十溴二苯乙烷热解机理的理论研究  

Theoretical Study on Pyrolysis Mechanism of Decabromodiphenyl Ethane

作　　者：龙洋 汪峣 姜宇 黄金保 欧建开 段文婧 田双 LONG Yang;WANG Yao;JIANG Yu;HUANG Jin-bao;OU Jian-kai;DUAN Wen-jing;TIAN Shuang(School of Physics and Mechatronics Engineering,Guizhou Minzu University,Guiyang 550025,China;Engineering Talent Practice Training Center,Guizhou Minzu University,Guiyang 550025,China)

机构地区：[1]贵州民族大学物理与机电工程学院,贵州贵阳550025 [2]贵州民族大学工程技术人才实践训练中心,贵州贵阳550025

出　　处：《塑料科技》2024年第3期33-38,共6页Plastics Science and Technology

基　　金：贵州省高等学校特色重点实验室建设项目(黔教合KY字[2021]003);贵州省科学技术基金项目(黔科合基础-ZK[2021]278);贵州省普通高等学校青年科技人才成长项目(黔教合KY字[2021]113)。

摘　　要：为了深入了解十溴二苯乙烷(DBDPE)热解机理以及主要产物演化过程,采用密度泛函理论(DFT)方法M06-2X/6-311G(d,p)研究DBDPE热降解反应机理,设计DBDPE热解可能的反应路径,并对其反应路径进行动力学和热力学计算。结果表明:DBDPE单分子初始热解主要以脂肪族H_(2)C—CH_(2)键的断裂为主,形成大量的五溴苄基自由基;C_(aromatic)—Br键断裂产生溴自由基是竞争反应通道,溴自由基与五溴苄基自由基能进一步反应生成五溴苄基溴。初始反应产生的五溴苄基自由基和溴自由基能促进DBDPE的分解,均以抽提脂肪族H_(2)C—CH_(2)键上氢原子为主,反应能垒分别为21.9 kJ/mol和38.3 kJ/mol,导致五溴甲苯、五溴苯乙烯、六溴苯和溴化氢的形成。在DBDPE与氢自由基热解反应中,氢自由基的加入降低了DBDPE热解的反应能垒,其中将氢自由基加到C_(aromatic)—CH_(2)键的苯环碳上的反应能垒为最低(17.9 kJ/mol),其热解反应的主要产物为溴化氢、溴化二苯乙烷和溴化单芳香族化合物等。In order to further understand the pyrolysis mechanism of decabromodiphenyl ethane(DBDPE)and the evolution process of its main products,the thermal degradation reaction mechanism of DBDPE was studied using density functional theory(DFT)method M06-2X/6-311G(d,p).Possible reaction paths for DBDPE pyrolysis were designed,and the kinetic and thermodynamic parameters of various reaction pathways were calculated.The results show that the initial pyrolysis of DBDPE is dominated by the fracture of aliphatic H_(2)C-CH_(2) bond,which results in the formation of a large number of pentabromobenzyl radicals.The bromine radical produced by C_(aromatic)-Br bond fracture is a competitive reaction channel,and the bromine radical can further react with the pentabromobenzyl radical to form pentabromobenzyl bromide.The pentabromobenzyl radicals and bromine radicals produced in the initial reaction can promote the decomposition of DBDPE,which are mainly reflected in the abstraction of H atoms from aliphatic H_(2)C-CH_(2) bonds with energy barriers of 21.9 kJ/mol and 38.3 kJ/mol,respectively,resulting in the formation of pentabromotoluene,pentabromostyrene,hexabromobenzene,and hydrogen bromide.In the pyrolysis reaction processes of DBDPE with hydrogen radical,the addition of hydrogen radical reduces the reaction energy barrier of DBDPE pyrolysis,and the reaction energy barrier of adding hydrogen radical to the aromatic-carbon of C_(aromatic)-CH_(2) of DBDPE is the lowest(17.9 kJ/mol).The main products of co-pyrolysis of DBDPE with H radicals are hydrogen bromide,polybrominated diphenylethane,and brominated monoaromatic compounds.

关 键 词：十溴二苯乙烷 热解机理 密度泛函理论 反应路径 

分 类 号：O642[理学—物理化学]