Water → Biotin

Participants

Reaction Steps

320 g of crude dibenzylbiotin (containing about 80% of pure dibenzylbiotin, 0.60 mol) are mixed with 125 g of water, and 500 g of sulfuric acid are carefully added with stirring at such a rate that the temperature of the batch does not exceed 115° C. Stirring is then continued at 115° C. for 3 hours. 2.5 l of xylene are added, and the mixture is then firstly neutralized using 5 l of 9% sodium hydroxide solution and then rendered alkaline. The aqueous phase is separated off. The xylene phase is extracted twice more with 0.5 1 of 9% sodium hydroxide solution in each case. The aqueous phase and the sodium hydroxide phases from the post-reactions are combined and adjusted to a pH of 6 at 80° C. using sulfuric acid. 12 g of activated carbon are added, the mixture is subjected to a polishing filtration, and the pH is slowly reduced to 1.5 using sulfuric acid. After the mixture has been cooled overnight, the precipitated biotin is filtered off with suction and dried, giving 128 g of biotin (content: about 99%, corresponding to 126 g of pure biotin=0.52 mol, 86% of theory).

Provenance & Evidence