Composition, method and use

1. A quaternary ammonium compound of formula (I):

wherein R 0 , R 1 , R 2 and R 3 is each independently an optionally substituted hydrocarbyl group, X is a linking group, R 4 is an optionally substituted alkylene group, R 5 is hydrogen or an optionally substituted alkyl, alkenyl or aryl group, and n is 0 or a positive integer, provided that n is not 0 when R 5 is hydrogen.

2. A method of preparing a quaternary ammonium salt, the method comprising reacting (a) a tertiary amine of formula R 1 R 2 R 3 N with (b) an acid-derived alkylating agent in the presence of (c) a compound of formula HOOCXCOO—(R 4 O) n —R 5 , wherein R 4 is an optionally substituted alkylene group, R 5 is hydrogen or an optionally substituted alkyl, alkenyl or aryl group, and n is 0 or a positive integer, provided that n is not 0 when R 5 is hydrogen.

3. The method according to claim 2 wherein component (b) is an epoxide.

4. A composition comprising a quaternary ammonium compound of formula (I):

wherein R 0 , R 1 , R 2 and R 3 is each independently an optionally substituted hydrocarbyl group, X is a linking group, R 4 is an optionally substituted alkylene group, R 5 is hydrogen or an optionally substituted alkyl, alkenyl or aryl group, and n is 0 or a positive integer, provided that n is not 0 when R 5 is hydrogen.

5. The composition according to claim 4 wherein the composition is an additive composition for a fuel or lubricating oil.

6. The composition according to claim 4 wherein the composition is a fuel composition.

7. A method of improving the performance of an engine, the method comprising combusting in the engine a fuel composition comprising as an additive a quaternary ammonium compound of formula (I):

wherein R 0 , R 1 , R 2 and R 3 is each independently an optionally substituted hydrocarbyl group, X is a linking group, R 4 is an optionally substituted alkylene group, R 5 is hydrogen or an optionally substituted alkyl, alkenyl or aryl group, and n is 0 or a positive integer, provided that n is not 0 when R 5 is hydrogen.

8. The salt according to claim 1 wherein HOOCXCOO—(R 4 O) n —R 5 is derived from a hydrocarbyl substituted succinic acid or a hydrocarbyl substituted succinic anhydride.

9. The salt according to claim 1 wherein each R 4 is ethylene or propylene.

10. The salt according to claim 1 wherein R 5 is hydrogen and n is at least 1.

11. The salt according to claim 1 wherein R 5 is an optionally substituted alkyl group having 4 to 40 carbon atoms and n is from 0 to 40.

12. The salt according to claim 1 wherein each of R 1 and R 2 is independently an optionally substituted alkyl group having from 1 to 12 carbon atoms.

13. The salt according to claim 1 wherein R 3 is an alkyl or hydroxyalkyl group having 1 to 10 carbon atoms.

14. The salt according to claim 1 wherein R 3 is selected from the group consisting of:

(1) a polyisobutenyl group having a molecular weight of from 100 to 5000;

(2) an optionally substituted alkylene phenol moiety of formula (A) or (B)

wherein n is 0 to 4, R is an optionally substituted hydrocarbyl group, R′ is an optionally substituted alkyl, alkenyl or aryl group; and L is a linking group; and

(3) a succinimide moiety of formula:

wherein R is an optionally substituted hydrocarbyl group and L is a linking group.

15. The salt according to claim 1 wherein R 0 as is a group of formula:

wherein each of R 9 , R 10 , R 11 , R 12 is independently hydrogen or an optionally substituted alkyl, alkenyl or aryl group.

16. The salt according to claim 1 wherein X is an optionally substituted alkylene or arylene group.

17. The salt according to claim 1 wherein the quaternary ammonium compound is the reaction product of:

(a) a tertiary amine of formula R 1 R 2 R 3 N wherein each of, R 1 , R 2 and R 3 is independently an optionally substituted alkyl group having 1 to 12 carbon atoms;

(b) an epoxide selected from the group consisting of: styrene oxide, ethylene oxide, propylene oxide, butylene oxide, epoxyhexane, octene oxide, stilbene oxide, 2-ethylhexyl glycidyl ether, 1,2-epoxydodecane and other alkyl and alkenyl epoxides having 2 to 50 carbon atoms; and

(c) a compound of formula HOOCXCOO—(R 4 O) n —R 5 wherein X is CH 2 CHR or CHRCH 2 wherein R is an optionally substituted hydrocarbyl group; and

n is more than 1, R 4 is an ethylene or propylene group and R 5 is hydrogen; or

n is 0 or and R 5 is a C1 to C20 alkyl group.

18. The salt according to claim 1 wherein the quaternary ammonium compound is the reaction product of:

(a) a tertiary amine of formula R 1 R 2 R 3 N wherein each of, R 1 , R 2 and R 3 is independently an alkyl or hydroxyalkyl group having 1 to 6 carbon atoms;

(b) an epoxide selected from the group consisting of: propylene oxide, butylene oxide and 2-ethylhexyl glycidyl ether; and

(c) a compound of formula HOOCXCOO—(R 4 O) n —R 5 which is the reaction product of a succinic acid or anhydride having a C 20 to C 24 alkyl or alkenyl substituent and an alcohol selected from the group consisting of: polypropylene glycol having a number average molecular weight of 300 to 800, 2-ethylhexanol and butanol.

19. The composition according to claim 4 wherein the composition is a lubricating composition.

20. The composition according to claim 4 wherein the composition is a gasoline fuel composition.

21. The composition according to claim 20 wherein the gasoline fuel composition comprises one or more further 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;

e) aromatic esters of a polyalkylphenoxyalkanol; and

f) additional quaternary ammonium salts.

22. The composition according to claim 20 wherein the gasoline fuel composition comprises a mixture of two or more quarternary ammonium salt additives.

23. The method as defined in claim 7 wherein the additive is used as a detergent to combat deposits in a gasoline fuel composition in a spark ignition engine.

24. The method according to claim 7 wherein the engine is a direct injection spark ignition engine.

25. The method according to claim 7 which achieves “keep clean” performance.

26. The method according to claim 7 which achieves “clean up” performance.

27. The method according to claim 7 wherein the deposits are injector deposits.

28. The method according to claim 27 wherein the deposits are internal injector deposits.

29. The method according to claim 7 which combats intake valve deposits.

30. The method according to claim 7 which achieves an improvement in performance of one or more of:

improved fuel economy;

reduced maintenance;

less frequent overhaul or replacement of injectors;

improved driveability;

improved power; or

improved acceleration.