Provided is a process for preparing 2H-benzotriazole UV absorbers containing a perfluoroalkyl moiety at the 5-position of the benzo ring, for example a trifluoromethyl group, which involves diazotizing the perfluoroalkyl substituted o-nitroaniline using concentrated sulfuric acid plus sodium nitrite or nitrosylsulfuric acid to form the corresponding monoazobenzene intermediate via the diazonium salt intermediate which is reduced to the corresponding 5-perfluoroalkyl substituted 2H-benzotriazole UV absorber compound by conventional reduction means. Also provided is a novel one-pot, multiphase reaction for the preparation of 2(2-nitrophenylazo) substituted phenols, which are precursors for 2H-benzotriazole UV absorbers.
提供了一种制备含有苯环5位的
全氟烷基(例如三
氟甲基)的2H-苯并三唑
紫外线吸收剂的方法,其中使用浓
硫酸加
亚硝酸钠或
亚硝基硫酸制取
全氟烷基取代的邻
硝基苯胺的重
氮化物中间体,通过还原手段将中间体还原为相应的5-
全氟烷基取代的2H-苯并三唑
紫外线吸收剂化合物。还提供了一种新型的一锅法多相反应,用于制备2(2-
硝基苯偶氮)取代
酚,其是2H-苯并三唑
紫外线吸收剂的前体。