聚合物热分解机理的理论研究
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关键词: 聚丁烯二酸二乙酯； 聚氯乙烯； 聚 β-羟基丁二酸；密度泛函理
I
Abstract
Abstract
Recently, the thermal decomposition mechanism of polymer mechanism becomes one of the most active fields. The chemical descriptors of polymers were choosed, used to calculate and predict the property or reaction mechanism of polymers. The quantum chemical descriptors or topology descriptors are obtained directly from repeating units of polymers. Discussing the reation mechanism from monomers of polymers, the calculated results indicate the mechanism of polymer. The paper applied the quantum methods and systematically studied the following three systems. (1) the thermal decomposition of model compounds for Poly (dialkyl fumarate), (2) the thermal dehydrochlorination of model compounds for poly (vinyl chloride), (3) the thermal decomposition of model compounds for β-Poly (L-malate).
作者签名：
日期： 年 月 日
学位论文版权使用授权书
本学位论文作者完全了解学校有关保留、使用学位论文的规定，同意学校保留并向国家有关 部门或机构送交论文的复印件和电子版，允许论文被查阅和借阅。本人授权湘潭大学可以将本学 位论文的全部或部分内容编入有关数据库进行检索，可以采用影印、缩印或扫描等复制手段保存 和汇编本学位论文。
本文采用量子化学方法系统研究了如下 3 个体系；(1)聚丁烯二酸二乙酯的热 分解反应机理；(2)聚氯乙烯脱去氯化氢的热分解反应机理；(3)聚 β-羟基丁二酸的 热分解反应机理。
首先，对聚丁烯二酸二乙酯的热分解反应机理进行了理论研究。在 HF/6-31G(d) 和 B3LYP/6-31G(d)水平上计算了 3 条可能的反应路径。他们分别是路径(Ⅰ)，(Ⅱ) 和 (Ⅲ)。并且在相同水平上计算了聚丁烯二酸二乙酯热分解反应中反应物、过渡 态和产物的平衡构型、振动频率和能量，并在 B3LYP/6-31G(d)水平上经过内禀反 应坐标 (IRC) 分析加以证实。结果表明，三条路径反应的活化能活化能遵从以下 顺序：Ⅲ > Ⅱ> Ⅰ，因此路径(Ⅰ)为主要的反应路径。
2
湘潭大学 学位论文原创性声明
本人郑重声明：所呈交的论文是本人在导师的指导下独立进行研究所取得的研究成果。除了 文中特别加以标注引用的内容外，本论文不包含任何其他个人或集体已经发表或撰写的成果作 品。对本文的研究做出重要贡献的个人和集体，均已在文中以明确方式标明。本人完全意识到本 声明的法律后果由本人承担。
At last, the thermal decomposition of model compounds for β-Poly (L-malate) was
Ⅱ
2006 级硕士研究生毕业论文
investigated theoretically. The geometries, structures, and energies were evaluated for reactants, products, and transition states of the proposed pathways at the B3LYP/6-31G(d) levels. It was found that poly (β, L-malic acid) depolymerized by an unzipping mechanism with generation of fumaric acid which is then partially converted in a mixture of maleic acid and anhydride.
The models in this paper are proved to be accurate and reliable. The thermal decomposition of model compounds for some polymers was investigated theoretically. The results indicate that the density functional theory can provide reasonable and relative energies, and it was applied for the theoretical study the thermal decomposition mechanism.
最后，对聚 β-羟基丁二酸的热分解反应机理进行了wenku.baidu.com究。采用密度泛函理论 (DFT)，在 B3LYP/6-31G(d)水平上对反应过程中反应物、过渡态和产物的平衡构型、 振动频率和能量进行了理论计算。结果表明此热分解反应经历了三个阶段的拉链 式反应。产生反丁烯二酸，然后脱水生成酐。
本文所建立的各种模型精确，可靠。本文从理论上对几种聚合物的热降解机 理进行了分析和研究。结果表明密度泛函理论能够对聚合物热分解反应机理提供 合理的几何结构和相对反应能量。为各种聚合物反应机理的理论探究也提供一定 的指导作用。
Secondly, the thermal decomposition mechanism of HCl elimination reaction of polyvinyl chloride (PVC) is investigated using density function theory with B3LYP/6-31G* method. The three minimum energy paths of the possible reactions were calculated. The geometries, structures, and energies were evaluated for reactants, products, and transition states of the proposed pathways at the B3LYP/6-31G(d) level. To obtain more reliable thermal enthalpies and activation energies, calculations were also carried out using the composite G3B3 approach. The transition state of possible reaction pathway was obtained and verified by internal reaction coordinate (IRC) analysis. The result shows that the ionic reaction mechanism of decomposition mechanism of HCl elimination reaction of vinyl chloride is a main reactive channel. The activation energies of path (2) and path (3) are 55.1 kcal/mol and 41.5 kcal/mol at the B3LYP/6-31G(d) level, respectively.
