Iranian Journal of Chemical Engineering Vol. 7, No. 4 (Autumn), 2010, IAChE Research note Measurement and Correlation of Ibuprofen in Supercritical Carbon Dioxide Using Stryjek and Vera EOS M. Mirzajanzadeh1, F. Zabihi2∗, M. Ardjmand1 1- Islamic Azad University, Tehran South Branch, Faculty of Graduate Studies, Department of Chemical 2- Islamic Azad University, Ayatollah Amoli Branch,Department of Chemical Engineering, Amol-Iran. Abstract Ibuprofensolubility in supercritical carbon dioxide was measured using a dynamic apparatus at a pressure between 80 and 140 bars at three different temperatures, 308.15, 313.15 and 318.15 K. The mole fraction of Ibuprofen in fluid phase was in the range of 0.015 × 10-3 - 3.261 × 10-3 at the mentioned operational condition. Modified Mendez-Santiago and Teja equation were used to check the consistency of the experimental data. Results were correlated using the Stryjek and Vera equation of state with the van der Waals 1-parameter (vdW1) and 2-parameters (vdW2) mixing and combining rules. Interaction parameters along with the percentage of the average absolute relative deviation (%AARD) were displayed. Also, the Lydersen group contribution methods were used for predicting the physicochemical and critical properties of the Ibuprofen. Keywords: Ibuprofen Solubility, Supercritical Carbon Dioxide, Stryjek and Vera EOS, Mendez-Santiago and Teja Equation 1- Introduction
Solubility data are essential for an accurate
promoting high mass transfer, at least an
design of the operational conditions and to
calculate the concentration of supercritical
liquids. In other words, a small change of
solution, in order to investigate the feasibility
of SCF based processes. Supercritical fluids
temperature) gives rise to a large change in a
are useful in a variety of applications as food
supercritical fluid density, in spite of a dense
and pharmaceutical industries. Supercritical
liquid character. Therefore, the solvent
fluids have been established as powerful
properties of a fluid change significantly,
solvents for many non volatile and thermal
supercritical area has gas-like diffusivity,
∗ Corresponding author: [email protected]Measurement and Correlation of Ibuprofen in Supercritical Carbon Dioxide Using Stryjek and Vera EOS
Based on the supercritical fluids 2.2- Solubility measurements characteristics, the solubility of a solid
dynamic technique for the pressure between
To predict the solubility of a solute in
supercritical fluids, EOS models are widely
used. Cubic EOSs are the simplest equations
capable of predicting and representing fluid phase equilibrium. Mixing rules are necessary when equations of state are applied to calculate the fluid mixtures thermodynamic properties. Although cubic EOS’s are the simplest mathematical models, capable of predicting fluid phase equilibrium, semi-empirical models are often utilized because of their relative ease of application
Figure 1. Schematic diagram of the experimental
commonly based on providing a correlation
apparatus:1) gas tank, 2 ) ball valve, 3,11) pressure
gauge indicator, 4,8,12,14,15,18) needle valve, 5)
Current investigation has been organized to
pump, 6) filter 7) pre-heater, 9,10) equilibrium-sell 16) throttling valve , 17) constant temperature bath
supercritical CO2 in low pressure range (80-140 bars). Results have been drawn as three
isotherms ( in 308.15, 313.15 and 318.15K).
through a 0.5μm filter, to reach the desired
Stryjek and Vera equation of state was used
pressure. The compressed fluid entered into
to correlate the experimental data within the
a preheating coil contained in a temperature-
controlled electronic oven to achieve thermal
equilibrium and passed into a solubility cell
that was packed with pure Ibuprofen powder.
The solute laden purged to the atmosphere in
order to ensure the operational condition
consistency. The sampling part was a ”, 2- Experimental method 2.1- Materials
Ibuprofen (Sina Daru, 99.99% purity) was
unilateral needle valves. This pass was kept
(Roham Gaz, 99.95%) was also used as the
minutes the purge valve was closed and the
solvent. Ethanol (99.8%, Sigma Aldrich) was
needle valves were opened orderly. A sample
of supercritical solution was trapped into the
Iranian Journal of Chemical Engineering, Vol.7, No. 4
sampling pass by closing the needle valves.
