethylene glycol monopivalate; 1,2-propylene glycbl monopivalate; 1,2-
butylene glycol monopivalate; 2,3-butylene glycol monopivalate;
ethylene glycol pivalate acetate; ethylene glycol dipivalate; 1,2- .
propylene glycol pivalate acetate; 1,2-butylene glycol pivalate acetate;
1,3-butylene glycol pivalate acetate; 2,3-butylene glycol pivalate
acetate; 1,2-propylene glycol dipivalate; neopentyl glycol monopivalate;
neopentyl glycol pivalate acetate; isopropyl isobutyrate; neopentyl
isobutyrate; methyl 2,2,4,4-tetramethyl pentanoate (methyl
neononanoate), isopropyl neononanoate; 2,2,4,4-tetramethyl
pentanonitrile; neopentyl glycol monoisobutyrate; methyl 3,5,5-
trimethylhexanoate, and mixtures of any two or more thereof.
The present invention also includes an industrial formulation-
fluid system comprising one or more organic volatile formulation-fluids
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including a fluid F being substantially free from unsaturated carbon-
carbon bonds or aromatic groups, wherein fluid F is selected from the
group consisting of: carbonates, acetates, dioxalanes, pivalates,
isobutyrates, propionates, pentanoates, hexanoates, nonanoates,
5 nitrites and mixtures of any two or more thereof, and wherein fluid F is
present in an amount such that the formulation-fluid system has an
ozone formation potential (OFP) that is at least 10% less than that of
the formulation-fluid system without fluid F.
The present invention also pertains to a non-combustion
10 process utilizing a process fluid or composition comprising a first fluid
wherein at least some of the first fluid evaporates into the atmosphere,
wherein the process involves replacing at least a portion of the first
fluid with a second fluid, i.e., fluid F, wherein fluid F has an ozone
formation potential (OFP) (in accordance with the Absolute MIR scale
15 in units of g. ozone/g. fluid F) of <_ 1.5 and is present in an amount such
that the process fluid has an OFP that is at least 10% less than that of
the process fluid without fluid F, thereby decreasing ozone formation
from atmospheric photochemical reactions resulting from performance
of the process.
The process fluid according to the present invention preferably
acts as a solvent, carrier, diluent, surface tension modifier, or any
combination thereof, in the process. Moreover, the process fluid does
not contain a halocarbon.
The present invention also pertains to a composition comprising:
(1 ) a first fluid wherein at least some of the first fluid evaporates into
the atmosphere; and (2) a second fluid comprising an oxygen-
containing functional group or a nitrogen-containing functional group
and being substantially free from unsaturated carbon-carbon bonds or
aromatic groups. The second fluid being selected from the group
consisting of carbonates, acetates, dioxalanes, pivalates, isobutyrates,
pentanoates, hexanoates, nonanoates, nitrites and mixtures of any two
or more thereof, wherein the second fluid has an ozone formation
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potential (OFP) (in accordance with the Absolute MIR scale in units of
g. ozone/g, fluid F) of <_ 1.5 and is present in an amount such that the
composition has an OFP of, or reduces ozone formation by, at least
10% less than that of the composition without the second fluid.
The fluids used in accordance with this invention have been
selected for their low or reduced ozone formation potential (as reflected
in their low or reduced M!R). The ozone formation potential of a
composition or fluid solvent may be determined by any scientifically
recognized or peer reviewed method including but not limited to, the
MIR scale, the K°H scale, smog chamber studies, and modeling
studies
such as those performed by Dr. William P. L. Carter. Most references
in the description of the present invention will be to the Absolute MIR
scale measured in grams ozone produced/gram of fluid solvent. By
"low MIR" is meant that the fluids have an MIR similar to or less than
1.5 gram of ozone per gram of the solvent fluid. By "reduced MIR" is
meant that, in a process according to the present invention, a first fluid
is replaced, in whole or in part, by a second fluid, the second fluid
having an MIR lower than the first fluid. One of ordinary skill in the art
can determine ozone reactivity of a material according to methods in
numerous literature sources and tabulated data published in the open
literature. It is mentioned that the terms "replace", "replacement",
"replacing" and the like used herein are not to be taken as implying
only the act of substituting a second fluid (having acceptable MIR as
described herein) in a formulation for a first fluid that may have been
previously used in that and similar formulation(s), with such first fluid
has undesirable MIR as described herein. Rather, the terms are
intended to include the formulations themselves comprising a mixture
of the first and second fluids, or one or more such second fluids)
without any of said first fluid(s), as the fluid system of the formulation.
In the case where no such first fluids) are present, the concept of
"replacement" is intended to refer to corresponding formulations that
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17
have only such first fluids) present instead of such second fluids) and
therefore have a lower OFP.
The MIR is preferably determined by smog chamber studies,
modeling studies, or a combination thereof, but is more preferably
determined by "incremental reactivity", and still more preferably by the
Absolute MIR, as discussed above.
The MIR of a fluid used in this invention is preferably less than
or equal to 1.5 gram of ozone per gram of solvent fluid, more preferably
less than or equal to 1.0 gram of ozone per gram of solvent fluid, and
most preferably less than or equal to 0.5 gram of ozone per gram of
solvent fluid, but the benefits of the present invention are realized if
ozone formation is reduced by replacing a first fluid with a second fluid,
in whole or in part, wherein the MIR of the second fluid is reduced from
that of the first fluid, even if the second fluid has an MIR greater than
1.5 gram of ozone per gram of solvent fluid.
Therefore, it'is preferred that the fluid according to the present
invention have an MIR less than or equal to 1.50 and more preferably
less than or equal to 1.00, still more preferably less than or equal to
0.50. In an even more preferred embodiment, the reactivity in ozone
formation is preferably equal to or less than that of acetone and even
more preferably equal to or less than that of ethane, by whatever scale
or method is used, but most preferably by the MIR scale. Thus, in a
more preferred embodiment, the fluid used in a composition according
to the present invention will have an MIR less than or equal to 0.50,
even more preferably less than or equal to 0.35.
Specifically preferred fluids according to the present invention
include:
dialkyl carbonates, such as dimethyl carbonate (DMC), methyl
ethyl carbonate, methyl isopropyl carbonate, methyl sec-butyl
carbonate, methyl t-butyl carbonate, methyl neopentyl carbonate, and
diisopropyl carbonate;
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alkyl acetates, such as neopentyl acetate, ethylene glycol
diacetate, 1,2-propylene glycol diacetate, 1,3-propylene glycol
diacetate, 1,2-butylene glycol diacetate, 1,3-butylene glycol diacetate,
2,3-butylene glycol diacetate, neopentyl glycol diacetate;
dioxolanes such as 2,2-dimethyl dioxolane, 2,2,4-trimethyl
dioxolane, 2,2,4,5-tetra methyl dioxolane;
pivalates such as methyl pivalate (methyl 1,1,1-trimethyl
acetate), ethyl pivalate, isopropyl pivalate, t-butyl pivalate (TBP),
neopentyl pivalate (NPP), 1,2-propylene glycol bis-pivalate (PGBP),
ethylene glycol bis-pivalate, ethylene glycol monopivalate, 1,2-butylene
glycol mono-pivalate (1,2-BGMP), 2,3-butylene glycol monopivalate
(2,3-BGMP), 1,2-butylene glycol pivalate acetate (1,2-BGPA), 1,2-
butylene glycol pivalate acetate (1,2-BGPA), 2,3-butylene glycol
pivalate acetate (2,3-BGPA), ethylene glycol pivalate acetate, 1,2
propylene glycol monopivalate, neopentyl glycol mono pivalate, and
1,2-propylene glycol pivalate acetate;
isobutyrate compounds such as isopropyl isobutyrate, neopentyl
isobutyrate, and neopentyl glycol mono isobutyrate;
propionate compounds such as methyl propionate, ethyl
propionate, isopropyl propionate and n-propyl propionate; and
2,2,4,4-tetramethyl pentanonitrile (TMPN); isopropyl
neononanoate; pivalonitrile; methyl 2,2,4,4-tetramethyl pentanoate
(methyl neononanoate) and methyl 3,5,5 trimethyl hexanoate. Other
preferred fluids are oxygenated (oxygen containing) organic
compounds substantially free of moieties containing unsaturated
carbon-carbon bonds or aromatic groups.
In the case of a blend, the weighted average MIR of the fluids in
a composition according to the present invention will also have the
perferred, more preferred, and most preferred MIR levels as discussed
above.
In another preferred embodiment, wherein the blend results from
replacing part of a first fluid with a second fluid and thereby reducing
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19
the weight average MIR, it is preferred that the weight average MIR be
reduced 10%, more preferably 25%, still more preferably 50%, from the
MIR calculated prior to the fluid replacement.
In yet another preferred embodiment, the Low Polluting Potential
Fluids (LPPF), Very Low Polluting Potential Fluids (VLPPF), and
Negligibly Polluting Potential Fluids (NPPF), as described herein will
provide at least one other desirable performance property such as high
flash point low particulate formation, suitable evaporation rates,
suitable solvency, low toxicity, high thermal stability, and chemical
inertness. Of course, it is more preferable that the fluid or blends have
two or more of these performance attributes, and so on, so that the
most preferred fluid or fluid blend has all of these performance
attributes.
In the case of a process of reducing ozone formation, wherein a
fluid according to the present invention replaces a fluid, at least in part,
having a higher MIR, described in more detail below, it is preferred that
this fluid replacement process, in addition to reducing ozone formation
does not negatively impact any other desirable performance attributes
of the composition as described above.
The flash point of a fluid according to the present invention is
preferably at least -6.1 °C or higher, more preferably greater than
+6.0°C, even more preferably greater than 15°C, still more
preferably
greater than 25°C, yet even more preferably greater than 37.8°C,
dnd
most preferably greater than 60°C. One of ordinary skill in the art can
readily determine the flash point of a fluid or blend (e.g., ASTM D92-
78).
In the case of a blend, the flash point of the blend may be the
flash point of the more volatile component, in the instance where the
flash points of the individual components differ markedly or where the
more volatile component is the predominant component. The flash
point of the blend may be in between the flash points of the individual
components. As used herein, the term "flash point" will refer to the
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flash point experimentally determined for a single fluid or a blend, as
applicable.
The fluid or blend thereof, according to the present invention,
should preferably not contribute measurably to particulate formation of
5 particulates having a size diameter below 2.5 pm - referred to as
2.5PM herein - in the atmosphere. In a preferred embodiment of a
process of reducing ozone formation, the fluid selected to replace a
previously-used solvent will be one that also reduces particulate matter
to less than or equal to 65 pg/m3, and more preferably less than or
10 equal to 50 pg/m3, when measured over a 24-hour period, preferably
spatially averaged over all monitors in a given geographic area.
