Please use this identifier to cite or link to this item: http://repositorio.unicamp.br/jspui/handle/REPOSIP/75603
Type: Artigo de periódico
Title: Silylation of [Nb]-MCM-41 as an efficient tool to improve epoxidation activity and selectivity
Author: Gallo, JMR
Pastore, HO
Schuchardt, U
Abstract: Well-ordered [Nb]-MCM-41 was synthesized at room temperature with essentially all niobium present in the sample substituted into the silica framework. The material was calcined and then silylated using hexamethyldisilazane (HMDS). Both calcined and silylated materials were characterized by X-ray diffraction (XRD), diffuse reflectance UV-vis, inductively coupled plasma emission (ICP-OES), infrared spectroscopy (FTIR), N-2 adsorption at low temperatures, thermogravimetry (TG), and nuclear magnetic resonance of Si-29 with magic-angle spinning (NMR-MAS). The materials were used as catalysts in the epoxidation of cis-cyclooctene with tert-butyl hydroperoxide (TBHP) and 70 wt% aqueous hydrogen peroxide as oxidants, to verify the influence of the silylation on the activity and selectivity. It was observed that the silylated material was more active for both oxidants, reaching 62% conversion and 94% selectivity after 48 h with TBHP and 13% conversion and 80% selectivity after 5 h with aqueous hydrogen peroxide. (c) 2006 Elsevier Inc. All rights reserved.
Subject: Nb-MCM-41
silylation
hexamethyldisilazane
epoxidation
cis-cyclooctene
Country: EUA
Editor: Academic Press Inc Elsevier Science
Rights: fechado
Identifier DOI: 10.1016/j.jcat.2006.07.002
Date Issue: 2006
Appears in Collections:Unicamp - Artigos e Outros Documentos

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