Abstract Hydroalkoxycarbonylation of olefins has been considered to be one of the most attractive methods to synthesize esters. Controlling the regioselectivities of linear esters (L) and branched esters (B) is a challenging project for researchers working in this reaction. Although most of the attention has been paid to control the regioselectivity through ligand design in homogeneous catalytic systems, study in the area is still limited. Herein, Ru-clusters/CeO2 is employed as a heterogeneous catalyst for the hydromethoxycarbonylation of styrene without any additives. After optimization of the reaction conditions, the conversion of styrene is > 99% with 83% and 12% regioselectivity of linear and branched ester, respectively. By using different supports (CeO2 (nanoparticle), CeO2-rod, and CeO2-cube), three catalysts including Ru-clusters/CeO2, Ru/CeO2-rod, and Ru/CeO2-cube are prepared and applied in the reaction. Structural characterizations demonstrate that the L/B ratio is related to the Ru size of supported Ru catalysts. Further Raman characterization and NH3-TPD demonstrate that the metal-support interaction and the concentration of oxygen vacancy of the catalyst have a great influence on the Ru size. The mechanism and kinetic analysis for this reaction are also investigated in this work.

中文翻译：

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使用 Ru-clusters/CeO2 催化剂对苯乙烯进行线性区域选择性氢甲氧基羰基化

摘要 烯烃的氢烷氧基羰基化被认为是合成酯类最有吸引力的方法之一。控制直链酯 (L) 和支链酯 (B) 的区域选择性对于从事该反应的研究人员来说是一个具有挑战性的项目。尽管大部分注意力都集中在通过均相催化体系中的配体设计来控制区域选择性，但该领域的研究仍然有限。在本文中，Ru-clusters/CeO2 用作苯乙烯的氢甲氧基羰基化的多相催化剂，无需任何添加剂。优化反应条件后，苯乙烯的转化率 > 99%，直链和支链酯的区域选择性分别为 83% 和 12%。通过使用不同的载体（CeO2（纳米颗粒）、CeO2 棒和 CeO2 立方体），三种催化剂包括 Ru-clusters/CeO2、制备了 Ru/CeO2-rod 和 Ru/CeO2-cube 并应用于反应中。结构表征表明 L/B 比与负载的 Ru 催化剂的 Ru 尺寸有关。进一步的拉曼表征和 NH3-TPD 表明，金属-载体相互作用和催化剂的氧空位浓度对 Ru 尺寸有很大影响。在这项工作中还研究了该反应的机理和动力学分析。