Phenylisohexanol is a synthetically made organic compound, used as a rose smell fragrance at industrial scale. The substance is also known under the brand names: phenoxanol (International Flavors & Fragrances), mefrosol (Givaudan, formerly Quest International), and phenylhexanol (Firmenich).
Properties Phenylisohexanol occurs as a clear, colorless to light yellow liquid and has a fresh rose oil scent that lingers long after use. Phenylisohexanol is a primary alkyl aryl alcohol and is chemically related to citronellol. However, the isobutenyl group from citronellol is replaced by a phenyl group. The odor detection threshold of phenylisohexanol is approximately 0.8 µg /m³, ten times lower than that of citronellol.
Synthesis The starting materials for the synthesis of phenylisohexanol are isoprene and benzaldehyde. The oxo-Diels–Alder reaction between the two components forms 2-phenyl-4-methyl-3,6-dihydropyrane (CAS number 60335-71-9), also known as rosyran. Ring opening by hydrogenolysis in acidic center of the dihydropyrane ring yields racemic phenylisohexanol.
The commercial product is a racemic mixture of the two stereoisomers, (R)-(+)- and (S)-(-)-phenylisohexanol. With asymmetric synthesis, it is possible to produce the R- or S- isomer separately.
Usage Phenylisohexanol is used in cosmetics, perfumes, and deodorants, among other applications.
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