Understanding and Optimizing the Behavior of Al- and Ru-Based Catalysts for the Synthesis of Polyisobutenyl Succinic Anhydrides
Understanding and Optimizing the Behavior of Al- and Ru-Based Catalysts for the Synthesis of Polyisobutenyl Succinic Anhydrides
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DOI：
10.1021/acs.iecr.2c02003
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发表时间：
2022-09-22
影响因子：
4.2
通讯作者：
Mpourmpakis, Giannis
中科院分区：
文献类型：
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作者：
Morales-Rivera, Cristian A.;Cormack, Glenn;Mpourmpakis, Giannis
聚异丁烯基琥珀酸酐(PIBSA)是汽车工业中的一类重要化学品，广泛应用于润滑油和燃料配方中。然而，这些分子的合成是在高温下通过马来酸酐(MAA)和聚异丁烯(PIB)之间的烯反应进行的。路易斯酸催化剂(如AlCl3)被证明通过降低反应的活化能来促进PIBSA的合成；然而，最终产物(PIBSA)从催化剂上的脱附可能是高度放热的。在这里，我们展示了通过第一性原理计算和动力学模拟相结合的配位体工程策略来优化Al和Ru基催化剂的性能。我们发现，EtAlCl2等烷基氯化物与AlCl3一样，保留了相对较低的活化势垒，同时降低了最终产物的脱附能(PIBSA)。此外，我们还研究了金属氧化态和配体对烯反应性能的影响。我们证明，根据金属氧化状态和配体类型的不同，协同机制和逐步机制之间存在竞争。我们发现了一种Ru(II)催化剂，RuCl2中心点2H(2)O，表现出增强的活性，但稳定性较低。总体而言，我们的工作确定了具有工业重要性的催化剂，可以减少强化过程所需的能量输入，并强调了与催化剂性能相关的挑战。
Polyisobutenyl succinic anhydrides (PIBSAs) are an important class of chemicals in the automotive industry due to their wide use in lubricant and fuel formulations. However, the synthesis of these molecules takes place at elevated temperatures through the ene reaction between maleic anhydride (MAA) and polyisobutylene (PIB). Lewis acid catalysts (e.g., AlCl3) have been shown to facilitate PIBSA synthesis by lowering the activation energy of the reaction; however, the desorption of the final product (PIBSA) from the catalyst can be highly endergonic. Herein, we demonstrate ligand engineering strategies to optimize the performance of Al-and Ru-based catalysts by combining first-principles calculations with kinetic modeling. We discover that alkyl chlorides such as the EtAlCl2 retain relatively low activation barriers like AlCl3, while lowering the desorption energy of the final product (PIBSA). In addition, we address metal oxidation state and ligand effects on the ene reaction performance of Ru-based catalysts. We demonstrate that depending on the metal oxidation state and type of ligands there is a competition between concerted and stepwise mechanisms. We uncover a Ru(II) catalyst, RuCl2 center dot 2H(2)O, exhibiting enhanced activity but suffering from low stability. Overall, our work identifies catalysts of industrial importance that can reduce the energy input required for intensified processes and highlights challenges associated with catalyst performance.