Molecular dynamics simulations of water-methanol mixtures

Pálinkás, G.; Hawlicka, Ewa; Heinzinger, K.

doi:10.1016/0301-0104(91)87055-z

Cited by 91 publications

(80 citation statements)

References 17 publications

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“…[18][19][20][21][22][23] Experimental studies, employing a wide range of experimental techniques, have thus far been inconclusive. [24][25][26] Neutron and X-ray diffraction studies of methanol-and ethanol-water mixtures have concluded that incomplete mixing alone can explain the negative excess entropy of mixing.…”

Section: -17mentioning

confidence: 99%

Communication: Hydrogen bonding interactions in water-alcohol mixtures from X-ray absorption spectroscopy

Lam

Smith

Saykally

2016

The Journal of Chemical Physics

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While methanol and ethanol are macroscopically miscible with water, their mixtures exhibit negative excess entropies of mixing. Despite considerable effort in both experiment and theory, there remains significant disagreement regarding the origin of this effect. Different models for the liquid mixture structure have been proposed to address this behavior, including the enhancement of the water hydrogen bonding network around the alcohol hydrophobic groups and microscopic immiscibility or clustering. We have investigated mixtures of methanol, ethanol, and isopropanol with water by liquid microjet X-ray absorption spectroscopy on the oxygen K-edge, an atomspecific probe providing details of both inter-and intra-molecular structure. The measured spectra evidence a significant enhancement of hydrogen bonding originating from the methanol and ethanol hydroxyl groups upon the addition of water. These additional hydrogen bonding interactions would strengthen the liquid-liquid interactions, resulting in additional ordering in the liquid structures and leading to a reduction in entropy and a negative enthalpy of mixing, consistent with existing thermodynamic data. In contrast, the spectra of the isopropanol-water mixtures exhibit an increase in the number of broken alcohol hydrogen bonds for mixtures containing up to 0.5 water mole fraction, an observation consistent with existing enthalpy of mixing data, suggesting that the measured negative excess entropy is a result of clustering or micro-immiscibility. Published by AIP Publishing. [http://dx

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Section: -17mentioning

confidence: 99%

Communication: Hydrogen bonding interactions in water-alcohol mixtures from X-ray absorption spectroscopy

Lam

Smith

Saykally

2016

The Journal of Chemical Physics

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“…Pure liquid methanol under various conditions [19][20][21][22][23][24][25][26][27][28][29][30][31], methanolic mixtures [32][33][34][35][36] as well as ionic solutions in methanol [37] and solutions of argon in methanol [38] have been studied earlier by MC and MD simulations. In most instances, the methanol The total potential is assumed to be the sum of these inter-and intramolecular terms.…”

Section: Experiments and Simulationsmentioning

confidence: 99%

“…De tails and the potential constants are given in [22]. We note that a slightly modified set of parameters for the Me-Me and O -M e interactions was introduced later [33]. These models have been used previously in many instances [22,23,[33][34][35].…”

Section: Experiments and Simulationsmentioning

confidence: 99%

“…We note that a slightly modified set of parameters for the Me-Me and O -M e interactions was introduced later [33]. These models have been used previously in many instances [22,23,[33][34][35]. The reorientational correlation functions and the corresponding correlation times presented here are obtained from NVE-MD simulations of 200 model molecules.…”

Section: Experiments and Simulationsmentioning

confidence: 99%

See 1 more Smart Citation

The Anisotropy of the Molecular Reorientational Motions in Liquid Methanol

Ludwig

Bopp

Zeidler

1995

Zeitschrift Für Naturforschung A

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Dedicated to Professor W . Müller-Warmuth on the occasion of his 65th birthday Nuclear magnetic resonance (NMR) relaxation time measurements on isotopically substituted samples yield a detailed understanding of the molecular reorientational dynamics in liquids. Reori entational correlation times obtained from such experiments are reported for two molecule-fixed vectors in pure liquid methanol. While the reorientational motions of single molecules are nearly isotropic at temperatures below 250 K, at 308 K the reorientational correlation time of the O-H vector becomes 2.3 times larger than that of the O-C vector. Molecular dynamics (MD) simulations give access to the complete correlation functions of the reorientational motions. Correlation times extracted from these functions fit well to the experiment in case of the O-C vector. At low temper atures, however, these times lie markedly above those obtained in the experiment for the O-H vector. Thus, the simulation yields reorientation times for the O-H vector that are, independent of the temperature, twice as large as those of the O-C vector.

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“…More recent theoretical calculations have indeed confirmed the greater stability of this isomer but obtained a relative stability that is less than 1 kcal/mol [13,14]. Although gas phase results are of interest in their own, it is also clear that the liquid situation may find a broader range of interest for alcohol-water mixtures [15,16,17,18]. Unfortunately, the results obtained for gas phase cannot be directly extrapolated to the liquid situation without a great risk.…”

Section: Introductionmentioning

confidence: 99%

Is There a Favorite Isomer for Hydrogen-Bonded Methanol in Water?

Fileti¹,

Coutinho²,

Canuto³

2004

Advances in Quantum Chemistry

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Sequential Monte Carlo/Quantum Mechanical calculations of the interaction energy of hydrogen-bonded methanol in liquid water gives the same result for methanol acting either as the proton donor or the proton acceptor. For the complex-optimized cases methanol acting as the proton acceptor, CH 3 HO· · ·H 2 O, is more stable than the proton donor, CH 3 OH· · ·OH 2 , by ∼ 0.5 kcal/mol. In the case of methanol in liquid water, at room temperature, statistically converged results, using counterpoise corrected MP2/aug-cc-pVDZ calculations, leads to the same binding energy in both cases.

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Molecular dynamics simulations of water-methanol mixtures

Cited by 91 publications

References 17 publications

Communication: Hydrogen bonding interactions in water-alcohol mixtures from X-ray absorption spectroscopy

Communication: Hydrogen bonding interactions in water-alcohol mixtures from X-ray absorption spectroscopy

The Anisotropy of the Molecular Reorientational Motions in Liquid Methanol

Is There a Favorite Isomer for Hydrogen-Bonded Methanol in Water?

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