Composition of matter based on alkyl benzyl esters

A process for preparation of ester mixtures comprising

• a) from 80 to 99% by weight of one or more esters of the structure (R1OOC)n-Z-(COOR2)p
• b) from 1 to 20% by weight of an ester of the structure (R2OOC)m-Z
• where the total of the % by weight values derived from the components of the ester mixtures is 100
• and
• wherein
• R1 is a straight-chain or branched C1-C20-alkyl moiety,
• R2 is a benzyl moiety optionally substituted with C1-C4-alkyl or with halogen,
• Z is an m-valent aromatic C6-C10-hydrocarbon moiety,
• m is a number from 3 to 4 and
• each of n and p is a number from 1 to 3, with the proviso that n+p=m,
• by reacting at least one aromatic tri- or tetrabasic polycarboxylic acid or a derivative thereof, at least one benzyl halide and at least one aliphatic alcohol with one another at temperatures of from 50 to 300° C. and at pressures of from 2 mbar to 10 bar in the presence of an inorganic base and of a substoichiometric amount of a phase-transfer catalyst.