Measurements of Binary Diffusion Coefficients in Supercritical Carbon Dioxide
Chang Yi Kong*
Graduate School of Engineering and Research Institute of Green Science and Technology, Shizuoka University, 3-5-1 Johoku, Naka-ku, Hamamatsu, 4328561, Japan
- *Corresponding Author:
- Chang Yi Kong
Graduate School of Engineering and
Research Institute of Green Science and Technology
Shizuoka University, 3-5-1 Johoku
Naka-ku Hamamatsu 432-8561 Japan
Received date: November 25, 2014; Accepted date: November 25, 2014; Published date: November 26, 2014
Citation: Kong CY (2014) Measurements of Binary Diffusion Coefficients in Supercritical Carbon Dioxide. J Chromatograph Separat Techniq 5:e127. doi:10.4172/2157-7064.1000e127
Copyright: © 2014 Kong CY. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
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A supercritical fluid (SCF) is an adjustable solvent which is reached at a temperature and pressure higher than its critical point. It can diffuse through solids like a gas, and dissolve materials like a liquid. In addition, close to the critical point, small changes in pressure or temperature result in large changes in density or viscosity, allowing many properties to be tuned. SCFs are suitable as a substitute for organic solvents in a range of industrial processes. Furthermore, there is no surface tension in a SCF, as above the critical temperature there is no phase transition. The applications of SCF is still expanding in the fields of extraction [1,2] food  pharmaceutical [4,5] material [6-8] and chemical reaction . The quantitative knowledge of mass transport phenomena such as diffusion coefficients of various compounds in SCF is of considerable important in the design and efficient operation of the newly proposed SCF processes. Experimental methods, compounds and SCFs employed to determine the diffusion coefficients are highlighted in this editorial.
Diffusion is caused by random molecular motion that leads to complete mixing. In chromatography, the diffusion coefficient refers to the diffusion of a solute in a relatively or very dilute solution. So far, a number of experimental methods such as solid dissolution (SD) [10,11] pseudo steady-state solid dissolution (PSTD)  photon correlation spectroscopy (PCS)  radioactive tracer response (RTR) [14,15] nuclear magnetic resonance (NMR) [16,17] Taylor-Aris dispersion [18,19] modified Taylor- Aris dispersion [20,21] and chromatographic impulse response (CIR) [22,23] have been developed for measuring binary diffusion coefficients in SCFs. Among the above methods, most literature data [24-26] on binary diffusion coefficients in SCFs have been made by the Taylor-Aris dispersion and the CIR methods. The latter involves chromatographic adsorption, and the former does not.
Supercritical (SC) CO2 is known to be the most stable and an excellent solvent and is normally used in mobile phases for supercritical fluid chromatography (SFC) as well as the applications of SCF over a wide range of fields. The Taylor-Aris dispersion method is adequate for measuring binary diffusion coefficients for lower molecular weight (MW), non and weakly polar compounds in SC CO2. So far, most of compounds used to measure the binary diffusion coefficients by the Taylor-Aris dispersion method in SC CO2 have lower MW than 300 and have non or weak polarity.
