Introduction of titanium species into fluorine-modified SiO2- supported Cr-V bimetallic catalyst for ethylene polymerization and ethylene/1-hexene copolymerization

Document Type: Original research


State Key Lab of Chemical Engineering, East China University of Science and Technology, Meilong Road 130, Shanghai 200237, P. R. China


Chromium-vanadium (Cr-V) bimetallic catalysts are prepared by the introduction of vanadium into the Phillips catalyst which is one of the most significant industrial ethylene polymerization catalysts for tuning the Phillips catalyst performances and improving polyethylene properties. In the present work, titanium species were introduced into the fluorine-modified chromium-vanadium bimetallic catalysts (Cr-V-F) and the prepared catalysts were systematically explored. The element content results of multi-component catalysts showed that a competitive inhibition interaction existed between chromium and vanadium, whereas chromium was more preferable to attach to the Ti-SiO2 than vanadium. In addition, ethylene homopolymerization and ethylene/1-hexene copolymerization were carried out and examined with different catalysts. The introduction of titanium into fluorine-modified bimetallic catalysts enhanced the molecular weight (MW) and broadened the molecular weight distribution (MWD) of polyethylene. The MW of the titanium- and fluorine-modified bimetallic catalysts (Cr-V-F/Ti) firstly rose up and then dropped down with the increasing of the Al/Cr molar ratio. The Cr-V-F/Ti catalysts showed slightly depressed hydrogen response and incorporation of 1-hexene. The short-chain branch distribution (SCBD) results, which were characterized by TREF/SSA, showed that the introduction of the titanium species increased the SCB content in low MW fractions and decreased the SCB content in the high Mw fractions of ethylene/1-hexene copolymers obtained from (Cr-V-F/3Ti)600 in contrast to that from (Cr-V-F)600.


