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Indexed by:期刊论文

Date of Publication:2013-06-01

Journal:MICROPOROUS AND MESOPOROUS MATERIALS

Included Journals:SCIE、EI

Volume:173

Page Number:129-138

ISSN No.:1387-1811

Key Words:Zeolite beta; Si/Al ratio; Mesoporosity; Alkaline treatment; Acid catalytic performance

Abstract:Small crystal zeolites beta with molar Si/Al ratios of 21,30 and 40.5 were successfully obtained by treating parent beta (Si/Al = 14.5) with different oxalic acid concentrations. The influence of Si/Al ratio of zeolite beta on effective mesopore formation via NaOH treatment was studied by investigating the changes in crystallinity, morphology, chemical composition, acidity and textural property of zeolite beta before and after alkaline treatment. The catalytic performance was evaluated in terms of alpha-pinene isomerization and benzoylation of naphthalene with benzoyl chloride. Substantial mesoporosity could be developed for zeolites beta with molar Si/Al ratios of 14.5-30, coupled with better preserved microporosity. Though the largest mesopore surface area (488 m(2) g(-1)) was achieved when Si/Al = 30, the crystallinity of zeolite beta was partly destroyed. The substantially improved catalytic activity of alkaline treated samples in alpha-pinene isomerization is mainly attributed to the developed mesoporosity, but the volcano curve change in catalytic activities of alkaline treated samples in benzoylation of naphthalene manifested that both mesoporosity and acid property play important role in a medium strong acid catalyzed reaction. (c) 2013 Elsevier Inc. All rights reserved.