Note: Descriptions are shown in the official language in which they were submitted.
1310832
ElACE~GROl~ND O~ T~3E INVE~ITION
1. Field_o~ th _I vention
This invention relates generally to novel fuel
compositions for spark ignition internal combustion
engines. ~ore particularly, it relates to a novel
additive combination for "nonleadedn gasoline
composition 5 .
2. Descriptlon of the Prior Art
The incorpocation o e vacious organo-metallic
compounds as antiknock agents in fuels for high
compression, spark ignited, intecnal combustion
enyines has been practiced for some time. The most
common organo-metallic compound used foc this purpose
is tetraethyl lead ~"TEL"). Generally these
organo-metallic compounds have secved well as
antiknock ~gents. ~owever, certain environmental
hazards are now assoc1ated with the alkyl lead
components of these compound~. This circumstance haS
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precipitated a series of Environmental Protection
Agency ( ~EPA" ) mandates almed at completely phasing
out leaded gasolines.
Many alternatives to these organo-metallic
S compound~ also have been proposed and/or used. For
example organomanganese compounds such as cyclomatic
m a n g a n e s e t r i c a r b o n y l s, p a r t i c u l a r l y
methylcyclopentadienyl manganese tricarbonyl ~nMMT"),
were once accepted alternatives to TEL. However,
these compounds produced another set of environ~ental
problems. Their use tends to steadily increase the
amount of unoxidized and/or partially oxidi~ed
hydrocarbons emitted from engines commonly reeerred to
as "engine out hydrocarbons" ~EOHC). Fuels containing
such organomanganese compounds gradually cause the
emission of substantially higher le;vels of
hydrocarbon~ than are permitted under law.
Aggravating the alr pollution problem, such
organomanganese compounds, particularly MMT, when used
at concentrations greater than about 1/16 per gram
manganese per gallon, are believed to be responsible
for catalytic converter plug~ing. Accordingly, under
Federal Law the use of MMT is currently banned in all
unleaded gasolines.
It is well known in the art that many lower
molecular weight aliphatic alcohols possess antiknock
- properties. They have been used as motor fuels in
their own right and they have also been used as
antiknock additives in both leaded and nonleaded
gasoI lnes .
F~s might be expected, many attempts have been made
to combine tetraethyl lead, cyclomatic n~anganese
tr icarbonyls, and/or lower al iphatif alcohols with
petroleum hydrocatbon products boiling within the
gasoline range. Some combinations are the result of
chemical compounding, while others represent
noncompounded physical blends in various combinations.
Certain combinations of the~e ingredients have been
blended wlth or without the use of stabilizers. U.S.
1310~2
Patent 3,030,195 (the "1~5 patent") well summari~es
the results of prior art efforts to physicslly blend
TEL, MMT and certain lower aliphatic alcohol antiknock
agent6 in gasoline wlthout the aid of stabilizing
agent3. For example~ the 195 patent points out that
when lower aliphatic alcoho]s and TEL type compounds
are present together in petroleum hydrocarbon
gasolines, the antiknock effect achieved by the
~ combination is substantially lower than would be
,~ 10 expected in view of their known individual antiknock
efficacies. This phenomena is commonly referred to as
negative lead susceptibilitiesn. The 195 patent
teaches that a positive synergism in the antiknock
properties of leaded gasoline/alcohol fuel
compositions can be obtained by adding a cyclomatic
manganese tricarbonyl such as MMT to leaded gasoline
compositions. However, at this time the.technlcal
advantages produced by such fuel compositions are
belng effectively negated by the phase out oE lead
~ontaining antlknock addltives.
Other investigations aimed at describing the
physical properties of leaded gasoline/alcohol blends
have shown that n-propanol and i-butanol give smaller
octane increases than methanol or ethanol in leaded
gasolines/alaohol blends. The antiknock qualitie~ o~
nonleaded gasoline/alcohol blends have also been
investlgated. The3e investigations also indicate that
alcohols in general are considerably more effectlve
octane improvers in blends utilizing low octane
ga~oline components a~ compared to high octane
gasolines. See, for example, Cox, Frank W., PIIYSICAL
PROPERTIES OF GASOLINF/ALCOHOL BLENDS, Bartlesville
Energy Technology Center, Bartlesvillet Oklahoma
(1979).
- 35 It is also wel'l known that lower molec~llar weight
aliphatic alcohols and gasoline when blended together
~` form nonideal mixtures with respect to octane
numbers. This nonideal behavior results in an
;, additional benefit in that the actual increase in
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octane value of a gasoline~alcohol mixture is greater
than that expected from the amount of alcohol added
and the octane value of the gasoline taken
separately. Consequently, those skilled in this art
5 generally use the octane value, known as "blending
octane value" or the average of resear~h and motor
octane (R ~ M)/2, to estimate the effect of alcohol on
the ga~oline base. For example, depending upon the
octane values of the base gasollne, methanol/ga301ine
, 10 blends have been reported to be 2 to 3 Motor Octane
Number and as high~ as 16 Re3earch Octane Number above
the reported values for the base gasoline. In any
event, ~uch finished methanol/gasoline fuels normally
are 1.5 to 3 octane points ~R + M)/2 higher than the
base fuel it3elf. 5ee for example, Eccleston~ B.H.
a nd Cox, F.W., PIIYSIC~L PROPE:RTIES OF
: GASOLINF/METilANOL MIXTURES, ~artlesvilie Energy
Research Center, Bartle~ville~ Oklahoma (1977).
Notwith~tanding the~e antiknock benefits, methanol
by itself i9 not widely used as a gasoline additive
due to the number of serious technical and legal
prohlems assoclated with its use. In the technical
realm, tha presence of even small amounts of water can
cause serious operational problems. Methanol when
used by itself (and to a lesser extent ethanol) tends
to phase-separate from gasoline in the presence of
water and~or when exposed to cold weather conditions.
This tendency to pha~e-separate has been a major
obstacle to the use of such alcohols as octane
enhancers and gasoline extenders. Further, methanol,
particularly when it has phase-separated from
- gasoline, is known to have harmful corrosive
tendencies to certain fuel delivery and engine
components.
For these and other reasons, Section 211~f)~a) of
the Clean Air ~ct, as amanded (42 USC 7445), governs
; the usage and introduction Oe additives in unleaded
gasolines and ~pecifically provides that no fuel or
fuel addltive may be first introduced into commerce
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1310832
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that is not ~substantially similar" to any fuel or
fuel additive used in the certification of any 1974 or
later model year vehicle. In July 1981, EPA defined
substantially similar" to include fuels with up to
2.0 wt. percent oxygen. Ethers or alcohols (except
methan~l~ are acceptable additlves if they otherwlse
meet these oxygen limitations. Methanol can be used
as a de-icer when used up to 0.3 volume percent or be
used for this purpose up to 2.75 volume percent when
introduced with an equal volume of butanol or a higher
molecular weigh~alcohol. However, the fuel must
confor,m to the characteristics of an unleaded gasoline
as specified by ASTM D 439. This definition of
"substantl~lly similar" provides a general rule eor
the inclusion of oxygenates in unleaded gasolines.
