Selective ethylene dimerization toward 1-butene by a new highly efficient catalyst system and determination of its optimum operating conditions in a büchi reactor

The quantity of heavy and polymeric compounds produced in the industrial reactor is the most important problem of 1-butene plants that leads to the fouling formation and shutting down of the pertinent reactor. Accordingly, a systematic study has been made of the Ti catalyzed dimerization of ethylene using a vicinal halide compound as a new promoter. This study revealed that the addition of 1, 2-dichloroethane (EDC) as new promoter had marked impact on the catalyst performance which led to the improvement of overall 1-butene selectivity, yield of reaction and remarkable decrease of by-products and polymer. It is proposed that the spatial effects of weak coordination of EDC on the Ti active species lead to the decomposition of dimeric TEA into monomeric TEA and the facile generation of the increased number of the active metal sites of responsible for the dimerization of ethylene. The relevant mechanism and reaction between TEA and EDC was disclosed in detail. More specifically, the effects of various operating conditions (i.e. reaction temperature and pressure, molar ratios of TEA/Ti, modifier/Ti and EDC/Ti on ethylene conversion, overall selectivity to 1-butene, byproducts, weight of polymer and yield of reaction were fully assessed and the optimum reaction conditions were determined.

ethylene dimerization, vicinal halide, promoter, heavy and polymeric compounds