Chromatography separating funnel

Picer and Picer [357] evaluated the application ofXAD-2, XAD-4, and Tenax macroreticular resins for concentrations of chlorinated insecticides and polychlorinated biphenyls in seawater prior to analysis by electron capture gas chromatography. The solvents that were used eluted not only the chlorinated hydrocarbons of interest but also other electron capture sensitive materials, so that eluates had to be purified. The eluates from the Tenax column were combined and the non-polar phase was separated from the polar phase in a glass separating funnel. Then the polar phase was extracted twice with n-pentane. The -pentane extract was dried over anhydrous sodium sulfate, concentrated to 1 ml and cleaned on an alumina column using a modification of the method described by Holden and Marsden. The eluates were placed on a silica gel column for the separation of PCBs from DDT, its metabolites, and dieldrin using a procedure described by Snyder and Reinert [359] and Picer and Abel [360]. 

In a 50-mL, two-necked flask, 100 mg (0.3 mmol) of octacarbonyl dicobalt, Co2(CO)8, is dissolved in 10 mL of toluene. Then 400 mg (0.7 mmol) tppts is dissolved in 10 mL water and added to the solution. The reaction mixture is stirred for 3 h at room temperature. During the reaction the organic phase is decolorized, whereas the water phase turns brown. The mixture is transferred to a separation funnel while maintaining exclusion of oxygen. After the phases have separated, the organic phase is washed twice, in each case with 5 mL of water, and the combined aqueous phases are washed twice, in each case with 5 mL of toluene. The organic phases are discarded. The water phases are collected and the solvent is removed in a vacuum. The crude product is purified by column chromatography on Sephadex G-25. Yield 370 mg (81%) brown powder. 

Method B. In a Schlenk tube 100 mg (0.11 mmol) of chlorotris(triphenyl-phosphine)rhodium(I), ClRh[P(C6H5)3]3, is dissolved in a mixture of 20 mL of toluene and 10 mL of tetrahydrofuran. Then 20 mL of an aqueous solution of 1.87 g (3.3 mmol) of tppts is added to this solution to form a lower layer. After 12 h of vigorous stirring, the reaction mixture is transferred to a separation funnel. The aqueous phase is separated and washed twice, in each case with 5 mL of methylene chloride. The organic phases are discarded. The pure compound is obtained by column chromatography of the water phase on Sephadex G-15. Yield 180 mg (82%). 

Method C. 100 mg (0.4 mmol) of bis[/z-chloro l,2,5,6-> 4-cyclooctadiene (l,5) rhodium], [RhCl(>74-C8H12)]23, is dissolved in 10 mL of methylene chloride and 0.68 g (1.2 mmol) of tppts in 10 mL of water is added. The two-phase system is stirred intensively for 30 min. Then the reaction mixture is transferred to a separation funnel. The aqueous phase is separated and the organic phase extracted twice, in each case with 5 mL of water. The combined aqueous phases are then washed twice with methylene chloride (2x5 mL). The water solution is transferred into a round-bottomed flask and the solvent is removed in a vacuum (10 2 torr). The raw product obtained is sufficiently pure for most reactions. Depending on the stoichiometry, small amounts of tppts or (>74-C8H12)Rh2(/r-Cl)2(tppts)2 are present, which can be removed by column chromatography on Sephadex G-15. Yield 740 mg (93%) red glass-like solid. 

It was put into a separating funnel and shook with 1 L ethyl acetate and 200 ml of 5% sodium hydroxide. The an organic layer was separated, with 2-3 L water washed (portions 400-500 ml), dried over sodium sulfate and distilled in vacuum to dryness at about 60°C. 121.2 g crude proscillaridin-2,3-ethyl orto-formiate yielded. It was dissolved in 1 L dimethylformamide, mixed with 200 ml methyl iodide and stirred with 20 g 55-60% suspension of sodium hydride at 20°C for 1 hour. 14 L ethyl acetate was added, 5 times with 1-2 L water shook and the organic layer was distilled to 1/4 of volume. The solution of proscillaridin-2,3-ethyl ortho-formiate-4-methyl ester obtained (about 1 L) was mixed with 2 L 0.002 N HCI and stood for 2 hours at 20°C. Then it was neutralized with 0.1 N sodium hydroxide and distilled in vacuum to about 1 L. The solution was shook with 2 L chloroform and 1 L water, organic layer was separated, water layer was 2 times was extracted with still 1 L chloroform and the pooled organic phase dried over sodium sulfate. Then the solvent was removed and 147 g of obtained product was purified by chromatography on silica gel in system chloroform/acetone 4 1. 

Figure 4-1. Separation equilibria. Separation in a separating funnel (left) in which a compound is distributed differentially between two immiscible phases, and analogous behaviour in a chromatography column (right) where a compound exhibits differing affinities to the stationary and the mobile phases.

This mixture is shaken in a separating funnel and allowed to stand overnight. It will separate into a concentrated aceiic acid phase in equilibrium with cyclohexane, and a layer composed essentially of cyclohexane. To prepare a descending chromatogram the lower layer in the separating funnel is run off the next day and poured into the bottom of the chromatography... 

Water was added to quench the reaction. The reaction mixture was poured into a separating funnel, extracted with diethyl ether and dried over magnesium sulfate. The magnesium sulfate was removed by filtration using a filter paper. The filtrate was then dried over silica. The product was purified by column chromatography using silica gel and a 10% ethyl acetate/hexanes solution (0.85 g, 85% yield). 

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