GB704079A - Improvements relating to the purification of chlortetracycline - Google Patents

Abstract

An improvement in or modification of the process of purifying crude chlortetracycline also known as aureomycin according to the parent Specification comprises extracting chlortetracycline, preferably at a temperature not exceeding 55 DEG C., from an aqueous acidic solution of crude chlortetracycline at a pH of 1 to 3 with butanol whereby an aqueous layer and a butanol layer are formed, assisting the extraction by adding a water-soluble salt, preferably sodium chloride, which is dissolved in the aqueous layer, and recovering chlortetracycline from the butanol layer. The butanol layer may be concentrated in vacuo below 50 DEG C., and the chlortetracycline so obtained washed with ethanol, water and again ethanol, or other solvents may be used. The aqueous acidic solution of chlortetracycline may be the filtrate obtained after treating an acid solution of crude chlortetracycline with decolorizing carbon, or may be derived from a fermentation mash by any suitable treatment such as (a) acidification of the mash, filtration and concentration of the filtrate in vacuo below 50 DEG C., and (b) treating the mash with alkali such as calcium hydroxide, filtering off the solids and extracting the solids with mineral acid. Other salting out agents are sodium iodide, sodium bromide, barium chloride, sodium sulphate, ammonium sulphate, potassium sulphate, potassium chloride, magnesium sulphate, sodium oxalate, ammonium chloride and triethylamine hydrochloride.