Hexane-soluble extracts

Figure 5. The m/e 206 (a) and TIC (b) chromatograms of Wyodak subbituminous coal (CHCl /hexane soluble extract).

From empirical observation, ILs tend to be immiscible with non-polar solvents. They can therefore be washed or brought into contact with diethyl ether or hexane to extract non-polar reaction products. Among solvents of greater polarity, esters (ethyl acetate, for example) exhibit variable solubility with ILs, depending on the nature of the IL. Polar or dipolar solvents (including chloroform, acetonitrile, and methanol) appear to be totally miscible with all ILs (excepting tetrachloroaluminate IL and the like, which react). Among notable exceptions, [EMIMJCl and [BMIMJCl are insoluble in dry acetone. 

The early work of Sutin and Dodson (85) on neutron-irradiated ferrocene exemplifies the results and problems of recoil chemistry. After dissolving their samples in hexane and extracting with aqueous solutions they isolated, after further purification, radioactive FeCp2 and a species which emerged as ionic iron(III). Adsorbed on the walls of the glass vessels remained another species soluble in acetone which accounted for up to 50-60% of the radioactive iron. This species has not yet been identified. The FeCp2 activity accounted for some 10-12% of the Fe, which increased on standing several weeks at room temperature or 2-3 days at 110° C, as is shown in Table III. 

The most critical decision to be made is the choice of the best solvent to facilitate extraction of the drug residue while minimizing interference. A review of available solubility, logP, and pK /pKb data for the marker residue can become an important first step in the selection of the best extraction solvents to try. A selected list of solvents from the literature methods include individual solvents (n-hexane, " dichloromethane, ethyl acetate, acetone, acetonitrile, methanol, and water ) mixtures of solvents (dichloromethane-methanol-acetic acid, isooctane-ethyl acetate, methanol-water, and acetonitrile-water ), and aqueous buffer solutions (phosphate and sodium sulfate ). Hexane is a very nonpolar solvent and could be chosen as an extraction solvent if the analyte is also very nonpolar. For example, Serrano et al used n-hexane to extract the very nonpolar polychlorinated biphenyls (PCBs) from fat, liver, and kidney of whale. One advantage of using n-hexane as an extraction solvent for fat tissue is that the fat itself will be completely dissolved, but this will necessitate an additional cleanup step to remove the substantial fat matrix. The choice of chlorinated hydrocarbons such as methylene chloride, chloroform, and carbon tetrachloride should be avoided owing to safety and environmental concerns with these solvents. Diethyl ether and ethyl acetate are other relatively nonpolar solvents that are appropriate for extraction of nonpolar analytes. Diethyl ether or ethyl acetate may also be combined with hexane (or other hydrocarbon solvent) to create an extraction solvent that has a polarity intermediate between the two solvents. For example, Gerhardt et a/. used a combination of isooctane and ethyl acetate for the extraction of several ionophores from various animal tissues. 

The EtOH extract of Ipomoea dichroa Choisy was fractionated into different organic solvents. The n-hexane-soluble fraction was resolved by column chromatography to afford dichrosides A-D. The major component dichroside D (hexadecanoic acid, (115)-[(0-6-deoxy-a-L-mannopyranosyl-(1 3)-0-[ S-D-glucopyranosyl-(l—>4)]-0-6-deoxy-a-L-mannopyranosyl-(1 4)-0-6-deoxy-a-L-mannopyranosyl-(l—>2)-6-deoxy-a-L-mannopyranosyl)oxy]) was subjected to catalytic hydrogenation. 

Chloroform extraction of the whole products of dry hydrogenation (400 C 60 min 5% Mo 7 MPa H,) of PSOC-1266 produced a strongly fluorescent extract and non-fIncrescent residue. After drying, the extract was seen under the microscope to contain two components with distinctive fluorescence characteristics (Fig. 7). Component 1 had a fluorescence spectrum very similar to that of the oil (hexane-soluble) fraction of the same... 

Table 4. Effects of varions lipid fractions of chloroform methanol extract (1 1,v/t) (a), acetone- soluble and -insoluble fractions (b), and n-hexane-soluble and -insoluble fractions (c) on tumor volume at 20 d and tumor weight at 21 din sarcoma 180-bearing mice1...

When product made with a 2 1 ratio of BPA to sodium hydroxide was extracted with boiling hexane, a 45% yield of monomer bisphenol-A bischloroformate could be isolated from the hexane-soluble fraction. The GPC curves of the product isolated by the boiling-hexane extraction are shown in Figure 4. The GPC curve indicates that a small amount... 

Et2AlCl Catalyst. Under the same conditions as above 20 grams of PVC and 2 grams of cis-1,4-polybutadiene, prepared with an alkyl-aluminum-titanium tetraiodide catalyst system (95% cis-1,4 content, intrinsic viscosity at 25°C in benzene 2.2) in 200 ml chlorobenzene were allowed to react in the presence of 2 mmoles of Et2AlCl at 5°-10°C for 60 minutes. The reaction product was isolated by precipitation in methanol and dried to yield 22.0 grams of modified poly (vinyl chloride). Hexane extraction under reflux for 24 hours removed 8% of hexane-soluble material. 

Separation of extremely complex mixtures of radiolabeled metabolites in natural products generally requires the use of more than one chromatographic step. The sequence in which the steps are carried out is furthermore crucial to a satisfactory result, and is itself dependent upon the initial prechromatographic separations (7j. We might, for example, expect that our initial biological system had been extracted to give three fractions, any or all of which might contain radioactivity non-polar (hexane-soluble), moderately polar (ethyl acetate-soluble), and very polar (alcohol/water soluble). 

Separations. The asphaltene fractions were obtained by solvent extraction with benzene and subsequent precipitation with cyclohexane. The cyclo-hexane-soluble fractions were separated into saturate, aromatic, and polar aromatic fractions by the clay-gel technique, ASTM D-2007 (modified). This separation is also applicable to asphaltenes. 

Table II. Sequential Extraction of Coals with CHCI3 (Soxhlet), CHCI3 Acetone Methanol, 47 30 23, Azeotrope (Soxhlet) and Separation of Hexane Solubles (Wt% maf Coal, Duplicates were Averaged)...

Total ChCl3 Soluble (Soxhlet) Hexane Soluble Portion of ChCl3 Extract Total Azeotrope Soluble (Soxhlet) Hexane Soluble Portion of Azeotrope Extract... 

Coal Hexane Soluble CHCI3 Extract Liquefaction Product After 13 Recycle Passes... 

Unsaponifiable matter in fats is the ether or hexane-soluble components extracted after a fat sample is refluxed with alcoholic potassium hydroxide. 

The copolymer is isolated by precipitation in hexane and washed with portions of 20-30 ml of hexane until no more hexane-soluble fraction is extracted. 

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