Methyl tertlary butyl ether ~MTBE) gualieles under the
general 2& oxygen rule. This ls equivalent to about
~ MT8E by volume, depending on the specific gravity
; ; Oe the gaso}ine.
The Clean Air Act under Section 211(f)(4) peovides
that the EPA Admini~trator may waive the prohlbition
on new fuels or fuel additives. However, prior to
granting a walver the Administrator must determine if
the application meets the burden o demonstrating that
the new fuel or fuel additive will not cause the
failure of an emission control system or an emission
standards~s). ~nder this section of the Act, the
Administrator has both denied and granted several
waiver requests.
The EPA has denied all previous waiver requests
involving MMT in unleaded gasoline. The EP~ denied
Ethyl Corposation's MMT waiver applications because
Ethyl failed to demonstrate that MMT at its proposed
concentration levels of 1/16, 1/3~ and 1/64 gram per
gallon oP gasoline would not cause or ultimately cause
unacceptable hydsocarbon emissions. See generally
Environmental Protectlon ~gency in RE Applications for
MMT Waiver, Federal Reglster~ ~ol. 43, No. 181,
Monday, September 18, 1978, and Ethyl Coep; Denial of
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Application for Fuel Waiver; Summary of Decision,
Federal Regl~ter~ Vol. 46, ~o. 23n, Tuesclay, Dec. 1,
1981.
The EPA has also denied several waiver requests
for alcohol additives. However, on Septembee 23,
1981, Anafuel Unlimited was granted a waiver for a
proprietary fuel called ~Petrocoal" ~see generally the
Petrocoal Waiver and Supporting Docket EN 81-8).
~Petrocoal" is a mixture of methanol and certain
four-carbon alcohol~ ln unleaded gasoline in the
presence of a proprietary corrosion inhibitor. The
fuel can contain up to 12 volume percent methanol ancl
up to 15% total alcohols. The ratio of methanol to
four-carbon alcohols cannot exceed 6.5 to 1. The fuel
must meet A5TM D 439 specifications.
The EPA granted on November 16, 1981 a request by
ARCO for a waiver for mixtures Oe methanol and
gasoline-grade tertiary butyl alcohol "GT~" (s&e
generally the Oxinal Waiver granted in the EPA and
Supporting Docket EN-81-10). ARCO markets these
mixtures under the name "Oxinol~. The ratio of
methanol to GTBA cannot exceed 1 to 1, and the
concentration of oxygen in the finished fuel cannot
exceed 3.5 weight percent. The 3.5% oxygen limit
translates into about 9.6~ by volume. The lower the
methanol content, the greater the total alcohol volume
allowable. At zero methanol content, the 3.5 weight
percent o~ygen is equivalent to about 16 volu~e
percent GT~A.
In 1979, EPA granted a waiver ~or "gasohol", which
contains 10 volume percent ethanol (see generally the
Gasohol Waiver). ~owever, the general rule oF 2
weight percent oxygen would limit ethanol to about 5.5
volume peraent. T~is left an "illegal" limit between
the 5.5 and 10 percent levels. In 1982, EPA i~
interpreted the "gasohol" waiver to include any amount
up to 10 volume percent anhydrous ethanol in unleaded
gasoline.
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The above described legal limitations also follow
from the physical properties of such alcohol gasoline
; compositions, e.g., vapor pressure, enleanment, and
evaporative emissions which can be adversely affected
by the presence of lower molecular weight alcohols
such as methanol and ethanol.
- For example, methanol is 50 percent by weight
oxygen. This leads to a potential problem known in
the art as "enleanment". Fuel introduction and
delivery systems (e.g., fuel injection systems,
carburetors) are 'designed and adjusted to provide a
predetermined stoichiometric amount (ratio~ o~ alr to
fuel, and henae the amount of oxygen to fuel. In fuel
carburetors and in cars without oxygen sensing devices
~his predetermined stoichiometrlc ratio ls calculated
- without regard for gasolines containing oxygen. If a
- gasoline contains excessive concentrations of
oxygenated components such as methanol, the air
(oxygen) to fuel ratio is significantly changed from
`20 the predetermined ration Signiflcation deviations
from the predetermined ratio causes poor ignition and
combustion properties of the fuel. A high air
(oxygen) to fuel ration produced in this manner will
cause the engine to run lean. Ie an engine's air
~oxygen) to fuel ratio becomes too high or lean, the
engine will fail to start and/or continue to run.
In ef~ect enleanment sets a technical limit on the
total amount of any oxygenated component such as
alcohol that can be incorporated into a gasoline
without making ma~or modifications to most fuel
introduction and delivery systems. Moreover, higher
air (oxygen) to fuel ratios also may contribute to the
; production o~ certain environmentally harm~ul nitrogen
. oxides.
~n attribut~ of enleanment which heretofore has
;~ not b~en distinguished by those skilled in the art is
called "technical enleanment~. "Technical enleanment"
`, is that unexpected phenomena which exhibits symptoms
of enleanment occurring when the total air ~oxygen)
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content of the finished fuel is not stoichiometrically
or chemically lean. Such behavior is very similar to
enleanment and includes engine stalling, lack of
power, poor combustion, difficult start-ups
(e~peclally warm start-ups) and other problems
normally assoclated wlth alcohol/gasoline fuels and
combustion/fuel systems which are known to be
chemically or stoi~hiometrically :Lean. The dif~erence
between chemical or stoichiometric enleanment and
"technical enleanment" is that traditional chemical or
stoichiometric enleanment can be predicted from a
chemical and/or stoichiometric basis, whereas
- ~technical enleanment" iB not predictable on the same
basis.
Since the EPA has exclusive ~urisdiction of
unleaded gasoline additlves, exhaust emissions are a
ma~or concern when incorporating alcohols into
unleaded gasolines. Numerous studies on this subject,
including prior EPA waiver appllcations for alcohol
additives, exist in the literature. These studies
generally show that carbon monoxide emissions are
reduced, and that nitrogen oxide emissions are
generally unch~nged. ~ydrocarbon emissions from such
fuels generally vary. For example Appendix 8 of the
EPA's Walver ~or ~Petrocoal~ showed the fuel's
hydrocarbon emissions to be unchanged, see Federal
Register Vol~ 46, No. lg2, Monday, 10/5/81, Page
48978. However, in one of the more comprehensive
studies on the sub~ect prepared under the direction of
the U.S. Energy Research and Development
Administration, hydrocarbon emissions increa~ed with
the introduction o~ methanol. Hydrocarbon emissions
increa ed further by increasing the methanol
concentrations in ,the base gasoline. See J.R. Allsey,
EXPERIMENTAL RESULTS USING METHANO~ AND
METHANOL/GASO~INE BLENDS AS AUl'OMOTIVE ENGINE FUEL,
Bartlesville Energy Research Center, Bartlesville,
OkIahoma ~1977~. ~
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rrhereforel in view of the federally mandated ban
on methyl cyclopentadlenyl manganese tricarbonyls
(MMT~, the phase-out of leaded gasolines, and in
further view of the above noted technical and legal
problem~ associated with gasoline/alcohol blends,
there now exist~ a very presslng need to find new
families of environmentally safe antiknock agents
and/or learn to use known antiknock agents in ways
which are technically and environmentally acceptable.
