丁苯橡胶气相热解产物反应机理的动力学计算与模型

Kinetic calculation and model about reaction mechanism of styrene-butadiene rubber pyrolysis gaseous products

中文关键词: 丁苯橡胶  分子动力学  热解  反应路径  气相产物

英文关键词: styrene-butadiene rubber, molecular dynamics, pyrolysis, reaction paths, gaseous products

中文摘要:

      为了更深入地了解废旧橡胶热解机理，运用分子动力学的方法，对应用广泛的丁苯橡胶的热解过程进行了模拟，并结合模拟结果和密度泛函数对其气相产物的反应路径进行推测计算。模拟结果表明：热解过程主要分为两个阶段，在第一个阶段，主要发生丁苯橡胶链断裂形成短链和单体，第二阶段主要发生单体进一步生成气体；在第一个阶段里，主要产物为1,3-丁二烯，还有部分苯乙烯，反应为放热反应；其中苯乙烯的形成不利于1,3-丁二烯后续生成H2 、CH2=CH2的热解反应；在第二阶段里，1,3-丁二烯热解的主要气相产物为CH2=CH2，中间C—H键上的H原子更容易被夺去；苯乙烯热解的主要气相产物为H2，乙烯基与苯基结合处的H原子最容易被夺去。此外，还会产生CH2=CHCH3、CH4等气体。这将为废旧橡胶热解得到特定的气相产物提供理论依据。

英文摘要:

      In order to understand the pyrolysis mechanism of waste rubber in depth, the pyrolysis process of styrene-butadiene rubber (SBR) that is used widely was simulated by molecular dynamics, and the reaction paths of its gaseous products were predicted by combining the simulation results and density functional function. The simulation results show that the pyrolysis process can be divided into two stages. In the first stage, the short chain and monomer are mainly formed by the chain breaking of SBR. In the second stage, the monomers react further to form gas. In the first stage of pyrolysis, the main product of SBR is 1,3-butadiene and a part of styrene is formed, which is exothermic reaction. The formation of styrene can inhibit the pyrolysis of 1,3-butadiene to H2 and CH2=CH2. The main gaseous product of 1,3-butadiene is CH2=CH2, and the H atom on the intermediate C-H bond is easier to be removed. The main gaseous product of styrene is H2, and the H atom at the junction of vinyl and phenyl is the easiest to be removed. In addition, CH2=CHCH3 and CH4 are produced. This will provide a theoretical basis for the pyrolysis of waste rubber to obtain specific gaseous products.