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Title: Prediction of the free energy of dilute aqueous methane, ethane, and propane at temperatures from 600 to 1200 {degree}C and densities from 0 to 1 g cm{sup -3} using molecular dynamics simulations

Abstract

Molecular dynamics simulations of united atom Lennard-Jones model for methane, ethane, and propane in TIP3P water have been used to estimate the chemical potentials of aqueous methane, ethane, and propane from 600 to 1200 {degree}C and densities from 0 to 1 g cm{sup -3}. Estimates of the errors in the predictions due to the inadequacy of the models show that this method of prediction gives reasonable accuracy. The diameter ({sigma}) of the water-methane interaction is the most important parameter. The present predictions for methane are compared with a variety of other methods from the literature. An equation with seven adjustable parameters is presented which fits all of the simulation results as a function of temperature, density of water, and number of carbon atoms. This equation should allow reasonable extrapolations to predict the properties of butane, pentane, and hexane. An even simpler equation with only two adjustable parameters is able to fit all of the experimental data in this temperature and density region if the calculated solute-water second virial coefficient for this model is used. The fit is not quite as accurate as with the seven-parameter equation, but this equation should be useful for predictions of normal and branched hydrocarbons. 84more » refs., 6 figs., 5 tabs.« less

Authors:
;  [1]
  1. Univ. of Deleware, Newark, DE (United States)
Publication Date:
OSTI Identifier:
420869
DOE Contract Number:  
FG02-89ER14080
Resource Type:
Journal Article
Journal Name:
Journal of Physical Chemistry
Additional Journal Information:
Journal Volume: 100; Journal Issue: 40; Other Information: PBD: 3 Oct 1996
Country of Publication:
United States
Language:
English
Subject:
40 CHEMISTRY; 66 PHYSICS; 99 MATHEMATICS, COMPUTERS, INFORMATION SCIENCE, MANAGEMENT, LAW, MISCELLANEOUS; METHANE; LENNARD-JONES POTENTIAL; FREE ENERGY; PROPANE; MOLECULAR MODELS; AQUEOUS SOLUTIONS; TEMPERATURE RANGE; COMPUTERIZED SIMULATION; MATHEMATICAL MODELS; PHYSICAL CHEMISTRY; THEORETICAL DATA

Citation Formats

Lin, C L, and Wood, R H. Prediction of the free energy of dilute aqueous methane, ethane, and propane at temperatures from 600 to 1200 {degree}C and densities from 0 to 1 g cm{sup -3} using molecular dynamics simulations. United States: N. p., 1996. Web. doi:10.1021/jp961169v.
Lin, C L, & Wood, R H. Prediction of the free energy of dilute aqueous methane, ethane, and propane at temperatures from 600 to 1200 {degree}C and densities from 0 to 1 g cm{sup -3} using molecular dynamics simulations. United States. doi:10.1021/jp961169v.
Lin, C L, and Wood, R H. Thu . "Prediction of the free energy of dilute aqueous methane, ethane, and propane at temperatures from 600 to 1200 {degree}C and densities from 0 to 1 g cm{sup -3} using molecular dynamics simulations". United States. doi:10.1021/jp961169v.
@article{osti_420869,
title = {Prediction of the free energy of dilute aqueous methane, ethane, and propane at temperatures from 600 to 1200 {degree}C and densities from 0 to 1 g cm{sup -3} using molecular dynamics simulations},
author = {Lin, C L and Wood, R H},
abstractNote = {Molecular dynamics simulations of united atom Lennard-Jones model for methane, ethane, and propane in TIP3P water have been used to estimate the chemical potentials of aqueous methane, ethane, and propane from 600 to 1200 {degree}C and densities from 0 to 1 g cm{sup -3}. Estimates of the errors in the predictions due to the inadequacy of the models show that this method of prediction gives reasonable accuracy. The diameter ({sigma}) of the water-methane interaction is the most important parameter. The present predictions for methane are compared with a variety of other methods from the literature. An equation with seven adjustable parameters is presented which fits all of the simulation results as a function of temperature, density of water, and number of carbon atoms. This equation should allow reasonable extrapolations to predict the properties of butane, pentane, and hexane. An even simpler equation with only two adjustable parameters is able to fit all of the experimental data in this temperature and density region if the calculated solute-water second virial coefficient for this model is used. The fit is not quite as accurate as with the seven-parameter equation, but this equation should be useful for predictions of normal and branched hydrocarbons. 84 refs., 6 figs., 5 tabs.},
doi = {10.1021/jp961169v},
journal = {Journal of Physical Chemistry},
number = 40,
volume = 100,
place = {United States},
year = {1996},
month = {10}
}