从明尼苏达州溶解数据库中预测溶解自由能量,使用基于PC-SAFT状态方程的经典密度函数理论
Benjamin Bursik1, Johannes Eller1, Joachim Gross1
1Institute of Thermodynamics and Thermal Process Engineering, University of Stuttgart, Stuttgart 70569, Germany.
The journal of physical chemistry. B
|April 5, 2024
概括
本研究评估了密度函数理论 (DFT),使用PC-SAFT状态方程来预测碳化合物溶剂中的溶解自由能量. PC-SAFT DFT方法为计算这些能量提供了一种计算效率高和预测方法.
科学领域:
- 物理化学 物理化学
- 计算化学计算化学
- 热力学是一种热力学.
背景情况:
- 准确预测溶解自由能量对于理解化学过程至关重要.
- 经典密度函数理论 (DFT) 和扰乱链统计关联流体理论 (PC-SAFT) 是物理化学中确立的方法.
- 现有的现象学模型往往缺乏准确性或是计算上昂贵.
研究的目的:
- 批判性地评估PC-SAFT DFT在预测碳化合物溶剂中小分子的溶解自由能量方面的能力.
- 将PC-SAFT DFT的准确性与实验数据和其他理论模型进行比较.
- 为了确定PC-SAFT DFT方法中的错误来源和局限性.
主要方法:
- 使用密度函数理论 (DFT) 与扰乱链统计关联流体理论 (PC-SAFT) 状态方程相结合.
- 将预测的溶解自由能量与明尼苏达州溶解数据库中的实验数据进行比较.
- 使用统计方法分析准确性,计算各种碳化合物溶剂类别的平均绝对误差 (MAE).
主要成果:
- 在PC-SAFT DFT中,N-溶剂的平均绝对误差 (MAE) 为3.7kJmol-1和周期性碳化合物溶剂的4.2kJmol-1.
- 确定了关键的错误来源,包括忽略了库伦比相互作用,溶解物莱纳德-斯参数和洛伦茨-伯塞洛特结合规则.
- 与标准现象学模型和显式分子模拟相比,证明了更高的准确性和计算效率.
结论:
- PC-SAFT DFT提供了一种具有预测性和计算效率的方法,用于计算非极地和弱极地系统中的溶解自由能量.
- 仅使用PC-SAFT状态方程,并使用可用的溶液参数,也可以准确预测溶解自由能量 (MAE < 2.51 kJ mol-1).
- DFT方法是通用的,适用于任何可用分子力场表示的溶液,而不需要特定的PC-SAFT溶液参数.
更多相关视频
10:52Multiscale Sampling of a Heterogeneous Water/Metal Catalyst Interface using Density Functional Theory and Force-Field Molecular Dynamics
Published on: April 12, 2019
12.8K
06:37Analyzing Melts and Fluids from Ab Initio Molecular Dynamics Simulations with the UMD Package
Published on: September 17, 2021
4.5K
相关概念视频
02:05Entropy and Solvation
7.1K
The process of surrounding a solute with solvent is called solvation. It involves evenly distributing the solute within the solvent. The rule of thumb for determining a solvent for a given compound is that like dissolves like. A good solvent has molecular characteristics similar to those of the compound to be dissolved. For example, polar solutions dissolve polar solutes, and apolar solvents dissolve apolar solutes. A polar solvent is a solvent that has a high dielectric constant (ϵ...
7.1K
02:21Chemical and Solubility Equilibria
4.1K
The free energy change associated with dissolving a solute in a liter of solvent is called the free energy of a solution, ΔGsolution. The overall ΔGsolution is expressed as the balance of ΔGinteraction against the always-favorable free-energy of mixing, ΔGmixing. Solution formation is favorable if ΔGsolution is less than zero, whereas it is unfavorable if ΔGsolution is greater than zero. In short, for a solution to form and complete dissolution to take place,...
4.1K
02:12Solvating Effects
7.5K
An understanding of the solvating effect helps rationalize the relation between solvation and acidity of the compound. In addition, this also explains the relative stability of conjugate bases for compounds with different pKa values. This lesson details, in-depth, the principle of solvating effects. The strength of an acid and the stability of its corresponding conjugate base are determined using pKa values. This observed relationship is a consequence of solvation, which is the interaction...
7.5K
02:49Calculating Standard Free Energy Changes
21.2K
The free energy change for a reaction that occurs under the standard conditions of 1 bar pressure and at 298 K is called the standard free energy change. Since free energy is a state function, its value depends only on the conditions of the initial and final states of the system. A convenient and common approach to the calculation of free energy changes for physical and chemical reactions is by use of widely available compilations of standard state thermodynamic data. One method involves the...
21.2K
03:12Freezing Point Depression and Boiling Point Elevation
34.7K
Boiling Point Elevation
The boiling point of a liquid is the temperature at which its vapor pressure is equal to ambient atmospheric pressure. Since the vapor pressure of a solution is lowered due to the presence of nonvolatile solutes, it stands to reason that the solution’s boiling point will subsequently be increased. Vapor pressure increases with temperature, and so a solution will require a higher temperature than will pure solvent to achieve any given vapor pressure, including one...
The boiling point of a liquid is the temperature at which its vapor pressure is equal to ambient atmospheric pressure. Since the vapor pressure of a solution is lowered due to the presence of nonvolatile solutes, it stands to reason that the solution’s boiling point will subsequently be increased. Vapor pressure increases with temperature, and so a solution will require a higher temperature than will pure solvent to achieve any given vapor pressure, including one...
34.7K
03:08Electrolytes: van't Hoff Factor
33.1K
Colligative Properties of Electrolytes
The colligative properties of a solution depend only on the number, not on the identity, of solute species dissolved. The concentration terms in the equations for various colligative properties (freezing point depression, boiling point elevation, osmotic pressure) pertain to all solute species present in the solution. Nonelectrolytes dissolve physically without dissociation or any other accompanying process. Each molecule that dissolves yields one...
The colligative properties of a solution depend only on the number, not on the identity, of solute species dissolved. The concentration terms in the equations for various colligative properties (freezing point depression, boiling point elevation, osmotic pressure) pertain to all solute species present in the solution. Nonelectrolytes dissolve physically without dissociation or any other accompanying process. Each molecule that dissolves yields one...
33.1K