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The role of Ti and lewis acidity in manganese oxide octahedral molecular sieves impregnated with titanium in oxidation reactions

Fitri, Hayati and Chandren, Sheela and Hamdan, Halimaton and Hadi, Nur (2014) The role of Ti and lewis acidity in manganese oxide octahedral molecular sieves impregnated with titanium in oxidation reactions. Bulletin of Chemical Reaction Engineering and Catalysis, 9 (1). pp. 28-38. ISSN 1978-2993

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Official URL: http://dx.doi.org/10.9767/bcrec.9.1.5603.28-38

Abstract

Octahedral manganese oxide molecular sieves (OMS-2) was prepared by precipitation method and modified by impregnation of titanium with different titanium/manganese (Ti/Mn) ratio. It was discov-ered that Ti/Mn ratio of less than 0.5 still retains the original pure cryptomelane structure of OMS-2. However, for sample with Ti/Mn ratio of more than 0.5, some rutile phases of titania (TiO2) can be de-tected together with the cryptomelane phase. Lewis acid sites were also observed in the titanium modi-fied OMS-2 (Ti-OMS-2). Ti-OMS-2 was then used as catalysts for the oxidation of cyclohexane, cyclo-hexene and styrene, where Ti-OMS-2 with Ti/Mn ratio of 0.67 was most active in all three of the oxida-tion reactions as compared to TiO2 and OMS-2. The results suggest that both titanium sites in frame-work and non-framework and the Lewis acidity created by the impregnation of Ti, increased the activi-ty of OMS-2 in oxidation reactions.

Item Type:Article
Uncontrolled Keywords:oxide, molecular sieves
Subjects:Q Science
Divisions:Science
ID Code:63019
Deposited By: Siti Nor Hashidah Zakaria
Deposited On:06 Jun 2017 14:44
Last Modified:06 Jun 2017 14:44

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