关键词: ZSM-5分子筛, 固体酸催化剂, 苯基羟胺, Bambenger重排, 对氨基苯酚

Abstract:

Na-ZSM-5 was prepared by in-situ hydrothermal process. H-ZSM-5 (n(Si)/n(Al)=40) molecular sieves were prepared by ion exchange. p-Aminophenol was prepared by Bamberger rearrangement catalyzed by the molecular sieves using phenyl-hydroxylamine as raw material. XRD, FT-IR, N₂ adsorption-desorption, SEM and Py-FTIR techniques were used to study the topological structure, micropore pore size and acidity of Na-ZSM-5 and H-ZSM-5 molecular sieves. The results showed that the prepared molecular sieves had MFI microporous structures with well crystallinity. Py-FTIR technique showed that Na-ZSM-5 had almost no B acid. H-ZSM-5(40) molecular sieve had weaker B acid and L acid. Catalysis performance showed that phenyl-hydroxylamine conversion was low in the presence of ZSM-5 with weaker acidity as catalyst. However, because of its moderate pore size, p-aminophenol selectivity and yield reached as high as 72.48% and 58.75%, respectively. The optimal conditions of p-aminophenol preparation from phenyl-hydroxylamine Bamberger rearrangement were as follows: mass ratio 1∶3 of phenyl-hydroxylamine to H-ZSM-5(40) molecular sieve, optimal reaction temperature of 353 K, optimal reaction time of 2 h, and water as solvent. Phenyl-hydroxylamine conversion and p-aminophenol selectivity were as high as 86.35% and 78.33%, respectively.

Key words: ZSM-5 molecular sieve, Solid acid catalyst, Phenyl-hydroxylamine, Bambenger rearrangement, p-Aminophenol