Work

Quantifying the Molecular Structural Effects on the Reaction Kinetics and Equilibrium Between Organic Amines and CO2: Insights from Theoretical Calculations

Year: 2025

Type: article

Abstract: Understanding how molecular structure governs the reactivity of organic amines with CO2 is essential for the rational design of next-generation carbon-capture solvents. In this work, three representative series of amines, including linear aliphatic, cyclic aliphatic, and aromatic, were systematically conducted with substituents at different positions, and their reaction rate constants and equilibrium constants with CO2 were calculated using transition state theory. A suite of electronic-structure and steric descriptors, including ALIE, Hirshfeld charge, Fukui functions, and ESP-derived parameters, was developed to quantify structure–reactivity relationships. Linear aliphatic amines were found to be most sensitive to steric hindrance, while cyclic and aromatic amines were predominantly governed by inductive and conjugation effects. Key descriptors such as N_ALIE and q(N) showed strong correlations with both kinetic and thermodynamic parameters, enabling quantitative interpretation of substituent effects. Notably, a positive linear correlation between ln(k) and ln(K) was observed across all amine classes, revealing an intrinsic coupling between reaction rate and equilibrium. These findings deepen the mechanistic understanding of CO2–amine chemistry and provide a theoretical foundation for the targeted design and optimization of high-performance CO2-capture solvents.

Source: Separations

DOI: 10.3390/separations13010016

Authors: Yupeng Cui, Qiyue Zhao, Yousheng Zhou, Chuanlei Liu, Hui Sun

Institutions: East China University of Science and Technology, Xinjiang University

Language: English

Topic: Carbon Dioxide Capture Technologies

Subfield: Mechanical Engineering

Field: Engineering

Domain: Physical Sciences

SDG: Climate action

Open Access status: gold

Estimated APC paid: $3,137