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Kinetic modeling of ethylene polymerization with Cr-V bimetallic catalyst

LIU Bao1 TIAN Zhou2 ZHAO Ning1 LIU Boping1

(1.State Key Laboratory of Chemical Engineering, East China University of Science and Technology, Shanghai, China 200237)
(2.Key Laboratory of Advanced Control and Optimization for Chemical Processes, Ministry of Education, East China University of Science and Technology, Shanghai, China 200237)

【Abstract】Bimetallic catalyst has been a hot research topic as it can realize one-pot synthesis of polyethylene with bimodal molecular weight distribution (MWD). The kinetics of ethylene homopolymerization with a novel Cr-iV bimetallic catalyst and corresponding monometallic S-2 and iV catalysts were studied at various experimental conditions. The MWD deconvolution of polymers made by these catalysts showed interaction between Cr and V active centers in the Cr-iV bimetallic catalyst. The activity of Cr centers was reduced, while the activity of V centers was improved. The polymerization temperature almost did not change the mass fractions of polymers produced by two active centers. The simplified single-site kinetic model for ethylene homopolymerization was employed to describe the polymerization behaviors of Cr and V centers in Cr-iV bimetallic catalyst. The kinetic parameters of each active center were estimated by fitting the experimental results of polymerization rates with model prediction. Compared to monometallic catalyst, the Cr center in the Cr-iV catalyst had decreased chain propagation rate constant, which led to the reduction of polymerization activity, whereas the V center in the Cr-iV catalyst had decreased chain deactivation rate constant, which signified more stable and active V center.

【Keywords】 bimetallic catalyst; ethylene polymerization; kinetics; modeling;


【Funds】 National Natural Science Foundation of China (21404061, 21674036) Fundamental Research Funds for the Central Universities (222201714054)

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This Article


CN: 61-1369/U

Vol 20, No. 01, Pages 60-73

February 2020


Article Outline


  • Introduction
  • 1 Experiment
  • 2 Establishment of kinetic model for ethylene homopolymerization
  • 3 Results and discussion
  • 4 Conclusions
  • References