EP0086049B1

EP0086049B1 - Compositions for use in alcohol and alcohol containing fuels

Info

Publication number: EP0086049B1
Application number: EP83300294A
Authority: EP
Inventors: Thomas Robert The Lubrizol Corporation Hopkins
Original assignee: Lubrizol Corp
Current assignee: Lubrizol Corp
Priority date: 1982-02-03
Filing date: 1983-01-20
Publication date: 1986-12-17
Also published as: BR8300416A; JPH0238120B2; ES8403435A1; AU1082583A; IN158027B; AU563150B2; CA1208236A; DE3368438D1; MX163254B; EP0086049A1; MX174305B; ZA83684B; ES519483A0; JPS58134192A

Description

Field of the invention

This invention relates to fuel compositions comprising alcohol or alcohol containing normally liquid hydrocarbon fuels, and a corrosion inhibiting composition.

Background of the invention

Alcohol fuels and alcohol containing normally liquid hydrocarbon fuels for use in spark-ignited and compression-ignited internal combustion engines possess a high degree of corrosive activity. This high activity is generally attributed to the presence of acidic and halogen ion containing contaminants present in alcohols but not present in normally liquid hydrocarbon fuels. These alcohol contaminants are particularly distructive to various non-ferrous metals and metal coatings such as tin/lead alloy coatings (i.e. terne coatings) employed on internal surfaces of fuel tanks and fuel lines and to zinc/aluminum metal alloys employed in the construction of carburetors. As a result motor vehicles employing alcohol and alcohol containing normally liquid hydrocarbon fuels have shown a greater propensity toward corrosion in the fuel tank, fuel line and fuel induction system areas.
As is well known, many patents exist which disclose various corrosion inhibiting additives for use in normally liquid hydrocarbon fuels. See, for example, U.S. Patent No. 2,993,771 which relates to a process for preventing deposit formation and corrosion of internal combustion engines from substantially hydrocarbon fuels and particularly gasoline, by the addition of additives to such fuels. Two patents which are specifically directed to corrosion inhibition in alcohol or alcohol containing hydrocarbon fuels, e.g., gasohol, are U.S. Patent Nos. 4,282,007 and 4,282,008. In the former are disclosed additives comprising the reaction product of aminotriazoles and polyisobutenyl succinic acid anhydride and in the latter reaction products of an aminotriazole, isatoic anhydride and N-alkylpropylene diamine.
We have now found that certain reaction products of substituted succinic acylating agents and monoamines may be used as corrosion inhibiting additives in alcohol and alcohol containing normally liquid hydrocarbon fuels. The invention therefore provides alcohol and alcohol containing normally liquid hydrocarbon fuels having improved corrosion inhibition.

Summary of the invention

In its broadest sense the present invention relates to fuel compositions comprising a major amount of an alcohol or an alcohol containing normally liquid hydrocarbonaceous petroleum distillate fuel and a minor amount of a corrosion inhibiting reaction product of (A) at least one substituted succinic acylating agent, the substituent on said substituted succinic acylating agent being an aliphatic hydrocarbon based group of 8 to 15 carbon atoms, with (B) at least one monoamine of the formula
wherein R, is an unsubstituted hydrocarbon based radical and R₂ and R₃ are independently hydrogen or unsubstituted hydrocarbon based radicals with the proviso that when R₂ and R₃ are both hydrogen, R, is a radical selected from tertiary alkyl, cycloalkyl, aryl, aralkyl and alkaryl radicals to provide said alcohol and alcohol containing hydrocarbonaceous petroleum distillate fuels with improved corrosion inhibition.
The invention further relates to fuel compositions for use in internal combustion engines comprising (A) a major portion of a fuel containing (i) from 2 to 100 percent by volume of an alcohol containing 1 to 5 carbon atoms and (ii) from 98 to 0 percent by volume of a normally liquid hydrocarbonaceous petroleum distillate fuel and (B) a minor portion of the corrosion inhibiting reaction product.

