PRODUCTION METHOD FOR BIESTHERS OF 2,2' -1,2-PHENYLENE-BIS-(OXI)¨-BIS ACETIC ACID

摘要

Diesters of 2,2'-(1,2-phenylene-bis(Oxy))-bis-acetic acid of general formula (1) - where R = normal 4-8C, 10C aliphatic gp. or an iso-aliphatic gps: 4-6C and 2-6C (2-ethyl-hexyl) are prepd. by esterification of 2,2' (1,2-phenylene-bis-(Oxy)) -bis-acetic-acid with higher aliphatic alcohols. Esterification is carried out in an azeotropic system using a 20-50% n-aliphatic-alcohol (4-8C) or respectively 4-6C or 2-6C (2-ethyl-hexyl). alcohols. Based on reactants 1-3% catalyst acid is used, namely benzene-sulphonic -or p-toluene-sulphonic- or sulphuric-acid. Benzene, toluene or xylene used in single or double equivalent quantities (based on diols used) is the entraining liq. Reflux period: 1.5-3 hrs. The obtd. suspension is filtered; solvent and excess alcohol is removed by vacuum distillation. The prod. is washed by alkaline soln. and demineralised water, devolatilised and decoloured.