Chinese Journal of Polymer Science

, Volume 37, Issue 10, pp 1023–1030 | Cite as

Deactivation Effect Caused by Catalyst-Cocatalyst Pre-contact in Propylene Polymerization with MgCl2-supported Ziegler-Natta Catalyst

  • Zhen Zhang
  • Bai-Yu Jiang
  • Biao Zhang
  • Zhi-Sheng Fu
  • Zhi-Qiang FanEmail author


Propylene slurry polymerization with a MgCl2-supported Ziegler-Natta catalyst containing internal electron donor was conducted after different durations of pre-contact of the catalyst with triethylaluminum cocatalyst. The number of active centers ([C*]/[Ti]) was determined by quenching the polymerization with 2-thiophenecarbonyl chloride and measuring sulfur content in the polymer. The pre-contact treatment caused selective deactivation of a part of active centers with low stereoselectivity and much lower activity in the initial stage of polymerization as compared with the polymerization run without the pre-contact stage. The active center concentration and polymerization activity decreased with prolonging of the pre-contact stage. The proportion of stereoselective active centers was increased by prolonging the pre-contact stage, so the isotacticity of produced polypropylene was enhanced. Release of active centers through catalyst particle fragmentation was significantly retarded, and the polymerization rate curve changed from decay type to induction type by the precontact treatment. In the induction period both non-stereoselective and stereoselective active centers were released and activated, resulting in gradual reduction of the polymer’s isotacticity in the first 5–10 min of polymerization. Selective deactivation of non-stereoselective active centers also took place in propylene polymerization using the catalyst without pre-contacting with the cocatalyst. In this case, the polymerization rate decayed with time after a short induction period of 2–5 min. Over reduction of the active center precursors with low stereoselectivity by triethylaluminum was considered as the reason for their deactivation during the pre-contact or the polymerization processes.


Propylene Polymerization Supported Ziegler-Natta catalyst Cocatalyst Pre-contact 


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.



This work was financially supported by the National Natural Science Foundation of China (No. 51773178).


