US3033665A - Nonstalling gasoline motor fuel - Google Patents

Description

United States Patent Office 3,033,665 Patented May 8, 1962' Delaware No Drawing. Filed Aug. 1, 1958, Ser. No. 752,411 9 Claims. (Cl. 4466) This invention relates to gasoline fuel compositions, and more particularly to gasoline fuel compositions that have reduced engine stalling tendencies at cool, humid atmospheric conditions.

When an internal combustion engine is operated at cool, humid atmospheric conditions, using a gasoline fuel having a relatively low 50 percent ASTM distillation point, i.e., below about 235 F., excessive engine stalling is apt to be encountered at idling speeds during the Warm-up period, especially where engine idling occurs following a period of light load operation. Engine stalling under such conditions has been attributed to the partial or complete blocking of the narrow air passage that exists between the carburetor throat and the carburetor throttle valve during engine idling, by ice particles and/or solid hydrocarbon hydrates that deposit upon and adhere to the metal surfaces of the carburetor parts. :Such icing of carburetor parts occurs as a result of the condensation of moisture from the air drawn into the carburetor and as a result of the solidification of such condensed moisture. The aforesaid condensation and solidification of moisture are caused by the refrigerating effect of rapidly evaporating gasoline. Accordingly, excessive engine stalling due to carburetor icing occurs as a practical matter only in the instance of gasolines containing a large proportion of relatively highly volatile components. In practice, the problem of engine stalling due to carburetor icing has been found to be serious, under cool, humid atmospheric conditions, in connection with gasolines having a 50 percent ASTM distillation point below about 220 F.

Excessive engine stalling is, of course, a source of annoyance owing to the resulting increased fuel consumption, battery wear and inconvenience of frequent restarting. It is therefore important that the inherent engine stalling characteristics of gasoline fuels be reduced substantially where the 50 percent ASTM distillation point of such gasoline fuels is sufficiently low to cause a problem in this respect.

The present invention relates to gasoline fuel compositions that comprise hydrocarbon mixtures boiling in the gasoline range and that normally tend to promote engine stalling by carburetor icing, which fuel compositions exhibit reduced engine stalling tendencies, and which are thereby rendered more suitable for use as motor fuels. We have found that such improved gasoline compositions can be obtained by incorporating therein a small amount of a quaternary ammonium salt wherein two of the covalent N-bonds are attached to aliphatic hydrocarbon substituents containing 8 to 22 carbon atoms and the remaining covalent N-bonds are attached to saturated aliphatic hydrocarbon radicals containing 1 to 4 carbon atoms, and wherein the ionic N-bond is attached to an anionic salt-forming radical derived from a member selected from the group consisting of (a) oil-soluble organic I mono-carboxylic acids containing 7 to 30 carbon atoms per molecule, (b) oil-soluble monohydric phenols having attached to the aromatic nucleus 1 to 3 hydrocarbon substituents containing at least four carbon atoms, and having not more than one substituent in the ortho position that contains more than one carbon atom, (c) oil-solube monoand di-acid esters of o-phosphori'c acid having as one phosphato substituent an aliphatic hydrocarbon radical containing 8 to 22 carbon atoms, and as another a member selected from the class consisting of hydrogen and aliphatic hydrocarbon radicals containing 2 to 22 carbon atoms, and (d) oil-soluble hydrocarbon sulfonic acids. Especially good results are obtained from di-C alkyl, di-C alkylammonium dialkyl o-pho'sphates and alkyl phenates, such as dioctadecyldimethylammonium di Oxo octyl o-phosphate, bis(dioctadecyldimethylammonium isooctyl o-phosphate, dioctadecyldimethylammonium p-tert-octyl phenate. However, good results are also obtained with other quaternary ammonium salts of the class disclosed, for example, dioctyldecyldimethylammonium naphthenate, dioctadecyldimethylammonium oil-soluble petroleum sulfonate, and others. The invention is important in connection with gasolines having a 50 percent ASTM distillation point not greater than about 220 F., as such gasolines normally involve a severe engine stalling problem due to carburetor icing.

