van den Bruinhorst Adriaan, Corsini Chiara, Depraetère Guillaume, Cam Nithavong, Pádua Agílio, Costa Gomes Margarida
Ionic Liquids Group, Laboratoire de Chimie de l'École Normale Supérieure de Lyon, Centre Nationale de Recherche Scientifique, and Université de Lyon, 69364 Lyon, France.
Faraday Discuss. 2024 Oct 25;253(0):273-288. doi: 10.1039/d4fd00048j.
The large melting point depressions characterising deep eutectic solvents (DESs) are related to negative deviations from ideal mixing behaviour characterised by the excess Gibbs energy. Favourable excess Gibbs energies result from a balance between the excess entropy and enthalpy of mixing, which was experimentally determined for three choline chloride (ChCl) based mixtures using calorimetry. While the excess Gibbs energy of HO + ChCl is enthalpy dominated, those of ethylene glycol (EG) + ChCl and 1,3-propanediol + ChCl are entropy dominated. Molecular dynamics simulations using polarisable force-fields show intermolecular hydrogen bonds between DES constituents for HO + ChCl and EG + ChCl. Hence, inter-species hydrogen bonding does not guarantee enthalpy-dominated melting point depressions. We suggest future research to focus on tuning the entropy-enthalpy balance the chemical nature of the DES constituents.
表征深共熔溶剂（DESs）的大幅熔点降低与以过量吉布斯自由能为特征的理想混合行为的负偏差有关。有利的过量吉布斯自由能源于混合熵和混合焓之间的平衡，这是通过量热法对三种基于氯化胆碱（ChCl）的混合物进行实验测定的。虽然HO + ChCl的过量吉布斯自由能以焓为主导，但乙二醇（EG）+ ChCl和1,3 - 丙二醇 + ChCl的过量吉布斯自由能以熵为主导。使用可极化力场的分子动力学模拟显示了HO + ChCl和EG + ChCl的DES成分之间的分子间氢键。因此，种间氢键并不能保证焓主导的熔点降低。我们建议未来的研究集中于调整熵 - 焓平衡以及DES成分的化学性质。
