Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
2 ~ 5 7
2456R-03
S Title: LIQUID COMPOSmONS CON r~INING CARBOXYLIC ESTERS
Cross-Reference to Related Applications
This is a continuation-in-part of U.S. Serial No. 07/728,441 filed July 11,
lg91, which is a continuation-in-part of U.S. Serial No. 608,600 filed on October 30,
1990, which is a continuation of Serial No. 343,087 filed on April 25, 1989 and now
abandoned, the disclosures of which are hereby incorporated in their entirety.
Field of the Invention
This invention relates to liquid compositions comprising at least one
fluoAne-containing hydrocarbon, and at least one lubricant. More particularly, the
invention relates to liquid compositions useful as refrigeration liquids.
Background of the Invention
Chlorofluorocarbons, generally referred to in the industry as CFCs, have been
widely used as propellants in aerosols, although use in aerosols has been diminishing
in recent years because of demands of environmentalists for the reduction if not a
complete ban on the use of CFCs because of the detrimental effect of CFCs on thestratosphere's ozone layer. CFCs also have been used because of their unique
combination of properties as refrigerants, foam-blowing agents, and specialty solvents
within the electronics and aerospace industries. Examples of CFCs which have been
utilized for these purposes include CFC-13 which is chlorotrifluoromethane, CFC-12
which is dichlorodifluoromethane, and CFC-l 13 which is
1,2,2-trifluoro- 1,1,2-trichloroethane.
Since 1976, when the aerosol industry began to feel the pressure to reduce if
not eliminate the use of CFCs, the aerosol industry has progressively moved toward
the substitution of hydrocarbon propellants for CFC propellants. The hydrocarbons,
such as butane, are readily available and inexpensive, and the quality of the final
-2-
product generally has been unaffected by the substitution of propellants. However,
the problem of finding a safe replacement of CFC refrigerants and foam-blowing
agents has been more difficult to solve. Several replacement candidates have been
sugges~ed as alternatives to the fully halogenated hydrocarbons, and these include
halogenated hydrocarbons containing at least some hydrogen atoms such as HCFC-?2which is difluorochloromethane, HCFC-123 which is 1, I -dichloro-
2,2,2-trifluoroethane, HFC-134a which is 1,1,1,2-tetrafluoroethaneand HCFC-141b
which is 1,l-dichloro-1-fluoroethane.
The owne depletion potential of these proposed substitutes is significantly lessthan the ozone depletion potential of the previously used CFCs. The owne depletion
potential is a relative measure of the capability of the material to destroy the ozone
layer in the atmosphere. It is a combination of the percentage by weight of chlorine
(the atom that attacks the owne molecule) and the lifetime in the atmosphere.
HCFC-22 and HFC-134a generally are recommended as being candidates in
refrigerant applications, and HFC-134a is particularly attractive because its ozone
depletion potential has been reported as being zero.
In order for any of the replacement materials to be useful as refrigerants, the
materials must be compatible with the lubricant utilized in the compressor. The
presently used refrigerants such as CFC-12 are readily compatible with mineral
lubricating oils which are utilized as the lubricant in air-conditioner compressors.
The above-described refrigerant candidates, however, have different solubility
characteristics than the refrigerants presently in use. For example, mineral lub-
ricating oil is incompatible (i.e., insoluble) with HI~C-134a. Such incompatibility
results in unacceptable compressor life in compression-type refrigeration equipment
including refrigeMtors and air-conditioners including auto, home, commercial, and
industrial air-conditioners.
In order to perform as a satisfactory refrigeration liquid, the mixture of
refrigerant and lubricant must be compatible and stable over a wide temperature range
such as from about 0C and above 80~C or above. For some uses, it is generally
desirable for the lubricants to be soluble in the refrigerant at concentrations
-3- 2 ~ 7
corresponding to the ratios customary in the environment of use, e.g. about S to 15 %,
over a temperature range from -30, or preferably ~0C, or below, to 80C or
above. In addition to therrnal stability, the refrigeration liquids must have acceptable
viscosity characteristics which are retained even at high temperatures, and the
S refrigeration liquid should not have a detrimental effect on materials used as seals in
the compressors.
Compositions comprising a tetrafluoroethane and polyoxyalkylene glycols are
discussed in U.S. Patent 4,755,316. The compositions are useful in refrigerationsystems. Refrigeration oils are described in U.S. Patents 4,248,726 and 4,267,064
10 which comprise mixtures of a polyglycol and 0.1 to 10% of glycidyl ether type epoxy
compounds, or epoxidized fatty acid monoesters, and optionally, epoxidized vegetable
oil. The lubricating oils are reported to be useful in refrigerators using a
halogen-containing refrigerant such as Freons 11, 12, 13, 22, 113, 114, 500 and 502
(available from DuPont), and in particular with Freon 12 or 22.
U.S. Patent 4,431,557 describes fluid compositions comprised of a fluoro- and
chloro-containing refrigerant, a hydrocarbon oil, and an alkylene oxide additivecompound which improves the thermal resistance of the oil in the presence of therefrigerant. Examples of hydrocarbon oils include mineral oil, alkyl benzene oil,
dibasic acid ester oil, polyglycols, etc. The composition may contain other additives
including load-carrying additives such as phosphorus acid esters, phosphoric acid
esters, etc. Examples of fluorocarbon refrigerants include R-l l, R-12, R-113, R-114,
R-S00, etc.
U.S. Patent 4,428,854 describes ahsorption refrigerant compositions for use
in refrigeration systems comprising 1,1,1,2-tetrafluoroethane and an organic solvent
capable of dissolving the ethane. Among the solvents disclosed are organic amides,
acetonitrile, N-methyl pyrroles, N-methyl pyrrolidine, N-methyl-2-pyrrolidone,
nitromethane, various dioxane derivatives, glycol ethers, butyl formate, butyl acetate,
diethyl oxalate, diethyl malonate, acetone, methyl ethyl ketone, other ketones and
aldehydes, triethyl phosphoric triamide, triethylene phosphate, triethyl phosphate, etc.
~'18~
Stabilized absorption compositions comprising (a) a halogenated hydrocarbon
refrigerant, (b) a liquid absorbent of a polyethylene glycol methyl ether, and (c) at
least one stabilizer are described in U.S. Patent 4,454,052. E~a nples of stabilizers
include phosphate esters, epoxy compounds, and organotin compounds. The
polyethylene glycol methyl ether-type compounds are of the general formula
CH3-O-(CH2H40)DR
wherein n is an integer of 1 to 6, and R is H, CH3- or CH3CO-. A variety of
halogenated hydrocarbons are described including 1,1-difluoromethane, 1,1,1 ,2-tetra-
fluoroethane, etc.
U.S. Patent 4,559,154 relates to absorption heat pumps utilizing as working
fluid, a saturated fluorohydrocarbon or fluorohydrocarbon ether having from 3 to 5
carbon atoms. Solvents reported to be useful with such fluorohydrocarbons include
ethers such as tetraglyme, amides which can be lactams such as the N-alkyl
pyrrolidones, sulfonamides and ureas including cyclic ureas.
Summary ~f he InvenLion
This invention relates to a liquid composition comprising (A) at least one
fluorine-containing hydrocarbon containing one to three carbon atoms, and a lubricant
comprising (B) at least one ester lubricant selected from the group consisting of (i)
an ester of a polyhydroxy compound and a monocarboxylic acylating agent having
from about 4 to about 15 carbon atoms, and (ii) an ester of polyhydroxy compoundand a combination of a dicarboxylic acylating agent and a monocarboxylic acylating
agent having about 7 to about 15 carbon atoms, and (C) at least one additive seluted
from the group consisting of an alkyl phosphite, an alkyl phosphonic acid ester, a
nitrogen-containing heterocycle, and a mixture thereof.
