Gas phase Beckmann rearrangement of cyclohexanone oxime to ε-caprolactam over mesoporous, microporous and amorphous Nb2O5/silica catalysts: A comparative study

被引：39

作者：

Anilkumar, M. ^{[1
]}

Hoelderich, W. F. ^{[1
]}

机构：

[1] Rhein Westfal TH Aachen, Dept Chem Technol & Heterogeneous Catalysis, D-52074 Aachen, Germany

来源：

CATALYSIS TODAY | 2012年 / 198卷 / 01期

关键词：

Nb2O5/SiO2; Mesoporous materials (M41S structure); Microporous material (Beta zeolite); Gas phase Beckmann rearrangement reaction; Cyclohexanone oxime; Caprolactam; NIOBIUM OXIDE CATALYSTS; SILICATE MOLECULAR-SIEVES; CONTAINING MCM-41; INFRARED-SPECTROSCOPY; ACIDIC PROPERTIES; SBA-15; MATERIALS; BETA-ZEOLITE; FT-IR; EPOXIDATION; TRIBLOCK;

D O I：

10.1016/j.cattod.2012.01.043

中图分类号：

O69 [应用化学];

学科分类号：

081704 ;

摘要：

The gas phase Beckmann rearrangement of cyclohexanone oxime to epsilon-caprolactam was investigated over niobium containing mesoporous (Nb-MCM-41, Nb-HMS and Nb-SBA-15), microporous (Nb-Beta zeolite) and amorphous (Nb impregnated on SiO2) catalysts. A relation between catalytic activities, structural and the acidic properties was derived. The catalysts Nb2O5/SiO2, Nb-MCM-41, Nb-SBA-15, and Nb-HMS resulted in higher cyclohexanone oxime conversion and caprolactam selectivity compared with Nb-Beta zeolite. Almost 100% cyclohexanone oxime conversion and up to 98% caprolactam selectivity were achieved over Nb2O5/SiO2 catalyst. Further, the catalytic activity results of Nb-MCM-41 are fairly similar to Nb2O5/SiO2. The high activity of both catalysts is related to vicinal silanol groups and silanol nests with weak acidity and negligible Bronsted acid sites. The physico-chemical properties of the investigated catalysts were characterized by various techniques including X-ray diffraction, N-2 physisorption, Fourier transform infrared spectroscopy (FTIR), UV-vis diffuse reflectance, atomic emission spectroscopy (ICP-AES), and Raman spectroscopy. Catalyst acidity was measured by NH3-TPD and pyridine adsorbed FTIR spectroscopy. The structural characterization results revealed that Nb was incorporated into the mesoporous and microporous materials framework. (C) 2012 Elsevier B.V. All rights reserved.

引用

页码：289 / 299

页数：11

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