The distillation of vitamin D

Abstract

A method is described for the partial separation of the irradiation products of ergosterol, by distillation and fractional condensation in a high vacuum. By double distillation, followed by crystallisation from aqueous alcohol, a crystalline product has been obtained, showing high antirachitic power, and a melting point of 113[degree] to 115[degree] C. It is not suggested that these crystals are pure vitamin D. They may consist of an inactive substance contaminated with an extremely active vitamin, or of crystalline vitamin forming mixed crystals with an inactive substance. It is possible, on the other hand, that several antirachitic substances are formed by the irradiation of ergosterol, and that the crystals are a relatively pure specimen of one of these substances. Some evidence is given as to the degree of efficiency of the process of fractional condensation in a high vacuum.