Di:alkyl phthalate and adipate prodn. - by completing esterification of partially reacted mixt. in a flooded column; useful as plasticisers

摘要

Complete esterification of dicarboxylic acids comprises introducing a mixt. of diester (I), monoester (II), alcohol (III) and esterification catalyst into a column at b.pt. of (III) or a temp. up to 40 degrees C. higher. The liq. mixt. passes up the flooded column in the same direction as water and alcohol vapour. The rise speed of the vapour bubbles is reduced, and water and (III) are removed as overhead, while crude (I) is taken off as a side-stream below the column head. The starting mixt. comprises 50-70 wt. % (ROOC)2A (A=1,2-phenylene or (CH2)4; R=4-11C alkyl); 3-15% HOOC.R.COOR; 27-35% ROH, and 0.05-0.1 wt. % catalyst. No azeotropic agent is needed to remove the water and a uniform temp. profile and constant boiling conditions are maintained in the column, so fractionation is avoided. Back-saponification of the prodn. does not occur.