US3336123A - Gasoline anti-stalling composition - Google Patents

Description

United States Patent 3,336,123 GASOLINE ANTI-STALLIN G COMPOSITION Howard Dudley Clile Hill, Wilmington, Del., assignor to E. I. du Pont de Nemours and Company, Wilmington, DeL, a corporation of Delaware No Drawing. Filed June 24, 1964, Ser. No. 377,527 6 Claims. (Cl. 44-56) The present invention is directed to an improved gasoline composition containing an additive which not only prevents stalling due to carburetor icing but also reduces deposition of objectionable gums and carbonaceous materials in the carburetors of internal combustion engines.

A common occurrence in the operation of an internal combustion engine is frequent engine stalling in climates Where high humidity is common with temperatures between about 30" F. and 60 F. This stalling is attributed to the formation of ice particles in the carburetor, especially on the throttle plate and surrounding body walls. The formation of ice in the careburetor, known as carburetor icing, is caused by a temperature reduction in the metal parts of the carburetor as the fuel vaporizes. This lower temperature in turn causes the moisture in the air coming into the carburetor to condense and freeze at the edge of the throttle plate and on the air bleeds of the carburetor. Ice formation at the edge of the throttle plate reduces the flow of air to the engine thereby causing the engine to stall. On the other hand, ice formation on the air bleeds or venturi causes the engine to stall from excessively rich mixtures of gasoline.

Ice formation also occurs in the emulsion tube type carburetor which is used extensively in foreign-make cars. This type of carburetor comprises an emulsion tube in which the air and gasoline are mixed, metered and then carbureted. Ice initially forms at the air correction inlet of the emulsion tube and eventually causes the engine to stall.

Frequent engine stalling also results from operating conditions at idling speeds in heavy stop-and-go trafiic. The reason for the engine to stall in such traffic is due mainly to an accumulation of deposits on the walls of the carburetor throttle body which is below the closed portion of the throttle plate. Deposits of such foreign materials are able to enter the carburetor during periods of engine idling because the air filter at idling speeds is relatively inelfective. Most contaminants which enter the carburetor are those thrown out of the engine through the crankcase blowby. These contaminants remain trapped under the hood While the engine is idling and the car is stopped. Other sources of contaminants are exhaust fumes from the carahead and the normal smoke and dust which accumulate in the air as a result of heavy traffic conditions. A common remedy used to eliminate this problem is the adjustment of the engine to higher idling speeds. Thisaction, however, is uneconomical since it wastes gasoline.

The problem of carburetor icing has become more pronounced in recent years due to a trend in the use of more volatile gasolines which provide good cold-starting and warm-up characteristics. The tendency for carburetor icing has been closely correlated to the degree of volatility of the gasoline. The gasolines most affected by carburetor icing and therefore the gasolines to which this invention is directed are characterized by having a mid-boiling point of less than about 245 F. as determined by A.S.T.M. distillation method.

It is, therefore, an object of the present invention to provide an improved gasoline for internal combustion engines which reduces engine stalling not only by pre venting ice formation in the carburetor but also by reducing depositions of objectionable gum and other carbonaceous materials in the carburetor.

More specifically, the present invention is directed to a gasoline composition containing as an anti-stalling agent and effective amount of a salt of (a) linoleic acid dimer or trimer and (b) a dialkylaminopropyl carboxamide of the formula AcNHCH CH CH -NRR', wherein Ac is a C to C fatty or naphthenyl acyl group and R and R are the same or different alkyl groups of 1 to 4 carbon atoms.

The linoleic acid dimer and trimer salts of the N-(3- dialkylaminopropyl) fatty and naphthenic acid amides utilized in the present invention may be prepared according to any of the methods of the art. For instance, the salts can be formed by neutralizing the acid with the amine. This is accomplished by thoroughly mixing the two components at slightly elevated temperatures in the range of from 30 C. to 50 C. The salt may be prepared in a solvent such as methanol, toluene, xylene or kerosene in sufiicient quantity to make a 50 to percent by weight solution of the salt. The preferred solvent is methanol. Such a concentrate is a convenient means for handling the salt and facilitates the blending of the salt composition into the base gasoline. The salts of the present invention which are especially effective as anti-stalling agents and therefore preferred are the linoleic acid dimer salt of N-(B-dimethylaminopropyl) oleamide, the linoleic acid dimer salt of N-(3-dimethylaminopropyl) tallamide, and the linoleic acid trimer salt of N-(3-dimethylaminopropyl) tallamide.

