Sustainable biofuel production via catalytic hydrodeoxygenation of 4-methylanisole over Mo/nano γ-Al2O3

Abstract

Recently, valorization of lignin biomass derived pyrolysis bio-oil for production of a sustainable fuel has turned to be a vital concern. Hydrodeoxygenation (HDO) has turned to be the most suitable developing process for production of a fuel with high heating value. In the current study, the HDO of 4-methylanisole as a model compound of pyrolysis oil, is investigated over Mo/nano γ-Al2O3 catalyst at a wide range of operating conditions. 4-methylanisole mainly follows hydrogenolysis and direct HDO to produce 4-methylphenol and toluene, respectively. Increasing operating temperature (623–773 K) and inverse weight hourly space velocity (WHSV−1: 0.008–0.333 g cat× h/g 4-methylanisole) lead in promoting toluene production. However, 4-methylphenol production and alkylation reactions are favored at high pressures (12–20 bar). 4-methylanisole conversion through HDO is 98% at 12 bar, 623 K and WHSV−1 of 0.333 g cat× h/g 4-methylanisole. The selectivity of toluene and 4-methylphenol production at the mentioned conditions is 0.44 and 0.17, respectively. It is inferred that hydrogenation, hydrogenolysis of Caliphatic—O, dehydration, deoxygenation of Caromatic—O, alkylation and tautomerization are the main reaction pathways during upgrading process which influence the selectivity of the products.