In another aspect, the invention relates to a liquid composition comprising (A)
a major amount of at least one fluorine-containing hydrocarbon containing 1 or 2carbon atoms; (B) a minor amount of at least one soluble organic lubricant comprising
2 ~ 7
at least one carboxylic ester of a polyhydroxy compound containing at least 2 hydroxy
groups and characterized by the general formula
R[OC(O)Rl]n a)
wherein R is a hydrocarbyl group, each Rl is independently hydro~en, a straight
chain lower hydro~arbyl group, a branched chain hydrocarbyl group, or a straightchain hydrocarbyl group containing from 8 to about 22 carbon atoms provided thatat least one Rl group is hydrogen, a lower straight chain hydrocarbyl or a branched
10 chain hydrocarbyl group, or a carboxylic acid- or carboxylic acid ester-containing
hydrocarbyl group, and n is at least 2; and (C) a phosphite.
In another aspect, the invention relates to a liquid composition comprising (A)
at least one fluorine-containing hydrocarbon containing 1 to 2 carbon atoms, and a
lubricant (B) at least one ester lubricant selected from the group consisting of (i) an
lS ester of a polyhydroxy compound and a monocarboxylic acylating agent selected from
the group consisting of branched monocarboxylic acylating agents having from about
4 to about 20 carbon atoms, straight chain monocarboxylic acylating agents having
from 8 to about 22 carbon atoms, and mixtures thereof, and (ii) an ester of
polyhydroxy compound and a combination of a dicarboxylic acylating agent and a
20 monocarboxylic acylating agent selected from the group consisting of branchedmonocarboxylic acylating agents having from about 4 to about 20 carbon atoms,
straight chain monocarboxylic acylating agents having from 8 to about 22 carbon
atoms, and mixtures thereof, and (C) at least one additive selected from the group
consisting of an alkyl phosphite, an alkyl phosphonic acid ester,a nitrogen-containing
25 heterocycle, and a mixture thereof.
Liquid compositions also are described wherein the fluorine-containing
hydrocarbons also contain other halogens such as chlorine. Methods of lubricating
refrigeration systems are also described. The liquid compositions are useful
particularly as refrigeration liquids in refrigerators and air-conditioners including
30 automotive, home, commercial and industrial air-conditioners.
~9'~7
Detailed DescAption of the Invention
Throughout this specification and claims, all parts and percentages are by
weight, temperatures are in degrees Celsius, and pressures are at or near atmospheric
pressure unless otherwise clearly indicated.
S As used in this specification and in the appended claims, the terms"hydrocarbyl" and "hydrocarbylene" denote a group having a carbon atom directly
attached to the polar group and having a hydrocarbon or predominantly h~drocarbon
character within the context of this invention. Such groups include the following:
(1) Hydrocarbon groups; that is, aliphatic, (e.g., alkyl or alkenyl), alicyclic
(e.g., cycloalkyl or cycloalkenyl), and the like, as well as cyclic groups wherein the
Ang is completed through another portion of the molecule (that is, any two indicated
substituents may together form an alicyclic group). Such groups are known to those
skilled in the art. Examples include methyl, ethyl, octyl, decyl, octadecyl,
cyclohexyl, etc.
(2) Substituted hydrocarbon groups; that is, groups containing
non hydrocarbon substituents which, in the context of this invention, do not alter the
predominantly hydrocarbon character of the group. Those skilled in the art will be
aware of suitable substituents. Examples include halo, hydroxy, alkoxy, etc.
(3) Hetero groups; that is, groups which, while predominantly hydrocarbon
in character within the context of this invention, contain atoms other than carbon in
a chain or ring otherwise composed of carbon atoms. Suitable hetero atoms will be
apparent to those skilled in the art and include, for example, nitrogen, oxygen and
sulfur.
In general, no more than about three substituents or hetero atoms, and
~5 preferably no more than one, will be present for each 10 carbon atoms in the
hydrocarbyl group.
Terms such as "alkyl", "alkylene", etc. have meanings analogous to the above
with respect to hydrocarbyl and hydrocarbylene.
~9~7
-7-
The term "hydrocarbon-based" also has the same mear~ing and can be used
interchangeably with the term hydrocarbyl when referring to molecular groups having
a carbon atom attached directly to the polar group.
The terrn "lower" as used herein in conjunction with terms such as
5 hydrocarbyl, hydrocarbylene, alkylene, alkyl, aL~cenyl, aLIcoxy, and the like, is
intended to describe such groups which contain a total of up to 7 carbon atoms, per
se, and includes methyl, ethyl, propyl, butyl, pentyl, hexyl, and heptyl groups.Viscosity, unless otherwise indicated, is kinematic viscosity and is measured
by ASTM D-2270.
For purpose of this invention, equivalent weight of polyol is determined by
dividing the formula weight of the polyol by the number of hydroxyl groups.
Equivalents of polyol is determined by dividing the amount of polyol by its equivalent
weight. For polycarboxylic acylating agents or anhydrides, the equivalent weight is
determined by dividing the formula weight of the acylating agent or anhydride by the
number of carboxylic groups which form esters. For example, an anhydride
contributes two carboxyl groups which can form ester. Therefore, the equivalent
weight of anhydride, such as succinic anhydride, would be the formula weight of the
anhydride divided by the number of carboxyl group. For succinic anhydride, the
number is two.
When a compolmd or component is indicated herein as being "soluble", the
compound or component is soluble in the liquid compositions of the invention
comprising the fluorine-containing hydrocarbon and the lubricant. For example, acompound or component is considcred "soluble" so long as it iS soluble ;n the liquid
compositions, even though it may be insoluble in the fluorine containing hydrocatbon
per se.
The term "consisting essentially of~' refers to compositions that include the
ingredients listed in the claim as well as other ingredients that do not materially affect
the basic and novel characteristics of the liquid compositions.
Generally the amount of fluorine-containing hydrocarbon is a major amount
for automotive and commercial and industrial refrigeration systems. Of course, lower
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-8-
arnounts, e.g. Iess ~han 50%, of the fluorine-containing hydrocarbon are useful, such
as in household refrigerators.
(A) Fluorine-Containing Hydrocarbon.
The liquid oompositions include at least one fluorine~ontaining hydrocarbon.
S That is, the fluorine-containing hydrocarbons contain at least one C-~I bond, as well
as C-F bonds. In addition to these two essential types of bonds, the hydrocarbon also
may contain other carbon-halogen bonds such as C-CI bonds. Because the liquid
compositions of the present invention are primarily intended for use as refrigerants,
the fluorine-containing hydrocarbon preferably contains one to three, or to two carbon
atoms, and more preferably two carbon atoms.
As noted above, the fluorine-containing hydrocarbons useful in the liquid
compositions of the present invention may contain other halogens such as chlorine.
However, in one preferred embodiment, the hydrocarbon contains only carbon,
hydrogen and fluorine. These compounds containing only carbon, hydrogen and
fluorine are referred to herein as fluorohydrocarbons or hydrofluorocarbons. Thehydrocarbons containing chlorine as well as fluorine and hydrogen are referred to as
chlorofluorohydrocarbons or hydrochlorofluorocarbons. The fluorine-containing
hydrocarbons useful in the composition of the present invention are to be
distinguished from the fully halogenated hydrocarbons which have been and are being
used as propellants, refrigerants and blowing agents such as CFC-ll, CFC-12 and
CFC-113 which have been described above.
Specific examples of the fluorine-containing hydrocarbons useful in the liquid
compositions of the present invention, and their reported ozone depletion potentials
are shown in the following Table I.
2 ~ 7
g
TABLE I
Compound
Designation Formula ODP*
HCFC-22 CHClF2 0.05
HCFC-123 CHCl2CF3 c 0.05
HCFC-141b CH3CCI2F < 0.05
~C-134a CH2FCF3 0
10 * Ozone depletion potential as reported in Process Engineering, pp. 33-34, July,
1988.
