Olefin Oligomerization over Carbon-Supported Cobalt Catalysts

A recent increase in the demand for linear alpha olefins (LAOs) for use in the polymer, surfactant, lubricant, and detergent industry has prompted further study of heterogeneous, oligomerization catalysts for the upgrading of light olefins to oligomer products.  While commercially-viable, homogeneous catalysts are currently employed, the ability to operate with heterogeneous catalysts has the potential to decrease both operational costs and the environmental impact of the industry.  Common problems associated with heterogeneous, oligomerization catalysts, compared to homogeneous complexes, include lower activity, fast deactivation, and poor selectivity towards linear products.  Here, we report on a highly selective cobalt-based catalyst for the linear oligomerization of 1-butene.  Liquid-phase oligomerization of 1-butene was carried out at low temperatures (<100°C). Complex reaction product mixtures were accurately characterized by two-dimensional gas chromatography (GCxGC-MS).  A selectivity of >80% linear oligomers was achieved.  The effects of various synthesis techniques and support materials on dispersion, activity, and selectivity will be discussed.  Kinetic studies were performed to provide a mechanistic understanding of the reaction.  The dynamic nature of the active site was characterized by XRD, in-situ XAS, and in-situ Raman spectroscopy.