Catalytic Process Development of Bio-BTX from Lignocellulose Derived Product: Preliminary Study Using Transition Metal Catalysts

Abstract

Lately, the increase in biofuel production has simultaneously led to lignocellulose material disposal activities. As a waste produced by the biofuel industry, lignocellulose materials are not utilized fully yet due to their complex polymeric structure. As one compound of lignocellulose, lignin possesses the lowest economic value due to its recalcitrant nature. In this work, guaiacol as one of monomeric substance originated from lignin is used as a representative molecule to be valorized due to the existence of both hydroxyl and methoxy moiety groups in it. One important reaction of lignin monomeric substance (phenolic compounds) valorization is oxygen removal. Aromatic substances such as Benzene and Toluene are produced through oxygen removal from the guaiacol molecule. Hydrodeoxygenation of guaiacol is aimed to remove oxygen atoms from it. Though conventionally hydrogen for the Hydrodeoxygenation process is supplied by external molecular hydrogen, in this work it is supplied from hydrogen atom abstraction of methylcyclohexane. Therefore, in a one-pot catalytic reaction system, methylcyclohexane dehydrogenation is the sole hydrogen provider for subsequent hydrodeoxygenation of guaiacol and this novel concept of a circular hydrogen economy has been proven its feasibility through heterogeneous catalytic reaction schemes conducted in this work. Metal supported on zeolite beta is selected as heterogeneous catalysts to evaluate the feasibility of one-pot hydrodeoxygenation and dehydrogenation reaction. Of every catalytic reaction attempt, multiple products consist of alkylated phenol, phenol itself, and toluene are observed proofing the feasibility of this concept. Possible interaction of catalyst surface acidity and metal contents are also probed through the distribution of byproducts. Overall, sequential dehydrogenation and hydrodeoxygenation have been proven through a catalytic reaction catalyzed by metal-supported zeolite beta catalyst and this work can potentially pave the way for further application.