Thermochemical Valorization of Lignin

Abstract The inevitability of transition toward a biobased economy is fueled by the problems related to fossil fuel utilization such as climate change due to greenhouse gas emissions. Lignin is a renewable feedstock that can be used to produce hydrocarbons in a sustainable manner. Lignin is obtained as a by-product of several conversion processes when it is isolated from the lignocellulosic biomass matrix. It is the major fraction that contributes to the organic hydrocarbons such as aromatics, phenolics, and platform chemicals that are presently produced from fossil resources. Lignin exhibits different physicochemical characteristics depending on the isolation process used. Lignin, over the years, has been converted to various value-added hydrocarbons (bioenergy, biofuels, biochemicals, and petrochemical feedstocks) using several thermochemical methods of conversion such as pyrolysis, gasification, and liquefaction. Challenges in the valorization of lignin include understanding the effect of source on the lignin structure, development of novel catalysts for conversion, increased selectivity and yield from processes, and effective separation processes.