Applicants believe that the latter course holds the
be3t immedia~e promise.
:
SUMMARY OF 'rH~ INVENTION
; Applicants believe that the unacceptable
hydrocarbon emlssions and other pollution problems
associated with the use of cyclomatic manganese
tricarbonyls such as MMT are directly traceable to the
associative build-up of unoxidized or partially
oxidized hydrocarbons and the oxide of manganese
( ~M11304 n ) ~ The oxide of manganese is the
oxidation product of the cyclomatic manganese
tricarbonyls. Although the exact chemical mechanism
of this hydrocarbon/Mn30~ build-up is not
fully understood, appllcants believe that it begins
with the formation of a hydrocarbon gum material
~nHGMn) comprised chiefly of unoxidized or partially
oxidized hydrocarbons and Mn304 It is
believed that once formed, the HGM tends to attract
other unoxidized or partially oxidized hydrocarbons
and Mn304 which together tend to plug
catalysts, foul spark plugs and form combustion
chamber deposit~. It is also believed, especially
when the quantitle~ of MM~ are in excess of about 1/16
g manganese per gallon, that the presence of HGM
cau~es a certaln type of Mn304 deposit in the
catalytic converter 3ystem which ultimately causes it
to plug.
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~ pplicants have discovered that certain beneficial
chemical reaction(s) unexpectedly occur when
organomanganese containing unleaded gasolines are
combined with Cl to C6 aliphatic alcohola such
that the resultant novel fuel composition can be made
to meet current federal hydrocarbon emission
standards. This novel fuel composition can become
eligible for EPA waivers of the type noted above which
hecetofore have been denied due to potential catalyst
plug~ing and excessive hydrocarbon emissions. The
beneficial effect of this novel fuel is achieved by
the use of certain well-defined proportions of C
to C6 aliphatic alcohols, and well-defined
proportions of cyclopentadienyl manganese tricarbonyl
antiknock agents and nonleaded gasoline bases.
Applicants have further discovered that usage of
the well-defined proportions of cyclopentadienyl
manganese tricarbonyl antiknock agents in unleaded
gasoline bases together with the well-defined
proportions of Cl to C6 aliphatic alcohols ~n
a manner more fully described below, unexpectedly
alleviates and corrects the phenomena of ~technical
enleanment~.
No blending stabilizers ~other than the disclosed
cosolvents needed when methanol is employed) are
required when these three ingredient categories are
combined in appIicants' defined proportions.
Cosolvents are added when methanol is used to insure
the phase ~tability of the fuel composition.
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Therefore, in accordance with a first aspect of the
present invention there is provided a fuel composition
for spark-ignited internal combustion ~engines comprising
a mixture of a nonleaded gasoline base comprised of
hydrocarbons boiling within the gasoline range, with the
non-leaded gasoline base representing from about 70.0 to
about 99.9 volume percent of the fuel composition. A
cyclopentadienyl manganese tricarbonyl antiknock
compound having a manganese concentration from about
0.001 grams to about 2.0 grams of manganese per gallon
of the fuel composition; and a lower molecular weight
aliphatic alcohol solvent selected from the gr OUp
consisting of Cl to C6 alcohols, including mixture
thereof, in a concentration from about 0.1 volume
percent to about 30.0 volume percent of the fuel
composition.
In accordance with a second aspect of the present
invention, there is provided a method for reducing
hydrocarbon emissions and controlling technical enlean-
ment employing a spark ignited internal combustionengine and exhaust system, designed for nonleaded fuels.
The method comprises mixing a nonleaded gasoline base
comprised of~ hydrocarbons representing from about 70.0
to about 99.9 volume percent of the fuel composition
C l~ f e ~ 1' e n ~ /
with a -cyclom~t~4~ manganese tricarbonyl antiknock
compound having a manganese concentration from about
0.001 to about 2.0 gram of manganese per gallon o~ the
fuel composition; and a solvent, including mixtures
thereof, selected ~rom the group consisting of Cl to C6
aliphatic alcohols in a concentration from about 0.1 to
about 30.0 volume percent o~ the fuel composition; and
combusting the resultant fuel composition in a spark
ignited internal combustion engine and emitting the
resultant emissions through an exhaust system.
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DESCRIPTION OF THE DRAWINGS
Figure I plots temperature versus percentage of
distillate recovered for various fuel blends and
graphically depicts the concept of technical enleanment.
Figure 2 plots engine out hydrocarbon ernissions
(EOHC) (g/mi) versus manganese concentration (g/gal.) in
various fuel blends.
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DETAILED D~SCRIPTION OF T~ INVEN~ION
1. ~OA~
The defined range of proportions over which the
gasoline bases, the Cl to C6 aliphatic alcohol
component, and the cyclopentadienyl mangane~e
tricarbonyl component may be amployed to reduce
hydrocarbon emission~, and control technical
enleanment are: .,
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:i TAaL8 OF I~GR~DIENT RANG~S
10 Unleaded base95-99.9 92-95 70-92
Gasoline ~Vol.%)
C to C6 alipha- ;
t~c alcohols0.1-5.0 S.0-8.0 8.0-30. n
~vol.~)
15 2~ by weight*0.05-2.4 0.7-3.8 1.2-14.2
Methyl Cyclopentadienyl
mangançse tri-** -1.0 ** -1 7/8 ** -2.0
carbonyl (MMT) .
: (grams/manganese/
~o gallon
*including cosolvents, if any.
r . *~ = 1/1000 gram.
.
Generally, within these ranges, the hlgher the
total concentration of the lower molecular weight
alcohols (particularly methanol, ethanol and propanol
-~ . in order of their preference) the higher the preeer~ed
~: ~ concentrations of manganese. With manganese
concentratlons of 1/8 gram in the fuel composition the
beneficial EOHC effec:t generally does not begin to
occur until approximately 2~ by voIume of the C
to C6 alcohol component is introduced into the
fueI compo~ition.
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It i9 recommended ln normal cases that when
methanol is used as the sole aliphatic alcohol without
the benefit of any cosolventts) it should be limited
to a concentration of about 5 volume percent or less
of the fuel composition.
However, in most cases when methanol is employed
in concentrations ranging fro~ about l t:o about 24
volume percent of the fuel composition, coso1vent(s)
selected from the group consisting of C2 to
Cl2 aliphatic alcohols, C3 to Cl~ ketones
and/or C2 to Cl2 ether~ in concentrations from
about l to about 2U volume percent should also be
employed. The combined methanol and cosolvent
concentration should, howeverr not exceed 30 volume
percent of the entire fuel composition. When the
cosolvent alcohol(s) is selected from t;he group
; consistlng o C~ to C~ allphatic alcoho1s, the
preferred aliphatic alcohol(s) are saturated aliphatic
alcohol( 9 ) .
In the practice of this invention one or more
Cl to C6 aliphatic alcohols, preferablyr
Cl to C6 saturated aliphatic alcohols, must be
employed in the fuel composition. ~he alcohol
component may be any individual alcohol or any
; 25 combination thereof. Mixed alcohol combinations may;; be desirable for enhanclng blendlng octane values and
^ controlling RVP increases. [t is aontemplated in the
practice of this invention that mixed alaohols
produced from the modification of known methanol or
other alcohol catalysts, use of alkali metal oxide
aatalysts, use of rhodium catalysts, isosynthesis
uslng ~alkalized ThO2 aatalysts, modified lurgi
catalyst~, and/or produced from aertain
omerization/~dehydrogenation processes,
olefinic~hydration proae~ses, ~OX0" processes and the
like, are acceptable.
