Cooling with acetone

A Neslab LILT-80 refrigerated circulating bath was used. Alternatively, a Dewar condenser cooled with acetone-dry ice can be used. 

Solutions of freshly prepared (Z)-ethene-l, 2-dithiol (1.84 g, 20 mmol) and trisulfur dichloride (3.34 g, 20mmol), each in Et20 (100 mL), were added at an equal rate to EtzO (1.5L) over 6 8 h with stirring under N2. The mixture was further stirred for several hours and then evaporated, leaving an orange oil which contained 80% of pentathiepin. The oil was purified by distillation at rt in vacuo and condensing the distillate in a trap cooled with acetone/solid C02. Small amounts of the pure product were obtained as yellow drops. 

D20 (11 g) is added slowly to a vigorously stirred Grignard solution from magnesium turnings (24 g) and butyl bromide (100 g) in dibutyl ether (400 ml). The mixture is then heated and the deuterated butane is collected in a cold trap at —78°. Distillation of the crude product through a Davis column, whose head is cooled with acetone/dry ice at —10°, affords [1-DiJ-butane (27.6 g, 85.2%), which boils at —0.5 to —0.2°/740 mm. 

The apparatus shown in Fig. 235 is connected to a vacuum pump. The thick-wall Pyrex ampoule a contains 10 g. of Gelg. After evacuation, 2.1 ml. (4.8 g.) of CH3I is allowed to distill from the graduated vessel b into the ampoule, which is cooled with acetone-Dry Ice mixture. The ampoule a is now sealed at the neck and heated for 24 hours at 110°C. (Caution danger of explosion, particularly at the beginning. If the ampoule is too weak.)... 

Cooling with acetone 17, 88 Conjugated double bonds... 

Cooling with acetone. A soln. of l,5-cyclo6ctadiene in methanol hydrogenated with 5%-Pd-calcium carbonate at 2 atm. until 1 molar equivalent of Hg has been absorbed cfs-cyclooctene. Y 87%.—The heat of reaction is conveniently dissipated by wrapping the bottle with a towel and periodically saturating it with acetone. P. D. Gardner and M. Narayana, J. Org. Chem. 26, 3518 (1961). 

Introduce 197 g. of anhydrous brucine or 215 g. of the air-dried dihydrate (4) into a warm solution of 139 g. of dZ-acc.-octyl hj drogen phthalate in 300 ml. of acetone and warm the mixture vmder reflux on a water bath until the solution is clear. Upon cooling, the brucine salt (dA, IB) separates as a crystalline solid. Filter this off on a sintered glass funnel, press it well to remove mother liquor, and wash it in the funnel with 125 ml. of acetone. Set the combined filtrate and washings (W) aside. Cover the crystals with acetone and add, slowly and with stirriug, a slight excess (to Congo red) of dilute hydrochloric acid (1 1 by volume about 60 ml.) if the solution becomes turbid before the introduction of... 

Apparatus 3-1 round-bottomed, three-necked flask, provided with a dropping funnel, a mechanical stirrer and a reflux condenser, cooled with dry-ice and acetone (cold finger). The upper end of this condenser was connected with a drying tube filled with anhydrous calcium chloride. 

Geraniol [106-24-1] M 154.3, b 230 , d 0.879, n 1.4766. Purified by ascending chromatography or by thin layer chromatography on plates of kieselguhr G with acetone/water/liquid paraffin (130 70 1) as solvent system. Hexane/ethyl acetate (1 4) is also suitable. Also purified by GLC on a silicone-treated column of Carbowax 20M (10%) on Chromosorb W (60-80 mesh). [Porter Pure Appl Chem 20 499 7969.] Stored in full, tightly sealed containers in the cool, protected from light. 

Potassium iodide [7681-11-0] M 166.0, pK -8.56 (for HI). Crystd from distilled water (0.5mL/g) by filtering the near-boiling soln and cooling. To minimise oxidation to iodine, the crystn can be carried out under N2 and the salt is dried under vacuum over P2O5 at 70-100°. Before drying, the crystals can be washed with EtOH or with acetone followed by pet ether. Has also been recrystallised from water/ethanol. After 2 recrystns ACS/USP grade had Li and Sb at <0.02 and <0.01 ppm resp. 

Sodium azide [26628-22-8] M 65.0, m 300°(dec, explosive), pK 4.72 (for HN3). Crystd from hot water or from water by the addition of absolute EtOH or acetone. Also purified by repeated crystn from an aqueous solution saturated at 90° by cooling it to 10°, and adding an equal volume of EtOH. The crystals were washed with acetone and the azide dried at room temperature under vacuum for several hours in an... 

A suspension of lithium aluminum deuteride (1.6 g) in dry tetrahydrofuran (60 ml) is added dropwise to a stirred and cooled (with ice-salt bath) solution of 5a-androst-l4-ene-3j3,17j3-diol (179, 1.6 g) and boron trifluoride-etherate (13.3 g) in dry tetrahydrofuran (60 ml). The addition is carried out in a dry nitrogen atmosphere, over a period of 30 min. After an additional 30 min of cooling the stirring is continued at room temperature for 2 hr. The cooling is resumed in a dry ice-acetone bath and the excess deuteriodiborane is destroyed by the cautious addition of propionic acid. The tetrahydrofuran is then evaporated and the residue is dissolved in propionic acid and heated under reflux in a nitrogen atmosphere for 8 hr. After cooling, water is added and the product extracted with ether. The ether... 

