MoO_2Br_2体系催化合成1,2—聚丁二烯——催化活性和聚合物分子量

SYNTHESIS OF 1, 2—POLYBUTADIENE WITH MoO_2Br_2 CATALYST SYSTEM CATALYSTC ACTIVITY AND MOLECULAR WEICHT OF POLYMER

催化体系活性的高低与主助催化剂(Mo与AL)及单体(D真)的加料方式有关,以Bd-Al-Mo的加料顺序为最佳。在固定Mo/Bd=7.0×10^(-5),与MoCl_4、MoCl_6和MoO_2Br_2体系相比,MoO_2Br_2体系催化活性最高,催化体系中Br代Cl真后,Mn和[η]的时间变化率,△Mn/△t和△[η]/△t,增大约1.5倍,Mn较其他钼系高约2倍,1,2—键节含量约98％,亦高于含Cl帽体系。

The catalytic activity of MoO_2Br_2 system for the synthesis of 1, 2—polybutadiene depended close ly on the order of main catalyst (Mo), cocatalyst (Al) a nd monomer (Br) mixing each other, the mixing order of Bd—Al—Mo was the most suitable for the need of high activity, and as well as on the mole ratio of Al/Mo and Mo/Bd, Under the condition of Mo/Bd mole ratio equal to 7.0×10^(-5), the catalytic activity of MoO_2Br_2 system was highter than in other molybdenum systems, such as MoCl_4, MoCl_5 and MoO_2Cl_2. When Cl component in the main catalyst was exchanged with Br, the time rates of change of Mn, △Mn/△t and △η/△t were about increased by a factor 1.5, and Mn was about two times greater than other molybdenum catalyst contained Cl. The content of 1, 2-chain unit in the system, being about 98％, was higher than in other systems.