Alcohol mixtures, generally having methanol,
ethanol, propanols, butanols, pentanols and hexanols
in the compo~itlon; whiah by weight peraent of the
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composition decline as the individual molecular weight
of the alcohol increa~es, are desirable. ~n example
of a mixed alcohol composition wherein the lower
molecular weight alcohols have a higher relative
proportion o~ the composition by volume percent than
do the higher moleculae alcohols include: methanol at
approximately 50 weight percent of the alcohol
component, ethanol at approximately 25 weight percent,
propanols at approximately 13 weight percent, butanols
at approximately 6 weight percent, pentanols at
approximately 3 ~eight percent, with hexanols and
other higher alcohols generally representing the
; balance of the alcohol component.
Another example of a desirable alcohol mixture
would include a compositlon wherein the higher
molecular weight alcohols have higher relative
proportions by volume percent of the composition than
do the lower molecular weight alcohols. Still another
example would include a mixed alcohol composition
wherein similar proportions of each alcohol exist by
volume percent in the composition. Mixed alcohol
compositions generally include methanol to higher
alcohol ratios generally varying from about 4:1 to 1:4
weight percent of the alcohol compositions. Those
~ 25 other combinations of alcohol mixtures which
;~ positively effect RVP, octane, distillation
characteristlcs, end boiling point temperatures,
and/or emissions are particularly desirable.
Suitable alcohols for use include methanol,
ethanol, N-propanol, isopropanol, N-butanol,
;`; secondary-butanol, isobutanol/ tertiary butanoll
pentanols, hexanols and the like. As noted in the
Table of Ingredient Ranges, aliphatic alcohols in
ranges from up to about 30.0g by volume with about up
to 14.~ oxygen by weight give good hydrocarbon
emission results when used in unleaded gasollnes. One
percent to five percent oxygen by weight in the fuel
aomposition are, however, more preferred. The
composition should have at least 0.001 grams manganese
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and generally no more than 2.0 grams manganese of a
cyclomatic manganese tricarbonyl compound per gallon.
Preferably, the alcohol employed should be anhydrous,
but alcohols containing small amounts of water can
also be used. Within the prefPrred concentration
range most of the Cl to C6 aliphatic alcohols
are completely miscible with petroleum hydrocarbons
and it is preferred that such alcohols be used in
amounts wlthin their solubility limits. However, if
desirable, an amount of alcohol ln excess of its
solubility can ~e incorporated in the euel by such
~eans, as for example, by use of mutual solvents.
Desirable individual alcohol compositions would
contain up to about 20 volume percent methanol, or up
to about 25 volume percent ethanol, or up to about 25
volume percent isopropanol, or up to about 25 volume
percent normal propanol, or up to about 30 volume
percent tertiary butanol, or up to about 30 volume
- percent secondary butanol, or up to about 30 volume
percent isobutanol, or up to about 30 volume percent
normal butanol, or up to about 30 volume percent
pentanols, or up to about 30 volume percent hexanols,
together ~ith MMT as the cyclopentadienyl manganese in
a concentration of about 0.001 grams to 2.0 gram of
manganese per gallon of fuel composltion. A more
preferred manganese concentration is from about 1/32
to about 1/8 gram of manganese per gallon of fuel
composition.
A desirable fuel composition contains methanol
from about 1 to about 15 volume percent of the
composition, C2 to CB aliphatic alcohols in
concentrations from about 1 to about 15 volume percent
of the composition and a preferred MMT concentration
from about 0.001 ~to about 1/4 gram of manganese per
gallon of fuel composition and a more preferred MMT
concentration from about lf64 to 1/8 gram per gallon.
A preferred fuel composition contains methanol
from about 1 percent to about 9 volume percent of the
composition, C2 to Cg aliphatic alcohols in
- - \
1310832
concentrations from about 1 to about 10 volume percent
of the composition, a MMT concentratlon from about
0.001 to about 1/4 gram manganese per gallon of fuel
compo~ition and a more preferred M~T concehtration
s from about 1~64 to 1/3 gram per gallons.
~ more preferred fuel composition contains
methanol from about 2 to about 6 volume percent with
C3 to C8 aliphatic alcohols in concentration
from about 1 percent to about 10 volume percent of the
composition and a MMT concentration from about 0.001
to about 1/4 gram manganese per gallon Oe fuel
composition and a more preferred MMT concentration
from about 1/64 to 1/8 gram per gallon.
An even more preferred fuel composition would
contain methanol from about 2 to 6 volume percent with
C4 to C6 saturated aliphatic alcohols in
concentrations from about 1 percent to about 10 volume
percent of the composition, partlcularly those having
boiling points higher than tertiary butanol and a MMT
concentration from about 0.001 to about 1/4 gram
manganese per gallon of fuel composition and a more
preferred MMT concentration from about 1/64 to 1~8
gram per gallon.
2. ~orrecting Technical Enleanment
Although the actual cause of "technical
enleanment~ tnT.E.") is not fully understood,
applicants have di~covered that methanol and/or
ethanol gasollne blends are particularly susceptible
to technical enleanment especially in the presence oE
highly volatile, low aromatic, high paraefin, and/or
high mld-range boiling gasollnes. In these case3
applicant~ have qiscovered that technical enleanment
~ symp'oms can be substantially alleviated or even
-~ corrected by the sue of the above noted proportions of
base gasolines, cyclopentadienyl mangane3e tricarbonyl
antiknock compounds and the addition of aliphatic
alcohols and/or cosolvent~s) in the manner described
below.
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An ~nexpected synergism has been discovered when
both MMT and the Cl to C6 aliphatic alcohols,
especially the higher boiling point alcohols, are u~ed
jointly to alleviate and correct the symptoms of T.E.
Applicants are not entirely sure of MMT chemical
mechanlsm. However, it ls believed that MMT when in
combination with the aliphatic alcohols tends to act
as some sort of combustion catalyst improving the
fuels ignition and combustion properties in such a
manner as to alleviate T.E. symptoms.
~nother aspectlwhich Applicant believes influences
technical enleanment is the distillative nature of
alcohol/ga301ine fuels themselves. Lower boiling
point alcohols tend to form azetropes with the lo~er
bolling gasoline components and depress the
temperatures at which the lnLtial and middle fuel
fractions distill. The applicant believe3 that in
certain cases thls depre~sion or displacement becomes
so aggravated as to become a principal factor in T.E.
Figure 1 illustrates the lmproved technical
enleanment aspects achleved by this invention.
