Abstract
The interfacial processes between aqueous and organic phases for mass transfer of carboxylic acids were clarified using the cylindrical-lens schlieren apparatus. There existed no detectable interfacial resistance for acetic acid as a solute, while for n-valeric acid, interfacial resistance played an important role in the mass transfer. For the transfer of carboxylic acids, an equilibrium was attained between the concentration in the aqueous phase next to the interface and that at the interface. The process between organic phase and the interface was the rate-determining step among the processes associated with the interface. The interfacial resistance was found to originate from the resolvation process and the entropy effect of the solute transferring from the interface to the organic phase, the latter being affected by the number of CH2 groups in the solute molecule.