Detailed description of preferred embodiments

The corrosion inhibiting additives for use in. compositions of this invention are prepared by the reaction an aliphatic hydrocarbon based substituted succinic acylating agent, and a monoamine as defined hereinbelow.
As used herein, the term "hydrocarbon-based" or "hydrocarbon-based radicals" denotes a radical having a carbon atom directly attached to the remainder of the molecule and having predominantly hydrocarbon character. Such radicals include hydrocarbon radicals; that is, aliphatic, (e.g. alkyl or alkenyl), alicyclic (e.g. cycloalkyl or cycloalkenyl), aromatic, aliphatic-and alicyclic-substituted aromatic, aromatic- substituted aliphatic and alicyclic radicals, cyclic radicals wherein the ring is completed through another portion of the molecule (that is, any two indicated substituents may together form an alicyclic radical) and the like as well as two or more fused benzene nuclei. Such radicals are known to those skilled in the art, representative examples of which include methyl, ethyl, propyl, butyl, octyl, decyl, dodecyl, cyclohexyl, phenyl, tolyl, benzyl, naphthyl, anthryl, phenanthryl and the like.
The succinic acylating agents useful in preparing the additive compositions of this invention are aliphatic hydrocarbon based substituted succinic acids and anhydrides thereof having the following structural formulae Acid Anhydride
where R is hydrogen or an aliphatic hydrocarbon based radical containing 8 to 15 carbon atoms and most preferably from 9 to 15. carbon atoms. Although the source of the aliphatic hydrocarbon based substituent is not a critical aspect of the invention, this substituent will generally be a 1-mono-olefin or oligomers, prepolymers or low molecular weight polymers thereof. Representative examples of such 1-monoolefins include ethylene, propylene, 1-butene, isobutene, 1-hexene, 1-octene, 2-methyl-1-heptene, 3-cyclohexyl-1-butene, 2-methyl-5-propyl-1-hexene and the like. Medial monoolefins, i.e., olefins in which the olefinic linkage is not at the terminal position, and oligomers, prepolymers and low molecular weight polymers and low molecular weight polymers thereof are also useful. An illustrative example of such medial olefins is 4-octene.
The aliphatic hydrocarbon based substituted succinic acylating agents are well-known and can be prepared by various known procedures. One particularly useful procedure is to react a mono- olefin monomer or oligomer, prepolymer or low molecular weight polymer thereof as described above with maleic anhydride at 100°C to 200°C with or without a catalyst to form the corresponding substituted succinic anhydride. The monoolefin also can be replaced by an alkyl halide which is capable of being substituted onto the unsaturated anhydride or the equivalent free acid thereof.
The aliphatic hydrocarbon based substituent can be saturated or unsaturated, straight-chain or branched-chain and may contain polar groups provided, however, that such groups are not present in significantly large proportions as to alter the hydrocarbon character of the substituent. Polar groups are typified by halo, carbonyl, nitro and similar groups. In a preferred embodiment, the aliphatic hydrocarbon based substituent is a polyisopropenyl radical containing 12 carbon atoms.
The amines which are useful in preparing the additive compositions are monoamines which have the formula
wherein R, is an unsubstituted hydrocarbon based radical and R₂ and R₃ are independently hydrogen or unsubstituted hydrocarbon based radicals with the proviso that when R₂ and R₃ are both hydrogen, R, is a hydrocarbon based radical selected from the group consisting of tertiary alkyl, cycloalkyl, aryl, alkaryl and aralkyl radicals. In the inventions broader scope, the monoamines of the formula above can be straight-chain or branched-chain aliphatic, alicyclic and aromatic amines; monoamines wherein each of R_i, R₂ and R₃ are dissimilar such as aliphatic-alicyclic, aliphatic-aromatic and alicyclic-aromatic amines and substituted amines such as aliphatic substituted alicyclic, aliphatic substituted aromatic, alicyclic substituted aliphatic, alicyclic substituted aromatic, aromatic substituted aliphatic and aromatic substituted alicyclic amines. Preferably, the monoamines for use in preparing the compositions of the invention are those amines defined by the above formula wherein R,. is a hydrocarbon based radical containing