Solubility of a spiroindolinonaphthoxazine photochromic dye in supercritical carbon dioxide: Experimental determination and correlation

The measurement and correlation of the experimental solubility of a spiroindolinonaphthoxazine photochromic dye (1,3-dihydro-3,3-dimethyl-1-isopropyl-6′-(2,3)-(dihydroindole-1-yl)spiro[2H-indole-2,3′-3H-naphtho[2,1-b] [1,4] oxazine]) in supercritical carbon dioxide (scCO₂) is reported. Results were obtained using a static analytical method, at 308.0, 318.0 and 328.0 K, and in a pressure range from 10.0 to 26.0 MPa. Solubility experimental data were correlated with three density-based models (Chrastil, Bartle and Méndez-Santiago–Teja models), with the Ziger–Eckert semi-empirical correlation and with two cubic equation-of-state (EOS) models, namely the Peng–Robinson EOS (PR-EOS) and the Soave–Redlich–Kwong EOS (SRK-EOS), together with the conventional van der Waals mixing and combining rules. Good correlation results were obtained between the calculated and experimental solubility, to all fitted models. Solubility results clearly indicate the feasibility of processing this dye, and possibly this class of photochromic dyes, using supercritical fluid technologies and processes, for example, supercritical fluid dye impregnation of polymer host materials.     

Measurement and correlation of solubility of artemisinin in supercritical carbon dioxide

Artemisinin is an effective antimalarial drug isolated from the herbal medicine Artemisia annua L. Supercritical fluid extraction is an environment-friendly method for the extraction of artemisinin. In this work, the solubility of artemisinin in supercritical carbon dioxide was determined by static method at three temperatures of 313 K, 323 K, 333 K and pressures from 11 to 31 MPa. The range of experimental solubility data was from 0.498 × 10⁻³ to 2.915 × 10⁻³ mol/mol under the above-mentioned conditions. Two density-based models (Chrastil and Mendez–Santiago–Teja models) were selected to correlate the experimental data of this work, and the average absolute relative deviation (AARD) was 8.32% and 8.33%, respectively. The correlation results showed good agreement with the experimental data.     

Solubility of iodopropynyl butylcarbamate in supercritical carbon dioxide

Supercritical carbon dioxide has been considered an appropriate alternative for extraction and purification process of cosmetics, pharmaceuticals, food supplements and natural products. Solubility information of biological compounds is essential for choosing supercritical fluid (SCF) processes. The solubility of iodopropynyl butylcarbamate (IPBC), a fungicide and anti-dandruff agent, was measured in supercritical carbon dioxide with a high pressure apparatus equipped with a variable volume view cell at 313.15, 323.15, and 333.15 K and at pressure between 80 and 35 MPa. The experimental data were correlated well with Peng–Robinson equation of state (PR EOS) and quasi-chemical nonrandom lattice fluid model.     

Solubility of dihydroxybenzene isomers in supercritical carbon dioxide

The equilibrium solubilities of dihydroxybenzene isomers pyrocatechol, resorcinol and hydroquinone have been measured in supercritical carbon dioxide using a simple static method. The measurements were performed in the pressure range from 120 to 400 atm at temperatures 35, 45, 55 and 65°C for pyrocatechol and resorcinol and in the pressure range from 120 to 200 atm at temperature 35°C for hydroquinone. The solubility of the isomers in supercritical CO₂ was found to vary in the order pyrocatechol>resorcinol≫hydroquinone. The experimental data were correlated by use of the density based model proposed by Chrastil.     

Solubility and micronisation of phenacetin in supercritical carbon dioxide

The rapid expansion of a supercritical solution (RESS) process represents an attractive prospect for producing sub-micron and nano-particles of medical compounds with low solubility. The solubility of phenacetin in supercritical carbon dioxide was measured by the analytical-isothermal method at pressures ranging from 9.0 MPa to 30.0 MPa and temperatures ranging from 308.0 K to 328.0 K. The results show that the mole fraction solubility of phenacetin in supercritical carbon dioxide is up to 10^?5. Four density-based semi-empirical models were introduced to correlate the experimental data. Agreement between the model predictions and experimental data is greater with the Adachi-Lu-modified Chrastil model than with the Chrastil model, Méndez-Santiago-Teja model, and the Bartle model and the average absolute relative deviation (AARD) observed is 0.0483. The preparation of fine phenacetin particles by the RESS process under different conditions of extraction temperatures (308.0–328.0 K), extraction pressures (9.0–30.0 MPa), nozzle temperatures (373.0–393.0 K), nozzle diameters (0.1–0.8 mm), and collection distance (20.0–40.0 mm) was investigated. The size and morphology of the resultant particles were analysed by SEM. A remarkable modification in size and morphology can be obtained by condition-optimisation.     

