| 摘要 |
<p>Halogen- and sulphur-free quaternary ammonium salts of carboxylic acids, useful as cold flow additives in middle distillate fuels, are made by reacting, in the presence of an acid catalyst: (A) a halogen- and sulphur-free tertiary amine that carries at least one alkyl group containing 8 to 40 carbon atoms; and (B) a halogen- and sulphur-free C 1 to C 4 alkyl ester of a carboxylic acid that has a pK a of 3.5 or less.</p> |
