Process for the preparation of isobutyric anhydride

摘要

The invention relates to a process for the preparation of isobutyric anhydride, in which propylene is first carbonylated in the presence of a substantial molar excess of liquid anhydrous hydrogen fluoride, resulting in a reaction mixture of isobutyryl fluoride and unconverted HF. In order to recover the HF for recycling into the reaction cycle, the reaction mixture is then distilled. The isobutyryl fluoride residue is partially hydrolysed in the presence of an HF acceptor, giving a hydrolysis product consisting essentially of isobutyryl fluoride, isobutyric anhydride and a hydrogen fluoride complex of the acceptor mentioned. After removal of the solid complex, the hydrolysis product is subjected to fractional distillation, giving a top fraction of isobutyryl fluoride which is again recycled into the reaction cycle in order to be fed into the hydrolysis reaction.