Examples of other fluorine-containing hydrocarbons which may be useful in
the liquid compositions of the present invention include trifluorornethane (HFC-23),
1,1,1-trifluoroethane (HFC-143a), 1,1-difluoroethane (HFC-152a),
2-chloro-1,1,1,2-tetrafluoroethane (HCFC-124), 1-chloro-1,1,2,2-tetrafluoroethane
(HCFC- 1 24a), 1 -chloro- 1,1 -difluoroethane (HCFC- 1 42b), and
1,1,2,2-tetrafluoroethane (HFC-134). Other refrigerants such as perfluoropropane(HFC-218), perfluorocyclopropane (HFC-216), perfluoropropylene oxide, 1,3-
20 perfluoro propylene oxide and pentafluorodimethyl ether may be used with the
lubricant. ln the refrigerant art, the fluorohydrocarbons are often identified merely
with the prefix "R" in place of the above letters. For example HFC-23 is R-23, and
HCFC-124 is R-124, etc.
In general, fluorine-containing hydrocarbons which are useful as refrigerants
25 are fluoromethanes and fluoroethanes boiling at a relatively low temperature at
atmospheric pressuM, e.g., below 30C. Mixtures of fluorine-containing
hydrocarbons may be used, and the amount of each fluorohydrocarbon in the mixture
may be varied as desired. Examples of fluorohydrocarbon mixtures useful as (A)
include: 142(b)/22; 134(a)/23; 22/124/152(a), etc. The useful fluorocarbon refriger-
30 ants serve to transfer heat in a refrigeration system by evaporating and absorbing heatat a low temperature and pressure, e.g., near ambient temperature and atmospheric
pressure, and by releasing heat on condensing at a higher temperature and pressure.
5 ~
-10-
The amount of fluoAne~ontaining hydrocarbon is the level typically used for
the refrigeration system. The liquid compositions of the present invention generally
contain from about 10%, or about 20% up to about 90%, or to about 85% of the
fluorine-containing hydrocarbon. In one embodiment, the fluorine-containing
hydrocarbon is present in an amount from about 45%, or about 50%, or about 55%
up to about 90%, or to about 80~o, or to about 75% by weight of the liquid
composition. More generally, the liquid compositions will comprise from about 50%
to about 99% by weight of the fluorine-containing hydrocarbon. In another embodi-
ment, the liquid compositions contain from about 70% to about 99% by weight of the
fluoAne-containing hydrocarbon. When the fluorine-containing hydrocarbon is usedat levels greater than 50/0 by weight of the lubAcant, then the liquid compositions are
generally suited for use as automotive and commercial and industrial refAgeration
systems.
In one embodiment, the fluorine-containing hydrocarbon is present in an
lS amount from about 10%, or about 25%, or about 30% up to about 55%, or to about
50%, or to about 45% by weight of the lubAcant. When the fluoAne-containing
hydrocarbon is present in an amount less than about 45 %, then the liquid
compositions ate generally suited for household refrigeration systems.
(B) Carboxylic Ester.
In addition to the fluorine-containing hydrocarbons descAbed above, the liquid
compositions also contain a lubAcant. The lubAcant contains at least one catboxylic
ester of a polycarboxylic acylating agent, preferably a dicarboxylic acylating agent
and a polyhydroxy compound, or a mixture of monocarboxylic and polycarboxylic
acylating agent, preferably dicarboxylic acylating agents and a polyhydroxy compound
containing at least two hydroxyl groups and characterized by the general formula
R[OC(O)RI]n (I)
wherein R is a hydrocarbyl group, each Rl is independently hydrogen, a straight
chain lower hydrocarbyl group, a branched chain hydrocatbyl group, or a straight
2~9 A~57
ehain hydrocarbyl group containing f~om about 8 to about 22 earbon atoms provided
that at least one Rl group is hydrogen, a lower straight ehain hydrocarbyl or a
branched ehain hydrocarbyl group, or a carboxylie aeid- or earboxylic
ester-eontaining hydroearbyl group, and n is at least 2.
S The carboxylic ester lubrieants utilized as eomponent (B) in the liquid
eompositions are reaction produets of one or more earboxylic acylating agents, e.g.
aeids or anhydrides (or the lower esters thereof sueh as methyl, ethyl, etc.), with
polyhydroxy compounds containing at least two hydroxyl groups. The polyhydroxy
eompounds may be represented by the general formu]a
~(OH)n (II)
wherein R is a hydrocarbyl group and n is at least 2. The hydrocarbyl group may
eontain from 4 to about 20 or more earbon atoms, and the hydrocarbyl group may
also eontain one or more nitrogen and/or oxygen atoms. The polyhydroxy
eompounds generally will eontain from about 2 to about 10 hydroxyl groups and more
preferably from about 3 to about 10 hydroxyl groups.
The polyhydroxy eompound may eontain one or more oxyalkylene groups,
and, thus, the polyhydroxy eompounds inelude compounds sueh as polyetherpolyols.The number of earbon atoms and number of hydroxyl groups eontained in the polyhy-
droxy eompound used to form the carboxylie esters may vary over a wide range, and
it is only necessary that the earboxylie ester produced with the polyhydroxy
eompounds be soluble in the liquid compositions .
The polyhydroxy compounds used in the preparation of the carboxylic esters
(I) also may eontain one or more nitrogen atoms. For example, the polyhydroxy
compound may be an alkanolamine eontaining from 3 to 6 hydroxyl groups. In one
preferred embodiment, the polyhydroxy eompound is an alkanolamine containing at
least two hydroxyl groups and more preferably at least three hydroxyl groups.
Specific examples of polyhydroxy compounds useful in the present invention
inelude ethylene glyeol, diethylene glyeol, triethylene glycol, propylene giycol,
~94~
-12-
dipropylene glycol, glycerol, neopentyl glycol, 1,2-, 1,3- and 1,4-butanediols,
pentaery~ritol, dipentaerythritol, tripentaerythritol, triglycerol, t~imethylolpropane,
di-trimethylolpropane, sorbitol, hexaglycerol, 2,2,4-trimethyl-1,3-pentanediol, etc.
Preferably, the mixtures of any of the above polyhydroxy compounds can be utilized.
S The carboxylic acylating agents utilized in the preparation of the carboxylic
esters useful in the liquid compositions may be characterized by the following
general formula
R'COOH (III)
wherein R' is (a) H, (b) a straight or branch chain lower hydrocarbyl group
(preferably about three to four carbon atoms), (c) a branched chain hydrocarbyl
group, or (d) a mixture of one or both of (b) and (c) with a straight chain hydrocarbyl
group containing from about 8 to about 22 carbon atoms or (e) a carboxylic acid- or
carboxylic acid ester-containing hydrocarbyl group. Stated otherwise, at least one R'
group in the ester product of Formula I must contain a lower straight chain
hydrocarbyl group or a branched chain hydrocarbyl group. The straight chain lower
hydrocarbyl group (R') contains from 1 to about 7 carbon atoms, and in a preferred
embodiment, contains from 1 to about 5 carbon atoms. The branch~d chain
hydrocarbyl group may contain any number of carbon atoms and will generally
contain from 4 to about 20 carbon atoms. In one preferred embodimcnt, the branched
chain hydrocarbon group contains from 5 to 20 carbon atoms and in a more prcferr~l
embodiment, contains from about 5 to about 14 carbon atoms. The higher molecularweight straight chain hydrocarbyl group containing from 8 to about 22 carbon atoms
will contain in some embodiments, from 8 to about 18 carbon atoms, and in more
preferred embodiments from 8 to about 14 carbon atoms.
