Selective Extraction of Coniferyl Alcohol and Sinapyl Alcohol from Woody Lignocellulose

Abstract

Lignin is a renewable aromatic polymer that can produce fine chemicals. However, owing to the complex chemical structure of lignin, derivation and deep cracking of depolymerized monomers, the depolymerization and utilization of lignin generally suffer the problems such as complex products. Selective breaking of lignin bond is of certain significance to improve product selectivity and realize the graded utilization of lignin. In an organic solvent/water lignin extraction system, the ester bond in original lignin was selectively cracked to extract coniferyl alcohol and sinapyl alcohol without the addition of catalyst. The results showed that ethanol effectively breaks phenylethyl cinnamate and phenylacetate bond model compounds under mild conditions but shows no effect on the β-O-4 ether bond of phenoxy ethylbenzene. When poplar powder is used as substrate, the total yield of coniferyl alcohol and sinapyl alcohol is up to 57.57 mg/g, and the selectivity is 62.88% in dioxane/water 9∶1 solvent system at 230 ℃ for 0.5 h. Biomass from other sources also showed good yield and selectivity in this system.

Keywords

• lignin
• waste treatment
• solvent extraction
• selectivity
• organic compounds
• catalysis