Specifically, the tendency of the methanol and~or
; ethanol gasoline blends of this invention to fall lnto
the ~ECHNICAL ENLEAMMENT REGIONn. Flgure 1 also
shows the distlllatlon curve of a base gasoline (the
` ~Base Fuel") with a high mid-range boiling point. It
also shows the base gasoline in combination with a 6
volume percent methanol and 4 volume percent ethanol
mixture, the "Uncorrected Fuel". Note, that the
Uncorrected Fuel mixture having an oxygen content of
approximately 4.4 percent by weight lntrudes into the
TECHNICAL ENLEANMæNT REGION due to the aggravated
- displacement of the lower and mid-range areas of the
distillation curve. This lntruslon is typical of many
', 35 methanol and/or ethanol gasoline mixtures. Figure 1
illustrates the effect of the "Corrected Fuel" by
~, having an oxygen content of approximately 4.3 percent
by wei~ht and prepared by adding an 1/8 gram manganese
of MMT and changing the cosolvent from 4 volume
.' ' ~
~ -16-
.g.
1 3 ~ 08~2
percent ethanol to 6 volume percent normal butanol.
Note that the Corrected Fuel' 9 distillation curve is
above the TECHNICAL ENLEANMENT R~GION. This example
ls illustratlve of the improved technical enleanment
characteristics of fuel compositions of this
invention. Naturally, the various compositions
~- disclosed in this invention do not pos~ess exactly
identical effectiveness, and the most advantageous
concentration for each such compound will depend to a
large extent upon the particular alcohol or cosolvent
used and will also depend to some extent upon the
composltlon of the base gasoline itself.
By correcting the aggravated displacement in the
distillation curve as pre~ented in Figure 1 with the
inclusion of MMT and the higher boiling point alcohols
~cosolvents) in accordance with the Applicant's
described construction, App]icant has discovered a
control for T.E. The combined usage of MMT, Cl -
C6 alcohols ~cosolvents), exhibits a particularly
ameleorative synergism eefectively controlling T.E.
symptoms.
~ his departure fro~ the prior art understanding Oe
enleanment behavior is important to the whole
enle3nment issue. ~'bis is due principally to the fact
th~t methanol and/or ethanol mixtures normally are
mo~e likely to distill out of the gasollne ~ystem
togethee with other lower boiling point gasoline
- substituents where azetropes are are formed prior to
the distillation of the other components of the
gasoline. The early distillation of these alcohol
components means that the oxygen in the fuel is being
distllled off at lower temperatures in the initial
and/or middle fractions of the gasoline and not over
the fuel~ entire volatility range which often results
in poor combu~tion and symptoms of enleanment.
With Applicant's invention, Applicants can
effectively improve combuskion efficiency and spread
the volatility of methanol and/or ethanol mixtures to
match the volatility of the hydrocarbons; thereby
. '
-17-
.
. ,
~ 3l~832
correcting technical enleanment and permitting greater
concentrations of total oxygen to be present in the
fuel mtxture than heretofore would ha~e been
considered practical to those skilled in the art.
Thi~ represents a significant departure from the prior
art. In view of the prior art literature this is
quite unexpected and novel.
3. Reduction of engine Out ~ydrocarbons (~onc)
.
Applicants have discovered that those M~T
concentrations that heretofore have heen considered
excessive for reason3 associated with unacceptable
EOHC emis~ions and possible catalyst plugging, when
combined with the aliphatic alcohols, and unleaded
gasoline bases in accordance with Applicant's noted
proportions and construction, tend to prevent
unacceptable ~OIIC emissions and prevent cataly3t
plugging. In view of the extensive prior art
literature on the subject, this result is also quite
unexpected.
The beneficial hydrocarbon eml3sion effects are
best illustrated in Pigure 2. Figure 2 illustrates
the range of hydrocarbon emissions improvement
expected at 5,000 mile3 using the defined proportions
of Cl to C6 aliphatic alcohols (cosolvents)I
MMT and unleaded base gasolines ~the "Corrected
Fuels"), over fuels just e~ploying MMT concentrations
~ithout the benefit of Cl to C6 aliphatic
alcohols (the nUncorrected Fuelsn). The 5,000 mile
mark reflects the crltical point where the initial
assent in hydrocarbon emissions i5 typically
experienced in MMT containing nonleaded fuels. The
; effect of methanpl and its associated cosolvents,
including eth0rs and ketones, are incorporatea in
Figure 2. Figure 2 illustrates the significant
differences in the hydrocarbon emission beha~ior of
pre-19BO standard model cars (manufactured for under
1.5 gram~ of hydrocarbon emission per mile standards)
'
.; ,
;, .
,: ,
1 31 0832
.,
uslng the Uncorrectecl Fuel and the Corrected Fuel
formulated in accordance with Applicant's invention.
The methyl cyclomatic manganese tricarbonyls used
in our composition~ can contain such homologes or
substituents as, for example, alkenyl, aralkyl,
aralkenyl, cycloalkyi, cycloalkenyl, aryl and alkenyl
groups. Illustrati~e, but nonlimiting examples of
such substituted and unsubstituted cyclomatic
manganese tricarbonyl antiknock compounds are:
cyclopentadienyl manganese tricarbonyl;
m e t h y 1 c y c 1 o p e n t a d i e n y 1 m a n g a n e 8 e
benzyleyelopentadienyl manganese tricarbonyl;
1. 2-dipropyl 3-cyclohexylcyclopentadienyl manganese
tricarbonyl~ 1.2-diphenylcyclopentadienyl mangane~e
trlcarbonyl7 3-propenylienyl manganese tricarbonyl;
2-tolyindenyl mangane3e tricarbonyl~ fluorenyl
manganese tr icarbonyl t 2.3.4.7 - propy~luorenyl
manganese tricarbonyl; 3-naphthylfluorenyl manganese
; tricarbonyl; 4.5.6.7 - tetrahydroindenyl manganese
tricafbonyl; 3-ethenyl-4, 7-dlhydroindenyl manganese
tricarbonyl; 2-ethyl 3 (a-phenylethenyl) 4,5,6,7
tetrahydroindenyl manganese tricarbonyl; 3 --
~a-cyclohexylethenyl); 4.7 - dihydroindenyl manganese
tricarbonylf 1,2,3,4,5,6,7,3 - octahydrofluorenyl
manganese tricarbonyl and the like. Mixtures of such
compounds can al80 be used. The above compounds can
generally be prepared by metho2s which are known in
the art. Representative preparative methods are
described, for example, in U.S. Patents 2,819,416 and
2,al~,417.
S ince the oxidation product of the above methyl
cyclomatic manganese tricarbonyls, i.e.,
Mri304, plays a leading role in RGM build-up,
it is desirable, to use as little of these methyl
cyclomatic manganese tricarbonyl compounds as 1B
necessary in order to maximi~e the FlGM inhibition
bene~its of the invention. As seen in the Table of
Ingredient Concentratlons, concentrations of the
methyl cyclomatic mangane~e tricarbonyl compound
, '' .
-19-
t 3i ~
concentration3 ~expressed as grams of manganese metal
per gallon of the resulting fuel composition) as low
as 0~001 gram per gallon may be used. However,
concentrations up to and lncluding 2.0 grams manganese
per gallon can be employed, but are le~s preferred.
On occasion, amounts above the recited range can also
be employed, but such concentrations tend to be less
satisfactory.
