Vanillin production from lignin degradation using hydrothermal method over Fe2O3/Al2O3 catalysts

Abstract

Vanillin synthesis from lignin degradation using catalytic hydrothermal process over Fe₂O₃/Al₂O₃ catalyst was investigated. The Fe₂O₃/Al₂O₃ catalyst was prepared by wetness impregnation.  The prepared catalysts were characterized by using XRD and BET method. The lignin degradation reaction was carried out in a batch high-pressure reactor.  The effects of initial pressure, reaction temperature, and catalyst loading on vanillin yield were studied.  It was found that an increasing of temperature gave an increasing of vanillin yield.  However, the increasing of pressure and a number of catalyst loading showed the decrease of vanillin production due to the oxidation of produced vanillin to another product. The highest vanillin concentration of 8.54 mg/L was obtained at 160 ºC, 2 bars, and 0.5 g of the catalyst.