Generation of xylose solutions from Eucalyptus globulus wood by auto hydrolysis-posthydrolysis processes:: Posthydrolysis kinetics
Generation of xylose solutions from Eucalyptus globulus wood by auto hydrolysis-posthydrolysis processes:: Posthydrolysis kinetics
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DOI：
10.1016/s0960-8524(01)00044-x
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发表时间：
2001-09-01
影响因子：
11.4
通讯作者：
Parajó, JC
中科院分区：
文献类型：
--
作者：
Garrote, G;Dominguez, H;Parajó, JC
在选定的操作条件下（自水解反应）用水处理桉树木材样品，以获得含有半纤维素分解产物（主要是乙酰化低聚木糖、木糖和乙酸）的液相。在进一步的酸催化步骤（水解后反应）中，低聚木糖转化为木糖，木糖是进一步发酵的碳源。通过在100.5 ℃、115 ℃、125 ℃或135 ℃下在含有0.5、1.0、1.5或2wt%催化剂（硫酸）的介质中使含木寡糖的液体反应来建立控制后水解步骤的动力学模式。测定了低聚木糖、木糖、糠醛和乙酸浓度的时间过程，并通过动力学模型解释了结果，该模型允许密切再现实验数据。在各种实验条件下，低聚木糖几乎定量转化为木糖。低聚木糖水解的一级动力学系数（k（1），h（-1））与温度（T K）和硫酸摩尔浓度（C）的关系式为Ink（1）= 36.66 + 1.00 In C - 108.0/（8.314 T）。乙酰基的水解遵循一级动力学。相应的动力学系数（k（a），h（-1））与操作条件的关系式为Ink（a）= 26.80 + 1.18InC- 73.37/（8.314T）。(C)2001爱思唯尔科技有限公司版权所有。
Eucalyptus wood samples were treated with water under selected operational conditions (autohydrolysis reaction) to obtain a liquid phase containing hemicellulose-decomposition products (mainly acetylated xylooligosaccharides, xylose and acetic acid). In a further acid-catalysed step (posthydrolysis reaction), xylooligosaccharides were converted into xylose, a carbon source for further fermentation. The kinetic pattern governing the posthydrolysis step was established by reacting xylooligosaccharide-containing liquors at 100.5 degreesC, 115 degreesC, 125 degreesC or 135 degreesC in media containing 0.5, 1.0, 1.5 or 2 wt% of catalyst (sulphuric acid). The time course of the concentrations of xylooligosaccharides, xylose, furfural and acetic acid were determined, and the results were interpreted by means of a kinetic model which allowed a close reproduction of the experimental data. Almost quantitative conversion of xylooligosaccharides into xylose was achieved under a variety of experimental conditions. The first-order, kinetic coefficient for xylooligosaccharide hydrolysis (k(1), h(-1)) varied with both temperature (T K) and molar sulphuric acid concentration (C) according to the equation Ink(1) = 36.66 + 1.00 In C - 108.0/(8.314T). The hydrolysis of acetyl groups followed a first-order kinetics. The cor responding kinetic coefficient (k(a), h(-1)) was correlated with the operational conditions by the equation Ink(a) = 26.80 + 1.18 In C - 73.37/(8.314T). (C) 2001 Elsevier Science Ltd. All rights reserved.