| 摘要 |
A quaternary ammonium compound of formula (X): where each of R1-R4 is independently an optionally substituted alkyl, alkenyl, or aryl group having fewer than 8 carbon atoms and R5 is hydrogen or an optionally substituted hydrocarbyl group. Also claimed is a method of preparing a quaternary ammonium salt comprising reacting a tertiary amine of formula R1R2R3N with a quaternizing agent selected from: an ester of formula R5COOR4; a carbonate compound of formula R0OCOOR4 and then a carboxylic acid of formula R5COOH; and an epoxide having fewer than 8 carbon atoms and a carboxylic acid of formula R5COOH, where R0 is an optionally substituted hydrocarbyl group. Preferably the compounds as defined above are used as additives in a fuel composition, preferably a diesel or gasoline fuel. Also claimed is the use of a quaternary ammonium compound as defined above to improve the performance of an engine, preferably by combating deposits in the engine. Preferably the compounds or compositions may be used to achieve keep clean or clean up performance. |
