Study on the decomposition mechanism of supercritical ethylene during ultra-high pressure polymerization process

Chen Yao; Zhang Zhichen; Zhu Yunfeng; Chen Haowen; Song Yifan; Zhang Ruiyi; Shi Xiaogang; Sun Bing; Xu Wei

doi:10.1016/j.cjche.2025.09.031

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Study on the decomposition mechanism of supercritical ethylene during ultra-high pressure polymerization process

Updated：2026-05-14

- Study on the decomposition mechanism of supercritical ethylene during ultra-high pressure polymerization process
- Chinese Journal of Chemical Engineering Vol. 90, Issue 2, Pages: 146-156(2026)
- Affiliations：
  
  State Key Laboratory of Chemical Safety, Qingdao 266000, China
  SINOPEC Research Institute of Safety Engineering Co., Ltd. Qingdao 266000, China
  National Registration Center for Chemicals, Ministry of Emergency Management, Qingdao 266000, China
  College of Chemical Engineering and Environment, China University of Petroleum (Beijing), Beijing 102249, China
- Author bio：
  
  These authors contributed equally to this work.
  Corresponding authors. E-mail addresses: sunb.qday@sinopec.com (B. Sun)
  Corresponding authors. xuw.qday@sinopec.com (W.Xu).
- Funds：
- DOI：10.1016/j.cjche.2025.09.031
  CLC：
- Received：27 June 2025，
  
  Revised：2025-09-28，
  
  Accepted：28 September 2025，
  
  Online First：27 November 2025，
  
  Published：2026-02
- Accepted：
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Chen Yao, Zhang Zhichen, Zhu Yunfeng, et al. Study on the decomposition mechanism of supercritical ethylene during ultra-high pressure polymerization process[J]. Chinese Journal of Chemical Engineering, 2026, 90(2): 146-156.
DOI：

Chen Yao, Zhang Zhichen, Zhu Yunfeng, et al. Study on the decomposition mechanism of supercritical ethylene during ultra-high pressure polymerization process[J]. Chinese Journal of Chemical Engineering, 2026, 90(2): 146-156. DOI： 10.1016/j.cjche.2025.09.031.

摘要

Abstract

In the production of low density polyethylene (LDPE)

the presence of oxygen may induce the decomposition of supercritical ethylene

thereby affecting the stability of equipment operation and potentially leading to safety hazards. This study investigated the inducing and promoting effects of oxygen on the runaway decomposition of supercritical ethylene. The reaction mechanism of oxygen-induced supercritical ethylene was explored through ReaxFF molecular dynamics

simulation

and the reaction network was systematically constructed. It was found that the minimum oxygen concentration required to initiate ethylene decomposition at 240℃ and 240 MPa was 0.0042% (mass). The coupling of oxygen and ethylene to form the intermediate C

O· promoted the cleavage of the C—C bond in ethylene. Under the condition of oxygen absence

ethylene mainly underwent polymerization reactions. As the oxygen concentration increased

unstable intermediates such as C

O· were generated

and the dominant reaction pathway of ethylene shifted from polymerization to decomposition. This study provided a theoretical basis for understanding the oxygen induced supercritical ethylene decomposition in low density polyethylene process.

关键词

Keywords

references

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