Catalytic Hydrodesulfurization of Thiophene: Vi. Comparisons Over Molybdenum Disulfide, Cobalt Molybdate, and Chromia Catalysts

The hydrodesulfurization of thiophene over five molybdenum disulfide catalysts, an alumina-supported cobalt molybdate, and a chromia catalyst has been investigated. Comparisons on the basis of equal surface areas showed that desulfurization activity did not vary a great deal. It was established mainly by working at very low conversion levels that 1,3-butadiene was a product over all these catalysts, and that a mixture of butadiene, the three n-butenes, and n-butane constituted the actual primary reaction product. The reaction rate is strongly dependent on conversion, probably as the result of small quantities of product H2S, the rate decreasing by a factor of 100 in going from 0.01% to 5% conversion in a typical flow experiment. A strong enhancement of the rate over MoS2 was noted in the presence of oxygen.