第一性原理研究分子在金属表面选择催化反应机理
毕业论文关键词 异佛尔酮 选择性 催化加氢 吸附 反应机理
Title Catalytic hydrogenation of molecule on the metalsurface: understanding the selectivity mechanism fromfirst-principles calculations
Abstract Selective catalytic mechanism of organic molecules on the metalsurfaces,such as the interaction of unsaturated hydrocarbons andtransition metal surface, plays a vital role in heterogeneous catalyticreactions. Many molecules (such as ketones and aldehydes) with multipleunsaturated bonds (such as C=C and C=O double bonds), however, experimentsshow that hydrogenation of C=C bonds are easier to happen than C = O bondsof these molecules. Density functional theory calculation result hasconfirmed the results of the experiments that,C=C double bond is morereactive in all competition route of isophorone catalytic hydrogenationreaction on Pd(111). How to control the metal substrate so as to realizethe catalytic path,such as through hydrogenation on the C = O to productthe necessary industrial alcohol products,is the challenge of selectivecatalysis. This paper will be target researching the adsorption andcatalytic properties of isophorone with catalytic activity on thetransition metal Pd surface,and through the regulation of the metalsubstrate coverage achieved C=O double bond hydrogenation provides thetheory basis for the experiment and industry to understand and control thecatalytic reaction .
Keywords isophorone selectivity catalytic hydrogenation11111111111adsorption reaction mechanism
目次
1绪论..1
1.1催化反应及其重要性.....2
1.2过渡金属钯催化剂的概述及其应用...3
1.3α，β不饱和醛加氢机理及影响因素...3
2方法论....6
2.1密度泛函理论介绍及其优点....6
2.2吸附作用概述.....7
3模拟结果与分析...10
3.1异佛尔酮分子在Pd（111）上的吸附....10
3.2加氢路线及中间产物..12
3.3覆盖率对加氢路线的影响17
结论与展望21
致谢22
参考文献....23
1 绪论近年来，Langmuir-Hinshelwood (LH) 机制广泛应用在金属表面有机分子氢化模型中。事实上，密度泛函理论(DFT)已经研究了在 Pt（111）表面上催化烯烃和酮的加氢反应，并证实了两种反应物（氢分子和有机分子）本质上是沿反应途径与Pt 表面原子相键合的。在化学领域，催化加氢可分为对含有C=O 键、C=C键等双键的物质与含有杂质的 C-X物质加氢[1]。 含有不饱和双键的加氢在加氢催化领域是最主要的一类，因此，工业界和学术界一直以来都致力于研究不饱和物质的催化反应。 但是对于拥有 C=C 和 C=O 双键的多官能团分子的加氢选择性还存在许许多多的问题，比如加氢机制、两种双键的依存性和所观察到的选择性的原因等方面。 目前的问题是在多相催化反应的化学特异性选择中所有竞争路线的固有复杂性。在已知的含有 C=C 和C=O 双键的多官能团分子中，α, β不饱和醛是既具有代表性的,α, β-不饱和醛的选择加氢反应是大量合成精细化学品的关键步骤，尤其是对于香料化学和制药工业[2]。α, β不饱和醛的C=O 双键加氢产物 α, β-不饱和醇，是香料化学、制药化学及其他精细化工领域生产中的反应中间体和重要原料[3]，广泛地应用于有机合成中。