Solvent-phase thermal cracking of lignin for production of potential liquid fuels

Lignin is the least utilized biomass component. Unlike the ones from pulping process, the lignins generated from the biomass conversion process are relatively clean, free of sulfur or sodium. It is a feedstock very much amenable for further conversion. The primary goal of this research is to broaden the existing data base pertaining to this concept. This study has limited the conversion methodology to non-catalytic thermal cracking in solvent phase without supplementation of hydrogen or hydrogen donor solvent. Two different solvents were employed : acetone and butanol. Although these solvents arc miscible with water, they were used as water-free basis. The cracking experiments have been done in externally agitated tubing bomb reactors placed inside a sand-bath. The reaction temperatures were ranged 250 similar to 450 degrees C. The overall conversion was determined by the weight of residual solid. The liquid products were analyzed by GC/MS. The overall conversion generally increased with reaction temperature up to 400 degrees C then leveled off thereafter. The highest conversions were observed in the vicinity of 60% for both acetone and butanol cracking. In the case of cracking in acetone phase, hydrocarbons as well as oxygenates were found. The identified primary products included branched alkene (dimethyhexene), aromatics (trimethyl benzene), side-chain oxychemicals (methylpentanone trimethylcyclohexanone), ketones (methyl-isobutyl ketone), and phenolics (methyl, ethylphenol). The products from butanol phase cracking included: esters (methyl-propyl, butylesters), ethers (N-butyl, isobutylethers), and phenolics (methoxy, di-butoxy phenols).