申请人:——
公开号:US20020035175A1
公开(公告)日:2002-03-21
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。