Studies of Zone Melting. IV. The Equilibrium Distribution Coefficient of the Bibenzyl–Stilbene System

Abstract

Abstract Determinations of the equilibrium distribution coefficients of stilbene in bibenzyl by the zone-melting method were performed by using the theory proposed by Burton and his co-workers from the effective distribution coefficients, which were measured at various zone travel rates (0.73, 0.98, 1.16, and 1.47 cm/h) on five samples of bibenzyl containing 0.3, 0.5, 1.0, 2.0, and 4.0 wt % of stilbene. Also, the equilibrium distribution coefficient independent of the concentration was obtained as 5.08 by the extrapolation of the equilibrium distribution coefficient vs. the concentration plots to zero concentration. The validity of the obtained results is discussed by a comparison of the values estimated individually by two other methods: the equilibrium distribution coefficient (5.23) determined from the phase diagram of the bibenzyl–stilbene system, and that (5.08) calculated thermodynamically.