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Gas phase oxidation; vanadium containing solid core mesoporous silica shell; diphenylmethane.

A novel vanadium containing solid core mesoporous silica shell catalyst was synthesized with different Si/V ratios by sol-gel method under neutral conditions. The synthesized materials were characterized by various techniques and gas phase diphenyl methane oxidation reaction. The mesoporosity combined with microporosity are formed by incorporation of octadecyltrichloro silane and triethylamine in the catalyst and it was found out from E-DAX and BET—surface area analysis. The material was found to be nanocrystalline. Vanadium is present as V⁴⁺ species in as-synthesized samples and convert to V$^{5+}$ on calcination. Most of the vanadium is present in tetrahedral or square pyramidal environment. Incorporation of vanadium in silica framework was confirmed by ²⁹Si MAS NMR analysis. Among the various vanadium containing solid core mesoporous silica shell catalysts, the Si/V =100 ratio exhibited maximum efficiency towards diphenyl methane to benzophenone gas phase reaction. The optimum condition required for maximum conversion and selectivity was found out from the catalytic studies.

N Venkatathri¹ Vijayamohanan K Pillai² A Rajini¹ M Nooka Raju¹ I A K Reddy¹

1. Department of Chemistry, National Institute of Technology, Warangal 506 004, India
2. Physical and Materials Chemistry Division, National Chemical Laboratory, Pune 411 008, India

Published

January 2013

Manuscript received

24 February 2012

Manuscript revised

26 June 2012

Accepted

10 July 2012