Affiliation:
1. Department of Chemical and Biomolecular Engineering National University of Singapore 117576 Singapore
2. Institute of Sustainability for Chemicals, Energy and Environment Agency for Science, Technology and Research (A*STAR) 1 Pasek Road Jurong Island 627833 Singapore
Abstract
AbstractCatalytic ethylene oligomerization is important in the petrochemical industry, as it produces valuable products like linear alpha‐olefins (LAOs) for the synthesis of polymers and specialty chemicals. Catalysts, typically transition metal complexes or metal‐containing materials, play a crucial role in selective oligomerization by providing active sites for ethylene activation and controlling product distribution. Recently, defective metal‐organic frameworks (MOFs) with well‐defined structures and unsaturated active sites have emerged as potential catalysts for ethylene oligomerization. In this study, we employ density functional theory calculations to investigate the energetic selectivity of competing pathways (including dimerization, isomerization and trimerization) during ethylene oligomerization on defective HKUST‐1 supported metal hydrides (H−M–DHKUST‐1, M: Co, Ni, Ru, Rh and Pd). On all the five hydrides, ethylene dimerization is found to be more preferential than trimerization and isomerization. In the microenvironment of defective paddlewheel of HKUST‐1, isomerization is highly unfavorable compared with dimerization because of high energy required for chain walk, and 1‐butene is expected to be the major product on all the five hydrides. Analysis of NBO charges reveals a notable reduction in cationic nature at the metal site on H−Ru–DHKUST‐1, which facilitates β‐hydride elimination for dimerization. The microscopic insights from this computational study might facilitate the rational design of new MOFs and other MOF‐supported catalysts for selective ethylene oligomerization.
Funder
National University of Singapore