The evaporation rate should be suitable for the intended
purpose. In many if not most applications., the fluid according to the
present invention will be used to replace, at least in part, a fluid which
15 is environmentally disadvantaged, meaning it has a reactivity in ozone
formation greater than 1.5 in Absolute MIR units. The fluid selected
preferably will have a similar evaporation rate to the disadvantaged
fluid being replaced, particularly in the case where a fluid blend is used
and an acceptable evaporation profile is desired. It is convenient for
20 the fluid selected to have an evaporation rate less than 12 times the
evaporation rate of n-butyl acetate. Evaporation rates may also be
given relative to n-butyl acetate at 1.0 (ASTM D3539-87). Ranges of
evaporation rates important for different applications are 5-3, 3-2, 2-1,
1.0-0.3, 0.3-0.1, and <0.1, relative to n-butyl acetate at 1Ø The
present invention is related to fluids and fluid blends that at least
partially evaporate into the atmosphere during or after their application.
The use of fluids of the present invention is preferred when >25% of
the fluid is evaporated, more preferably when >50% of the fluid is
evaporated, more preferably when >80% of the fluid is evaporated,
more preferably when >95% of the fluid is evaporated, and most
preferably when >99% of the fluid is evaporated. In a preferred
embodiment of the present invention wherein, in a method of reducing
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21
ozone formation, a fluid according to the present invention replaces, at
least in part, another fluid not according to the present invention, the
fluid replaced has an evaporative rate ranging from that of MEK
(methyl ethyl ketone) to less than that of n-butyl acetate.
The fluid or fluid blend according to the present invention may
act in the traditional manner of a solvent by dissolving completely the
intended solute or it may act to disperse the solute, or it may act
otherwise as a fluid defined above. It is important that the solvency of
the fluid be adequate for the intended purpose. In addition to the
required solvency, the formulated product must be of a viscosity to
enable facile application. Thus, the fluid or fluid blend must have the
appropriate viscosities along with other performance attributes. One of
ordinary skill in the art, in possession of the present disclosure, can
determine appropriate solvent properties, including viscosity.
Toxicity relates to the adverse effect that chemicals have on
living organisms. One way to measure the toxic effects of a chemical
is to measure the dose-effect relationship; the dose is usually
measured in mg of chemical per kg of body mass. This is typically
done experimentally by administering the chemical to mice or rats at
several doses in the lethal range and plotting the logarithm of the dose
versus the percentage of the population killed by the chemical. The
dose lethal to 50% of the test population is called the median lethal
dose (LD50) and is typically used as a guide for the toxicity of a
chemical. See, for instance, Kirk-Othmer Encyclopedia of Chemical
Technology, Fourth Edition, Vol. 24, pp. 456-490. Currently an LD50 of
>500 mg/kg qualifies as "not classified" for oral toxicity under OSHA
rules. EU (European Union) uses a cutoff of >2,000 mg/kg. It is
preferred that the fluid or fluid blend according to the present invention
have an oral rat LD50 of >500 mg/kg, more preferably >1000 mg/kg,
still more preferably >2,000 mg/kg, even more preferably >3,000
mg/kg, and most preferably >5,000 mg/kg. Likewise, the fluid or blend
should also cause no toxicity problems by dermal or inhalation routes
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and should also not be an eye or skin irritant, as measured by OSHA or
European Union (EU) standards.
As described above, the present invention is related to fluid
solvents and fluid solvent blends which produce reduced ozone
formation due to atmospheric photochemical reactions and which avoid
the deficiencies associated with halogenated organic compounds,
particularly toxicity, ozone depletion, incineration by-products and
waste disposal problems. In this aspect, the volatile components of the
preferred fluid solvents and fluid solvent blends preferably do not have
more than 2.0 wt. % of halogen and more preferably less than 0.5 wt.
%, and most preferably less than 0.1 wt. %.
The fluid according to the present invention should be thermally
stable so that it does not break down. For instance, the material
should not break down into reactive species. In a preferred
embodiment, the fluid is more thermally stable than t-butyl acetate.
Inertness, as used herein, refers to the lack of a tendency to
undergo decomposition with other materials in the fluid system. It may
include, for example, inertness towards acids or bases, but particularly
to acid catalysts, which are typically present in coating compositions.
It is preferred that the fluid being replaced have an MIR greater
than that of acetone. In another embodiment, the incremental
reactivity, based on the MIR scale, of the fluid being replaced is
preferably >0.50, still more preferably >0.1.00, and most preferably
> 1.50.
In another embodiment, it is critical that in a process of reducing
tropospheric ozone formation according to the present invention, the
fluid replaced have a greater MIR than the fluid added, that is, the fluid
according to the present invention. Of course it is to be recognized that
only a portion of the higher MIR fluid need be replaced, thus obtaining
a blend, in order to achieve the ozone formation reduction.
However, in another embodiment of the present invention, the
fluid being replaced may have an acceptable MIR, but be unacceptable
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23
with respect to one or more of the aforementioned performance
attributes of flash point or flammability, parfiiculate formation,
evaporation rate, solvency, toxicity, thermal stability, or inertness.
Examples of a given blend of DMC and MEK will be provided wherein
the appropriate addition of DMC (or "replacement" of acetone) provided
for an improvement in at least one of these attributes.
Examples of fluids which are replaced by fluids according to the
present invention include aromatic and aliphatic hydrocarbon fluids
such as: branched C6-C9 alkanes, straight chain alkanes, cycloaliphatic
1 O C6-C~p hydrocarbons, natural hydrocarbons (alpha or beta pinenes, or
turpentines, etc.), ethanol, propanol and higher nontertiary alcohols, C3
and higher ethers, ether alcohols, ether alcohol acetates, ethyl ethoxy
propionate, C5 and higher ketones, cyclic ketones, etc., C~+ aromatic
hydrocarbons; halocarbons, particularly chlorinated and brominated
hydrocarbons; and ethers such as cyclic ethers such as
tetrahydrofuran (THF),. Examples of other common industrial solvents
which may be replaced by fluids according to the present invention are
those listed in Kirk-Othmer Encyclopedia of Chemical Technology,
Fourth Edition, Vol. 22, p. 536-548.
Some particularly preferred replacements, i.e., a fluid according
to the present invention for a currently used industrial solvent, include:
in any application, but particularly coatings applications, DMC or methyl
pivalate for toluene, xylene, or t-butyl acetate; methyl isopropyl
carbonate (MIPC) for xylene or methyl isobutyl ketone (MIBK); and
diisopropyl carbonate (DIPC) for methyl amyl ketone (MAK), propylene
glycol monomethyl ether acetate (PMAc), or ethyl ethoxy propionate
(EEP); in any application, but particularly consumer product
applications DMC, MIPC, or DIPC for hydrocarbons; in any application
but particularly agricultural applications, DIPC for aromatic fluids; in any
application but particularly cleaning applications, DIPC or methyl sec-
butyl carbonate (MSBC) for chlorinated solvents; in any application, but
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particularly inks, substitute DMC or methyl pivalate for MEK and light
acetates.
The fluids and blends according to the present invention may be
used in any process using a fluid, and particularly those process
wherein at least a portion of the fluid evaporates and even more
particularly wherein at least a portion evaporates into the atmosphere.
Preferred processes are those utilizing the fluid as one or more of a
carrier, diluent, dispersant, solvent, and the like, include processes
wherein the fluid functions as an inert reaction medium in which other
compounds react; as a heat-transfer fluid removing heat of reaction; to
improve workability of a manufacturing process; as a viscosity reducer
to thin coatings to application viscosity; as an extraction fluid to
separate one material from another by selective dissolution; as a
tackifier or to improve adhesion to a substrate for better bonding; as a
dissolving medium to prepare solutions of polymers, resins, and other
substances; to suspend or disperse pigments and other particulates;
and the like.
It is preferred that the process be a stationary process and also
preferred that the process be a non-combustion process. It is
particularly beneficial if the fluid according to the present invention be
used to replace at least a portion of a traditional industrial solvent in a
process using a large amount of fluid, e.g., a process using 1000
Ib/year (500 kg/year), even more preferably 5 tons/year (5000 kg/yr),
still more preferably 50 tons/year (50,000 kg/yr), and most preferably
one million Ibs/year (500,000 kg/yr). In a preferred embodiment, the
process wherein the aforementioned fluid replacement occurs is on the
scale of at least pilot plant-scale or greater.
It is also preferred that the process in which a fluid or blend
according to the present invention is used or in which at least one fluid
according to the present invention replaces, at least partially, a fluid
having a higher MIR, be a process in which the fluid is intended to
evaporate, such as in a coating process. In such a process were the
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fluid is intended to evaporate, it is preferred that at least 10% of the
fluid or fluids evaporate, more preferably 20% of the fluids, and so on,
so that it is most preferable if >99% of the fluid or fluids present in the
coating evaporate.
5 Furthermore, one of the greatest environmental benefits of
replacing a currently-used industrial solvent with a solvent according to
the present invention will be realized if performed in a geographic area
where monitoring for ozone and particulate matter formation occurs,
and more particularly in geographic areas defined by a city and its
10 contiguous area populated by at least 500,000 persons, and wherein
the replacement of at least a portion of the currently-used industrial
solvent with a fluid according to the present invention causes at least
one of:
(i) a reduction in the ozone formation, as measured by either
15 monitoring devices or by a calculation of the reduction using the MIR of
the industrial solvent replaced and the fluid added according to the
present formation; or
(ii) a reduction in particulate formation of particles having a
diameter less than 2.5 pm (2.5PM), preferably measured as a 24 hour
20 standard, more preferably wherein that reduction is from greater than
65 pg/m3 to less than that amount in a 24 hour period, still more
preferably from greater than 65 ~tg/m3 to less than or equal to 50
pg/m3 in a 24 hour period;
and more preferably both (i) and (ii).
25 In another embodiment, there is a method of selecting a fluid for
use in a process wherein at least a portion of the fluid eventually
evaporates into the atmosphere, comprising selecting as the fluid a
blend of:
(a) at least one fluid A having a low MIR, preferably similar to or
less than or equal to 1.50, more preferably less than or equal to 1.00, ,
yet still more preferably wherein the MIR is less than or equal to 0.50
and still even more preferably less than or equal to 0.35; and
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(b) at least one fluid B characterized by having at least one
unsuitable attribute selected from: (i) high MIR, preferably measured by
the MIR scale, e.g., having an MIR>0.50, more preferably >1.00, and
yet even more preferably >1.50; (ii) low flash point, preferably less than
or equal to 37.8°C, more preferably less than or equal to 25°C,
even
more preferably less than or equal to 15°C, yet even more preferably
less than or equal to 6.0°C, and most preferably less than -6.1
°C; (iii)
formation of 2.5 PM particulates (e.g., wherein said process, using fluid
B, produces 2.5 PM greater than 65 micrograms per cubic meter or
greater, as measured in a 24-hour period); (iv) toxicity, preferably those
having an oral rat LD50 less than or equal to 1,000 mg/kg, and most
preferably less than or equal to 500 mg/kg; (vi) thermal stability,
preferably having a thermal stability equal to or less than (more
unstable) than t-butyl acetate; and (vii) inertness in the fluid or fluid
blend, particularly with respect to any acids or bases present in the
fluid or blend.