Neither the amine nor acid components of the salts utilized in the present invention are alone effective as anti-icing or detergent agent in gasoline. Thus, since the salt is the active ingredient in the gasoline composition, the effectiveness of the gasoline to prevent stalling is directly dependent on the concentration of the neutral salt in the gasoline. However, excess amounts of the amine or acid with the salt are not detrimental to the performance of the salt and usually, due to the method of preparation, these materials are present with the salt additive. In general, a sufiicient amount of the amine component is employed to neutralize from 1 to 2 carboxylic acid groups of the dimer acid and from 1 to 3 carboxylic acid groups of the trimer acid. Usually at least one half and preferably all of the carboxylic acid groups are neutralized, i.e., one amine equivalent is used for each carboxylic acid equivalent to make the neutral salt. Excess of the amino amide may be employed, but, as hereinbefore stated, is unnecessary and tends to be wasteful.

The amount of salt added to the gasoline is not critical as long as it is suflicient to improve the antistalling characteristics of the gasoline. The preferred amount of the salt added to the gasoline is from about 0.001% to about 0.02% by Weight based on the weight of the gasoline.

The fatty acid amino amides are conveniently obtained as described in US. Patent 2,805,925 by condensing one mole of the di-C -C -alkylaminopropylamide with one mole of a C C aliphatic or cycloaliphatic carboxylic acid, such as pelargonic, oleic, stearic and naphthenic acids, tall oil (a mixture of oleic, linoleic, and rosin acids) and coconut oil fatty acids which consist principally of an aliphatic acid containing 12 carbon atoms together with lesser amounts of other straight-chain acids containing an even number of from 8 to 18 carbon atoms. The naphthenic acids utilized to form the amides in the present invention are normally obtained from petroleum and may be defined chemically as monobasic carobxylic acids, RCOOH, where R is a naphthenic radical. The naphthenic radicals are predominantly derived from cyclopentane, homologs of cyclopentane and their bicyclic derivatives, and to a lesser degree from cyclohexane. The carboxyl group is usually linked to a paraffiuic side-chain but may be attached directly to a ring carbon atom. The ring,

which may be monoand bicyclic, may have alkyl substituents. Typical commercial naphthenic acids are mixtures of cycloaliphatic acids containing from about 8 to 18 carbon atoms and boiling between about 200 C. and 300 C. at atmospheric pressure, or between about 160 C. and 200 C. at 6 mm. of mercury pressure. A suitable typical mixture of naphthenic acids has an average acid number of approximately 247, corresponding to an average molecular weight of about 227 (about 13 carbon atoms in the molecule). Representative examples of naphthenic acids are 3-cyclopentylpropionic, 4-cyclohexylbutyric, l-methylcyclohexane carboxylic, 3,3,4-trimethylcyclopentylacetic, and decalin-Z-carboxylic acid. Technical grades of the acids may be used in the condensation. The condensation normally is effected between 120 C. and 200 C. and one mole equivalent of water is evolved. Use of a hydrocarbon solvent facilities the removal of the water by azeotropic distillation. Such solvent, as desired, can be either left in the product or separated from it by distillation.

The linoleic acid dimer and linoleic acid trimer utilized in this invention are commercially available materials. The preparation of such a dimer and trimer is described in US. Patent 2,482,761 and in an article by Charles G. Goebel, Journal of the American Oil Chemists Society, vol. 24, pp. 65-8 (1947). Since commercial linoleic acid may contain small amounts of other fatty acids, dimers or trimers of these acids may also be present in the product used in this invention. It is also well known in the art that the linoleic dimer acids may contain from small to substantial amounts of linoleic trimer acid and also minor amounts of unreacted acid. Likewise, the commercial linoleic trimer acid may contain from small to substantial amounts of linoleic dimer acid and also minor amounts of unreacted acids. Commercial linoleic acid dimers or timers which are substantially all dimer acid or trimer acid, or mixtures of the two, are suitable for use in the invention.

Naturally, the gasoline compositions of this invention may contain all the additives incorporated in modern gasoline in addition to the subject anti-stalling additive. Such additives as anti-knock agents, anti-oxidants, dyes, and metal deactivators do not affect the performance of the salts of this invention and are compatible in gasolines with the subject anti-stalling agents.

For a clearer understanding of the present invention, the following specific examples are given. These examples are intended to be illustrative of the present invention and not in limitation thereof in any respect. All parts are by weight unless otherwise specified.

EXAMPLE I Gasoline samples containing the neutral salts of this invention were prepared for testing in an internal combustion engine. The tests were made to determine the effect of the additives of the present invention in improving the characteristics of gasolines in respect to their abilities to prevent carburetor icing and carburetor deposits. The samples were prepared by adding to the gasoline small amounts of technical grades of linoleic acid dimer or linoleic acid trimer salts of aliphatic acid amides of N-(3-dimethylarninopropyl) amine and/or N-(3-di-n-butylaminopropyl) amine, as more fully described in Tables I, II, and III below.

