Chen YunPing;Cheng XianSu

China.; Fuzhou 350002;College of Material Science and Engineering; Fuzhou University

aliphatic compounds;aromatic compounds;bioenergy;biomass;butanediol;chemical composition;infrared spectroscopy;lignin;polysaccharides;raw materials;renewable energy;rice husks;solvents

Rice husk high boiling solvent lignin (RHL) was prepared by high boiling solvent method, and its characteristics was analysed by using chemical composition analysis, infrared spectroscopy, and 1H-NMR and 13C-NMR spectroscopy. The optimum prepared condition was that the rice husk with 70-90% aqueous solution of 1,4-butanediol was mixed with autoclave, under a certain weight ratio of solid raw material and solvent, heated to 200-220 degrees C for 1.0-3.0 h, then water-insoluble RHL was separated from the liquor reaction mixture by water precipitation. Results suggested that the lower digestion temperature and concentration of 1,4-butanediol were both unfavourable for extracting lignin. Chemical weight-average molecular weight of RHL was 1939 g mol-1, and the residual polysaccharide content was 5.12%. The 1H-NMR spectra of RHL showed the relative intensity ratio, aliphatic over aromatic methoxyl groups, situated at 3.5-3.8 and 3.8-4.0 ppm, respectively. The results from 13C-NMR spectra showed that beta -O-4 bond and beta -5 carbon-carbon linkage were the major linkages between RHL units. The C9+formula of RHL was calculated by the experiment data.