GB690879A - Process for the isolation of cholesterol from wool-wax alcohols - Google Patents

Abstract

Cholesterol and isocholesterol are separated from wool-wax alcohols by first crystallizing the isocholesterol from a solution of the raw product in a mixture of benzene or its lower homologues (e.g. toluene or xylene) and methanol (the proportion of the latter preferably being between 40 and 80 per cent by volume), and thereafter separating the cholesterol from wax-like impurities by selective crystallization from, or selective dissolution of the impurity by, a simple fatty acid (e.g. acetic or propionic acid) under carefully regulated temperature conditions over the range of 27-45 DEG C. (preferably about 30-35 DEG C.). Advantageously the initial solution is prepared from wool-wax alcohols melted at about 60 DEG C. and dissolved in 2 1/2 volumes of the mixed solvent, and is seeded with isocholesterol and cooled gradually to about 20-30 DEG C., thereby ensuring the formation of relatively large crystals of isocholesterol and facilitating the separation thereof by filtration, which step is followed by evaporation of the solvent to provide the starting material for the final fractionation step. The cholesterol obtained thereby may be further purified by recrystallization from alcohol (e.g. industrial methylated spirit). Examples illustrate the use of the solvents specified above under various conditions.