Dehydronerolidol: Properties, Production process and Uses
Properties of Dehydronerolidol
Dehydronerolidol, also known as 3,7,11-trimethyldodeca-6,10-dien-1-yn-3-ol, is a derivative of geranyl acetone. CAS Registry Number: 2387-68-0. Molecular formula: C15H24O, molecular weight: 220.3505. The chemical structure is:
Dehydronerolidol is a colorless and transparent liquid having a boiling point of 318.5°C (101.3 kPa), a flash point of 289.8°C, a refractive index of 1.49 (25°C) and a density of 0.902 g.cm–3.
Production process of Dehydronerolidol
In the presence of an alkali metal hydroxide catalyst, geranyl acetone reacted with acetylene under atmospheric pressure to form dehydronerolidol with a yield of 85.7%. The reaction equation is as follows:
The alkali metal hydroxide, usually a fine and uniform powdered potassium hydroxide, is dispersed in the organic phase. Potassium hydroxide is in excess of the raw material geranyl acetone. The solvent type has a great influence on the reaction, and a solvent such as toluene or tetrahydrofuran can be used. Among them, tetrahydrofuran has the best solvent effect because acetylene has a large solubility in tetrahydrofuran, and solid potassium hydroxide can be dissolved and dispersed well in it. If no solvent is introduced, the reaction system will be thick and uneven, resulting in the production of significant amounts of by-products and thus a low yield of the target product dehydronerolidol. The water in the solvent is unfavorable to the ethynylation reaction, so it should be removed before use.
In general, the reaction is carried out for 4–8h at a temperature between 0 and −5°C. At low temperature, the solubility of acetylene in the reaction system is relatively large, which is favorable to the enhancement of geranyl acetone conversion. Moreover, the selectivity to dehydronerolidol is higher and the by-products are fewer at low temperature. As the reaction temperature is raised to room temperature or higher, the by-products are significantly increased.
Uses of Dehydronerolidol
Dehydronerolidol is mainly applied to production of nerolidol by partial reduction of the acetylenic bond in its molecule.
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