Main Subjects

  1. McDaniel MP (2010) A review of the Phillips supported chromium catalyst and its commercial use for ethylene polymerization. In: Handbook of transition metal polymerization catalysts, John Wiley & Sons, 123-606
  2. McDaniel MP (2008) Review of the Phillips chromium catalyst for ethylene polymerization. In: Handbook of heterogeneous catalysis, Wiley- VCH, 3733-3792
  3. Liu Z, He X, Cheng R, Eisen MS, Terano M, Liu B (2013) Chromium catalysts for ethylene polymerization and oligomerization. In: Advances in Chemical Engineering, Elsevier, 127–191
  4. McDaniel MP (1985) Supported chromium catalysts for ethylene polymerization. Adv Catal 33: 47-98
  5. Cheng R, Liu Z, Zhong L, He X, Qiu P, Terano M, Eisen MS, Scott SL, Liu B (2013) Phillips Cr/silica catalyst for ethylene polymerization. In: Polyolefins: 50 years after Ziegler and Natta I, Springer, 135-202
  6. Clark A, Hogan JP, Banks RL, Lanning WC (1956) Marlex catalyst systems. Ind Eng Chem 48: 1152-1155
  7. McDaniel MP (1983 Sep. 20) Polymerization process using chromium on a support treated with titanium polymer, US Patent 4,405,768
  8. Rebenstorf B, Sheng TC (1991) Influence of chromium concentration and addition of fluorine, titanium, or boron on the chromium species of the Phillips catalyst: A quantitative evaluation. Langmuir 7: 2160-2165
  9. Hawley GR (1981 Oct. 20) Titanium impregnated silica-chromium catalysts, US Patent 4,296,001
  10. Dreiling MJ (1983) The activation of the Phillips polymerization catalyst III. Promotion by titania. J Catal 82: 118-126231
  11. Cheng R, Xu C, Liu Z, Dong Q, He X, Fang Y, Terano M, Hu Y, Pullukat TJ, Liu B (2010) High-resolution spectroscopy (XPS, 1H mas solid-state NMR) and DFT investigations into Ti-modified Phillips CrOx/SiO2 catalysts. J Catal 273: 103- 115
  12. Zhong L, Liu Z, Cheng R, He X, Liu B (2013) Effect of fluorination of silica support on initiation of ethylene polymerization during induction period over Phillips catalyst. J Chem Ind Eng (China) 64: 539-546
  13. Hogan JP (1964 Apr. 21) Catalyst and process for producing olefin polymers, US Patent 3,130,188
  14. Nasser Jr. BED, Richard E. (1978 Dec. 19) Two stage activation of fluorided chromium-containing catalyst, US Patent 4,130,505
  15. McDaniel MP (1985 Oct. 15) Silica-titania cogel from two-step hydrolysis, US Patent 4,547,557
  16. Dwivedi S, Gujral SS, Taniike T, Terano M (2013) Chemical modification of silica support to improve the branching ability of Phillips catalyst. Pure Appl Chem 85: 533-541
  17. McDaniel MP, Johnson MM (1986) A comparison of chromium/silica and chromium/aluminum phosphate polymerization catalysts. I. Kinetics. J Catal 101: 446-457
  18. Zhang S, Dong Q, Cheng R, He X, Wang Q, Tang Y, Yu Y, Xie K, Da J, Liu B (2012) A novel SiO2- supported inorganic and organic hybrid chromium-based catalyst for ethylene polymerization. J Mol Catal A: Chem 358: 10-22
  19.  Zhang S, Cheng R, Dong Q, He X, Wang Q, Tang Y, Yu Y, Xie K, Da J, Terano M (2013) Ethylene/1-hexene copolymerization with a novel SiO2-supported inorganic and organic hybrid chromium-based catalyst. Macromol React Eng 7: 254-266
  20. Cheng R, Xue X, Liu W, Zhao N, He X, Liu Z, Liu B (2015) Novel SiO2-supported chromium oxide(Cr)/vanadium oxide(V) bimetallic catalysts for production of bimodal polyethylene. Macromol React Eng 9: 462-472
  21. Matta A, Zeng Y, Taniike T, Terano M (2012) Vanadium-modified bimetallic Phillips catalyst with high branching ability for ethylene polymerization. Macromol React Eng 6: 346- 350
  22. Zeng Y, Matta A, Dwivedi S, Taniike T, Terano M (2013) Development of a hetero-bimetallic Phillips-type catalyst for ethylene polymerization. Macromol React Eng 7: 668-673
  23. McDaniel MP (1982) The state of Cr(VI) on the Phillips polymerization catalyst. IV. Saturation coverage. J Catal 76: 37-47
  24. Bernd R (1991) The Phillips catalyst (Cr(VI)/ silica gel) modified by (NH4)2SiF6: Its influence on the chromium surface species. J Mol Catal 66: 59-71
  25. Levine IJ, Karol FJ (1976 Mar. 8) Preparation of low and medium density ethylene polymer in fluid reactor, US Patent 4,011,382
  26. Seger MR, Maciel GE, Chem. A (2004) Quantitative NMR analysis of sequence distributions in poly(ethylene-co-1-hexene). Anal Chem 76: 5734-5747
  27. Ma Y, Cheng R, Li J, Zhong L, Liu Z, He X, Liu B (2015) Effect of Mo-modification over Phillips CrOx/SiO2 catalyst for ethylene polymerization. J Organomet Chem 791: 311-321
  28. Zhao N, Cheng R, He X, Liu Z, Liu B (2014) A novel SiO2-supported Cr–V bimetallic catalyst making polyethylene and ethylene/1-hexene copolymers with bimodal molecular weight distribution. Macromol Chem Phys 215: 1753- 1766