The gasoline used in the tests was commercial available and had the following inspection data:

Reid vapor pressure p.s.i. 13.0 A.S.T.M. distillation (D86), F.:

End point 406 The following is a brief discussion of the test procedures and equipment used to evaluate these samples.

Anti-icing test Type of Carburetor Throttle Plate Emulsion Tube Intake air, F 38-40 34-60. Relative humidity, percent- 98-100..- 98-100. Engine load, horsepower 10 15. Engine speed, r.p.m... 1,500 33 high 1,500 initially.

spee Idle speed, r.p.m 350 FigeIIE Temperatui'e to carburetor,

(a) Throttle plate carburetor The operating time of the engine was varied at the conditions described above, using the time required for stalling as a measure of the fuels tendency to cause or prevent stalling due to carburetor icing. All runs were started after soaking the throttle plate with methanol for 0.5 minute at a temperature of 40 F. The operating time selected for the engine depended on the ice-forming tendencies of the fuel. Operating times at the 1500 r.p.m. engine speed were usually in the 0.5-1.5 minute range for uninhibited base fuels. At the end of the 1500 r.p.m. portion of the operating cycle, the throttle was cut back to idle position. If no stall occurred within 30 seconds at idle, the run was repeated for a longer period at 1500 r.p.m. until a time was found when the engine stalled within 30 seconds after converting back to idle. The anti-stall rating or stall time of a gasoline was defined as the longest 1500 r.p.m. run (to the nearest 0.25 minute) followed by a complete 30-second idle period without stalling. A stall time of 3 or more minutes was considered excellent performance.

(b) Emulsion tube carburetor A Solex, Model No. 32 PBICA, single barrel, down draft carburetor adapted to 12" extension of 1 /2" pipe on intake manifold, was substiuted for the throttle plate carburetor and the engine was operated under the conditions as listed. Under these conditions, using the Solex emulsion type carburetor, the engine does not stall completely. The engine is operated for 20 minutes on the test fuel at an initial speed of 1500 r.p.m., and the reduction in engine speed is taken as a measure of the effectiveness of the anti-icing agent. A winter grade base fuel may result in a loss in speed of over 600 r.p.m. during the 20-minute period. A reduction of not more than 50 r.p.m. on operating for 20 minutes is considered excellent antiicing performance.

For the purposes of demonstrating the eifectivness of the subject additives, runs were made on gasolines both with and without additive. The results of the tests are set forth in the following tables. Table I contains the results obtained while operating the engine with the throttle plate carburetor and Table II contains the results obtained with the Solex carburetor or emulsion tube type carburetor. Table III shows that the /2 neutral, /3 neutral and neutral N-(3-dimethylaminopropyl) oleamide salts of linoleic acid dimer are effective anti-icing agents in the emulsion tube carburetor and also that the effectiveness of the salt is not diminished by the presence in gasoline of additional quantities of the linoleic acid dimer and trimer or amine amide. Table III also shows the effect of the concentration of the neutral salt on the anti-icing characteristics of the gasoline composition in the emulsion tube type carburetor engine. 5

TABLE 1 Effect of Additive on Engine Stalling Due to Carburetor Icing Using the Throttle Plate Carburetor Test Additive Engine Additive 1 Cone., Wt. Stall Percent Time, Minutes Base Gasoline, Control None 0.25

Linoleic Acid dimer salt of N -(3-di u.1ethyl- 0.0067 1.

aminopropyl) tallamide 0. 0093 2. 00 0.0150 3.00

Linoleic Acid dimer salt of N -(3-dimethy1- 0. 0040 1.00 aminopropyl) oleamide 0.0150 3. 00

A 1 In each instance the indicated salt involved sufiicient amine to neu- 2O tralize all the carboxylic acid groups of the acid component.

TABLE IL-EFFECT OF ADDITIVE ON CARBURETOR ICING USING THE EMULSION TUBE TYPE CARB U- RETOR TEST 25 Engine r.p.m.