On the other hand, the modified Taylor-Aris dispersion and the CIR methods can be used to measure polar compounds or higher MW compounds higher than 400 in SC CO2. In fact, Dahmen et al.  measured the binary diffusion coefficients of Squalene (MW=410.7) in SC CO2 by the modified Taylor-Aris dispersion method and Funazukuri et al.  also reported those of α-tocopherol (MW=430.7), β-carotene (MW=536.9) and ubiquinone CoQ10 (MW=863.3) in SC CO2 using by the same method. The CIR method has been employed to measure the binary diffusion coefficients of polar compounds  such as benzoic acid, ethanol, methanol, 1-propanol and 2-propanol, and of metal complexes [28-30] such as ferrocene, 1,1’-dimethylferrocene, palladium(II) acetylacetonate, cobalt(III) acetylacetonate and platinum(II) acetylacetonate in SC CO2. Recently, the binary diffusion coefficients for a number of compounds [31-35] with higher MW such as β-carotene (MW=536.9), dibenzo-24-crown-8 (MW=448.5), diolein (MW=622.0), α-tocopherol (MW=430.7), triarachidonin (MW=951.5), trierucin (MW=1053.8), triolein (MW=885.4), ubiquinone CoQ10 (MW=863.3) and vitamin K1 (MW=452.7) has been measured by the CIR method in SC CO2. Kong group  have first measured the binary diffusion coefficients for the highest MW compound of trinervonin with MW of 1137.9 so far. The CIR method is superior to the Taylor dispersion method in diffusion measurements in SC CO2, especially in the vicinity of the critical point, and for polar or high MW compunds. Although many studies have been paid to the measurements of diffusion coefficients in SC CO2, there are still few works on the diffusion coefficients for polar compounds, drug compounds, metal complexes, and in the region near to critical point, at higher temperature (>100°C) and higher pressure (>40 MPa) region in SC CO2. In addition, the solvents such as 2,3-dimethylbutane,  chlorotrifluoromethane,  ethane, [38-40] ethanol,  hexane, [40,42] propane, [40-43] 2-propanol  and water  are also used as SCFs, in which the binary diffusion coefficients have been measured for various organic compounds with lower MW such as 1,3,5-trimethylbenzene, 1-octene, 1-tetradecene, acetone, benzene, m-cresol, naphthalene, n-decane, n-tetradecane, phenanthrene, phenol, p-xylene, toluene.
- De Melo MMR, Silvestre AJD, Silva CM (2014) Supercritical Fluid Extraction of Vegetable Mmatrices: Applications,Trends and Future Perspectives of A Convincing Green Technology. J Supercritical Fluids 92: 115-176
- Sharif KM, Rahman MM, Azmir J, Mohammed A, Jahurul MHA, Sahena F, Zaidul ISM (2014) Experimental Design of Supercritical Fluid Extraction - A Review. J Food Engineering 124: 105-116.
- King JW (2014) Modern supercritical fluid technology for food applications. Annu Rev Food SciTechnol 5: 215-238.
- Sun Y (2014) Supercritical fluid particle design for poorly water-soluble drugs (review). Curr Pharm Des 20: 349-368.
- Girotra P, Singh SK, Nagpal K (2013) Supercritical fluid technology: a promising approach in pharmaceutical research. Pharm DevTechnol 18: 22-38.
- Truong QD, Devaraju MK, Ganbe Y, Tomai T, Honma I (2014) Controlling the shape of LiCoPOâ‚„ nanocrystals by supercritical fluid process for enhanced energy storage properties. Sci Rep 4: 3975.
- Zeng D, Li R, Yan T, Fang T (2014) Perspectives and Advances of Microalgal Biodiesel Production with Supercritical Fluid Technology. RSC Adv 4: 39771-39781.
- Hoang D, Bensaid S, Saracco G (2013) Supercritical Fluid Technology in Biodiesel Production. Green Processing and Synthesis 2: 407-425.
- Subramaniam B, Chaudhari RV, Chaudhari AS, Akien GR, Xie Z (2014) Supercritical Fuids and Gas-Expanded Liquids as Tunable Media for Multiphase Catalytic Reactions. ChemEngSci 115: 3–18.
- Iomtev MB, sekhanskaya YV (1964) Diffusion of Naphthalene in Compressed Ethylene and Carbon Dioxide. Russ J PhysChem 38: 485-487.
- Tsekhanskaya YV (1971) Diffusion of Naphthalene in Carbon Dioxide near the Liquid-Gas Critical Point. Russ J PhysChem 45: 744.
- Knaff G, Schlüder EU (1987) Diffusion Coefficients of Naphthalene and Caffeine in Supercritical Carbon Dioxde. ChemEngProc 21: 101-105.
