An improved procedure for the purification of gossypol

Summary Methods of dissociating the gossypol‐acetic acid complex prepared from the butanone extract of defatted cottonseed flakes and methods of recrystallizing gossypol were studied. The study led to the development of an improved rapid procedure for the purification of gossypol. In this procedure gossypol‐acetic acid is dissociated with aqueous sodium hydroxide containing sodium hydrosulfite; the gossypol is precipitated with hydrochloric acid, extracted with ether, and recrystallized from a mixture of ether and xylene. Two crystallizations by this procedure gave gossypol free from acetic acid and of a high degree of purity. Gossypol‐acetic acid of a high degree of purity was prepared by a modification of this procedure. The degree of purity of the gossypol prepared by the improved procedure was determined by a number of tests, which are described. Spectral and titration curves for pure gossypol are presented, and standards of purity are suggested. The molecular weight of gossypol and gossypolacetic acid prepared by the procedures described is approximately 518 and 578, respectively.