不同酸解聚麦秸产物分析及其动力学

Depolymerization Products and Kinetics of Wheat Straw Using Different Acids

以麦秸为研究对象,解聚剂为HCl、HNO3和H3PO4,对解聚产物进行定性和定量分析,并利用动力学模型描述木糖及糠醛的产生过程。结果表明,解聚液中的产物有葡萄糖、木糖、阿拉伯糖、纤维二糖、乙酸、糠醛、5-羟甲基糠醛。通过引入变量(α,木糖/木聚糖的比值)利用Saeman动力学模型获得了不同温度下,木聚糖的水解速率常数、木糖的转化速率常数以及糠醛的生成速率常数。HCl、HNO3和H3PO4解聚麦秸,木糖的生成活化能分别为55.5、46.3和59.8 k J/mol。结合反应温度、反应时间、反应速率以及木糖和糠醛的浓度,确定最佳解聚条件为:硝酸作解聚剂,在130℃下水解95 min。

The products of wheat straw treated with hydrochloric acid, nitric acid, and phosphoric acid were analyzed and the kinetics of production of xylose and furfural during depolymerization were studied. The results show that the products in the depolymerized wheat straw are glucose, xylose, arabinose, acetic acid, eellobiose, furfural, and 5-hydroxymethyl furfural. The rate constants of xylan hydrolysis, xylose conversion and furfural formation at different temperatures were obtained using the modified Saenmn model by introducing a variable （a, the ratio of xylose and arabinose）. The activation energies of xylose formation with the tested acids（HCl, HNO3, and H3PO4） are 55.5 kJ/mol, 46.3 kJ/mol, and 59.8 kJ/mol, respectively. Combined with reaction temperature, time, the reaction rate, and the concentration of xylose and furfural, the optimized acid treatment for wheat straw is HNO3 depolymerization at 130 ℃ for 95 min.