2 ~ 7
-13-
In one embodiment, the branched chain hydrocarbyl groups are characteriz~d
by the structure
-C(R2)(R3~(R4
wherein R2, R3 and R4 are each independently alkyl groups, and at least one of the
alkyl groups contains two or more carbon atoms. Such branched chain alkyl groups,
when attached to a carboxyl group are referred to in the industry as neo groups and
the acids are referred to a neo acid. The neo acids are characterized as having alpha-
10 , alpha-, disubstituted hydrocarbyl groups. In one embodiment, R2 and R3 are methyl
groups and ~4 is an a~kyl group containing two or more carbon atoms.
Any of the above hydrocarbyl groups (R') may contain one or more carboxy
groups or carboxy ester groups such as -CooR5 wherein Rs is a lower alkyl,
hydroxyalkyl or a hydroxyalkyloxy group. Such substituted hydrocarbyl groups arepresent, for example, when the carboxylic acylating agent, R'COOH (III), is a
dicarboxylic acylating agent or a monoester of a dicarboxylic acylating agent.
Generally, however, the acid, R'COOH (III), is a monocarboxylic acid since
polycarboxylic acids tend to form polymeric products if the reaction conditions and
amounts of reactants are not carefully regulated. Mixtures of monocarboxylic acids
20 and minor amounts of dicarboxylic acids or anhydrides are useful in preparing the
esters (I).
Examples of carboxylic acylating agents containing a straight chain lower
hydrocarbyl group include formic acid, acetic acid, propionic acid, butyric acid,
valeric acid, hexanoic acid and heptanoic acid and anhydrides of any one thereof.
25 Examples of carboxylic acylating agents wherein the hydrocarbyl group is a branched
chain hydroc~rbyl group include isobutyric acid, 2-ethyl-n-butyric acid, 2-
methylbutyric acid, 2,2,4-trimethylpentanoic acid1 2-hexyldecanoic acid, isostearic
acid, 2-methylhexanoic acid, 3,5,5-trimethylhexanoic acid, 2-ethylhexanoic acid,isooctanoic acid, isononanoic acid, isoheptanoic acid, isodecanoic acid, neoheptanoic
30 acid, neodecanoic acid, and ISO Acids and NEO Acids available from Exxon
2 ~ 7
-14-
Chemical Company~ Houston, T~cas USA. ISO Acids are isomer mixtures of
branched 2cids and include commercial mi~tures such as ISO Heptanoic Acid, ISO
Octanoic Acid, and ISO Nonanoic Acid, as well as developmental products such as
ISO Decanoic Acids and ISO 810 Acid. Of the ISO Acids, ISO Octanoic acid and
5 ISO Nonanoic acid are preferred. Neo acids include commercially available mixtures
such as NEO Pentanoic Acid, NEO Heptanoic Acid, and NEO Decanoic Acid, as
well as developmental products such as ECR-909 (NEO C~) Acid, and ECR-903
(NEO C,2l4) Acid and commercial mixtures of branched chain carboxylic acids suchas the mixture identified as NEO 1214 acid from Exxon.
In a preferred embodiment, the ester is prepared from one of the polyhydroxy
compound described above and a monocarboxylic acylating agent having from about
4, or about 5, up to about 15, or to about 12, or to about 10 carbon atoms. The
monocarboxylic acylating agent may be linear or branched, preferably branched.
Particularly useful monocarboxylic acylating agents include branched monocarboxylic
15 acylating agents having 8 or 9 carbon atoms.
The third type of carboxylic acylating agent which can be utilized in the
preparation of the carboxylic esters are the acids containing a straight chain
hydrocarbyl group containing from 8 to about 22 carbon atoms. As noted previously,
these higher molecular weight straight chain acids can be utilized only in combination
20 with one of the other acids described above since the higher molecular weight straight
chain acids are not soluble in the fluorohydrocarbons. Examples of such higher
molecular weight straight chain acids include decanoic acid, dodecanoic acid, stearic
acid, lauric acid, behenic acid, etc.
In another embodiment, the carboxylic acylating agents utilized to prepare the
25 carboxylic esters may comprise a mixture of a major amount of monocarboxylic
acylating agents and a minor amount of dicarboxylic acylating agents. Examples of
useful dicarboxylic acylating agents include maleic acid or anhydride, succinic acid
or anhydride, adipic acid or anhydride, oxalic acid or anhydride, pimelic acid or
anhydride, glutaric acid or anhydride, suberic acid or anhydride, azelaic acid or
30 anhydride, sebacic acid or anhydride, etc. The presence of the dicarboxylic acylating
-lS- 2 ~ 5 ~
agents results in the formation of esters of higher viscosity. The complex esters are
formed by having a substantial portion of the dicarbo~ylic acylating agents react with
more than one polyol. The reaction is generally coupling of polyols through the
dicarboxylic acylating agent or anhydride. Examples of mi~tures of mono- and
5 dicarboxylic acylating agents include succinic anhydride and 3,5,5-trimethylhexanoic
acid; azelaic acid and 2,2,4-trimethylpentanoic acid; adipic acid and 3,5,5-
trimethylhexanoic acid; sebacic acid and isobutyric acid; adipic and a mixture of 50
parts 3,5,5-trimethylhexanoic acid and 50 parts neoheptanoic acid; and neoheptanoic
acid and a mixture of 50 parts adipic acid and 50 parts sebacic acid. The use of10 mixtures containing larger amounts of dicarboxylic acylating agents should be avoided
since the product ester will contain larger amounts of polymeric esters, and such
mixtures may be insoluble in the fluorohydrocarbons. An example of such a mixture
is 80 parts of neoheptanoic acid and 20 parts of succinic acid. Viscosity and average
molecular weight of the ester can be increased by increasing the amount of
15 dicarboxylic acid and decreasing the amount of monocarboxylic acylating agent.
The carboxylic esters of Formula I and the liquid compositions are prepared,
as mentioned above, by reacting at least one carboxylic acylating agent with at least
one polyhydroxy compound containing at least two hydroxyl groups. The formation
of esters by the interaction of carboxylic acylating agents and alcohols is acid20 catalyzed and is a reversible process which can be made to proceed ~o completion by
use of a large amount of alcohol or carboxylic acylating agent, or by removal of the
water as it is formed in the reaction. If the ester is formed by transesterification of
a lower molecular weight carboxylic ester, the reaction can be forced to completion
by removal of the low molecular weight alcohol formed as a result of a
25 transesterification reaction. The esterification reaction can be catalyzed by either
organic acids or inorganic acids. Examples of inorganic acids include sulfuric acids
and acidified clays. A variety of organic acids can be utilized including
paratoluenesulfonic acid and acidic resins, such as Amberlyst 15, etc. Organometallic
catalysts include, for example, tetraisopropoxy orthotitanate.
-1~ 2 ~ 7
The amounts of carboxylic acylating agents and polyhydroxy compounds
included in the reaction mi~ture may be varied depending on the results desired. If
it is desired to esterify all of ~e hydroxyl groups containing in the polyhydroxy
compounds, sufficient carboxylic acylating agent should be included in the mixture
to react vith all of the hydroxyl groups. When mixtures of the acylating agents are
reacted with a polyhydro~y compound in accordance with the present invention, the
carboxylic acylating agents can be reacted sequentially with the polyhydroxy
compounds or a mixture of carboxylic acylating agents can be prepared and the
mixture reacted with the polyhydroxy compounds. In one embodiment wherein
mixtures of acylating agents are utilized, the polyhydroxy compound is first reacted
with one carboxylic acylating agent, generally, the higher molecular weight branched
chain or straight chain carboxylic acylating agent followed by reaction with thestraight chain lower hydrocarbyl carboxylic acylating agent.
