Co-doped Metal-Organic Framework as a Heterogeneous Catalyst for Ethylene Dimerization

The Co-MOF-5 catalyst was synthesized by substituting Zn2+ ions with Co2+ ions within the Zn4O metal clusters of MOF-5, achieved via direct agitation at room temperature. The removal of solvent molecules that exhibit additional coordination with Co2+ can be accomplished through high-temperature treatment, thereby enabling the catalyst to function effectively in ethylene dimerization reactions. At 10 atm (1 atm=101325 Pa) and 25 degrees C, with Et2AlCl as a cocatalyst, it showed significant activity and 1-C4 selectivity. At a Co/(Co+Zn) molar ratio of 20%, the oligomerization activity of ethylene was observed to be 5.38x105 g<middle dot>mol-1<middle dot>h-1. Additionally, the selectivity for C4 products was recorded at 97.11%, with 1-butene constituting 88.06% of the resultant product. Density functional theory (DFT) calculations corroborated that the ethylene oligomerization process catalyzed by Co-MOF-5 adheres to the Cossee-Arlman mechanism. Co-MOF-5 not only facilitates the dimerization process effectively but also directs the reaction pathway to preferentially yield 1-C4. Consequently, Co-MOF-5 presents significant potential for applications in industrial catalysis and organic synthesis, particularly in processes that necessitate highly selective products. By further optimizing and modifying the structure and reaction conditions of Co-MOF-5, it is anticipated that its catalytic performance can be enhanced, thereby advancing the development and application of ethylene dimerization reaction technologies.