Use of specific derivatives of quaternized nitrogen compounds as additives in fuels and lubricants

A process, comprising operating a diesel engine with a fuel comprising an additive comprising a quaternized nitrogen compound, wherein presence of the additive reduces, prevents, or both, deposits in the intake system of the diesel engine,

• wherein the quaternized nitrogen compound is obtained by:
• a) reacting a quaternizable nitrogen compound comprising a quaternizable amino group with a quaternizing agent which converts the quaternizable amino group to a quaternary ammonium group, the quaternizing agent being a C1-C4-alkyl ester of an aliphatic, cycloaromatic or cycloaliphatic polycarboxylic acid, to obtain a quaternization product;
• and
• b) transesterifying or amidating a remaining ester group of the quaternization product,
• wherein:
• the quaternizing agent is an alkyl ester of an aliphatic, cycloaromatic or cycloaliphatic polycarboxylic acid;
• the transesterifying occurs with
• a saturated or unsaturated, linear, branched or cyclic, aliphatic C1-C28 mono-alcohol or polyol,
• a partly esterified polyol having at least one free hydroxyl group, or
• a polyisobutylene alcohol obtained by hydroformylating and reducing a polyisobutene, having a molecular mass ranging from 150 to 5000, found by gel permeation chromatography (THF solvent, polystyrene standard) of the polyisobutylene alcohol,
• or
• the transesterifying occurs by replacing a methyl or ethyl group in the remaining ester group of the quaternization product with a hydrocarbyl radical having 5 to 50 carbon atoms from a long-chain alcohol;
• and
• the amidating occurs with
• a saturated or unsaturated linear, branched or cyclic, aliphatic, primary or secondary aliphatic C5-C28 mono- or polyamine, or
• a polyisobutyleneamine.