Molecular Insights of Refrigerants (R-32, R-125, R-134a) In Amino acid based Ionic Liquids

IF 2.9 4区化学 Q4 BIOCHEMISTRY & MOLECULAR BIOLOGY

Journal of Molecular Modeling Pub Date : 2026-10-13 DOI:10.1007/s00894-026-06999-8

Brundha Devi A, Sweta Jha, Praveenkumar Sappidi

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引用次数: 0

Abstract

Context

The separation of refrigerant mixtures is an important challenge in the development of sustainable cooling technologies, and ionic liquids (ILs) have emerged as promising alternative absorbents because of their tunable physicochemical properties. In this work, molecular-level interactions between three hydrofluorocarbon refrigerants (R-32, R-125, and R-134a) and amino acid (AA)–based ILs were investigated to understand their separation behavior. The ILs consisted of tetrabutylphosphonium ([TBP]) as the common cation paired with leucine ([LEU]) and isoleucine ([ILE]) anions. Structural, dynamic, and thermodynamic analyses revealed distinct differences in the behavior of the refrigerants within the IL environment. Among the three refrigerants, R-32 exhibited self-diffusivity approximately one order of magnitude higher than that of R-125 and R-134a in both ILs, indicating greater molecular mobility. RDF and interaction analyses showed that the [TBP] cation forms stronger intermolecular interactions with the refrigerants than the amino acid anions. Free-energy calculations further demonstrated that R-134a exhibits approximately 75% more favorable (i.e., more negative) solvation free energy than R-32 in [TBP][ILE], suggesting a stronger affinity for this IL. These findings provide molecular-level insights into refrigerant-IL interactions and support the rational selection of amino acid–based ILs for efficient refrigerant separation.

Methods

MD simulations were performed to investigate the structural organization, diffusion behavior, and thermodynamic properties of refrigerants in amino acid–based ILs. Systems containing R-32, R-125, and R-134a dissolved in [TBP][LEU] and [TBP][ILE] were simulated under equilibrium conditions. Structural properties were characterized using RDF and coordination analyses, while molecular mobility was evaluated using MSD and self-diffusion coefficient calculations. Thermodynamic behavior was examined by calculating the solvation free energy of the refrigerants in each IL. All MD simulations and trajectory analyses were carried out using the force field and simulation software described in the manuscript.

Graphical abstract

查看原文本刊更多论文

氨基酸基离子液体中制冷剂（R-32, R-125, R-134a）的分子特性。

背景：制冷剂混合物的分离是可持续冷却技术发展中的一个重要挑战，离子液体（ILs）由于其可调节的物理化学性质而成为有前途的替代吸收剂。在这项工作中，研究了三种氢氟碳制冷剂（R-32， R-125和R-134a）与氨基酸（AA）基il之间的分子水平相互作用，以了解它们的分离行为。四丁基膦（[TBP]）作为公共阳离子与亮氨酸（[LEU]）和异亮氨酸（[ILE]）阴离子配对。结构、动态和热力学分析揭示了在IL环境中制冷剂行为的明显差异。在这三种制冷剂中，R-32的自扩散率比R-125和R-134a高约一个数量级，表明分子迁移率更高。RDF和相互作用分析表明，与氨基酸阴离子相比，[TBP]阳离子与制冷剂形成更强的分子间相互作用。自由能计算进一步表明，在[TBP][ILE]中，R-134a比R-32表现出约75%的有利（即更负的）溶剂化自由能，这表明R-134a对这种IL具有更强的亲和力。这些发现为制冷剂-IL相互作用提供了分子水平的见解，并支持基于氨基酸的IL的合理选择，以实现有效的制冷剂分离。方法：采用分子动力学模拟方法研究氨基酸基液体中制冷剂的结构组织、扩散行为和热力学性质。在平衡条件下模拟了溶解在[TBP][LEU]和[TBP][ILE]中含有R-32、R-125和R-134a的体系。利用RDF和配位分析表征了结构性质，利用MSD和自扩散系数计算评价了分子迁移率。通过计算每个IL中制冷剂的溶剂化自由能来检查热力学行为。所有的MD模拟和轨迹分析都是使用手稿中描述的力场和模拟软件进行的。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Journal of Molecular Modeling 化学-化学综合

CiteScore

3.50

自引率

4.50%

发文量

362

审稿时长

2.9 months

期刊介绍： The Journal of Molecular Modeling focuses on "hardcore" modeling, publishing high-quality research and reports. Founded in 1995 as a purely electronic journal, it has adapted its format to include a full-color print edition, and adjusted its aims and scope fit the fast-changing field of molecular modeling, with a particular focus on three-dimensional modeling. Today, the journal covers all aspects of molecular modeling including life science modeling; materials modeling; new methods; and computational chemistry. Topics include computer-aided molecular design; rational drug design, de novo ligand design, receptor modeling and docking; cheminformatics, data analysis, visualization and mining; computational medicinal chemistry; homology modeling; simulation of peptides, DNA and other biopolymers; quantitative structure-activity relationships (QSAR) and ADME-modeling; modeling of biological reaction mechanisms; and combined experimental and computational studies in which calculations play a major role.