I The quaternary ammonium salts Whose use is included by this invention are polar, surface active materials. While the invention is not limited to any theory of operation, it might appear that the addition agents disclosed herein, by virtue of their polarity, tend to orient themselves upon the metal surfaces of the throttle valve and other critical carburetor parts contacted by the gasoline compositions, thus forming a moisture displacing residual coating upon said carburetor parts which tends to prevent theadherence to said metal surfaces of accumulations of ice of such magnitude as to block the narrow air passages that exist in a carburetor throat at engine idling conditions. It is also considered possible that the addition agents disclosed herein may tend to orient themselves about small, ice particles, thus tending to prevent the formation of macrocrystals of ice of a size suflicient to block carburetor air passages at engine idling conditions. Although the elfectiveness of the herein disclosed addition agents is believed to be attributable in some way to the particular polar, surface active characteristics thereof, this general explanation is more or less negatived by the fact that many other surface active agents, including for example, other quaternary ammonium salts, have little or no effect upon the carburetor icing tendencies of gasolines.

The quaternary ammonium salts disclosed herein can be prepared in any suitable manner. Inasmuch as'the method of preparing the quaternary ammonium salts disclosed herein does not as such constitute any part of this invention, such preparation need not be described in detail. However, in the interest of clarity it may be mentioned that according to a preferred procedure the quaternary ammonium salts disclosed herein are formed by neutralizing an appropriate quaternary ammonium hydroxide with an oil-soluble acid of the kind disclosed herein. This reaction proceeds spontaneously at ambient atmospheric conditions with evolution of heat. The quaternary ammonium hydroxide is conveniently prepared by reacting a suitable quaternary ammonium halide with an alkali metal hydroxide, e.g., potassium hydroxide'in an alcoholic solution, thus forming a precipitate of an alkali metal halide and an alcoholic solution of a quaternary ammonium hydroxide. Several quaternary ammonium halides suitable for use in preparing the quaternary ammonium salts disclosed herein can be obtained commercially. When this is not the case, the desired quaternary ammonium halide can be prepared in conventional fashion, i.e., by reacting an appropriate tertiary amine with an appropriate alkyl halide. The detailed preparations of several quaternary ammonium salts of the kind disclosed 3 herein are described in the present assignees copending application Ser. No. 538,799, filed in the name of Earl E. Myers, on October 5, 1955.

Any quaternary ammonium hydroxide having two of its covalent N-bonds attached to aliphatic hydrocarbon substituents containing 8 to 22 carbon atoms and the remaining covalent N-bonds attached to aliphatic hydrocarbon atoms containing 1 to 4 carbon atoms can be utilized to form quaternary ammonium salts useful for the purposes of this invention. It is important that two of the covalent N-bonds be attached to long-chain aliphatic hydrocarbon substituents as the presence of two such substituents imparts especially desirable gasoline solubility and water insolubility characteristics to the quaternary ammonium salts. Such characteristics are important to avoid any reduction in antistalling properties on account of a reduction in the effective concentration of the addition agent due to separation from solution or water leaching. The long-chain aliphatic hydrocarbon radicals can be, for example, alkyl, alkenyl or alkadienyl radicals containing 8 to 22 carbon atoms. Quaternary ammonium hydroxides wherein the two long-chain aliphatic hydrocarbon substituents are alkyl groups containing 12 to 18 carbon atoms form especially effective quaternary ammonium salts for the purposes of this invention. The two long-chain aliphatic hydrocarbon N-substituents can be derived from natural fats and oils, for example, coconut oil, soybean oil, animal tallow and the like. In such instances the long-chain aliphatic hydrocarbon radicals will consist essentially of mixed alkyl and alkenyl groups containing 8 to 22 carbon atoms. The two short-chain aliphatic hydrocarbon N-substituents can be any lower alkyl group, although methyl and ethyl substituents are preferred for the reason that they tend to minimize hindrance to addition of the long-chain substituents to the nitrogen atom. These substituents can comprise, for example, isopropyl, propyl, or butyl radicals. Examples of preferred quaternary ammonium hydroxides are didodecyldimethylammonium hydroxide, ditetradecyldimethylammonium hydroxide, dihexadecyldimethylammonium hydroxide, and dioctadecyldimethylammonium hydroxide. Examples of other quaternary ammonium hydroxides that can be used are dioctyldiethylammonium hydroxide, didodecenyldibutylammonium hydroxide, dioctadecenyldimethylammonium hydroxide and dioctadecadienyldiethylammonium hydroxide.

