Solubility of Ascorbic acid 6-palmitate and Geranyl acetate and Esterification of Geranyl acetate in Supercritical Carbon Dioxide

• Main Authors: Jaw-Yi Wei, 魏肇怡
• Other Authors: Zer-Ran Yu
• Format: Others
• Language: zh-TW
• Published: 2003
• Online Access: http://ndltd.ncl.edu.tw/handle/95306988440942573384

碩士 === 國立嘉義大學 === 食品科學系碩士班 === 91 === Abstract The experimental data at phase equilibrium is the base of operating condition and experimental design of supercritical carbon dioxide fluid extraction. The separation principle of solvent and solutes using supercritical fluid extraction depends on density change, which is controlled by the temperature and pressure in the system. Phase equilibrium theory model associated with experimental data will assist to understand the solubility of substance in supercritical fluid and exact operation. Thus, this study is theoretically and experimentally to investigate the solubility of solid or liquid substance in supercritical carbon dioxide. First, three factors (temperature, pressure and ethanol co-solvent) and three levels partially factor of Box-Behnken model were designed to calculate the solubility of solid substances, ascorbic acid and ascorbic acid 6-palmitate, at phase equilibrium in supercritical fluid liquid phase. The optimum extraction and operating condition of ascorbic acid and ascorbic acid 6-palmitate include temperature(40~60℃), pressure(10、20、30MPa) and ethanol co-solvent added (3、6、9%). Those solubility data were further correlated into the following equation: (1) equation of temperature and pressure；(2) equation of carbon dioxide density and temperature. Results showed that the optimum solubilities of ascorbic acid and ascorbic acid 6-palmitate were operated at 40℃, 10MPa and 9% co-solvent added and at 60, 25MPa and 6% co-solvent added, respectively. Co-solvent added increase solubility. Secondly, two factors (temperature and pressure) and three levels were designed to calculate the solubility of liquid substances, geraniol and geranyl acetate, at phase equilibrium in supercritical fluid vapor phase. The optimum extraction and operating condition of geraniol and geranyl acetate include temperature(40~60℃) and pressure(10、20、30MPa). Results showed that the solubility of geraniol increased with increasing pressure and the optimum pressure to extract geranyl acetate was 20 ~ 25MPa. A higher solubility to extract geraniol and geranyl acetate in carbon dioxide was temperature 60℃。 Supercritical fluid application on enzymatic catalysis is a new arrive technology. The advantages of enzymatic esterification in supercritical carbon dioxide system include carbon dioxide was no poison, no solvent or water solution to be separated, supercritical carbon dioxide was low viscosity but high density and the selectivity of this system can be regulated by water content, temperature and pressure. Three factors (temperature, pressure and esterification time) and three levels partially factor of Box-Behnken model were designed to the optimum condition to convert acetic acid and geraniol into geranyl acetate in a supercritical fluid system. The esterification was conditioned at temperature(40~60℃), pressure(10、20、30MPa) and esterification time(30~90 mins). Result showed that the optimum conversion was operated at temperature 55℃, pressure 10 MPa and reaction time 90 mins。 Key words：Ascorbic acid 6-palmitate、Geranyl acetate、Supercritical carbon dioxide、Phase equilibrium、Solubility、Lipase、Esterification。