THE DISTILLATION, EXTRACTION, AND CHROMATOGRAPHIC SEPARATION OF THE C2–C8 FATTY ACIDS

Thirty-five milliliters of an aqueous solution containing 5 to 70 micromoles of volatile C2 to C8 acids was distilled to constant volume without refluxing. The distillate was titrated, made alkaline, and evaporated to dryness at 110°C. The free acids were regenerated by the addition of 0.03 ml. of 10 N sulphuric acid, absorbed on filter paper, and extracted quantitatively with 3 ml. of chloroform–butanol (99: 1). Acids present in the extract were separated by chromatography on a composite silica-gel column employing two internal indicators, and after elution were determined by titration, the details for which are given. The preparation of a reproducible silica is described.