Recovery of gossypol from cottonseed gums

A process has been developed for the isolation of pure gossypol from the gums obtained by water-washings of crude hexane-extracted cottonseed oil. Gums are heated with methyl ethyl ketone containing phosphoric acid to cleave gossypol-phosphatide reaction products and are cooled to separate a ketone phase containing the gossypol from a phosphatide-water phase. After concentration by distillation, gossypol is isolated from the methyl ethyl ketone concentrate by addition of glacial acetic acid to form the acetic acid addition compound of 92–94% purity. Two recrystallizations as the acetic-acid complex produce gossypol acetic acid of 99% purity. The purified product can be dissociated by solution in dilute sodium carbonate, from which pure gossypol is recovered by acidification with mineral acid.