Miscibility and diffusivity of water in organic acids: Molecular dynamics simulations

Molecular dynamics simulations were performed to study both the structural and dynamic properties of n-alkyl carboxylic acid/water/n-alkyl carboxylic acid system with different alkyl chain length, such as acetic (CH3COOH) (A/W/A system), butyric (CH3(CH2)(2)COOH) (B/W/B system) and hexanoic (CH3(CH2)(4)COOH) (H/W/H system) acids. The mass density profiles along the interface normal to the organic acid/water system, the difference in the local structure of H2O molecules in bulk and in the vicinity of interface for A/W/A, B/W/B and H/W/H systems, as well as the diffusion behavior of water molecules at the interface with abovementioned organic acids, in the wide range of the temperature changes, have been investigated. Because of the central importance of water to the biology and pharmacology a number of new calculated regimes of miscibility and diffusivity of water molecules in carboxylic acids help us to better analyze such organic systems. (C) 2019 Elsevier B.V. All rights reserved.