scholarly journals Density, Enthalpy of Vaporization and Local Structure of Neat N-Alkane Liquids

Liquids ◽  
2021 ◽  
Vol 1 (1) ◽  
pp. 47-59
Author(s):  
Gerrick E. Lindberg ◽  
Joseph L. Baker ◽  
Jennifer Hanley ◽  
William M. Grundy ◽  
Caitlin King
Keyword(s):  
Chemical Processes ◽  
Distribution Functions ◽  
Average Absolute Deviation ◽  
Average Deviation ◽  
Absolute Deviation ◽  
Amber Force Field ◽  
Local Structures ◽  
Ideal Solution Behavior ◽  
Experimental Values ◽  
Dynamics Simulations

The properties of alkanes are consequential for understanding many chemical processes in nature and industry. We use molecular dynamics simulations with the Amber force field GAFF2 to examine the structure of pure liquids at each respective normal boiling point, spanning the 15 n-alkanes from methane to pentadecane. The densities predicted from the simulations are found to agree well with reported experimental values, with an average deviation of 1.9%. The enthalpies of vaporization have an average absolute deviation from experiment of 10.4%. Radial distribution functions show that short alkanes have distinct local structures that are found to converge with each other with increasing chain length. This provides a unique perspective on trends in the n-alkane series and will be useful for interpreting similarities and differences in the n-alkane series as well as the breakdown of ideal solution behavior in mixtures of these molecules.

scholarly journals Molecular Dynamics Simulations of CO2Molecules in ZIF-11 Using Refined AMBER Force Field

2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
W. Wongsinlatam ◽  
T. Remsungnen
Keyword(s):  
Molecular Dynamics ◽  
Force Field ◽  
Molecular Dynamics Simulations ◽  
Distribution Functions ◽  
Binding Energies ◽  
Hydrogen Atoms ◽  
Amber Force Field ◽  
Bonding Parameters ◽  
Flexible Framework ◽  
Dynamics Simulations

Nonbonding parameters of AMBER force field have been refined based onab initiobinding energies of CO2–[C7H5N2]−complexes. The energy and geometry scaling factors are obtained to be 1.2 and 0.9 forεandσparameters, respectively. Molecular dynamics simulations of CO2molecules in rigid framework ZIF-11, have then been performed using original AMBER parameters (SIM I) and refined parameters (SIM II), respectively. The site-site radial distribution functions and the molecular distribution plots simulations indicate that all hydrogen atoms are favored binding site of CO2molecules. One slight but notable difference is that CO2molecules are mostly located around and closer to hydrogen atom of imidazolate ring in SIM II than those found in SIM I. The Zn-Zn and Zn-N RDFs in free flexible framework simulation (SIM III) show validity of adapting AMBER bonding parameters. Due to the limitations of computing resources and times in this study, the results of flexible framework simulation using refined nonbonding AMBER parameters (SIM IV) are not much different from those obtained in SIM II.

Article

1999 ◽  
Vol 77 (9) ◽  
pp. 1465-1470 ◽  
Author(s):  
Carmen E Hernández ◽  
Karina M De Fina ◽  
Lindsay E Roy ◽  
Tina L Sharp ◽  
William E Acree, Jr.
Keyword(s):  
Order Theory ◽  
Ideal Solution ◽  
Amino Ester ◽  
Average Absolute Deviation ◽  
Absolute Deviation ◽  
Solubility Predictions ◽  
Ideal Solution Behavior ◽  
Mobile Order Theory ◽  
Organic Nonelectrolyte ◽  
Mobile Order

Experimental solubilities are reported at 25.0°C for phenanthrene dissolved in 41 different organic nonelectrolyte solvents containing ether, carbonyl, hydroxy, chloro, amino, ester, methyl and tert-butyl functional groups. Results of these measurements are used to test the applications and limitations of expressions derived from Mobile Order theory. For the 31 solvents for which predictions could be made, computations show that Mobile Order theory does provide fairly reasonable estimates of the saturation mole fraction solubilities. Average absolute deviation between predicted and observed values is 41.3% (excluding acetonitrile). In comparison, the average absolute deviation is 1610% when ideal solution behavior is assumed. Also reported are experimental solubilities at 26°C for pyrene dissolved in 1-hexanol, 1-heptanol, ethylbenzene, aniline, and 2-butanone.Key words: phenanthrene solubilities, organic nonelectrolyte solvents, solubility predictions.

