AN AB INITIO MOLECULAR DYNAMICS STUDY ON THE SOLVATION OF FORMATE ION AND FORMIC ACID IN WATER

2012 ◽  
Vol 11 (05) ◽  
pp. 1019-1032 ◽  
Author(s):  
QIUBO CHEN ◽  
ZHIFENG LIU ◽  
CHEE HOW WONG

Formate ion and formic acid are linked in water by the equilibrium for the acidic dissociation of formic acid, which as the simplest carboxylic acid is an important model system. In this study, the microscopic details of the solvation around a formate ion and around a formic acid molecule in aqueous solution are explored by ab initio molecular dynamics simulations, at 300, 500, 700, and 900 K. The formate ion exerts a strong influence on the surrounding solvent molecules by hydrogen bonding, which restricts the access of other water molecules. With rising temperature, the hydrogen bonds are disrupted, and the space around formic acid becomes more accessible. Solvation of the formic acid is marked by its partial dissociation to produce a proton, and the hydrogen bond interaction around a formic acid is not as strong as that around a formate ion. The acidic dissociation becomes less favorable as temperature rises, which indicates a lesser catalytic role for the water molecules in the thermal dissociation of formic acid.

2018 ◽  
Vol 20 (36) ◽  
pp. 23717-23725 ◽  
Author(s):  
Vesa Hänninen ◽  
Garold Murdachaew ◽  
Gilbert M. Nathanson ◽  
R. Benny Gerber ◽  
Lauri Halonen

Ab initio molecular dynamics simulations of formic acid (FA) dimer colliding with liquid water at 300 K have been performed using density functional theory.


Crystals ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 73 ◽  
Author(s):  
Jinxiang Liu ◽  
Yujie Yan ◽  
Youguo Yan ◽  
Jun Zhang

Tetrahydrofuran (THF) is well known as a former and a promoter of clathrate hydrates, but the molecular mechanism for the formation of these compounds is not yet well understood. We performed ab initio calculations and ab initio molecular dynamics simulations to investigate the formation, structure, and stability of THF·(H2O)n=1–10 and its significance to the formation of the THF hydrate. Weak hydrogen bonds were found between THF and water molecules, and THF could promote water molecules from the planar pentagonal or hexagonal ring. As a promoter, THF could increase the binding ability of the CH4, CO2, or H2 molecule onto a water face, but could also enhance the adsorption of other THF molecules, causing an enrichment effect.


Author(s):  
Boris Merinov ◽  
Sergey Morozov

The proton transport mechanism in superprotonic phases of solid acids is a subject of experimental and theoretical studies for a number of years. Despite this, details of the mechanism still...


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