A mixture consisting of 0.69 g (10.5 mmoles) of zinc-copper couple, 12 ml of dry ether, and a small crystal of iodine, is stirred with a magnetic stirrer and 2.34 g (0.7 ml, 8.75 mmoles) of methylene iodide is added. The mixture is warmed with an infrared lamp to initiate the reaction which is allowed to proceed for 30 min in a water bath at 35°. A solution of 0.97 g (2.5 mmoles) of cholest-4-en-3/ -ol in 7 ml of dry ether is added over a period of 20 min, and the mixture is stirred for an additional hr at 40°. The reaction mixture is cooled with an ice bath and diluted with a saturated solution of magnesium chloride. The supernatant is decanted from the precipitate, and the precipitate is washed twice with ether. The combined ether extracts are washed with saturated sodium chloride solution and dried over anhydrous sodium sulfate. The solvent is removed under reduced pressure and the residue is chromatographed immediately on 50 g of alumina (activity III). Elution with benzene gives 0.62 g (62%) of crystalline 4/5,5/5-methylene-5 -cholestan-3/5-ol. Recrystallization from acetone gives material of mp 94-95° Hd -10°. 

The enamine (1 g) in 30 ml of benzene and 5 ml of toluene is treated, with cooling, with a solution of 0.33 g (1.04 eq.) of perbenzoic acid in 2.1 ml of benzene. The reaction is complete in a few minutes. Ether (30 ml) is added, then the solution is washed with 2 N sodium hydroxide and with water to neutrality, dried over sodium sulfate and evaporated under reduced pressure. Crystallization from acetone gives 0.51 g of crude product mp 230°. One further crystallization from methanol gives 0.38 g (50%) of 3J5,17a-dihydroxy-5a-pregnan-20-one rap 265°. 

Irradiations of Testosterone Acetate (114), —In t-Butanol. 1.25 g of (114) in 250 ml t-butanol is irradiated for 32 hr at 30° under nitrogen with a Hanau Q81 high-pressure mercury lamp placed in a central water-cooled Pyrex immersion well with acetone filter. The solvent is evaporated in vacuo and the residue chromatographed on 125 g silica gel with benzene-ethyl acetate (4 1) to yield 0.29 g 17 -hydroxy-la,5 -cyclo-10a-androstan-2-one acetate [(118) 23%] mp 164-165°, after crystallization from acetone-hexane [a]i3 37 (CHCI3) 0.14 g cyclopentanone (120) (11%) mp 106-107° [aJo 38° (CHCI3) and 0.58 g starting material [(114) 46%]. Ratio (118) (120) - 2 1. 

Figure 9.3 Potassium sulphate crystals formed by. a) cooling, (h) drowning-out with acetone Jones etai, 1987)...

This section deals with the procedure used by American Polymer Standards Corp. in the manufacture of GPC/SEC gels. The reaction is performed in a three-neck flask equipped with a reflux condenser, a mechanical stirrer, and a thermometer. First, prepare the water phase and then the organic phase. After mixing the organic phase into the water phase, stir at 300 to 400 rpm for 2 hr at 40°C. Heat to 70°C and continue mixing at 150 rpm for 10 hr. Cool to room temperature, (RT), dilute with water, and filter. Wash the gel with water, acetone, toluene, and again with acetone. Dry at 70°C for 12 hr, classify the gel, and package. 

After the reaction is completed, the mixture should be cooled to RT and diluted with water. The gel should separate by floating up. If this does not happen the organic solvents need to be steam distilled off first. Filter off the floating gel and wash it with water, acetone, toluene, and again with acetone. 

A -Octalone-2 An 8.5-g (0.058 mole) portion of the above octalone mixture is dissolved in 50 ml of 60-90° petroleum ether in a 125-ml Erlenmeyer flask and cooled in a Dry Ice-acetone bath for 1 hour. zJ -Octalone-2 crystallizes and is collected by suction filtration through a jacketed sintered-glass funnel, which is cooled with Dry Ice-acetone. The residue is washed with cold (—78°) petroleum ether, transferred rapidly to a clean 125-ml Erlenmeyer flask, and the crystallization and filtration steps are repeated. The residue, after the second filtration, is transferred to a small round-bottom flask, brought to room temperature (the solid melts), and distilled. By this procedure, about 5 g (34%) of purified zl" -octalone-2, bp 143-145°/15 mm, is obtained. The purified material contains 1-3% of the -isomer. 

Chloro-2-(3-methyl-4H-1,2,4-triazol-4-yDbenzophenone (Oxidation of 7solution prepared by adding sodium periodate (2 g) to a stirred suspension of ruthenium dioxide (200 mg) in water (35 ml). The mixture became dark. Additional sodium periodate 18 g) was added during the next 15 minutes. The ice-bath was removed and the mixture was stirred for 45 minutes. Additional sodium periodate (4 g) was added and the mixture was stirred at ambient temperature for 18 hours and filtered. The solid was washed with acetone and the combined filtrate was concentrated in vacuo. The residue was suspended in water and extracted with methylene chloride. The extract was dried over anhydrous potassium carbonate and concentrated. The residue was chromatographed on silica... 

About 14 g of choline chloride are stirred with a solution of about 20 g of phosgene in 100 g of chloroform for about two hours at room temperature. The mixture becomes a two-phase liquid mixture. Hydrochloric acid and excess phosgene are removed by distillation in vacuo. Chloroform is added to the syrup, and the mixture is then added to a solution of excess ammonia in chloroform which was cooled with solid carbon dioxide-acetone. The mixture is... 

---