Sulfuric Acid → 3-Methylnonan-1-ol

Participants

Reaction Steps

The 3-methyl-2-nonen-1-ol employed in the perfume compositions of this invention and as a reactant in the production of monocarboxylic acid esters of that alcohol is produced by employing 3-methyl-1-nonen-3-ol as the starting material. The starting alcohol is reacted in the absence of solvents with a monocarboxylic acid such as acetic acid together with sulfuric acid and maintained at a temperature of about 50° to 80° C. The progress of the reaction is followed by I.R. spectroscopy. Under these conditions there is dehydration of the tertiary alcohol, 3-methyl-1-nonen-3-ol to a hydrocarbon, allylic rearrangement of the tertiary alcohol to the primary alcohol, 3-methyl-2-nonen-1-ol and partial esterification with formation of a monocarboxylic acid ester of 3-methyl-2-nonen-1-ol. A solution of an alkali metal hydroxide, such as sodium hydroxide and a suitable solvent such as methanol is added to the reaction product and the solution refluxed for three to six hours to saponify the esters. The solvent is removed by distillation under a slight vacuum. The remaining reaction product is then washed successively with water, an alkali metal bicarbonate solution and water. Fractional distillation under vacuum is conducted to obtain a fraction containing the 3-methyl-2-nonen-1-ol. The fraction distilling at 10 mm and a temperature of 110°-111° C. is recovered and contains primarily the 3-methyl-2-nonen-1-ol. The corresponding saturated alcohol, 3-methylnonan-1-ol is produced by hydrogenation of the unsaturated alcohol 3-methyl-2-nonen-1-ol in the presence of Raney nickel or other suitable catalyst.

Provenance & Evidence