  1. 1.
    Kashiwa, N.; Yoshitake, J. The influence of the valence state of titanium in MgCl2-supported titanium catalysts on olefin polymerization. Makromol. Chem. 1984, 185, 1133–1138.CrossRefGoogle Scholar
  2. 2.
    Busico, V.; Corradini, P.; Ferraro, A.; Proto, A. Polymerization of propene in the presence of MgCl2-supported Ziegler-Natta catalysts, 3. Catalyst deactivation. Makromol. Chem. 1986, 181, 1125–1130.CrossRefGoogle Scholar
  3. 3.
    Yang, C. B.; Hsu, C. C. Effect of catalyst aging on catalyst activity and stereospecificity for MgClz/ethyl benzoate or dioctyl phthalate/TiCl4-triethylaluminium for propene polymerization. Macromol. Rapid Commun. 1995, 16, 311–316.CrossRefGoogle Scholar
  4. 4.
    Mori, H.; Hasebel, K.; Terano, M. Variation in oxidation state of titanium species on MgCl2-supported Ziegler catalyst and its correlation with kinetic behavior for propylene polymerization. Polymer 1999, 40, 1389–1394.CrossRefGoogle Scholar
  5. 5.
    Potapov, A. G.; Terskikh, V. V.; Zakharov, V. A.; Bukatov, G. D. 27Al NMR MAS study of the surface Al complexes formed in reaction of organoaluminium compounds with supported TiCl4/MgCl2 catalyst. J. Mol. Catal. A: Chem. 1999, 145, 147–152.CrossRefGoogle Scholar
  6. 6.
    Potapov, A. G.; Terskikh, V. V.; Bukatov, G. D.; Zakharov, V. A. 27Al MAS NMR study of the interaction of supported Ziegler-Natta catalysts with organoaluminium co-catalyst in the presence of donors. J. Mol. Catal. A: Chem. 2000, 158, 457–460.CrossRefGoogle Scholar
  7. 7.
    Shimizu, F.; Pater, J. T. M.; Van Swaaij, W. P. M.; Weickert, G. Kinetic study of a highly active MgCl2-supported Ziegler-Natta catalyst in liquid pool propylene polymerization. II. The influence of alkyl aluminum and alkoxysilane on catalyst activation and deactivation. J. Appl. Polym. Sci. 2002, 83, 2669–2679.CrossRefGoogle Scholar
  8. 7.
    Fregonese, D.; Mortara, S.; Bresadola, S. Ziegler-Natta MgCl2-supported catalysts: Relationship between titanium oxidation states distribution and activity in olefin polymerization. J. Mol. Catal. A: Chem. 2001, 172, 89–95.CrossRefGoogle Scholar
  9. 9.
    Liu, B. P.; Nitta, T.; Nakatani, H.; Terano, M. Specific roles of Al-alkyl cocatalyst in the origin of isospecificity of active sites on donor-free TiCl4/MgCl2 Ziegler-Natta catalyst. Macromol. Chem. Phys. 2002, 203, 2412–2421.CrossRefGoogle Scholar
  10. 10.
    Nitta, T.; Liu, B. P.; Nakatani, H.; Terano, M. Formation, deactivation and transformation of stereospecific active sites on TiCl4/dibutylphthalate/Mg(OEt)2 catalyst induced by short time reaction with Al-alkyl cocatalyst. J. Mol. Catal. A: Chem. 2002, 180, 25–34.CrossRefGoogle Scholar
  11. 11.
    Murayama, N.; Liu, B. P.; Nakatani, H.; Terano, M. Plausible guard effect on the active sites of heterogeneous Ziegler-Natta catalyst by coordinating monomers and growing polymer chains in the initial stage of propene polymerization. Polym. Int. 2004, 53, 723–727.CrossRefGoogle Scholar
  12. 12.
    Al-arifi, S. N. Propylene polymerization using MgCl2/ethylbenzoate/TiCl4 catalyst: Determination of titanium oxidation states. J. Appl. Polym. Sci. 2004, 93, 56–62.CrossRefGoogle Scholar
  13. 13.
    Chumachenko, N. N.; Bukatov, G. D.; Sergeev, S. A.; Zakharov, V. A. State of titanium in supported titanium-magnesium catalysts for propylene polymerization. Kinet. Catal. 2011, 52, 234–241.CrossRefGoogle Scholar
  14. 14.
    Trischler, H.; Schofberger, W.; Paulik, C. Influence of alkylaluminum co-catalysts on TiCl4 transalkylation and formation of active centers C* in Ziegler-Natta catalysts. Macromol. React. Eng. 2013, 7, 146–154.CrossRefGoogle Scholar
  15. 15.
    Tan, N.; Yu, L. Q.; Tan, Z.; Mao, B. Q. Kinetics of the propylene polymerization with prepolymerization at high temperature using Ziegler-Natta catalyst. J. Appl. Polym. Sci. 2015, 41816.Google Scholar
  16. 16.
    Shen, X. R.; Hu, J.; Fu, Z. S.; Lou, J. Q.; Fan, Z. Q. Counting the number of active centers in MgCl2-supported Ziegler-Natta catalysts by quenching with 2-thiophenecarbonyl chloride and study on the initial kinetics of propylene polymerization. Catal. Commun. 2013, 30, 66–69.CrossRefGoogle Scholar
  17. 17.
    Shen, X. R.; Fu, Z. S.; Hu, J.; Wang, Q.; Fan, Z. Q. Mechanism of propylene polymerization with MgCl2-supported Ziegler-Natta catalysts based on counting of active centers: The role of external electron donor. J. Phys. Chem. C 2013, 117, 15174–15182.CrossRefGoogle Scholar
  18. 18.
    Yang, H. R.; Zhang, L. T.; Fu, Z. S.; Fan, Z. Q. Comonomer effects in copolymerization of ethylene and 1-hexene with MgCl2-supported Ziegler-Natta catalysts: New evidences from active center concentration and molecular weight distribution. J. Appl. Polym. Sci. 2015, 132, 41264.Google Scholar
  19. 19.
    Yang, H. R.; Zhang, L. T.; Fu, Z. S.; Fan, Z. Q. Effects of alkylaluminum as cocatalyst on the active center distribution of 1-hexene polymerization with MgCl2-supported Ziegler-Natta catalysts. Catal. Commun. 2015, 62, 104–106.CrossRefGoogle Scholar
  20. 20.