Additive Loss During Additive 1 C0nc., Wt. 20 Minutes Percent Operation under Test Conditions Base Gasoline, Control None 600 N-(3-dimetliylaminopropyl) stearamide 0. 004 600 N-(3-dimethylaminopropyl) tallamide- 0.004 600 N-(3-dibutylaminopropyl) oleamide.-

Linolcie acid dlmer 0 (no 175 Linoleic acid trimer 0. 004 150 Linoleic acid dimer salt of N- (ddimethylaminopropyl) stearamide 0. 004 0 Linoleic acid dimer salt of N -(3-dirnethylaminopropyl) naphthamide 0. 004 0 Linoleic acid dimer salt of N-(3- dimethylamiuoproply) tallamide 0. 004 50 Linoleic acid dimer salt of N-(3-di- 4O methylaminopropyl) pelargonamide- 0. 0053 50 Linoleic acid dimer salt of N-(3- dimethylaminopropyl) oleamide 0. 004 10 Linoleic acid dimer salt of N -(3- dibutylaminopropyl) oleamide 0.010 50 Linoleic acid trimer salt of N-(3- dimethylaminopropyl) tallamide 0. 004 25 Linoleic acid trimer salt neutral) of N-(3-dimethylaminopropyl) tallam1de o. 004 25 1 In each salt instance, except where indicated, the salt involved sufficient amine to neutralize all the carboxylie acid groups of the acid component.

TABLE n1.nrrncr or ADDI'IIVE NEUTRALITY AND CONCENTRATION ON ANTI-ICING USING THE EMUL- SION TUBE TYPE CARBURETOR TEST Engine r.p.m. Loss During 20 Additives and Concentration Minutes Operation under Test Conditions Base Gasoline, Control (No additive) 600 0.0005 wt. Linoleio acid dimer salt (neutral) of N-(3- dimethylaminopropyl) oleamide plus 0.002 wt. N- 6 (B-dimethylaminopropyl) oleamide 225 0 0.0018 wt. Linoleic acid dimer salt (neutral) of N-(S- dimethylaminopropyl) oleamide plus 0.0032 wt. N (3-dimethylaminopropyl) oleamide 25 0.0021 wt. Linoleic acid dimer salt (neutral) of N 3 dimethylaminopropyl) oleamide plus 0.0012 wt. N- (3-dimethyla'rninopropyl) oleamide 50 0.0024 wt. Linoleic acid dimer salt (neutral) of N-(3- dimethylaminopropyl) oleamide plus 0.0045 wt. N (3-dimethylaminopropyl) oleamide 50 0.0037 wt. Linoleic acid dimer salt (neutral) of N-(3- dimethylaminopropyl) oleamide plus 0.0067 wt. N- (3-dimethylaminopropyl) oleamide 0 0.0028 wt. Linoleic acid dimer salt neutral) oi N (3-dimethylaminopropyl) oleamide 10 0.0012 wt. Linoleic acid dimer salt (neutral) of N-(3- 7O dimethylaminopropyl) oleamide plus 0.0022 wt. N-(3-dimethylaminopropyl) oleamide 125 0.0013 Wt. Linoleic acid dlmer salt (M neutral) of N- (3-dimethylaminopropyl) oleamide plus 0.001 wt. linoleic acid dimer 125 6 EXAMPLE H A commercial premium gasoline with a Reid vapor pressure of 11.0 lbs. and a mid-boiling point of 228 F. was found to have a stall time of 0.75 minute when evaluated in the throttle plate carburetor anti-stall test described in Example I. The same gasoline to which was added 0.0026 weight percent of the linoleic acid dimer salt of N-(3-dimethylaminopropyl) tallamide gave a stall time of 3.00 minutes, which represents excellent antiicing performance.

EXAMPLE III A motor gasoline with a Reid vapor pressure of 7.1 lbs. and a mid-boiling point of 242 F. was found to cause an engine r.p.m. loss of 300 during 20 minutes operation when evaluated for anti-icing eifect in the emulsion tube carburetor test described in Example I. The addition of only 0.0014 weight percent of the linoleic acid dimer salt of N-(3-dimethylaminopropyl) oleamide caused the engine to operate on the fuel for 20 minutes under the test conditions with no r.p.m. loss.

It is apparent from the preceding examples that the linoleic acid dimer and linoleic acid trimer salts of the fatty acid amino amides of the present invention are very effective in suppressing carburetor icing, whereas, as shown in Table II, the fatty acid amino amides and the dimer and trimer acids alone are markedly less effective.

EXAMPLE IV The linoleic acid-dimer and linoleic acid trimer salts of the fatty acid amide amines hereinabove described in this invention are also efrectve in improving the characteristics of gasoline in respect to their ability to reduce or prevent the deposition of objectionable gums and/ or carbonaceous materials in the carburetor.