Preferred examples of fluid A include:
dialkyl carbonates, such as dimethyl carbonate (DMC), methyl
ethyl carbonate, methyl isopropyl carbonate, methyl sec-butyl
carbonate, methyl t-butyl carbonate, methyl neopentyl carbonate, and
diisopropyl carbonate;
alkyl acetates, such as neopentyl acetate, ethylene glycol
diacetate, 1,2-propylene glycol diacetate, 1,3-propylene glycol
diacetate, 1,2-butylene glycol diacetate, 1,3-butylene glycol diacetate,
2,3-bufiylene glycol diacetate, neopentyl glycol diacetate;
dioxolanes such as 2,2-dimethyl dioxolane, 2,2,4-trimethyl
dioxolane, 2,2,4,5-tetra methyl dioxolane;
pivalates (trimethyl acetates) such as methyl pivalate (MP),
isopropyl pivalate, t-butyl pivalate (TBP), neopentyl pivalate (NPP), 1,2-
propylene glycol bis-pivalate (PGBP), ethylene glycol bis-pivalate,
ethylene glycol monopivalate, 1,2-butylene glycol mono-pivalate (1,2-
BGMP), 2,3-butylene glycol monopivalate (2,3-BGMP), 1,2-butylene
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glycol pivalate acetate (1,2-BGPA), 1,2-butylene glycol pivalate acetate
(1,2-BGPA), 2,3-butylene glycol pivalate acetate (2,3-BGPA), ethylene
glycol pivalate acetate, 1,2 propylene glycol monopivalate, neopentyl
glycol mono pivalate, and 1,2-propylene glycol pivalate acetate;
isobutyrate compounds such as
isopropyl isobutyrate, neopentyl isobutyrate, and neopentyl glycol
mono isobutyrate;
propionate compounds such as methyl propionate, ethyl
propionate, isopropyl propionate and n-propyl propionate; and
2,2,4,4-tetramethyl pentanonitrile (TMPN); isopropyl
neononanoate; pivalonitrile; methyl 2,2,4,4-tetramethyl pentanoate
(methyl neononanoate); and methyl 3,5,5 trimethyl hexanoate.
Preferred examples of fluid B include aromatic and aliphatic
hydrocarbon fluids such as toluene and xylenes; alcohols such as
ethanol, n-butyl alcohol, n-propyl alcohol, and sec-butanol; esters such
as ethyl ethoxy propionate propylene glycol methyl ether acetate;
ketones such as methyl ethyl ketone (MEK), C5-Coo linear ketones, ,
cyclic ketones; halocarbons, particularly chlorinated and brominated
hydrocarbons; cyclic ethers such as THF, and non-cyclic ethers such
as methyl tert-butyl ether (MTBE).
The present invention also concerns mixtures or blends of at
least one fluid according to the present invention and fluids which are
known to have acceptable low OFP, e.g., acetone (MIR=0.48), methyl
acetate (MIR=0.12), tert-butyl acetate (MIR=0.21 ), tertiary butanol
(MIR=0.40), dimethyl succinate (MIR=0.20), dimethyl glutarate
(MIR=0.40), and propylene carbonate (MIR=0.43). Such blends can
have some important advantages, for example, blends of DMC and
MEK, or DMC and methyl acetate, as previously mentioned. These
blends are also considered to be part of the present invention. In
combination with fluids having an MIR higher than 0.50, the fluids still
can provide significant reduction in ozone formation for blended fluid
compositions with other important properties for the particular
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application. Therefore, fluid compositions with low or reduced OFP
comprising solvents selected from the list above are important goals of
the present invention, even if their weighted OFP is above 0.50 in the
MIR scale.
The fluids listed above are recommended to be used in solvent
compositions intended for release into air and are required to provide
low reactivity in ozone formation. The solvents selected according to
the present invention can be used in blends with each other as well as
in blends with other solvents (e.g., solvents B, above), different from
the solvents of the present invention. When all solvents included in the
blend have MIR reactivity ~ 0.50 or less, the solvent blends also will
have low atmospheric photochemical reactivity with MIR of about 0.50
and less.
The present inventors have found that many solvent blends can
have an MIR in the range of ethane or acetone, even though one
component may exceed that range, and therefore in terms of reactivity
toward ozone formation behave as exempt solvents. The range of
reactivities in exempt solvents allows a selection of fluids with
extremely low reactivity, with MIR number in range of <0.35 and more
suitably <0.24. These fluids can be blended not only with fluids with
reactivity based on MIR of 0.50 or less but, with appropriately
selected fluids with MIR numbers >0.50 and at certain ratios still form
fluid compositions with weighted reactivity about 0.50 or less. These
blends can significantly expand the range of properties of solvent
compositions and provide formulators with necessary flexibility for
different applications. The selection of fluids with MIRs >0.50 can be
relatively wide, however, to achieve significant reduction in weighted
reactivity to 0.50 or less, it is recommended to choose solvent with
MIR <1.5, suitably <1.2, and more suitably <1Ø
The conception of blends demonstrating MIR of about 0.50 or
less can be applied to other solvents with known extremely low
reactivities. For example, methyl acetate has an MIR 0.12 but flash
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point ~ -12°C. Thus, methyl acetate can be blended with butyl acetate
(MIR = 1.00 and flash point 27°C) in weight ratio of 57:43 forming a
blend with MIR = 0.50, providing reactivity similar to exempt solvents.
This blend would have a better flash point and lower evaporation rate,
making it useful for many applications which methyl acetate could not
satisfy due to very low flash point. Butyl acetate which is not an
exempt solvent, would become part of a mixture which by its weighted
reactivity would behave similar to exempt solvent and, therefore,
constitute preferred solvent composition. °
This special case of blends comprising at least one solvent with
MIR reactivity <0.50 and at least one solvent with MIR >0.50 which
have their weighted reactivity about 0.50 or less is one very important
part of the present invention. Among known solvents with extremely
low MIR, suitable components for the preferred blended solvents are
methyl acetate (MIR = 0.12), t-butyl acetate (MIR = 0.21 ), dimethyl
succinate (MIR = 0.20) and methyl siloxanes including
cyclomethylsiloxanes. Blends of these solvents with other solvents
with MIR >0.50 resulting in weighted MIR of about 0.50 or less for the
blend are preferred solvents according to the present invention.
However, some of the most interesting blends are the blends of
at least one solvent with MIR reactivity <0.50 and with at least one with
MIR reactivity >0.50, which can be generated with the solvents from
the list of the present invention.
The present invention offers fluids and fluid blends for use in a
variety of industrial applications such as paints and other coatings,
adhesives, sealants, agricultural chemicals, cleaning solution,
consumer products such as cosmetics, pharmaceuticals, drilling muds,
extraction, reaction diluents, inks, metalworking fluids, etc.
Among the most preferred fluids according to the present
invention are dimethyl carbonate and methyl pivalate. Table 1
demonstrates the extremely low relative reactivities - significantly lower
than both acetone and ethane - of dimethyl carbonate and methyl
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pivalate. This data shows that these two compounds satisfy the EPA
requirements for exempt solvents in accordance with current VOC
regulations and demonstrating extremely low reactivity for the possible
future reactivity based rules. Additionally, DMC is shown to be one of
5 the lowest reactivity compounds among all currently known oxygenated
compounds.
TABLE 1
Summary of calculated incremental reactivites (gram basis) for
10 ethane, acetone, dimethyl carbonate, and methyl pivalate,
relative to the average of all VOC emissions.
Ozone Max.
Yield 8
Relative Hour
Reactivities Ava.
Relative
Reactivities
Scenario EthaneAcetoneDMC Me- EthaneAcetoneDMC Me-
Pvat Pvat
Max React0.09 0.12 0.02 0.060.08 0.15 0.04 0.07
Max Ozone0.16 0.14 0.04 0.110.10 0.15 0.05 0.09
Equal 0.21 0.15 0.05 0.120.12 0.15 0.07 0.09
Benefit
Table 2a shows the conversion of a portion of the data in Table
15 1 into Absolute Maximum Incremental Reactivities for the dimethyl
carbonate and methyl pivalate. As seen from Table 2, Absolute Ozone
Formation for different levels of NOx in ROG is highest for highest level
of NOx scenario (MIR) and lowest for lowest level of NOx scenario
(EBIR). As a result, Absolute Reactivity in atmospheric photochemical
20 ozone formation for tested compounds is highest for MIR scenario and
lowest for EBIR scenario. This data demonstrates the outstanding
value as Low Polluting Potential Fluids (LPPF), Very Low Polluting
Potential Fluid (VLPPF), and Negligibly Polluting Potential Fluid
(NPPF). Additionally Table 2b shows both compounds as having
25 acceptable flash points, boiling temperatures, evaporation rates, low
toxicity, good solvency and overall outstanding performance as
versatile environmentally preferred exempt, extremely low ozone
formation fluids (solvents) for a very wide range of applications.
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Table 2a - Absolute Reactivity Conversion Ratios
ROG EthaneAcetonDMC MP
Ozone Yield MIR 1 0.09 0.12 0.02 0.06
Relative
Reactivities MOIR 1 0.16 0.14 0.04 0.11
EBIR 1 0.21 0.15 0.05 0,12
Ozone Yield MIR 3.93 0.354 0.472 0.079 0.236
Absolute
Reactivities MOIR 1.41 0.226 0.197 0.056 0.155
EBIR 0.82 0.172 0.123 0.041 0.098
I
Table 2b - Fluid Solvent Properties
AcetoneDMC MP
Boiling Temperature, 56 90 99
C
Viscosity (cps, 20C) 0.33 0.60 0.74
Specific Gravity 0.792 1.065 0.873
Surface Tension 22.3 29.0 23.8
Flash Point (C) -20 +19 to +32 27.2
* *
Evaporation Ratio 18 3.2 2.2
to Butyl Acetate
Total 9.2 9.8 8.1
Hansen
Solubility Nonpolar 7.6 7.6 7.2
Parameter Polar 5.1 3.6 1.8
H-Bouding3.4 4.9 3.1
Toxicity (LD-50, 5800 13000
mg/kg)
* Reflects Varied
Reported Literature
Data varies
Likewise, dimethyl carbonate (DMC) is highly preferable and can
be blended with another organic solvent, even one having an Absolute
MIR greater than 0.50 to form a solvent system that would still have an
Absolute MIR of less than 0.50. DMC blended with another organic
solvent would also exhibit other desirable environmental properties
because DMC has a relatively high flash point and low toxicity. Again,
heretofore unrecognized as a low OFP fluid, the Relative MIR of DMC
is calculated to be 0.02, using the SAPRC97 model.
