Binary mixtures of supercritical carbon dioxide with methanol. A molecular dynamics simulation study

Molecular dynamics simulation of liquid methanol under the influence of an external electric field

“…Hydrogen bonds can usually be defined in computer simulation in two different ways, either on energetic or geometric criteria. We have used the following geometric definition of the hydrogen bond where two methanol molecules are taken to be hydrogen bonded if the oxygen-oxygen distance is less than 3.5Å, the hydrogen-oxygen distance is less than 2.45Å and the oxygen-oxygen-hydrogen angle θ is less than 30 • [26,27]. The quantities of interest are the percentages (f n ) of methanol molecules that engage in n hydrogen bonds (n) and the average number of hydrogen bonds per methanol molecule (n HB ).…”

Investigation of the local composition enhancement and related dynamics in supercritical CO2-cosolvent mixtures via computer simulation: The case of ethanol in CO2

“…Note that the experimental and theoretical studies concerning the properties of the alcohol-CO 2 sc mixed solvents and especially the existence of aggregates among the alcohol molecules in these sc mixtures are very limited. 25 According to previous molecular dynamics ͑MD͒ simulation studies of scCO 2 -MeOH mixtures performed by our group 25 ͑with mole fraction of MeOH Х 0.1͒ the MeOH molecules tend to form aggregates in the mixture by forming hydrogen bonds among them. This fact indicates that the local composition of MeOH around the MeOH ͑methanol͒ molecules is probably enhanced in the mixture.…”

“…26͑b͒ Furthermore, our previous studies have revealed that these aggregation effects among the MeOH influence strongly the single translational dynamics of the MeOH molecules, something which was in agreement with previous experimental nuclear magnetic resonance ͑NMR͒ studies. 27 Although a small number of experimental studies devoted to the properties of scCO 2 -MeOH mixtures at the composition range X MeOH Х 0.01-0.11 have been published up to now, [25][26][27][28][29][30][31][32][33][34][35] thorough investigations of the properties of scCO 2 -EtOH ͑ethanol͒ binary mixtures are scarce and most of them correspond mainly to dilute concentrations of ethanol. 30,[36][37][38][39][40][41] Therefore, the main objective of this study is to provide some information concerning the local intermolecular structure and related dynamics for the scCO 2 -EtOH binary mixtures at about 10% molar concentrations of ethanol and especially to seek for the existence of possible LCE effects around the ethanol cosolvent molecules.…”

“…In view of the great scientific and technological potentials of this mixed solvent, a deeper and quantitative understanding of the aforementioned effects becomes indispensable in order to elucidate fundamental aspects of this particularly interesting molecular system. This work is a part of our theoretical investigations on the properties of supercritical solvents 25,[42][43][44][45][46][47]55 and with this effort we would like to cover this gap by providing some quantitative information concerning these particular properties of this scCO 2 -cosolvent mixture.…”

Solvatochromism and Solvation Dynamics in CO2-Expanded Liquids

“…Molecular dynamics (MD) simulations in GXLs provide a means to answer this question and a number of GXL simulations have already been performed (5,(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21). In previous work (20), we reported experimentsimulation comparisons of absorption and emission shifts of two solutes in the set of C0 2 -expanded liquids presented in Figure 1.…”