In terms of economic octane benefits,
concentrations in the range of Erom about 0.00l to
about 2.0 grams manganese per gallon glve good
results, concentrations from about .001 gram to 1/2
gram give better results, and concentrations from
about 1/64 - 1/8 gram/gallon give excellent results
; lS and are more preferred. This invention also
contemplates the use of other additlves! such as
multipurpose additives. Nonlimiting examples include
scavengers, made necessary or desirable to maintain
fuel system cleanllness and control exhaust emisslons
due to the presence Oe the organo-manganese compound
- in the fuel.
. Using Cosolvents
'
When methanol is used as the aliphatic alcohol of
choice, it is desirable that a cosolvent should also
-~ 25 be employed to insure phase stability of the fuel
composition to the extent that the fuel composition
~; containing methanol and approximately 500 parts per
- million water will not phase separate at 15F, or the
lowest~temparature to which the fuel composition will
be exposed. GeneraIly speaking the methanol to
~,. cosolvent ratio should not exceed about 5 parts
methanol to 1 part cosolvent depending upon the nature
of the base fuel and the cosolvent(s) used.
: The cosolvent~s) can be selected from the group
consi~ting of C2 to C12 aliphatlc alcohols,
C 3 t o Cl 2 ke to n e 8 an d /or C 2 to Cl 2
:. :
-20-
. . .
i, .
,~
3 2
ethers. Within the SGOpe of this invention it is
contemplated that these cosolvents may also be used
with any Cl - C6 aliphatic alcohol, e3pecially
in cases where corrosion, phase stability or vapor
pressure become an issue. It is also within the scope
and teaching of this invention to employ one or ~ore
alcohols, ketones or ether~ as cosolvents or any one,
two or all three cosolvents classes o~ this invention
~imultaneously.
It iB further contemplated/ within the scope oE
; thi~ invention, in cases where vapor pressure or
evaporatlve emission3 are a concern, especially when
Cl to C3 molecular weight alcohols are used
individually or in combination, to employ C2 to
C7 ethers lndividually or in combination with each
other wlth or without other cosolvents.
It i~ also within the scope and practice of thls
invention to uae mixed cosolvents, including mlxed
; alcohols, ethers and/or ketones as cosolvents. It ha~
been found that mixed cosolvent alcohols partlcularly
t ho s e in th e C 2 to Cg range have an
ameleoratlve effect on both RVP and octane blending
values,
In accordance with the discussion o~ cosolvents
wlthin thls invention with regard to phase stability,
; the prefere~d cosolvent class rankings would be
alcohols first, ketones second, and ethers last.
Also, the bigher the average boiling point of the
; aosolvents employed within a particular class, up to a
CB aosolvent, the greater the preeerence. Wlth
cosoivents greater than C~ the reference is
reversed so that a Cg cosolvent would be preferred
over a Clo aosolvent and so forth.
Wlthln the ~sub-categories of the partlcular
cosolvent class, after preference is glven to the
alcohol, ketone and ether ranklng, and after
preference is~ given to the average bolling point
characterlstics, then preference would be glven the
i,
-21-
' ".~
32
.
,
branched chain molecules over straight or cyclical
chained molecule~.
The alcohol cosolvents will have from two to
twelve carbon atoms. The preferred cosolvent alcohols
5 are saturates ha~ing high water tolerances and high
bolllng points. Representativ~ alcohol cosolvents
include ethanol, isopropanol, n-propanol, tertiary
; butanol, 2-butanol, isobutanol, n-butanol, pentanols,
amyl al~ohol, cyclohexanol, 2-ethylhexanol, Purfuryl
10 alcohol, iso amyl alcohol, methyl amyl alcohol,
tetrahydrourfury~ alcohol, hexanols, cyclohexanols,
furon~, septanols, octanols and the like. The alcohol
cosolvents, in reverse order o~ their preference, are
propanols, butanols, pentanols, hexanols and the other
15 higher boiling point alcohols. The more preferred
alcohol cosolvents include isobutanol, n-butanol,
pentanol and the other higher boiling point alcohols.
The ketones used as cosolvents in fuel
compositions taught herein will have from three to
20 about twelve carbon atoms. Lower alkenyl ketones are,
however, slightly preferred. Representative lower
alkenyl ketones would include diethyl ketone, methyl
- ethyl ketone, cyclohexanone, cyclopentanone, methyl
isobutyi ketone, ethyl butyl ketone, butyl isobutyl
` 25 ketone and ethyl propyl ketone and the like. Other
ketones include acetone, diacetone alcohol, diisobutyl
ketone, isophorone, methyl amyl ketone, methyl isamyl
ketone, methyl propyl ketone and the like. A
representative cyclic ketone would be ethyl phenyl
30 ketone.
Representative ethers which can be used as
cosolvents in ~uel compositions taught herein will
have from 2 to about 12 carbon atoms and would include
the preferred methyl alkyl t-butyl ethers such as
~ ~ 35 methyl tert-butyl ether, ethyl tertiary butyl ether,
; ~ also preEerred tertiary amyl methyl ether, dialkyl
~ther, isopropyl ether, di methyl ether, diisopropyl
ether, diethyl ether, ethyl n-butyl ether,
-22-
.
,.
~.
1 31 0832
ethylidenedimethyl ether, butyl ether, and ethylene glycol
dibutyl ether and the like. The representative straight
ethers which can be used in the fuel blends of this
invention would include straight chain ethers such as
those presented above. Less preferred are cyclic ethers
wherein the ether's oxygen molecule is in a ring with
carbon atoms. For example, 4,4-dimethyl-1, 3-dioxane,
tetrahydrofuran~, such as, for example,
2-methyltetrahydrofuran, 2-ethyltetrahydrofuran, and
3-methyltetrahydrofuran may also find use in the present
invention. The most preferred ether would be a branch
chained ether. In order to be most advantageously
employed, the above ethers should also be readily soluble,
either directly or indirectly in the gasoline.
Generally, the preferred methanol/cosolvent ratio
will range from 0.5 to 3 parts methanol to 1 part
cosolvent, Ratios from about 3 to S parts methanol to
1 part cosolvent are also preerred in certain
circumstances. The ratio o~ methanol to cosolvent can
exceed S to 1 or be less than 0.5 to 1. However
methanol/cosolvent ratlos outside these ranges are
normally less desirable unless vapor pressure or
technical enleanment are issues in the fuel
formulation. The methanol to cosolvent ratios will
gener~lly be higher when a higher boiling point
aliphatic alcohol up to C8 is the cosolvent ar.d lowest
when ethanol is the cosolvent. In the same sense
methanol to cosolvent ratlos are higher with alcohols,
than they are with ketones, than they are with
ethers. That is to say, when a comparable higher
boiling point or molecular weight alcohol~ ketone or
ether is compared, the highest ratio (within the
general range of 3 to 5 parts methanol to 1 part
cosolvent) is permissible when the cosolvent i9 an
alcohol, the second highest ratio when the cosolvent
is an alcohol, the second highest ratio when the
cosolvent is the ketone and the lowest ratio when the
cosolvent i9 an ether.