The compounds presented in Tables 3-5 show calculated
Absolute MIR reactivities for compounds useful as Low Polluting
Potential Fluids (LPPF), Very Low Polluting Potential Fluids (VLPPF),
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and Negligibly Polluting Potential Fluids (NPPF) or as part of a fluid
solvent blend. These fluids provide favorable MIR reactivities, a very
wide range of evaporation rates, and a wide range of solvency and
compatability with other solvents, polymers, pigments, catalysts,
additives, etc., necessary for actual applications. All the compounds
listed in the present invention, especially in Tables 2a - 5, are very
useful as substitute conventional solvents having an Absolute MIR
between 1.5 and 3.0 and especially in solvents having high reactivity
Absolute MIR greater than 3.0 in atmospheric photochemical ozone
formation.
Table 3 - Calculated Absolute MIR Reactivities F'or
Nealiaibly Polluting Potential Fluids
Compound Absolute MIR
~aram ozone produced/aram
fluid)
Dimethyl Carbonate 0.079 (Actual measured
value)
Methyl Pivalate 0.236 (Actual measured
value)
Methyl Tertiary Butyl Carbonate0.246
Tertiary Butyl Pivalate 0.324
Pivalonitrile <= 0.200 (Expected value)
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Table 4 - Calculated Absolute MIR Reactivities For Very
Low Polluting Potential Fluids
Compound Absolute MIR
(gram ozone produced/~ram
fluid
Ethylene Glycol Dipivalate 0.538
Methyl Propionate 0.600
Diisopropyl Carbonate 0.606
Methyl Ethyl Carbonate ' 0.649
Ethyl Pivalate 0.657
Ethylene Glycol Pivalate Acetate 0.667
1,2-Propylene Glycol Dipivalate 0.697
Neopentyl Pivalate 0.700
Neopentyl Glycol Diacetate 0.743
Methyl Neopentyl Carbonate 0.800
1,3-Propylene Glycol Diacetate 0.826
Ethyl Propionate 0.860
Neo Pentyl Isobutyrate 0.862
Ethylene Glycol Diacetate 0.870
1,2-Propylene Glycol Monopivalate 0.884
1,2-Propylene Glycol Pivalate Acetate0.890
(Mix)
1,2-Butylene Glycol Monopivalate 0.901
Neopentyl Acetate 0.908
Methyl Isopropyl Carbonate 0.918
Isopropyl Isobutyrate 0.930
1,2-Butylene Glycol Pivalate Acetate0.934
(Mix)
2,3-Butylene Glycol Monopivalate 0.930
2,3-Butylene Glycol Pivalate Acetate0.960
Isopropyl Pivalate 0.971
N-Propyl Propionate 0.990
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Table 5 - Calculated Absolute MIR Reactivity For Low
Polluting Potential Solvents
Compound Absolute MIR
(cram ozone produced/gram
fluid)
NeoPentyl Glycol Monopivalate 1.062
1,2-Propylene Glycol Diacetate 1.196
1,2-Butylene Glycol Diacetate 1.254
Methyl Secondary Butyl Carbonate 1.278
Methyl 3,5,5 Trimethyl Hexanoate 1.322
2,3-Butylene Glycol Diacetate 1.332
Ethylene Glycol Mono Pivalate 1.365
1,3-Butylene Glycol Diacetate 1.373
It should be noted that calculated values for the Absolute and the
Relative MIR reactivity for DMC and MP were very close to the actual
laboratory determined values.
The most preferred use of the fluids according to the present
invention is with any process wherein the reduction of ozone formation
is desired, and more particularly in consumer products, and coatings
such as auto refinishing, architectural and industrial coatings and
paints.
Paints and coatings comprise the largest single category of
traditional solvent consumption, accounting for nearly half the solvents
used. Fluids serve multiple functions in paints and coatings, including
solubility, wetting, viscosity reduction, adhesion promotion, and gloss
enhancement. Fluids dissolve the resins, dyes and pigments used in
the coating formulations. Also, prior to application, it is common
practice to add solvent thinner to attain the desired viscosity for the
particular application. Solvents begin to evaporate as soon as the
coating materials are applied. As the solvent evaporates, film
formation occurs and a continuous, compact film develops. Single
solvents are sometimes used in coatings formulations, but most
formulations are blends of several solvents. In many coatings
applications, the solvent system includes a slow-evaporating active
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solvent that remains in the film for an extended period to enhance the
film's gloss and smoothness. Because of evaporation and the large
amounts of solvents used in coatings, there is a significant amount of
VOC emissions into the atmosphere.
5 Resins which may be incorporated into compositions comprising
fluids according to the present invention include acrylic, alkyd,
polyester, epoxy, silicone, cellulosic and derivatives thereof (e.g.,
nitrocellulosic and cellulosic esters), PVC, and isocyanate-based
resins. Numerous pigments may also be incorporated into
10 compositions according to the present invention, and it is within the skill
of the ordinary artisan to determine proper selection of the resin and
pigment, depending on the end use of the coating.
Ore of the cleaning applications is cold solvent cleaning which is
used to degrease metal parts and other objects in many operations.
15 Mineral spirits have been popular in cold cleaning, but are being
supplanted by higher flash point hydrocarbon solvents due to
emissions and flammability concerns. Efforts to eliminate organic
solvents entirely from cleaning compositions have not been successful
because aqueous cleaners do not have the performance properties
20 that make organic solvent based cleaners so desirable. This invention
allows formulators the option to seek the use of solvents with very low
reactivity as environmentally preferred products meeting environmental
concerns and customer performance concerns.
A cleaning solution application which uses evaporation to clean
25 is called vapor degreasing. In vapor degreasing, the solvents vaporize
and the cold part is suspended in the vapor stream. The solvent
condenses on the part, and the liquid dissolves and flushes dirt,
grease, and other contaminants off the surface. The part remains in
the vapor until it is heated to the vapor temperature. Drying is almost
30 immediate when the part is removed and solvent residues are not a
problem. The most common solvent used in vapor degreasing
operations has been 1,1,1-trichloroethane. However, since 1,1,1-
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trichloroethane is being phased out due to ozone depletion in the
stratosphere, alternatives are needed. Moreover, chlorine-based
solvents have toxicity concerns. Thus, some of the low reactivity, high
flash point solvents in this invention can be used in place of 1,1,1-
trichloroethane and other halogenated solvents.
An application that is similar to coatings is printing inks. In
printing inks, the resin is dissolved in the solvent to produce the ink.
Most printing operations use fast evaporating solvents for best
production speeds, but the currently used solvents are highly reactive.
Some of the previously described fast evaporation, high flash point, low
reactivity in ozone formation fluids according to the present invention
are suitable for printing inks.
An application that is suitable to the low toxicity, high flash point
and low reactivity in ozone formation fluids according to the present
invention is agricultural products. Pesticides are frequently applied as
emulsifiable concentrates. The active insecticide or herbicide is
dissolved in a hydrocarbon solvent which also contains an emulsifier.
Hydrocarbon solvent selection is critical for this application. It can
seriously impact the efficiency of the formulation. The solvent should
have adequate solvency for the pesticide, promote good dispersion
when diluted with water, have low toxicity and a flash point high enough
to minimize flammability hazards.
Extraction processes, used for separating one substance from
another, are commonly employed in the pharmaceutical and food
processing industries. Oilseed extraction is a widely used extraction
process. Extraction-grade hexane is a common solvent used to extract
oil from soybeans, cottonseed, corn, peanuts, and other oil seeds to
produce edible oils and meal used for animal feed supplements. Low
toxicity, high flash point, low MIR fluids and fluid blends of the present
invention can be useful in such industries.
In addition to the above-mentioned applications, other
applications that can use high flash point, low toxicity, low reactivity in
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ozone formation fluids are adhesives, sealants, cosmetics, drilling
muds, reaction diluents, metal working fluids, and consumer products,
such as pharmaceuticals or cosmetics.
The invention is further described in the following examples,
which are intended to be illustrative and not limiting. One of skill in the
art will recognize that numerous variations are possible within the
scope of the appendaged claims.
Examples of Fluid Blends Having Negligible Reactivity
Tables A and B below demonstrate fluid solvent blends may be
created using (a) negligibly low reactivity fluid solvents and (b) low to
very low reactivity fluid solvent in ratios which provide Weight Average
MIR reactivity for the total solvent blend of < 0.45 and therefore
providing ozone formation similar to individual fluid solvents with
negligibly low reactivity in atmospheric ozone formation. However, the
blends shown in Tables A and B possess characteristics such as better
evaporation profiles, flash points, as compared to the individual fluids.
Table A demonstrates negligibly reactive blends based on a
known negligibly reactive solvent - methyl acetate and other very low
reactivity fluids previously known and from the present invention. In
Table A the column with methyl acetate shows the minimum methyl
acetate content that will provide negligible reactivity to the blend. As
shown, all blends with increased methyl acetate content will result in
reduced reactivity in ozone formation.
However, a main interest in blends with reduced methyl acetate
content that maintain negligible reactivity is in an increased flash point
of the blend. As seen from Table A, especially advantageous are the
two blends with the very low reactivity fluid solvents from the present
invention, diisopropyl carbonate and ethyl pivalate which require the
lowest levels of methyl acetate. This concept of blending the negligible
reactivity compounds with low and very low reactivity secondary fluids
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that can provide Weight Average MIR less than 0.5 is also subject of
this invention.
Although it is not necessary that every component of the blend
be selected from the list of compounds of the present invention, it
should be noted that components selected from the list of the present
invention provide especially desireable attributes to a finished solvent
blend with reduced or negligible reactivity in atmospheric
photochemical ozone formation.
Advantages of the blends created with at least one compound of
the present invention is further demonstrated in Table B which utilizes
blends with DMC as the negligible reactivity component. DMC allows a
high level of the use of the second fluid while maintaining a low MIR
while still providing a fluid solvent with an increased flash point from the
second fluid by itself. The flash points of each of the composition
blends in Table B are > + 6 °C and the majority of them have flash
points > + 15 °C.
