Synthesis Of Cobalt(?) Metal-organic Coordination Polymer For Ethylene Oligomerization

The demand for low carbon olefins?butene,hexene and octane etc.?as comononers in production of linear low density polyethylene?LLDPE?is increasing.Ethylene oligomerization with even carbon atom products and a high atomic economy,becomes a leading process for synthesizing low carbon olefins.In this paper,cobalt metal organic coordination polymers containing unsaturated metal active centers are used to catalyze the ethylene oligomerization.The unsaturated metal active sites serve as active centers for catalysis.Firstly,one-dimensional and two-dimensional cobalt metal organic coordination polymers?CoBTC?were synthesized by solvothermal method.The catalytic materials were vacuum activated at different temperatures to obtain CoBTC catalysts.Two kinds of CoBTC catalytic materials and catalysts were then characterized by thermogravimetric analysis,X-ray Diffraction,Infrared Spectra Analysis and Scanning Electron Microscope characterization.Finally,the CoBTC catalysts were used in the ethylene oligomerization reaction.For the one-dimensional CoBTC catalysts,the effects of pretreatment temperature,the amount of catalyst,the reaction pressure on the catalytic performance were investigated.The effects of reaction pressure and cocatalyst type on the catalytic performance were investigated for two-dimensional CoBTC catalysts.The results showed that the oligomerization activities of the two catalysts changed regularly depending on different pretreatment temperatures and the ethylene oligomerization products were mainly C8.The two-dimensional CoBTC catalyst had the highest ethylene agglomeration activity of 3.73×10⁵ gmol^-1?Co?h^-1,and the selectivity of C8 was as high as 98.68%.