Measurement and correlation of solubility of anthraquinone dyestuffs in supercritical carbon dioxide

Solubility data of 1,4-diaminoanthraquinone (C.I. Disperse Violet 1) and 1,4-bis(ethylamino)anthraquinone (C.I. Solvent Blue 59) in supercritical carbon dioxide (sc-CO₂) have been measured at the temperatures of (323.15, 353.15, and 383.15) K and over the pressure range from (12.5 to 25.0) MPa by a flow-type apparatus. The solubility of two anthraquinone dyestuffs was obtained over the mole fraction ranges of (1.3 to 26.1) · 10⁻⁷ for 1,4-diaminoanthraquinone (C.I. Disperse Violet 1) and (1.1 to 148.5) · 10⁻⁷ for 1,4-bis(ethylamino)anthraquinone (C.I. Solvent Blue 59). The experimental results have been correlated with the empirical equations of Mendez-Santiago–Teja and Kumar–Johnston expressed in terms of the density of sc-CO₂, and also analyzed thermodynamically by the regular solution model with the Flory–Huggins theory and the Peng–Robinson equation of state modified by Stryjek and Vera (PRSV-EOS) with the conventional mixing rules. Good agreement between the experimental and calculated solubilities of the dyestuffs was obtained.     

Solubility of trifluoroethoxyphthalocyanines and -subphthalocyanines in liquid and supercritical carbon dioxide

In an analysis of the solubility of a wide range of phthalocyanines (Pcs) and its analogues (SubPcs) in liquid and/or supercritical CO₂, compounds with trifluoroethoxy substituents were found to exhibit high solubility. To our knowledge, this is the first example of Pc compounds soluble in 100% CO₂. This unprecedented unique property of trifluoroethoxy substituted Pcs might have particular applications in catalysis in organic reactions as well as dyes for solar cells by CO₂ delivering coatings.     

Measurement and correlation of solubility of benzamide in supercritical carbon dioxide with and without cosolvent

The experimental equilibrium solubility of benzamide in supercritical carbon dioxide was measured at temperatures between 308 K and 328 K and for pressures from 11.0 MPa to 21.0 MPa using a dynamic flow method. The effects of three cosolvents - ethanol, acetone and ethylene glycol, were investigated at a cosolvent molar concentration of 3.5%. The results showed that the solubility was enhanced by the presence of the three cosolvents, and ethanol exhibited the highest cosolvent effect. The solubility data in the absence and presence of cosolvents were correlated by two density-based models. The calculated results showed satisfactory agreement with the experimental data.     

Solubility of chelating agents and metal-containing compounds in supercritical fluid carbon dioxide

The solubility of 49 metal-containing compounds and 15 "free" ligands in supercritical fluid carbon dioxide is reviewed. Solubilities were found to range over eight orders of magnitude, with the highest value of solubility being 56 g l(-1). Metals complexed with fluorine substituted ligands were found to be the most soluble, and metals complexed with phenyl-substituted ligands the least soluble. A general trend for increasing solubility with increasing oxidation state is observed and this is correlated with the increased number of coordinating ligands protecting the metal center from interaction with the supercritical fluid and also due to the increased number of solvation interactions with the increased number of ligand groups.     

Solubility in supercritical carbon dioxide: importance of the Poynting correction and entrainer effects

Gibbs ensemble Monte Carlo simulations were used to investigate the effect of pressure and of entrainers on the solubility of low-volatility species in CO 2. Two entrainers were examined, n-octane and methanol, as well as two solutes, hexamethylbenzene and benzoic acid. For the three pressures studied (12, 20, and 28 MPa), the simulations demonstrate that the increase in the solubility with increasing pressure is mostly due to an increase in the solute's chemical potential (as expressed by the Poynting correction) and not due to an increase in the solvent strength of supercritical CO 2. The presence of an entrainer enhances solubility, particularly when the solute and entrainer can form hydrogen bonds. The solubility of benzoic acid is enhanced by an order of magnitude upon addition of methanol entrainer, whereas the enhancements are less than 2 for the other systems.     

Solubility of novel open-chain crown ether bridged diphosphates in supercritical carbon dioxide

The solubility of newly synthesized chelating agents, i.e., tetraethylene glycol bis (2-ethylhexyl) dimethyl diphosphate (EG4EH), tetraethylene glycol bis (n-octyl) dimethyl diphosphate (EG4Oct), and tetraethylene glycol bis (2-butoxyethyl) dimethyl diphosphate (EG4BOE) in supercritical carbon dioxide (scCO₂) were determined at temperatures ranging from (318.15 to 333.15) K and pressures ranging from (12 to 21) MPa. Solubility increases in the order of EG4Oct (MW = 606.33) < EG4BOE (MW = 582.26) < EG4EH (MW = 606.33), indicating that branched side chains of the ligands play an important part in increasing solubility in scCO₂. Semi empirical density-based models proposed by Bartle and Chrastil were used to correlate the experimental data, and AARD values were calculated to be (1.2 to 2.9)% and (0.40 to 0.93)% for Bartle and Chrastil model, respectively. Additionally, the partial molar volumes of those compounds were estimated following the theory developed by Kumar and Johnston.     

