Verfahren zur Gewinnung von Trimellitsaeure und/oder Trimellitsaeureanhydrid

摘要

1,197,947. Trimellitic acid. DYNAMIT NOBEL A.G. 20 Oct., 1967 [20 Oct., 1966], No. 47898/67. Heading C2C. Trimellitic acid is prepared by fractionally distilling under reduced pressure the residue obtained in the manufacture of dimethyl terephthalate by oxidation of p-xylene via methyl p-toluate in the liquid phase, to obtain a distillation fraction relatively rich in methyl ester of trimellitic acid, saponifying this fraction and precipitating the resultant trimellitic acid. The saponification step may be effected in either acid or alkaline media. The trimellitic acid produced may be converted to trimellitic anhydride.