中文关键词:Heck反应 负载Pd催化剂 催化机理 催化活性 可重复使用性 英文关键词:The Heck reaction, Supported Pd catalyst, Catalytic mechanism, Catalytic activity, Reusability 基金项目:人社部留学人员科技活动择优资助重点项目（人社厅函[2013]277号）、湖北省自然科学基金计划重点项目（2014CFA094）资助

作者	单位	E-mail
曹莎莎	湖北工业大学材料与化学工程学院	13006351724@163.com
谭金强	湖北工业大学材料与化学工程学院
吴崇刚	湖北工业大学绿色轻工材料湖北省重点实验室	cgwu@mail.hbut.edu.cn

摘要点击次数:1207 全文下载次数:0 中文摘要: 由于催化活性与立体选择性高，Pd催化剂广泛应用于Heck型交叉偶联反应。其催化机理通常依次包括Pd(0)氧化加成、加成、β-H消去、还原性消去等四步。对于无机非金属、有机高分子及有机-无机复合材料负载型Pd催化剂，Pd浓度的升高增大了催化表面积，Pd-负载吸附作用的加强、负载尺寸的减小及表面结构性的增加提高了Pd的分散度，Pd不饱和配位活性位的增多促进了其与反应物形成配位中间体，溶剂对负载溶胀度的增高扩大了Pd与反应物的有效接触面积，而碱的碱性与用量的增加加速了Pd在催化循环中的再生，这些均提高了Pd的催化活性；然而，随着反应温度的单调升高，Pd的催化活性一般先升高，至某一适中温度时达到最高值，之后因Pd的热聚集过于显著转而降低。作为负载，高分子较陶瓷更高地对Pd进行配位调控，使Pd对Heck反应具有更强的立体选择性。Pd-负载吸附作用的强化降低了Pd的流失率与热聚集，Pd活性位的减少降低了其钝化程度；三者分别提高了负载Pd的浓度、分散度及活性位的保持程度，均有利于其可重复使用性的增加。研发催化机理明确、催化活性高、立体选择性强、可重复使用性好的负载型Pd催化剂为Heck反应的发展趋势之一。 英文摘要: Owing to their high catalytic activity as well as stereoselectivity, Pd catalysts have been widely applied to the Heck cross-coupling reactions usually according to a catalytic mechanism comprising four sequential steps of oxidative addition of Pd(0), addition, β-H elimination, and reductive elimination. For ceramic, organic polymer, and organic-inorganic composite supported Pd catalysts, a rise in the Pd concentration increases its catalytic surface area, an enhancement of the Pd-support adsorption, a decrease in the size and an increase in the surface structure of the support raise the Pd degree of dispersion, an increase in the unsaturated coordination sites (UCSs) of the Pd accelerates its coordination with the reaction substrate to form an intermediate, an improvement in the degree of swelling of the support by the solvent expands the effective contact area between the Pd and the reaction substrate, and increases in the basicity and dosage of the base facilitate the Pd regeneration in the catalytic cycle, all of which enhance the catalytic activity of the Pd. Nevertheless, as the reaction temperature is raised steadily, the Pd catalytic activity usually increases first, going through a maximum at an optimum temperature, and then turns to decrease due to too significant thermal aggregation of the Pd. As the support, a polymer coordinates and regulates the Pd more highly than does a ceramic, making it have stronger stereoselectivity for the Heck reactions. Strengthening of the Pd adsorption onto the support reduces the Pd running-off rate as well as thermal aggregation, and a decrease in the Pd UCSs diminishes its degree of passivation, the three of which, enhancing the respective retention degrees of the concentration, degree of dispersion, and UCSs of the supported Pd, all contribute to an increase in its reusability. It has been one of the trends in the Heck reactions to develop supported Pd catalysts of clear catalytic mechanism, high catalytic activity, strong stereoselectivity, and satisfactory reusability. 查看全文查看/发表评论下载PDF阅读器 相关附件：版权转让声明书附件1附件1 -->