Abstract
Vitamin A aldehyde was obtained as yellow crystals from MnO_2 treated natural vitamin A concentrates. From the reaction with maleic anhydride and an infra-red spectrum, it is reasonable to believe that the crystals would have all-trans configuration. Various other properties are well agreed with those reported by others. The stability of the aldehyde against oxidation was rather higher than the stabilities of vitamin A alcohol and vitamin A acetate. A color formed by the addition of SbCl_3 reagent was also found to be more stable than with the two latter.
