β-二酮-茂基二氯化钛/MAO催化体系用于苯乙烯间规聚合

SYNTHESIS OF A TITANIUM COMPLEX CONTAINING β-DIKETONE LIGAND AND ITS CATALYSIS FOR SYNDIOTATIC POLYMERIZATION OF STYRENE

制备了 β 二酮类配体 [O ,O]的茂基二氯化钛配合物CpTi(dbm)Cl2 .实验证明 ,这类配合物在助催化剂甲基铝氧烷MAO作用下 ,可催化苯乙烯间规聚合 .显示较高的活性 (10 7× 10 5gPS molTi·h) .所得聚合物具有较高的间规度 .CpTi(dbm)Cl2 MAO体系催化活性随铝 钛比的增加呈上升而后衰减 ,当铝 钛比为 5 0 0左右时活性最高 ;聚合温度较高时会导致催化活性下降 .对聚合物进行了1 3C

Syndiotactic polystyrene ( s PS) is a new class of thermoplastics and is unusual among polystyrenes for its properties.Since Ishihara reported on the titanium complexes with mono cyclopentadienyl ligand for production of s PS,a lot of catalysis for styrene syndiotactic polymerization has been reported in the literature.A series of half metallocene complexes have been reported in our studies,these catalysts have high stability and activity for olefin polymerization with low molar ratio of aluminium/titanium and produce polymers with different chain microstructures.In the paper,synthesis of half metallocene complexes [CpTi(dbm)Cl 2] and [CpTi(dbm)\-2Cl] containing β diketone ligand are discribed.It is proved by the experiments that [CpTi(dbm)Cl 2] is active for styrene polymerization at 40℃ with MAO activation,and exhibits higher activity than CpTiCl 3.Giving the polymers with high syndiotacticity.For the [CpTi(dbm)Cl 2]/MAO system,the activity is “up and down' type with increase in the Al/Ti molar ratio,and up to the highest when the Al/Ti molar ratio is about 500,10.7×10 5 gPS/molTi·h or so; also the active decreases when the polymerization time is too high.The polymers prepared by [CpTi(dbm)Cl 2] were extracted with boiling n butanone and characterized by 13 C NMR.