Persistent Link:
http://hdl.handle.net/10150/288729
Title:
Estimating the entropy of melting from structure
Author:
Dannenfelser, Rose-Marie, 1959-
Issue Date:
1997
Publisher:
The University of Arizona.
Rights:
Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
Abstract:
The total entropy of melting for a wide variety of compounds is estimated by a modification of Walden's rule. This modification accounts for the effects of both molecular rotational symmetry and molecular flexibility on entropy. These effects are combined into a single simple semi-empirical equation. The intercept of the equation was modified from Walden's rule (56.5 J/K·mol), which uses a small data set, to 50 J/K·mol, which uses a data set of 237 rigid and asymmetrical molecules. The molecular rotational symmetry number, σ, and molecular flexibility number, φ, are separately defined and evaluated for a wide variety of molecules and are shown to be related to the entropy of melting in Chapters II and III, respectively. The two effects are combined so that a single equation can be used to predict the entropy of melting for any nonelectrolyte compound. This semi-empirical equation is tested on an independent data set. For over 930 different molecules, including those which are both rigid and flexible, the average absolute error between the predicted and observed entropy of melting values is only 12.5 J/deg·mol. This difference is within experimental error.
Type:
text; Dissertation-Reproduction (electronic)
Keywords:
Chemistry, Analytical.; Chemistry, Pharmaceutical.; Chemistry, Physical.
Degree Name:
Ph.D.
Degree Level:
doctoral
Degree Program:
Graduate College; Pharmaceutical Sciences
Degree Grantor:
University of Arizona
Advisor:
Yalkowsky, Samuel H.

Full metadata record

DC FieldValue Language
dc.language.isoen_USen_US
dc.titleEstimating the entropy of melting from structureen_US
dc.creatorDannenfelser, Rose-Marie, 1959-en_US
dc.contributor.authorDannenfelser, Rose-Marie, 1959-en_US
dc.date.issued1997en_US
dc.publisherThe University of Arizona.en_US
dc.rightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.en_US
dc.description.abstractThe total entropy of melting for a wide variety of compounds is estimated by a modification of Walden's rule. This modification accounts for the effects of both molecular rotational symmetry and molecular flexibility on entropy. These effects are combined into a single simple semi-empirical equation. The intercept of the equation was modified from Walden's rule (56.5 J/K·mol), which uses a small data set, to 50 J/K·mol, which uses a data set of 237 rigid and asymmetrical molecules. The molecular rotational symmetry number, σ, and molecular flexibility number, φ, are separately defined and evaluated for a wide variety of molecules and are shown to be related to the entropy of melting in Chapters II and III, respectively. The two effects are combined so that a single equation can be used to predict the entropy of melting for any nonelectrolyte compound. This semi-empirical equation is tested on an independent data set. For over 930 different molecules, including those which are both rigid and flexible, the average absolute error between the predicted and observed entropy of melting values is only 12.5 J/deg·mol. This difference is within experimental error.en_US
dc.typetexten_US
dc.typeDissertation-Reproduction (electronic)en_US
dc.subjectChemistry, Analytical.en_US
dc.subjectChemistry, Pharmaceutical.en_US
dc.subjectChemistry, Physical.en_US
thesis.degree.namePh.D.en_US
thesis.degree.leveldoctoralen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.disciplinePharmaceutical Sciencesen_US
thesis.degree.grantorUniversity of Arizonaen_US
dc.contributor.advisorYalkowsky, Samuel H.en_US
dc.identifier.proquest9806833en_US
dc.identifier.bibrecord.b37557038en_US
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