An improved method for the purification of folic acid

Autor: B. I. Demchenko, M. S. Belyakova, A. F. Anshakov, B. V. Shemeryankin, L. A. Gorbunkova
Rok vydání: 1976
Předmět:
Zdroj: Pharmaceutical Chemistry Journal. 10:1092-1094
ISSN: 1573-9031
0091-150X
DOI: 10.1007/bf00758105
Popis: METHOD The technical product (10 g) was dissolved in i000 ml of dilute hydrochloric acid which was first warmed to 50 ~ . The solution was then cooled without stirring for 2 h to 35-40 ~ , followed by cooling to 0-2 ~ with intermittent stirring. The folic acid which separated in the precipitate was filtered off and washed free from chlorides with water. Destruction of folic acid in hydrochloric acid solution increases with increasing concentration of hydrochloric acid, and with the temperature of heating. It became clear from preliminary experiments that it was desirable to use hydrochloric acid within the concentration limits of 2-5% for the recrystallizatio n of the technical product. It follows from Table i that the optimum results from the point of view of the yield and purity of the folic acid were obtained by using 5% hydrochloric acid. The lower yields of purified folic acid obtained when 2% hydrochloric acid was used were attributed to the higher solution temperature. In comparison with the previous standard method of purification, recrystallizatio n from dilute hydrochloric acid enables the rate of filtration and washing to be increased by several times, and the loss of material to be reduced. The principal advantage of the new method of acid purification is that the formation and growth of the crystals takes place in a homogeneous solution with a gradual reduction in the solubility of the folic acid and reduction in the temperature of the solution. When the compound is precipitated from solution in concentrated hydrochloric acid by dilution with water, a rapid decrease in the solubility of the folic acid occurs, accompanied by the formation of very fine crystals. A reduction in the rate of addition of water in the dilution of the hydrochloric acid does not result in any appreciable increase in the size of the crystals, since growth of the crystals occurs not in the total volume of the solution, but in the localized regions in which the water mixes with the hydrochloric acid.
Databáze: OpenAIRE
Externí odkaz: