Improvement to the processes of extraction, by chromatography, vitamin d2 previtamin d2

摘要

A process for the chromatographic extraction of Vitamin D2 or pro-Vitamin D2 prepared by the ultra-violet or ionizing irradiation of ergosterol, comprises (1) forming a solution of the mixture of irradiation products and unconverted ergosterol in a non-polar or weakly polar organic solvent; (2) passing the solution through fuller's earth which has been activated by eliminating at least a major part of the iron therefrom, followed by heating at a temperature of not more than 100 DEG C. and washing with an organic solvent; and (3) eluting Vitamin D2 and/or pro-Vitamin D2 from the fuller's earth with an organic solvent which is not less polar than the first solvent, whereby components of the mixture other than Vitamin D2 and proVitamin D2 remain adsorbed on the fuller's earth. The irradiation products may be dissolved in cyclohexane, carbon disulphide or normal hexane, and the Vitamin D2 and/or pro-Vitamin D2 may be eluted with carbon tetrachloride, cyclohexane or benzene. In an example fuller's earth is heated with concentrated hydrochloric acid, washed with water, heated at 40 DEG C. for 48 hours, washed with ethanol and cyclohexane; a solution in cyclohexane of products obtained by irradiating ergosterol with rays from cobalt 60 is passed through the fuller's earth and carbon tetrachloride is used for the elution.