Distillation mantle

Place 3 3oz packets of Mildewcide into a 1L flask with an electric heating mantle and cork in the neck connected to a gas bubbler immersed in at least 550mL of distilled water. Heat the paraformaldehyde (what is in the Mildewcide) to between 180-200C (a temp, regulator is absolutely necessary for this step or use a silicone oil bath). The paraformaldehyde will depolymerize making formaldehyde gas in about 91% yield. Alternatively, the gas can be bubbled through the Ammonia solution directly (only for the brave ). If the Formaldehyde solution will not be used immedi-... 

Note 1). The mixture is heated with a mantle with stirring for 32 hr under a 50-cm fractionating column packed with 5-nm glass beads and topped by a Dean-Stark trap. The reaction mixture is then distilled through the packed column. The fraction which boils at 120 -126°C is collected. The yield is 86.0-87.3 g (77-78%) of 2,2-dimethyl-4-pentenal (1) as a clear, colorless oil, n 1.4216 (Note 2). 

The ice bath is replaced, and 250 ml, of ethylene dichloride is added to the mixture. When the internal temperature has been lowered to 5°, a solution of 67 g. (1.0 mole) of freshly distilled pyrrole in 250 ml. of ethylene dichloride is added through a clean dropping funnel to the stirred, cooled mixture over a period of 1 hour. After the addition is complete, the ice bath is replaced with a heating mantle, and the mixture is stirred at the reflux temperature for 15 minutes, during which time there is copious evolution of hydrogen chloride. 

A setup similar to the preceding one is used in this experiment except that provision should be made for heating the reaction vessel (steam bath, oil bath, or mantle). Lithium aluminum hydride (10 g, 0.26 mole) is dissolved in 200 ml of dry -butyl ether and heated with stirring to 100°. A solution of 9.1 g (0.05 mole) of ra j-9-decalin-carboxylic acid (Chapter 16, Section I) in 100 ml of dry -butyl ether is added dropwise over about 30 minutes. The stirring and heating are continued for 4 days, after which the mixture is cooled and water is slowly added to decompose excess hydride. Dilute hydrochloric acid is added to dissolve the salts, and the ether layer is separated, washed with bicarbonate solution then water, and dried. The solvent is removed by distillation, and the residue is recrystallized from aqueous ethanol, mp 77-78°, yield 80-95 %. 

By the procedure described in the preceding experiment, 30 g (0.11 mole) of tri-phenylphosphine dissolved in 100 ml of acetonitrile is converted to triphenylphosphine dibromide. After the addition of the bromine has been completed, the cooling bath is removed, the flask is set up for vacuum distillation, and the solvent is removed. To the residue is added /7-chlorophenol (10.3 g, 0.08 mole), and the flask is heated at 200° (mantle, wax bath, or sand bath) until HBr ceases to be evolved (about 2 hours). The flask is cooled and the contents are steam distilled affording crude / -chlorobromo-benzene in about 90% yield. Recrystallization from benzene gives the pure product, mp 65-66°. 

Neutral alumina (12 g) is placed in a 250-ml flask and partially deactivated by the addition of 0.12 g (2-3 drops) of water. The alumina is allowed to stand with occasional swirling for 30 minutes. To the flask is added 20 g of 1,4-cyclohexanediol (Chapter 5, Section II). A short Vigreux column is placed over the flask, which is then arranged for distillation. The mixture is heated at 240° with a sand bath or mantle, whereupon distillation commences (caution, bumping). The distillation is continued until the alumina is dry (5-8 hours). The distillate, which consists of two layers, is added to 75 ml... 

The carbonyl compound to be reduced (0.1 mole) is placed in a 250-ml round-bottom flask with 13.5 g of potassium hydroxide, 10 ml of 85% hydrazine hydrate, and 1(X) ml of diethylene glycol. A reflux condenser is attached and the mixture is heated to reflux for I hour (mantle). After refluxing 1 hour, the condenser is removed and a thermometer is immersed in the reaction mixture while slow boiling is continued to remove water. When the pot temperature has reached 200°, the condenser is replaced and refluxing is continued for an additional 3 hours. The mixture is then cooled, acidified with concentrated hydrochloric acid, and extracted with benzene. The benzene solution is dried, and the benzene is evaporated to afford the crude product, which is purified by recrystallization or distillation. 

