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.
提供了一种制备在苯环的5位含有
全氟烷基基团(例如三
氟甲基基团)的2H-苯并三唑紫外吸收剂的方法,该方法涉及使用浓
硫酸加
硝酸钠或
亚硝基硫酸制备
全氟烷基取代的邻
硝基苯胺,以形成相应的单氮偶
联苯中间体,通过传统还原手段将二氮盐中间体还原为相应的5-
全氟烷基取代的2H-苯并三唑紫外吸收剂化合物。还提供了一种用于制备2(2-
硝基苯基偶氮)取代
酚的新型一锅多相反应,这些化合物是2H-苯并三唑紫外吸收剂的前体。