Solubility of chlorobutane,ethyl methacrylate and trifluoroethyl acrylate in supercritical carbon dioxide

In this work, the solubility of chlorobutane, ethyl methacrylate and trifluoroethyl acrylate in supercritical carbon dioxide (SC CO₂) was determined. The solubility of hexane, styrene and chlorobenzene was also measured for comparison. The effect of the polar substitute on the solubility of different kind of compound in SC CO₂ was discussed. The dependence of the solubility of the solute on the density of the binary system was also investigated and a proximate linear relationship existed between this solubility and density.     

Solubility of disperse yellow 54 in supercritical carbon dioxide with or without cosolvent

Extraction of disperse yellow 54 with supercritical carbon dioxide was conducted at 393.2 K and 30 MPa over a wide range of contact times. Saturated solubilities of the disperse dyestuff in supercritical carbon dioxide with or without cosolvent were also measured over the temperature and pressure ranges of 353.2 K to 393.2 K and 15 MPa to 30 MPa. Either ethanol or dimethyl sulfoxide, up to 5 mol%, was used as a cosolvent. As evidenced from the experimental results, the magnitudes of equilibrium solubility can be effectively enhanced in the presence of both two cosolvents. Dimethyl sulfoxide was found to yield higher solubility enhancement. Cosolvent effects were discussed on the basis of the Kamlet-Taft solvatochromic solvent parameters of cosolvents. The saturated solubility data were correlated with the Chrastil and the Mendez-Santiago and Teja equations. The Chrastil model correlated the solubility data to about within the experimental uncertainty. The correlated results of the Mendez-Santiago–Teja model supported the consistency of the solubility data over the entire experimental conditions.     

Solubility of carbon dioxide in aqueous solutions of sodium chloride: Experimental results and correlation

The solubility of carbon dioxide in aqueous solutions of sodium chloride was measured in the temperature range from 40 to 160°C, up to 6 mol-kg salt solutions and total pressures up to 10 MPa. Pitzer's⁽¹⁾ equations as well as the Chen and Evans⁽²⁾ model were used to correlate the new data. Results are reported and compared to literature data and correlations.     

在超临界CO2流体中的化学反应

超临界CO2流体中的化学反应是继超临界流体应用于萃取分离过程之后进一步将其应用于化学反应的新尝试。本文重点综述了超临界CO2流体中的化学反应研究进展, 并对其发展前景作了展望。     

Direct deposition of chitosan macromolecules on a substrate from solutions in supercritical carbon dioxide: Solubility and conformational analysis

Chitosan and its derivatives are promising materials for coating medical devices because this procedure improves their bio- and haemocompatibility. It is known that supercritical carbon dioxide attracts significant scientific interest in biomedical applications as well. Coatings deposited directly from solutions in supercritical carbon dioxide are expected to have particularly smooth and uniform morphology that should enhance their stability. We have tested the possibility of obtaining chitosan films using direct deposition from solutions in this fluid. In order to reveal benefits of this approach we modelled and studied the initial stage of formation of chitosan coatings with prototype system of depositing pioneer single polymer chains directly from such solutions on a model ultrasmooth mica substrate. We estimated achievable solubility of the chitosan materials in supercritical carbon dioxide and performed conformational analysis of the deposited chitosan chains on a substrate. AFM imaging directly demonstrated that the pioneer macromolecules adsorb as rather extended 2D coils from such solutions.     

Solubility of carbon dioxide in pentaerythritol tetraoctanoate

In this paper, solubility measurements of CO₂ in pure pentaerythritol tetraoctanoate (PEC8) between 273 and 343 K are presented. The experiments were performed according to the static, synthetic method. The data are represented using the Peng–Robinson equation of state with the Huron–Vidal mixing rules and the UNIQUAC equation for the excess Gibbs Energy (g^E) at infinite pressure. This system shows immiscibility in liquid phase, with lower critical end point (LCEP) at T = 268 ± 0.1 K and xCO₂=0.98±0.001$x_{\text{C}{\text{O}}_2}=0.98\pm 0.001$ and upper critical end point (UCEP) at the critical point of pure CO₂.     

Dissolution of uranium dioxide in supercritical fluid carbon dioxide

Uranium dioxide can be dissolved in supercritical CO2 with a CO2-philic TBP-HNO3 complexant to form a highly soluble UO2(NO3)(2).2TBP complex; this new method of dissolving UO2 that requires no water or organic solvent may have important applications for reprocessing of spent nuclear fuels and for treatment of nuclear wastes.     

Monoacetylferrocene crystallization in supercritical carbon dioxide

An organometallic compound, monoacetylferrocene, was for the first time obtained as single crystals by crystallization from supercritical carbon dioxide. This offers the possibility of utilizing supercritical media for efficient crystallization and purification of organometallic compounds without using organic solvents. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 555–557, March, 2006.