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2 Polish Journal of Chemistry

2 2000

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Physico-Chemical Characteristic of Sulfated Mixed Oxides of Sn with Some Rare Earth Elements

Jyothi T., Sreekumar K., Talawar M., Mirajkar S., Rao B., Sugunan S.

Polish Journal of Chemistry

2000

Vol. 74, nr 6

801-812

A series of binary mixed oxides of tin with three rare earth elements viz. La, Ce and Sm were prepared by co-precipitation method and sulfate treatment was performed by treating the mixed hydroxides with sulfuric acid or ammonium sulfate. The physicochemical characterization has been done by XRD, BET-S.A., SEM, EDX, TG-DTA and IR spectroscopy. Adsorption of n-butylamine was used to probe the acidic properties of the catalysts. The strength and distribution of acid sites depend on the mixed metal oxide composition, as well as on the preparation method. The rare earth modified sulfated tin oxide catalysts are more active in the oxidative dehydrogenation of cyclohexanol and cyclohexane, compared to the corresponding mixed oxide systems and sulfated tin oxide. Among the different sulfated oxide systems investigated , cerium prooted catalysts displayed a better selectivity towards dehydrogenation products.

Oxidative Dehydrogenation of Ethylbenzene over Zn1-xNixFe2O4 (x=0,0.2, 0.5, 0.8 and 1.0) Type Systems : Effect of Composition on Surface Properties and Catalytic Activities

Sreekumar K., Thomas M., Jyothi T., Biju M., Sugunan S., Rao B.

Polish Journal of Chemistry

2000

Vol. 74, nr 4

509-517

The activity and selectivity of this reaction were correlated well with the surface acid-base and redox properties the catalyst. Basicity of the systems was studied based on the adsorption studies using electron acceptors with different electron affinity values. The surface acidity of the system was evaluated using cyclohexanol decomposition studies.