Liquid fuels from biomass: catalysts and reaction conditions

Abstract

The use of ..cap alpha..-phellandrene as a hydrogen transfer agent in wood liquefaction was studied at 200/sup 0/C. No significant thermally promoted hydrogen transfer occurred under these conditions. Dilute sulfuric acid was added to test the possibility of hydride transfer from ..cap alpha..-phellandrene to wood. Extensive solvent alkylation of the wood occurred in the presence of up to 2 wt % of sulfuric acid. Addition of palladium as a hydrogenation catalyst resulted in lower overall conversion based on the toluene-insoluble residue obtained, and in lowered levels of solvent alkylation. Several inorganic salts were tested as catalytic additives for wood liquefaction at 250/sup 0/C in the presence of tetralin as a possible hydrogen donor. No hydrogen transfer from the solvent was observed. About 50% by weight of the wood was converted to gases and toluene and water extractable materials in the absence of an additive. Of the additives tested, nickel chloride, sodium carbonate, and ferric chloride resulted in wood conversions greater than or equal to those obtained in the absence of an additive. Toluene extraction was used as a measure of oil yield. Of the additives tested, ferric chloride resulted in the highest yield of toluene solubles with about 28 wtmore » % of the wood being converted to oil. Atomic H/C ratios of the toluene extracts ranged from 1.51 to 0.85 compared to 1.21 for untreated wood. The O/C ratios of the toluene extracts ranged from 0.18 to 0.44 compared to an O/C ratio of 0.57 for untreated wood. Nuclear magnetic resonance spectroscopy indicated that the toluene soluble fraction of the products contained benzylic, phenolic, and alcoholic protons. Ultraviolet spectra indicated the presence of carbonylic and aldehydic groups.« less