| 摘要 |
PURPOSE:To readily obtain the subject compound industrially useful as a raw material, etc., of a high heat resistance resin, etc., in a high yield by heating and dehidrating phthalic acid and/or phthalic anhydride, sulfuric acid, sulfuric anhydride, sulfophthalic acid and/or sulfophthalic anhydride. CONSTITUTION:Dehydration by heating is carried out between (A) phthalic acid and/or phthalic anhydride and (B) one or more sulfurcontaining compounds selected from sulfuric acid, sulfuric anhydride, sulfophthalic acid and sulfophthalic anhydride, preferably in the presence of (C) one or more compounds selected from tungstic acid, molybdic acid and heteropoly-acids thereof, (D) one or more compounds selected from phosphorous oxide, phosphoric acid and polyphosphoric acids and/or (E) a super-acid resin to very readily obtain the objective tetracarboxydiphenyl sulfone dianhydride in a high yield by a direct dimerization of sulfone using the above-mentioned economical raw material readily available in an industrial scale. |