  29. Müller AJ, Arnal ML (2005) Thermal fractionation of polymers. Prog Polym Sci 30: 559-603
  30. Tanem BS, Stori A (2001) Phase separation in melt blends of single-site linear and branched polyethylene. Polymer 42: 5689-5694
  31. Müller AJ, Hernández ZH, Arnal ML, Sánchez JJ (1997) Successive self-nucleation/annealing (SSA): A novel technique to study molecular segregation during crystallization. Polym Bull 39: 465-472
  32. Pullukat TJ, Hoff RE, Shida M (1980) A chemical study of thermally activated chromic titanate on silica ethylene polymerization catalysts. J Polym Sci A Polym Chem 18: 2857-2866
  33. Hoff RE, Pullukat TJ, Shida M (1981) Chromic titanate catalysts for high-melt-index polyethylene by the particle-form process. J Appl Polym Sci 26: 2927-2934
  34. Gao X, Wachs IE (2002) Molecular engineering of supported vanadium oxide catalysts through support modification. Top Catal 18: 243-250
  35. Gao X, Bare SR, Fierro J, Wachs IE (1999) Structural characteristics and reactivity/ reducibility properties of dispersed and bilayered V2O5/TiO2/SiO2 catalysts. J Phys Chem B 103: 618-629
  36. Mohamadnia Z, Ahmadi E, Nekoomanesh M, Ramazani A, Mobarakeh HS (2010) Effect of support structure on the activity of Cr/nanosilica catalysts and the morphology of prepared polyethylene. Polym Int 59: 945-953
  37. Ahmadi E, Mohamadnia Z, Rahimi S, Armanmehr MH, Razmjoo M, Heydari MH (2016) Phillips catalysts synthesized over various silica supports: Characterization and their catalytic evaluation in ethylene polymerization. Polyolefins J 3: 23-36
  38. McDaniel MP, Collins KS (2009) The influence of porosity on the Phillips Cr/silica catalyst 2. Polyethylene elasticity. J Polym Sci, Part A: Polym Chem 47: 845-865
  39. Marsden CE (1991) The influence of silica support on polymerisation catalyst performance. In: Preparation of catalysts V: Scientific bases for the preparation of heterogeneous catalysts, proceedings of the fifth international symposium, Elsevier, 215-227
  40. Liu B, Sindelar P, Fang Y, Hasebe K, Terano M (2005) Correlation of oxidation states of surface chromium species with ethylene polymerization activity for Phillips CrOx/SiO2 catalysts modified by Al-alkyl cocatalyst. J Mol Catal A-Chem 238: 142-150
  41. Xia W, Liu B, Fang Y, Hasebe K, Terano M (2006) Unique polymerization kinetics obtained from simultaneous interaction of Phillips Cr(VI) Ox/SiO2 catalyst with Al-alkyl cocatalyst and ethylene monomer. J Mol Catal A-Chem 256: 301-308
  42. Xia W, Tonosaki K, Taniike T, Terano M, Fujitani T, Liu B (2009) Copolymerization of ethylene and cyclopentene with the Phillips CrOx/SiO2 catalyst in the presence of an aluminum alkyl cocatalyst. J Appl Polym Sci 111: 1869-1877
  43. Xia W, Liu B, Fang Y, Fujitani T, Taniike T, Terano M (2010) Multinuclear solid-state NMR study of the coordinative nature of alkylaluminum cocatalyst on Phillips CrOx/SiO2 catalyst. Appl Catal, A-Gen 389: 186-194
  44. Krauss HL, Hanke B (1985) Surface compounds of transition metals. XXIX. Reaction of surface chromium(VI)/silica gel with aluminium alkyles: "Formation" of Phillips catalysts. Z Anorg Allg Chem 521: 111-121
  45. Krauss HL (1988) New results with Phillips systems: Surface compounds of transition metals, Part XXXII. J Mol Catal 46: 97-108
  46. Iwasawa Y, Sasaki Y, Ogasawara S (1982) Active fixed chromium catalysis for co-idation. Preparation and active structure of fixed Cr and catalysts. J Mol Catal 16: 27-41
  47. Hogan JP (1970) Ethylene polymerization catalysis over chromium oxide. J Polym Sci, Part Pol Chem 8: 2637-2652
  48. Soares JBP, Mckenna TFL (2013) Polyolefin Reaction Engineering. Weinheim, Germany, Wiley-VCH
  49. Ajjou JaN, Scott SL (2000) A kinetic study of ethylene and 1-hexene homo- and copolymerization catalyzed by a silica-supported Cr(IV) complex: Evidence for propagation by a migratory insertion mechanism. J Am Chem Soc 122: 8968-8976
  50. McDaniel MP, Schwerdtfeger ED, Jensen MD (2014) The “comonomer effect” on chromium polymerization catalysts. J Catal 314: 109-116
  51. Clark A (1970) Olefin polymerization on supported chromium oxide catalysts. Cat Rev 3: 145-173
  52. Rangwala HA, Dalla Lana IG, Szymura JA, Fiedorow RM (1996) Copolymerization of ethylene and 1-butene using a Cr-silica catalyst in a slurry reactor. J Polym Sci Pol Chem 34: 3379-3387
  53. Lorenzo AT, Arnal ML, Müller AJ, Fierro ABD, Abetz V (2006) High speed SSA thermal fractionation and limitations to the determination of lamellar sizes and their distributions. Macromol Chem Phys 207: 39-49