Study on structures and electronic properties of neutral and anionic TiSin(0,-1)(n = 1–8) clusters using G4 theory

2014 ◽  
Vol 13 (05) ◽  
pp. 1450038 ◽  
Author(s):  
Jun Lu ◽  
Jucai Yang ◽  
Zhifei Xing ◽  
Hongmei Ning
Keyword(s):  
Experimental Data ◽  
Ground State ◽  
Electronic Structures ◽  
Electron Affinities ◽  
Average Absolute Deviation ◽  
Absolute Deviation ◽  
Relative Stabilities ◽  
Dissociation Energies ◽  
Ground State Structures ◽  
Experimental Values

The geometries, electronic structures and energies of small TiSi n species (n = 1–8) and their anions were systematically investigated by G4 theory. The ground-state structures of these clusters are presented herein. For neutral TiSi n (n = 1–8), the spin multiplicities of the ground-state structures are singlet, with the exception of n = 2, which exists in a triplet state. For anionic TiSi n-, the spin multiplicities of the ground-state structures are doublet, with the exception of n = 2, which is quartet. The adiabatic electron affinities for TiSi n are estimated to be 1.31 eV ( TiSi ), 1.46 eV ( TiSi 2), 1.53 eV ( TiSi 3), 1.71 eV ( TiSi 4), 2.06 eV ( TiSi 5), 2.16 eV ( TiSi 6), 2.20 eV ( TiSi 7) and 2.39 eV ( TiSi 8). In comparison with the available experimental data, the calculated adiabatic electron affinities differ from experimental values by an average absolute deviation of only 0.03 eV. Additionally, the dissociation energies of Ti atoms from TiSi n, and Si atoms from TiSi n and Si n clusters are estimated to examine relative stabilities.

Solubility of trans-stilbene in organic nonelectrolyte solvents. Comparison of observed versus predicted values based upon mobile order theory

1997 ◽  
Vol 75 (3) ◽  
pp. 258-261 ◽  
Author(s):  
Kristin A. Fletcher ◽  
Mary E.R. McHale ◽  
Karen S. Coym ◽  
William E. Acree Jr.
Keyword(s):  
Order Theory ◽  
Average Absolute Deviation ◽  
Absolute Deviation ◽  
Solubility Predictions ◽  
Ideal Solution Behavior ◽  
Trans Stilbene ◽  
Mobile Order Theory ◽  
Organic Nonelectrolyte ◽  
Predicted Values ◽  
Mobile Order

Experimental solubilities are reported at 25.0 °C for trans-stilbene dissolved in 28 different organic nonelectrolyte solvents containing methyl, ether, hydroxy, and tert-butyl functional groups. Results of these measurements are used to test the applications and limitations of expressions derived from Mobile Order theory. For the 20 solvents for which predictions could be made, computations show that Mobile Order theory does provide fairly reasonable (although by no means perfect) estimates of the saturation mole fraction solubilities. Average absolute deviation between predicted and observed values is ca. 24%. In comparison, the average absolute deviation increases significantly to 935% when ideal solution behavior is assumed. KeyWords: trans-stilbene solubilities, organic nonelectrolyte solvents, solubility predictions.

Solubility of fluoranthene in organic nonelectrolyte solvents. Comparison of observed versus predicted values based upon Mobile Order theory

1998 ◽  
Vol 76 (9) ◽  
pp. 1312-1316 ◽  
Author(s):  
Carmen E Hernández ◽  
William E Acree, Jr.
Keyword(s):  
Order Theory ◽  
Ideal Solution ◽  
Average Absolute Deviation ◽  
Absolute Deviation ◽  
Solubility Predictions ◽  
Ideal Solution Behavior ◽  
Mobile Order Theory ◽  
Organic Nonelectrolyte ◽  
Predicted Values ◽  
Mobile Order

Experimental solubilities are reported at 25.0°C for fluoranthene dissolved in 36 different organic nonelectrolyte solvents containing ester, ether, hydroxy, chloro, methyl, and tert-butyl functional groups. Results of these measurements are used to test the applications and limitations of expressions derived from Mobile Order theory. For the 28 solvents for which predictions could be made, computations show that Mobile Order theory does provide fairly reasonable estimates of the saturation mole fraction solubilities. Average absolute deviation between predicted and observed values is 53%. In comparison, the average absolute deviation is 1574% when ideal solution behavior is assumed.Key words: fluoranthene solubilities, organic nonelectrolyte solvents, solubility predictions.

