Effect of the solvent quadrupolarizability on the strength of the hydrogen bond: Theory vs data for the Gibbs energy and enthalpy of homo- and heteroassociation between carboxylic acids and water
Effect of the solvent quadrupolarizability on the strength of the hydrogen bond: Theory vs data for the Gibbs energy and enthalpy of homo- and heteroassociation between carboxylic acids and water
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DOI：
10.1063/5.0137052
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发表时间：
2023-06-07
影响因子：
4.4
通讯作者：
Slavchov, Radomir I.
中科院分区：
文献类型：
--
作者：
Farren, Lana J.;Sharifi, Najib;Slavchov, Radomir I.
已经开发了溶剂对非极性液体中极性物质二聚热力学参数影响的空腔模型，并与实验数据进行了比较。已经收集了硬脂酸在环己烷和甲苯中的本体溶液数据，以根据二聚体自解离常数 K-d 来量化酸的自缔合程度。收集了成分和与温度相关的实验数据，以确定 K-d、解离焓和与温度相关的红外摩尔吸收系数。硬脂酸与非水溶剂中存在的少量水的相互作用也可以用异解离（或脱水）常数 K-h 来解决和量化。还考虑了乙酸的现有数据。该模型将 K-d 和 K-h 连接到气相缔合平衡。研究表明，溶质偶极-溶剂四极相互作用对四极液体（例如甲苯、苯和 CS2）中的 K-d 有重大影响。这项工作为这些添加剂从非水溶剂到固体表面的吸附研究提供了重要的背景，并与商业流体相关，例如油基腐蚀抑制剂和摩擦改进剂。此外，所提出的溶剂对 K-d 影响的理论是将计算化学中的标准隐式溶剂模型（例如可极化连续介质模型）推广到具有显着四极强度的介质的第一步。预计这对于溶解在与碳捕获和储存相关的二氧化碳中的极性物种尤其重要，而目前尚不存在适当的模型。
A cavity model of the effect of a solvent on thermodynamic parameters of dimerization of polar species in non-polar liquids has been developed and compared to experimental data. Bulk solution data have been collected for stearic acid in cyclohexane and in toluene to quantify the extent of self-association of the acid in terms of the dimer self-dissociation constant, K-d. Composition and temperature-dependent experimental data have been collected to determine K-d, the enthalpy of dissociation, and temperature-dependent infrared molar absorption coefficients. The interaction of stearic acid with small amounts of water present in non-aqueous solvents is also addressed and quantified with a hetero-dissociation (or dehydration) constant, K-h. Existing data for acetic acid are also considered. The model connects K-d and K-h to the vapor-phase association equilibria. Solute dipole-solvent quadrupole interactions are shown to have a major effect on K-d in quadrupolar liquids, such as toluene, benzene, and CS2. This work provides important background as a prelude to adsorption studies of these additives from non-aqueous solvents to solid surfaces with relevance to commercial fluids, such as oil-based corrosion inhibitors and friction modifiers. Moreover, the presented theory of the solvent effect on K-d is a first step to generalization of standard implicit solvent models in computational chemistry (such as the polarizable continuum model) to media of significant quadrupolar strength. This is expected to be particularly important for polar species dissolved in CO2 relevant for carbon capture and storage where appropriate models do not currently exist.