Candidate Supervisor College Program Specialization Degree University Date
Yan-ling Wang Prof. Xue-Ye Wang Chemistry Physical Chemistry Computer Aided Material Design Master of Science Xiangtan University May, 2009
学校代号 分类号
10530 O641
学 号 200606030996 密 级 公开
硕士学位论文
聚合物热分解机理的理论研究
学位申请人 指导教师 学院名称 学科专业 研究方向
王艳玲 王 学 业 教授 化学学院 物理化学 计算机辅助材料设计
二〇〇九年五月二十五日
The Theoretically Studies on the Decomposition Mechanism of Polymers
Firstly, the thermal decomposition of model compounds for poly (dialkyl fumarate) was investigated theoretically. The three minimum energy paths of the possible reactions were calculated at the HF/6-31G (d) and B3LYP/6-31G(d) levels. Three favorable paths were found (path (Ⅰ), path (Ⅱ) and path (Ⅲ)). Geometries, structures, and energies were evaluated for reactants, products, and transition states of the proposed pathways at the HF/6-31G (d) and B3LYP/6-31G (d) levels. The transition states of possible reaction pathways was obtained at B3LYP/6-31G (d) level and verified by internal reaction coordinate (IRC) analysis. The activation energies for the three reaction paths are in the following order: Ⅲ > Ⅱ> Ⅰ. It has been found that the path (Ⅰ) is considered as the main path for the thermal decomposition of model compounds for poly (dialkyl fumarate).
涉密论文按学校规定处理。
作者签名： 导师签名：
日期： 年 月 日 日期： 年 月 日
2006 级硕士研究生毕业论文
摘要
近年来，聚合物的热分解反应机理的理论研究成为最具活力的研究领域。本 文对几类聚合物反应机理进行了计算和模拟。具体方法是以聚合物的重复单元作 为计算模型，得到各类高聚物的结构特征量子化学参数，通过对聚合物单体反应 机理的研究来探讨聚合物的相关反应机理。
其次，用密度泛函理论方法 (B3LYP)，在 6-31G*水平上对聚氯乙烯 (PVC) 脱去氯化氢热分解反应的机理进行了理论研究，计算了 3 条可能的最低能量反应 路径。计算了氯乙烯脱去氯化氢分子反应中反应物、过渡态和产物的平衡构型、 振动频率和能量，并进一步在 B3G3 水平上进行了能量计算。经过内禀反应坐标分 析 (IRC) 加以证实。结果表明氯化氢的催化作用作为离子反应机理是热分解反应 的主要途径之一，在 B3LYP/6-31G(d)水平上路径 (2) 和路径 (3) 的活化能分别是 55.1 kcal/mol 和 41.5 kcal/mol。
I
Abstract
Abstract
Recently, the thermal decomposition mechanism of polymer mechanism becomes one of the most active fields. The chemical descriptors of polymers were choosed, used to calculate and predict the property or reaction mechanism of polymers. The quantum chemical descriptors or topology descriptors are obtained directly from repeating units of polymers. Discussing the reation mechanism from monomers of polymers, the calculated results indicate the mechanism of polymer. The paper applied the quantum methods and systematically studied the following three systems. (1) the thermal decomposition of model compounds for Poly (dialkyl fumarate), (2) the thermal dehydrochlorination of model compounds for poly (vinyl chloride), (3) the thermal decomposition of model compounds for β-Poly (L-malate).
作者签名：
日期： 年 月 日
学位论文版权使用授权书
本学位论文作者完全了解学校有关保留、使用学位论文的规定，同意学校保留并向国家有关 部门或机构送交论文的复印件和电子版，允许论文被查阅和借阅。本人授权湘潭大学可以将本学 位论文的全部或部分内容编入有关数据库进行检索，可以采用影印、缩印或扫描等复制手段保存 和汇编本学位论文。
本文采用量子化学方法系统研究了如下 3 个体系；(1)聚丁烯二酸二乙酯的热 分解反应机理；(2)聚氯乙烯脱去氯化氢的热分解反应机理；(3)聚 β-羟基丁二酸的 热分解反应机理。
首先，对聚丁烯二酸二乙酯的热分解反应机理进行了理论研究。在 HF/6-31G(d) 和 B3LYP/6-31G(d)水平上计算了 3 条可能的反应路径。他们分别是路径(Ⅰ)，(Ⅱ) 和 (Ⅲ)。并且在相同水平上计算了聚丁烯二酸二乙酯热分解反应中反应物、过渡 态和产物的平衡构型、振动频率和能量，并在 B3LYP/6-31G(d)水平上经过内禀反 应坐标 (IRC) 分析加以证实。结果表明，三条路径反应的活化能活化能遵从以下 顺序：Ⅲ > Ⅱ> Ⅰ，因此路径(Ⅰ)为主要的反应路径。
2
湘潭大学 学位论文原创性声明
本人郑重声明：所呈交的论文是本人在导师的指导下独立进行研究所取得的研究成果。除了 文中特别加以标注引用的内容外，本论文不包含任何其他个人或集体已经发表或撰写的成果作 品。对本文的研究做出重要贡献的个人和集体，均已在文中以明确方式标明。本人完全意识到本 声明的法律后果由本人承担。
At last, the thermal decomposition of model compounds for β-Poly (L-malate) was
Ⅱ
2006 级硕士研究生毕业论文
investigated theoretically. The geometries, structures, and energies were evaluated for reactants, products, and transition states of the proposed pathways at the B3LYP/6-31G(d) levels. It was found that poly (β, L-malic acid) depolymerized by an unzipping mechanism with generation of fumaric acid which is then partially converted in a mixture of maleic acid and anhydride.