Throughout the specification and claims, it should be understood that the estersalso may be formed by reaction of the polyhydroxy compound with the anhydrides
of any of the above-described carboxylic acids. For example, esters are easily
prepared by reacting the polyhydroxy compounds either wi~h acetic acid or aceticanhydride.
In one embodiment, the esters are made by reacting a polyol with a mixture
of a dicarboxylic acylating agent and a monocarboxylic acylating agent. The amount
of dicarboxylic acylating agent and monocarboxylic acylating agent may be varied to
obtain a product for the desired result. In one embodiment, one equivalent of polyol
is reacted with from about 0.07, preferably from about 0.17 to about 0.33, prefeMbly
to about 0.23 moles of dicarboxylic acylating agent and from about 0.67, preferably
from about 0.77 to about 0.93, preferably to about 0.83 moles of monocarboxylic
acylating agent. Of course, more than one equivalent of acylating agent, and
particularly of monocarboxylic acid, may be used.
The formation of esters by the reaction of carboxylic acylating agents with the
polyhydroxy compounds described above can be effected by heating the acylating
agents, the polyhydroxy compounds, with or without a catalyst to an elevated
-17- 2 ~ 7
temperature while removing water, or low molecular weight alcohols or acids formed
in the reaction. GeneMlly, temperatures of from about 75C to about 2ûOC or
higher are sufficient for the reaction. The reaction is completed when water, or low
molecular weight alcohol or acid is no longer formed, and such completion is
indicated when water, or low molecular weight alcohols or acids can no longer beremoved by distillation.
In some instances, it is desired to prepare carboxylic esters wherein not all ofthe hydroxyl groups have been esterified. Such partial esters can be prepared by the
techniques described above and by utilizing amounts of the acid or acids which are
insufficient to esterify all of the hydroxyl groups.
The following examples illustrate the preparation of various carboxylic esters
(B) which are useful in the liquid compositions of the invention.
Example 1
A mixture of 92.1 parts (1 mole) of glycerol and 316.2 parts of acetic
lS anhydride is prepared and heated to reflux. The reaction is exothermic and continues
to reflux at 130C for about 4.5 hours. Thereafter the reaction mixture is maintained
at the reflux temperature by heating for an additional 6 hours. The reaction mixture
is stripped by heating while blowing with nitrogen, and filtered with a filter aid. The
filtrate is the desired ester.
Example 2
A mixture of 872 parts (6.05 moles) of 2-ethylhexanoic acid, 184 parts (2
moles) of glycerol and 20t) parts of toluene is prepared and blown wilh nitrogen while
heating the mixture to about 60C. Para-toluene sulfonic acid (S parts) is added to
the mixture which is then heated to the reflux temperaîure. A water/toluene
azeotrope distills at about 120C. A temperature of 125-130C is maintained for
about 8 hours followed by a temperature of 140C for 2 hours while removing water.
The residue is the desired ester.
Example 3
Into a reaction vessel there are charged 600 parts (2.5 moles) of triglycerol
and 1428 parts (14 moles) of acetic anhydride. The mixture is heated to reflux in a
2~9~7
-18-
nitrogen atmosphere and maintained at the reflux temperature (125-130C) for about
9.5 hours. The reaction mixture is nitrogen stripped at 150C and 15 mm.Hg. The
residue is filtered through a filter aid, and the filtrate is the desired ester. Example 4
A reaction vessel is charged with 23 parts (0.05 mole) of hexaglycerol and
43.3 parts (0.425 mole) of acetic anhydride. The mixture is heated to the refluxtemperature (about 139C) and maintained at this temperature for a total of about 8
hours. The reaction mixture is stripped with nitrogen and then vacuum stripped to
150C at 15 mm.Hg. The residue is filtered through a filter aid, and the filtrate is
the desired ester.
Example 5
A mixture of 364 parts (2 moles) of sorbitol, and 340 parts (2 moles) of a
commercial C8,0 straight chain methyl ester (Procter & Gamble), is prepared and
heated to 180C. The mixture is a two-phase system. Para-toluene sulfonic acid (1
part) is added, and the mixture is heated to 150C whereupon the reaction commences
and water and methanol evolve. When the solution becomes homogeneous, 250 parts
(2.5 moles) of acetic anhydride are added with stirring. The reaction mixture then
is stripped at 150C and filtered. The filtrate is the desired ester of sorbitol.
Example 6
A mixture of 536 parts (4 moles) of trimethylolpropane and 680 parts (4
moles) of a commercial C8,0 straight chain methyl ester is prepared, and 5 parts of
tletraisopropoxy orthotitanate are added. The mixture is heated to 200C with
nitrogen blowing. Methanol is distilled from the reaction mixture. When the
distillation of methanol is completed by nitrogen blowing, the reaction temperature
is lowered to 150C, and 408 parts (4 moles) of acetic anhydride are added in a slow
stream. A water azeotrope begins to evolve when 50 parts of toluene are added.
When about 75 parts of a water/acetic acid mixture has been collected, the distillation
ceases. Acetic acid (50 parts) is added and additional water/acetic acid mixture is
collected. The acetic acid addition is repeated with heating until no water can be
removed by distillation. The residue is filtered and the filtrate is the desired ester.
2~9~a7
-lg-
Exarnple 7
A mixture of 402 parts (3 moles) of trimethylolpropane, 660 parts (3 moles)
of a commercial straight chain methyl ester comprising a mixture of about 75% Cl2
methyl ester and about 25% Cl4 methyl ester, (CE1270 from Procter & Gamble), and5 tetraisopropoxy orthotitanate is prepared and heated to 200C with rnild ni~rogen
blowing. The reaction is allowed to proceed overnight at this temperature, and in 16
hours, 110 parts of methanol is collected. The reaction mixture is cooled to 150C,
and 100 parts of acetic acid and 50 parts of toluene are added followed by the
addition of an additional 260 parts of acetic acid. The mixture is heated at about
150C for several hours yielding the desired ester.
Example 8
A mixture of 408 parts (3 moles) of pentaerythritol and 660 parts (3 moles)
of the CE1270 methyl ester used in Example 7 is prepared with 5 parts of tetraiso-
propyl orthotitanate, and the mixture is heated to 220C under a nitrogen purge. No
reaction occurs. The mixture then is cooled to 130C, and 250 parts of acetic acid
are added. A small amount of para-toluenesulfonic acid is added and the mixture is
stirred at about 200C for 2 days, and 60 parts of methanol are removed. At thistime, 450 parts of acetic anhydride are added and the mixture is stirred at 150C until
the acetic acidlwater azeotrope no longer evolves. The residue is filtered through a0 filter aid, and the filtrate is the desired ester of pentaerythritol.
Example 9
A mixture of 850 parts (6.25 moles) of pentaerythritol, 3250 parts (25 moles)
of neoheptanoic acid, and 10 parts of tetraisopropoxy orthotitanate is prepared and
heated to 170C. Water is evolved and removed by distillation. When the evolution
25 of water ceases, 50 parts of acidified clay are added and some additional water is
evolved. A total of about 250 parts of water is removed during the reaction. Thereaction mixture is cooled to room temperature and 310 parts of acetic anhydride are
added to esterify the remaining hydroxyl groups. The desired ester is obtained.
~9~7
-20-
Exarnple 10
A mixture of 544 parts (4 moles) of pentaerythritol, 820 parts (4 moles) of
Neo 1214 acid, a commercial acid mi~ture available from Exxon, 408 parts (4 moles)
of acetic anhydride and 50 parts of Amberlyst 15 is prepared and heated to about120C whereupon water and acetic acid begin to distill. After about 150 parts ofwater/acetic acid are collected, the reaction temperature increases to about 200C.
The mixture is maintained at this temperature of several days and stripped. Acetic
anhydride is added to esterify any remaining hydroxyl groups. The product is filtered
and the filtrate is the desired ester.
