Abstract: The invention is a method for recovering azelaic acid from a mixed oxidation product by prepurifying the azelaic acid and introducing the prepurified azelaic acid into the central portion of a dual countercurrent extraction column operated at an elevated temperature and introducing an aqueous phase into the top of the extraction column and a water immiscible solvent for the monocarboxylic acids in the prepurified azelaic acid into the bottom portion of the extraction column and recovering the purified azelaic acid from the aqueous phase. The azelaic acid can be recovered from the aqueous phase by drying the aqueous phase and separating a low boiling fraction and a high boiling fraction from the azelaic acid product by distillation.

Abstract: The invention is a method for improving the color and color stability of oleic acid by a two column distillation process in which the oleic acid to be color improved is introduced into a first distillation zone containing an enriching section and a stripping section providing a minor amount of a topping product and a major amount of underflow containing the oleic acid and passing the oleic acid to a bottom portion of a second distillation zone having an enriching section to recover the improved oleic acid with improved color and color stability as a top product from the second distillation zone.