from 1 to 24 carbon atoms selected from the group consisting of straight-chain and branched- chained alkyl radicals containing from 1 to 24 carbon atoms, cycloalkyl radicals containing from 5 to 7 carbon atoms, aryl radicals containing from 6 to 14 carbon atoms and alkaryl and aralkyl radicals containing from 7 to 20 carbon atoms and R₂ and R₃ are hydrogen or hydrocarbon based radicals selected from the group consisting of straight-chain or branched alkyl radicals containing from 1 to 24 carbon atoms, cycloalkyl radicals containing from 5 to 7 carbon atoms, aryl radicals containing from 6 to 14 carbon atoms and alkaryl and aralkyl radicals containing from 7 to 20 carbon atoms. When R₂ and R₃ are both hydrogen, thereby making the amine defined above a primary amine, then R, is a hydrocarbon based radical selected from the group consisting of tertiary alkyl radicals containing from about 5 to about 7 carbon atoms, cycloalkyl radicals containing from 4to about 24 carbon atoms, aryl radicals containing from about 6 to about 14 carbon atoms and alkaryl and aralkyl radicals containing from about 5 to about 7 carbon atoms. The purpose of the proviso described above is to ensure that R, will possess sufficient inherent stearic hindrance to inhibit any imide formation, the additives being primarily amidic acid salts or mixtures of amidic acid and amidic acid salts depending on the nature of the starting reactants and the relative ratios employed thereof. The amines will be free of any acetylenic unsaturation in the event any of the R groups of the amine should be unsaturated.
Representative, but nonlimiting examples of monoamines useful in the preparation of the compositions of this invention include dimethylamine, triethylamine, diethylamine, triethylamine, dipropylamine, tripropylamine, diisopropylamine, dibutylamine, tributylamine, diisobutylamine, triisobutylamine, tertiary butylamine, ethyl-n-butylamine, dimethyl butylamine, di-n-amylamine, tri-n-amylamine, dihexylamine, trihexylamine, dioctylamine, trioctylamine, N-dodecyl-1-dodecanamine, N-octadecyl-1-octa- decanamine, N,N-dimethyi-1-octadecanamine, cyclopentylamine, cyclopentenylamine, cyclohexylamine, dicyclohexylamine, methyl ethanolamine, benzylamine, aniline, o-phenylaniline, diphenylamine, 2-methyldiphenylamine, 3-methyldiphenylamine, 4,4'-dimethyldiphenylamine, 2,2'-diethyldiphenylamine, 4,4'-dioctyldiphenylamine, N - phenyl - 1 - naphthylamine, N - phenyl - 2 - naphthylamine and the like.
In one embodiment, the additive compositions are prepared by the reaction of the succinic acylating agent with secondary amines, or mixtures of secondary and tertiary amines in the manner described hereinbelow. In a preferred embodiment the additive compositions are prepared by the reaction of the succinic acylating agent with secondary amines. A most preferred secondary amine for use in preparing the additive compositions is dicyclohexylamine.
The corrosion inhibiting additive compositions may be readily prepared by heating mixtures of the aliphatic hydrocarbon based substituted succinic acylating agent with the amine at elevated temperatures ranging from about 30°C to about 200°C. A more preferred range of temperature is from about 50°C to about 150°C. Generally, however, very reasonable rates of reaction can be achieved from about 50°C to about 120°C.
The proportions of the reactants can vary widely. For example, the molar ratios of the aliphatic hydrocarbon-based substituted succinic acylating agent to the monoamine can range from about 1.0/0.5 to about 1.0/3.0. However, the preferred molar ratios range from about 1.0/1.0 to about 1.0/2.0 with the most preferred molar ratio being 1.0/2.0.'
The preparation of the additive compositions herein described can be carried out either in the absence or presence of a solvent. Preferably the compositions are prepared in the presence of solvent. Useful solvents can be hydrocarbon or polar solvents including, for example benzene naphtha, toluene, xylene, n-hexane, dioxane, chlorobenzene, kerosene, gasoline or a fuel oil or oil of lubricating viscosity.
The following examples illustrate the preparation of the additive compositions and the improved corrosion inhibiting characteristics of alcohol or alcohol containing normally liquid fuels containing these compositions, which fuels are in accordance with the invention. In the following examples all parts are by weight unless otherwise specified.

