Review

Lignin has a potencial to become a significant renewable resource for the direct production of aromatic hydrocarbons and phenols from biomass. To achieve this goal, lignin has to be selectively extracted from the lignocellulosic biomass and selectively depolymerized. The goal of this chapter is to discuss the possibilities of wider utilization of lignin as a chemical raw material. Hence, the chapter is divided into three main parts. In the first one, lignin, its composition main characteristics and current production and use are briefly introduced (section 1 and 2). The second part (section 3) deals with primary upgrading of lignin mainly by its pyrolysis which is crucial for the selection of catalysis being used in the secondary upgrading. The third part (section 4) puts an emphasis on the applications of heterogenous catalysts affording the production of valuable chemical intermediates. Different examples based on the upgrading strategy (pyrolysis, catalytic cracking, hydrotreating and their combinations) are provided using both real feedstocks and model compounds to reveal the complexity of these approaches as well as the underlying mechanisms.