Process for lightening and stabilising the colour of fatty acids

摘要

The lightening and/or stabilising of the colour of fatty acid or fatty acid mixtures is effected by a vacuum distillation of the starting material to be purified with the addition of arylphosphorus sulphide. The starting material to be purified is preferably initially subjected to a thermal pretreatment at at least 150 DEG C under moderately reduced pressure. The amount of arylphosphorus sulphide which is then added is expediently not more than about 1 % of the weight of the distillation mixture. The concluding distillation is expediently carried out in the pressure range from 0.1 to 10 mbar.