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TABLE A
Selected Blends of Methyl Acetate with Other
Very Low Reactivity Solvents at Absolute MIR = 0.45
Very Low ReactivityAbsolute MIR Weight % of Weight % of
Solvent of Second Fluid Methyl Acetate
(Second Fluid Second Fluid Solvent in Blend with
Solvent) Solvent in Blend with Absolute
Absolute MIR = 0.45
MIR = 0.45
Decane 0.93 40.7 59.3
Undecane 0.82 47.1 52.9
Dodecane 0.72 55.0 45.0
Tridecane 0.66 61.1 38.9
Ethyl Propianate0.86 44.6 55.4
Isobutyl Isobutyrate0.86 44.6 55.4
Diacetone Alcohol0.96 39.3 60.7
Diispropyl 0.606 67.9 32.1
Carbonate*
Ethyl Pivalate*0.657 61.5 38.5
* Compounds
of the
present invention
TABLE B
Selected Blends of DMC* with Other Low or
Very Low Reactivity Solvents at Absolute MIR = 0.45
With Flash Points > + 6 °C
Low or Very Absolute MIR Weight % of Weight % of
Low of Second Fluid DMC
Reactivity Second Fluid Solvent in Blend with
Solvent Solvent in Blend with Absolute
(Second Fluid Absolute MIR = 0.45
Solvent) MIR = 0.45
Methyl Ethyl 1.32 29.9 70.1
Ifetone
Isopropanol 0.81 50.8 49.2
Decane 0.93 43.6 56.4
Butyl Acetate 1.14 35.0 65.0
Isopropyllsobutyrate0.86 47.5 52.5
Diispropyl 0.606 70.4 29.6
Carbonate*
Ethyl Pivalate*0.657 64.2 35.8
* Compounds
of the
present invention
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Example 1
A representative solvent/resin system was chosen to evaluate
the sensitivity of a system to solvent changes and evaporation rate
5 differences. Sequential changes to the solvent system were made,
and the impact on resin solubility and evaporation rate profile was
determined.
The initial system consisted of 30 wt% Acryloid B-66 resin (an
acrylic resin available from Rohm & Haas) in a fluid mixture comprised
10 of 40 wt% MEK (methyl ethyl ketone), 40 wt% MIBK (methyl isobutyl
ketone), and 20 wt% Exxate~ 600 (a C6 alkyl acetate available from
Exxon Chemical Company). DMC was substituted in increments for
MIBK, while keeping the rest of the system constant. For example, a
solvent blend of 40 wt% MEK, 35 wt% MIBK, 5 wt°l° DMC and 20 wt%
15 Exxate~ 600 was evaluated, and so on until the final solvent blend
consisted of 40 wt% MEK, 0 wt% MIBK, 40 wt% DMC and 20 wt%
Exxate~ 600. This same procedure was repeated substituting DMC for
MEK, methyl pivalate for MIBK, and methyl pivalate for MEK, while
keeping the rest of the solvent system the same. Ultimately, a solvent
20 blend in which both the MEK and MIBK were replaced by DMC (i.e., 80
wt% DMC and 20 wt% Exxate~ 600) and in which both MEK and MIBK
were replaced by methyl pivalate (i.e., 80 wt% methyl pivalate and 20
wt% Exxate~ 600) was considered. Evaporation profiles were
compared for each solvent blend.
25 The time required to evaporate 10, 50, and 90 wt% of the fluid
was calculated using CO-ACTSM computer program (see, for instance,
Dante et al., Modern Paint and Coafings, September, 1989). The
results are shown below in Table 6.
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Table 6
Evaporation
(minutes) MIR
Wt% in fluid (w/20 wt% Exxate~10% 50% 90% Reduction
600)
40 MEK/40 MIBK 0.7 4.9 46 (comparative)
40 MEK/0 MIBK/40 DMC 0.5 3.8 48 70%
0 MEK/40 MIBK/40 DMC 1.0 6.9 50 19l0
0 MEKIO MIBK/80 DMC 0.8 5.4 55 89%
40 MEK/0 MIBK/40 MP 0.5 3.5 44 68%
0 MEK\40 MIBK/40 MP 0.9 6.3 48 17%
The reduction in MIR is calculated using the known values of
1.34 for MEK, 4.68 for MIBK, and determined values of 0.079 for DMC
and 0.236 for methyl pivalate (MP).
These results show that there is very little difference in the
evaporation profiles between a known resin/solvent system and a
resin/solvent system using the fluids according to the present invention.
Moreover, the above results show the advantage of the process
according to the present invention of reducing ozone formation by
replacing at least a portion of a fluid not having a low ozone formation
potential (MIR>0.50) with a solvent exhibiting a low reactivity in ozone
formation.
Comparative Example 1
The above experiment was repeated using fluids known to have
low reactivity in ozone formation, methyl acetate (MeOAc, MIR = 0.12)
and t-butyl acetate (t-BuOAc, MIR = 0.21 ). The results are shown
below.
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Table 7
Evaporation MIR
minutes
Wt% in fluid w/ 20 wt% 10% 50% 90% Reduction
Exxate~ 600
40 MEK/40 MIBK 0.7 4,9 46 com arative
40 MEK/ 0 MIBK/40 MeOAc0.2 1.6 44 69%
0 MEKl40 MIBiU40 MeOAc 0.2 2.9 47 19%
40 MEK/ 0 MIBK/40 t-BuOAc0.5 3.5 44 68%
0 MEKI40 MIBK/40 t-BuOAc0.9 6.2 48 17%
The results do show a marked effect in the evaporation profile
when MeOAc is substituted for MEK or MIBK, and thus this known low
OFP fluid would not be a good substitute for currently-used coating
fluids. While t-BuOAc shows a similar profile to DMC and MP, as
discussed above t-BuOAc is thermally unstable, and is not inert with
respect to acids, as shown below.
Examale 2
Acrylic solvent systems were prepared to test the stability of
dimethyl carbonate to acid catalysts, which are commonly present in
coating compositions. The formulations contained 29.9 wt% DMC,
28.7 wt% pentyl acetate, 20.2 wt% n-butyl acetate, 16.1 wt% n-butyl
alcohol, 3.6 wt% methyl ethyl ketone, 1.5 wt% isopropyl alcohol. 2 wt%
toluene as an internal standard. The latter materials were purchased
from Aldrich Chemical Co.
Para toluene sulfonic acid (pTSA) was added to the above
formulation (again, pTSA was purchased from Aldrich Chemical Co.), in
the amount of 0.5 wt%. The solutions were sealed and placed in an
oven at 50°C under a nitrogen atmosphere. Samples were withdrawn
at intervals for testing. The content of dimethyl carbonate was
monitored over time by gas chromatographic analysis using an HP
5890 gas chromatograph. In a parallel experiment an equal amount of
tert. Butyl acetate was used instead of DMC. The results are shown
below in Table 8 (all percentages are by weight).
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Table 3
Solvent Wt.% of SolventWt.% of Solvent Wt.% of Solvent
At At At
Start of One Week Three Week
Test
Decomposition Decomposition
Period Period
DMC wt.% 100 97.8 95.4
Tert. Butyl 100 54.4 17.2
Acetate*
* decomposes and acetic acid )
to isobut (51.7 wt.%
lene 48.3
wt.%)
It is interesting to note that the decomposition products of tert
butyl acetate, isobutylene and acetic acid, have MIRs of 6.81 and 0.67
respectively. This results in a weight average reactivity of the
decomposition products of tert. butyl acetate to be 3.64 grams of ozone
produced per gram of decomposition products versus 0.21 per tert
butyl acetate. Such decomposition products would not be considered
negligible or low reactivity compounds.
The above results clearly show that dimethyl carbonate is more
stable to acid catalysts than is t-butyl acetate. Thus, a coating
formulation containing dimethyl carbonate as a fluid would be expected
to be more storage stable than one containing t-butyl acetate. Storage
stability is an important attribute in a coating composition, e.g., a paint.
Example 3 (Comparative)
A typical acrylic-based coating system was prepared using a
Gloss White Electrostatic Spray Topcoat, formulation MKY-504-1
developed and recommended by S.C. Johnson Polymer as follows:
Johcryl 504 410.62 gr. (80% conc. in xylene)
CymeIT"" 303 \140.94 gr.
Ti02 (TiPure R-960) 360.68 gr.
Byk P-1049 2.22 gr.
10% DC-57 in MAK 11.10 gr.
Nacure 2500 5.55 gr.
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Amyl Acetate 78.8 gr.
Butyl Acetate 55.49 gr.
N-Butanol 44.39 gr.
This Composition had the following formula constraints:
Viscosity (Ford #4) 44 seconds
PVC 10.2%
Weight Solids 75%
Resistivity 0.7 megaohms
VOC 2.78 Ib./gal.
P/B Ratio 0.76
Volume Solids 61.7%
Catalyst Level 0.3% on TRS
The total solvent composition of the formulation was as follows:
Xylene 29.9 wt.
Amyl Acetate 28.7 wt.
Butyl Acetate 20.2 wt.
N-Butanol 16.1 wt.
MAK 3.6 wt.
I PA 1.5 wt.
Additional data was calculated for the formulation:
Surface Tension .25°C 27.12 dyn/cm
Flash Point: Deg. C 19.5 (Deg. F 67.1 )
The calculated Evaporation Profile for the formulation
characterized in minutes for portions of solvents as it evaporates was
as follows:
10% 50% 80%
90%
Time (min.) 4.7 33 90 160
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This composition was a base to demonstrate how substitution of
different component of solvent composition would effect VOC, ozone
formation, flash point, and evaporation profile. To calculate ozone
formation (in Ibs. of ozone per gallon of solid coatings), the following
5 Absolute MIR values from published sources referenced above and our
data for the solvents suggested in the present invention were used:
Component Absolute MIR
Xylene 7.81
N-Butyl Alcohol 3.53
10 N-Butyl Acetate 1.14
Amyl Acetate 1.16
Isopropyl Alcohol (IPA) 0.81
Methyl Amyl Ketone (MAK) 2.65
Wt. Average Absolute MIR for the solvent composition above
15 was calculated to be 3.57 Ibs. ozone per Ib. of solvent composition, or,
multiplying by VOC = 2.78 Ib./gal. equates to 9.935 Ibs. of ozone per
gal. of paint.
Example 3a. - Using the same control formulation as in Example 3
20 above, dimethyl carbonate was substituted for the xylene in the
formulation. The replacement solvent composition was as follows:
DMC 29.9 wt.
Amyl Acetate 28.7 wt.
Butyl Acetate 20.2 wt.
25 N-Butanol 16.1 wt.
MAK 3.6 wt.
I PA 1.5 wt.
As a Negligibly Polluting Potential Fluid solvent, DMC can be
removed from VOC, providing 29.9% VOC reduction calculated to be
30 1.95 Ib/gal - a very strong VOC reduction which would be difficult to
achieve by conventional reformulation.
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The surface tension, flash point, and evaporation profile were
calculated to be:
Surface Tension 27.71 dyn/cm
Flash Point: Deg. C 23.2 (Deg. F 73.8)
Evaporation Profile:
10% 50% 80%
90%
Time (min.) 3.8 29 100 190
As seen from the data, the substitution of xylene with DMC did
not alter the Evaporation Profile significantly and improved (by raising)
the Flash Point. Applying to the solvent composition, the Absolute MIR
reactivity from Table 2b Absolute MIR DMC = 0.079, the Wt. Avg. MIR
reactivity for the solvent composition was calculated to be 1.245, or,
multiplying by VOC = 2.78 Ib./gal. equates to 3.52 Ibs. of ozone per gal.
of solid coating.
This represents a 65% reduction in ozone formation as
compared with control composition.
The data demonstrates that the reactivity approach with the use
of solvents suggested in the present invention provide possibility to
achieve tremendous reduction in ozone formation, incomparably
stronger than would be expected from the simple VOC reduction and
without any negative effect on the properties of the coating
composition.
