桉木屑在离子液体C4H8SO3HmimHSO4催化下液化行为研究

摘要

Eucalyptus sawdust was liquefied in ethylene glycol under atmospheric pressure using 1-(4-sulfobutyl)-3-methylimidazolium hydrosulfate([C4H8SO3Hmim]HSO4) as catalyst.The effects of the reaction time, temperature and dosage of catalyst on the liquefaction yield and the distribution of liquefaction products were studied.The results showed that the optimal conditions of liquefaction were: 10g eucalyptus sawdust, 60g ethylene glycol, 10 mmol [C4H8SO3Hmim]HSO4, 160 ℃ and 150 min.The liquefaction yield was up to 96.41% under the optimal conditions.The Fourier transform-infrared (FT-IR) spectra, thermal gravimetric and the X-ray diffraction analysis of the residual showed that the major component in the residue was cellulose with high crystallinity.The FT-IR analysis of water-insoluble products showed that water-insoluble products mainly included degradation products from lignin.The GC-MS analysis showed the water-soluble products mainly included levulinic acid and methyl levulinate which was originated from cellulose.%以乙二醇为溶剂,在1-磺酸丁基-3-甲基咪唑硫酸氢盐([C4H8SO3Hmim]HSO4)酸性离子液体催化下,进行桉木屑的液化反应.考察了反应温度、反应时间、催化剂用量对液化率以及产物分布的影响,并对液化产物进行了表征.结果表明:在最优液化条件10 g桉木屑,60 g乙二醇,[C4H8SO3Hmim]HSO4用量为10 mmol,液化温度为160 ℃,液化时间150 min下,桉木屑的液化率最高可达96.41%.在离子液体催化下,桉木屑中的半纤维素和木质素快速液化;液化残渣的主要成分为未降解的结晶区纤维素(结晶度75%左右),液化产物水不溶性级分主要为木质素的降解产物,液化产物水溶性级分主要由纤维素的降解产物乙酰丙酸以及乙酰丙酸甲酯组成.