The effect of the additives on the carburetor detergency properties of the gasoline was demonstrated using an Onan test engine equipped with a Tillotsen carburetor modified by the use of removable inserts around the throttle plate. Throughout the test, a portion of the exhaust gases of a second single cylinder engine running at a constant speed of 1700 r.p.m. was introduced into the test carburetor. The test engine was cycled one minute at open throttle under dynamometer load and then for two minutes at idle of 11001- r.p.m. for a period of two hours. At the conclusion of the test the inserts were removed and rated on a scale from 0 to 10 where 10 represented bright and shiny and 0 represented very heavy black deposits.

The base gasoline described in Example I without the additive was evaluated in the carburetor detergency test and found to give a carburetor inserts rating of 4.0. The same gasoline to which was added 0.006 weight percent of the linoleic acid dimer salt of N-(3-dimethylaminopropyl) tallamide gave a carburetor detergency test rating of 9.5, which is considered excellent detergency performance.

EXAMPLE V A commercial regular gasoline with a Reid vapor pressure of 11.0 lbs. and a mid-boiling point of 210 F. gave a carburetor detergency performance rating of 6.4 when evaluated in the carburetor detergency test described in Example IV. The same gasoline containing 0.005 Weight percent of the linoleic acid dimer salt of N-(3-dimethylaminopropyl) tallamide was found to have a carburetor detergency performance rating of 9.5.

It is to be understood that the preceding examples are representative and that said examples may be varied within the scope of the total specification, as understood by one skilled in the art, to produce essentially the same results.

As many apparently widely different embodiments of this invention may be made without departing from the spirit and scope thereof it is to be understood that this wherein Ac represents a C to C acyl selected from the group consisting of aliphatic and cycloaliphatic acids and R and R are individually selected from alkyl groups of 1 to 4 carbon atoms.

2. A gasoline composition comprising a gasoline and as an anti-stalling agent from about 0.001% to about 0.02% by weight based on the weight of the gasoline of a salt of (a) an acid selected from the group consisting of linoleic acid dimer and linoleic acid trimer and (b) a dialkylaminopropyl carboxamide of the formula AC-NH-CH CH -CH NRR' wherein Ac represents a C to C acyl selected from the group consisting of aliphatic and cycloaliphatic acids and R and R are individually selected from the alkyl groups of 1 to 4 carbon atoms.

3. A gasoline composition comprising a gasoline and as an anti-stalling agent from about 0.001% to about 8 0.02% of the linoleic acid dimer salt of N-(B-dimethylaminopropyl) oleamide.

4. A gasoline composition comprising a gasoline and as an anti-stalling agent from about 0.001% to about 0.02% of the linoleic acid dimer salt of N-(3-dimethylaminopropyl) tallamide.

5. A gasoline composition comprising a gasoline and as an anti-stalling agent from about 0.001% to about 0.02% of the linoleic acid trimer salt of N-(3-dirnethylaminopropyl) tallamide.

6. A concentrated solution of an anti-stalling additive for gasoline comprising a salt of (a) an acid selected from the group consisting of linoleic acid dimer and linoleic acid trirner and (b) a dialkylaminopropyl carboxamide of the formula Ac-NH-CH CH CH NRR', wherein Ac represents a C to C acyl selected from the group consisting of aliphatic and cycloaliphatic acids and R and R are individually selected from alkyl groups of 1 to 4 carbon atoms and methanol, said salt being in sufficient quantity to make a to by weight solution of the salt.

References Cited UNITED STATES PATENTS 2,914,479 11/1959 Tom et al. 44-66 X 2,922,707 1/ 1960 Lindstrom et al. 44-66 3,007,782 11/1961 Brown et al. 44-56 3,251,663 5/1966 Andress et al. 44-66 DANIEL E. WYMAN, Primary Examiner.

W. I. SHINE, Assistant Examiner.

Claims (1)

1. 6. A CONCENTRATED SOLUTION OF AN ANTI-STALLING ADDITIVE FOR GASOLINE COMPRISING A SALT OF (A) AN ACID SELECTED FROM THE GROUP CONSISTING OF LINOLEIC ACID DIMER AND LINOLEIC ACID TRIMER AND (B) A DIALKYLAMINOPROPYL CARBOXAMIDE OF THE FORMULA AC-NH-CH2CH2-CH2NRR'', WHEREIN AC REPRESENTS A C8 TO C18 ACYL SELECTED FROM THE GROUP CONSISTING OF ALIPHATIC AND CYCLOALIPHTIC ACIDS AND R AND R'' ARE INDIVIDUALLY SELECTED FROM ALKYL GROUPS OF 1 TO 4 CARBON ATOMS AND METHANOL, SAID SALT BEING IN SUFFICIENT QUANTITY TO MAKE A 50 TO 80% BY WEIGHT SOLUTION OF THE SALT.

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