PROCESSES FOR THE PREPARATION OF BENZOTRIAZOLE UV ABSORBERS
申请人:Ciba Specialty Chemicals Holding Inc.
公开号:EP1305298A2
公开(公告)日:2003-05-02
US6605727B2
申请人:——
公开号:US6605727B2
公开(公告)日:2003-08-12
US6566507B2
申请人:——
公开号:US6566507B2
公开(公告)日:2003-05-20
US6815550B2
申请人:——
公开号:US6815550B2
公开(公告)日:2004-11-09
[EN] PROCESSES FOR THE PREPARATION OF BENZOTRIAZOLE UV ABSORBERS<br/>[FR] PROCEDE DE PREPARATION D'ABSORBEURS D'UV BENZOTRIAZOLES
申请人:CIBA SC HOLDING AG
公开号:WO2002012202A2
公开(公告)日:2002-02-14
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.