A combined group contribution and molecular geometry approach for predicting melting points of aliphatic compounds

Luwei Zhao, Samuel H Yalkowsky

Research output: Contribution to journalArticle

55 Citations (Scopus)

Abstract

A combined approach that utilizes both group contribution and simple molecular geometric parameters is employed to predict normal melting points for a variety of aliphatic compounds. The melting points are estimated from the ratio of the enthalpy and the entropy of melting. The former is calculated from the sum of enthalpic group contributions and correction factors, whereas the latter is calculated using a modification of Walden's rule. Approximately 1040 melting point data were compiled and analyzed by multiple regression. The root-mean-square error of the estimation is 34.4 K. This is relatively low given the complexity of melting and the diversity of the database used. A comparison of the proposed method with the method of Joback and Reid8 was performed on 50 aliphatic compounds that were not used in the training set. The average absolute error for this method is approximately 20%, whereas that for the Joback and Reid data is 34%. The higher prediction accuracy of the proposed method suggests that the melting point prediction can better be approached by using both group contribution (enthalpic) and simple molecular geometric parameters (entropic).

Original languageEnglish (US)
Pages (from-to)3581-3584
Number of pages4
JournalIndustrial and Engineering Chemistry Research
Volume38
Issue number9
StatePublished - 1999

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Melting point
melting
geometry
Geometry
Melting
Mean square error
Enthalpy
Entropy
prediction
enthalpy
multiple regression
entropy
aliphatic compound
method
parameter

ASJC Scopus subject areas

  • Chemical Engineering (miscellaneous)
  • Environmental Science(all)
  • Polymers and Plastics

Cite this

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title = "A combined group contribution and molecular geometry approach for predicting melting points of aliphatic compounds",
abstract = "A combined approach that utilizes both group contribution and simple molecular geometric parameters is employed to predict normal melting points for a variety of aliphatic compounds. The melting points are estimated from the ratio of the enthalpy and the entropy of melting. The former is calculated from the sum of enthalpic group contributions and correction factors, whereas the latter is calculated using a modification of Walden's rule. Approximately 1040 melting point data were compiled and analyzed by multiple regression. The root-mean-square error of the estimation is 34.4 K. This is relatively low given the complexity of melting and the diversity of the database used. A comparison of the proposed method with the method of Joback and Reid8 was performed on 50 aliphatic compounds that were not used in the training set. The average absolute error for this method is approximately 20{\%}, whereas that for the Joback and Reid data is 34{\%}. The higher prediction accuracy of the proposed method suggests that the melting point prediction can better be approached by using both group contribution (enthalpic) and simple molecular geometric parameters (entropic).",
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AU - Zhao, Luwei

AU - Yalkowsky, Samuel H

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N2 - A combined approach that utilizes both group contribution and simple molecular geometric parameters is employed to predict normal melting points for a variety of aliphatic compounds. The melting points are estimated from the ratio of the enthalpy and the entropy of melting. The former is calculated from the sum of enthalpic group contributions and correction factors, whereas the latter is calculated using a modification of Walden's rule. Approximately 1040 melting point data were compiled and analyzed by multiple regression. The root-mean-square error of the estimation is 34.4 K. This is relatively low given the complexity of melting and the diversity of the database used. A comparison of the proposed method with the method of Joback and Reid8 was performed on 50 aliphatic compounds that were not used in the training set. The average absolute error for this method is approximately 20%, whereas that for the Joback and Reid data is 34%. The higher prediction accuracy of the proposed method suggests that the melting point prediction can better be approached by using both group contribution (enthalpic) and simple molecular geometric parameters (entropic).

AB - A combined approach that utilizes both group contribution and simple molecular geometric parameters is employed to predict normal melting points for a variety of aliphatic compounds. The melting points are estimated from the ratio of the enthalpy and the entropy of melting. The former is calculated from the sum of enthalpic group contributions and correction factors, whereas the latter is calculated using a modification of Walden's rule. Approximately 1040 melting point data were compiled and analyzed by multiple regression. The root-mean-square error of the estimation is 34.4 K. This is relatively low given the complexity of melting and the diversity of the database used. A comparison of the proposed method with the method of Joback and Reid8 was performed on 50 aliphatic compounds that were not used in the training set. The average absolute error for this method is approximately 20%, whereas that for the Joback and Reid data is 34%. The higher prediction accuracy of the proposed method suggests that the melting point prediction can better be approached by using both group contribution (enthalpic) and simple molecular geometric parameters (entropic).

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