丁二烯气相聚合的负载型稀土催化剂研究

合成了负载型稀土催化剂,并将其用于丁二烯气相聚合.研究表明,硅胶负载Nd(naph)₃-Al(i-Bu)₃-Al(i-Bu)₂Cl催化体系具有相当高的催化活性和立体定向性,其最佳组成:n(Al)/n(Nd)=40～60,n(Cl)/n(Nd)=3～7.添加适量单体丁二烯或异戊二烯,尤其是添加丁二烯,可成倍提高催化活性,随着聚合反应的进行,其速率在10min内迅速增加并达到峰值,随后降低,动力学行为属衰减型.所得聚丁二烯的分子量在几十万至百万,凝胶含量小于6%,顺-1,4结构含量达到98%左右.

Studies on the Supported Rare Earth Catalyst of Gas Phase Polymerization of 1,3-Butadiene

The supported rare earth catalytic system was synthesized and used in the gas phase polymerization of 1,3-butadiene (Bd) successfully. It is found that the catalyst of silica gel supported Nd(naph) 3-Al(i-Bu) 3-Al(i-Bu) 2Cl has a rather high catalytic activity and high sterospecificity. The catalytic system was found to have an excellent activity when n(Al)/n(Nd)=40-60, n(Cl)/n(Nd)=3-7. Adding a suitable amount of monomer, both Bd and isoprene(Ip) as seed in the preparation of catalyst can greatly increase the catalytic activity of the catalytic system, and Bd is found more effective. The polymerization rate increases rather rapidly and reaches the maximum within 10 min, then decreases slowly. The obtained \{\%p\%(Bd)\} has a molecule weight about 10 5-10 6 with cis-1,4 structure above 98% and gel content less than 6%.