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摘要
Phase equilibrium data of caffeine, vanillin, o-ethyl vanillin and a natural rosemary extract (containing 73.9% carnosic acid and 14.7% carnosol) in argon have been determined in present work. %26lt;br%26gt;Solubility data were determined at temperatures of 313.15 K, 333.15 K and 363.15 K and in the pressure range from 0.82 MPa up to 50.27 MPa using a static-analytic method and were compared to solubility data of the same substances in CO2. %26lt;br%26gt;Maximal solubility of vanillin in argon was obtained at a temperature of 313.15 K and a pressure of 418 MPa, approx. 0.015 g/g. Comparing the solubility data of pure vanillin in argon and in CO2 higher solubility in argon is observed at lower temperatures and pressures. For o-ethyl vanillin the solubility in argon is higher in comparison to solubility in CO2 in the entire range of pressure, especially at higher temperatures. %26lt;br%26gt;Maximal solubility of caffeine in argon was observed at a temperature of 363.15 K 0.001361 g caffeine/g argon at 38.9 MPa. With increasing pressure solubility increases, while temperature does not have a noticeable impact in the temperature range from 313.15 K to 333.15 K; the solubility increased with increasing temperature to 363.15 K. Similarly, solubility of carnosic acid extract increases with increasing pressure, from about 0.0097 x 10(-2) g substance/g gas at 2.08 MPa and at 313.15 K to 0.0338 x 10(-2) g substance/g gas at 50.27 MPa and at 363.15 K. %26lt;br%26gt;Solubility of the investigated compounds in argon is a function of both, pressure and temperature. Generally, pressure significantly impacts solubility particularly up to a pressure of 20.0 MPa in case of vanillin and up to 30 MPa in case of o-ethyl vanillin and carnosic acid extract. An additional increase of pressure has only a slight impact on solubility. In the case of caffeine, the impact of pressure on the solubility becomes more evident at pressures higher than 20 MPa.
- 出版日期2014-11
