dielectric and infrared studies of radio frequency processes in some alcohols
abstract
in this thesis, the results of dielectric studies on a number of aliphatic
alcohol molecules with variable chain lengths are presented. this investigation was
complemented by infrared and viscosity measurements. dielectric studies were
confined to the radio frequency range using an h.p. 419la rf inpedance analyzer.
the experimental data, as a function of frequency and temperature, were subjected to
analysis by a series of computer programs written in apl language. the activation
energy barriers for the dielectric relaxation were obtained by application of the
eyring rate equation.
initially, a number of pure liquid alcohol molecules were studied with
increasing chain length in a wide temperature and frequency range. the effect of
size on the relaxation parameters could then be revealed. in all cases a debye type
process was observed which is in accordance with the literature report
a few of these alcohols were also studied in a variety of solvents ranging
from inert to strongly interacting. the experimental relaxation times were compared
with the theoretical ones obtained using higasi's theory of the dielectric relaxation
mechanism. furthermore, the relaxation parameters were analysed in terms of
solute-solute and solute-solvent interactions.
the importance of chain length on the associative equilibria was examined.
methanol, which has no chain length and no intramolecular motion within the
experimental temperature and frequency ranges, was selected for this purpose. a
detailed dielectric study for this alcohol was carried out in different media.
an attempt was made to gain insight into the impact of steric hindrance on
the relaxation times and energy parameters. small alcohols were substituted by larger alcohol molecules in three component systems. the position of the dipole
was varied for different alcohols in two component systems. these studies
constitute the latter part of this thesis.
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