Fractionation, with charcoal column

Manufacture. Trichloromethanesulfenyl chloride is made commercially by chlorination of carbon disulfide with the careful exclusion of iron or other metals, which cataly2e the chlorinolysis of the C—S bond to produce carbon tetrachloride. Various catalysts, notably iodine and activated carbon, are effective. The product is purified by fractional distillation to a minimum purity of 95%. Continuous processes have been described wherein carbon disulfide chlorination takes place on a granular charcoal column (59,60). A series of patents describes means for yield improvement by chlorination in the presence of dihinctional carbonyl compounds, phosphonates, phosphonites, phosphites, phosphates, or lead acetate (61). 

Four 250-ml fractions were collected followed by 150 ml fractions. The residues from fractions B to 16 were combined and rechromatographed over a 125-g column of magnesium silicate. The solumn was eluted with 6% acetone in hexanes which was collected in 150 ml portions. Fractions IB to 29 were combined and dissolved in acetone, decolorized with charcoal, and recrystallized from acetone. One gram of a crystalline mixture of the 7-epimers of 7,17-dimethyltestosterone was obtained melting at 120° to 140°C. 

The method described by Teichman et al. [15] and discussed in section 9.1.1.2 for the determination of chlorinated insecticides and PCBs in soils has also been applied to sediments. The procedure involves adsorption chromatography on alumina and charcoal, elution with increasing fractional amounts of hexane on alumina columns, and with acetonediethyl ether and benzene on charcoal columns. The polychlorobiphenyl and pesticides are then determined by gas chromatography on the separate elutes without interference. 

The methanol extract of the leaves of Cerhera manghas and its fruit contain the iridoids theve-side and theviridoside, as described in [124]. The methanol extract of the leaves, after the addition of water, was sequentially partitioned with chloroform, acetic acid and butanol. This extract and the aqueous phase were submitted to column chromatography with charcoal and water/ methanol as eluent. Theveside was isolated from the aqueous phase. Fractions of the butanol extract, which turn blue after heating with mineral acid, were chromatographed over a silica gel column with a gradient of increasing polarity of chloroform/methanol to afford theviridoside. 

The amide 20 (0.1 mol) was dissolved in AcOH (60 mL), 40% HBr/H20 (60 mL) was added, and the resulting mixture was refluxed for 20 h. After cooling to rt, the solvents were removed in vacuo, the residue was mixed with H20 (50 mL), benzoic acid was removed by filtration, and the soln was clarified with charcoal and loaded onto a Dowex 50W X8 50-100 mesh column (15 x 300mm). The column was washed with H20 and ninhydrin-positive fractions were collected. Concentration yielded pure, crystalline enantiomers of 21 (Table 3). 

Jans son et al. [52] described a multiresidue method for PCA analysis in biological samples by acetone-hexane and diethylether-hexane extraction, oxidation with sulfuric acid to remove lipid, and isolation of PCAs on SX-3 Biobeads GPC. A combination of silica and activated charcoal column chromatography was then used to isolate other OCs. With diethylhexylphthalate (DEHP) as a retention indicator and (1 1) DCM/hexane as the mobile phase for GPC, PCAs were selectively removed from other persistent OCs by collecting an initial fraction that corresponded to a factor times the retention time of DEHP. All other... 

A solution of l-benzoyl-l-bromocyclobutane " (15 g, 0.063 mol) in glacial HOAc (200 mL) containing AgOAc (11.46 mg, 0.068 mol) was refluxed for 4 h (optimum time). After cooling, the mixture was filtered and treated with charcoal and the solvent was evaporated on a rotary evaporator under vacuum. The residue was dissolved in EtjO (25 mL), carefully washed with sat. aq NaHCOj and HjO, dried, and fractionated through a Vigreux column (20 cm) to give the product yield 9.07 g (65%) bp 126-129 °C/0.52 Torr. 

For examination of detailed structural features, elsinan was subjected to partial, acid hydrolysis with 0.5 M sulfuric acid for 4 h at 85°. The degradation products were fractionated by a Charcoal column, followed by preparative, paper chromatography. Table II shows the results of the fractionation. 

For characterization of major oligosaccharides, the enzyme digest was fractionated using a charcoal column, and each sugar fraction eluted with aqueous ethanol (0 to 25%) was purified by preparative paper chromatography (Whatman 3 MM, butanol-pyridine-water, 6 4 3). 

CySs was separated from the culture fluid of R, phaseoli RA-12 according to the method of Higashiura et al. . The culture fluid was centrifuged to remove cells and other insoluble materials, the resulting supernatant was poured onto a charcoal column, and after washing the column with water, adsorbed CySs were desorbed with 30% ethanol. As this fraction still contained impurities, as shown in Figure l-(2), a charcoal column was used again to remove them. The components in the fraction were readsorbed on a charcoal column and CySs were desorbed with 20 ethanol. 

The HA and FA may be fractionated further. Forsyth devised a chromatographic fractionation of FA on a charcoal column and this has been widely used. The column is eluted successively with O.IM HCl,... 

This Crude product (15.8 g) In water (360 ml) was added to a prehydrogenated suspension of 10% palladium on charcoal (4 g) in water (400 ml), and hydrogenation was continued for 30 minutes. The catalyst was removed and the filtrate was adjusted to pH 7.5 with sodium bicarbonate, then evaporated at low temperature and pressure. The residue was purified by chromatography on a column of cellulose powder, eluting first with butanol/ ethanol/water mixture and then with acetone/isopropanol/water. The main fraction was evaporated at low temperature and pressure to give a 32% yield of the sodium salt of a-carboxybenzylpenicillin as a white powder. The product was estimated by manometric assay with penicillinase to be 58% pure. 

Ovaries (100 g) of the pufferfish Fugu vermicularis porphgreus are extracted with 1% acetic acid in methanol. The extract is concentrated in vacuo and defatted by shaking with chloroform. The defatted extract is treated with activated charcoal. The toxin adsorbed is eluted with 1% acetic acid in 20% ethanol. The eluate is evaporated in vacuo to dryness. The residue is dissolved in a small a-mount of water and adjusted to pH 6 with 1 N NaOH. The toxic solution is applied to an Amberlite IRC-50 column (NH, 2.5 x 45 cm) and developed with 2 L of water, and then 1 L each of 1 and 10% acetic acid. The toxic fractions are freeze-dried, dissolved in 1 mL of water and analyzed by HPLC. 

Mark and Saito 31) attempted fractionating polymers by means of chromatography as early as 1936. They filtered solutions of cellulose acetate in acetone through a column with a charcoal-like adsorbent made from blood. The eluate contained the fraction of highest molar mass the rest of the sample was trapped in the column. It could be extracted by dioxane from separated portions of the packing. The largest molecules had travelled farthest. This was in contrast to expectation from Traube s rule and indicated size exclusion. 

The seed is deep-frozen at —30° for at least one month and then extracted twice with 70% aqueous ethyl alcohol. The ethyl alcohol is then removed at low temperature and the residue is separated by buffer into an acid and a nonacid fraction. The crude acid fraction is further fractionated by column chromatography, by procedures similar to those described by West and Phinney (18), First the crude acidic extract is chromatographed on a column of charcoal-Celite, which effectively separates the gibberellins from each other but not from other acids. 

---