Determination of kinetic parameters for ethylene polymerization (with and without hydrogen) by Ziegler-Natta catalyst

Document Type : Original research

Authors

Polymer Research Group, National Petrochemical Research and Technology Company, Tehran, 1497713115, Iran

Abstract

In this study, slurry polymerization kinetics of ethylene with TiCl4/Mg(OEt)2/AlR3 Ziegler-Natta catalysts in various conditions using the model of sum square error (SSE) (method I) and model of least square error (LSE) (Method II) was investigated. For this purpose the molecular weight distributions of the samples were deconvoluted to the minimum number of Flory type distributions where each represents a different active center type of Ziegler-Natta catalyst. The first method used to determine the leading apparent polymerization kinetic constants for each site in absence of hydrogen by simultaneously fitting the instantaneous polymerization rate, cumulative polymer yield, and molecular weight distribution measured for various samples with various conditions. Second method was used to determine all kinetics parameters such as initiation, propagation, termination and transfer to monomer reaction in absence and also in the presence of hydrogen. For the later, transfer to hydrogen also determined. The results showed that this simulation package is a powerful tool for design and scale up this kind of processes.

Keywords


  1. Andrady AL (2003) Plastics and the Environ­ment. John Wiley & Sons
  2. Peacock A (2000) Handbook of polyethylene: structures: properties, and applications. CRC Press
  3. Jozaghkar MR, Jahani Y, Arabi H, Ziaee F (2018), Preparation and assessment of phase morphology, rheological properties and thermal behavior of low density polyethylene / polyhex­ene-1 blends. Polym Plast Technol Eng 57: 757- 765
  4. Ghafelebashi Z. SM , Mortazavi SMM, Najafi M, Haddadi-Asl V (2012) Effects of Tempera­ture and Cocatalyst Concentration on the Num­ber of Active Sites in a TiCl4/Mg(OEt)2 Catalyst for Ethylene Polymerization. J Pet Sci Technol 2: 12–16
  5. Skomorokhov VB, Zakharov VA, Kirillov VA (1996) Investigation of the kinetics of ethylene polymerization with supported titanium-magne­sium catalysts of various composition. Macro­mol Chem Phys 197: 1615–1631
  6. Barabanov AA, Zakharov VA, Sukulova VV (2015) Kinetic evidences for reversible transfor­mations of active centers in ethylene polymer­ization by titanium–magnesium catalyst: Effect of the polymerization temperature. J Organomet Chem 79: 292–298
  7. Zacca JJ (1995) Distributed parameter modelling of the polymerization of olefins in chemical reac­tors. PhD Thesis, Wisconsin University, Madison
  8. Casalini T, Visscher F, Janssen E, Bertola F, Stor­ti G, Morbidelli M (2017) Modeling of Polyole­fin Polymerization in Semibatch Slurry Reactors: Experiments and Simulations. Macromol React Eng 11: 1600036
  9. Salami-Kalajahi M, Haddadi-Asl V, Najafi M, Ghafelebashi Zarand SM (2008) Investigation of ethylene polymerization kinetics over Ziegler- Natta catalysts: Employing moment equation modeling to study the effect of different active centers on homopolymerization kinetics. E-Poly­mers 8: DOI: 10.1515/epoly.2008.8.1.29
  10. Kim JH, Kim I, Woo SI (1991) Computer simu­lation study of ethylene polymerization rate pro­file catalyzed over highly active Ziegler-Natta catalysts. Ind Eng Chem Res 30: 2074–2079
  11. Hutchinson RA, Chen CM, Ray WH (1992) Po­lymerization of olefins through heterogeneous catalysis X: Modeling of particle growth and morphology J Appl Polym Sci 44: 1389–1414
  12. Gemoets F, Zhang M, Karjala TW, Kolthammer BWS (2010) Kinetic study of ethylene homopo­lymerization in slurry using a Ziegler-Natta cata­lyst. Macromol React Eng 4: 109–122
  13. Alshaiban A, Soares JBP (2012) Effect of hy­drogen and external donor on propylene polym­erization kinetics with a 4th-generation Ziegler- Natta catalyst, Macromol React Eng 6: 265–274
  14. Matsko MA, Echevskaya LG, Zakharov VA, Nikolaeva MI, Mikenas TB, Vanina MP (2009) Study of multi-site nature of supported Ziegler- Natta catalysts in ethylene-hexene-1 copolymer­ization. Macromol Symp 282: 157–166
  15. Zheng ZW, Shi DP, Su PL, Luo ZH, Li XJ (2010) Steady-state and dynamic modeling of the basell multireactor olefin polymerization process. Ind Eng Chem Res 50: 322–331
  16. Kissin YV, Mink RI, Nowlin TE (1999) Ethyl­ene polymerization reactions with Ziegler–Natta catalysts. I. Ethylene polymerization kinetics and kinetic mechanism. J Polym Sci Pol Chem 37: 4255–4272
  17. Kissin YV (1995) Molecular weight distributions of linear polymers: detailed analysis from GPC data. J Polym Sci Pol Chem 33: 227–237
  18. Soares JBP (1994) Dynamic mathematical mod­elling of polymerization of olefins using hetero­geneous and homogeneous Ziegler-Natta cata­lysts. PhD Thesis, McMaster University, Ontario
  19. Chen K, Mehdiabadi S, Liu B, Soares JBP (2016) Estimation of apparent kinetic constants of indi­vidual site types for the polymerization of eth­ylene and α-olefins with Ziegler–Natta catalysts. Macromol React Eng 10: 551-556
  20. Flory PJ (1937) The mechanism of vinyl polym­erizations1. J Am Chem Soc 59: 241–253
  21. Kissin YV, Mink RI, Nowlin TE, Brandolini AJ (1999) Kinetics and mechanism of ethylene ho­mopolymerization and copolymerization reac­tions with heterogeneous Ti-based Ziegler–Natta catalysts. Top Catal 7: 69–88
  22. Kissin YV (1995) Kinetics of olefin copolymer­ization with heterogeneous Ziegler-Natta cata­lysts. Macromol Symp 89: 113–123
  23. Orbey H, Bokis CP, Chen C (1998) Equation of state modeling of phase equilibrium in the low-density polyethylene process: The Sanchez−La­Combe, statistical associating fluid theory, and polymer-Soave−Redlich−Kwong Equations of State. Ind Eng Chem Res 37: 4481–4491
  24. Kissin YV (2001) Main kinetic features of eth­ylene polymerization reactions with heteroge­neous Ziegler–Natta catalysts in the light of a multicenter reaction mechanism. J Polym Sci Pol Chem 39: 1681–1695
Volume 7, Issue 2
July 2020
Pages 121-130
  • Receive Date: 26 April 2020
  • Revise Date: 30 June 2020
  • Accept Date: 12 July 2020
  • First Publish Date: 12 July 2020