6,8-dimethylnona-3,5-dien-2-one → 6,8-Dimethylnonan-2-ol

Participants

Reaction Conditions

Reaction Steps

200 g of freshly distilled 6,8-dimethyl-3,5-nonadien-2-one and 2 g of copper chromite are placed in a 1 liter steel autoclave which is provided with a magnetic stirrer (Autoclave Engineers, Inc.). The autoclave is flushed with hydrogen and it is firstly placed under a pressure of 30 bar of hydrogen. The autoclave is now heated rapidly to 100° C. and then slowly within 3 hours to 170° C. The pressure is then adjusted to 50 bar and the temperature is fixed at 200° C. The theoretical amount of hydrogen to be absorbed amounts to 90 liters. The autoclave is held at a pressure of 50 atmospheres and in a temperature range between 180°-200° C. After 5 hours, 7% of unsaturated material is still present in the mixture. The hydrogenation is continued for a further 6 hours in order to reduce the amount of non-hydrogenated product to 0.2%. The resulting crude product is separated from the catalyst by filtration and then distilled. There are obtained 171 g (83%) of chemically pure 2,4-dimethyl-nonan- 8-ol of boiling point 91° C./6 mmHg; nD20 =1.4368. 136 g of this product are designated at being olfactorily good (yield 83% or 65.7% respectively).

Provenance & Evidence