Selective hydrodeoxygenation of guaiacol to phenolics over activated carbon supported molybdenum catalysts

Activated carbon-supported molybdenum dioxide catalyst and molybdenum carbide catalyst were prepared by reduction in hydrogen with different temperatures. Hydrodeoxygenation (HDO) of guaiacol was investigated in 3 MPa initial H-2 pressure with these two catalysts. Phenolics were detected as the main products when catalyzed by molybdenum dioxide catalyst. Through analyzing the HDO selectivity of guaiacol and the intermediates including 1,2-dihydroxy-3-methylbenzene, catechol, phenol and anisole, the HDO reaction pathways of guaiacol over Mo-based catalysts were proposed. In the first stage, transalkylation and breaking of three C-O bonds take place to produce 1,2-dihydroxy-3-methylbenzene, catechol, phenol and anisole, whereafter cresol, phenol, toluene and benzene are produced. Furthermore, the effects of reaction temperatures and solvents on HDO of guaiacol were investigated. Using tetralin as solvent, in 3 MPa initial H-2 pressure and at 573 K, the conversion of guaiacol reached 98% with phenolics as the major product and the selectivity was greater than 91% after three hours of reaction time. (C) 2017 Elsevier B.V. All rights reserved.