PHYSICAL STUDIES OF CATALYSTS IN THE HETEROGENEOUS REACTIONS

Abstract

The aim of the present study is mainly directed to prepare iron oxide alumina catalysts and to study their activity and selectivity in a monolayer process of dehydration of 1 -hexanol and cyclohexanol using a flow technique and pulse technique under normal pressure .

Five types of iron oxide alumina catalysts were prepared which differ in their methods of preparation .The prepared catalysts were studied thermogravimetrically and spectro­ scopically before and after catalytic reaction beside studying their textural properties .

The kinetics of heterogeneous catalytic conversion of 1-hexanol and cyclohexanol was studied on the five iron oxide alumina catalysts at temperature range 280 to 380 °C using flow and pulse techniques . The activation energy and specific rate constants were calculated . Gaseous and liquid products were analyzed .The nature of the intermediate catalytic complex formed during catalytic action were also studied .

The results of this study showed that the method of preparation of the catalyst affects its activity and selectivity ,

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i.e. , catalysts prepared by coprecipitation and homogeneous solution method show highest activity twards the dehydration of cyclohexanol to cyclohexene than those prepared by impregnation and mechanical mixing methods . The results confirmed Balandin • s equation . Also the results confirmed that the conversion of 1-hexanol and cyclohexanol is a polymolecular catalytic process in which an intermediate of polymolecular catalytic complex is the rate determining step .