以3-溴水杨醛和取代苯胺为原料合成了水杨醛亚胺配体(1a~1c)及其钛配合物(2a~2c),并在助催化剂甲基铝氧烷(MAO)的作用下将配合物2a~2c在常压下催化乙烯聚合,利用红外、凝胶色谱(GPC)和差示扫描量热法(DSC)对聚合物进行分析。考察了配体结构、聚合温度、n(Al)∶n(Ti)及催化剂用量对聚合行为的影响。结果表明,在35℃、n(Al)∶n(Ti)=2 000∶1条件下,配合物2a的催化活性最高,可达1.40×10⁶ g_PE/(mol_Ti·h),随着亚胺基苯环上取代基空间位阻的增大,所得聚乙烯的分子质量进一步增加,配合物2c所得聚乙烯重均分子质量(M_w)达到8.3×10⁵ g/mol、分子质量分布(PDI)为2.6。

Salicylaldehyde imine ligands (1a-1c) and its titanium complexes (2a-2c) are synthesized from 3-bromosalicylic aldehyde and substituted aniline,and their structures are characterized by means of ¹HNMR,¹³CNMR and elemental analysis.Under the action of methylaluminoxane (MAO) co-catalyst,the complexes 2a-2c are used to catalyze ethylene polymerization at atmospheric pressure.The polymers obtained are analyzed through using IR,gel permeation chromatography (GPC) and differential scanning calorimetry (DSC).The influences of ligand structure,polymerization temperature,n(Al)∶n(Ti) and catalyst dosage on polymerization behavior are investigated.Results show that under the conditions of 35℃,0.1 MPa and n(Al)∶n(Ti)=2 000∶1,the catalytic activity of complex 2a reaches the highest,being 1.40×10⁶ g_PE/(mol_Ti·h).As the steric hindrance of the substituents on the imine benzene ring increases,the molecular weight of resulted polyethylene further increases.The weight average molecular weight (M_w) of polyethylene obtained over complex 2c reaches 8.3×10⁵ g·mol^-1,and the molecular weight distribution (PDI) is 2.6,indicating good controllability of the polymerization process.

谢玉(1998-),女,硕士生,研究方向为过渡金属催化剂与烯烃聚合,xieyu0606@163.com;李君华(1982-),男,博士,教授,研究方向为烯烃聚合,通讯联系人,lijunhua0521@163.com。