The utilization of synthesis gas for the deoxygenation of cyclohexanone over alumina-supported catalysts: Screening catalysts

Environmental regulations motivate the industries to replace conventional fuels and chemicals by those produced from biomass. In this regard, hydrodeoxygenation of lignin compounds is of a great deal of attention. Synthesis gas could be utilized instead of pure hydrogen for the cleavage of oxygen-containing chemical bonds through hydrodeoxygenation. Following this, the utilization of synthesis gas is investigated in the present contribution. A wide range of commercial alumina-supported catalysts is investigated. The experimental results of cyclohexanone hydrodeoxygenation in the presence of pure hydrogen and synthesis gas at 573 K and 20 bar of total pressure are presented and discussed. The whole investigated catalysts show good activity toward the hydrodeoxygenation of cyclohexanone. Methylatedbenzene derivatives are produced from cyclohexanone hydrodeoxygenation for the first time. The catalysts composed of platinum showed the best performance. By utilizing a chlorinated platinum catalyst, 89.6% cyclohexanone conversion, 100% total hydrocarbon selectivity, and 44.6% total hydrocarbon yield are obtained. In the case of syngas-assisted hydrodeoxygenation, 80.1% cyclohexanone conversion, 100% total hydrocarbon selectivity, and 29.6% total hydrocarbon yield are obtained by utilizing the same catalyst. The presence of methylated aromatics proves the accomplishment of methanation or direct aromatization reactions in the presence of carbon oxides and hydrogen.