Part 1: The determination of activity coefficients at infinite dilution ; Part 2: Investigations into the colour components of raw sugar.
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Date
1996
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Abstract
PART I:
This work is part of an investigation to determine activity coefficients at
infinite dilution (1'73) of hydrocarbons dissolved in the industrially important
polar solvent tetrahydrothiophene-l, l-dioxide (sulfolane), by medium pressure gas liquid chromatography (g.l.c.). In this work the activity coefficients at infinite dilution for a series of l-alkenes (C6-CS) , l-alkynes (C6-CS) , and cycloalkanes (C7 and Cs) have been measured in the polar solvent, sulfolane, at 303.15 K and 313.15 K. The activity coefficients of some of the solutes
discussed in this work would be difficult to determine by any other method
because of their low solubility in sulfolane. The mixed second virial coefficients
used in this work were determined assuming the principle of corresponding
states, the Hudson and McCoubrey combining rules for T~2' the Lorentz rule
for V~2' and the McGlashan-Potter equation.
PART II:
Unrefined sugar contains organic colour material originating In the
sugarcane or formed during the extraction and purification processes. Sugar
colour must be within the limits of acceptability for direct or indirect
consumption. In this work, a cost effective technique to separate colourants
from sugar through a sucrose packed medium pressure chromatographic column
was investigated. Three dimensional perspective plots of
wavelength/absorbance/time were developed to provide insight into the nature
of the sugar colourants and to provide a means of investigating various
decolourisation systems.
In addition to the above experiment a procedure was developed to
remove colourant species from unrefined sugar samples and from samples taken
during the refining process for chemical analysis. In this work only one
technique - gas chromatography-mass spectroscopy was used to identify the
species.
Description
Thesis (M.Sc.)-University of Natal, Durban, 1996.
Keywords
Activity coefficients., Gas chromatography., Hydrocarbons., Sugar--Analysis., Theses--Chemistry.