Example 3b. Using the same control formulation as in Example 3
above, methyl pivalate (MP) was substituted for the xylene in the
formulation. The replacement solvent composition was as follows:
M P 29. 9 wt.
Amyl Acetate 28.7 wt.
Butyl Acetate 20.2 wt.
N-Butanol 16.1 wt.
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98602~P~T
MAK 3.6 wt.
1 PA '1. 5 wt.
The hlegligibly Polluting Potential Fluid solvent MP can be rel'rnoved
from VOC, providing Z9.9% VClC reduction to VC1C = 1.95 tb~gal. -~ very
stro~r~g VAC reduction which would be difficult to achieve by conventional
reformulation_
The surface ten~ia~n, flash point, and evaporation profile were
calculated fo be:
Surface Tension 26 dynlcm
Flash Point I~eg. C 19.7 (deg. F fi7.5)
Evaporation Profile:
'1C1°~° 50°~0 8~% 9U%
Tlme (min,) ~.3 ~8 ~0 175
As seen from the data, substitution of xylene with MP did not alter
the Evaporation Profile significantly rar pause any negative effect on the
properties of the composition.
Using the Absolute MtR reactivity from Table Via, the Wt. Avg. MIR
reactivity was calculated for the solvent composition to be '1.3'12.
Multiplying the Mlf~ by the VOC of 2.78 Iblgal, it is Calculated to be 3.~5
Ibs. rrf ozone per gal. of solid ooating or X3.3% reduction in ozone
formation as compared with control composition.
These examples demonstrate that both the compounds suggested
by the present invention unexpectedly provided rtt~t only a very significant
reduction in VQC in a typical eaating formulation, but also provided
incomparably stronger reduction in v~c~ne formation potential. These very
strong positive effects were achieved without any negative effect an the
coating compositions.
The value of Low Polluting Patentis~l Fluids (L~'PF), Very Low
Polluting Potential Fluids (VLPPF), and especially Negligibly Polluting
Potential Fluids (NPPF) of the present invention provide the opportunity
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for further strong reduction in ozone formation that can be achieved
even without a VOC reduction from the fluid solvent compositions.
The following examples demonstrate how Very Low Polluting
Potential Fluids (VLPPF) of the present invention can provide
significant additional reduction in ozone formation even without any
change in the,VOC value of the compositions. A significant reduction
in ozone formation can be provided by the use of diisopropyl carbonate
- one of Very Low Polluting Potential Fluids suggested in the present
invention which provide medium to low evaporation rate, and,
therefore, is an acceptable substitute for higher Absolute MIR value
conventional oxygenated solvents with a boiling temperature of 135°C -
160°C.
Example 3c. Using the same control formulation as in Example 3
above, the replacement solvent composition substituted DMC for the
xylene, DIPC for the MAK, and a partial substitution of Amyl Acetate
with DIPC.
Solvent Composition:
DMC 29.9 wt.
DIPC 23.8 wt.
Amyl Acetate 8.5 wt.
Butyl Acetate 20.2 wt.
N-Butanol 16.1 wt.
I PA 1.5 wt.
This composition can provide the same strong VOC reduction as
in Example 3a (VOC = 1.95 Ib/gal instead of 2.78 Ib/gal).
The surface tension, flash paint, and evaporation profile were
calculated to be:
Surface Tension 28.69 dyn/cm
Flash Point: Deg. C 39.9 (Deg. F 103.8)
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Evaporation Profile:
10% 50% 80%
90%
Time (min.) 4.0 30 105 205
The data demonstrates an insignificant change in the
Evaporation Profile and no negative effects on the properties of the
composition.
Applying this solvent composition, the Absolute MIR reactivities
from the above referenced materials given above, we find Wt. Avg.
Absolute MIR for the solvent composition = 1.0785, or, multiplying by
the VOC = 2.78 Ib/gal we find 2.998 Ibs. of ozone per gal. of coating.
This would represent 69.8% reduction in ozone formation as
compared with control composition. This additional reduction of ozone
formation is actually achieved at the same VOC and demonstrates the
potential to achieve significant ozone reduction within the same level of
VOC and without any negative effect on coating composition
properties.
Example 3d. Using the same control formulation as in Example 3
above, the replacement solvent composition substituted MP for the
xylene, DIPC for the MAK, and a partial substitution of Amyl Acetate
with DIPC.
Solvent Composition:
M P 29.9 wt.
DIPC 23.8 wt.
Amyl Acetate 8.5 wt.
Butyl Acetate 20.2 wt.
N-Butanol 16.1 wt.
I PA 1.5 wt.
The VOC reduction for the composition would be the same as in
Examples 3a-3c to 1.95.
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The surface tension, flash point, and evaporation profile were
calculated to be:
Surface Tension 27.16 dyn/cm
Flash Point: Deg. C 35.5 (Deg. F 95.9)
5 Evaporation Profile:
10% 50% 80%
90%
Time (min.) 4.0 32 100 195
The data demonstrates insignificant change in the Evaporation
10 Profile and no negative effects on the properties of the composition.
Applying to the solvent composition the Absolute MIR reactivity
as Wt. Avg. Absolute MIR for the solvent composition of 1.125, or,
multiplying by the VOC = 2.78 Ib/gal results in an MIR value of 3.23 Ibs.
of ozone per gal. of coating, or 67.5% reduction in ozone formation as
15 compared with control composition. Comparing this with Example 3c,
63.3% reduction in ozone formation, we observe a significant reduction
at the same VOC.
Examples 3c and 3d demonstrate important opportunities to
reduce ozone formation through the substitution of high reactivity
20 conventional components of the solvent (fluid) composition exclusively
with the Negligibly Polluting Potential and Very Low Polluting Potential
fluids from the present invention.
However, an important objective of the present invention is the
combinations with other known Low Polluting Potential or Very Low
25 Polluting Potential fluid solvents with Negligibly Polluting Potential,
Very
Low Polluting Potential, or Low Polluting Potential fluid solvents of the
present invention.
These combinations can provide the additional reduction in
ozone formation potential unattainable by a currently known
30 technology.
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Analyses of the compositions of Examples 3c and 3d shows that
these contain N-Butanol with Absolute MIR = 3.53.
This alcohol is necessary to provide storage stability of the
compositions containing hexamethoxymethylmelamine (HMMM)
crosslinking agents (CymeITM 303) and acid (or blocked acid) catalysts.
This material cannot be effectively substituted with a non-hydroxyl
bearing solvent.
To provide further reduction in ozone formation for the solvent
compositions comprising C4 and higher alcohols and ether alcohols,
the alcohol functional components can be substituted with methanol
and or isopropanol. These hydroxyl functional components have very
low reactivity in atmospheric photochemical ozone formation. Due to
the toxicity concerns regarding methanol, the preferred choice is
isopropanol. The quantity of the alcohols can vary and needs to be
optimized for specific formulations, however, mole per mole ratio can
be used as a starting point for optimization.
The following Examples 3e and 3f, demonstrate the
effectiveness of the combinations to achieve a very high reduction in
ozone formation by the combinations of the present invention.
Example 3e. Using the same control formulation as in Example 3
above, the replacement solvent composition substituted DMC for the
xylene, DIPC for the MAIL, a partial substitution of Amyl Acetate with
DIPC, and IPA for the N-Butanol.
Solvent Composition:
DMC 29.9 wt.
DIPC 23.8 wt.
Amyl Acetate 11.5 wt.
Butyl Acetate 20.2 wt.
I PA 14.6 wt.
In selection of different components, 1:1 mole ratio of N-Butanol
was substituted with the isopropanol. The weight reduction due to
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lower molecular weight of IPA versus N-Butanol was compensated by
increasing in amyl acetate to compensate for the initial increase in
evaporation rate. As in all examples of the series, the VOC is reduced
from 2.78 Ib/gal. to 1.95 Ib/gal.
The surface tension, flash point, and evaporation profile were
calculated to be:
Surface Tension 28.73 dyn/cm
Flash Point: Deg. C 38.4 (Deg. F 101.1 )
Evaporation Profile:
10% 50% 80% 90%
Time (min.) 2.6 25 112 215
The data demonstrates insignificant change in the Evaporation
Profile and no negative effects on the properties of the composition.
The Wt. Avg. Absolute MIR for the solvent composition is 0.650,
or, multiplying by the VOC = 2.78, we find 1.81 Ibs. of ozone per gal. of
coating. This represents an 81.2% reduction in ozone formation as
compared with control composition.
Comparing Examples 3a, 3c, 3e, shows how proper selection of
the components of the fluid (solvent) composition can provide a very
strong reduction in VOC for the overall solvent compositions. Even
more important, the examples demonstrate tremendous difference in
ozone formation potential even at the same VOC.
Example 3f. Using the same control formulation as in Example 3
above, the replacement solvent composition substituted MP for the
xylene, DIPC for the MAIL, a partial substitution of Amyl Acetate with
DIPC, and IPA for the N-Butanol.
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Solvent Composition:
MP 29.9 wt.
DIPC 23.8 wt.
Amyl Acetate 11.5 wt.
Butyl Acetate 20.2 wt.
I PA 14.6 wt.
The VOC for the composition is 1.95.
The surface tension, flash point, and evaporation profile were
calculated to be:
Surface Tension. 27.02 dyn/cm
Flash Point: Deg. C 34.1 (Deg. F 93.4)
Evaporation Profile:
10% 50% 80%
90%
Time (min.) 2.3 22 100 195
The data also demonstrates acceptable Evaporation Profile and
overall good properties for the coating composition.
The WtAv AMIR for the composition is 0.697 or 0.697 X 2.78 = 1.938
Ibs. of ozone per gal. of paint. This would represent 80.5% reduction in
ozone formation as compared with control composition.
Example 3a. Using the same control formulation as in Example 3
above, the replacement solvent composition substituted acetone, a
solvent having an MIR similar to the Negligibly Polluting' Potential
Fluids of the present invention, for the xylene.
Solvent Composition:
Acetone 29.9 wt.
Amyl Acetate 28.7 wt.
Butyl Acetate 20.2 wt.
N-Butanol 16.1 wt.
MAK 3.6 wt.
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I PA 1.5 wt.
The surface tension, flash point, and evaporation profile were
calculated to be:
Surface Tension 25.76 dyn/cm
Flash Point: Deg. C 11.1 (Deg. F 52.0)
Evaporation Profile:
10% 50% 80% 90%
Time (min.) 1.1 18 83 164
The data demonstrates an unacceptable flash point reduction and a
very fast evaporation rate, up to 50% of evaporation, which makes the
solvent composition unacceptable for commercial applications. The
VOC of the coating composition is 1.95 Ib/gal., which is the same as
Examples 3a-3f, but the flash point and evaporation rate prevent the
use of the acetone as an acceptable Negligibly Polluting Potential Fluid
of the present invention in an industrial application.
