文献类型：期刊文献

英文题名：Understanding the acrylates formation from CO2 and ethylene over Ni- and Pd-based catalysts: A DFT study on the effects of solvents, methyl halides, and ligands

作者：Zhu, Youcai[1];Guo, Xing[1];Ding, Xinxin[1];Sun, Li[1];Zhang, Mingguo[1];Liu, Zhen[1]

机构：[1]East China Univ Sci & Technol, Sch Chem Engn, Shanghai 200237, Peoples R China

年份：2022

卷号：518

外文期刊名：MOLECULAR CATALYSIS

收录：;EI(收录号：20220211439014);WOS:【SCI-EXPANDED(收录号:WOS:000789318800003)】；

语种：英文

外文关键词：CO2; Methyl acrylate; M-O bond cleavage; beta-H elimination; Diphosphine ligands

摘要：In this work, two methylation reaction pathways were investigated to explore the role of solvent and I- on the formation of methyl acrylate from coupling of CO2 and ethylene catalyzed by nickel and palladium catalysts in the presence of MeI. The stabilization of non-productive intermediates is inhibited in the gas phase as well as in low-polar solvents, which explains the requirement of high excess of MeI to obtain high yields of methyl acrylate. The energy barrier for M-O bond cleavage as well as the stability of the overall reaction intermediates is consistent with the corresponding halogen electron-donating ability. The different catalytic behaviors of various bidentate ligands on Ni- and Pd-based catalysts were systematically investigated, mainly including dmpe(1,2-bis (dimethylphosphino)ethane), tmeda(tetramethylethylenediamine), dppe(1,2-bis(diphenylphosphino)ethane), dcpe(1,2-bis(dicyclohexylphosphino)ethane) and dtbpe(1,2-bis(di-tert-butylphosphino)ethane). The energy barrier of M-O bond cleavage increases with the enhancement of ligand steric hindrance in the O1 (ester sp(3) O atom) attack mechanism, while the corresponding O2 (carboxylic sp(2) O atom) attack mechanism shows an opposite trend. The energy barrier of beta-H elimination in both catalytic systems is strongly related to the electron-donating ability of the diphosphine ligand substituents. The dcpp(1,3-bis(dicyclohexylphosphino)propane) ligand shows relatively good performance for beta-H elimination among all the investigated ligands in Pdmediated system. In general, diphosphine ligands are superior to diamine ligands in Pd-mediated system in terms of efficiency.