AbstractsChemistry

The umbellulone was isolated from the myrtle oil by the sulfite method, which was found to be the most inexpensive and convenient method of obtaining the pure ketone. The umbellulone was hydrogenated in the vapor phase over a nickel catalyst, passing it through an electric tube furnace, in an attempt to compare the course of the reduction with that obtained by previous investigators operating upon a liquid phase. The products of each hydrogenation at different temperatures from 250° to 375°C. were analyzed for ketone, alcohol, and phenol contents, and for iodine value to determine unsaturation. Their physical constants, including specific gravity, optical rotation, and refractive index were also determined. The results so obtained were compared with those of the original ketone used and the following conclusions were shown:- 1. At temperatures below 300°C. partially saturated hydrogenated compounds were obtained. 2. At higher temperatures rearrangement took place converting umbellulone into phenols, specifically thymol. 3. The relative increase in alcohol content with a decrease in ketone content is probably due to a conversion of a dihydroumbellulone, which is first produced, to dihydroumbellulol or the fully saturated tetrahydroumbellulol, or possibly in part to the formation of menthone and its conversion to menthol.