The nature of the acidic component of the quaternary ammonium salts disclosed herein is of great importance to the present invention, inasmuch as the acidic components contribute significantly to the antistalling properties of the quaternary ammonium salts. Nevertheless, various oil-soluble acids of the class disclosed above can be used to form quaternary ammonium salts that are useful for the purposes of this invention. Oil-soluble organic monocarboxylic acids that can be used to form salts of this invention will normally contain 7 to 30 carbon atoms. Quaternary ammonium salts wherein the anionic substituent is a salt-forming radical derived from petroleum naphthenic acids constitute a preferred class of carboxylic acid salts. As is known, such naphthenic acids are mixed alicyclic monocarboxylic acids recovered by alkali washing of petroleum such as kerosene, naphtha, gas, oil, and lubricating distillates. The acids derived from these distillates are mixtures of alicyclic monocarboxylic acids containing about 7. to 30 carbon atoms per molecule, which mixtures have average molecular weights in the range of about 200 to 450. Within the general class of petroleum naphthenic acids, the higher molecular weight acids derived from higher boiling distillates and containing 14 to 30 carbon atoms per molecule and having molecular weights of about 250 to 450 are considered to form especially effective quaternary ammonium salts for the purposes of this invention. Examples of other monocarboxylic acids that can be used to form quaternary ammonium salts whose use is included by this invention are: oil-soluble synthetic naphthenic acids such as cyclo- .hexylacetic, cyclohexylpropionic, and cyclohexylstearic acids, and oil-soluble saturated or unsaturated fatty acids, such as caprylic, lauric, myristic, palmitic, stearic, oleic, and linoleic acids. Mixtures of long-chain fatty acids such as those derived from the saponification of natural fats and oils also can be used to form quaternary ammonium salts within the scope of this invention. Examples of such mixed fatty acids are coconut, soya, and tallow fatty acids. In such instances the acids will consist essentially of mixtures of oil-soluble, straight-chain, unsubstituted monocarboxylic acids containing 8 to 22 carbon atoms.

As previously indicated, phenols that form salts whose use is included by this invention are oil-soluble monohydric phenols having attached to the aromatic nucleus at least one hydrocarbon substituent containing at least four carbon atoms and having not more than one substituent in the ortho position that contains more than one carbon atom. Although mono-substituted phenols are preferred, phenols containing 2 or 3 nuclear hydrocarbon substituents can be used. The hydrocarbon substituent or substituents can be straight or branched chain and saturated or unsaturated. The hydrocarbon substituent or substituents and even the aromatic nucleus itself may contain substituents containing halogen, oxygen, phosphorous, nitrogen or sulfur, e.g., chloro, nitro, amino, aryl, keto, or mercapto groups which do not affect the oil-solubility of the phenol and which do not react preferentially with the quaternary ammonium hydroxide. Phenols of the preferred class possess particularly advantageous solubilizing and salt-forming characteristics.

Oil-soluble, monohydric phenols containing one aliphatic hydrocarbon substituent, having 4 to 15 carbon atoms, in the meta or para position to the hydroxyl group are considered to form especially effective quaternary ammonium salts Within the scope of this invention. For example, outstanding results have been obtained with quaternary ammonium salts of p-tert-octylphenol. EX- amples of other phenols that form suitable quaternary ammonium salts are p-tert-butylphenol, p-tert-amylphenol, p-sec-amylphenol, o-sec-arnylphenol, o-tert-amylphenol, p-nonylphenol, cardanol, which consists essentially (approx. of a mixture of C straight chain meta-substituted phenols with different degrees of unsaturation in the side chains, hydrocarbanol, i.e., m-pentadecylphenol, 2,6 dimethyl 4 tert butylphenol, 2 tert amyl 4-methylphenol, 3-methyl-6-tert-butylphenol, 2-methyl- 4,6-di-tert-butylphenol, and 2,4-di-tert-butylphenol.

