Defense Date

1983

Document Type

Thesis

Degree Name

Master of Science

Department

Chemistry

First Advisor

Dr. Gordon A. Melson

Abstract

Some bifunctional ZSM-5 supported ruthenium catalysts (Ru/ ZSM-5) were prepared by an extraction technique employing Ru 3(C0)12 • The weight percentage Ru ranged from approximately 1% to 8% Ru as determined by Atomic Absorption Spectroscopy. Characterization data employing Infrared (IR) Spectroscopy, X-ray Powder Diffractometry (XRPD), X-ray Photoelectron Spectroscopy (XPS/ESCA), Ion-Scattering Spectrometry (ISS) and Chemisorption were obtained for the catalysts. The data indicated the presence of highly dispersed Ruo2 particles of less than 60 A on the surface of the as-prepared (AP) catalysts. Calcination of the AP catalysts at 500°C for 24 h increased the particle size of the Ruo2 species. Characterization of the Ru/ZSM-5 Used catalyst with the highest Ru loading indicated the presence of Ru 0 and Ruo2 species suggesting that reduction of this AP catalyst was incomplete.

The AP catalysts were evaluated for their ability to convert synthesis gas to hydrocarbon products. A 1:1 H2:CO synthesis gas mixture was used in a continuous flow microreactor from 260°C to 320°C. Gas chromatography was employed for analysis of the gaseous effluent. The oil fraction (C5-C 11 hydrocarbons) was analyzed by Fluorescent Indicator Adsorption (FIA) Chromatography. At 300°C, the oil fraction obtained from the 0.98% Ru/ZSM-5 catalyst was composed of 71% aromatics, 4% olefins and 25% saturates . The catalytic data obtained for the 2.88% and 7.32% Ru/ZSM-5 catalysts are similar; it is concluded that there is no increase in the number of active metal sites for the conversion of synthesis gas due to layering of the Ru species in the 7.32% Ru/ZSM-5 catalyst. Furthermore, the two higher loadings of Ru did not cause the production of high yields of aromatics as obtained from the 0.98% Ru/ZSM-5 catalyst. This may be due to blockage of the acid sites in the ZSM-5 support which are known to catalyze the production of aromatics.

It was concluded that the AP catalysts contained highly dispersed small particles of Ru02 on the zeolite surface and agglomeration occurs when the catalysts are calcineff in air. Also, the AP catalysts were found to be active for the Fischer-Tropsch reaction. The oil produced by using these catalysts has a high aromatic content. Correlations between the catalyst structure and activity for the conversion of synthesis gas have been drawn.

Rights

© The Author

Is Part Of

VCU University Archives

Is Part Of

VCU Theses and Dissertations

Date of Submission

8-7-2015

Included in

Chemistry Commons

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