Diesel fuel compositions for high pressure fuel systems
A diesel fuel composition comprising, as an additive, a quaternary ammonium salt 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 a C 1 to C 22 alkyl, aryl or alkylaryl group; R 2 and R 3 are the same or different alkyl groups having from 1 to 22 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 22 alkyl group.
1. A diesel fuel composition comprising, as an additive, a quaternary ammonium salt 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 a C 1 to C 22 alkyl, aryl or alkylaryl group; R 2 and R 3 are the same or different alkyl groups having from 1 to 22 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 22 alkyl group; and
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 diesel fuel compositions 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 diesel fuel composition according to claim 1 wherein the compound of formula (A) is an ester of a substituted aromatic carboxylic acid.
4. The diesel fuel composition according to claim 3 wherein R is a substituted aryl group having 6 to 10 carbon atoms substituted with one or more groups selected from carboalkoxy, nitro, cyano, hydroxy SR 5 or NR 5 R 6 , wherein R 5 and R 6 are each independently hydrogen or an optionally substituted C 1 to C 22 alkyl group.
5. The diesel fuel composition according to claim 4 wherein R is 2-hydroxyphenyl or 2-aminophenyl and R 1 is methyl.
6. The diesel fuel composition according to claim 1 wherein the compound of formula (A) is an ester of an α-hydroxycarboxylic acid.
7. The diesel fuel composition according to claim 1 wherein the compound of formula (A) is an ester of a polycarboxylic acid.
8. The diesel fuel composition according to claim 1 wherein R 2 and R 3 is each independently C 1 to C 8 alkyl and X is an alkylene group having 2 to 5 carbon atoms.
9. The diesel fuel composition according to claim 1 which comprises a further additive, this further additive being the product of a Mannich reaction between:
(a) an aldehyde;
(b) a polyamine; and
(c) an optionally substituted phenol.
10. The diesel fuel composition according to claim 9 wherein component (a) comprises formaldehyde, component (b) comprises a polyethylene polyamine and component (c) comprises a para-substituted monoalkyl phenol.
11. An additive package which upon addition to a diesel fuel provides a composition as claimed in claim 1 .
12. The diesel fuel composition according to claim 1 further comprising a metal-containing fuel-borne catalyst.
13. The diesel fuel composition according to claim 12 wherein the catalyst is based on metals selected from the group consisting of iron, cerium, group I metals, group II metals, and mixtures thereof.
14. The diesel fuel composition according to claim 13 wherein the group I metal or group II metal is selected from the group consisting of calcium and strontium.
15. The diesel fuel composition according to claim 12 wherein the catalyst is selected from the group consisting of platinum and manganese.
16. A method for improving the engine performance of a diesel engine, comprising:
adding a quaternary ammonium salt additive to a diesel composition, wherein the quaternary ammonium salt is 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 a C 1 to C 22 alkyl, aryl or alkylaryl group; R 2 and R 3 are the same or different alkyl groups having from 1 to 22 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 22 alkyl group; and
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.
17. The method of claim 16 wherein the diesel fuel composition further comprises an additive formed by a Mannich reaction between
(a) an aldehyde;
(b) a polyamine; and
(c) an optionally substituted phenol.
18. The method of claim 16 wherein the diesel engine comprises a high pressure fuel system.
19. The method of claim 16 , wherein the diesel engine is a traditional diesel engine.
20. The method of claim 16 further comprising providing “clean up” performance.
21. The method according to claim 16 further comprising adding a metal-containing fuel-borne catalyst to aid with regeneration of particulate traps.
22. The method according to claim 21 wherein the catalyst is based on metals selected from the group consisting of iron, cerium, group I metals, group II metals, and mixtures thereof.
23. The method according to claim 22 wherein the group I metal or group II metal is selected from the group consisting of calcium and strontium.
24. The method according to claim 21 wherein the catalyst is selected from the group consisting of platinum and manganese.