In the previous studies of this series, it was investigated the influence of water content on the change of vitamin A acetate and its changed products in aqueous ethanolic solution. This report describes the results of a similar study on the stability of vitamin A alcohol, an intermediate product of vitamin A acetate in aqueous ethanolic solution. Remaining rate of commercial vitamin A alcohol (contain antioxidants) and purified vitamin A alcohol (antioxidant free) were determined by UV spectrophotometric method and f-values were compared respectively. The amount of changed products of purified vitamin A alcohol were examined by alumina column chromatography and thin layer chromatography. The stability of vitamin A alcohol in 60〜100% ethanolic solutions at 35°, 50°and 100℃ decreased gradually as water increased. Five substances were recognized as changed products of vitamin A alcohol. (a) Anhydro vitamin A (R_F 0.67), (b) vitamin A ethyl ether (R_F 0.55), (c) vitamin A aldehyde (R_F 0.32), (d) unknown (R_F 0.05), (e) vitamin A acid (R_F 0.03). Especially physical property of vitamin A ethyl ether was examined by UV, IR, NMR and mass spectrometry. Although anhydro vitamin A were recognized as the changed products of purified vitamin A alcohol, retro vitamin A and its changed products were not recognized.