The models in this paper are proved to be accurate and reliable. The thermal decomposition of model compounds for some polymers was investigated theoretically. The results indicate that the density functional theory can provide reasonable and relative energies, and it was applied for the theoretical study the thermal decomposition mechanism.
最后，对聚 β-羟基丁二酸的热分解反应机理进行了wenku.baidu.com究。采用密度泛函理论 (DFT)，在 B3LYP/6-31G(d)水平上对反应过程中反应物、过渡态和产物的平衡构型、 振动频率和能量进行了理论计算。结果表明此热分解反应经历了三个阶段的拉链 式反应。产生反丁烯二酸，然后脱水生成酐。
本文所建立的各种模型精确，可靠。本文从理论上对几种聚合物的热降解机 理进行了分析和研究。结果表明密度泛函理论能够对聚合物热分解反应机理提供 合理的几何结构和相对反应能量。为各种聚合物反应机理的理论探究也提供一定 的指导作用。
Secondly, the thermal decomposition mechanism of HCl elimination reaction of polyvinyl chloride (PVC) is investigated using density function theory with B3LYP/6-31G* method. The three minimum energy paths of the possible reactions were calculated. The geometries, structures, and energies were evaluated for reactants, products, and transition states of the proposed pathways at the B3LYP/6-31G(d) level. To obtain more reliable thermal enthalpies and activation energies, calculations were also carried out using the composite G3B3 approach. The transition state of possible reaction pathway was obtained and verified by internal reaction coordinate (IRC) analysis. The result shows that the ionic reaction mechanism of decomposition mechanism of HCl elimination reaction of vinyl chloride is a main reactive channel. The activation energies of path (2) and path (3) are 55.1 kcal/mol and 41.5 kcal/mol at the B3LYP/6-31G(d) level, respectively.
Candidate Supervisor College Program Specialization Degree University Date
Yan-ling Wang Prof. Xue-Ye Wang Chemistry Physical Chemistry Computer Aided Material Design Master of Science Xiangtan University May, 2009
学校代号 分类号
10530 O641
学 号 200606030996 密 级 公开
硕士学位论文
聚合物热分解机理的理论研究
学位申请人 指导教师 学院名称 学科专业 研究方向
王艳玲 王 学 业 教授 化学学院 物理化学 计算机辅助材料设计
二〇〇九年五月二十五日
The Theoretically Studies on the Decomposition Mechanism of Polymers
Firstly, the thermal decomposition of model compounds for poly (dialkyl fumarate) was investigated theoretically. The three minimum energy paths of the possible reactions were calculated at the HF/6-31G (d) and B3LYP/6-31G(d) levels. Three favorable paths were found (path (Ⅰ), path (Ⅱ) and path (Ⅲ)). Geometries, structures, and energies were evaluated for reactants, products, and transition states of the proposed pathways at the HF/6-31G (d) and B3LYP/6-31G (d) levels. The transition states of possible reaction pathways was obtained at B3LYP/6-31G (d) level and verified by internal reaction coordinate (IRC) analysis. The activation energies for the three reaction paths are in the following order: Ⅲ > Ⅱ> Ⅰ. It has been found that the path (Ⅰ) is considered as the main path for the thermal decomposition of model compounds for poly (dialkyl fumarate).
涉密论文按学校规定处理。
作者签名： 导师签名：
日期： 年 月 日 日期： 年 月 日
2006 级硕士研究生毕业论文
摘要
近年来，聚合物的热分解反应机理的理论研究成为最具活力的研究领域。本 文对几类聚合物反应机理进行了计算和模拟。具体方法是以聚合物的重复单元作 为计算模型，得到各类高聚物的结构特征量子化学参数，通过对聚合物单体反应 机理的研究来探讨聚合物的相关反应机理。
其次，用密度泛函理论方法 (B3LYP)，在 6-31G*水平上对聚氯乙烯 (PVC) 脱去氯化氢热分解反应的机理进行了理论研究，计算了 3 条可能的最低能量反应 路径。计算了氯乙烯脱去氯化氢分子反应中反应物、过渡态和产物的平衡构型、 振动频率和能量，并进一步在 B3G3 水平上进行了能量计算。经过内禀反应坐标分 析 (IRC) 加以证实。结果表明氯化氢的催化作用作为离子反应机理是热分解反应 的主要途径之一，在 B3LYP/6-31G(d)水平上路径 (2) 和路径 (3) 的活化能分别是 55.1 kcal/mol 和 41.5 kcal/mol。