“扫帚型”镍系催化剂的合成及催化乙烯齐聚的性能

Synthesis and Use in Ethylene Oligomerization Catalysis of Nickel Catalyst Supported by “Broom Molecule”Ligand

以直链十四胺为核的低代"扫帚型"大分子、水杨醛和Ni Cl2为原料,依次通过希夫碱反应和络合反应合成了一种新型的"扫帚型"水杨醛亚胺镍催化剂,采用傅里叶变换红外光谱、核磁共振氢谱和紫外-可见分光光度计证实其合成产品的结构与理论结构相符。在甲基铝氧烷(MAO)活化下,该催化剂具有良好催化乙烯齐聚的性能,且随着反应压力的升高和Al/Ni(摩尔比)增加,其催化活性增大;在反应温度为25℃,反应压力为0.5 MPa,Al/Ni摩尔比为1500时,该催化剂的活性可达2.33×106g/(mol Ni·h),聚合产物主要是C8以下的低碳烯烃,含量高达94%以上。相同条件下,其催化乙烯齐聚的活性高于与其具有类似结构的超支化镍系催化剂。

A novel nickel（ II） catalyst supported by＂broom molecule＂salicylaldiminato ligand was synthesized by Schiff base reaction and an complex reaction with salicylaldehyde,using nickel chloride and low generation ＂broom molecule＂as materials. The structure of the catalyst was fully characterized by FT-IR,1H-NMR,and UV. The complexe displays high catalytic activity in selective ethylene oligomerization with methylaluminoxane（ MAO） as cocatalyst. The catalytic activity increases with increase of the reaction pressure and the Al / Ni ratio. The highest activity of 2. 33 × 106 g /（ mol Ni·h） and 94% selectivity of C4~ C8 olefins are obtained under the conditions of the reaction time of 0. 5 h,the reaction pressure of 0. 5 MPa and the Al / Ni mole ratio of 1500. Under the same polymeric conditions,the catalytic activity of novel nickel（ II） catalyst supported by＂broom molecule＂salicylaldiminato ligand is higher than that of the hyperbranched nickel catalyst in ethylene oligomerization.