Studies on characterization and catalytic properties of oxides and zeolites

Abstract

Chapter 1 : INTRODUCTION This chapter starts with a listing of the objectives of the study, namely, evaluation of activity of a few catalysts based on synthetic zeolites and supported metals towards conversion of ethanol and hydrogenation of phenol. A brief review of the methods of preparation, structure-analysis and activity-characterization of the zeolites has also been presented. The physical methods used for characterization of zeolites, viz. sorption-technique, XRD, IRS, NMR, TPD, TG-DTA, etc., have been briefly described by taking examples from existing literature. The shape-selective properties of the zeolites with particular reference to molecular traffic control, diffusion and deactivation have been evaluated with respect to important industrial processes. A literature review has been done with particular reference to the use of HZSM-5 zeolites for conversion of methanol and ethanol to various products. The chapter concludes with a description of supported metal catalysts with alumina and zeolites as the supports. Importance of platinum and palladium supported catalysts in a few industrial processes, more particular in hydrogenation of phenol, has been reviewed. The role of SMSI and other types of interactions in catalysis by supported metals has also been pointed out. [ 3 figures, 2 tables, 203 references, 56 pages] Chapter 2 : CONVERSION OF ETHANOL TO HYDROCARBONS Two HZSM-5 zeolites were prepared with silica-alumina ratios of 40 and 206. The zeolites were characterized with XRD, IRS, surface area and particle size measurement, and chemicalanalysis. Six different catalysts with composition 20% HZSM-5 (206), 80% AL2O3; 40% HZSM-5 (206), 60% AL2O3; 80% HZSM-5 (206), 20% AL2O3; 100% HZSM-5 (206); 100% HZSM-5 (40) and 100% AL2O3 were used in studying the ethanol conversion reaction in a fixed bed, continuous flow reactor. Detailed experimental set-up has been described. The feeds used were 20%, 50%, 80%, and 100% ethanol. The reaction was studied in the temperature and pressure ranges of 673-773K and 0.1-3