Example 11
A mixture of 1088 parts (8 moles) of pentaerythritol, 1360 parts (8 moles) of
a commercial methyl ester of an acid mixture comprising about 55% of C8, 40% of
C10 and 4% of C6 acids (nCE810 Methyl Ester", Procter & Gamble), 816 parts of
acetic anhydride and 10 parts of paratoluene sulfonic acid is prepared and heated to
lS reflux. About S00 parts of a volatile material are removed. A water azeotrope
mixture then distills resulting in the removal of about 90 parts of water. Acetic
anhydride (700 parts) is added and the mixture is stirred as a water/acetic acidmixture is removed. The reaction is continued until no more water is evolved andno free hydroxyl groups remain (by IR). The reaction product is stripped and
filtered.
Example 12
A mixture of 508 parts (2 moles) of dipentaerythritol, 812 parts (8 moles) of
acetic anhydride, 10 parts of acidified clay as catalyst and 100 parts of xylene is
prepared and heated to 100C. This temperature is maintained until the solid
dipentaerythritol is dissolved. A water/acetic acid azeotrope is collected, and when
the rate of evolution diminishes, the reaction mixture is blown with nitrogen. About
100-200 parts of acetic acid are added and the reaction is continued as additional
water/acetic acid/xylene azeotrope is collected. When an infrared analysis of the
reaction mixture indicates a minimum of free hydroxyl groups, the reaction mixture
is stripped and filtered. The filtrate is the desired product which solidifies.
-21- 2~9~7
E~ample 13
A n~ixture of 320 parts (1.26 moles) of dipentaerythritol, 975 parts (1.25
moles) of neoheptanoic acid and 25 parts of Amberlyst 15 catalyst is prepared and
heated to 130C. At this temperature water evolution is slow, but when the
Stemperature is raised to 150C, about 65% of the theory water is collected. The last
amounts of water are removed by heating to 200C. The product is a dark viscous
liquid.
Example 14
A mixture of 372 parts (1 mole) of tripentaerythritol, 910 parts (7 moles) of
10neoheptanoic acid and 30 parts of Amberlyst 15 catalyst is prepared and heated to
110C as water is removed. The mixture is heated for a total of 48 hours, and
unreacted acid is removed by stripping the mixture. The residue is the desired ester.
Example 15
A mixture of 1032 parts (6 moles) of neodecanoic acid, 450 parts (3 moles)
15of triethylene glycol and 60 parts of Amberlyst 15 is prepared and heated to 130C.
A water azeotrope is evolved and collected. The residue is the desired product.
Example 16
A mixture of 1032 parts (6 moles) of neodecanoic acid and 318 parts (3 moles)
of diethylene glycol is prepared and heated to 130C in the presence of 20 parts of
20Amberlyst 15. After heating for 24 hours and removing about 90 parts of water, 20
parts of Amberlyst 15 are added and the reaction is conducted for another 24 hours.
The reaction is stopped when the theory amount of water is obtained, and the residue
is the desired ester~
Example 17
25A reaction vessel is charged with 2010 parts (15 moles) of trimethylolpropane,6534 parts (45 moles~ of 2,2,4-trimethylpentanoic acid (available commercially from
Exxon Corporation under the trade name ISO Octanoic acid), and 8 parts of
methanesulfonic acid~ The mixture is heated to 150C and water is removed~ The
temperature is increased to 200C and the temperature is maintained for eight hours~
30After water evolution, the reaction mixture is vacuum stripped to 200C and 20 mm
2~4~57
-22-
Hg. The residue is filter~d and the filtrate is the desired product. The product has
a neutralization acid number of 0.06 and a kinematic viscosity of 32 cSt at 40C.
Example 18
A reacdon vessel is charged with 2814 parts (21 moles) of trimethylolpropane,
6854 parts (67 moles) of isopentanoic acid (available commercially from Union
Carbide), which is a mixture of 66% by weight valeric acid and 34% by weight 2-
methylbutyric acid), 5 parts methanesulfonic acid, 50 parts of an aromatic solvent.
The reaction mixture is heated to 145C over three hours. The reaction mixture is
heated to 165C over three hours. The temperature of the mixture is maintained for
13 hours. A total of 1100 milliters of water is collected. The reaction mixture is
vacuum stripped to 180-200C and 10-15 mm Hg. The residue is filtered and the
filtrate is the desired product. The product has a 0.009 acid number, and a kinematic
viscosity of 10.2 cSt at 40C and 2.65 cSt at 100C.
Example 19
A reaction vessel is charged with 2345 parts (17.5 moles) of
trimethylolpropane7 and 8295 parts (52.5 moles) of 3,5,5 trimethylhexanoic acid (
available commercially from Exxon Corporation under the trade name ISO Nonanoic
acid). The mixture is heated to 150C and the temperature is maintained for 12
hours. The reaction mixture is then heated to 200C and the temperature is
maintained for 38 hours. The reaction is then heated to 220C and the temperature
is maintained for 14 hours. The reaction mixture is vacuum stripped to 200C and10-15 mm Hg. Alumina (275 parts) is added to the residue and the residue is
filtered. The filtrate is the desired product. The product has a zero acid number, and
a kinematic viscosity of 52.8 cSt at 40C and 7.1 cSt at 100C.
Example 20
A mixture of 200 parts (2 moles) of succinic anhydride and 62 parts (1 mole)
of ethylene glycol is heated to 120C, and the mixture becomes a liquid. Five parts
of acidic clay are added as catalyst, and an exotherm to about 180C occurs.
Isooctanol (260 parts, 2 moles) is added, and the reaction mixture is maintained at
130C as water is removed. When the reaction mixture becomes cloudy, a small
2~8~7
-23-
amount of propanol is added and the rnixture is stirred at 100C overnight. The
reaction mixture then is filtered to remove traces of oligomers, and the filtrate is the
desired ester.
Example 21
S A mixture of 200 parts (2 moles) of succinic anhydride, 62 parts (1 mole) of
ethylene glycol and 1 part of paratoluene sulfonic acid is prepared and heated to
80-90C. At this temperature, the reaction begins and an exotherm to 140C results.
The mixture is stirred at 130-140C for 15 minutes after 160 parts (2 moles) of
2,2,4-trimethylpentanol are added. Water evolves quiclcly, and when all of the water
is removed, the residue is recovered as the desired product.
Example 22
A mixture of 294 parts (3 moles) of maleic anhydride and 91 parts (1.5 moles)
of ethylene glycol is prepared and heated at about 180C whereupon a strong
exotherm occurs and the temperature of the mixture is raised to about 120C. When
the temperature of the mixture cools to about 100C, 222 parts (3 moles) of n-butyl
alcohol and 10 parts of Amberlyst 15 are added. Water begins to evolve and is
collected. The reaction mixture is maintained at 120C until 50 parts of water is
collected. The residue is filtered, and the filtrate is the desired product.
Example 23
A mixture of 1072 parts (8 moles) of trimethylolpropane, 2080 parts (16
moles) of neoheptanoic acid and 50 parts of Amberlyst 15 is prepared and heated to
about 130C. A watertacid azeotrope evolves and is removed. When about 250 of
the azeotrope has been removed, 584 parts (4 moles) of adipic acid are added and the
reaction continues to produce an additional 450 parts of distillate. At this time, 65
parts of trimethylolpropane are added to the mixture and additional water is removed.
The residue is filtered and the filtrate is the desired ester.
Example 25
Esters are prepared by reacting mixtures of isononanoic acid (1) and adipic
acid (2) with trimethylolpropane (3), in the presence of a tetraisopropoxy orthotitanate
catalyst. The reactants are charged to a flask and heated until reaction ceases, as
2~9~8~7
-24-
indicated by termination of water coll~ction in a distillation trap, at which pc,int the
reaction mixture has reached a'oout 220C. A vacuum is applied to remove volatile
components, and tne flask contents are cooled and filtered to produce the liquid ester
product.
