The invention includes a process for converting biomass into C.sub.7-C.sub.10 alkylbenzenes useful as blending components for petroleum or petroleum derived fuels. The process includes a base catalyzed depolymerization of lignin within the biomass, followed by hydroprocessing of the depolymerized lignin to C.sub.7-C.sub.10 alkylbenzenes. The C.sub.7-C.sub.10 alkylbenzenes are useful for enhancing the octane level of petroleum or petroleum-derived fuels, such as gasoline. In addition, the C.sub.7-C.sub.10 alkylbenzenes are useful as intermediates in the production of numerous organic chemicals.
 The United States Government has rights in this invention under Contract No. DE-AC36-99GO10337 between the United States Department of Energy and the National Renewable Energy Laboratory, a Division of the Midwest Research Institute.