As suggested above, oil-soluble acid esters of o-phosphoric acid that form salts whose use is included by this invention are those having the general formula:

r ITO-1 :0 (gRII wherein R is an aliphatic hydrocarbon radical containing 8 to 22 carbon atoms and R" is a member selected from the class consisting of hydrogen and aliphatic hydrocarbon radicals containing 2 to 22 carbon atoms. Acid esters of o-phosphoric acid that form a preferred class of quaternary ammonium salts according to this invention are those wherein R is an aliphatic hydrocarbon radical containing 8 to 18, and preferably'8 to 12 carbon atoms and wherein R" is an aliphatic hydrocarbon radical containing 2 to 8 carbon atoms. Specific A, i l e,

examples of acid esters of o-phosp'horic acid capable of jk forming preferred quaternary ammonium salts according to this invention are diisooctyl acid o-phosphate, isoamyl octyl acid o-phosphate, ethyl lauryl acid o-phosphate, and ethyl oleyl acid o-phosphate. =Other acid esters of o-pbosphoric acid that form quaternary ammonium salts suitable for the purposes of this invention are dilauryl acid o-phosphate, dioleyl acid o-phosphate, dimyristyl acid o-phosphate, dipalmityl acid o-phosphate, octyl di-acid o-phosphate, lauryl di-acid o-phosphate, and oleyl di-acid o-phosphate.

The sulfonic acids that form quaternary ammonium salts whose use in included by this invention are the oilsoluble hydrocarbon sulfonic acids. Such acids may be represented by the generic formula RSO H, where R is an organic radical of at least predominantly hydrocarbon character that is capable of imparting oil-solubility to the acid. These sulfonic acids may be oil-soluble aliphatic hydrocarbon sulfonic acids, including naphthenic hydrocarbon sulfonic acids, representative examples of the former of which are octyl, nonyl, decyl, undecyl, lauryl, tridecyl and myristyl sulfonic acids, and of the latter, the octyl-, dodecyl-, and dodecenyl-cyclopentyl and similarly substituted cyclohexyl sulfonic acids. Also satisfactory are the alkaryl sulfonic acids such as octyl, decyl, dodecyl and cetyl benzenesulfonic acids, as well as the socalled keryl, or kerosene, and wax-alkyl benzenesulfonic acids, including the corresponding dialkyl benzenesulfonic acids. The preferentially oil-soluble petroleum sulfonic acids, normally referred to as mahogany acids, in order to differentiate them from the preferentially water-soluble green acids, are especially suitable for the purposes of this invention. As is well known in the art, oil-soluble petroleum sulfonic acids can be derived by sulfonation of higher boiling petroleum fractions, normally those having lubricating properties, with conventional sulfonating agents such as oleum, sulfur trioxide, or the like. able from the thus-treated oils by neutralization With aqueous alkali, such as aqueous caustic soda solution, extraction with alcohol or aqueous alcohol, distillation to remove the extraction solvent, and regeneration of the sulfonic acid by treatment of the residue with an equivalent amount of a mineral acid. Particularly suitable mahogany acids are those having an average molecular Weight between about 400 and about 650.

The antistalling addition agents disclosed herein are useful when incorporated in gasoline compositions of the type disclosed in any amount sufficient to reduce the engine stalling characteristics thereof. For example, an improvement in the stalling characteristics of gasolines of the type disclosed herein will normally be obtained by addition thereto of the herein disclosed addition agents in amounts of at least 0.001 percent by weight of the composition (approx. 2.5 to 2.6 lbs./ 1000 bbls. gasoline). Preferably the anti-stalling addition agents disclosed here in will be employed in proportions of at least 0.006 percent by weight of the composition (approx. lbs./ 1000 bbls. gasoline). Thus, a marked improvement in the stalling characteristics of gasolines has been obtained by incorporation therein of addition agents of the kind disclosed herein in proportions of about 15 to 25 pounds per thousand barrels of gasoline. Accordingly, We normally prefer to employ the addition agents disclosed herein in proportions of about 15 to 50 pounds per thousand barrels of gasoline. Although in some instances it may be desired to employ the antistalling addition agents disclosed herein in amounts in excess of 250 pounds per thousand barrels of gasoline, that is, 0.1 percent by weight or more, such proportions are usually not necessary and normally produce no significant additional improvement in the stalling characteristics of the gasoline. In no instance should the antistalling addition agents disclosed herein be added to gasoline in amounts such as to produce a significant adverse effect on the volatility, combustibility, antiknock or gum-forming char- I l acteristics of the gasoline.

