超支化镍系催化剂构效关系及催化乙烯齐聚机理

Structure-property relationship and mechanism of catalytic ethylene oligomerization of hyperbrached nickel catalyst

采用1.0G超支化大分子(1.0G)、3-取代水杨醛和NiCl26H2O为原料,依次经席夫碱反应和络合反应合成了3种新型具有不同取代基位阻的超支化水杨醛亚胺配体及其镍系催化剂,利用红外光谱(FTIR)、核磁共振氢谱(1HNMR)、紫外光谱(U V-vis)、电喷雾质谱(ESI-MS)及电感耦合等离子体质谱(ICP-MS)等方法对合成出产物的结构进行表征。考察了配体空间位阻、溶剂种类、助催化剂种类及反应条件对催化乙烯齐聚性能的影响。研究结果表明,配体空间位阻对催化乙烯齐聚性能有较大的影响,当以甲苯为溶剂、甲基铝氧烷(M AO)为助催化剂,在最佳反应条件下,超支化邻苯基水杨醛亚胺镍系催化剂催化乙烯齐聚的活性为2.81×10^5g/(mol Ni h),对高碳烯烃(C 10+)的选择性为34.28%。此外,在超支化水杨醛亚胺镍系催化剂催化性能评价的基础上,对其催化乙烯齐聚的机理进行研究。

Three kinds of novel hyperbranched salicylaldimine ligands and nickel catalysts were prepared with 1.0G hyperbranched macromolecule,3-substituted salicylicaldehyde and NiCl26H2O as the raw materials,and the structures were fully characterized by FTIR,1H NMR,UV,ESI-MS and ICP-MS.The effect of ligand steric hindrance,solvent,co-catalyst and reaction conditions on cayalytic property of ethylene oligomerization was investigated.The result showed that the ligand steric hindrance had a significant effect on catalytic property.Under the optimum reaction conditions,the catalytic activity could reach up to 2.81×10^5g/(mol Ni h)and the selectivity of high carbon olefins(C10+)was 34.28%when toluene was used as solvent and MAO as co-catalyst.In addition,the mechanism of catalytic ethylene oligomerization was studied on the base of the evaluation of catalytic performance of hyperbranched salicylaldehyde nickel catalysts.