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研究了AlCl3催化剂作用下, 水热体系中玉米秸秆中半纤维素组分在温和条件下的选择性转化. 详细考察了反应温度、反应时间和AlCl3用量对半纤维素选择性转化的影响. 原料及反应后的固体残渣分别采用化学滴定、X射线衍射和扫描电镜进行表征. 结果表明, 140 oC下反应1 h可转化玉米秸秆中的大部分半纤维素, 转化率为85.1%; 而玉米秸秆中的绝大部分纤维素和木质素组分仍保留在固体残渣中, 此时纤维素和木质素的转化率分别为10.7%和23.9%. 半纤维素转化的主要液体产物为木糖, 同时含有一些乙酸和糠醛. 升高温度, 将滤液进行进一步反应可促进木糖的转化. 在水/四氢呋喃反应体系中, 滤液的进一步反应有利于乙酰丙酸、甲酸和糠醛的生成. 固体酸催化剂γ-Al2O3/SO42–的加入可进一步提高糠醛的收率.
The selective conversion of hemicellulose components in corn stalks under mild conditions was studied under the action of AlCl3 catalyst.The effects of reaction temperature, reaction time and amount of AlCl3 on the selective conversion of hemicellulose were investigated in detail.Material And the solid residues after the reaction were characterized by chemical titration, X-ray diffraction and scanning electron microscopy.The results showed that most of the hemicellulose in the corn stover was transformed at 140 oC for 1 h, the conversion rate was 85.1%; while the corn stover Most of the cellulose and lignin components remained in the solid residue at which time the conversion of cellulose and lignin was 10.7% and 23.9%, respectively.The main liquid product of hemicellulose conversion was xylose, Containing some acetic acid and furfural.When the temperature is raised, the further reaction of the filtrate can promote the conversion of xylose.In the water / tetrahydrofuran reaction system, the further reaction of the filtrate is conducive to the formation of levulinic acid, formic acid and furfural. The addition of -Al2O3 / SO42- can further improve the yield of furfural.