基于密度泛函理论纤维素热解机理热力学研究  

Thermodynamic study of cellulose pyrolysis mechanism based on density functional theory

作　　者：周俊杰[1] 陈曦[1] 汤松臻[1] 李智聪 ZHOU Jun-Jie;CHEN Xi;TANG Song-Zhen;LI Zhi-Cong(School of Mechanical and Power Engineering,Zhengzhou University,Zhengzhou 450001,China)

机构地区：[1]郑州大学机械与动力工程学院,郑州450001

出　　处：《原子与分子物理学报》2025年第5期1-6,共6页Journal of Atomic and Molecular Physics

基　　金：国家自然科学基金(52006199,52376078)。

摘　　要：为了探究纤维素的热解机理,参考相关的实验结果,以纤维素单体模化物为研究对象,采用密度泛函理论的方法,以b3lyp/6-31++g(d,p)为基,对纤维素单体热解反应生成乙醇醛和CO_(2)小分子的反应机理进行动力学研究.纤维素单体热解生成乙醇醛和CO_(2)的反应路径为纤维素单体首先开环,之后裂解生成四糖片段M2和乙醇醛P1,能垒最高为339.1 kJ/mol,四糖片段M2经过脱水形成烯酮结构后再与水分子作用生成羧基,最后发生脱羧反应生成CO_(2),能垒较高为290.1 kJ/mol,不容易发生,整个过程放出98.9 kJ/mol的热量,并对路径反应物、中间体和过渡态进行几何构型全优化,过渡态的振动和频率计算,同时进行不同温度下(400 K、600 K、800 K、1000 K、1200 K)热解过程的热力学分析,对纤维素的热解机理研究将对生物质的热裂解机理研究有重要的意义.In order to explore the pyrolysis mechanism of cellulose,based on b3lyp/6-31++g(d,p),the kinetic study on the reaction mechanism of cellulose monomer to produce glycolaldehyde and CO_(2)small molecules was carried out by referring to the relevant experimental results and using the density functional theory as the research object.The reaction path of cellulose monomer pyrolysis to produce glycolaldehyde and CO_(2)is as follows:cellulose monomer first opens the ring,and then cracks to produce tetraosaccharide fragment M2 and glycolaldehyde P1,with the highest energy barrier of 339.1 kJ/mol.After dehydration,tetraosaccharide fragment M2 forms ketene structure,then reacts with water molecules to form carboxyl group,and finally decarboxylated reaction to produce CO_(2).The high energy barrier is 290.1 kJ/mol,which is not easy to occur.The whole process emits 98.9 kJ/mol of heat.The geometric configurations of path reactants,intermediates and transition states are fully optimized,and the vibration and frequency of transition states are calculated.At the same time,the thermodynamic analyses of the pyrolysis processes at different temperatures(400 K,600 K,800 K,1000 K,1200 K)were made.This study of the pyrolysis mechanism of cellulose will be of great significance for the study of the pyrolysis mechanism of biomass.

关 键 词：纤维素 热解 密度泛函理论 反应机理 

分 类 号：O642[理学—物理化学]