Properties of the products are as follows:
Moles Catalyst, Viscosity, cSt Molecular
Product (1! (2) ~ ~rams 40C 100C Wei~ht
A 44 2 16 13 76.6 9.1 611
B 40 4 16 12 116 12.3 694
C 16 2 6.7 S 141 13.9 723
As can be seen, increasing the fraction of dicarboxylic acid results in a higherviscosity, higher average molecular weight (as measured by vapor phase osmometry)
ester material.
Example 26
The procedure of Example 25 is used to prepare esters from isononanoic acid
(1), adipic acid (2) and neopentylglycol (3), giving the following product properties:
Moles Catalyst, Viscosity, cSt Molecular
Product Ll~ ~ ~ ~m~ 4QC lOQC Wei~ht
A 2 1 2 2 80 10.5 588
B 10.7 6.7 12 5 106 13.2 665
C 8.3 8.3 12.5 8 220 22.1 758
Example 27
The procedure of Example 25 is used to prepare esters from isononanoic
acid (1), isooctanoic acid (2), isobutyric acid (3), adipic acid (4) and pentaerythritol
(5), giving the following product properties:
2~948~
-25-
Moles Catalyst
Pr~duct Ll~ ~ ~ (4) ~ ~Lms
A 7 7 7 1.5 6 5
B 7.2 7.2 6 1.8 6 5
s
Product Viscosity, cSt Molecular
40C 100C Wei~ht
A 149.5 14.0 733
B 194 16.9 802
Example 28
The procedure of Example 25 is used to prepare the ester in Table 3.
TABLE 3
Moles
Adipic iso Nonanoic
~m~ç ~~ Acid Acid (2)
Comparative
Examp]e 1 0 3
28A 1 0.1 2.8
28B 1 0.125 2.75
28C 1 0.25 2.45
28D I 0.30 2.4
28E 1 0.35 2.3
2~9~8~7
-26-
Viscosity
~40C ~100C
Example 52.25 7.25
28A 69.4 8.65
28B 76.6 9.14
28C 119 12.3
28D 140 14
28E 185 16.8
(1) TMP - TAmethylolpropane
(2) Available from Exxon Chemical Company
As can be seen from Table 3, as the level of dicarboxylic acid is increased,
the viscosity of the ester increases.
The carboxylic ester lubAcants preferably contain branched alkyl groups and
generally are free of acetylenic and aromatic unsaturation. Some ester which contain
15 such unsaturation may be insoluble in the fluorine-containing hydrocarbons. In one
embodiment, the soluble ester lubricants of this invention also are preferably free of
olefinic unsaturation except that some olefinic unsaturation may be present so long
as the lubAcant is soluble.
The carboxylic ~sters are soluble in the fluorine-containing hydrocarbons and,
20 in particular, in the fluorohydrocarbons such as 1,1,1,2-tetrafluoroethane. The
carboxylic esters are soluble over a wide temperature range and, in particular, at low
temperatures. The solubility of the lubricants in fluorohydrocarbons such as
1,1,1 ,2-tetrafluoroethane at low temperatures is determined in the following rranner.
The lubricant (0.5 gram) is placed in a thick-walled glass vessel equipped with a
25 removable pressure gauge. The tetrafluoroethane (4.5 grams) is condensed into the
cooled (-40C) glass vessel, and the contents are warmed to the desired temperature
and mixed to determine if the lubricant is soluble in the tetrafluoroethane, If soluble,
the temperature of the mixture is reduced until a separation and/or precipitate is
observed. The results of this solubility test conducted with several examples of the
30 carboxylic ester lubAcants are summarized in the following Table II.
2~9~8~7
-27-
TABLE II
Liquid ContainingSolubility
Product of Example C (~t.!
6 ~5
-50
11 ~0
12 -50
13 -15
-30
16 10
17 -29
19 -40
-25
22 -10
25(A) -35
25(B) -30
25(C) -30
In one embodiment, the liquid compositions comprise a major amount of a
fluorine-containing hydrocarbon and a minor amount of at least one soluble organic
lubricant comprising at least one carboxylic ester. By "major amount" is meant an
amount greater than 50% by weight such as 50.5 %,70%,99%, etc. The term "minor
amount" includes amounts less than 50% by weight such as 1%, 5%, 20%, 30% and
up to 49.9%. In one embodiment, the liquid compositions will comprise from about70% to about 99% of the fluorine-containing hydrocarbon and from about 1 to about
30% by weight of the lubricant. In other embodiment, the liquid compositions maycontain from about 5% to about 20% by weight of the lubricant.
The liquid compositions may additionally contain (C) at least one additive
selected from the group consisting of an alkyl phosphite, an alkyl phosphonic acid
ester, a nitrogen-containing heterocycle, and a mixture thereof. The phosphite and/or
the alkyl phosphonic acid ester are present in an amount sufficient to provide antiwear
2~9~857
-28-
and/or extreme pressure properties to the lubricant and liquid composition. The
phosphite and/or the alkyl phosphonic acid ester are present in an amount to provide
0.0~1%, or to 0.015 %, or about 0.025%, to about 1%, or to ahout 0.5 %, or to about
0.2% by weight phosphorus to the lubricant. The nitrogen~ontaining heterocycle is
present in an amount from about 0.001%, or about 0.02%, or about 0.03% up to
about 5%, or to about 2%, or to about 1%, or to about 0.5% by weight of the
lubricant.
The phosphite and/or the alkyl phosphonic acid ester provide beneficial
antiwear and extreme pressure properties to the liquid compositions. The phosphite
may be a dialkyl or trialkyl phosphite, preferably a dialkyl phosphite. The alkyl
phosphonic acid ester may be an alkyl phosphonic acid diester, preferably a
dialkylester. The alkyl groups of the phosphite and the phosphonic acid ester
independently contain from 1, or about 3 to about 20, or to about 18, or to about 8
carbon atoms. In one embodiment, the phosphite and the phosphonic acid ester have
alkyl groups independently containing from about 3 to about 6, or to about 5 carbon
atoms. A number of dialkyl phosphites are commercially available, such as lower
dialkyl phosphites, which are preferred. Lower dialkyl phosphites include dimethyl,
diethyl, dipropyl, dibutyl, dipentyl and dihexyl phosphites. Phosphites and their
preparation are known and many phosphites are available commercially. Also mixedalkyl phosphites, made from a mixture of alcohols, are useful in the present inven-
tion. Examples of mixtures of alcohols include ethyl and butyl alcohol; propyl and
pentyl alcohol; and methyl and pentyl alcohol. A particularly useful phosphite is
dibutyl phosphite.
Alkyl phosphonic acid esters are prepared by means known to those in the art.
For example, alkyl phosphonic acid esters may be prepared by reacting an alkyl
halide with a trialkyl phosphite. Examples of alkyl phosphonic acid esters include
diethyl, butylphosphonate; dibutyl,butylphosphonate; 2-ethylhexyl,2-
ethylhexylphosphonate, etc.