Solubility of hexachlorobenzene in organic nonelectrolyte solvents. Comparison of observed vs. predicted values based upon Mobile Order model

2000 ◽  
Vol 78 (4) ◽  
pp. 459-463
Author(s):  
Karina M De Fina ◽  
Tiffany T Van ◽  
William E Acree, Jr.
Keyword(s):  
Functional Groups ◽  
Ideal Solution ◽  
Average Absolute Deviation ◽  
Order Model ◽  
Absolute Deviation ◽  
Solubility Predictions ◽  
Ideal Solution Behavior ◽  
Organic Nonelectrolyte ◽  
Predicted Values ◽  
Mobile Order

Experimental solubilities are reported at 25.0°C for hexachlorobenzene dissolved in 42 different organic nonelectrolyte solvents containing ether-, chloro-, hydroxy-, ester, methyl-, and tert-butyl-functional groups. Results of these measurements are used to test the applications and limitations of expressions derived from Mobile Order model. For the 33 solvents for which predictions could be made computations show that Mobile Order model does provide fairly reasonable estimates of the saturation mole fraction solubilities. Average absolute deviation between predicted and observed values is 210%. In comparison, the average absolute deviation is 2 060% when ideal solution behavior is assumed.Key words: hexachlorobenzene solubilities, organic nonelectrolyte solvents, solubility predictions.

Solubility of diphenyl sulfone in organic nonelectrolyte solvents. Comparison of observed vs. predicted values based upon Mobile Order theory

2000 ◽  
Vol 78 (4) ◽  
pp. 449-453 ◽  
Author(s):  
Karina M De Fina ◽  
Tiffany T Van ◽  
Kristin A Fletcher ◽  
William E Acree, Jr.
Keyword(s):  
Order Theory ◽  
Average Absolute Deviation ◽  
Absolute Deviation ◽  
Diphenyl Sulfone ◽  
Solubility Predictions ◽  
Ideal Solution Behavior ◽  
Mobile Order Theory ◽  
Organic Nonelectrolyte ◽  
Predicted Values ◽  
Mobile Order

Experimental solubilities are reported at 25.0°C for diphenyl sulfone dissolved in 25 different organic nonelectrolyte solvents containing ether-, chloro-, hydroxy-, ester, methyl-, and tert-butyl-functional groups. Results of these measurements, combined with previously reported diphenyl sulfone solubilities taken from the chemical literature, are used to test the applications and limitations of expressions derived from Mobile Order theory. For the 34 solvents for which predictions could be made, computations show that mobile order theory does provide fairly reasonable estimates of the saturation mole fraction solubilities. Average absolute deviation between predicted and observed values is 49.3%. In comparison, the average absolute deviation is 5 500% when ideal solution behavior is assumed.Key words: diphenyl sulfone solubilities, organic nonelectrolyte solvents, solubility predictions.

Solubility of acenaphthene in organic nonelectrolyte solvents. Comparison of observed versus predicted values based upon Mobile Order theory

1999 ◽  
Vol 77 (9) ◽  
pp. 1537-1541 ◽  
Author(s):  
Karina M De Fina ◽  
Tina L Sharp ◽  
William E Acree, Jr.
Keyword(s):  
Order Theory ◽  
Ideal Solution ◽  
Average Absolute Deviation ◽  
Absolute Deviation ◽  
Solubility Predictions ◽  
Ideal Solution Behavior ◽  
Mobile Order Theory ◽  
Organic Nonelectrolyte ◽  
Predicted Values ◽  
Mobile Order

Experimental solubilities are reported at 25.0°C for acenaphthene dissolved in 36 different organic nonelectrolyte solvents containing ether-, carbonyl-, hydroxy-, ester, methyl-, and tert-butyl functional groups. Results of these measurements are used to test the applications and limitations of expressions derived from Mobile Order theory. For the 29 solvents for which predictions could be made computations show that Mobile Order theory does provide fairly reasonable estimates of the saturation mole fraction solubilities. Average absolute deviation between predicted and observed values is 37.8%. In comparison, the average absolute deviation is 1080% when ideal solution behavior is assumed.Key words: acenaphthene solubilities, organic nonelectrolyte solvents, solubility predictions.

