19. Dubbs, Michael D.; Gupta, Ram B.. Solubility of Vitamin E (a-Tocopherol) and Vitamin K3 (Menadione) in Ethanol-Water Mixture. J. Chem. Eng. Data (1998), 43(4), 590-591.
Phase behavior of vitamins in aq. solns. is important in chem. processing and medical and dietary applications. Soly. is reported for two fat-sol. vitamins, vitamin E (a-tocopherol) and vitamin K3 (menadione), in aq. mixts. contg. ethanol at 33°. Both vitamins have very low soly. in pure water owing to hydrophobic repulsion. Addn. of ethanol in the water results in a large increase in soly., mostly due to nonpolar attractive interactions between ethanol and vitamin mols. For example, by addn. of 70 mass % ethanol, vitamin E soly. increases 450-fold and vitamin K3 soly. increases 170-fold. The enhancement is more pronounced with vitamin E because it is more hydrophobic than vitamin K3.