It will be appreciated that the optimum proportion of the antistalling addition agents disclosed herein can vary within the range indicated above in accordance with the particular gasoline employed, inasmuch as the problem of engine stalling due to carburetor icing is a function of the 50 percent ASTM distillation point of the gaso- The oil-soluble sulfonic acids are recover- 6 line. Thus, greater concentrations of the antistalling addition agents are normally desirable with decreasing 50 percent ASTM distillation points. The optimum concentration of the antistalling addition agents disclosed herein may also vary somewhat in accordance with the particular make and model of engine in which the gasoline is used, as well as in accordance with the severity of the atmospheric conditions encountered. With regard to this last-mentioned factor, the problem of engine stalling due to carburetor icing resulting from the refrigerating effect of evaporating gasoline upon moisture condensed from the atmosphere has been found to be serious at low temperatures, e.g., 35, 40, 45, 50, and when the relative humidity is in excess of about 55 percent, e.g., 75 percent, and 99 percent. The optimum proportion of the antistalling addition agents disclosed herein, in any given case, will be sufficient to effect substantial reduction in the stalling tendencies of the fuel at the particular atmospheric conditions of temperature and humidity which are likely to be encountered in service.

Practically speaking, the problem of engine stalling due to carburetor icing caused by rapid evaporation of gasoline occurs only in connection with gasolines having a 50 percent ASTM distillation point less than 235 F. While occasional engine stalling may occur as a result of carburetor icing at severe atmospheric conditions of temperature and humidity with gasolines having somewhat higher 50 percent ASTM distillation points, experience has indicated that the problem does not assume major importance except with gasolines of the character indicated. As indicated, the problem of engine stalling due to carburetor icing is especially severe in connection with gasolines having a 50 percent ASTM distillation point of less than about 220 F. The invention is important in connection with such gasolines. The term gasoline is used herein in its conventional sense to include hydrocarbon mixtures having a percent ASTM distillation point of not more than about 392 F. and a 10 percent ASTM distillation point of not greater than 149 F. However, it is obvious that some deviation from these limits can be tolerated without substantially changing the essential characteristics of a gasoline. Accordingly, the invention includes the use of borderline gasolines of this kind.

The antistalling addition agents whose use is included by this invention can be incorporated in the base gaso line fuel compositions in any suitable manner. Thus, they can be added as such to gasoline or in the form of dispersions or solutions in solvents such as butanol, isopropanol, ethanol, methanol, benzene, toluene, heptane, kerosene, gasoline, mineral lubricating oil, or the like, which solvents may be or may not themselves contribute to the antistalling characteristics of the gasoline motor fuel composition. If desired, the herein disclosed antistalling addition agents can be incorporated in gasoline fuel compositions in admixture with other materials designed to improve one or more properties of the gasoline, such as antioxidants, anti-gumming agents, e.g., 2,6- ditertiarybutyl, 4-methylphenol, antiknock agents, e.g., tetraethyl lead, lead scavenging agents, e.g., ethylene dibromide, ethylene dichloride, corrosion inhibitors, e.g., oil-soluble dialkyl amine phosphates, dyes, and the like.

The utility of the gasoline motor fuel compositions of this invention has been demonstrated by two diiferent test procedures. In one test, referred to hereinafter as the Mock Fuel System Test, test fuel is supplied at about 50 F. together with air at about 60 F. and about 75 percent relative humidity at controlled rates to the glass vaporizer chamber held at an absolute pressure of 12 inches of mercury (temperature initially at 50 F.), and by observing the time for icing to occur on a movable brass throttle plate positioned in the vaporizer chamber. Performance of a test fuel is determined by comparing the time for icing formation on the brass throttle plate with that required for the uninhibited fuel under the same test conditions. In these tests the base gasoline employed,

