Kinetic and Reaction Network Determination of Upgrading Process of Lignin-Derived Bio-Oil in the Presence of Hydrogen

In this research, upgrading of cyclohexanone as a representative of lignin-derived bio-oil via hydrotreating process catalyzed by Pt/γ-Al2O3 in a fixed-bed tubular reactor is investigated at 573-673 K, 14 bar and space velocity of 3–120 (g of cyclohexanone)/(g of catalyst × h). In order to determine the reaction network and kinetic, the cyclohexanone conversion and products selectivity are evaluated. Data collected at the low conversion of cyclohexanone which quantitatively represents initial product distribution consists of hydrogenation, hydrodeoxygenation, dehydration, and condensation. The highest apparent activation energy is related to the condensation reaction in which the dehydration reaction resulting in phenol formation is assumed to be 17 kJ/mol. Rate constants of formation for the main products decrease as follows: phenol >  2-cyclohexylidenecyclohexan-1-one > 2-methylphenol > cyclohexylbenzene > cyclohexane > biphenyl > 2-cyclohexen-1-one > 2-cyclohexylcyclohexan-1-one > 2-phenylphenol > cyclohexene > 2-cyclohexylphenol.