- Saad H, Gulari E (1984) Diffusion of Liquid Hydrocarbons in Supercritical CO2 by Photon Corraltion Spectroscopy. BerBunsengesPhysChem 88: 834-837.
- Robb WL, Drickamer HG (1951) Diffusion in CO2 up to 150-Atmospheres Pressure. J ChemPhys 19: 1504-1508.
- Takahashi S, Hongo M (1982) Diffusion Coefficients of Gases at High Pressures in the CO2-C2H4 System. J ChemEng Japan 15: 57-59.
- Lamb DM, Barbara TM, Jonas J (1986) NMR Study of Solid Naphthalene Solubilities in Supercritical Carbon Dioxide near the Upper Critical End Point. J PhysChem 90: 4210-4215.
- Lamb DM, Adamy ST, Woo KW, Jonas J (1989) Transport and Relaxation of Naphthalene in Supercritical Fluids. J PhysChem 93: 5002-5005.
- Taylor G (1953) Dispersion of Soluble Matter in Solvent Flowing Slowly Through A Tube. Proc R Soc London A219: 186-203.
- Aris R (1956) On the Dispersion of A Solute in A Fluid Flowing Through A Tube. Proc R Soc London A235: 67-77.
- Funazukuri T, Kong CY, Kagei S (2002) Measurements of Binary Diffusion Coefficients for Some Low Volatile Compounds in Supercritical Carbon Dioxide by Input-Output Response Technique with Two Diffusion Columns Connected in Series. Fluid Phase Equilib 194-197: 1169-1178.
- Dahmen N, Kordikowski A, Schneider GM (1990) Determination of Binary Diffusion Coefficients of Organic Compounds in Supercritical Carbon Dioxide by Supercritical Fluid Chromatography. JChromatogr A 505: 169-178.
- Funazukuri T, Kong CY, Murooka N, Kagei S (2000) Measurements of Binary Diffusion Coefficients and Partition Ratios for Acetone, Phenol, a-Tocopherol, and ß-Carotene in Supercritical Carbon Dioxide with A Poly(ethylene glycol)-Coated Capillary Column. IndEngChem Res 39: 4462–4469.
- Kong CY,Funazukuri T, Kagei S (2004) Chromatographic impulse response technique with curve fitting to measure binary diffusion coefficients and retention factors using polymer-coated capillary columns. J Chromatogr A 1035: 177-193.
- Funazukuri T, Kong CY, Kagei S (2004) Impulse response techniques to measure binary diffusion coefficients under supercritical conditions. J Chromatogr A 1037: 411-429.
- Funazukuri T, Kong CY, Kagei S (2006) Binary Diffusion Coefficients in Supercritical Fluids: Recent Progress in Measurements and Correlations for Binary Diffusion Coefficients. J Supercritical Fluids 38: 201-210.
- Kong CY,Funazukuri T, Kagei S, Wang G, Lu F, et al. (2012) Applications of the chromatographic impulse response method in supercritical fluid chromatography. J Chromatogr A 1250: 141-156.
- Funazukuri T, Kong CY, Kagei S (2006) Binary Diffusion Coefficients and Retention Factors for Polar Compounds in Supercritical Carbon Dioxide by Chromatographic Impulse Response Method. J Supercritical Fluids 37: 359-366.
- Kong CY, Nakamura M, Sone K, Funazukuri T, Kagei S (2010) Measurements of Binary Diffusion Coefficients for Ferrocene and 1,1’-Dimethylferrocene in Supercritical Carbon Dioxide. J ChemEng Data 55: 3095–3100.
- Kong CY, Gu YY, Nakamura M, Funazukuri T, Kagei S (2010) Diffusion Coefficients of Metal Acetylacetonates in Supercritical Carbon dioxide. Fluid Phase Equilib 297: 162-167.