~_J -23-
131083~
For example, in compar ing normal-butanol, CH
~ C H 2 ) 2 C 1l 2 0 H; d i e t h y 1 e t h e r,
( C 2 H 5 ) 2 0; and me thyl ethy 1 ke tone
CE13COI C~32 CH3; the preferred ratios might
be 3 to 5 parts methanol to 1 part N-butanol, 1 to 2
parts methanol to 1 part methyl ethyl ketone, and
part methanol to 2 to 3 parts diethyl ether. Within
each of these cosolvent groups, the methanol-cosolvent
rai:ios ~hould be at their highest when higher
molecular weight molecules ~e.g., C~ - C12)
are used. ~ ~
- It is also within the scope and practice of this
invention to utili~e individual and~or different
molecular weight cosolvent mixtures, higher alcohol
mixtures ~especially C4 - C12 in varying
combinations and concentration) together with aromatic
hydrocarbons as a means of controlling RVP and
technical enleanment.
5, ormulatin~ the Cl - C6 Allphatic
Alcohol and/or Cosolvent Component
In formulating the desired alcohol ~cosolvent)
componcnt~ and determining the preferred ratio of
methanol to cosolvent~s) the following factors sho~ld
be taken into consideration:
(1 ) Th& base gasoline composition.
~2) The distribution system whlch the
finished fuel will be exposed to.
(3) The average age of the vehlcular
population consuming the fuel.
~4) The fuel's propensity towards technical
enleanment .
~5) The f,uel's efeect on EOHC.
Generally the more desirable the base fuel
compositlon as described hereafter, the less
35 restrictiva the formulation and construction of the
.
-24-
.
~ ~ ~s~
1 31 0~
Cl to C6 aliphatic alcohol (cosolvent)
component. The more desirable the base gasoline/ the
lower can be the average boiling point of the alcohol
~cosolvent) component. The more desirable the base
S gasoline the greater the permissible percentage oxygen
- by weight that can be contained in the finished fuel.
- The more desirable the base gasoline the greater the
flexibillty in reducing or increasing the total
percent alcohol by volume in the finlshed fuel.
For example, the higher the aeomatic content of
the base gasoline''the higher the permissible methanol
to cosolvent ratio, and the lower the required average
boiling polnt of the alcohol ~cosolvent) component.
Inversely, a less desirable base gasoline with lower
percentages of aromatic co~ponents generally will
require a lower methanol to cosolvent ratio and a
higher average boiling point alcohol ~cosolvent)
component. This same low aromatic gasoline will limlt
the flexibility of reducing or increasing the total
volume of the alcohol component. It i9 likely that
the alcohol component as a percent of volume would be
easier to increase then it would be to decrease.
As discussed above azetropic relationships
aggravate the alcohol (cosolvent~ component
configurations as well. Particular attention must be
given to the characterlstlcs of technical enleanment.
~;; Generally in gasolines with higher mid-range
volatility and/or higher paraffinic content, the
methanol to cosolvent ratios are lower, sometimes less
than 1. In these cases the required average boiling
point of the alcohol lcosolvent) component is normally
higher, and the flexibility of either increasing or
; reducing the total alcohol ~cosolvent) component is
restricted. The permissible oxygen content is
normally reduced and in ome severe cases it should
not exceed 2.5~ by weight. In these base gasolines it
is important to construct the alcohol (cosolvent)
component so as to prevent any siqnificant
' .
-25-
131~J832
di#placement of the lower and particularly the
mid-range gasoline fractions during distillation. It
is desirable to construct the alcohols (cosolvents)
volatility (distillation) to match the hydrocarbons
volatility as closely as possible to cover the largest
portion of the distillation curve.
In addition to considering the base gasoline to
which the alcohol (cosolvent) component is added,
consideration must also be given to the fuel
distribution system to which the ~inished fuel will be
exposedO The greater the likelihood of significant
: exposure to moisture, temperature variations and cold
weather conditions, the more restrictive will be the
alcohol (cosolvent) component construction and the
higher should be the total alcohol percent by volume
and the lower the alcohol cosolvent ratio wllich is
contained in the fuel.
For example, a methanol to cosolvent ratio of 3 to
1 using isopropanol as the cosolvent, together with
the alcohols representing 7 percent by volume of the
fuel, would normally he acceptable if the fuel were to
be distributed in a dry 3ystem averaging ~0F.
However, if it were anticipated that the fuel would be
expo~ed to 20F temperatures, or to greater
concentrations of moisture or water, then certain
adjustments would have to be made. One or more of the
following ad~ustments would be required:
(a) The methanol to cosolvent ratio~ would be
reduced to 2 to 1, or 1 to 1, increasing the
average weight of the combined alcohol
(cosolvents) component.
(b) The cosolvent would be changed from
isopropanol to a butanol or higher boiling
point alcohols.
~c) The volume of alcohols (cosolvents) would be
;` increased from 7 percent to 12 percent.
-26-
' '
. ~
t ~
The age of the vehicular population which consumes
the flnlshed fuel also impacts the amount of oxygen
which may be contained in the fuel. In the case of
older automobiles the finished fuel may contain
up~ards to 5-7 percent total oxygen by weight. Those
newer automobiles using 3-way catalysts which require
more stringent air fuel ratios are limited to
generally 4-5 percent total oxygen by weight. New
vehicles containing oxygen sensing devices may use
fuel3 containing upwards of 7 percent oxygen by
~ weight. With the anticipated improvements of oxygen
: sensing devices in 198S and future model years, the
oxygen content of the finished fuel could approach 12
percent or more be weight.
In an effort to minimize the e~fect oE EOHC and
increase the anti-knock concentrations of MMT one
should employ the maximum concentrations p~ssible of
Cl to C3 alcohols. The highest preference is
given to methanol, the second to ethanol and the third
20 to propanol
6. Unleaded Base Gasollne Composition
The nonleaded or unleaded gasoline bases in
Applicants' fuel composition are conventional motor
fuel di3tlllates boiling in the general range of about
25 70 to 480F. q'hey include substantially all grades
of unleaded gasoline presently being employed in spark
ignition internal combustion engines. Generally they
contain both straight runs and cracked stock, with or
without alkylated hydrocarbons, reeormed hydrocarbons
30 and the llke. Such gasolines can be prepared from
saturated hydrocarbons, e.g., straight stocks,
alkylation products and the like, with detergents,
~ antioxidants, dibpersants, metal deactivators, rust
; inhibitors, multi-functional additives, demulsifiers,
35 fluidi~er oils, anti-icing, combustion catalysts,
corroslon inhibitors, emulsifiers, sur~actants,
:
-27-
1310~
sol~ents or other similar and known additives. It is
contemplated that in certain circumstance~ these
additive3 may be included in concentratlons above
normal levels.
Generally, the base gasoline will be a blend of
stocks obtained from several refinery processes. The
final blend may also contain hydrocarbons made by
other procedures such as alkylates made by ~he
reaction of C~ olefins and butanes using an acid
catalyst such as sulfuric acid or hydrofluoric acld,
and aromatics made,from a reformer.
