| 摘要 |
Cis- and trans-ocimene and allo-dihydro-myrcene are made by the isomerization of myrcene and dihydromyrcene by contact with a catalytic amount of Rh, Ir, or a trihalide thereof, vat 60-165 DEG C. in the presence of HCl and optionally in the presence of an antioxidant. A catalytic amount is defined as 0.004-15% by wt. catalyst based on terpene. The catalyst may be supported on an inert carrier. The HCl may be added in the gaseous or aqueous form or may be contained in the catalyst as a result of an acid pre-treatment thereof. Specified antioxidants are 2, 6-di-t-butyl-4-methylphenol, 3-t-butyl-4-hydroxy-anisole, hydroquinone, the methyl ether thereof, and t-butyl-catechol. The process yields a mixture of the cis- and transisomers which may be separated by vapour phase chromatography.ALSO:Cis- and trans-ocimene, ocimenol, ocimenyl acylates, allo-dihydromyrcene, allo-dihydromyrcenol and allo-dihydromyrcenyl acylates, wherein the acyl group contains up to 4 carbon atoms, are prepared by isomerization of myrcene, myrcenol, myrcenyl acylates, dihydromyrcene, dihydromyrcenol or dihydromyrcenyl acylates by contact at 60-165 DEG C. with a catalytic amount of Rh, Ir or the trichlorides thereof in the presence of HCl and optionally in the presence of an antioxidant. A catalytic amount is defined as 0.004-15% catalyst by wt. of reactant. The catalyst may be supported on an inert carrier. The HCl may be added in the gaseous or aqueous form or the acid may be present in the catalyst as a result of an acid pretreatment thereof. Specified antioxidants are 2,6-di-t-butyl-4-methylphenol, 3 - t - butyl - 4 - hydroxy - anisole, hydroquinone, the methyl ether thereof and t-butylcatechol. Examples relate to the preparation of ocimene, ocimenol, ocimenyl acetate, allodihydromyrcene, and allo-dihydromyrcenol as cis-trans mixtures. The isomers may be separated by vapour phase chromatography. |
