液相空气氧化法合成单氯代苯酐的工业试验

Method for Industrial Synthesis of Monochlorophthalic Anhydride

报道以邻二甲苯为原料 ,采用液相空气氧化法制备单氯代苯酐工艺。邻二甲苯在三氯化铁催化下和氯气反应得氯代混合物 ,从氯代产物精馏分离出质量分数超过 99%的 3-氯代邻二甲苯和 4 -氯代邻二甲苯混合物。得到的单氯代邻二甲苯以乙酸为溶剂、在 14 0～ 30 0℃、 0 8～ 3 0MPa条件下 ,以钴锰溴体系为催化剂进行液相氧化 ,得单氯代邻苯二甲酸 ,然后脱水成酐 ,得单氯代苯酐混合物 ,精馏分离后得 3-氯代苯酐和 4 -氯代苯酐。单程总收率不低于 75 %。

Synthesis methods for monochlorophthalic anhydride,particularly the process for manufacture of monochlorophthalic anhydride by liquid phase oxidation are reviewed in this paper. o -xylene acting as the starting raw material is chlorinated firstly by chlorine,and by rectification.The content of monochloro- o -xylene can reach 99% by weight.After oxidization in acetic acid solvent in presence of Co,Mn,Br catalysts under 140～300?℃and 0 8～3 0?MPa pressure monochlorophthalic acid is formed.By dehydration and distillation of the acid,4-chlorophthalic anhydride and 3-chlorophthalic anhydride with yield more than 75% are obtained.