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在超临界条件下水解脱木质素的桉木粉,探讨反应时间对水解率、pH和液体产物分布的影响以及水解动力学。结果表明:反应时间对液化率和pH影响明显,液化率最大为86.8%,pH最小为2.77。水解液的主要组分为低聚糖、己糖、木糖、5-羟甲基糠醛、糠醛、乙酸和一些小分子的呋喃、酮、醇、烯等(产物种类及浓度受反应时间的影响),其中己糖的最大产率为6.07%,木糖的最大产率为3.37%,5-羟甲基糠醛的最大产率为8.48%。动力学研究表明水解反应是一系列连续的一级反应,超临界条件不利于单糖的累积,脱水反应是己糖的主要分解途径。
Hydrolysis of delignified eucalyptus flour under supercritical conditions was carried out to investigate the influence of reaction time on the hydrolysis rate, pH and liquid product distribution as well as the kinetics of hydrolysis. The results showed that the reaction time had a significant effect on the liquefaction rate and pH, with the maximum liquefaction rate of 86.8% and the minimum pH of 2.77. The main components of the hydrolyzate are oligosaccharides, hexoses, xyloses, 5-hydroxymethylfurfural, furfural, acetic acid and some small molecules of furan, ketones, alcohols, alkenes, etc. (the product type and concentration are affected by the reaction time ). The maximum yield of hexose was 6.07%, the maximum yield of xylose was 3.37% and the maximum yield of 5-hydroxymethylfurfural was 8.48%. Kinetic studies show that the hydrolysis reaction is a series of continuous first-order reactions, supercritical conditions are not conducive to the accumulation of monosaccharides, dehydration reaction is the main decomposition of hexoses way.