Recrystallization water aspirator

The faucet on the water aspirator should be turned on full blast This should suck down the filter paper, which you now wet with some of the cold recrystallization solvent. This will make the paper stick to the plate. You may have to push down on the Buchner funnel a bit to get a good seal between the rubber adapter and the funnel. 

In a hood, through a rapidly stirred suspension of 76 gm (0.396 mole) of cyclohexanoneazine in 300 ml of petroleum ether (b.p. 60°-90°C) cooled to —60°C is passed a slow stream of gaseous chlorine until a slight excess of the gas is noted. The excess of chlorine is removed by ventilation at the water aspirator. Then the solution is concentrated to half-volume by gentle evaporation at reduced pressure. The reaction system is filtered free from tarry impurities and the filtrate is allowed to stand for 24 hr at room temperature. The product gradually separates out and is isolated by filtration. Evaporation of the mother liquor may afford another crop of product. The total yield is 81.5 gm (78 %). The product, after recrystallization from petroleum ether, has a melting point of 66°C. (NOTE Since aliphatic azo compounds are inherently unstable and may serve as free radical sources, the stability of the product should always be checked with due precautions, and excessive exposure to heat should always be avoided.)... 

A still purer product is obtained if the dried petroleum ether solution is evaporated to dryness with a water aspirator and the residual crude product distilled through a Vigreux column After a small fore-run, pure tetramethyl-3,4-dichlorocyclobutene distils at 59-60° at 12 mm. The product melts at 58° and is more stable at room temperature than the recrystallized but undistilled material... 

Ozonolysis of cis-3,4-Dimethyl-3 -hexene. A solution of cis-3,4-di-methyl-3-hexene (98% pure, Chemical Samples Co.) (1.12 grams, 10 mmoles) in 50 ml pentane was ozonized at — 62°C until the blue color of excess ozone was evident. A nitrogen stream was used to purge the solution of excess ozone. Pentane was then carefully distilled off at atmospheric pressure. A water aspirator (20 mm Hg) was then used to remove the ketone product. Treatment of this material with 10 ml of an 0.1 M solution of 2,4-dinitrophenylhydrazine gave 2.33 grams of crude 2,4-dinitrophenylhydrazone. The crude product was recrystallized and identified as the 2,4-dinitrophenylhydrazone of methyl ethyl ketone, mp 115-116°C. Yield of the ketone was 92% based on olefin used. 

The mixture is cooled to room temperature and then added, with vigorous stirring, to an Erlenmeyer flask containing cold water (300 ml). In a separating funnel (500 ml), the solution is washed with dichloromethane (2 X 75 ml). The aqueous layer is collected and acidified with hydrochloric acid (150 ml of 20%). The white precipitate is collected by filtration at the water aspirator, washed with water and dried at 60°C. The product is purified by recrystallization from toluene. ... 

Apparatus for recrystallization, Erlenmeyer flask, Buchner flask, funnel, and water aspirator... 

Preparation-. All glass equipment is dried in an oven at 150°C, assembled while hot (use heat-resistant gloves), and allowed to cool under an atmosphere of dry nitrogen. Pyrrole is dried by distilling under reduced pressure (water aspirator) from calcium hydride immediately before use. p-Toluenesulfonyl chloride is recrystallized from petroleum ether (60-80°C fraction). ... 

The mixture is decanted into an Erlenmeyer flask, the residual green salts are washed with two 15-ml portions of acetone, and the washings are added to the main acetone solution. Cautiously, sodium bicarbonate (approx. 13 g) is added to the solution with swirling until the pH of the reaction mixture is neutral. The suspension is filtered, and the residue is washed with 10-15 ml of acetone. The filtrate is transferred to a round-bottom flask and concentrated on a rotary evaporator under an aspirator while the flask temperature is maintained at about 50°. The flask is cooled and the residue transferred to a separatory funnel, (If solidification occurs, the residue may be dissolved in ether to effect the transfer.) To the funnel is added 100 ml of saturated sodium chloride solution, and the mixture is extracted with two 50-ml portions of ether. The ether extracts are combined, washed with several 5-ml portions of water, dried over anhydrous magnesium sulfate, and filtered into a round-bottom flask. The ether may be distilled away at atmospheric pressure (steam bath) or evaporated on a rotary evaporator. On cooling, the residue should crystallize. If it does not, it may be treated with 5 ml of 30-60° petroleum ether, and crystallization may be induced by cooling and scratching. The crystalline product is collected by filtration and recrystallized from aqueous methanol. 4-r-Butylcyclohexanone has mp 48-49° (yield 60-90 %). 