7 hereinafter referred to as Test Fuel A, had the following characteristics.

isooctyl o-phosphoric acids, hereinafter referred to as Compound 3. Bis(dioctadecyldimethylammonium) iso- Ins ectiorw octyl o-phosphate and dioetadecyldimethylammonium dip g, API 62 6 isooctyl o-phosphate were the predominant components Knock Rating of Compound 3. The mixed acid esters of o-ph ph ric Motor m'ethod octane No 842 acid employed in preparing Compound 3 comprised a Research method octane I mixture of diisooctyl acid 0-ph0sphate and i YI TEL ml /ga1 u 3 acid o-phosphate in approximately 1:1 mol proportion vapljr g'fi 'ig 4 This mixture of acids had an average molecular W igh Distillation gagolinez 10 of about 266, a phosphorus content calculated as P2 5 of Over imint e F 100 27.0 percent, a specific gravity at 25 C./4 C- Of 1.020, End point e 394 a refractive index at 25 C. of 1.4428. Another quater- 10% evapgrated at o F 135 nary ammonium salt tested was the di(hydrogenated al- 50% evaporated at o F 210 low alkyl)dimethylarnmoniurn salt of oil-soluble petro- 90% fivaporated at F 316 leurn sulfonic acids, hereinafter referred to as Compound 4. An oil solution of the oil-soluble petroleum sulfonic According to the other test procedure employed, hereacids employed in the separation of Compound 4 had an inafter referred to as the Cold Room Engine Test, a 216 ash content of 0.25 percent and a neutralization number cu. in. Chevrolet engine employing a standard Carter of 35.2. The petroleum sulfonic acids component of the down-draft carburetor, is Operated at no load 0 a st solution had a calculated average molecular Weight of stand under cycling conditions in a cold room maintained about 460. at -F. for a warm-up period of 20 cycles. Each cycle The results of the above-described tests are set forth comprises 40 seconds at 2000 rpm. followed by an idle in the following table:

Table A Test Test Example Fuel 1 2 Fuel 3 4 5 6 A B Make-Up, Percent by Vol.2

Test Fuel A To B Added Lb./l 000 Bbls Compound Compound2 Compound 3 Compound 4 Inspections:

Mock Fuel System Test Time to Icing, Min Cold Room Engine Test Stalls Encountered During Warm-Up, No

for 20 seconds at 450 r.p.rn. Air is supplied to the carburetor at ambient conditions and at approximately 85 percent relative humidity. The number of engine stalls is observed and reported as stalls per 20 cycles. The base gasoline employed in connection with this test procedure, hereinafter referred to as Test Fuel B, had the following characteristics.

One of the compounds employed in the abovedescribed tests Was di(hydrogenated tallow alkyl)dimethylammonium naphthenate, hereinafter referred to as Compound 1. This salt was prepared from petroleum naphthenic acids boiling in the range 145 to 185 C. at 3 mm. Hg, having a neutralization value of 213 and an average molecular Weight of about 38 The hydrogenated tallow alkyl radical consists essentially of a mixture of (1 E1 and C13H37 radicals, with the latter predominating. Another salt employed in the tests was di(hydrogenated tallow aIkyDdimethylammonium p-tert-octyl phenate, hereinafter referred to as Compound 2. Another material tested was a mixture of neutral di(hydrogenated tallow alkyl) dirnethylammonium salts of a mixture of isooctyl and di- From the experimental results presented in the foregoing table it will be seen that the quaternary ammonium salts of the class disclosed herein are effective in reducing the carburetor icing tendencies of gasolines that normally tend to promote carburetor icing. The results obtained indicate that Compounds 2 and 3 are especially effective gasoline antistalling agents.

