Procedure for the production of alkyl Esters of acids or Aromatic - hidroxicarboxilicos

摘要

Aromatic o-hydroxycarboxylic acid esters are made by esterifying aromatic o-hydroxycarboxylic acids with primary alcohols in the presence of acid esterification catalysts (a) at temps. b.pt of the primary alcohol and (b) under such conditions that only a small amt. of the alcohol is present at any time. In a typical process the acid (e.g. sali-cyclic acid) and 1-6 wt.% acid catalyst (H2SO4, benzene sulphonic acid, toluene sulphonic acid etc.) are mixed with excess amt. of alcohol e.g. methanol, ethanol, propanol, n-butanol, isobutanol etc. and the mixt. heated to 80-200 degrees C. A large proportion of the alcohol distils off and the acid melts and forms a soln or suspension. The reaction then proceeds with addn of alcohol continuously while a water/alcohol mixt. distils off.