Ethylene Dimerization and Oligomerization to 1-Butene and Higher Olefins with Chromium-Promoted Cobalt on Carbon Catalyst

Abstract

Industrial dimerization of ethylene to 1-butene is achieved with catalysts bearing ligand structures and activated by a co-catalyst. Here, we report that a Cr-promoted cobalt oxide on carbon catalyst was able to produce 1-butene with 53.5–82.4% total selectivity at ethylene conversions between 8.9 and 31.5% without the use of a co-catalyst. The Cr-promoted catalyst showed enhanced activity and stability compared to the nonpromoted catalyst. The characterization results revealed that the incorporation of Cr into the cobalt oxide on carbon catalyst was able to decrease the cobalt oxide particle size. Charge transfer from Cr to Co was also observed in the Cr-promoted catalyst compared to monometallic Co and Cr on carbon. The kinetic model built to rationalize the experimental observations predicted a 50% increase in active site dispersion in the Cr-promoted catalyst, which explained the 1.6× apparent reaction rate increase compared to the nonpromoted catalyst.