单茂钛催化剂的丙烯无规聚合反应及其动力学研究

比较了不同钛化合物／甲基铝氧烷（ＭＡＯ）催化体系的丙烯无规聚合，催化活性次序为ＣｐＴｉ（ＯＲ）３＞ＣｐＴｉ（ＯＰｈ）３＞ＣｐＴｉＣｌ３＞Ｃｐ２ＴｉＣｌ２＞Ｔｉ（ＯＢｕ）４＞ＴｉＣｌ４＞Ｔｉ（ＯＢｕ）２Ｃｌ２，所得聚丙烯用沸庚烷抽提８ｈ，溶解９５％以上，可溶部分经１３Ｃ ＮＭＲ、ＷＡＤＸ、ＦＴＩＲ等分析证明为无规聚丙烯（ａＰＰ），是没有结晶性的弹性体．ＧＰＣ测出其分子量Ｍｗ＝８．０～１０．０×１０４，Ｍｗ／Ｍｎ≈２．０．探索了催化体系ＣｐＴｉ（Ｏ ｎ Ｐｒ）３／ＭＡＯ中钛的浓度、［Ａｌ］／［Ｔｉ］摩尔比，丙烯聚合压力，聚合温度和时间对丙烯聚合反应的影响．研究了该催化体系丙烯聚合反应动力学规律，表观聚合反应速率对催化剂浓度和单体压力（浓度）都呈一级反应关系，表观聚合速率常数ＫＰ＝２９２×１０５ｍｏｌ／Ｌ·ｈ（４０℃）．活化能ΔＥ＝－７．８８×１０３Ｊ·ｍｏｌ－１，碰撞因子Ａ＝１．４１×１０－４ｍｏｌ／Ｌ·ｈ．

STUDIES ON ATACTIC-SPECIFIC POLYMERIZATION OF PROPENE WITH MONONUCLEAR TITANOCENE CATALYSTS

Atactic polypropene was synthsised with homogeneous catalytic systems of varios titanium compounds activated by methylaluminoxane(MAO).The titanium ligands affect both catalytic activity and stereoregularity of polypropene obtained.For novel η 5 cyclopentadienyltri n propyloxy titanium CpTi(O n Pr) 3 /MAO catalytic system,the influencing factors of polymerization temperature,Al/Ti molar ratio and propene pressure on propene polymerization have been studied.The catalytic activity at polymerization temperature 40℃ and Al/Ti molar ratio 200 was 220kgPP/molTi·h. The kinetics of early state propene polymerization with CpTi(O n Pr) 3/MAO has been investigated.The polymer yield increases almost linearly with increasing the titanium or monomer concentration.The apparent rate of polymerization ( R p) versus titanium and monomer concentration appears the first order reaction rule,and the apparent rate constant( K p) is 2 92×10 5mol·L -1 ·h -1 at 40℃.The calculated polymerization activation energy ( ΔE ) is 7 88×10 3J·mol -1 ,while the impact fractor(A) is 1 41×10 4mol·L -1 ·h -1 . After boiling heptane extraction of the polypropene for 8h.The soluble fraction with more than 95% by weight was isolated and characterized as atactic polypropene by 13 C NMR,WAXD and FTIR.The molecular weight( M w) and its distribution( M w/ M n) determined by GPC were 8 0～10 0×10 4 and 2 0 respectively.