A mixture of cyclohexanone (11.8 g, 0.12 mole), ethylene glycol (8.2 g, 0.13 mole), /j-toluenesulfonic acid monohydrate (0.05 g), and 50 ml of benzene is placed in a 250-ml round-bottom flask fitted with a water separator and a condenser (drying tube). The flask is refluxed (mantle) until the theoretical amount of water (approx. 2.2 ml) has collected in the separator trap. The cooled reaction mixture is washed with 20 ml of 10 % sodium hydroxide solution followed by five 10-ml washes with water, dried over anhydrous potassium carbonate, and filtered. The benzene is removed (rotary evaporator) and the residue is distilled, affording l,4-dioxaspiro[4.5]decane, bp 65-67713 mm, 1.4565-1.4575, in about 80% yield. 

A 250-ml round-bottom flask is charged with a mixture of cyclohexanone (14.7 g, 0.15 mole), morpholine (15.7 g, 0.18 mole), and / -toluenesulfonic acid monohydrate (0.15 g) in 50 ml of toluene. The flask is fitted with a water separator and a condenser and is brought to reflux (mantle). The separation of water begins immediately and the theoretical amount (2.7 ml) is obtained in about 1 hour. Without further treatment, the reaction mixture may then be distilled. After removal of the toluene at atmospheric pressure, the product is obtained by distillation at reduced pressure, bp II8-I207IO mm, 1.5122-1.5129, in about 75% yield. 

In a 500-ml round-bottom flask fitted with a condenser, and a heating mantle is placed a mixture of 25 g of diethyl 5-(l -carboxy-2 -oxocyclohexyl)valerate, 70 g of barium hydroxide, and 200 ml of methanol, and the mixture is refluxed for 24 hours. After cooling, the mixture is acidified (pH 4) by cautious addition of cold 10% aqueous hydrochloric acid. The acidified solution is saturated with sodium chloride and then extracted three times with 100-ml portions of chloroform. The combined chloroform extracts are dried (anhydrous magnesium sulfate) and evaporated. On vacuum distillation, the residue affords the product (about 15 g), bp 176-17870.5 mm. 

The ketoester is mixed in a suitable round-bottom flask with excess 6 N sulfuric acid. The flask is fitted with a condenser and a mantle, and the mixture is refluxed gently for 3-4 days. The cooled reaction mixture is extracted with ether, the ether is washed with bicarbonate solution and water, then dried, and the solvent is evaporated. On distillation, the residue affords 2-methylcyclooctanone, bp 97-98718 mm, 86712 mm, 1 4656,... 

A 500-ml, three-necked, round-bottom flask is equipped with a condenser, a dropping funnel, and a thermometer in the reaction mixture. In the flask is placed a mixture of 85% hydrazine (115 ml, 118 g) and 225 ml of 95% ethanol with a few boiling chips. The solution is brought to reflux (mantle) and cinnamaldehyde (100 g, 0.76 mole) is added dropwise over about 30 minutes followed by an additional 30 minutes of refluxing. A still head is attached to the flask and volatiles (ethanol, water, hydrazine hydrate) are slowly distilled at atmospheric pressure until the pot temperature reaches 200° (about 3 hours). Hereafter, phenylcyclopropane is collected over the range 170-180°. When the pot temperature exceeds 250°, the recovery is complete. The crude product (55-65 g) is washed twice with 50-ml portions of water and dried (anhydrous potassium carbonate). Distillation under vacuum through a short column affords the product, bp 60°/13 mm, 79-80°/37 mm, n f 1.5309, about 40 g (45%). 

Heating mantles are particularly designed for the heating of flasks and find wide application in distillation operations. For details of the distillation procedure and description of the apparatus employed a textbook of practical organic chemistry should be consulted.9... 

B. l-Bromo-2-fluorobenzene. Cautionl This step should be carried outm a hood because the PFS evolved on thermal decomposition of the diazonium salt is poisonous. The apparatus consists of a 1-1., three-necked, round-bottomed flask equipped with a thermometer, a condenser, a magnetic stirrer (optional), and a 250-ml. Erlenmeyer flask that is attached by means of a short rubber Gooch connecting tube. The dry powdered hexafluorophosphate salt is placed in the Erlenmeyer flask, and 300 ml. of heavy mineral oil is placed in the round-bottomed flask. The mineral oil is heated to 165-170° by means of an oil bath or electric heating mantle and maintained at this temperature while the salt is added rapidly in portions over a period of 30 minutes. The flask is cooled rapidly to room temperature, the side flask is removed, and 400 ml. of 10% aqueous sodium carbonate is added slowly through the condenser. The mixture is steam-distilled until no more oil is visible in the distillate. 

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