Mechanistic Study on the Dominant Promotion Effect of Al-/Ti-/Zr-modifications over the VO<sub><italic style="font-style: italic">x</italic></sub>/SiO<sub>2</sub> UHMWPE Catalysts

Yu-Long Jin; Lin Liu; Yu-Jie Wang; Zhen Liu; Bo-Ping Liu

doi:10.1007/s10118-019-2295-z

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Mechanistic Study on the Dominant Promotion Effect of Al-/Ti-/Zr-modifications over the VO_x/SiO₂ UHMWPE Catalysts

ARTICLE | Updated：2021-02-18

- Mechanistic Study on the Dominant Promotion Effect of Al-/Ti-/Zr-modifications over the VO_x/SiO₂ UHMWPE Catalysts
- Chinese Journal of Polymer Science Vol. 37, Issue 10, Pages: 995-1004(2019)
- Affiliations：
  
  a.College of Materials and Energy, South China Agricultural University, Guangzhou 510642, China
  b.School of Chemical Engineering, East China University of Science and Technology, Shanghai 200237, China
- Author bio：
  
  boping@scau.edu.cn
- Funds：
- DOI：10.1007/s10118-019-2295-z
  CLC：
- Received：30 March 2019，
  
  Revised：2019-5-13，
  
  Accepted：16 May 2019，
  
  Online First：02 July 2019，
  
  Published：2019-10
- Accepted：
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Citation: Jin, Y. L.; Liu, L.; Wang, Y. J.; Liu, Z.; Liu, B. P. Mechanistic study on the dominant promotion effect of Al-/Ti-/Zr-modifications over the VO_x/SiO₂ UHMWPE catalysts. Chinese J. Polym. Sci. 2019, 37, 995–1004 DOI: 10.1007/s10118-019-2295-z.

Yu-Long Jin, Lin Liu, Yu-Jie Wang, et al. Mechanistic Study on the Dominant Promotion Effect of Al-/Ti-/Zr-modifications over the VO_x/SiO₂ UHMWPE Catalysts[J]. Chinese Journal of Polymer Science, 2019, 37(10): 995-1004. DOI: 10.1007/s10118-019-2295-z.
Citation: Jin, Y. L.; Liu, L.; Wang, Y. J.; Liu, Z.; Liu, B. P. Mechanistic study on the dominant promotion effect of Al-/Ti-/Zr-modifications over the VO_x/SiO₂ UHMWPE catalysts. Chinese J. Polym. Sci. 2019, 37, 995–1004 DOI: 10.1007/s10118-019-2295-z. DOI：

Yu-Long Jin, Lin Liu, Yu-Jie Wang, et al. Mechanistic Study on the Dominant Promotion Effect of Al-/Ti-/Zr-modifications over the VO_x/SiO₂ UHMWPE Catalysts[J]. Chinese Journal of Polymer Science, 2019, 37(10): 995-1004. DOI: 10.1007/s10118-019-2295-z. DOI：

摘要

Abstract

Recently

we reported the first VO

/SiO

ethylene polymerization catalyst for making Cl-free UHMWPE

and found the dominant promotion effects of Al-/Ti-/Zr-modifications over this catalyst system (Macromol. Chem. Phys. 2017

218

1600443). In this work

density functional theory is applied to investigate the underlying mechanism of this remarkable promotion effect of Al-/Ti-/Zr-modifications on a molecular and atomic level. The cluster model with V(III) is found to be the most possible active site due to its lowest overall energy barrier for monomer insertion

though the process of C

coordination and the subsequent formation of transition state are most energy favored for V(II) species. By modifying one of or both V―O―Si in the active model with V―O―M (M ＝ Al

or Zr)

the energy barrier for the binding of the upcoming C

gets lower (particularly for Al- and Zr-modified catalysts)

and the transition state also becomes more stable. Generally

the insertion process of C

gets easier after support Al-/Ti-/Zr-modifications. This dominant promotion effect is partially ascribed to the more enriched positive charge distribution on or nearby the V center

and the narrower energy gap between the LUMO of model catalysts and the HOMO of C

for these modified catalysts also contributes much. In addition

the decreased steric hindrance around the V center should be taken into account for the modified models as well. Furthermore

the Brønsted acidity of the catalysts is investigated by introducing a pendent hydroxyl group to the model catalysts

which has a close contact with the V center. Similar promotion effect of support modification by Al

and Zr could still be observed.

关键词

Keywords

references

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⁰

Mechanistic Study on the Dominant Promotion Effect of Al-/Ti-/Zr-modifications over the VOx/SiO2 UHMWPE Catalysts

DOI：10.1007/s10118-019-2295-z

摘要

Abstract

关键词

Keywords

references

Mechanistic Study on the Dominant Promotion Effect of Al-/Ti-/Zr-modifications over the VO_x/SiO₂ UHMWPE Catalysts