Example 4
A cold-cleaning solvent comprising about 10-60 wt%
fluorocarbon, about 1-30 wt% of a chlorinated solvent, and about 10-40
wt% of an oxygenated organic solvent is disclosed in U.S. 5,552,080.
The oxygenated organic solvent is preferably n-butanol or isopropanol,
but may be also selected from numerous other oxygenated organic
fluids, including DMC.
The present inventors have surprisingly discovered that fluids
from to the present invention may be used in the aforementioned
cleaning composition to reduce tropospheric ozone formation, which is
the opposite phenomenon from ozone depletion. This is completely
unexpected.
Moreover, contrary to the disclosure by the inventors of the
above-mentioned patent, DMC is superior to any of the solvents listed,
in terms of reduced ozone formation. That is, replacing n-butanol (MIR
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.3.6) entirely with DMC (MIR = .079) results in a huge decrease in the
overall weighted average of the blend. Likewise, the present invention
also contemplate a blend of, for instance, 50/50 n-butanol/DMC or
50/50 n-butanol/MP, along with the halocarbons, as a cold cleaning
5 solvent useful in reducing ground-based ozone formation. This is a
second unexpected result provided by the present invention. Similar
results can be expected using methyl pivalate and the other fluids
according to the present invention, without a loss of cleaning efficacy.
The inventors of the present invention have discovered that blends of
10 dimethyl carbonate and methyl pivalate in a wide range of
concentrations can be used as a cold-cleaning solvent composition.
The ratios of DMC to MP from 9:1 to 1:9 would allow for a wide range
of Negligibly Polluting Potential Fluid solvents with acceptable
application properties. These compositions could therefore provide the
15 base for non VOC cleaning fluids without halogenated components and
with reasonably high flash points (around 20 - 25 °C). Other solvents
could certainly be incorporated into these compositions allowing for the
modification of the evaporation profile as desired, preferably from a
Low Polluting Potential Fluid, a Very Low Polluting Potential Fluid, or a
20 Negligibly Polluting Potential Fluid of the present inventions.
Example 5
The delivery of seed coatings including insecticides and other
pesticides, and agents attenuating the growth of plants (e.g.,
25 hormones) is extremely valuable to the agricultural industry. In addition
to traditional coating techniques, the OSIT method (Organic Solvent
Infusion Technique) has been studied and may be useful in the
germination of hard coated seeds. In this method, the seed is soaked
in the solvent for a fixed amount of time. The solvents are generally
30 highly volatile solvents such as xylene, acetone, methylene chloride
(CH2C12). This technique has also been studied in the context of
translocation experiments for the production of transgenic crops.
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The substitution of DMC and MP for MEK results in a similar
evaporation profile, while greatly reducing the MIR of the fluid used, in
the case of xylene (p-xylene has the lowest MIR of the xylenes, at MIR
= 4.40) and acetone (MIR = 0.48), and having a reduced toxicity in the
case of CH2C12 (MIR = 0.10).
The examples presented herein demonstrate several beneficial aspects
of the inventions:
(a) Fluids with negligibly low MIR reactivity values (< 0.5 gr
ozone produced/gr solvent fluid used) can be produced using specific
chemical compounds (as it demonstrated in literature and in the
present invention) and by proper blending with extremely low MIR
reactivity organic compounds, preferably methyl acetate and, especially
DMC. The blends not only significantly expand the range of negligibly
reactive compounds, but also expand the range of properties, and,
especially, evaporation profile, which is always significantly wider for
blends, than for individual compounds. This is a principal advantage of
blends that are deemed Negligibly Polluting Potential Fluids.
(b) The use of Negligibly Polluting Potential Fluids of the
present invention provide potential for very significant VOC reduction of
the typical solvent compositions. However, reduction of ozone
formation with the substitution a part of any solvent with the Negligibly
Polluting Potential Fluids of the present invention is disproportionately
greater than VOC reduction (~65% versus ~30%). The data
demonstrate that VOC is a very poor indicator of ozone formation and
can provide misleading data concerning actual ozone formation.
(c) The use of Negligibly Polluting Potential Fluids or any
exempt solvents, even with highly beneficial compounds of the present
invention provides significant, but still limited reduction in ozone
formation.
Further, the use of Low Polluting Potential Fluids and,
especially, Very Low Polluting Potential Fluids in solvent fluids as
described herein additionally provides very significant reduction in
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ozone formation which can not be, achieved when the use of Negligibly
- .
Polluting Potential Fluids is limited by their properties. It should be also
said, that use of Very Low Polluting Potential Fluids alone cannot also
provide tt~,e maximum reduction in ozone formation.
However, synergistic effects providing the best reduction in
ozone formation can be achieved by combining properly selected Low
Polluting Potential Fluids, Very Low Polluting Potential Fluids, and
Negligibly Polluting Potential Fluids. This conclusion is not limited to
the specific structures of LPPF, VLPPF, and NPPF discovered by the
inventors of the present invention, but also achievable with the known
in the art LPPF, VLPPF, and NPPF.
As seen from examples, the use of NPPF provided ozone
formation reduction to 63-65%. Addition of very low reactivity fluids
provided additional reduction to 80-81 % as demonstrated in the
examples.
These results were achieved without additional VOC reduction
which demonstrate that VOC does not correlate with ozone formation.
Additionally, there is a tremendous potential in using the present
invention to achieve very significant environmental benefits.
The invention has now been described in detail, and it is to be
understood that the ordinary artisan in possession of the present
disclosure could practice the invention, within the spirit and scope of
the appended claims, other than as specifically set forth. Hence, it will
be appreciated that many variations of the following preferred
embodiments can be practiced.
A first preferred embodiment, which is a composition, optionally
suitable for a coatings application, comprising at least one fluid,
preferably an organic fluid, more preferably a liquid organic fluid, still
more preferably a liquid organic fluid which is an oxygenated
hydrocarbon, said fluid having a low MIR, preferably similar to or lower
than that of acetone and more preferably less than that of ethane.
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Even more preferably also having at least one or more of the
following attributes: satisfying at least one of the flash point criterion set
forth herein or otherwise having a low flammability, low formation of
particulates having a diameter of 2.5 pm or less, as described in more
detail above, suitable evaporation rates and solvency that will be useful
in a wide range of industrial applications, such as by dispersing,
solvating, acting as a carrier, diluent, and the Like, low toxicity such
that LD50 satisfies the criteria as otherwise described herein, high
thermal stability, and inertness to reaction in solution, particularly to
acid or base catalyzed reactions.
Still more preferably wherein the composition comprises,
includes, consists or consists essentially of a fluid selected from:
dialkyl carbonates, such as dimethyl carbonate (DMC), methyl
ethyl carbonate, methyl isopropyl carbonate, methyl sec-butyl
carbonate, methyl t-butyl carbonate, methyl neopentyl carbonate, and
diisopropyl carbonate;
alkyl acetates, such as neopentyl acetate, ethylene glycol
diacetate, 1,2-propylene glycol diacetate, 1,3-propylene glycol
diacetate, 1,2-butylene glycol diacetate, 1,3-butylene glycol diacetate,
2,3-butylene glycol diacetate, neopentyl glycol diacetate;
dioxolanes such as 2,2-dimethyl dioxolane, 2,2,4-trimethyl
dioxolane, 2,2,4,5-tetra methyl dioxolane;
pivalates such as methyl pivalate, isopropyl pivalate, t-butyl
pivalate (TBP), neopentyl pivalate (NPP), 1,2-propylene glycol bis
pivalate (PGBP), ethylene glycol bis-pivalate, ethylene glycol
monopivalate, 1,2-butylene glycol mono-pivalate (1,2-BGMP), 2,3-
butylene glycol monopivalate (2,3-BGMP), 1,2-butylene glycol pivalate
acetate (1,2-BGPA), 1,2-butylene glycol pivalate acetate (1,2-BGPA),
2,3-butylene glycol pivalate acetate (2,3-BGPA), ethylene glycol
pivalate acetate, 1,2 propylene glycol monopivalate, neopentyl glycol
mono pivalate, and 1,2-propylene glycol pivalate acetate;
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isobutyrate compounds such as isopropyl isobutyrate, neopentyl
isobutyrate, and neopentyl glycol mono isobutyrate;
propionate compounds such as methyl propionate, ethyl
propionate, isopropyl propionate and n-propyl propionate; and
2,2,4,4-tetramethyl pentanonitrile (TMPN); isopropyl
neononanoate; pivalonitrile; methyl 2,2,4,4-tetramethyl pentanoate
(methyl neononanoate); and methyl 3,5,5 trimethyl hexanoate.
Preferably wherein the composition is used in a stationary, non-
combustion process, on an industrial scale, said composition also
including a second fluid, wherein the second fluid has a high MIR,
greater than that of acetone, and more preferably an MIR scale of
>1.00; and even more preferably wherein the composition further
includes at least one resin and yet still more preferably wherein the
composition further comprises a pigment.
Also a composition suitable for coating a substrate, comprising
one of the aforementioned fluids having a low MIR in the first
embodiment above, preferably dimethyl carbonate, methyl pivalate, t-
butyl pivalate, or a mixture thereof, and at least one solute, wherein
the solute is preferably selected from the group consisting of resins,
pigments, and mixtures thereof; and optionally also wherein the
composition does not contain a halocarbon, more preferably wherein
the composition contains less than 1000 ppm of any chlorocarbon or
bromocarbon; and also optionally wherein the composition is not used
in a combustion process, and also optionally wherein the fluid has at
least one of the following attributes:
i) an MIR equal to or less than 1.5 gr of ozone produced/gr of
fluid solvent;
ii) a flash point of at least -6.1 °C, or the even more preferable
flash points set forth herein above;
iii) a toxicity level wherein oral rat LD50 is better than at least
500 mg/kg (i.e. greater than 1000 mg/kg, or more preferably greater
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than 2000 mg/kg), or the even more preferable toxicity levels set forth
above;
iv) a low formation of particulates less than 2.5 pm, where "low
formation" is defined as less than 65 micrograms per cubic meter
5 measured over a 24 hour period or more preferably less than 50
micrograms per cubic meter, measure over the same period; and
v) an evaporation rate up to12 relative to normal butyl acetate.
Even more particularly, wherein DMC or methyl pivalate or the
mixture thereof is present in an amount sufficient to bring the weight
10 average MIR of a composition to below 1.50 and more preferably
below 1.00, yet still more preferably below 0.50, still even more
preferably below 0.31, and in another embodiment wherein the amount
of DMC or methyl pivalate is at least 10 percent by volume, more
preferably in the amount of more than 25 percent by volume, still more
15 preferably in the amount of at least 50 percent by volume of the organic
liquid in the composition, and most preferably wherein the fluid is a
paint mixture containing a pigment, or mixture thereof.