Example 1

Three hundred sixty-seven parts of tetrapropenyl-substituted succinic anhydride (prepared by reacting maleic anhydride with a polypropylene tetramer and having an average M.W. of about 248) is charged to a reaction vessel equipped with a stirrer, thermometer, reflux condenser and additional funnel. Starting at room temperature, 500 parts dicyclohexylamine is added over a period of 0.5 hour. The temperature of the reaction mixture rises to 45°C during the addition. The reaction is continued for 4.5 hours at 45°C. The temperature is increased to 60°C over 0.5 hour. The reaction product is then filtered and collected.

Example 2

Two hundred sixty-five parts of tetrapropenyl-substituted succinic anhydride, as described in Example 1, is charged to a reaction vessel equipped with a stirrer, thermometer, reflux condenser and additional funnel. Three hundred sixty-two parts of dicyclohexylamine is then added to the reaction vessel over a period of 2 hours while heating the reaction mixture to 120°C. The addition of the amine to the succinic anhydride is exothermic. The reaction is continued for 3 hours at 120°C. Three hundred twenty-two parts kerosene is then added to the reaction mixture. The materials are mixed thoroughly, filtered and collected.

Example 3

Two hundred sixty-six parts of tetrapropenyl-substituted succinic anhydride, as described in Example 1, and 338 parts of xylene are charged to a reaction vessel as described in the previous examples. The mixture is heated to 110°C with stirring, followed by the addition of 362 parts dicyclohexylamine over a period of one hour at 110―120°C. The reaction is continued for 3.25 hours at 110°C. The reaction mixture is then filtered and collected.

Example 4

,Two hundred forty-eight parts of an oil solution of tetrapropenyl-substituted . succinic acid (prepared by reacting tetrapropenyl-substituted succinic anhydride with water) are charged to a reaction vessel equipped as described in Example 1. Two hundred parts of dicyclohexylamine are then added over a period of 0.5 hour. The temperature of the reaction mixture rises from room temperature to 49°C during the amine addition. One hundred sixteen parts of mineral oil are then added and the mixture stirred for. an additional 0.5 hour. The materials are then filtered and collected.

Example 5

Two hundred sixty-six parts of tetrapropenyl-substituted succinic anhydride is charged to a reaction vessel as described in Example 1. The anhydride is heated to 100°C, followed by the addition of 20 parts of distilled water. The materials are reacted for 1.75 hours at 100°C. The reaction product (i.e., tetrapropenyl-substituted succinic acid) is then cooled to 55°C, at which time 362 parts dicyclohexylamine are then added to the acid. The addition of the amine is exothermic and the temperature of the reaction mixture increases to about 65°C. The reaction mixture is then heated to 70°C and reacted at this temperature for 4 hours. After cooling, 349 parts x_ylene are added. The xylene solution of reaction product is stirred thoroughly, filtered and collected.

Example 6

A reaction vessel equipped in the manner as described in Example 1 is charged with 98 parts of tetrapropenyl-substituted succinic anhydride (average M.W. 268) and 60 parts xylene. A solution consisting of 134 parts dicyclohexylamine and 65 parts xylene is then added over 0.5 hour. With addition of the amine solution the temperature of the reaction mixture increases from room temperature to about 34°C. The reaction mixture is then heated to 75°C and reacted at that temperature for a total of 5 hours. The solution containing the reaction product is then cooled, filtered and collected.

Example 7

Two hundred sixty-six parts of tetrapropenyl-substituted succinic anhydride are charged to a reaction vessel equipped as described in Example 1. Then 374 parts Primene 81 R (a mixture of C₁₂-₁₄ t-alkyl primary amines available commercially from Rohm & Haas Co.) are added dropwise over 3 hours. The reaction is exothermic and the temperature of the reactant increases from room temperature to about 59°C over the course of the amine addition. One hundred sixty parts of diluent oil are then added to the reaction product and stirring is continued for an additional hour at 55°C. After cooling to 40°C the material is filtered and collected.

Example 8

Two hundred twenty-six parts of tetrapropenyl-substituted succinic anhydride is charged to a reaction vessel as described in Example 1. Then 362.6 parts of dicyclohexylamine is added dropwise to the reaction vessel over one hour. The reaction of the anhydride and amine is exothermic and the temperature of the reaction mixture increases to 36°C. The mixture is reacted at 36-45°C while heating for one hour. The product is then filtered and collected.

Example 9

To a solution of 266 parts tetrapropenyl-substituted succinic anhydride in 253 parts xylene contained in a reaction vessel as described in Example 1 is added a solution of 362.6 parts dicyclohexylamine in 85 parts xylene over a period of one hour. The temperature increases exothermically to 32°C during the addition. The materials are then reacted at 32-50°C for one hour, filtered and collected. Sixty parts of this product is then diluted further with 40 parts xylene and mixed thoroughly.

Example 10

A series of alcohol fuels are prepared by blending from 35 to 450 parts by weight of one of the reaction products of Examples 1 through 9 with hydrated ethanols containing about 7.5 percent by weight water.

