MgCl_2负载TiCl_4催化剂中内给电子体对活性组分钛的影响

THE EFFECT OF INTERNAL ELECTRON DONOR ON ACTIVE COMPONENT TITANIUM IN MgCl_2-SUPPORTED TiCl_4 CATALYSTS

应用XPSI、R等表征手段研究了以MgCl2为载体,苯甲酸酯、邻苯二甲酸酯以及1,3-二醚为内给电子体的Ziegler_Natta(Z-N)催化剂中内给电子体对活性组分Ti的作用.实验结果表明,不同内给电子体Z-N催化剂中Ti的氧化状态是不同的,给电子体不与Ti直接发生作用,而是通过MgCl2为媒介向Ti发生电荷转移,造成Ti周围电子云密度增大,Ti的氧化状态降低,表现为Ti的结合能下降.

The chemical states of titanium of TiCl4 donor, and MgCl2-supported Ziegler-Natta catalysts obtained by milling method and precipitation method, and the interactions between TICl4, donor, and MgCl2 were studied by XPS and IR methods, and the electron binding energies of Ti2p3 in TICl4 · MgCl2 , TiCl4 · donor and TiC14 · MgC12 · donor and the characteristic adsorption peaks of C - O bond or C-O-C bond in MgCl2· donor, TiCl4· donor and TiCl4· MgCl2＇ donor were compared＇. The results showed that the oxidation states of titanium species in Ziegler-Natta catalysts using different compounds, such as benzoate, phthalate, 1,3-diether as internal electron donors were different. The internal donor did not react directly on titanium, but transfered electron to titanium through MgCl2 as medium, and increased the electron-cloud density of Ti species, and thus decreased the oxidation state and electron binding energy of Ti species.