- Kong CY,Siratori T, Wang G, Sako T, Funazukuri T (2013) Binary Diffusion Coefficients of Platinum(II) Acetylacetonate in Supercritical Carbon Dioxide. J ChemEng Data 58: 2919-2924.
- Funazukuri T, Kong CY, Kagei S (2002) Infinite-Dilution Binary Diffusion Coefficient, Partition Ratio, and Partial Molar Volume for Ubiquinone CoQ10 in Supercritical Carbon Dioxide. IndEngChem Res 41: 2812-2818.
- Funazukuri T, Kong CY, Kagei S (2003) Binary Diffusion Coefficients, Partition Ratios and Partial Molar Volumes at Infinite Dilution for ß-carotene and a-tocopherol in Supercritical Carbon Dioxide. J Supercritical Fluids 27: 85-96
- Funazukuri T, Kong CY, Kagei S (2004) Effects of Molecular Weight and Degree of Unsaturation on Binary Diffusion Coefficients for Lipids in Supercritical Carbon Dioxide. Fluid Phase Equilib 219: 67-73.
- Kong CY, Withanage NRW, Funazukuri T, Kagei S (2005) Binary Diffusion Coefficients and Retention Factors for Long-Chain Triglycerides in Supercritical Carbon Dioxide by the Chromatographic Impulse Response Method. J ChemEng Data 50: 1635-1640.
- Kong CY, Takahashi N, Funazukuri T, Kagei S (2007) Measurements of Binary Diffusion Coefficients and Retention Factors for Dibenzo-24-Crown-8 and 15-Crown-5 in Supercritical Carbon Dioxide by Chromatographic Impulse Response Technique. Fluid Phase Equilib 257: 223-227.
- Sun CKJ, Chen SH (1985) Diffusion of Benzene, Toluene, Naphthalene, and Phenanthrene in Supercritical Dense 2,3-Dimethylbutane. AIChE J 31: 1904-1910.
- Kopner A, Hamm A, Ellert J, Feist R, Schneider GM (1987). Determination of Binary Diffusion Coefficients in Supercritical Chlorotrifluoromethane and Sulphurhexafluoride with Supercritical Fluid Chromatography (SFC). ChemEngSci 42: 2213-2218.
- Noel JM, Erkey C, Bukur DB, Akgerman A (1994) Infinite Dilution Mutual Diffusion Coefficients of 1-Octene and 1-Tetradecene in Near-Critical Ethane and Propane. J ChemEng Data 39: 920-921.
- Eaton A, Bukur DB, Akgerman A (1995) Molecular Diffusion Coefficients and Effective Diffusivities of 1-Octene in Supercritical Ethane in Relation to Fischer-Tropsch Synthesis. J ChemEng Data 40: 1293-1297.
- Eaton AP, Akgerman A (1997) Infinite-Dilution Diffusion Coefficients in Supercritical Fluids. IndEngChem Res 36: 923-931.
- Sun CKJ, Chen SH (1986) Tracer Diffusion in Dense Ethanol: A Generalizied Correlation for Nonpolar and Hydrogen-Bonded Solvents. AIChE J 32: 1367-1371.
- Sun CKJ, Chen SH (1985) Tracer Diffusion of Aromatic Hydrocarbons in n-Hexane Up to the Supercritical Region. ChemEngSci 40: 2217-2224.
- Olesik SV, Woodruff JL (1991) Liquid Mass-Transport Theories Applied to Molecular Diffusion in Binary and Ternary Supercritical Fluid Mixtures. Anal Chem 63: 670-676.
- Sun CKJ, Chen SH (1987) Tracer Diffusion in Dense Methanol and 2-Propanol up to Supercritical Region: Understanding of Solvent Molecular Association and Development of an Empirical Correlation. IndEngChem Res 26: 815-819.
- Plugatyr A,Svishchev IM (2011) Molecular diffusivity of phenol in sub- and supercritical water: application of the split-flow Taylor dispersion technique. J PhysChem B 115: 2555-2562.