The lubricant may additionally contain a nitrogen-containing heterocycle, such
as dimercaptothiadiazoles, triazoles, amino-mercaptothiadiazoles, imidazoles,
2 ~ 7
-29-
thiazoles, tetrawles, hydroxyquinolines, oxazolines, imidazolines, ~iophenes,
indoles, indazoles, quinolines, benzoxazines, dithiols, oxazoles, oxatriazoles,
pyridines, pipe~azines, triazines, and derivatives of any one or more thereof. In one
embodiment, the nitrogen containing heterocycle is a ~riazole or derivative thereof,
a thiawle or derivative thereof, a mercaptothiazole or derivative thereof and a
thiadiazole or derivative thereof, preferably a triazole or derivative thereof. These
additives provide metal deactivating, metal passivating and corrosion controlling
character to the liquid compositions. Examples of useful met~l deactivators include
dimercaptothiadiazoles and derivatives thereof, substituted and unsubstituted triazoles
(e.g., benzotriazole, tolyltriazole, octylbenzotriazole, and the like),
mercaptobenwthiawles, etc. Examples of these compounds are benwtriazole, alkyl-
substituted benzotriazole (e.g., tolyltriazole, ethylbenzotriazole, hexylbenzotriazole,
octylbenzotriazole, etc.), aryl-substituted benzotriazole (e.g., phenol benzotriazoles,
etc.), and alkylaryl- or arylalkyl-substituted benzotriazole and substituted
benzotriazoles where the substituent may be hydroxy, alkoxy, halo (especially
chloro), nitro, carboxy and carboxyalkoxy. Preferably, the triazole is a benzotriazole
or an alkylbenzotriazole in which the alkyl group contains 1 to about 20 carbon
atoms, preferably 1 to about 8 carbon atoms.
The nitrogen containing heterocycle (C) may also be the reaction product of
at least one of the above triazoles, at least one amine and an aldehyde or aldehyde
precursor. The triazole is preferably a benzotriazole. The amine can be one or more
mono- or polyamines. These monoamines and polyamines can be primary amines,
secondary amines or tertiary amines. E.xamples of polyamines include
polyalkylenepolyamines, and heterocyclic polyamines. The polyalkyleneamines
include polyethylenepolyamines, such as diethylenetriamine, triethylenetrimine,
tetraethylenepentaamine, etc.
The aldehyde is typically a hydrocarbon-based aldehyde, preferably a lower
aliphatic aldehyde. Suitable aldehydes include formaldehyde, benzaldehyde, acetalde-
hyde, the butyraldehydes, hydroxybutyraldehydes and heptanals, as well as aldehyde
precursors which react as aldehydes under the conditions of the reaction such as
2~94~57
-30-
paraformaldehyde, paraldehyde, formalin and methanal. Formaldehyde and its
precursors ~eOg., paraformaldehyde, trioxane) are preferred. Mi~tures of aldehydes
may be used.
An example of a useful triazole derivative is Reomet~ 39. This material is a
5~iazole derivative available commercially from Ciba-Geigy Corporation.
The liquid compositions are characterized as having improved thermal and
chemical stability over a wide temperature range. The liquid compositions have
improved antiwear and corrosion stability properties. The liquid compositions have
beneficial viscosity properties. Preferably the liquid compositions have a viscosity
10of 5-400 centistokes (cSt) measured at 40C.
Liquid compositions containing carboxylic esters derived from neo polyols
such as neopentylglycol, trimethylolpropane and pentaerythritol, have beneficialthermal and hydrolytic stability. Liquid compositions containing carboxylic esters
derived from branched acids, such as iso or neo acids, preferably neo acids, have
15improved thermal and hydrolytic stability. In one embodiment, the carboxylic esters
are derived from the above polyols, a polycarboxylic acid and an iso or neo acid.
The liquid composition may contain one carboxylic ester reaction product or in
another embodiment, the liquid compositions may contain a blend of two or more
carboxylic ester reaction products. A liquid composition of a desired viscosity may
20be prepared by blending a higher viscosity carboxylic ester with a lower viscosity
carboxylic ester. Other additives, if soluble in the liquid, known to be useful for
improving the properties of halogen-containing hydrocarbon refrigerants can be
included in the liquid compositions to improve the characteristics of the liquid as a
refrigerant. However, hydrocarbon oils such as mineral oil generally are not included
25in and are most often excluded from the liquid compositions of the invention,
particularly when the fluorine-containing hydrocarbon contains no other halogens.
Hydrocarbon lubricants, however, may be present if the liquid compositions are used
to retrofit a compressor system which had previously used a hydrocarbon lubrican~.
Other additives may be included in the liquid compositions of the present
30invention to enhance the performance of the liquids include extreme-pressure and
~0~48~7
-31-
anti-wear agents, oa~idation and thermal-stability improvers, corrosion-inhibitors,
viscosity-index improvers, pour point andtor floc point depressants, detergents,dispersants, anti-foamin~ agents, viscosity adjusters, metal deactivators, etc. As
noted above, these supplementary additives must be soluble in the liquid compositions
5 of the invention. Included among the materials which may be used as
extreme-pressure and antiwear agen~s arephosphates, phosphateesters, thiophosphates
such as zinc diorganodithiophosphates, chlorinated waxes, sulfurized fats and olçfins,
organic lead compounds, fatty acids, molybdenum complexes, borates,
halogen-substituted phosphorous compounds, sulfurized Diels Alder adducts, organic
10 sulfides, metal salts of organic acids, etc. Sterically hindered phenols, aromatic
amines, dithiophosphates, sulfides and metal salts of dithioacids are useful examples
of oxidation and thermal stability improvers. Compolmds useful as
corrosion-inhibitors include organic acids, organic amines, organic phosphates,
organic alcohols, metal sulfonates, etc. VI improvers include polyolefins such as
15 polyester, polybutene, polymethacrylate, polyalkyl styrenes, etc. Pour point and floc
point depressants include polymethacrylates, ethylene- vinyl acetate copolymers,succinamic acid-olefin copolymers, ethylene-alpha olefin copolymers, etc. Detergents
include sulfonates, long-chain alkyl-substituted aromatic sulfonic acids, phenylates,
metal salts of alkyl phenols, alkyl phenol-aldehyde condensation products, metal salts
20 of substituted salicylates, etc. Silicone polymers are a well known type of anti-foam
agent. Viscosity adjusters are exemplified by polyisobutylene, polymethacrylates,
polyalkyl styrenes, naphthenic oils, alkyl benzene oils, polyesters, polyvinyl chloride,
polyphosphates, etc.
The following examples (TABI,E 1) relatc to formulations which are uscful
25 as organic lubricant (B) in the present invention.
2~9~7
X ~ o o o o
o
o
o o
x
o
o o ~,
oo
O O,~
X
E3 ~ E
~ ~
,_ o ~ 'C
~ ,~
o m
l,7 0
2~48~7
-33-
The liquid compositions of the present invention are particularly useful as
refrigerants in various refrigeration sys~ems which are compression-type systems such
as refrigerators7 freezers, and air-conditioners including automotive, home and
industrial air~onditioners. The following examples are illustrative of the liquid
S compositions of the present invention.
Parts ~y Wt.
Example A
1,1,1,2-tetrafluoroethane (HFC-134a) 90
Lubricant of Example 17 10
DBPH 0.625
Benzotriazole 0.02
Example B
1,1,1 ,2-tetrafluoroethane 85
Lubricant of Example 19 15
DBBP 0.2
~xample C
HFC-134a 55
Lubricant of Example 6 45
Dibutyl phosphite 0.05
benzotriazole 0.01
Example D
HFC-134a 60
Product of Example 18 40
tolyltriazole 0.025
~ame~e
HFC-134a 85
Product of Example 19 15
Reomet0 39 0.02
2~9~8~7
-34-
Table 2 contains further examples of the liquid compositions of the present
invention.
Table 2
F E H
HFC-134a 80 85 55 90 45
Lubricant of
Example:
V 15 10
VII 45 55
While the invention has been explained in relation to its preferred
embodiments, it is to be understood that various modifications thereof will become
apparent to those skilled in the art upon reading the specification. Therefore, it is to
15 be understood that the invention disclosed herein is intended to cover such
modifications as fall within the scope of the appended claims.
_35- 2~9~7
245~03
Example References
Example Source
1-16 245~02
17 1069N-133
18 928N-3
19 1066n-59
20-28 245~02
