Supercritical Gas Extraction Research Articles

Antioxidant activity of Smoke Shield in-vitro and in-vivo.

Smoke Shield is a proprietory formulation containing extract of turmeric (Curcuma longa), obtained by supercritical carbon dioxide gas extraction and post-supercritical hydroethanolic extraction, together with extracts of green tea and other spices whose presence synergistically increases the activity of turmeric. This study evaluates the antioxidant potentials of Smoke Shield in-vitro and in experimental animals, as well as in human models. Smoke Shield was found to scavenge superoxide radicals generated by photoreduction of riboflavin (50% inhibitory concentration = 91 microg mL(-1)) and hydroxyl radicals generated by Fenton reaction (50% inhibitory concentration = 95 microg mL(-1)) and reduced lipid peroxidation. Administration of Smoke Shield to mice was found to elevate antioxidant enzymes such as catalase and superoxide dismutase in blood as well as in liver and kidney. Glutathione-S-transferase activity was found to be significantly elevated in liver and kidney of animals treated with Smoke Shield. Glutathione levels were also significantly elevated in blood. Glutathione reductase was significantly elevated in kidney. Administration of Smoke Shield decreased the lipid peroxidation in serum, liver and kidney, as well as reduced the levels of conjugated dienes and hydroperoxides. Administration of Smoke Shield to smokers was found to increase the superoxide dismutase and glutathione in blood and decrease glutathione peroxidase. Smoke Shield inhibited phase I enzymes as represented by aniline-hydroxylase and aminopyrenedemethylase in-vitro. These results indicate that Smoke Shield has potent antioxidant activity, could inhibit phase I enzymes and increase detoxifying enzymes, which makes it an effective chemoprotective herbal formulation.

Exploration for unknown substances in rapeseed oil that shorten survival time of stroke-prone spontaneously hypertensive rats: Effects of super critical gas extraction fractions

To identify the causative substances for the shortening of survival time by rapeseed (Canola) oil in stroke-prone spontaneously hypertensive rats (SHRSP), SHRSP were fed on a standard chow supplemented with 10 w/w% soybean oil (control), rapeseed oil, one of the fractions of rapeseed oil obtained by super critical gas extraction (SCE) under a pressure of 180-bar or 350-bar, at 40 °C, or the residue from the extraction (with 0.5% NaCl in drinking water). In another series of experiment, SHRSP were fed for 8 weeks on the above-mentioned diets without salt loading and autopsied. Fatty acid compositions in these diets were similar, except in the soybean oil diet, and phytosterol contents were: (diet containing) 180-bar fraction > residue > rapeseed oil > 350-bar fraction > soybean oil. Survival times in the rapeseed oil, 350-bar fraction and residue groups were shorter than, whereas that in the 180-bar fraction was similar to in the soybean oil group. In the 8-week feeding experiment, chronic nephropathy was found frequently in the groups other than the soybean oil group. The heart weights were higher in the rapeseed oil and residue groups. Cerebral necrosis was found in the residue group. Taken together, the followings are concluded, (1) Neither the fatty acid composition, nor the amount of phytosterols in the diets appeared to be decisive in the shortening of life. (2) SCE appeared to produce a safe (180-bar) fraction, though it failed to separate clearly the causative substances into specific fractions. (3) The factors that facilitate the genetic disease of SHRSP appear to exist in rapeseed oil. However, they might not be identical to those responsible for the life-shortening, since there were no findings common across the rapeseed oil, 350-bar and residue groups, which showed similar life-shortening.

05/00592 Supercritical gas extracts from low-quality coals: on the search of new precursors for carbon materials

05/00592 Supercritical gas extracts from low-quality coals: on the search of new precursors for carbon materials

An Ounce of Prevention from a Ton of Tomatoes

Tomato processors enhancing the health of consumers with their nutrient-rich tomato extract soon may enhance the health of their communities as they adopt a new, green technique for producing the precious substance. A team of researchers from the University of Florida (UF) has developed an extraction method using supercritical carbon dioxide (CO2), which may provide a cleaner way to get more extract from more tomatoes. Companies that produce tomato extract and pure lycopene (the carotenoid that gives tomatoes their red color) typically use chemical solvents to draw the compounds from tomatoes. One of the most commonly used solvents is ethyl acetate. Although nontoxic, ethyl acetate is highly flammable and must be removed from the extract through distillation. “The advantage of supercritical extraction is that we use carbon dioxide,” says Murat Balaban, a professor of food engineering at the UF Institute of Food and Agricultural Sciences and leader of the research team. “Neither the remaining tomato nor the extract need to be cleaned of solvent as in the case of ethyl acetate, because carbon dioxide . . . is easily separated from them.” Supercritical extraction does not produce CO2, which is associated with global warming; it only uses it. “This is another wonderful example of how people are using green chemistry to shift from traditional technology,” says Paul Anastas, director of the Green Chemistry Institute in Washington, D.C. “Nothing is as innocuous as carbon dioxide.”

