Wang Lu, Wang Xingyong, Li Hongchen, Chen He, Feng Wanru, Zhao Zerun, Zhao Fujun, Lei Shuai, Hou Zhanggui, Fu Songbao
CNOOC Institute of Chemicals & Advanced Materials, Beijing 102209, China.
Molecules. 2025 Aug 29;30(17):3549. doi: 10.3390/molecules30173549.
The hydroesterification of olefins provides a highly efficient way to produce high value-added ester products from simple and abundant olefin feedstocks. In this work, DFT calculation was performed to investigate the detailed reaction mechanism of propene hydroesterification over Rh(II)/Silicalite-2 catalysts. Three possible mechanistic pathways were systematically explored and compared in terms of their adsorption configurations, reaction energies, and transition-state barriers. Among them, the Carbonylation-First pathway exhibited the most favorable energy profile with the lowest overall kinetic barriers, indicating it to be the most likely way for ester formation. A comparison of methyl butyrate and methyl isobutyrate formation revealed that the linear product is energetically more favorable, particularly along the Carbonylation-First pathway. Moreover, the Rh(II) center demonstrates a different catalytic effect over conventional Rh(I) species by significantly lowering the energy barrier for CO insertion, a key step in both hydroformylation and hydroesterification. These findings provide fundamental insight into the role of Rh(II)/zeolite systems in carbonylation reactions and offer theoretical guidance for the design of catalysts.
烯烃的氢酯化反应提供了一种高效的方法，可从简单且丰富的烯烃原料生产高附加值的酯产品。在这项工作中，进行了密度泛函理论（DFT）计算，以研究Rh(II)/Silicalite-2催化剂上丙烯氢酯化反应的详细反应机理。从吸附构型、反应能量和过渡态能垒方面，系统地探索和比较了三种可能的反应机理途径。其中，羰基化优先途径表现出最有利的能量分布，具有最低的整体动力学能垒，表明它是形成酯的最可能途径。丁酸甲酯和异丁酸甲酯形成的比较表明，线性产物在能量上更有利，特别是沿着羰基化优先途径。此外，Rh(II)中心通过显著降低氢甲酰化和氢酯化反应中关键步骤CO插入的能垒，展现出与传统Rh(I)物种不同的催化效果。这些发现为Rh(II)/沸石体系在羰基化反应中的作用提供了基本见解，并为催化剂设计提供了理论指导。
