THESIS
2004
xv, 120, [16] leaves : ill. (some col.) ; 30 cm
Abstract
Crystallization has been widely used for product separation and purification in the pharmaceutical, chemical and food industries because of its ability in producing extremely pure solid compounds. To reduce the time, cost and risks in designing and synthesizing crystallization-based processes, a number of systematic procedures have been developed. However, the basis of these systematic procedures necessitates the acquisition of the solid-liquid equilibrium (SLE) phase diagrams of the chemical systems under consideration, which are often not available in the literature. There is thus a great demand for determining SLE phase diagrams through experimental means....[
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Crystallization has been widely used for product separation and purification in the pharmaceutical, chemical and food industries because of its ability in producing extremely pure solid compounds. To reduce the time, cost and risks in designing and synthesizing crystallization-based processes, a number of systematic procedures have been developed. However, the basis of these systematic procedures necessitates the acquisition of the solid-liquid equilibrium (SLE) phase diagrams of the chemical systems under consideration, which are often not available in the literature. There is thus a great demand for determining SLE phase diagrams through experimental means.
This work aims at developing experimental apparatus and techniques to construct the isobaric SLE phase diagrams of various organic-based chemical systems. The major technique is based on the solid-disappearance method, in which a point on the saturation boundary is determined by detecting visually the temperature at which the last trace of solid in the sample mixture disappears. To provide auxiliary information for the phase diagrams and to check the accuracy of the temperature data, crystals are also sampled by suction filtration from mixtures of selected composition and analyzed for identities using techniques such as HPLC and IC.
To demonstrate the experimental technique and its reliability, the isobaric SLE phase diagrams of three systems are determined. The first one is an organic system containing phenol, bisphenol A and water. In the second example, the isobaricisothermal SLE phase diagram of the system composing both organic and inorganic species of succinic acid, diammonium succinate, water, ammonium hydroxide, sulfuric acid and ammonium sulfate are constructed at 25°C. The last system is a binary system involving sulfamerazine, a polymorphic drug, and dimethyl sulfoxide. The resulting SLE phase diagrams of these systems are found to be in a high degree of accuracy and from which the saturation regions of several targeted species such as bisphenol A and succinic acid are identified.
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