Supercritical gas extracts from low-quality coals: on the search of new precursors for carbon materials

This paper studies the chemical composition of several supercritical gas (SCG) extracts and its influence on the thermal behaviour under carbonisation conditions. The extracts were obtained from a Spanish lignite (Mequinenza), a low-quality coal from the point of view of energy applications. The lignite was treated with toluene, ethanol (EtOH) and tetrahydrofuran (THF) as solvents under different supercritical temperature and pressure conditions. The extracts display high aliphatic nature and enhanced concentrations of oxygen functional groups, aided by the contribution of hydrogenation and oxygen incorporation reactions occurring in the SCG extraction with EtOH and THF. Thiophenic compounds are also present in great concentrations derived from the exceptionally high organic sulphur content of the parent coal. The carbonisation of the extracts renders anisotropic material with fine mosaic texture, as a consequence of the significant thermal reactivity inferred by the aliphatic and oxygenated groups. The size of the mosaic increases with the temperature of the SCG extraction and varies with the supercritical solvent in the order: toluene<EtOH<THF.

Supercritical gas extracts from low-quality coals: on the search of new precursors for carbon materials

This paper studies the chemical composition of several supercritical gas (SCG) extracts and its influence on the thermal behaviour under carbonisation conditions. The extracts were obtained from a Spanish lignite (Mequinenza), a low-quality coal from the point of view of energy applications. The lignite was treated with toluene, ethanol (EtOH) and tetrahydrofuran (THF) as solvents under different supercritical temperature and pressure conditions. The extracts display high aliphatic nature and enhanced concentrations of oxygen functional groups, aided by the contribution of hydrogenation and oxygen incorporation reactions occurring in the SCG extraction with EtOH and THF. Thiophenic compounds are also present in great concentrations derived from the exceptionally high organic sulphur content of the parent coal. The carbonisation of the extracts renders anisotropic material with fine mosaic texture, as a consequence of the significant thermal reactivity inferred by the aliphatic and oxygenated groups. The size of the mosaic increases with the temperature of the SCG extraction and varies with the supercritical solvent in the order: toluene<EtOH<THF.

Liquefaction of Biomass by Supercritical Gas Extraction

Verbascum and sunflower stalks mill were converted to liquid products by using organic solvents (methanol, ethanol, and acetone) with catalysts (%10 NaOH) and without catalysts in an autoclave at temperatures of 533 and 573 K for verbascum and 523 and 563 K for sunflower.The liquid products were extracted by liquid-liquid extraction (benzene and diethyl ether). The yields from supercritical methanol, ethanol, and acetone conversions were 44.4, 43.3, and 60.5 (at 573 K for verbascum stalk) and 40.0, 45.6, and 47.8% (at 563 K for sunflower stalk), respectively. In the catalytic runs with methanol and ethanol, extracts were 52.4 and 44.8 (at 553 K for verbascum stalk) and 58.5 and 54.2% (at 563 K for sunflower stalk), respectively.

Liquefaction of Prangmites australis by supercritical gas extraction

Prangmites australis Mill was converted to liquid products by using organic solvents (methanol and ethanol) with catalyst (10% NaOH) and without catalyst in an autoclave at temperatures of 523 and 563 K. The liquid products were extracted by liquid-liquid extraction (benzene and diethyl ether). The yields from supercritical methanol and ethanol coversions were 38.7 and 53.6%, respectively, at 563 K. In the catalytic runs with methanol and ethanol the extracts were 44.2 and 57.6%, respectively, at 563 K. The yields from supercritical methanol were increased from 37.3 to 44.2% as the temperature was increased from 523 to 563 K in the catalytic run.

96/00637 Liquefaction of hazelnut seed coat by supercritical gas extraction

96/00637 Liquefaction of hazelnut seed coat by supercritical gas extraction

95/05876 Effect of preswelling on soxhlet and supercritical gas extraction of a Turklsh lignite

95/05876 Effect of preswelling on soxhlet and supercritical gas extraction of a Turklsh lignite

95/06016 Supercritical-gas extraction of some Turkish lignite with different solvents

95/06016 Supercritical-gas extraction of some Turkish lignite with different solvents

Regeneration Methods for Caffeine-Loaded CO2

Abstract Supercritical gas extraction for the decaffeination of green coffee beans has become an established method in the last decade. However, because of the commercial aspects in this field, few research results on applications have been published. In this publication, three different methods for the regeneration of caffeineloaded CO2 are presented: depressurization, adsorption with activated carbon, and absorption with water. For all these methods, phase equilibrium experiments with pure caffeine were done. Furthermore, pilot-plant experiments were performed to decaffeinate green coffee beans.

Liquefaction of hazelnut seed coat by supercritical gas extraction

Supercritical fluid extracts of hazelnut seed coat were obtained using solvents (methanol, ethanol and acetone) and methanol and ethanol containing sodium hydroxide (10%) catalyst. The yields of supercritical methanol, ethanol and acetone extractions were 41.9, 52.3 and 60.9%, respectively, at 563 K. The yield of supercritical acetone extraction has been increased from 44.0 to 60.9% as the temperature increased from 523 to 563 K. The yield of supercritical methanol extraction has been increased from 41.9 to 60.0% in the catalytic run.

