Holzforschung, Vol. 65, pp. 439–451, 2011 • Copyright  by Walter de Gruyter • Berlin • Boston. DOI 10.1515/HF.2011.081 2010/219 Article in press - uncorrected proof Review Bio based fuels and fuel additives from lignocellulose feedstock via the production of levulinic acid and furfural 11 th EWLP, Hamburg, Germany, August 16–19, 2010 Geertje Dautzenberg 1 , Mirko Gerhardt 2 and Birgit Kamm 2, * 1 biorefinery.de GmbH, Stiftstraße 2, D-14471 Potsdam, Germany 2 Research Institute Bioactive Polymer Systems e.V., Kantstraße 55, D-14513 Teltow, Germany *Corresponding author. Research Institute Bioactive Polymer Systems e.V., Kantstraße 55, D-14513 Teltow, and Brandenburg University of Technology Cottbus, Germany E-mail: kamm@biopos.de Abstract The demand for biomass-derived fuels and fuel additives, particularly in the transportation sector, has stimulated intense research efforts in the chemistry of levulinic acid and levulinic acid secondary products over the past decade. Addi- tionally, recent technological progress in lignocellulosic feed- stock (LCF) chemistry has also increased attention in this regard. As a result, several oxygenating fuel additives with potential applications in both gasoline and diesel fuels have been identified. Some of the chemicals, such as ethyl val- erate, appear to be viable alternatives to the currently used branched, short-chain ethers that are derived from side prod- ucts of petrol refining. Cost-effective applications of ligno- cellulosic biomass are a crucial aspect of its feasibility. In consideration of the LCF biorefinery concept, the feasibility must also include the chemical pulping of LCF and the com- prehensive utilisation of its main constituents cellulose, hemi- celluloses, and lignin. The present study focuses on cellulose and hemicelluloses as viable sources for the production of biofuels and biofuel additives. Multifunctional catalysis, including hydrogenation and acid catalysis are the primary instruments used for the conversion of the monomeric car- bohydrate building blocks, i.e., mainly C5 sugars, such as xylose and arabinose, and C6 sugars in the form of glucose and their respective secondary products, furfural and levuli- nic acid. Lignin utilisation is not addressed in this paper. Keywords: biofuel; furfural; LCF biorefinery; levulinic acid; levulinic acid esters; lignocellulosic feedstock (LCF); 2- methyl tetrahydrofuran; pentenoic acid esters; valeric acid esters; valerolactone; g-valerolactone. Introduction Due to the finite nature of fossil fuels and the unbalanced CO 2 equilibrium that is caused by the extensive use of the former, the public increasingly asks for a substitution of fos- sil-based transportation fuels and fuel additives by bio-based substances, specifically in industrialised countries. Conse- quently, governmental directives in both the U.S. and Europe demand the gradual integration of current fossil fuels with biomass-derived fuels. The production of biomass-derived fuels, such as fatty acid methyl esters (FAME), catalytically hydrogenated fatty acids (NExBTL) from plant oils, and eth- anol from corn, is in competition with raw material use for human nutrition. Thus, a balanced and sustainable utilization of biomass is searched for. In theory, all fuels could be produced from syngas, which can be obtained from coal, but also from lignocellulose-rich biomass (wood, straw), by Fischer-Tropsch synthesis (FTS). Currently, synthetic diesel production facilities exist in South Africa (Sasol), in Malaysia (Shell), and in other remote loca- tions (Huber et al. 2006). Research on syngas and FTS focuses on the production of higher waxes, which can be cracked under hydrogenating conditions into hydrocarbons of desired chain length. Such a pilot plant that uses syngas derived from wood was operated in collaboration between Shell and the Energy Research Centre of the Netherlands (ECN), and produced a sulphur-free diesel fuel. Boerrigter (2002) reported that yields of 210 l per ton biomass should be reached by further improving the implied technology. The main drawback of the process is its low thermal efficiency, in which the maximum was estimated to be 46.2%, in com- parison to 75% with biomass gasification (Huber et al. 2006). Whether syngas production from biomass, specifically from lignin-rich biomass that can be regarded as young coal (Gerhardt et al. 2010), and successive FTS will be a viable route for fuel production, depends on the development of further alternatives in the conversion of lignocellulose-rich feedstock. Short-branched alkylethers, such as methyl tert-butyl ether (MTBE), ethyl tert-butyl ether (ETBE), and tert-amyl methyl ether (TAME), are used by the fuel industry primarily because they are produced from broadly available, low molecular weight by-products of petrol refining (isobutene, isoamylene, and dipropylene). These alkylethers offer ben- efits in the combustion quality and octane number of gaso- line. Based on this experience, currently, attention is paid to the synthesis of hydrocarbon oxygen heterogens of relative low polarity from lignocellulosic feedstock (LCF). Efforts are centred specifically on levulinic acid, because of its chemical versatility. In fact, it has also been identified as one of the 12 potential platform chemicals in the biorefinery con- cept. The probability of its large-scale production directly from cellulosic biomass has increased significantly as a result Brought to you by | Simon Fraser University Authenticated Download Date | 5/30/15 10:19 AM