石油学报(石油加工) ›› 2017, Vol. 33 ›› Issue (2): 356-363.doi: 10.3969/j.issn.1001-8719.2017.02.022

• 研究报道 • 上一篇    下一篇

基于密度泛函理论的木糖热解制备糠醛的反应机理

张航1,邓胜祥1,田红2,曹小玲2   

  1. 1. 中南大学 能源科学与工程学院,湖南 长沙 410083;
    2. 长沙理工大学 能源与动力工程学院,湖南 长沙 410015
  • 收稿日期:2016-06-02 修回日期:2016-10-08 出版日期:2017-03-25 发布日期:2017-05-27
  • 通讯作者: 张航,男,博士研究生,从事煤和生物质热解气化方面的研究;E-mail:zhanghang4202@126.com E-mail:zhanghang4202@126.com
  • 基金资助:
    国家自然科学基金项目(51276023)的国家自然科学基金国际(地区)合作与交流项目(5131014010)资助

Mechanism of Xylose Pyrolysis to Furfural Based on Density Function Theory

ZHANG Hang1, DENG Shengxiang1, TIAN Hong2, CAO Xiaoling2   

  1. 1. Department of Energy Science and Engineering, Central South University, Changsha 410083, China;
    2. School of Energy and Power Engineering, Changsha University of Science & Technology, Changsha 410015, China
  • Received:2016-06-02 Revised:2016-10-08 Online:2017-03-25 Published:2017-05-27

摘要: 在密度泛函理论(DFT)的基础上,采用B3LYP/6311G方法对木糖热解制备糠醛的反应机理进行动力学分析。木糖热解制备糠醛的反应过程包括开环反应、半缩醛反应和两步消去反应,据此设计6条热解反应路径。对路径中的各构象进行能量梯度全优化和振动频率计算,结果表明, 3种反应类型中,消去反应的活化能最小,而开环反应所需的能量相比其他反应类型都要大。对于木糖,呋喃环的消去反应比吡喃环的消去反应容易发生。Path2A和Path1B的消去反应活化能在所有路径中最低,为67 kJ/mol;而Path2A的开环反应活化能为128 kJ/mol,大于Path1B相应反应的活化能102 kJ/mol,所以Path1B为最优反应路径,其次是Path2A。

关键词: 密度泛函理论, 木糖, 热解, 糠醛, 活化能

Abstract: On the basis of density functional theory (DFT),B3LYP/6311G method was used to investigate xylose pyrolysis mechanism from the perspective of kinetics. Reaction process of xylose pyrolysis to furfural consists of ring opening reaction, hemiacetal and two elimination reactions. Therefore, six reaction paths were designed about xylose pyrolysis to furfural. For each reaction path, the equilibrium geometries were optimized and the vibrational frequencies were calculated. Comparing the six paths, it is found that among the ring opening reaction, hemiacetal and elimination reactions, the activation energy of elimination reaction was the least and that of the opening reaction was the largest. For xylose, the activation energy of pyran ring elimination was much more than furan ring. The third step of elimination activation energy of Path2A and Path1B were all 67 kJ/mol, the lowest among all the paths, while ring opening activation energy of Path2A was 128 kJ/mol, more than 102 kJ/mol to Path1B. So that Path1B was the best reaction path, followed by Path2A.

Key words: density function theory, xylose, pyrolysis, furfural, activation energy