Part 1: The determination of activity coefficients at infinite dilution ; Part 2: Investigations into the colour components of raw sugar.

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.