Solubility behavior of pure components (camphene and caryophyllene oxide) at subcritical and supercritical conditions of carbon dioxide
Subcritical and supercritical fluids are good solvents because they possess liquid-like density and gas-like diffusivity and viscosity, which allow quick equilibration and micro pore permeation of fluid. Advantages of using subcritical and supercritical fluid are environmental friendly, less cont...
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| Main Author: | |
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| Format: | Thesis |
| Language: | English |
| Published: |
2014
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| Subjects: | |
| Online Access: | http://psasir.upm.edu.my/id/eprint/91446/1/FSTM%202014%202%20-%20IR.pdf |
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| Summary: | Subcritical and supercritical fluids are good solvents because they possess liquid-like
density and gas-like diffusivity and viscosity, which allow quick equilibration and
micro pore permeation of fluid. Advantages of using subcritical and supercritical
fluid are environmental friendly, less contamination of final product, energy saving
and easy to control. In order to develop subcritical and supercritical processes,
fundamental knowledge about thermophysical properties and phase equilibrium
knowledge are crucial. With solubility data of compounds in subcritical and
supercritical condition of solvent, these processes can be designed, scaled up and
optimized. One major problem currently is that this fundamental knowledge is still
lacking or limited to specific thermodynamic range. With all these problems, this
study is significant with objectives to design and develop an experimental rig for
solubility study, to investigate the effect of temperature and pressure on solubility
behavior and to identify suitable mathematical model that correlates solubility data
with changes of thermodynamic condition. In this study, solubility behavior of two
active compounds from Malaysia local herbs, which are camphene and
caryophyllene oxide, were investigated because of their medicinal values and
unavailability of their solubility data. Experimental apparatus was developed based
on dynamic method that coupled with off-line gravimetrically analysis for its
convenience and better accuracy. As the apparatus had been assembled, it was
subjected to validation with naphthalene to determine suitable flow rate for the
experiment (4 ml/min) and to check the workability and accuracy of apparatus. Then,
solubility study was carried out for camphene and caryophyllene oxide under
subcritical (298. 15K and 303.] 5 K, 50 - 70 bar) and supercritical conditions (308. I5
K and 3 I 3.] 5 K for camphene, 308. 15K and 3 I 8. 15K for caryophyllene oxide; 80 _
250 bar) of carbon dioxide. Solubility behavior of both compounds under subcritical
carbon dioxide condition increased significantly with minor increment in pressure
and temperature because density of solvent is very sensitive in subcritical region. In
supercritical condition, retrogradation behavior happened and therefore solubility of both compounds decreased when temperature increased. However, solubility of both
cornpound-; still increased with pressure. Three commonly used semi-empirical
models. Which are Bartle model. Chrastil model. and Mendez-Santingo-Teja model,
were tested to correlate solubility data with density of carbon dioxide. Of these three
models, Mendez-Santiago-Teja model showed excellent fitting for both compounds
in subcritical and supcrcritical condition with average absolute relative deviataion kept below 21% |
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