ABSTRACT

In this research, the equilibrium mole fraction solubility of 4-nitroaniline (4-NA) in some aqueous-ethanolic mixtures was determined at seven temperatures from (293.15 to 323.15) K. The respective apparent thermodynamic functions (Gibbs energy, enthalpy, and entropy) of the dissolution processes were computed using the van’t Hoff and Gibbs equations. The enthalpy-entropy relationship for 4-NA was non-linear in the plot of enthalpy vs. Gibbs energy of solution with negative slopes from neat water to the mixture w₁ = 0.10 and from w₁ = 0.20 to neat ethanol but positive slope from w₁ = 0.10 to w₁ = 0.20. Therefore, the driving mechanism for 4-NA transfer processes is the entropy in water-rich mixtures. Additionally, by means of the inverse Kirkwood-Buff integrals is observed that 4-NA is preferentially solvated by water molecules in water-rich mixtures but preferentially solvated by ethanol molecules in the mixtures of 0.23 ≤ x₁ ≤ 1.00.

摘要

在这项研究中，4-硝基苯胺 (4-NA) 在一些水-乙醇混合物中的平衡摩尔分数溶解度是在 (293.15 到 323.15) K 的七个温度下确定的。 各自的表观热力学函数（吉布斯能、焓和熵) 的溶解过程是使用 van't Hoff 和 Gibbs 方程计算的。4-NA 的焓-熵关系在焓与. 溶液的吉布斯能量从纯水到混合物w ₁  = 0.10 和从w ₁  = 0.20 到纯乙醇呈负斜率，但从w ₁  = 0.10 到w ₁呈正斜率 = 0.20。因此，4-NA 转移过程的驱动机制是富水混合物的熵。此外，通过逆柯克伍德-布夫积分，观察到 4-NA 在富水混合物中优先被水分子溶剂化，但在 0.23 ≤ x ₁  ≤ 1.00的混合物中优先被乙醇分子溶剂化 。