Example 11

A series of alcohol containing gasoline fuels is prepared by blending from 35 to 450 parts by weight of one of the reaction products of Examples 1 through 9 with a gasohol which comprises 20 percent by volume of hydrated ethanol and 80 percent by volume of a gasoline having an ASTM distillation range of from about 60°C at the 10 percent distillation point to about 205°C at the 90 percent distillation point.
The corrosion inhibiting effectiveness of the additive compositions were tested in accordance with Method K, Test C of the Brazilian Association of Technical Norms (ABNT). In this test, various metal specimens (e.g. steel, brass and zinc/ aluminum alloy) are immersed in commercially available hydrated ethanol for a continuous period of 144 hours at a temperature of 50°C±3°C. At the end of the test period each test specimen is then rinsed first with water and then with a ketone or other suitable solvent and dried. After drying, each test specimen is weighed and its visual appearance noted. The weight loss, if any, and visual appearance of the specimens are then compared to those of specimens treated in the same manner in a control or reference gasoline/alcohol blend comprised of 78 to 82 percent by volume of gasoline and 22 to 18 percent by volume of 100 percent absolute ethanol. For a corrosion inhibiting additive composition to-be considered effective, neither the weight loss nor the visual appearance of specimens tested with additive containing hydrated ethanol can vary from those treated in the control or reference gasoline/alcohol blend by more than 10 percent. The corrosion inhibiting additive compositions described in Examples 1 through 9 above are found to be effective when tested in accordance with this Brazilian method. Fuel compositions in accordance with the invention for use in internal combustion engines may comprise, for example, (A) a major portion of a fuel containing (i) at least one alcohol having from 1 to five carbon atoms and (ii) a normally liquid hydrocarbonaceous petroleum distillate fuel and (B) a minor portion of a corrosion inhibiting reaction product as described hereinabove.
Alcohol fuels useful in combination with the corrosion inhibiting reaction products of succinic acylating agents and amines as described herein to provide fuel compositions having improved corrosion inhibiting characteristics include such commercially available alcohols as methanol, ethanol, propanol, isopropanol, butanol and its isomers and amyl alcohol and its isomers and mixtures of these various alcohols. As produced commercially the preferred alcohols are methanol and ethanol.
The normally liquid hydrocarbonaceous petroleum distillate fuels which are useful in combination with alcohols and the corrosion inhibiting reaction products described herein above include motor gasoline as defined by ASTM Specification D439 and diesel fuel or fuel oil as defined by ASTM Specification D396. A particularly preferred petroleum distillate fuel, howver, is gasoline, that is, a mixture of hydrocarbons having an ASTM distillation range of from about 60°C at the 10 percent distillation point to about 205°C at the 90 percent distillation point.
The fuel portion of the fuel compositions of this invention generally comprises from 2.00 to 100 percent by volume of at least one alcohol containing from 1 to 5 carbon atoms and from 98.0 to 0 percent by volume of the normally liquid hydrocarbonaceous petroleum distillate fuel. In a preferred embodiment, this fuel portion will comprise from 10.0 to 100 percent by volume of at least one alcohol containing from 1 to 5 carbon atoms and from 90.0 percent to 0 percent of the petroleum distillate fuel. In a more preferred embodiment, the ranges of the alcohol and petroleum distillate fuels employed in the fuel compositions of this invention will be from 20.0 to 100 percent by volume and from 80.0 to 0 percent by volume respectively. Particularly preferred fuel compositions are those based on a mixture of an alcohol, especially methanol or ethanol, and a petroleum distillate fuel, especially gasoline, in which mixture the alcohol component ranges from 10.0 to 20.0 percent by volume and the petroleum distillate fuel ranges from 90.0 to 80.0 percent by volume.
The amount of the additive reaction product of the succinic acylating agent and amine added to the above described fuel portion to provide the fuel compositions of the invention will be an. amount sufficient to impart improved corrosion inhibiting characteristics to these fuel compositions. Broadly this amount will range from about 10 to about 1000 parts by weight of said additive reaction product per million parts by weight of the fuel portion. Preferably this amount will range from about 10 to about 450 parts by weight with a range of from about 175 to about 450 parts by weight of said additive reaction product per million parts by weight of said fuel portion being most preferred.
The fuel compositions of this invention can be prepared by merely adding the reaction product of the succinic acylating agent and amine directly to the fuel portion or it can be diluted with a substantially inert, normally liquid organic diluent such as naphtha, benzene, toluene, xylene, or a petroleum distillate fuel as described above, to form a concentrate of said reaction product which is then added to the fuel portion. These concentrates generally contain from about 20 percent to about 90 percent of the additive reaction products of the invention.
The fuel compositions described hereinabove, may also contain additional materials normally added to liquid fuels to obtain specific benefits. Therefore, the fuel compositions may contain antiknock agents such as tetraalkyl lead compounds, lead scavengers such as haloalkanes (e.g., ethylene dichloride and ethylene dibromide) deposit preventers or modifiers such as triaryl phosphates, dyes, octane improvers, antioxidants such as 2,6-di-tertiary-butyl-4-methylphenol, bacteriostatic agents, gum inhibitors, metal deactivators, demulsifiers, upper cylinder lubricants and anti-icing agents.