A mixture of 100 g (0.6 mole) of 1-morpholino-l-cyclohexene, 28.8 g (0,4 mole) of /3-propiolactone, and 100 ml of chlorobenzene is placed in a 500-ml round-bottom flask fitted with a condenser (drying tube). The mixture is refluxed for 4 hours. The solvent and excess enamine are removed by distillation at aspirator pressure. (The residue may be distilled to afford the pure morpholide, bp 187-18871 rnm, 1.5090.) Basic hydrolysis may be carried out on the undistilled morpholide. To the crude amide is added 400 ml of 10% sodium hydroxide solution. The mixture is cautiously brought to reflux, and refluxing is continued for 2 hours. The cooled reaction mixture is made acidic (pH 4) and is extracted three times with ether. The combined ether extracts are washed twice with 5 % hydrochloric acid solution and twice with water. The ethereal solution is dried (sodium sulfate), then filtered, and the solvent is removed (rotary evaporator). The residue may be recrystallized from petroleum ether-benzene, mp 64°. 

Bicyclof 3.3.1 ]nonane-2,6-dione (10) A solution of 10 g of Meerwein s ester, 30 ml of glacial acetic acid, and 20 ml of 6 A hydrochloric acid is heated under reflux for 10 hours. The solution is then carefully distilled under aspirator pressure until all volatile materials (water and acetic acid) are removed. The solid residue is distilled at 129-131°/4 mm to afford the product. It may be recrystallized from benzene giving about 3 g of bicyclo-[3.3.1]nonane-2,6-dione, mp 138-140°. 

C. 7-Methoxyphthalide (4). The crude product from Step B (26.9 g), in a 1-L, one-necked, round-bottomed flask with a magnetic stirring bar, is dissolved in 465 mL of absolute methanol (Note 12). To this solution, cooled to 0°C, is added 7.4 g (0.20 mol) of powdered sodium borohydride, in small portions (Note 13), and the mixture is stirred at room temperature for 18 hr. The reaction mixture is cooled in an ice water bath and taken to pH 4-5 with about 35 mL of 6 M aqueous hydrochloric acid. A further 48 mL (0.288 mol) of 6 M hydrochloric acid is added, the flask is fitted with a reflux condenser and the reaction mixture is heated under reflux for 12 hr. The reaction mixture is then allowed to cool to room temperature and most of the methanol is evaporated under aspirator pressure. The residue is dissolved in 400 mL of methylene chloride, the phases are separated, and the organic fraction is washed with saturated ammonium chloride (3 x 200 mL) and water (1 x 100 mL), dried over anhydrous magnesium sulfate, and concentrated under reduced pressure. The pale yellow solid is recrystallized from ethyl acetate-hexane (1 1) (Note 10) to give 15.4 g... 

Telluraxanthene Bis(2-bromophenyl)methane (3.33 g, 1.02 mmol) is dissolved in 300 tuL of absolute diethyl ether and, under dry nitrogen, 22 mL (36.1 mmol) of a 15% solution of n-butyllithium in hexane are added dropwise. The mixture is heated under reflux for 0.5 h, cooled to 20°C and 1.8 g (14.1 mmol) of finely powdered tellurium are added. The resultant mixture is heated under reflux for 2 h and then poured into ice/water. The mixture is extracted with chloroform, the extract is filtered and the solvent is evaporated in a rotatory evaporator at 20°C under aspirator vacuum. The residue is recrystallized from diethyl ether/petroleum ether after addition of activated charcoal. Yield 1.42 g (47%) m.p. 151°C. 

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