Molecular Dynamics Investigation of the Effects of Concentration on Hydrogen Bonding in Aqueous Solutions of Methanol, Ethylene Glycol and Glycerol

Abstract

Hydrogen bonding interaction between alcohols and water molecules is an important characteristic in the aqueous solutions of alcohols. In this paper, a series of molecular dynamics simulations have been performed to investigate the aqueous solutions of low molecular weight alcohols (methanol, ethylene glycol and glycerol) at the concentrations covering a broad range from 1 to 90 mol %. The work focuses on studying the effect of the alcohols molecules on the hydrogen bonding of water molecules in binary mixtures. By analyzing the hydrogen bonding ability of the hydroxyl (-OH) groups for the three alcohols, it is found that the hydroxyl group of methanol prefers to form more hydrogen bonds than that of ethylene glycol and glycerol due to the intra-and intermolecular effects. It is also shown that concentration has significant effect on the ability of alcohol molecule to hydrogen bond water molecules. Understanding the hydrogen bonding characteristics of the aqueous solutions is helpful to reveal the cryoprotective mechanisms of methanol, ethylene glycol and glycerol in aqueous solutions.

Effect of hydrogen bonding on self-diffusion in methanol/water liquid mixtures: A molecular dynamics simulation study

“…The empty H-bonding sites are mainly occupied by methanol molecules in the form of W-M H-bonds. Thus the number of W-M H-bonds increases with the concentrationincreases, which has been reported in Ref[1]. That is to say, the increasing concentration of methanol leads to simple H-bonding transfer from water-water complex to methanol-water complex[22].…”

“…The hydroxyl group of each methanol molecule can simultaneously act as H-bond donor and acceptor, and the methyl group has a negative effect on the formation of H-bonds [5]. The structure arrangement of the methanol/water mixtures has close correlation with the local hydration structure and dynamics of the amphiphilic solutes in the polar solvent [1,6].…”

“…In aqueous solutions, amphiphiles exhibit attractive and powerful ability of organizing the local structure where the amphiphilic molecules tend to be pushed together by the low affinity of water to the hydrophobic groups, and hydrogen bond (H-bond) to the surrounding water molecules by hydrophilic groups [1]. The H-bonds between amphiphilic molecules and water is a substitution of the H-bonds between water molecules, resulting in the rearrangement of the local hydrogen bonding (H-bonding) structure.…”

Low-Density Water Structure Observed in a Nanosegregated Cryoprotectant Solution at Low Temperatures from 285 to 238 K

“…Although there have been a large number of computational studies on glycerol and glycerol–water mixtures, including refs and − , experimental studies yielding information on liquid structure are more limited. ,, In the past 4 years, we have completed experimental structural studies of pure glycerol and glycerol–water mixtures at 298 K using a combination of neutron diffraction and computational modeling. − Our studies have shown that, at intermediate concentrations ( x g = 0.25–0.50), the mixture segregates on the nanometer length scale to form water-rich and glycerol-rich clusters. , This nanosegregation results in regions that exist as hydrogen-bonded clusters that differ in size across the concentration range. In the concentrated glycerol region ( x g = 0.80), a large glycerol cluster exists that spans the full size of the system.…”

Glucose Glycation of α-Lactalbumin and β-Lactoglobulin in Glycerol Solutions

“…On one hand, the decrease of water content in the solutions greatly contributed to the decrease of water activity. On the other hand, a glycerol molecule processes three hydroxyls with variable ability to form hydrogen bonds with water molecules, and the lifetime of hydrogen bonds between glycerol and water is longer than those among water molecules themselves, according to molecular dynamics. , The information mentioned above might also contribute to the reduction of fugacity of water, leading to the decrease of water activity. With such a decrease of water content, the unfavorable effect of water on glycation was released.…”