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在乙烯基合成中对覆盖范围依赖的选择性限制的机制见解

Gregory L Novotny¹, Prashant Deshlahra¹

¹Department of Chemical and Biological Engineering, Tufts University, Medford, Massachusetts, 02155, USA.

|November 3, 2024

概括

了解催化剂的行为是可持续化学的关键. 这项研究揭示了酸盐和乙烯在表面的分解如何限制乙烯酸乙烯合成的选择性,为催化剂设计提供了见解.

科学领域:

催化剂是一种催化剂.
表面科学是一门学科.
可持续化学可持续化学

背景情况:

改善可持续化学过程的催化剂需要了解它们的活动,选择性和稳定的基本原子起源.
乙乙烯 (VA) 合成是一种关键的工业过程,其中催化剂选择性通常受到分解途径的限制.

研究的目的:

研究负责分解产品形成的基本步骤,这些步骤限制了乙酸乙烯在 (Pd) 表面合成期间的选择性.
阐明乙酸和乙烯分解的机制及其与乙烯酸乙烯形成的竞争.

主要方法:

使用密度函数理论 (DFT) 计算来建模反应路径.
采用稳态动力学分析来了解反应速率和覆盖范围.
检查了包括C-H激活,C-O形成和C-C裂变在内的基本步骤.

主要成果:

乙酸的形成和与乙烯的合是VA形成周期的核心,但两者都可以分解为CO2.
乙酸和乙烯的分解都通过在乙酸空位上通过C-H激活启动.
非氧化乙烯分解,特别是通过乙二烯中间体,与氧化途径相比,显示出明显较低的能量障碍,在相关的稳定状态覆盖范围内与VA形成竞争.

结论:

乙烯和乙酸盐在Pd表面的分解显著影响了乙烯酸乙烯合成的选择性.
乙烯分解很容易,但取决于覆盖范围,影响VA形成和稳定状态条件下分解之间的平衡.
这些发现为优化催化剂设计和预测金属表面的VA合成速率和选择性提供了详细的机制框架.

关键词:

覆盖范围的影响在 DFT 方面,它是最重要的.运动学运动学氧化合是氧化合的方法之一.反应机制的反应机制

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