Study On The Catalysts For The Synthesis Of Perilla Alcohol By Liquid Phase Isomerization Of 2,10-Epoxypinane

Liquid phase isomerization of 2,10-epoxypinane is the simplest method for the synthesis of perilla alcohol (POH) in the reported literatures. POH can be used not only as a kind of flavor but also as an important organic intermediate to produce a series of more important flavors and perfumes, such as perillaldehyde, perillartine, etc. We have studied the isomerizatiom of 2,10-epoxypinane and distribution of the products in the past years. It was discovered that liquid phase isomerization of 2,10-epoxypinane produced mainly POH and myrtenol catalyzed by ammonium nitrate in MeNO₂, a kind of strongly polar protonic solvent, and myrentol could be further converted to POH in the presence of NH4NO3. This method was very simple and could be easily performed with a high yield of POH. Basing on these works, we emphasized our study on the design and application of the acid catalysts, and obtained some valuable results.1. A series of nitrate catalysts of nitrogen-containing compounds have been designed and prepared based on the isomerization mechanism of 2,10-epoxypinane and their catalytic performance was investigated. Experimental results indicated that the catalytic activity was correlated closely with the acidity and the dimensional framework of the Bronsted acid site in catalysts. The catalytic activity for selective isomerization of 2,10-epoxypinane to POH followed the order: primary amine nitrate > secondary amine nitrate > tertiary amine nitrate. The active order of different primary amines was as follow: Aniline > Cyclohexylamine > Propylamine > Ethylamine, Methylamine, Ethylene diamine > p-Nitrophenylamine > Urea > 2,4-Dinitrophenylamine. The catalysts of [R¹R²R³NH]NO₃ (R\ R², R³ may be H, alkyl, cycloalkyl, aryl, carbonyl, etc.) possessed suitable acidity present good to excellent activity and selectivity. Also, we found that the more closely the structure of the cation in the catalyst with perillyl alcohol resembled, the better the selectivity and yield of POH would be.2. We used several kinds of ionic liquids as the catalyst, such as ethylamine nitrate and l-butyl-3-methylimidazolium nitrate [BMIm]NO₃. The results showed that the isomerization of 2,10-epoxypinane could be thoroughly catalyzed by ethylamine nitrate with 10-15% molar ratio to the reactant for 2h; [BMIm]NO₃ could be used as catalyst or solvent, and the selectivity was as high...