中性镍催化剂的研制及其对乙烯聚合反应的催化性能  

Preparation of Neutral Nickel(Ⅱ) Catalysts and Their Catalytic Performance for Ethylene Polymerization

作　　者：单玉华[1] 孙俊全[1] 徐永进[1] 崔永刚[1] 

机构地区：[1]浙江大学材料与化工学院联合化学反应工程研究所,浙江杭州310027

出　　处：《催化学报》2004年第9期735-740,共6页

基　　金：国家自然科学基金资助项目 ( 2 0 0 740 2 8;2 0 3 740 43 ) ;中国石油化工股份有限公司资助课题 (X5 0 0 0 3 0 )

摘　　要：通过环己基氯与对位取代酚烷基化方法在酚的氧邻位引入高位阻的环己基 ,再经甲酰化、胺缩合及配合制得两种新的中性镍配合物 [O (3 C6H11) (5 CH3 )C6H2 o C(H)∶N 2 ,6 (i Pr) 2 C6H3 ]Ni(Ph3 P) (Ph)和 [O (3 C6H11) (5 Cl)C6H2 o C(H)∶N 2 ,6 (i Pr) 2 C6H3 ]Ni(Ph3 P) (Ph) .在Ni(COD) 2 (COD环辛二烯 )存在下 ,两种配合物均可有效地催化乙烯聚合反应 ,且后者的催化性能明显优于前者的催化性能 .两种配合物对温度很敏感 ,适宜的聚合温度是 4 5～ 5 5℃ .随着乙烯压力的提高 ,催化剂的活性显著提高 ,聚合物的粘均分子量 (Mη)显著增大 ,带支链的聚乙烯减少 .在n(Ni(COD) 2 ) /n(cat) =3,V(PhCH3) =30ml,p(C2 H4 ) =1 2MPa ,θ =4 5℃和t=2 0min的条件下 ,前者配合物的活性为 3 6 2× 10 5g/ (mol·h) ,聚乙烯的Mη=4 94×10 4;后者配合物的活性为 7 2 9× 10 5g/ (mol·h) ,聚乙烯的Mη=7 16× 10 4.两种配合物添加极性物质后的活性顺序为 :乙醚>四氢呋喃 >乙酸乙酯 >水 >乙醇 .其中 ,乙醚和四氢呋喃可使催化剂活性提高 .The neutral nickel(Ⅱ) catalysts [O-(3-C 6H 11 )(5-CH 3)C 6H 2-o-C(H)∶N-2,6-(i-Pr) 2C 6H 3]Ni-(Ph 3P)(Ph) (4a) and [O-(3-C 6H 11 )(5-Cl)C 6H 2-o-C(H)∶N-2,6-(i-Pr) 2C 6H 3]Ni(Ph 3P)(Ph) (4b) were prepared facilely. The bulky group cyclohexyl (C 6H 11 -) was coupled to the ortho position of phenoxide readily by Friedel-Crafts alkylation of para-substituted phenols with C 6H 11 Cl, followed by formylation and condensation to form the salicylalcdimine ligands [HO-(3-C 6H 11 )(5-CH 3)C 6H 2-o-C(H)∶N-2,6-(i-Pr) 2C 6H 3] (3a) and [HO-(3-C 6H 11 )(5-Cl)C 6H 2-o-C(H)∶N-2,6-(i-Pr) 2C 6H 3] (3b). The ligands 3a and 3b reacted with bis(triphenylphosphine)nickel(phenyl)chloride, respectively, to form the complexes 4a and 4b. The 4a and 4b were used as the catalysts for C 2H 4 polymerization with Ni(COD) 2 as a cocatalyst, but the productivity and the molecular mass of polyethylene (PE) were higher with 4b than those with 4a. The catalysts were very sensitive to temperature and the suitable polymerization temperature was 45～55 ℃. The activity of the catalysts and the viscosity molecular mass (M η) of PE increased remarkably, whereas the extent of branching decreased with increasing C 2H 4 pressure. Under the conditions of n(Ni(COD) 2) / n(cat) =3, V(PhCH 3)=30 ml, p(C 2H 4)=1 2 MPa, θ=45 ℃ and t=20 min, the activity was 3 62×10 5 g/(mol·h) and the M η was 4 94×10 4 with 4a, while the activity was 7 29×10 5 g/(mol·h) and the M η was 7 16×10 4 with 4b. The catalysts exhibited good tolerance toward the polar species under mild conditions, and the tolerance extent decreased in the order: EtOEt>THF>CH 3COOEt>H 2O>EtOH. Among them, the EtOEt and THF improved the catalyst performance.

关 键 词：中性镍催化剂 邻环己基水杨醛亚胺配体 乙烯 聚合 聚乙烯 

分 类 号：O643.3[理学—物理化学]