Riboflavin結晶の工業的製造に關する研究 (第6報) : B_2 粗結晶精製法の檢討
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概要
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The crude riboflavin products, which were produced by cultivation of Eremothecium Ashbyii in the medium consisting of embryo, even after extraction with hot water, precipitation with reducing agent and recrystallization from dilute acetic acid, contain still some impurities.The present author studied on the purification method of the crude riboflavin products by paper chromatography in order to examine the presence or absence of the impurities in the crystals obtained by various methods.Generally, crude products showed several spots on paper chromatograms devel oped with the upper layer of mixture of n-butanol-acetic acid-water (4 : 1 : 5) Each spot can be detected by its fluorescence in ultra-violet ray.When the purification was carried out by recrystallization from water, hrdrochloric acid or acetic acid, the spots having smaller Rf values than riboflavin disappeared.The almost same results were obtained by reprecipitation from the solution in concentrated hydrochloric acid, too.The spots having larger Rf values than riboflavin and the spot having Rf 0.27 disappeared by extraction of the impurities with chloroform or benzene.Therefore, the purification method is expected to be complete, when the recrystallization or the reprecipitation and the extraction are combined. But the melting points and the degree of purity of riboflavin crystal, which was purified by these combined methods and seemed to be pure by paper chromatography, were still a little lower than those of extra pure crystal.It is considered that this difference is due to a very small amount of unidentified non-fluorescent impurities, which are contained in the crystal obtained and can not be detected by fluorescence method.The sample is dissolved in concentrated hydrochloric acid and hydrogen peroxide is added. After a while it is filtered, and the filtrate is shaken with chloroform for removing impurities, searated from chloroform layer and then diluted with water.The precipitate thus produced is recrystallized from hot water.
- 1951-02-15