丙烯聚合TiCl_4/MgCl_2催化剂制备过程中原位生成邻苯二甲酸二正丁酯的研究

In Situ Synthesis of Di-n-Butyl-Phthalate During Preparation of TiCl_4/MgCl_2 Catalysts for Propylene Polymerization

采用红外光谱、紫外-可见光谱、气相色谱和色谱-质谱联用等技术对不同条件下磷酸三丁酯和环氧氯丙烷溶解体系制备的丙烯聚合TiCl4/MgCl2催化剂的结构进行了表征。表征结果显示,在TiCl4/MgCl2催化剂的制备过程中,原位生成了少量的内给电子体邻苯二甲酸二正丁酯(DNBP)。TiCl4/MgCl2催化剂的丙烯淤浆聚合结果表明,在该催化剂体系中原位生成的少量DNBP对其催化性能产生一定的影响,通过降低无规活性中心的含量来提高TiCl4/MgCl2催化剂的定向能力;外加大量的DNBP,既降低了TiCl4/MgCl2催化剂中无规活性中心的含量,又使TiCl4/MgCl2催化剂的定向能力进一步提高。

TiCl4/MgCl2 catalysts used in propylene slurry polymerization were prepared in tdbutyl phosphate and epoxy chloropropane solution system under different conditions, and characterized by means of IR, UV-Vis, GC and GC-MS. It was found that a small amount of di-n-butyl-phthalate （DNBP） was produced in-situ by chemical reactions in the system and acted as internal donor in polymerization. It can influence catalyst performance in propylene polymerization and enhance stereospecificity of the catalyst by reducing atactic active sites in the catalyst. Additional input of DNBP not only decreases amount of atactic active sites, but also raises stereospecificity of catalysts.