Chemical Properties
3-trans-Isocamphylcyclohexanol is the component responsible for the sandalwood odor of
a synthetic mixture of terpenylcyclohexanol isomers. A commercially available
mixture containing 3-trans-isocamphylcyclohexanol is prepared by reacting
camphene and guaiacol in the presence of an acidic catalyst (e.g., boron trifluoride),
followed by catalytic hydrogenation of the resulting terpenylguaiacols. In
the alkylation reaction, camphene rearranges to the isobornyl, isofenchyl, and
isocamphyl skeletons. These substituents may be introduced in guaiacol at four
positions. In the subsequent hydrogenation with simultaneous elimination of the
methoxy group, additional possibilities for isomerism arise because the hydroxy
group may be either axial or equatorial to the terpenyl moiety. Therefore, the
actual content of the desired isomer, 3-trans-isocamphylcyclohexanol, is low in
most products.The other isomers are either weak in odor or odorless.
A process starting from catechol, instead of guaiacol, yields a mixture with a
higher content of 3-trans-isocamphylcyclohexanol, especially if the hydrogenation
of the terpenylcatechols is carried out continuously under high pressure
on a cobalt catalyst.
Themixture is used as such in large amounts as a fixative with sandalwood odor
in a broad range of fragrances.
