Supercritical alcohol extraction

Szekely, E., Simandi, B., Fogassy, E., Kemeny, S., and Kmecz I. Enantioseparation of chiral alcohols by complex formation and supercritical fluid extraction Chirality 2003, 15, 783-786. 

Cumin oil is usually obtained by steam distillation of the milled spice hydrodiffusion gives a higher yield and, more recently, supercritical gaseous extraction is claimed to give oil closer to the aroma and taste of the spice (Eikani et al., 1999). The yields of cumin seed oil with steam distillation are 2.3-3.6%, with liquid carbon dioxide it is 4.5% and with ethanol it is 12%. The major components are cuminaldehyde, cuminyl alcohol, p-mentha and 1.3-dien-7-al, the minimum perceptible levels being at 0.2 ppm. Naik et al. (1989) reported that liquid C02 extraction was quicker than steam distillation for the quantitative extraction of cumin oil without loss of active flavour components, at 58 bar and 20°C. 

Nguyen et al. (1991) extracted ole-oresin from vanilla beans with 2—62 g C02/g dried bean at 306—309 K and 10-13 MPa. Vanillin yields of up to 95% were attained. Vanillin purity was higher with supercritical C02 extraction than with conventional aqueous ethanol extraction, with vanillin representing 74-97% of the flavour and fragrance compounds, compared with 61% using alcohol extraction. 

In another method, developed by Jacobucd and co-workers (9), alcohol is removed by supercritical CO2 extraction in a semi-continuous system. 

Introducing adsorbents into a supercritical fluid extraction system is an alternative attractive method to improve the selectivity for the citrus oil processing. Several applications using silica gel as adsorbent have been reported in the last decade [1-3]. Yamauchi and Saito [3] fractionated lemon peel oil into 3 fractions with gradual increase in pressure by supercritical fluid chromatography, where terpene rich fraction, ester rich, and alcohol and aldehyde rich fraction were obtained at 10 MPa, 20 MPa, and 20 MPa with ethanol as a cosolvent,... 

EO/mole of parent alcohol and then gradually declined. Somewhat different behavior was observed using supercritical COj-extracted stock tank oil which had a higher carbon number 26 vs 16), a higher asphaltene content (1.52% vs 0.78%), and a higher combined acid and base number (0.85% vs 0.33) than the unextracted oil (see above). The maximum foam volume was observed at a lower ethylene oxide content (for 15 20 moles of EO vs 30 moles of EO for unextracted oil). The decline in foam volume with further increases in EO content was much more rapid in the presence of COj-extracted oil. This behavior was also observed for 5 alcohol ethoxyl-ates and Cg alcohol ethoxylates. 

D. Semiond, S. Dautraix, M. Desage, R. Majdalani, H. Casablanca, J.L. Brazier (1996) Identification and isotopic analysis of safranal from supercritical fluid extraction and alcoholic extracts of saffron. Anal. Lett. 22, 1027-1039... 

Lee CH, Row KH, Lee YW, Kim JD, Lee YY. Supercritical fluid extraction of perillyl alcohol in Korean orange peel. J Liquid Chromatogr Related Technol 2001 24 1987-1996. 

Emulsion Drying. Supercritical CO2 extracts the water and organic solvent (a heavy alcohol or ketone) and the same recycle system as proposed for the antisolvent process is applicable. The dilference is that, much lower fluid/substrate ratios, of the order of magnitude of 10 -10 are required, with the resulting savings in the recycle loop. 

Ronyai, E., Simandi, B., Tomoskozi, S., Deak, A., Vigh, L. andWeinbrenner, Z. (1998) Supercritical fluid extraction of com germ with carbon dioxide ethyl alcohol mixture. J. Supercrit. Fluids, 14, 7 5—81. 

CO2 in n-hexadecane, and similarly for hydrocinnamaldehyde. Additionally the concentrations of all components that result in complete miscibility or in three-component two-phase regions can be obtained. Francis reported on 464 ternary systems that included compounds ranging from simple hydrocarbons, alcohols, esters, and aldehydes to much more complex substituted aromatics and heterocyclics. The breadth and importance of his contributions cannot be overestimated, yet, apparently his work was quite frequently not consulted for its relevance a number of research groups subsequently "rediscovered that certain separations were not advantageously carried out by supercritical fluid extraction relative to processing by distillation. 

Reyes T, Bandyopadhyay S, McCoy B (1989) Extraction of lignin from wood with supercritical alcohols. J Supercrit Fluids 2(2-3) 80-84... 

Propolis cannot be used as raw material, it has to be purified by either extraction with alcoholic solvents or supercritical fluid extraction. Depending on the geographical source and extraction processes, propolis extracts may differ... 

Alcohol reflux extraction, ultrasound assisted extraction, Soxhlet extraction and supercritical fluid extraction (SPE) are the main teehniques used to isolate triterpenoids from Cornus spp. fimits [Zhao et al., 2005], Thin layer chromatography (TEC), HPLC and cyclodextrin-modified micellar eleetrokinetie ehromatography (CD-MEKC) have also been apphed for separation and determination of these three triterpenic acids in Iriiits [Zhang et al., 2005 Wang et al., 2008]. The isolated triterpenie compounds and their glycosides were identified by speetroscopie analysis NMR, IR and MS. 

Hexane extraction of stabilized rice bran has been the most commonly used method for obtaining rice bran oil. Hexane has the advantage of high oil recovery, but safety concerns regarding hexane have led to a search for alternative extraction methods. Less hazardous approaches such as the use of isopropyl alcohol, supercritical fluid extraction, or enzyme-assisted extraction are potential alternative processing methods. 

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