摘要
研究了纤维素在亚临界水中无催化水解及分别添加ZnCl2、FeCl3、CuCl2、AlCl3对水解反应的影响。实验结果显示,无催化剂时,葡萄糖的收率在280℃,60s及(7.0±0.2)MPa时达到最大为14.3%。添加ZnCl2、FeCl3、CuCl2及AlCl3均能促进纤维素的水解及葡萄糖的降解。纤维素的水解及葡萄糖的降解反应级数均为一级。利用一级反应模型对纤维素在260℃水解及葡萄糖的降解反应进行数据拟合,求得了纤维素的水解速率常数(k),葡萄糖的生成速率常数(k1)及葡萄糖的降解速率常数(k2)。添加AlCl3体系中纤维素的水解速率常数(k)大于葡萄糖的降解速率常数(k2),有利于葡萄糖的生成,在260℃,120s及(5.2±0.2)MPa时,葡萄糖收率达到最大为46.05%。添加ZnCl2、CuCl2及FeCl3体系中葡萄糖的降解速率常数(k2)大于纤维素的水解速率常数(k),不利于葡萄糖的生成。XRD分析显示,金属氯化物的加入并没有破坏纤维素的晶体类型,水解残渣仍然保持纤维素Ⅰ型晶体结构。
In subcritical water,the cellulose hydrolysis without catalyst and the effects of catalysts,such as ZnCl2,FeCl3,CuCl2 and AlCl3,on the cellulose hydrolysis were investigated respectively.The results show that the maximum glucose yield of cellulose hydrolysis without catalyst is 14.3% under the conditions as follows：reaction temperature of 280℃,reaction time of 60 s and reaction pressure of （7.0±0.2） MPa.Catalyst ZnCl2,FeCl3,CuCl2 or AlCl3 can accelerate the cellulose hydrolysis and the glucose decomposition simultaneously.It was found that both the cellulose hydrolysis and the glucose decomposition are first order reaction.The experiment data of cellulose hydrolysis and glucose decomposition at 260℃ were fitted by using the first order kinetics equations,and the cellulose hydrolysis rate constant k,the glucose formation rate constant k1 and the glucose decomposition rate constant k2 were obtained.During cellulose hydrolysis in subcritical water,existence of AlCl3 can raise the glucose yield since in the system with AlCl3,the cellulose hydrolysis rate constant k is higher than glucose decomposition rate constant k2.The maximum glucose yield of cellulose hydrolysis with 0.01% AlCl3 is 46.05% under following conditions：reaction temperature of 260℃,reaction time of 120 s and reaction pressure of （5.2±0.2） MPa.The glucose yields of cellulose hydrolysis systems with adding ZnCl2,CuCl2 and FeCl3,respectively,are lower since the glucose decomposition rate constants k2 in those systems are higher than their cellulose hydrolysis rate constants k.XRD analysis shows that the metal chloride catalysts do not change the type of cellulose crystal;and after hydrolysis reaction,the residues still keep the cellulose crystal of type I.
出处
《高校化学工程学报》
EI
CAS
CSCD
北大核心
2010年第4期608-613,共6页
Journal of Chemical Engineering of Chinese Universities
基金
上海市重点资助项目(S30109)
作者简介
马艳华（1980-）．女．山东诸城人．上海大学博士生。
通讯联系人：朱宪。E-mail：xzhu@staff．shu．edu．cn
