Persistent Link:
http://hdl.handle.net/10150/184324
Title:
Solubility of aromatic compounds in mixed solvents.
Author:
Morris, Kenneth Robert.
Issue Date:
1988
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 solubilities of benzene, naphthalene and anthracene were measured in five binary solvent systems. These systems consised of water and one of the following water miscible organic solvents: acetone, acetonitrile, methanol, ethanol, and isopropanol. The measurements were made at intervals of 0.1 volume fractions of the organic cosolvent. Solubility data were also collected for the above solutes in mixed cosolvents. solvent systems containing three In addition, the solubilities of and six five other aromatic solutes were measured in the binary solvent systems of methanol/water and acetone/water. The data was used to test the log-linear solubility model of Yalkowsky (1981). The model predicts a linear relationship between the solubility of a solute in a binary solvent system (S(m)) and the volume fraction of cosolvent present (f(c)) log S(m) = σf(c) + log S(w) Where S(w) is the solubility of the solute in water and σ is the proportionality constant and slope of the curve. The model is easily extended to multiple mixed solvents by combining the σ values from the binary solvent systems. log (S(m)/S(w)) = Σ₁ (σ₁£₁) A method was developed to estimate σ in a given binary solvent system from the octanol-water partition coefficient of the solute. Combining this method with the generalized solubility equation of Yalkowsky to estimate S(w), allows a priori estimates of solubility in mixed solvents. Maximum deviations in the binary solvent systems studied were related to maxima in excess density. In the alcoholic binary solvent systems the minima were related to minima in the heats of mixing of the two cosolvents. The herbicide atrazine deviated dramatically from the model. The system was examined for possible changes in the crystal structure of atrazine. It was found that some crystal modification occured in the presence of mixed solvents. The rate of the change appears to be dependant on the concentration of the cosolvent. A change or modification in the crystal violates one of the basic assumptions of the log-linear model. The assumption is that the crystal contributes equally to the solubility behavior irrespective of the solvent system. It was determined that atrazine undergoes a polymorphic transition in the systems studied. It is postulated that this polymorphism is responsible for the anomolous solubility behavior observed for atrazine.
Type:
text; Dissertation-Reproduction (electronic)
Keywords:
Aromatic compounds -- Solubility.; Benzene -- Solubility.; Naphthalene -- Solubility.; Anthracene -- Solubility.
Degree Name:
Ph.D.
Degree Level:
doctoral
Degree Program:
Pharmaceutical Sciences; Graduate College
Degree Grantor:
University of Arizona

Full metadata record

DC FieldValue Language
dc.language.isoenen_US
dc.titleSolubility of aromatic compounds in mixed solvents.en_US
dc.creatorMorris, Kenneth Robert.en_US
dc.contributor.authorMorris, Kenneth Robert.en_US
dc.date.issued1988en_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 solubilities of benzene, naphthalene and anthracene were measured in five binary solvent systems. These systems consised of water and one of the following water miscible organic solvents: acetone, acetonitrile, methanol, ethanol, and isopropanol. The measurements were made at intervals of 0.1 volume fractions of the organic cosolvent. Solubility data were also collected for the above solutes in mixed cosolvents. solvent systems containing three In addition, the solubilities of and six five other aromatic solutes were measured in the binary solvent systems of methanol/water and acetone/water. The data was used to test the log-linear solubility model of Yalkowsky (1981). The model predicts a linear relationship between the solubility of a solute in a binary solvent system (S(m)) and the volume fraction of cosolvent present (f(c)) log S(m) = σf(c) + log S(w) Where S(w) is the solubility of the solute in water and σ is the proportionality constant and slope of the curve. The model is easily extended to multiple mixed solvents by combining the σ values from the binary solvent systems. log (S(m)/S(w)) = Σ₁ (σ₁£₁) A method was developed to estimate σ in a given binary solvent system from the octanol-water partition coefficient of the solute. Combining this method with the generalized solubility equation of Yalkowsky to estimate S(w), allows a priori estimates of solubility in mixed solvents. Maximum deviations in the binary solvent systems studied were related to maxima in excess density. In the alcoholic binary solvent systems the minima were related to minima in the heats of mixing of the two cosolvents. The herbicide atrazine deviated dramatically from the model. The system was examined for possible changes in the crystal structure of atrazine. It was found that some crystal modification occured in the presence of mixed solvents. The rate of the change appears to be dependant on the concentration of the cosolvent. A change or modification in the crystal violates one of the basic assumptions of the log-linear model. The assumption is that the crystal contributes equally to the solubility behavior irrespective of the solvent system. It was determined that atrazine undergoes a polymorphic transition in the systems studied. It is postulated that this polymorphism is responsible for the anomolous solubility behavior observed for atrazine.en_US
dc.typetexten_US
dc.typeDissertation-Reproduction (electronic)en_US
dc.subjectAromatic compounds -- Solubility.en_US
dc.subjectBenzene -- Solubility.en_US
dc.subjectNaphthalene -- Solubility.en_US
dc.subjectAnthracene -- Solubility.en_US
thesis.degree.namePh.D.en_US
thesis.degree.leveldoctoralen_US
thesis.degree.disciplinePharmaceutical Sciencesen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.grantorUniversity of Arizonaen_US
dc.identifier.proquest8809943en_US
dc.identifier.oclc20061449en_US
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