申请人:Hoechst Aktiengesellschaft
公开号:US05481032A1
公开(公告)日:1996-01-02
A process for the preparation of halogenated benzoic acids of formula (1): ##STR1## in which R.sub.1, R.sub.2, R.sub.3, R.sub.4 and R.sub.5 are hydrogen, fluorine, chlorine or bromine atoms or C.sub.1 -C.sub.6 -alkyl, C.sub.1 -C.sub.6 -alkoxy, nitro, cyano, trifluoromethyl, aidehyde, C.sub.1 -C.sub.4 -alkoxycarbonyl, -SO.sub.2 -C.sub.1 -C.sub.4 -alkyl, -SO.sub.2 -phenyl, -CONH.sub.2, -CON(C.sub.1 -C.sub.4 -alkyl).sub.2, hydroxy, carboxy, -NH.sub.2 or -N(C.sub.1 -C.sub.4 - alkyl).sub.2 groups, at least one of the substituents R.sub.1 -R.sub.5 being one of said halogen atoms, which comprises reacting 1 mol of a benzophenone, asymmetrically substituted on the benzene rings A and B, of general formula (2): ##STR2## in which R.sup.1 -R.sup.10 are as defined above for R.sub.1 -R.sub.5, with about 1 to about 10 mol of an oxidizing agent selected from the group comprising hydrogen peroxide, urea/hydrogen peroxide addition product, an alkali metal peroxide, ammonium, alkali metal or alkaline earth metal peroxodisulfates, pertungstates, perborates or percarbonates, ozone, alkyl- or aryl-percarboxylic acids, alkyl- or aryl-persulfonic acids or persulfuric acid, at temperatures from about -20.degree. to about +100.degree. C.
一种制备式(1)的卤代苯甲酸的方法:##STR1## 其中R1,R2,R3,R4和R5是氢,氟,氯或溴原子或C1-C6烷基,C1-C6烷氧基,硝基,氰基,三氟甲基,醛,C1-C4烷氧羰基,-SO2-C1-C4烷基,-SO2-苯基,-CONH2,-CON(C1-C4烷基)2,羟基,羧基,-NH2或-N(C1-C4烷基)2基团,其中至少一个取代基R1-R5是上述卤原子之一,其包括将一摩尔的对苯二酮与一至十摩尔的氧化剂反应而制备。所述对苯二酮在苯环A和B上不对称取代,其通式为(2):##STR2## 在温度从-20℃到+100℃之间,所述氧化剂选自包括过氧化氢,脲/过氧化氢加成物,碱金属过氧化物,铵,碱金属或碱土金属过二硫酸盐,高钨酸盐,过硼酸盐或过碳酸盐,臭氧,烷基或芳基过碳酸酯,烷基或芳基过磺酸或过硫酸,反应制备。