Dissolution Mechanism of Nonionic Polyether Surfactants in Supercritical CO2

Author

Ning Xu
Yanling Wang
Baojun Bai, Missouri University of Science and TechnologyFollow
Shizhang Cui
Zan Gao
Yu Zhang
Di Li
Wenjing Shi
Wenhui Ding
Peixu Ma

Abstract

Polyoxyethylene ether is an efficient CO₂-philic compound with significant potential applications in CO₂ flooding, which requires CO₂-philic surfactants with high solubility in supercritical CO₂ (scCO₂). This study elucidates the molecular and atomic-level dissolution mechanism of the fatty alcohol polyoxyethylene ether (AEO) in scCO₂ by combining phase-behavior experiments and molecular dynamics simulations. The solubility of AEO in scCO₂ is measured using a semiconductor laser. AEO containing three polyoxyethylene (EO) groups exhibited the highest solubility in scCO₂.The solubility of AEO in scCO₂ decreased with an increase in the number of EO groups. Molecular dynamics simulations reveal that the interaction force between the AEO and CO₂ is predominantly determined by van der Waals forces, which account for 70% of the total interaction force, while the interactions between the alkyl chain, EO group, and CO₂ in AEO are primarily driven by Lewis acid–base (LA-LB) interactions and dispersion forces. The strength of these interactions is a key determinant in the dissolution of AEO–CO₂, while the structure of AEO facilitates its dissolution in CO₂. The number of CO₂ binding sites in AEO molecules increases with the free volume fraction and diffusion coefficient, allowing an optimal conformation with superior CO₂ affinity owing to greater contact with CO₂ molecules. Ethanol interacts with CO₂, thereby strengthening the LA-LB interactions and dispersion forces between AEO and CO₂ and thus significantly enhancing the solubility of AEO in CO₂.

Recommended Citation

N. Xu and Y. Wang and B. Bai and S. Cui and Z. Gao and Y. Zhang and D. Li and W. Shi and W. Ding and P. Ma, "Dissolution Mechanism of Nonionic Polyether Surfactants in Supercritical CO2," Energy and Fuels, vol. 39, no. 33, pp. 15601 - 15621, American Chemical Society, Aug 2025.

The definitive version is available at https://doi.org/10.1021/acs.energyfuels.5c02127

Department(s)

Geosciences and Geological and Petroleum Engineering

Second Department

Chemical and Biochemical Engineering

Comments

Key Technology Research and Development Program of Shandong Province, Grant 2022CXGC020303

International Standard Serial Number (ISSN)

1520-5029; 0887-0624

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2025 American Chemical Society, All rights reserved.

Publication Date

21 Aug 2025