Lewis碱性MOFs限域Pt-Au纳米粒子协同催化α, β-不饱和醛选择性加氢

The development of clean, highly efficient and selective catalyst for hydrogenation of α, β-unsaturated aldehydes to their corresponding allylic alcohols is a challenging and critical subject. In this project, efficient preparation methods will be developed for confinement of metallic nanoparticles within the pore of MOFs containing Lewis basic sites, to afford new Pt-Au@MOFs catalysts with a high efficiency and stability for the hydrogenation of α, β-unsaturated aldehydes under mild conditions. In theory, this study will establish the fundamental structure-property relationship between the physical and chemical properties of the catalysts and their catalytic performance. In addition, the reaction mechanism for selective hydrogenation of α, β-unsaturated aldehydes will be investigated in depth. In technology, efficient preparation methods for the confinement of metallic nanoparticles within MOFs will be developed. Meanwhile, a series of highly efficient and selective Pt-Au@MOFs catalysts will also be obtained for selective hydrogenation of α, β-unsaturated aldehydes to their corresponding allylic alcohols. This study is significant in both theory and practice.

清洁高效、高选择性地催化α, β-不饱和醛加氢生成对应的烯醇是具有挑战性和战略性意义的研究课题。本项目提出以Lewis碱性的MOFs为主体，发展MOFs孔道内限域金属纳米粒子的新技术方法，开发在温和条件下具有高加氢活性、选择性和稳定性的Lewis碱性Pt-Au@MOFs新型催化剂。项目在理论层面上，研究MOFs的物理结构和化学性质与催化反应活性和选择性的关联规律，揭示α, β-不饱和醛选择性加氢的关键因素和反应机理；在技术层面上，开发出有效的制备MOFs限域金属纳米粒子的方法和技术，发展几种可在温和条件下高效、高选择性催化α, β-不饱和醛生成对应α, β-不饱和醇的新型Pt-Au@MOFs催化剂。开展本课题研究具有重要的理论和实际意义。

选择性催化加氢α, β-不饱和醛生成对应的α, β-不饱和醇是一重要的工业反应，它广泛地应用于香精香料、化妆品、医药等精细化学品的合成中。然而，由于α, β-不饱和醛分子中C=O和C=C形成共轭体系，使得它们存在竞争加氢过程，得到的产物往往是α, β-不饱和醛中C=C或C=O以及二者都被加氢的多种物质的混合物。因此，寻找有效的选择性氢化α, β-不饱和醛的催化剂，是一个非常有意义且具有挑战的难题。本项目中我们研发两类选择性催化加氢催化剂: 1) 开发Pt-Lewis酸协同催化剂，该催化剂在常温常压下即可高效地实现肉桂醛选择加氢，肉桂醛转化率>99.9%，同时氢化肉桂醛选择性达>99.9%；2) 开发外延生长法、动力学调控法等制备MOF封装超小金属纳米颗粒(MNPs)复合材料。MOFs孔道内的π电子供体效应可提高限域在孔道内的金属纳米粒子表面的电子密度，同时封装在MNPs外面的MOF层的位阻效应可改变反应底物分子的吸附方向，MOF的电子捐赠效应和位阻效应有利于提高C=O的加氢选择性。如Pt/MOFs表面外延生长一定的MOF层后，在肉桂醛完全转化的条件下，肉桂醛通过C=O加氢生成生成肉桂醇的选择性从55提高到了96%。