Collect. Czech. Chem. Commun. 1985, 50, 704-711

Approximate relations for determining the activity coefficient at very low concentration by the method of variation of solute concentration

Bohuslav Doležal and Robert Holub

Department of Physical Chemistry, Prague Institute of Chemical Technology, 166 28 Prague 6


The calculation of activity coefficients at very low concentration is described from the experimental data obtained by the method of the variation of solute concentration for a way of saturation with ensured sufficiently long contact time of the liquid and gas phases and intensive stirring of both phases when the amount of the observed component in the vapour phase above the solution is negligible with regard to its content in the liquid phase. Two variants of experimental procedure were considered: stripping by a pure inert gas and by a gas saturated with solvent vapours. The relations derived can be used either directly for computer calculations or on introducing some simplifying assumptions for a rapid manual calculation with a good agreement of the results.