The Malaysian Journal of Analytical Sciences Vol 11 No 1 (2007): 117 – 123

 

 

BIFUNCTIONAL Nb/Ti-MCM-41 CATALYST IN OXIDATIVE ACIDIC REACTION OF CYCLOHEXENE TO DIOL

 

Zainab Ramli, Mazidah Abdul Shukor and Didik Prasetyoko

 

Dept. of Chemistry, Faculty of Science, Universiti Teknologi Malaysia,

81310 UTM Skudai, Johor D.T.

 

Abstract

Bifunctional oxidative and acidic catalyst was prepared by incorporating titanium ion (Ti⁴⁺) and niobic acid in mesoporous molecular sieves MCM-41 structure. The catalyst is active both in oxidation, and acid-catalyzed reaction of olefin to diol. Nb/Ti-MCM-41 catalyst was prepared by first synthesizing Ti-MCM-41 by hydrothermal method, followed by  subsequent impregnation of niobic acid (Nb) into Ti-MCM-41 at various %wt Nb loading. The framework structure of Ti-MCM-41 collapsed after incorporation of Nb but  the tetrahedral form of Ti⁴⁺  still  maintained with  octahedral Nb  species . Both Brønsted  and  Lewis  acid  sites  are  present  in  all  Nb/Ti-MCM-41 samples.   The formation of  cyclohexanediol in the epoxidation of cyclohexene proved the bifunctional  oxidative and  acidic catalyst through the formation of cyclohexane oxide. The yield increased with the increase amount of the Brønsted acid sites provided by niobium species .

 

Keywords: bifunctional catalyst, Nb/TiMCM-41, oxidative-acidic, diol

 

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