The sampling equipment (coil and valves)
affected by the supercritical solvent pressure
marinated in the pure ethanol. The valves
out and all the solute was washed out by
solvent power to increase. In addition, the
ethanol. The ethanol-Ibuprofen solution was
prepared for GC test to determine the solute
Table 1. Experimental molar fraction solubility of T(K) P(MPa) y ×
operational pressure and temperature in all
performed in triplicate in each operational
3- Results and discussion 3.1- Experimental results
shown in Fig. 2 and are supported by data in
Figure 2. Experimental solubility data obtained in 308.15, 313.15 and 318.15 K and the pressure range
According to the experimental results, the
mole fraction of ibuprofen in the fluid phase
was in the range from 0.015 × 10-3 - 3.261 ×
Iranian Journal of Chemical Engineering, Vol. 7, No. 4 Measurement and Correlation of Ibuprofen in Supercritical Carbon Dioxide Using Stryjek and Vera EOS
more effective factor. Because although the
solubility power in a constant pressure,
changes with the temperature increasingly in
temperature, the E factor impression by the
in the higher pressure ranges. This result can
be interpreted by the iso-fugacity criteria
3.2- Correlation of solubility using Stryjek and
If the solid phase does not dissolve the SC-
2, solute solubility in the CO2-riched fluid
phase at equilibrium can be calculated using
⎛ v (P − P ) ⎞
the equation (1). The Stryjek and Vera EOS
has been selected to calculate SCF
At a constant pressure, both the E and sub
value affect the solubility. At pressures
higher than the crossover point (about 120
mixing rules may be used to calculate the
bar), the effect of E is relative to the solid
mixture parameter 'a' and 'b' in SV-EOS.
component sublimation pressure intensively.
In low pressure ranges, molecular with the mixing and combining rules and the interactions between Ibuprofen and carbon
dioxide become severely weak by increasing
the temperature. On the other hand, in higher pressure ranges, sublimation pressure is the
Table 2. Summary of the cubic EOS, mixing and combining rules and fugacity coefficient v(v + b) + b(v − b)
⎡ 2a y + 2 a a 1(− k 1
− a (b − l (b + b 1
Iranian Journal of Chemical Engineering, Vol.7, No. 4
The Correlation is performed by minimizing
the objective function of Average Absolute
also used to predict the physicochemical and
critical properties of the Ibuprofen that are
interaction parameters (k12 and l12) showed
the best fitting between the experimental data
and the calculated values (by SV-EOS and
van der Waals mixing rules) (Table 4). A
A trial and error algorithm was provided and
comparison between the correlation results
optimized values computation. The loop was
different mixing rules is illustrated in Fig. 3.
Table 3. Physicochemical and critical properties of the ibuprofen and CO2
Ibuprofen 749.7a 2.33a 0.819a 182.1b 4.95c 8.97c 16.0c
b Estimated by Immirzi and Perini method
Table 4. Optimized interaction parameter for the modeling of Ibuprofen solubility in CO2
with the SV-EOS and the van der Waals mixing rules
Parameter Iranian Journal of Chemical Engineering, Vol. 7, No. 4 Measurement and Correlation of Ibuprofen in Supercritical Carbon Dioxide Using Stryjek and Vera EOS Table 5. Modified Mendez-Santiago-Teja modeling results Figure 3. Experimental solubility of Ibuprofen in SC- CO2 at 308.15(+), 313.15(o) and 318.15K(∗) and correlation results obtained with SV EOS using the vdW1 and vdW2 Figure 4. Experimental solubility data for Ibuprofen and values correlated by modified M-S-T model 3.3- Modeling with a density-based correlation 4- Conclusions
Ibuprofen in SC carbon dioxide as a function
mathematical models using Stryjek and Vera
of absolute temperature and solvent density,
we used the semi-empirical Mendez-Santiago
supercritical carbon dioxide. Solubility
values were measured in a 308.15, 313.15
and 318.15K and 80-120 pressure range. The
experimental data correlate well with the SV
EOS model with an average absolute relative
T ln yP = A + Bρ + CT
deviation (AARD%) of 10–23% along with
the vdW1 mixing rule and 6-14% along with
values are presented in Table 5 in the three
results than vdW1, which is probably due to
The experimental results were plotted in the
the two available adjustable parameters,
form of T ln y P − CT against the supercritical
which can offer a higher flexibility to the
CO2 density, to test the M-S-T model self-
consistency (Fig. 4). The linear behavior
solubility data. These data are also well
shown in Fig. 4 confirms that the measured
correlated by the semi-empirical model of
solid solubility data are consistent at all
modified Mendez–Santiago–Teja with an
AARD% of 9–11%. The correlated parameters in the semi-empirical models are
Iranian Journal of Chemical Engineering, Vol.7, No. 4 5- Nomenelature
expansion of supercritical solution", J. Powder Technology, 154, 83-94, (2005). A , B and C adjustable parameters
[5] Dashtizadeh, A., Pazuki, G.R., Taghikhani, V.
and Ghotbi, C., "A new two-parameter cubic
eq. of state for predicting phase behavior of
pure compounds anf mixtures", J. of Fluid Phase Equilib., 242, 19, (2006).
