反应详情

Tetrachlorocyclobutenone, required as a starting material, is obtained with high yields and conversions by a not yet published process from hexachlorocyclobutene and a mixture of sulphuric acid and sulphur trioxide at elevated temperatures, e.g., by reaction of 1 mol hexachlorocyclobutene with approximately 1 mol each of sulphuric acid and sulphur trioxide at a temperature of 80° C. within 5 hours. Hexachlorocyclobutene can be obtained from hexachloro-1,3-butadiene in yields of near 100% of theory (DE-OS No. 26 18 557), corresponding to U.S. Pat. No. 4,115,460), for example by rectifying commercial hexachlorobutadiene at a pressure of from 2 to 100 mm Hg with a reflux ratio of from 300:1 to 600:1, subjecting hexachlorobutadiene remaining in the bottoms to a heat treatment at from 150° to 200° C. and then returning it to the rectifying column together with fresh commercial hexachlorobutadiene while withdrawing the product rich in hexachlorocyclobutene over the top. A suitable starting material is not only pure tetrachlorocyclobutenone but also crude tetrachlorocyclobutenone which may, for example, contain hexachlorobutadiene and hexachlorocyclobutene originating from its process of manufacture.

1. customis obtained
2. customwith high yields