Colloids and Surfaces
A: Physicochemical and Engineering Aspects 194 (2001) 97 – 110
The electrical conductance and viscosity of Nigerian
traditional soaps in alcoholic media
Moses O. Adebajo
a,
*, M. Sola Akanni
b
a
School of Chemistry, The Uniersity of New South Wales, Sydney NSW 2052, Australia
b
Department of Chemistry, Obafemi Awolowo Uniersity, Ile -Ife, Nigeria
Received 30 April 2001; accepted 30 April 2001
Abstract
The electrical conductances and viscosities of Nigerian traditional soaps in alcohols have been measured.
Potassium, sodium and potassium/sodium (50:1) soaps have been prepared from palm kernel oils using laboratory
prepared reagent alkalis and their conductances have also been measured. While the conductances vary with the
degree of purity of the soaps and the polarity of the solvents, the activation energy for conductance only varies with
the change of solvents. The conductances of the laboratory prepared potassium soaps are higher than those of the
sodium soaps, suggesting the metal ions to be the main charge carriers in solution. Plots of logarithm of conductivity
against inverse temperature are linear for all the soaps in methanol and ethanol while such plots are non-linear in
propan-1-ol in which the soaps are least soluble with lowest conductance values. However, the plot is linear for the
laboratory prepared potassium soap in propan-1-ol. The conductivities of the commercial (traditionally prepared)
soaps are found to be higher than those of the laboratory prepared ones, indicating the formation of soaps of many
fatty acid constituents of palm kernel oil in the traditional process of soap preparation. The variations of the
viscosities of the solutions with concentration, temperature and carbon chain length of the solvents are also discussed.
The plots of log
10
versus 1/T for all the soap solutions are linear suggesting that the solutions are non-associated
liquid systems in agreement with the conductance data. The variations of the activation energies obtained from these
plots with concentration and molecular weights of the solvents are discussed. The viscosity data are also interpreted
on the basis of Jones–Dole equation. The trend of the B -coefficient of this equation suggests that the soaps become
less ideal with increase in the molecular weights of the alcohols. The erratic nature of the A -coefficient values is again
related to the results of conductance measurement which indicate that the traditional method of soap preparation
produces mixed soaps and that the soaps contain many trace metal ions. © 2001 Elsevier Science B.V. All rights
reserved.
Keywords: Soaps in alcohols; Electrical conductance; Viscosity; Arrhenius and Eyring plots; Jones – Dole equation
www.elsevier.com/locate/colsurfa
* Corresponding author. Tel.: +61-2-93854683; fax: +61-
2-93856141.
E-mail address: funmi
–
adebajo@hotmail.com (M.O. Ade-
bajo).
1. Introduction
In our previous studies, various properties of
metal carboxylates (soaps) in the molten state
0927-7757/01/$ - see front matter © 2001 Elsevier Science B.V. All rights reserved.
PII:S0927-7757(01)00752-X