Process for the preparation of isobenzofurandiones

摘要

Isobenzofurandiones are obtained in particularly advantageous manner by the dehydrogenation of tetrahydroisobenzofurandiones in the presence of catalysts at elevated temperature by a process in which distilled tetrahydro-isobenzofurandiones are heated to temperatures of between 120 DEG and 300 DEG C. in the presence of supported palladium and/or platinum catalysts and in the presence of maleic acid derivatives in a trickle-phase or liquid-phase procedure, the temperature in the liquid-phase procedure being increased at a rate of 0.6 DEG to 3 DEG C. per minute above 80 DEG to 110 DEG C.