Gasoline composition, method and use

1. A gasoline composition comprising, as an additive, one or more quaternary ammonium salt(s) formed by the reaction of a compound of formula (A):

and a compound formed by the reaction of a hydrocarbyl-substituted acylating agent and an amine of formula (B1) or (B2):

wherein R is an optionally substituted alkyl, alkenyl, aryl or alkylaryl group; R 1 is an alkyl, aryl or alkylaryl group having up to 36 carbon atoms; R 2 and R 3 are the same or different alkyl groups having from 1 to 36 carbon atoms; X is an alkylene group having from 1 to 20 carbon atoms; n is from 0 to 20; m is from 1 to 5; and R 4 is hydrogen or a C 1 to C 36 alkyl group;

wherein the compound of formula (A) is an ester of a carboxylic acid selected from the group consisting of a substituted aromatic carboxylic acid, an α-hydroxycarboxylic acid and a polycarboxylic acid.

2. The gasoline composition according to claim 1 wherein the compound of formula (A) is an ester of a carboxylic acid having a pK a of 3.5 or less.

3. The gasoline composition according to claim 1 wherein the compound of formula (A) is an ester of a substituted aromatic carboxylic acid.

4. The gasoline composition according to claim 3 wherein R is a substituted phenyl or naphthyl group substituted with one or more groups selected from the group consisting of optionally substituted alkyl, alkenyl, aryl or carboalkoxy groups, nitro, cyano, hydroxy, SR 5 , NR 5 R 6 or COOR 7 , wherein each of R 5 , R 6 and R 7 is a hydrogen atom or an optionally substituted alkyl, alkenyl, aryl or carboalkoxy groups.

5. The gasoline composition according to claim 1 wherein the quaternary ammonium salt(s) are formed by the reaction of a compound of formula (A) and a compound formed by the reaction of a hydrocarbyl-substituted acylating agent and an amine of formula (B1).

6. The gasoline composition according to claim 1 wherein the hydrocarbyl-substituted acylating agent is polyisobutenyl substituted succinic anhydride.

7. The gasoline composition according to claim 1 further comprising one or more additives selected from the group consisting of:

a) carrier oils;

b) acylated nitrogen compounds which are the reaction product of a carboxylic acid-derived acylating agent and an amine;

c) hydrocarbyl-substituted amines wherein the hydrocarbyl substituent is substantially aliphatic and contains at least 8 carbon atoms;

d) Mannich base additives comprising nitrogen-containing condensates of a phenol, aldehyde and primary or secondary amine; and

e) aromatic esters of a polyalkylphenoxyalkanol.

8. The gasoline composition according to claim 7 wherein component (a) is selected from the group consisting of polyethers and polyetheramines.

9. The gasoline composition according to claim 7 wherein component (d) comprises the reaction product of formaldehyde, an ethylene or polyethylene polyamine, and para-substituted monoalkyl phenol.

10. An additive package which upon addition to gasoline provides a composition as claimed in claim 1 .

11. A method of improving the performance of a direct injection spark ignition gasoline engine comprising adding to gasoline one or more quaternary ammonium salt(s) formed by the reaction of a compound of formula (A):

and a compound formed by the reaction of a hydrocarbyl-substituted acylating agent and an amine of formula (B1) or (B2):

wherein R is an optionally substituted alkyl, alkenyl, aryl or alkylaryl group; R 1 is an alkyl, aryl or alkylaryl group having up to 36 carbon atoms; R 2 and R 3 are the same or different alkyl groups having from 1 to 36 carbon atoms; X is an alkylene group having from 1 to 20 carbon atoms; n is from 0 to 20; m is from 1 to 5; and R 4 is hydrogen or a C 1 to C 36 alkyl group; wherein the compound of formula (A) is an ester of a carboxylic acid selected from the group consisting of a substituted aromatic carboxylic acid, an α-hydroxycarboxylic acid and a polycarboxylic acid; and combusting the additised gasoline.

12. A method of controlling deposits in a direct injection spark ignition gasoline engine comprising adding to gasoline one or more quaternary ammonium salt(s) formed by the reaction of a compound of formula (A):

and a compound formed by the reaction of a hydrocarbyl-substituted acylating agent and an amine of formula (B1) or (B2):

wherein R is an optionally substituted alkyl, alkenyl, aryl or alkylaryl group; R 1 is an alkyl, aryl or alkylaryl group having up to 36 carbon atoms; R 2 and R 3 are the same or different alkyl groups having from 1 to 36 carbon atoms; X is an alkylene group having from 1 to 20 carbon atoms; n is from 0 to 20; m is from 1 to 5; and R 4 is hydrogen or a C 1 to C 36 alkyl group; wherein the compound of formula (A) is an ester of a carboxylic acid selected from the group consisting of a substituted aromatic carboxylic acid, an α-hydroxycarboxylic acid and a polycarboxylic acid; and combusting the additised gasoline.

13. The method according to claim 12 , wherein said controlling deposits comprises reducing existing deposits or reducing deposit formation.

14. A method of controlling deposits and/or of improving the efficiency in a direct injection spark ignition gasoline engine, the method comprising adding into the gasoline to be combusted:

(i) one or more quaternary ammonium salt(s) as defined in claim 1 , and

(ii) optionally, one or more additional components selected from a)-e) as defined in claim 7 .