LOW PRESSURE PROCESS FOR PREPARING LOW-DENSITY POLYETHYLENE

Disclosed are catalyst systems, processes for making the catalyst systems, and processes for polymerizing at least one olefin monomer comprising ethylene to form a low-density polyethylene (LDPE). Thepolymerization process uses a catalyst system that can include: at least one diimine complex having the formula I:, wherein M is Ni, Pd, or Pt; a first activator such as an organoaluminum compound; and a second activator including a solid oxide chemically-treated with an electron withdrawing anion, such as fluoride silica-alumina. It was discovered that such the complexes could be activated in amanner to provide an active catalyst system that polymerized ethylene to form a low-density polyethylene (LDPE). 公开了催化剂系统，制备催化剂系统的方法，和聚合至少种包含乙烯的烯烃单体以形成低密度聚乙烯(LDPE)的方法。聚合方法使用催化剂系统，其可包括：至少种具有式I的二亚胺络合物，其中M是Ni、Pd或Pt；第活化剂，如有机铝化合物；和第二活化剂，其包括用吸电子阴离子化学处理的固体氧化物，如氟化二氧化硅-氧化铝。发现这种络合物可以以提供聚合乙烯以形成低密度聚乙烯(LDPE)的活性催化剂系统的方式被活化。