The olefins are generally formed by using such
procedures as thermal cracking and catalytic
cracking. Deyhydrogenation oE paraefins to oleflns
can supplement the gaseous olefins occurring in the
refinery to produce feed material fo either
polymerization or alkylation processes. The saturated
gasoline component~ comprise paraffins and
naphthenates. These saturates are obtained from:
~1) virgin gasoline by distillation ~straight run
gasoline), (2) alkylation processes (alkylates), and
(3) isomerization procedures (conversion of normal
paraffins to branched chain paraffins of greater
octane quality~. Saturated gaRoline components also
OCCUt in so-called natural gasolines. In addition to
the foregoing, thermally cracked stocksl catalytically
cracked stocks and catalytic reformated contain
saturated components. Preferred gasoline bases are
those having an octane rating of (~ + M~/2 ranging
from 78-95. It is desirable to blend the gaaoline
base so that the minimum aromatic content is no less
than lS~ and preferably greater than 20~. The
gasoline base should have an olefinic content ranging
from 1% to 30%" and a saturate hydrocarbon content
ranging from about 40 to 80 volume percent.
The motor gasoline bases used in formulating the
fuel blends of this invention generally have initial
boiling points ranging from about 70F to abo~lt 115F
-28-
.. .
t~o~
and final boiling points ranging from about 380DF to
about 480F as measured by the standard ASTM
distillation procedure (ASTM D-86). Intermediate
gasoline fractions boil away at temperatures within
these extremes.
Table 1 illu3trates the hydrocarbon-ty~pe makeup of
a number of preferred fuels which can be used in this
invention.
TA~LE I
. .
Hydrocarbon Blends of Pceferred Base
Fuels--Volume Percentage
Fuel AromaticsOlefins Saturates
, ;
A 35.0 12 0 73.0
~ 40.0 11.5 48.5
C 20.0 22.5 57. 5
D 33.5 10.0 55. 5
E 36.5 5.0 58.5
F 43.5 21. 5 35 . O
; G 49.5 2.5 48.0
In terms of phase stability and water tolerance,
desirable base gasoline compositions would include as
many aromatics with C8 or lower carbon molecules
as possible in the circumstances The ranking or
aromatics in order of their preference would be:
benzene, toluene, m-xylene, ethylbenzene, o-xylene,
isoproplybenzene, N-propybenzene and the like. After
aromatiGs the neXt preferred gasoline component in
~ terms of phase stability would be oleins. The
;, ranking Oe preferred olefins in order of their
-~ 30 preference would be7 2-methyl-2-butene, 2 methyl-l
butene, 1 pentene, and the like. However, from the
~;
:f
-29-
~- : - . ,
13~8`~2
standpoint of minimizing the high reactivity of
olefins and their smog contributing tendencies,
oleflni~ content must be closely watched. After
olefins the least pre~erred gasoline component in
terms of phase stability would be paraffins. The
ranking oE preferred paraffins in order of their
- preference would be; cyclopentane, N-pentane, 2,3
dimethylbutane, isohexane, 3-methylpentane and the
like.
In terms of phase stability, aromatics are
generally preferred over olefins and oleflns are
prefereed over paraffins. Within each specific class
the lower molecular weight components are prefereed
over the higher molecular weight components.
It is also desirable to utilize base gasolines
; having a low sulfur content as the oxides of sulfur
tend to contrlbute to the irritating and choking
characteristics of smog and other eorms Oe atmospheric
pollution. To the extent it is economically feasible,
the base gasolines should contain not more than about
O.l welght percent of sul~ur in the ~orm of
conventlonal sulfur-containing impurities. Fuels in
which the sulfur content is no more than about 0.02
weight percent are especlally preeerred for use in
this invention.
The gasoline bases of this invention can also
contain other high octane organic components.
Nonlimit~ng examples include phenols (e.g., P-cresal,
2,~ xylenal, 3-methoxyphenal), e~ters (e.g., isopropyl
acetate, ethyl acrylate) oxides (e.g., 2-methylfuran1,
ketones (e.g., acetone, cyclopentanone), alcohols
(furon, furfuryl), ethers (e.g., MTBE, TAME, dimethyl,
diisopropyl), aldehydes and the like. See generally
nAre There Substitutlons For Lead Anti-Knocks?",
.
Unzelman, G.H., Forster, E.J., and Burns, A.M., 36th
Pefinlng Mld-Year meeting, American Petroleum
Institute, San Francisco, California, May 1~, 1971.
'~
-30-
,~ ,
~3~08~
~ ;
.
The gasoline bAses which this invention employs
should be lead-free or substantially lead-free.
j However, the gasoline may contain antiknock quantities
i; of other agents such as cyclopentadienyl nickel
~ 5 nitrosyl, N-methyl aniline, and the like. Antiknock
:! promoters such as 2.4 pentanedione may also be
included. On certain occasions it will be desirable
for the gasollne to contain supplemental valve and
valve seat recession protectants. Nonlimiting
examples include; boron oxides, bismuth oxides,
c e r am 1 c bo n~ ed Ca F 2~ ir o n phosphate,
tricresylphosphate, phosphorus and sodium based
additives and the like. The fuel may further contain
antioxidants such as 2,6 di-tert-butylephenol,
2,6-di-tert-buyl-p-cresol, phenylenediamines such as
N - N 1 - d i - s e c - bu ty 1 - p- ph ey 1 en ed ia m in e,
N-isopropylphenylenediamine, and the like. ; Likewise,
the gasoline may contain dyes, metal deactivators, or
other additive~ recognlzed to serve some useful
purpose. The descriptive characteristics of one
common base gasoline is given as example 2. Obviously
many other standard and specialized gasolines can be
used in Applicants' fuel blend.
~,
-31-
.
`~
131Q~3
i
EXAMPLE 2
C8ARAC~ERISTICS OF BASE GASOLIN
Reid Vapor Pressure, p9i7.2
: API Gravity Q 60F 64.4
AST~ Distillation
Vol % Evaporate Temp., F.
.
IBP 86*
115
132
; 10 15 1~5
' 157
178
197
213
229
250
286
353
391
:, 20 EP 4~8
Lead Content, g/gal0.005 (or less
and preferably
.none)
Sulfur Content, wt ~ 0O04
Research Octane Number91.5
Motor Octane Number 83.9
Component Vol.
Palraffins 59.03
Olefins 5.01
Naphthenes 6.63
~romatics~ 29.33
; : 30 Average Molecular Weight101.3
~ .
i It i3 contemplated that the fuel composition of
this invention ma~ be used in spark-ignited internal
' combuation engine3 which operate on speciality oils
: ~. which are formulated to suit the general combustion
:~ ~ 35 and other characteristics of the fuel. The fuel
~ : compo~ition of this invention can generally be
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~ , -32~
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1310832
prepared by adding the cyclopentadienyl manganese
- antiknock compound, the Cl to C6 alcohols and
the cosolvents, if any, to the base gasoline with
sufficient agitation to give a uniform composition to
the finlshed euel. ~t is essential in the practice oE
this invention only that the novel combination of
additives, a cyclopentadienyl manganese tricarbonyl
and the Cl to C6 alcohols (with cosolvents, if
- any) be present in the defined-proportions with
unleaded gasoline bases immediately prior to
vaporization and combustlon of the fuel in the
engine. Accordingly, it is withln the scope of thi~
invention to add the components to the base fuel
e$ther separately in any sequence, or as a mixture
wlth each other, so long as the foregoing requirement
is met.
Those skllled in the art will appreciate;that many
variations and modifications oE the invention
disclosed herein may be made without departing from
the spirit and scope thereof.
Thu~ ha~ing disclosed our invention, we claim:
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