CHEMICALS FROM FOREST PROOUCTS BY EFFICIENT EXTRACTION METHODS

Abstract Treatment of air dried and ground wood samples with different solvents at different temperatures and pressures gave yields of extracts which increased from 6.8 to 16.2 % as the pressure of the extraction increased from 6.0 to 17.5 MPa by supercritical-gas extraction. The samples suspended in water or water-solvent mixture containing alkaline catalysts (sodium carbonate, sodium hydroxide or sodium zincate) have been converted completely or partly to on oil, water-soluble chemicals and gases if subjected to heat in on autoclave. The yields of catalytic extraction have been increased from 14.3 to 42.5 % as the temperature increased from 438 to 603°K

Calculations of compressed carbon dioxide viscosities

Compressed carbon dioxide is widely used as a solvent in supercritical and liquefied gas extraction. The knowledge of the fluid-phase viscosity as a function of temperature and pressure is indispensable for predicting the hydrodynamics and mass-transfer rates in these processes. Various equations, both generally valid and especially derived for carbon dioxide, are compared with published experimental data covering gas, liquid, and supercritical regions. The equation of Vesovic et al. and of Altunin and Sakhabetdinov are recommended as most reliable for predicting the viscosity of dense carbon dioxide.

Structural characterization of residues from supercritical gas extraction of brown coal

Residues from supercritical gas extraction of brown coal with toluene and butanol were studied by proximate and ultimate analyses, optical microscopy and X-ray diffractometry. The type of solvent appeared to have a decisive influence on the yield, properties and structure of the residues produced in the range 380–440 °C. The residues from extraction with toluene had a microstructure and structural ordering similar to those of the raw coal. Extraction with butanol gave caked and optically anisotropic residues with a relatively high degree of structural ordering.

A spectroscopic study of structural changes occurring in supercritical gas extraction of a Spanish lignite with alcohols

Supercritical gas (SCG) extraction of a Spanish lignite was conducted with methanol and ethanol in a semicontinuous mode at temperatures between 250 and 350 °C and pressures up to 15.2 MPa. The resultant extracts and residues were characterized principally by FT-i.r. spectroscopy and n.m.r. to specifically provide information on the mode and extent of solvent incorporation via secondary reactions. FT-i.r. and n.m.r. revealed that alkylation and esterification reactions both occur to a significant extent. The extent of alkylation increases with increasing temperature and SCG extractions with 13C-labelled methanol demonstrated that the incorporated methyl groups are mainly bound to C atoms but also to O, S and N atoms. The extent of esterification is incomplete, as indicated by the presence of free carboxylic acids in both the chars and extracts, and decreases with increasing temperature due to the competing effect of decarboxylation reactions.

Supercritical gas extraction of Polish brown coals

Properties of nine selected samples of Polish brown coals from both strip mines and perspective deposits varying in lithotype have been determined. This involved technical analysis of the elementary, group and petrographie compositions. The coals were extracted with supercritical toluene at 410 °C and 13 M Pa. The humic acid content and humodetrinite content were found to be well correlated with the yield of coal extract. The optimal conditions of gas extraction for a selected coal sample were determined.

Supercritical Carbon Dioxide Extraction of Long‐Chain Aliphatics from Two Soils

AbstractCurrent trends in soil organic‐matter research are focused on developing methods for the extraction of specific organic‐matter components. One such method is the supercritical gas extraction of soils using CO2. To examine the applicability of this approach to whole soils, we used supercritical CO2 for extracting two soils. The resulting extracts were analyzed by chemical methods, infrared (IR), 13C nuclear magnetic resonance (NMR), and by field‐ionization and field‐desorption mass spectrometry. Major components identified in the extracts were C15 to C41 n‐alkanes, the C8 alkene, the C29 n‐alcohol, C14 to C40 n‐fatty acids, C17 to C41 unsaturated fatty acids, the C18 and C26 dioic acids, the C28 and C30 n‐ketones, C38 to C64 n‐alkyl monoesters, the C52 n‐dioic acid dimer, and the C78 n‐dioic acid trimer. Of special interest was the presence in the extracts of 10‐nonacosanol (C29), a biomarker for coniferous epicuticular waxes. Supercritical CO2 was found to be a mild and specific extractant for the removal of long‐chain aliphatic materials from soils.

石炭液化油成分の蒸気圧ならびに臨界定数

Coal liquids have received much attention recently as useful raw materials since they contain polycyclic aromatic compounds and heterocyclic compounds. Supercritical gas extraction is expected as one of the successful separation techniques to separate and purify them.In design of such a separation process, physical properties of coal-derived components, i.e., sublimation pressures, solid molar volumes, critical temperatures, critical pressures, critical molar volumes, the Pitzer's acentric factors, and the Stiel's polar factors are needed. The authors surveyed these properties from literature and handbooks. If no experimental critical properties are reported, they are estimated by the Lydersen's group-contribution method. Solubility parameters that are useful to evaluate molecular interaction are also compiled.