Or, more particularly, this preferred embodiment relates to a
non-combustion process utilizing a process fluid comprising a first fluid
20 wherein at least some of the first fluid evaporates into the atmosphere,
the improvement comprising replacing at least a portion the first fluid
with a second fluid selected from dimethyl carbonate, methyl pivalate,
or a mixture thereof, thereby decreasing ozone formation from
atmospheric photochemical reactions; and also more preferable
25 embodiments including: where the process fluid acts as a solvent,
carrier, diluent, surface tension modifier, or any combination thereof, in
the process; where the process fluid does not contain a halocarbon;
where the decreasing ozone formation is based on a calculation using
an MIR scale; where the process is a stationary industrial process;
30 where the replacing results in at least one of the following
improvements:
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i) an MIR at least 10% less than the MIR of the process fluid
prior to the replacing;
ii) the flash point or a weighted average flash point of the
process fluid increasing to above -6.1 °C;
iii) a reduced toxicity level of the process fluid to greater than at
least 2000 mg/kg;
iv) a measureable decrease in the formation of particulates
having a diameter less than 2.5 pm produced by the process;
v) a change in the evaporation rate of the process fluid into the
range of less than12 relative to normal butyl acetate; and
vi) a decrease in the decomposition of the process fluid based
on reactions with acid catalysts present in the fluid; or where at least
two and more preferably three, or even more preferably four, or still
more preferably five and most preferably six of these properties are
improved; where the replacing results in a blend of fluids, and wherein
the blend has a flash point of at least greater than 15°C; or where the
blend has a flash point of at least greater than 60°C; or where the
replacing results in a reduction in the MIR of the process fluid by at
least 10%; or where the reduction is at least 25%; or where the
reduction is at least 50%; or where the process is a coating process
comprising coating a substrate with a composition comprising at least
one fluid which is intended to evaporate; and where the process
provides a painted surface; where the first fluid is selected from at least
one of toluene; xylenes, ethanol, n-butanol, n-pentanol, sec-butanol,
propylene glycol methyl ether acetate, methyl isobutyl ketone, C5-C10
linear ketones, cyclic ketones, halocarbons, methyl t-butyl ether;
mineral spirits; and especially where the second fluid is DMC, MP, or a
mixture thereof; and finally where the first fluid replaced has an
evaporative rate ranging from that of MEK to that of n-butyl acetate,
and after the replacing the process fluid has an evaporative rate
ranging from that of MEIC to that of n-butyl acetate.
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A second preferred embodiment is a method of selecting a fluid
system used in an industrial process or for a composition manufactured
by an industrial process, comprising selecting at least one fluid having
a low OFP as set forth above in the first preferred embodiment, either
specifically, e.g., as in DMC, or generally, e.g., with reference to ozone
formation, MIR, and the like, preferably having an M1R<1.00, , more
preferably <0.50, still more preferably <0.35, and most preferably
<0.24;
and also a second fluid, not having a low OFP, preferably having
an MIR>1.00, or in an embodiment selected from hydrocarbon fluids
such as toluene and xylenes; alcohols such as methanol, isopropyl
alcohol, diacetone alcohol, and sec-butanol; esters such as ethyl
acetate, propyl acetate, butyl acetate, isobutyl isobutyrate, isoamyl
isobutyrate, propylene glycol methyl ether acetate; ketones such as
methyl ethyl ketone (MEK), linear ketones, preferably C5-Coo linear
ketone, cyclic ketones; halocarbons, particularly chlorinated
hydrocarbons; and methyl t-butyl ether (MTBE);
and wherein the selection is made so that the weight average
OFP, based on any OFP scale but preferably based on the MIR scale,
is equal to or less than that of acetone and even more preferably equal
to or less than that of ethane, and when measured by the MIR scale is
less than or equal to the preferred MIR of the blends set forth above
(e.g., weight average MIR<1.00, etc), and even more preferably
wherein the blend has at least one of the aforementioned performance
attributes, andlor especially wherein at least one of the following
criterion renders the blend superior, in that criterion, to such a
composition without a fluid according to the present invention: e.g.;
blend flash point or weighted average flash point, solvency, formation
of 2.5PM, evaporation rate, toxicity, thermal stability, and inertness.
Finally, but not in the least, there is the third preferred
embodiment of an improved industrial process which uses a fluid, the
improvement comprising decreasing the contribution of the process to
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ground-based ozone formation by substituting for at least a portion of
the fluid used a fluid according to the present invention, and preferably
selected from any one or more of the low MIR fluids set forth in the first
embodiment above, and even more preferred wherein the final fluid
used in the process is a blend as set forth in the second preferred
embodiment, and particularly wherein the process is one set forth
herein and even more preferably wherein the process is a coating
process, an extraction process, a drilling process, or the process is one
used to produce a consumer product, such as a pharmaceutical or
cosmetic, and preferably wherein the decrease in contribution of the
process to ground-based ozone formation is such that the MIR of the
process fluid, whether it be a single fluid or blend, decreases from
>1.50 to less than or equal to 1.50, more preferably from >1.50 to less
than or equal to 1.00, even more preferably from >1.50 to less than or
equal to 0.50, and so on as set forth above. In this embodiment, it is
preferred that at least one of the previously recited performance
properties be absent in the initial fluid and present in the final fluid.
The embodiments described hereinbefore are the subject of the
following claims. One such embodiment relates to a non-combustion,
industrial process utilizing a process fluid acting as any one or more of
solvent, carrier, diluent, and surface tension modifier, wherein the
process fluid comprises a compound selected from the group specified
in claim 1. According to a related embodiment, in a non-combustion
process utilizing a process fluid comprising a first fluid wherein at least
some of the first fluid evaporates into the atmosphere, there is provided
the improvement comprising replacing at least a portion of the first fluid
with a second fluid selected from the compounds and mixtures
specified in claim 2.
A further embodiment relates to the use, in a fluid system for
employment in an industrial non-combustion process that comprises
evaporation of at least a part of the system into the atmosphere, of a
fluid F to confer on the system properties comprising:
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a. an ozone formation potential (OFP) that is lower than that
of the system without fluid F; and
b. at least one of the following:
i) a flash point that is higher than that of the system
without fluid F;
ii) a toxicity level that is higher (less toxic) than that of
the system without fluid F
iii) a formation of particulates having a diameter less
than 2.5um (microns) at a density (when measured over
a 24-hour period) that is lower than that of the system
without fluid F;
iv) an evaporative rate in the range of 0.1 to 12 relative
to n-butyl acetate; and
v) a decomposition tendency in the presence of acid
catalyst that is lower than that of the system without fluid
F,
the fluid F being a volatile organic compound containing an oxygen
moiety and being substantially free from moieties containing
unsaturated carbon-carbon bonds or aromatic groups, and being
selected from carbonates, acetates, pivalates, isobutyrates,
pentanoates, hexanoates, nonanoates and nitrites.
Preferably the fluid F has an OFP (measured on the Absolute
MIR scale in units of g. ozone/g. fluid ) of (1 ) <_ 1.5 or (2) <_ 1.0 or (3)
<_
0.5 andlor the OFP of the fluid system resulting from use of fluid F has
an OFP (Absolute MIR scale in units of g. ozone/g. system) of (1 ) <_ 1.5
or (2) _< 1.0 or (3) <_ 0.5.
The resulting fluid system preferably comprises from (1 ) 10 to 90
wt. % or (2) 20 to 80 wt. % or (3) 25 to 75 wt. % of fluid F.
Preferably the property (b) conferred on the system is selected
from:
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i) a flash point that is (1 ) above - 6.1 °C or (2) above 15°C
or
(3) above 38°C or (4) above 60°C;
ii) a toxicity level that is (on the oral rate LD 50 scale in units
of mg/kg) (1 ) > 500 or (2) > 1000 or (3) > 2000 or (4) > 3000 or
5 (5) > 5000;
iii) a formation of particulates having a diameter less that 2.5
um (microns) at a density (when measured over a 24-hour
period) that is (1 ) below 65 mg/m3 or (2) below 50 mg/m3; and
iv) an evaporative rate relative to that of n-butyl acetate in the
10 range of (1 ) 5-3 or (2) 3-2 or (3) 2-1 or (4) 1.0-0.3 or (5) 0.3-0.1.
More than one fluid F may be used. Examples of the industrial
process (e.g., one using more than 500 kg of fluid system per year)
include coating applications, cleaning applications, extraction
processes, application of agricultural chemicals, printing ink
15 applications, tackification processes, heat-transfer processes or
dissolution processes. Such process may comprise evaporation into
the atmosphere of a proportion of the fluid system that is (1 ) >_ 10% or
(2) >_ 20% or (3) >_ 50% or (4) >_ 75% or (5) >_ 90% or (6) >_ 99%.
In a preferred embodiment, fluid F is a compound the
20 hydrocarbyl moieties of which are selected from methyl and/or ethyl
and/or isopropyl. In another preferred embodiment, fluid F comprises
hydrocarbyl moieties which have, collectively, a ratio of methyl
hydrogens to non-methyl hydrogens that is (1 ) greater than 1, or (2)
greater than 5 or (3) greater than or equal to 9.
25 Yet another embodiment concerns an industrial formulation-fluid
system comprising one or more organic volatile formulation-fluids
including a fluid F being a compound containing an oxygen moiety and
being substantially free from moieties containing unsaturated carbon-
carbon bonds or aromatic groups, the fluid F being selected from the
30 group consisting of carbonates, acetates, pivalates, isobutyrates,
propionates, pentanoates, hexanoates, nonanoates, nitrites and
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mixtures of any two or more thereof, which fluid F has an ozone
formation potential (OFP) (in accordance with the Absolute MIR scale
in units of g. ozone/g. fluid F) of <_ 1.5 and is present in an amount such
that the formulation-fluid system has an OFP that is at least 10% less
than that of the formulation-fluid system without fluid F. Preferably the
amount of fluid F is such that the OFP of the system is (1 ) at least 25%
or (2) at least 50% of the OFP of the system without fluid F. It is
preferred that fluid F comprises hydrocarbyl moieties which have,
collectively, a ratio of methyl hydrogen to non-methyl hydrogen (1 )
greater than 1 or (2) greater than 5 or (3) greater than or equal to 9.
Propionates according to the present invention can be prepared
by converting ethylene to propionaldehyde via rhodium catalyzed
hydroformylation, and thereafter trimerizing the propionaldehyde via
two aldol condensations to form a C9 product which is hydrogenated to
the desired product, e.g., 2,4-dimethyl heptanol. Derivatives of
propionic acid (CH3CH2COOH) are readily made via conventional
esterification technology. Thus, reaction with methanol would provide
methyl propionate (CH3CH2COOCH3), with ethyl alcohol one obtains
ethyl propionate CH3CH2COOCH2CH3), with isopropyl alcohol one
obtains isopropyl propionate (CH3CH2COOCH[CH3]~), and with n-
propyl alcohol one obtains propyl Propionate
(CH3CH2COOCH2CH2CH3).