It will be understood that the invention is not limited to the specific compositions disclosed above and that good results can be obtained by the substitution of other normally stalling gasolines and by the substitution of other quaternary ammonium salts disclosed herein in the same or equivalent proportions for the corresponding components therein. "For example good results can be obtained by incorporating into Test Fuel A and Test Fuel B in the proportions of 25 pounds per thousand barrels of gasoline of the dioctyldimethylammonium, the didodecyldiethylammonium, the dihexadecyldipropylammonium, and the dioctadecenyldimethylammonium salts of petroleum naphthenic, oleic, stearic, caprylic, and cyclohexylstearic acids, p-tert-amylphenol, p-sec-amylphenol, o-sec-amylphenol, o-tert-amylphenol, p-nonylphenol, cardanol, m-pentadecylphenol, 2,6-dimethyl-4-tert-butylphenol, 2- tert-amyl-4-methyl-phenol, 3-methyl-6-tert-butylphenol Z-methyl-4,6-di-tert-butylphenol, 2,4-di-tert-butylphenol, diisooctyl o-phosphoric acid, is'ooctyl o-phosphoric acid, dilauryl o-phosphoric acid, dirnyristyl o-phosphoric acid, dioleyl o-phosphoric acid, octyl o-phosphoric acid and ethyl lauryl o-phosphoric acid.

It is emphasized that the remarkable properties of the addition agents disclosed herein are attributable both to the nature of the covalent N-substituents and of the ionic N-substituent. Indicative of the importance of the character of the covalent N-substituents of the quaternary ammonium salts Whose-use is included by this invention is the fact that benzyltrimethylammonium p-tert-octyl phenate and the tetramethyl ammonium salt of oil-soluble petroleum sulfonic acids were found to be substantially insoluble in benzene, even in low concentrations, thus in dicating the unsuitability of these materials as gasoline additives. Indicative of the importance of the character of the ionic N-substituent is the fact that dihydrogenated tallow dimethylammonium chloride, even in the proportion of 250 pounds per thousand barrels of gasoline, was found to extend the time for icing in the Mock Fuel System Test to only three minutes, an unsatisfactory performance according to the test.

To the gasoline fuel compositions of the present invention there can be added one or more additional agents designed to improve one or more characteristics of the gasoline fuel. For example, antioxidants, antiknock agents, ignition control additives, other de-icing agents, antirust agents, dyes, lead scavenging agents and the like can be added to the gasoline compositions of this invention and the invention specifically includes gasoline compositions containing such additives.

Numerous additional embodiments of the invention will readily suggest themselves to those skilled in the art. Accordingly, only such limitations should be imposed on the invention as are indicated in the claims appended hereto.

We claim:

1. A gasoline motor fuel composition comprising a major amount of a hydrocarbon mixture boiling in the gasoline range, that has a 50 percent ASTM distillation point not greater than 220 F. and that normally tends to promote stalling of internal combustion engines and a minor amount, sufficient to reduce the engine stalling characteristics of said composition of a quaternary ammonium salt wherein two of the co-valent N-bonds are attached to aliphatic hydrocarbon substituents containing 8 to 22 carbon atoms and the remaining co-valent N- bonds are attached to saturated aliphatic hydrocarbon radicals containing 1 to 4 carbon atoms, and wherein the ionic N-bond is attached to an anionic salt forming radical derived from a member selected from the group consisting of (a) oil-soluble organic monocarboxylic acids containing 7 to 30 carbon atoms per molecule, (b) oilsoluble monohydric phenols having attached to the aromatic nucleus one to three hydrocarbon substituents containing at least four carbon atoms, and having not more than one substituent in the ortho position that contains more than one carbon atom, (c) oil-soluble monoand di-acid esters of o-phosphoric acid having as one phosphate substituent an aliphatic hydrocarbon radical containing 8 to 22 carbon atoms, and as another a member selected from the class consisting of hydrogen and aliphatic hydrocarbon radicals containing 2 to 22 carbon atoms, and (d) oil-soluble hydrocarbon sulfonic acids.

2. The fuel composition of claim 1 where said minor amount is 0.001 to 0.1 percent by weight of the composition.

3. The fuel composition of claim 1 where said minor amount is about 15 to pounds of said quaternary ammonium salt per thousand barrels of said hydrocarbon mixture.

4. The fuel composition of claim lwhere said quaternary ammonium salt is the di(hydrogenated tallow alkyl) dimethylammonium salt of petroleum naphthenic acids.

5. The fuel composition of claim 1 where said quaternary ammonium salt is di(hydrogenated tallow alkyl)dimethylammonium p-tert-octyl phenate.

