Study On Preparation, Hydrogenation Of 3-Carene And Bromination-esterification Of Carane

As the largest output natural essential oil, turpentine oil can supply us two main componentsα-pinene andβ-pinene, which always the research focuses for scientists. In recent years, 3-carene was gotten more attention for the introduction of new varieties of pine trees and the expansion on resin utilization. The ternary ring structure in 3-carene is rare for chiral source compounds, which mainly exists in some special turpentine oils, especially in Pinus roxbu Rghii and Pinus sylvestris. To enhance the values of 3-carene in research and utilization, the rectification of the turpentine for isolation and purification of 3-carene,.the hydrogenation of 3-carene for preparation of carane and the suitable conditions were studied in this paper. The bromination of carane and the esterification of the bromide compounds have also been explored. The results would enrich the chemical utilization of 3-carene and establish the theoretical and practical foundation for the fine and high-valuable development of turpentine. The major achievements have been obtained as below:3-Carene was gotten from the rectifying of turpentine that contains about 20 % of the compound. The effects of top temperature of rectifying column, reflux ratio and total reflux time have been studied for the content of 3-carene. It was proved that 3-carene can be separated easily withβ-pinene in the conditions of reflux ratio 1 to 30, total reflux time 2 h and vacuumn 4 kPa to give 3-carene in purity of 98.4 %.Hydrogenation of 3-carene was researched to prepare carane in an autoclave with a stirrer. The effects of Raney Ni and Pd/C were compared, and the single factor experiment was carried out in parameter ranges: reaction time 3~12 h, the dosage of catalyst 4 %~10 % to raw material by mass, the reaction temperature 60~180℃and the hydrogen pressure 3~9 MPa. The results showed that the optimal reaction conditions were 6 % of Raney Ni to 3-carene by mass, 9 MPa, 100℃, and 3 h. The results of confirming experiments repeated in the conditions, showed that the average percent coversion of 3-carene is 99.5 %, the average yield and selectivity of carane are 96.7 % and 92.8 %, respectively. The bromination of carane and esterification of the bromide have been explored. The main ester component was identified to be 4-caranyl acetate through FT-IR, GC-MS and so on. Therefore the structure of bromide of carane was proved to be 4-bromocarane. It needs further study on the bromination of carane and esterification of the bromide of carane.