Ethylene polymerization catalyzed by rare earth calixarene catalytic system

Eleven calixarene rare earth complexes were prepared by alcohol–phenol exchange reaction of rare earth isopropoxides with calixarenes in toluene. These rare earth calixarene complexes combined with Al(iBu)3 were found for the first time to be effective homogeneous catalysts to polymerize ethylene. The effects of Al/Nd molar ratio and reaction temperature on the polymerization were investigated. The catalytic activity of calixarene neodymium system is 39.5 kg PE/mol Nd h giving polyethylene with viscosity average molecular weight of 93.1×104 under the following conditions: [Nd]=1×10−3 mol/l−1, Al/Nd=15, T=80°C, time=0.5 h, ethylene pressure=1.2 MPa. AlBu2H, AlEt3 can be used instead of Al(iBu)3 to form effective catalyst with calixarene neodymium for ethylene polymerization.