Process for making aromatic acids

Abstract From the Canadian patent

A process for making an aromatic carboxylic acid of high purity by feeding an essentially equilibrium hydrolysis mixture of an aromatic nitrile to a reactive distillation column operated at a temperature of from about 200°C. to about 325°C. at autogenous pressure where the equilibrium mixture is subjected simultaneously to countercurrent contact with steam, ammonia and carbon dioxide, and to further hydrolysis and distillation of ammonia, removing water vapor, carbon dioxide and ammonia from the top of the column, subjecting remaining equilibrium hydrolysis mixture to further hydrolysis and distillation in a reboiler to which carbon dioxide is added returning carbon dioxide, water and …