Abstract
The effect of complex formation on the water-benzene interfacial transfer rate of barbital was studied. The transfer rate of barbital from aqueous to benzene phase was much accelerated by the addition of aminopyrine. The association constants of 1 : 1 barbital-aminopyrine complex in both phases were determined by solubility method. The constants in benzene and aqueous solutions at 30°C were 22.1 and 2.24 M-1, respectively. The best fitting equations for transfer data were numerically analyzed and it was clarified that the time course of the transfer rate of the complex was similar to that of free barbital and that the large value of the association constant in benzene solution resulted in the large transfer rate constant of the complex.