[6] Madras, G. "Thermodynamic modeling of the
solubilities of fatty acids in supercritical
fluids", J. of Fluid Phase Equilibria, 220, 167, (2004).
[7] Zabihi, F., Akbarnejad, M.M., Vaziri, A.,
Arjomand, M. and Seyfkordi, A. A., "Drug
nano-particles formation by supercritical
condition effects investigation", IJCCE, 28,
[8] Chrastil, F. J. "Solubility of solids and liquids
in supercritical gases", Phys. Chem86,
[9] Fages, J., Lochard, H., Letourneau, J. J.,
Sauceau, M. and Rodier, E. "Particle
generation for pharmaceutical applications
References
using supercritical fluid technology",
[1] Fages, J., Luchard, H., Letorneau, J.J. and
Powder Technol.141, 219, (2004).
Sauceau M., "Particle generation for
[10] Su, C. S., Chen, Y. P. "Measurement and
correlation for the solubility of nonsterodial
supercritical fluid technology", Powder Technol, 141, 219 (2004).
supercritical carbon dioxide", J. Supercrit.
[2] Yildiz, N., Tuna, S., Duker, O. and Calimli,
Fluids43, 438, (2007).
A., "Particle size design of digitoxin in
[11] Güçlü-Üstünda˘g, Ö. and Temelli, F.
supercritical fluids", J. of Supercritical
"Correlating the solubility behavior of fatty
Fluids, 41, 440 (2007).
acids, mono, di, and triglycerides, and fatty
[3] Chen, Y. and Koberstein J.T., "Fabrication of
acid esters in supercritical carbon dioxide",
block copolymer monolayers by adsorption
Ind. Eng. Chem. Res. 39, 4756, (2000).
from supercritical fluids: A versatile concept
[12] Soares, B.M.C., Gamarra, F.M.C., Paviani,
for modification and functionalization of
L.C., Gonc, Alves, L.A.G. and Cabral, F.A.
polymer surfaces", Langmuir, 24, 10488-
"Solubility of triacylglycerols in super-
critical carbon dioxide", J. of Supercritical
[4] Hirunsit, P., Huang, Z., Srinophakon, T.,
Fluids43, 25, (2007). Iranian Journal of Chemical Engineering, Vol. 7, No. 4 Measurement and Correlation of Ibuprofen in Supercritical Carbon Dioxide Using Stryjek and Vera EOS
[13] Sparks, D. L., Hernandez, R. and Antonio
[16] Charoenchaitrakool, M., Dehghani, F. and
Estevez, L. "Evaluation of density-based
Foster, N.R., "Micronization by rapid
supercritical carbon dioxide and formulation
of a new model", J. of Chemical
water-soluble pharmaceuticals", J. of Ind. Engineering Science, 63, 4292 (2008). Eng. Chem. Res., 39(8), 4794 (2000).
[14] Coimbra, P., Duarte, C.M.M. and Susa,
[17] Sparks, D. L., Hernandez, R. and Estevez,
H.C.de, "Cubic equation-of-state correlation
A., "Evaluation of density-based models for
of the solubility of some anti-inflammatory
the solubility of solids in supercritical
drugs in supercritical carbon dioxide", J. of Fluid Phase Equilibria, 239(5), 188 (2006).
model", J. of Chemical Engineering Science,
[15] Housaindokht, M.R. and Bozorgmehr, M.R.,
63(9), 4249 (2008).
"Calculation of solubility of methimazol, phenazopyridine and propanol in supercritical carbon dioxide", J. of Supercritical Fluids, 43(2), 390 (2008). Iranian Journal of Chemical Engineering, Vol.7, No. 4
Is it safe for pregnant women to use NRT? Lifestyle (avoiding people, places and things that trigger smoking) and behaviour changes (delaying and distractingtechniques) are recommended first before considering NRT. If you are unable to quit, try NRT aer the first trimester(3 months). If you are pregnant or breastfeeding, always check with your doctor before using any medications; thisinclu
(c.c. 19 novembre 2002), Pres. Zumbo - Est. Grillo - P.M. Ciampoli (conf.) - Ric. Marton. In tema di tutela dei brevetti per specialità medicinali, la c.d. “eccezione galenica “ prevista dall’art. 1 del R.D. 29 giugno 1939 n. 1127 (nel testo sostituito dall’art. 1 del D.P.R. 22 giugno 1979 n. 338), secondo cui “ la facoltà esclusiva attribuita dal diritto di brevetto non si este