1960 年 80 巻 1 号 p. 95-98
Formation of a complex between the solubilizate and a solubilizing agent, the acid amides, in aqueous or alcoholic solution was further confirmed by measurement of partition coefficient, and a relationship between increased solubility of a solubilizate by the use of a solubilizing agent and formation of a complex was examined with salicylamide and nicotinamide. Measurement of partition coefficient of nicotinamide and salicylamide between benzene and water showed that nicotinamide is present only in the water phase and does not transfer to the benzene phase, while the coefficient of salicylamide to benzene/water=1.265 at 25°C. Apparent partition coefficients in a solution containing both nicotinamide and salicylamide showed that the amount of salicylamide is constant in benzene phase while its amount in water phase was found to increase in proportion to the amount of nicotinamide. Since it is known that salicylamide and nicotinamide form a complex in solution, this increase can be attributed to the formation of a complex and calculation of equilibrium constant of the equilibrium system of complex formation from partition coefficient gave a constant value, satisfying the equilibrium system and agreeing with the law of partition.