On the origin of nitrogen-containing promoters in the cobalt-catalyzed methoxycarbonylation of epoxides
作者:Bo Zeng、Mengli Liu、Jianghua He、Jianhua Liu、Zhen Li、Dong Yun、Fang Wang、Chungu Xia、Lin He
DOI:10.1016/j.apcata.2021.118291
日期:2021.8
activity and selectivity in the alkoxycarbonylation of epoxides by a comprehensive in situ IR spectroscopy and DFT studies. In situ IR spectroscopy confirmed the acid-base neutralization of the nitrogenous promoters and HCo(CO)4, resulting in reduction of the acidity of the catalyst. With the reduced acid-derived activity for formation of ethers as by-products, the selectivity of desired esters was increased
迄今为止,尚未研究含氮化合物在钴催化的环氧化物甲氧基羰基化中的详细促进机制。在此,我们通过全面的原位红外光谱和 DFT 研究展示了含氮促进剂与环氧化物烷氧基羰基化的活性和选择性之间的内在相关性。原位红外光谱证实了含氮促进剂和 HCo(CO) 4的酸碱中和,导致催化剂酸度降低。随着生成醚作为副产物的酸衍生活性降低,所需酯的选择性增加。DFT 计算表明,含氮碱可以促进具有较低活化能的钴酰基物质的甲醇分解,这被认为是催化循环中的速率决定步骤。因此,含氮促进剂也提高了羰基化的反应活性。目前的研究将为环氧化物羰基化中长期令人困惑的问题提供新的见解。