Phosgene → 4-Benzoylbenzoyl chloride

Beteiligte Stoffe

Reaktionsschritte

A total of 3.4 kg of phosgene was passed through a solution of 4 kg of 4-hydroxybenzophenone and 190 g of benzyltrimethylammonium chloride in 11.4 kg of o-xylene over a period of 5 hours, during which time the internal temperature was raised from 95° to 120° C. The introduction of phosgene was then stopped, and stirring was continued for 30 minutes at 115° C. Before the product was worked up, the excess phosgene was expelled with nitrogen. The salt (catalyst) which precipitated toward the end of the reaction was filtered off, and the solvent was removed by distillation. There were obtained 4.9 kg (93%) of yellowish 4-chloroformylbenzophenone having a melting point of 67°-72° C. This crude product having a Cl content of 12.69% (theory=13.60%) was used unpurified as starting material for subsequent reactions.

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