Highly Active Heterogeneous Catalyst for Ethylene Dimerization Prepared by Selectively Doping Ni on the Surface of a Zeolitic Imidazolate Framework

The production of 1-butene by ethylene dimerization is an important chemical industrial process currently implemented using homogeneous catalysts. Here, we describe a highly active heterogeneous catalyst (Ni-ZIF-8) for dimerization, which consists isolating Ni-active sites selectively located on the crystal surface zeolitic imidazolate framework. Ni-ZIF-8 can be easily prepared simple one-pot synthesis method in site-specific anchoring Ni achieved spontaneously because incompatibility between d8 electronic configuration Ni2+ and three-dimensional framework ZIF-8. full exposure square-planar coordination accounts high catalytic activity Ni-ZIF-8. It exhibits average turnover frequency greater than 1 000 h–1 (1-butene selectivity >85%) at 35 °C 50 bar, far exceeding activities previously reported catalysts many under similar conditions. Moreover, compared to molecular complexes used as has significantly higher stability shows constant during 4 h continuous reaction. Isotopic labeling experiments indicate that over follows Cossee-Arlman mechanism, detailed characterizations combined with density functional theory calculations rationalize this observed activity.