Claims

1. A fuel composition comprising a major amount of an alcohol or alcohol containing normally liquid hydrocarbonaceous petroleum distillate fuel and a minor amount of a reaction product of (A) at least one substituted succinic acylating agent, the substituent on said substituted succinic acylating agent being an aliphatic hydrocarbon based group of 8-15 carbon atoms; with (B) at least one monoamine of the formula

wherein R, is an unsubstituted hydrocarbon based radical and R₂ and R₃ are independently hydrogen or unsubstituted hydrocarbon based radicals with the proviso that when R₂ and R₃ are both hydrogen, R, is a radical selected from tertiary alkyl, cycloalkyl, aryl, aralkyl and alkaryl radicals.

2. A composition of Claim 1 wherein the substituent on the acylating agent (A) is alkyl or alkenyl.

3. A composition of either of Claims 1 and 2 wherein the substituent on the acylating agent (A) is straight-chained or branched chain.

4. A composition of any one of the preceding claims wherein the substituent on the acylating agent (A) has 9 to 15 carbon atoms.

5. A composition of Claim 4 wherein the substituent on the acylating agent (A) has about 12 carbon atoms.

6. A composition of any one of the preceding claims wherein R, has 1 to 24 carbon atoms.

7. A composition of any one of the preceding claims wherein R₂ and R₃ are independently hydrogen or hydrocarbon based groups of 1 to 24 carbon atoms.

8. A composition of any one of the preceding claims wherein R, is a hydrocarbon-based radical selected from tertiary alkyl radicals containing 4 to 24 carbon atoms, cycloalkyl radicals containing 5 to 7 carbon atoms, aryl ·radicals containing 6 to 14 carbon atoms and alkaryl and aralkyl radicals containing 7 to 20 carbon atoms.

9. A composition of any one of the preceding claims wherein R, is selected from straight-chain or branched-chain alkyl or alkenyl radicals containing 1 to 24 carbon atoms, cycloalkyl radicals having 5 to 7 carbon atoms, aryl radicals having 6 to 14 carbon atoms, and alkaryl and aralkyl radicals containing 7 to 20 carbon atoms; and R₂ and R₃ are independently hydrogen or hydrocarbon based radicals selected from straight-chain or branched-chain alkyl or alkenyl radicals having 1 to 24 carbon atoms, cycloalkyl radicals having 5 to 7 carbon atoms, aryl radicals containing 6-14 carbon atoms and alkaryl and aralkyl radicals containing 7 to 20 carbon atoms.

10. A composition of any one of the preceding claims wherein said alcohol or alcohol-containing liquid fuel comprises (i) 2 to 100 percent by volume of at least one alcohol having 1 to 5 carbon atoms, and (ii) 98 to 0 percent by volume of a normally liquid hydrocarbonaceous petroleum distillate fuel.

11. A composition of Claim 10 wherein said liquid fuel comprises (i) 10 to 100 percent by volume of at least one alcohol having 1 to 5 carbon atoms, and (ii) 90 to 0 percent by volume of a normally liquid hydrocarbonaceous petroleum distillate fuel.

12. A composition of Claim 11 wherein said liquid fuel comprises (i) 20 to 100 percent by volume of at least one alcohol having 1 to 5 carbon atoms, and (ii) to 80 to 0 percent by weight of a normally liquid hydrocarbonaceous petroleum distillate fuel.

13. A composition of any one of the preceding claims wherein the alcohol is methanol, ethanol or a mixture thereof.