Synthesis And Selective Oxidation Of Optical Perillyl Alcohol

Studies on synthesis and selective oxidation of optical perillyl alcohol are an important procedure to develop abundant turpentine oil of our country and to synthesize a series of fine chemicals. Perillyl alcohol is obtained from rearrangement of 2,10-epoxypinane, which is prepared by epoxidation of 3 -pinene. 3 -pinene is a crucial component of turpentine oil. Perillyl alcohol 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. For example, Perillyl aldehyde can be prepared by selective oxidation of perillyl alcohol, and perillatine, obtained from oxidation of perillyl aldehyde, is a sort of new food additive with properties of high sweetness, low caloricity, good flavor and without toxin etc. Synthesis of perillyl alcohol by rearrangement of beta-pinene epoxide is the simplest method reported by literature from 1970 to 2002. But there are some shortcomings in industry production such as low yield of perillyl alcohol, high degree of polymerization, tedious separation of products and so on. In this thesis, rearrangement reaction of 2,10-epoxypinane and selective oxidation of perillyl alcohol are investigated. Some valuable results are obtained as follows:1. The reaction and the product distribution of liquid isomerization of 2,10-epoxypinane are studied. Effects of reaction conditions on isomerization are investigated. It is discovered that isomerization of 2,10-epoxypinane produce mainly perillyl alcohol in 353 ~ 363 K catalyzed by acid catalysts in strongly polar protonic solvent. Perillyl alcohol can be obtained with 43.8% yield, 98.9% conversion of 2,10-epoxypinane and 39.6% polymerization in optimum condition.2. Effects of reaction conditions on isomerization in fixed bed are also studied. The results show that synthesis of perillyl alcohol in fixedbed is better than in stirred reactor in reducing degree of polymerization, improving yield of perillyl alcohol and simplifying separation of products. Perillyl alcohol can be obtained with 69.9% yield, 91.2% conversion of 2,10-epoxypinane and degree of polymerization is near to 0 in the optimum conditions in 353 K, 1.5/h space velocity and the volume ratio of solvent to 2,10-epoxypinane is 8 to 1.3. Selective oxidation of perillyl alcohol to perillyl aldehyde is studied in the presence of active MnO2, CrO3/SiO2 supported oxidant and Na2Cr2O7. The results show that active MnO2 can be used to oxidize perillyl alcohol to perillyl aldehyde selectively, and conversion of perillyl alcohol is 99.7%, yield of perillyl aldehyde is over 70% in optimum reaction condition with ethyl acetate as solvent, under solvent reflux temperature for 4 h, the mass ratio of oxidant to perillyl alcohol is 4 to 1. CrCVSiO2 supported reagent, prepared by dry mixing method, is an efficient oxidant which oxidize perillyl alcohol to perillyl aldehyde in liquid phase under mild conditions, and conversion of perillyl alcohol is 95.0%, yield of perillyl aldehyde is 57.9% with dichloromethane as solvent under room temperature for 90 min, the ratio of oxidant to perillyl alcohol is 2.5 to 1, loading of CrO3 is 2 mmol/g. The yield of perillyl aldehyde is 40.0% in optimum reaction conditions by 33-orthogonal experiments with the technology of distillation by Na2Cr2O7 oxidant.