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.
提供的是一种制备在苯环的5-位上含有
全氟烷基的2H-苯并三唑UV吸收剂的过程,例如三
氟甲基基团,其中涉及使用浓
硫酸加
亚硝酸钠或
亚硝基硫酸盐使
全氟烷基取代的o-
硝基苯胺重氮化,以形成相应的单
偶氮苯中间体,该中间体通过惯常还原手段还原为相应的5-
全氟烷基取代的2H-苯并三唑UV吸收剂化合物。同时提供了一种新型的一锅法、多相反应,用于制备2(2-
硝基苯基偶氮基)取代
酚,这些化合物是2H-苯并三唑UV吸收剂的前体。