    Guo, Y. T.; Zhang, Z.; Guo, W. Q.; Khan, A.; Fu, Z. S.; Xu, J. T.; Fan, Z. Q. Kinetics and mechanism of metallocene-catalyzed olefin polymerization: Comparison of ethylene, propylene homopolymerizations, and their copolymerization. J. Polym. Sci., Part A: Polym. Chem. 2017, 55, 867–875.CrossRefGoogle Scholar
  21. 21.
    Khan, A.; Guo, Y. T.; Fu, Z. S.; Fan, Z. Q. Kinetics of shortduration ethylene polymerization with MgCl2-supported Ziegler-Natta catalyst: Two-stage initiation evidenced by changes in active center concentration. J. Appl. Polym. Sci. 2017, 134, 45187.CrossRefGoogle Scholar
  22. 22.
    Jiang, B. Y.; Weng, Y. H.; Zhang, S. J.; Zhang, Z.; Fu, Z. S.; Fan, Z. Q. Kinetics and mechanism of ethylene polymerization with TiCl4/MgCl2 model catalysts: Effects of titanium content. J. Catal. 2018, 360, 57–65.CrossRefGoogle Scholar
  23. 23.
    Khan, A.; Guo, Y. T.; Zhang, Z.; Ali, A.; Fu, Z. S.; Fan, Z. Q. Kinetics of short-duration ethylene-propylene copolymerization with MgCl2-supported Ziegler-Natta catalyst: Differentiation of active centers on the external and internal surfaces of the catalyst particles. J. Appl. Polym. Sci. 2018, 135, 46030.CrossRefGoogle Scholar
  24. 24.
    Jiang, B. Y.; Liu, X. Y.; Weng, Y. H.; Fu, Z. S.; He, A. H.; Fan, Z. Q. Mechanistic study on comonomer effect in ethylene/1-hexene copolymerization with TiCl4/MgCl2 model Ziegler-Natta catalysts. J. Catal. 2019, 369, 324–334.CrossRefGoogle Scholar
  25. 25.
    Giannini, U. Polymerization of olefins with high activity catalysts. Makromol. Chem., Suppl. 1981, 5, 216–229.CrossRefGoogle Scholar
  26. 26.
    Tait, P. J. T.; Wang S. M. Studies on the polymerization of propylene using high activity Ziegler-Natta catalysts. 1: Kinetic models for rate decay in Ziegler-Natta polymerization. British Polymer Journal 1988, 20, 499–508.CrossRefGoogle Scholar
  27. 27.
    Jiang, B. Y.; He, F.; Yang, P. J.; Zhang, Z.; Weng, Y. H.; Cheng, Z. M.; Fu, Z. S.; Fan, Z. Q. Enhancing stereoselectivity of propylene polymerization with MgCl2-supported Ziegler-Natta catalysts by electron donor: Strong effects of titanium dispersion state. Catal. Commun. 2019, 121, 38–42.CrossRefGoogle Scholar
  28. 28.
    Weng, Y. H.; Jiang, B. Y.; Fu, Z. S.; Fan, Z. Q. Mechanism of internal and external electron donor effects on propylene polymerization with MgCl2-supported Ziegler-Natta catalyst: New evidences based on active center counting. J. Appl. Polym. Sci. 2018, 135, 46605.CrossRefGoogle Scholar
  29. 29.
    Kakugo, M.; Miyatake, T.; Naito, Y.; Mizunuma, K. Microtacticity distribution of polypropylenes prepared with heterogeneous Ziegler-Natta catalysts. Macromolecules 1988, 21, 314–319.CrossRefGoogle Scholar
  30. 30.
    Xu, J. T.; Feng, L. X.; Yang, S. L.; Yang, Y. Q.; Kong, X. M. Influence of electron donors on the tacticity and the composition distribution of propylene-butene copolymers produced by supported Ziegler-Natta catalysts. Macromolecules 1997, 30, 7655–7660.CrossRefGoogle Scholar
  31. 31.
    Xu, J. T.; Feng, L. X.; Yang, S. L.; Yang, Y. Q.; Kong, X. M. Temperature rising elution fractionation of polypropylene produced by heterogeneous Ziegler-Natta catalysts. Eur. Polym. J. 1998, 34, 431–434.CrossRefGoogle Scholar
  32. 32.
    Tu, S. T.; Fu, Z. S.; Fan, Z. Q. Influence of cocatalyst on the structure and properties of polypropylene/poly(ethylene-co-propylene) in-reactor alloys prepared by MgCl2/TiCl4/diester type Ziegler-Natta catalyst. J. Appl. Polym. Sci. 2012, 124, 5154–5164.CrossRefGoogle Scholar
  33. 33.
    Correa, A.; Credendino, R.; Pater, J. T. M.; Morini, G.; Cavallo, L. Theoretical investigation of active sites at the corners of MgCl2 crystallites in supported Ziegler-Natta catalysts. Macromolecules 2012, 45, 3695–3701.CrossRefGoogle Scholar
  34. 34.
    Credendino, R.; Liguori, D.; Fan, Z. Q.; Morini, G.; Cavallo, L. Toward a unified model explaining heterogeneous Ziegler-Natta catalysis. ACS Catal. 2015, 5, 5431–5435.CrossRefGoogle Scholar
  35. 35.
    Dwivedi, S., Taniike, T.; Terano, M. Understanding the chemical and physical transformations of a Ziegler-Natta catalyst at the initial stage of polymerization kinetics: The key role of alkylaluminum in the catalyst activation process. Macromol. Chem. Phys. 2014, 215, 1698–1706.CrossRefGoogle Scholar
  36. 36.
    Yang, P. J.; Fu, Z. S.; Fan, Z. Q. 1-Hexene polymerization with supported Ziegler-Natta catalyst: Correlation between catalyst particle disintegration and active center distribution. Mol. Catal. 2018, 447C, 13–20.CrossRefGoogle Scholar

Copyright information

© Chinese Chemical Society Institute of Chemistry, Chinese Academy of Sciences Springer-Verlag GmbH Germany, part of Springer Nature 2019

Authors and Affiliations

  • Zhen Zhang
    • 1
  • Bai-Yu Jiang
    • 1
  • Biao Zhang
    • 1
  • Zhi-Sheng Fu
    • 1
  • Zhi-Qiang Fan
    • 1
    Email author
  1. 1.Ministry of Education Key Laboratory of Macromolecular Synthesis and Functionalization, Department of Polymer Science and EngineeringZhejiang UniversityHangzhouChina

Personalised recommendations