Study on the Reaction of Higher Fatty Acid Esters with Metallic Sodium. V. Preparation and Properties of ƒ¿-Glycols

The C12•`C36 sym. ƒ¿-glycols were prepared from acyloins by catalytic hydrogenation with Raney nickel. The properties of ƒ¿-glycols were studied. Melting point of the ƒ¿-glycol is higher than that of the corresponding acyloin or ƒ¿-diketone and decreases with chain length. Two hydroxyl groups can be quantitatively acetylated by acetic anhydride, and reacted with 3, 5-dinitrobenzoyl chloride to give the crystalline 3, 5-dinitrobenzoate. From mp and optical rotation of fractional crystals, ƒ¿-glycols obtained by catalytic hydrogenation seem to consist of meso or racemic form. In the acetic acidical solution ƒ¿-glycols are quantitatively oxidized with periodic acid as well as ethylene glycol, and in the 99% alcoholic solution the oxidation by periodic acid is quite the same as acyloins. When heated to 200•Ž, these ƒ¿-glycols are hard to change into ketones by dehydration. ƒ¿ -Glycols show the broad absorption band in the range of 2.29•`3.01ƒÊ assigned to associated hydroxyl groups, and complicated bands of C-O stretching in the range of 8•`10ƒÊ.