A Model for Extending the Heptanes plus Fraction for Trinidad Gas Condensates

2014 ◽  
Author(s):  
R.. Mayrhoo ◽  
R.. Hosein
Keyword(s):  
Experimental Data ◽  
Equation Of State ◽  
Compositional Data ◽  
Distribution Functions ◽  
Gas Condensate ◽  
Accurate Description ◽  
Average Absolute Deviation ◽  
Absolute Deviation ◽  
Mole Percent ◽  
Gas Condensates

Abstract An accurate description of pseudo-component compositions is required for Equation of State predictions for gas condensate systems. Very often these extended experimental data are unavailable and must be generated using mathematical models, of which the exponential and the three-parameter gamma distribution functions are the two most widely used. The development of these two techniques was based on the assumption of a continuous molar relationship for pseudo-components. However, experimental compositional data for gas condensate systems show discontinuities in this relationship at SCN8 and SCN13. The above models when applied to extend the C7+ fraction for Trinidad gas condensates, under predict the SCN8 mole percent and over predict the SCN12 mole percent due to the aforementioned discontinuities. The Average Absolute Deviation between the predicted and experimental SCN8 and SCN12 data were both greater than 25 percent. The two coefficient method described by Ahmed et al., when applied to extend the C7+ fraction, reduced the discontinuity at SCN8 to less than 12 percent. However the SCN12 group still had a deviation greater than 18 percent. These results show that existing models were not designed to take care of these discontinuities and should be used with caution when extending experimental data beyond SCN7. The Model described in this study resolves these discontinuities in the molar relationships at both SCN8 and SCN12 with an Average Absolute Deviation between the predicted and experimental compositions of less than 10 percent. This model can quite easily be included in Equation of State packages for a more accurate description of compositions for Trinidad gas condensates for performing compositional simulation studies. A partial analysis beyond the C7+ fraction is not required with this new model.

scholarly journals Unveiling Carbon Dioxide and Ethanol Diffusion in Carbonated Water-Ethanol Mixtures by Molecular Dynamics Simulations

Molecules ◽  
2021 ◽  
Vol 26 (6) ◽  
pp. 1711
Author(s):  
Mohamed Ahmed Khaireh ◽  
Marie Angot ◽  
Clara Cilindre ◽  
Gérard Liger-Belair ◽  
David A. Bonhommeau
Keyword(s):  
Carbon Dioxide ◽  
Molecular Dynamics ◽  
Diffusion Coefficients ◽  
Hydrodynamic Radius ◽  
Md Simulations ◽  
Molecular Models ◽  
Experimental Values ◽  
Carbon Dioxide Co2 ◽  
Dynamics Simulations ◽  
Apparent Disagreement

The diffusion of carbon dioxide (CO2) and ethanol (EtOH) is a fundamental transport process behind the formation and growth of CO2 bubbles in sparkling beverages and the release of organoleptic compounds at the liquid free surface. In the present study, CO2 and EtOH diffusion coefficients are computed from molecular dynamics (MD) simulations and compared with experimental values derived from the Stokes-Einstein (SE) relation on the basis of viscometry experiments and hydrodynamic radii deduced from former nuclear magnetic resonance (NMR) measurements. These diffusion coefficients steadily increase with temperature and decrease as the concentration of ethanol rises. The agreement between theory and experiment is suitable for CO2. Theoretical EtOH diffusion coefficients tend to overestimate slightly experimental values, although the agreement can be improved by changing the hydrodynamic radius used to evaluate experimental diffusion coefficients. This apparent disagreement should not rely on limitations of the MD simulations nor on the approximations made to evaluate theoretical diffusion coefficients. Improvement of the molecular models, as well as additional NMR measurements on sparkling beverages at several temperatures and ethanol concentrations, would help solve this issue.

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