6. The fuel composition of claim 1 where said quaternary ammonium salt is di(hydrogenated tallow alkyl)dimethylammonium diisooctyl o-phosphate.

7. The fuel composition of claim 1 where said quaternary ammonium salt is his [di(hydrogenated tallow alkyl)] dimethylammonium isooctyl o-phosphate.

8. The fuel composition of claim 1 where the quaternary ammonium salt is a mixture of neutral di(hydrogenated tallow alkyl)dimethylammonium salts of isooctyl and diisooctyl o-phosphoric acids.

9. The fuel composition of claim 1 Where said quaternary ammonium salt is the di(hydrogenated tallow alkyl) dimethylammonium salt of oil-soluble petroleum sulfonic acids.

References Cited in the file of this patent UNITED STATES PATENTS 2,550,982 Eberz May 1, 1951 2,563,506 Werntz Aug. 7, 1951 2,582,733 Zimmer et al. Jan. 15, 1952 2,632,694 Watkins Mar. 24, 1953 2,706,677 Duncan et al. Apr. 19, 1955 2,819,954 Gebelein et al Jan. 14, 1958 2,843,464 Gaston et al. July 15, 1958 2,862,800 Cantrell et al. Dec. 2, 1958 2,863,742 Cantrell et al. Dec. 9, 1958 2,905,541 Gottshall et a1 Sept. 22, 1959 FOREIGN PATENTS 35 6,717 Great Britain Sept. 7, 1941 791,394 Great Britain Mar. 5, 1958 OTHER REFERENCES Petroleum Refining With Chemicals, by Kalichevsky et al., 1956, Elsevier Pub. 00., p. 480.

Claims (1)

1. A GASOLINE MOTOR FUEL COMPOSITION COMPRISING A MAJOR AMOUNT OF A HYDROCARBON MIXTURE BOILING IN THE GASOLINE RANGE, THAT HAS A 50 PERCENT ASTM DISTILLATION POINT NOT GREATER THAN 220*F. AND THAT NORMALLY TENDS TO PROMOTE STALLING OF INTERNAL COMBUSTION ENGINES AND A MINOR AMOUNT, SUFFICIENT TO REDUCE THE ENGINE STALLING CHARACTERISTICS OF SAID COMPOSITION OF A QUATERNARY AMMONIUM SALT WHEREIN TWO OF THE CO-VALENT N-BONDS ARE ATTACHED TO ALIPHATIC HYDROCARBON SUBSTITUENTS CONTAINING 8 TO 22 CARBON ATOMS AND THE REMAINING CO-VALENT NBONDS ARE ATTACHED TO SATURATED ALIPHATIC HYDROCARBON RADICALS CONTAINING 1 TO 4 CARBON ATOMS, AND WHEREIN THE IONIC N-BOND IS ATTACHED TO AN ANIONIC SALT FORMING RADICAL DERIVED FROM A MEMBER SELECTED FROM THE GROUP CONSISTING OF (A) OIL-SOLUBLE ORGANIC MONOCARBOXYLIC ACIDS CONTAINING 7 TO 30 CARBON ATOMS PER MOLECULE, (B) OILSOLUBLE MONOHYDRIC PHENOLS HAVING ATTACHED TO THE AROMATIC NUCLEUS ONE TO THREE HYDROCARBON SUBSTITUENTS CONTAINING AT LEAST FOUR CARBON ATOMS, AND HAVING NOT MORE THAN ONE SUBSTITUENT IN THE ORTHO POSITION THAT CONTAINS MORE THAN ONE CARBON ATOM, (C) OIL-SOLUBLE MONO- AND DI-ACID ESTERS OF O-PHOSPHORIC ACID HAVING AS ONE PHOSPHATO SUBSTITUENT AN ALIPHATIC HYDROCARBON RADICAL CONTAINING 8 TO 22 CARBON ATOMS, AND AS ANOTHER A MEMBER SELECTED FROM THE CLASS CONSISTING OF HYDROGEN AND ALIPHATIC HYDROCARBON RADICALS CONTAINING 2 TO 22 CARBON ATOMS, AND (D) OIL-SOLUBLE HYDROCARBON SULFONIC ACIDS.