Sodium hydroxide pellets

Pyridine. The analytical reagent grade pyridine will satisfy most requirements. If required perfectly dry, it should be refluxed over potassium or sodium hydroxide pellets or over barium monoxide, and then distilled with careful exclusion of moisture (compare Fig. 77, 47, 2). It is hygroscopic, and forms a hydrate of b.p. 94-5°. Pure pyridine has b.p. 115-5°/760 mm. 

An alternative method of working up the distillate, which has its advantages when dealing with volatile ketones or when it is suspected that conversion into the ketone is incomplete, is to treat the combined ketones with sodium hydroxide pellets until the mixture is alkaline. Should solids separate, these may be dissolved by the addition of a little water. The ketone is then separated, dried over anhydrous potassium carbonate, and fractionated. 

IsoValeric acid. Prepare dilute sulphuric acid by adding 140 ml. of concentrated sulphuric acid cautiously and with stirring to 85 ml. of water cool and add 80 g. (99 ml.) of redistilled woamyl alcohol. Place a solution of 200 g. of crystallised sodium dicliromate in 400 ml. of water in a 1-litre (or 1-5 litre) round-bottomed flask and attach an efficient reflux condenser. Add the sulphuric acid solution of the isoamyl alcohol in amaU portions through the top of the condenser shake the apparatus vigorously after each addition. No heating is required as the heat of the reaction will suffice to keep the mixture hot. It is important to shake the flask well immediately after each addition and not to add a further portion of alcohol until the previous one has reacted if the reaction should become violent, immerse the flask momentarily in ice water. The addition occupies 2-2-5 hours. When all the isoamyl alcohol has been introduced, reflux the mixture gently for 30 minutes, and then allow to cool. Arrange the flask for distillation (compare Fig. II, 13, 3, but with the thermometer omitted) and collect about 350 ml. of distillate. The latter consists of a mixture of water, isovaleric acid and isoamyl isovalerate. Add 30 g. of potassium not sodium) hydroxide pellets to the distillate and shake until dissolved. Transfer to a separatory funnel and remove the upper layer of ester (16 g.). Treat the aqueous layer contained in a beaker with 30 ml. of dilute sulphuric acid (1 1 by volume) and extract the liberated isovaleric acid with two... 

To obtain a maximum yield of the acid it is necessary to hydrolyse the by-product, iaoamyl iaovalerate this is most economically effected with methyl alcoholic sodium hydroxide. Place a mixture of 20 g. of sodium hydroxide pellets, 25 ml. of water and 225 ml. of methyl alcohol in a 500 ml. round-bottomed flask fitted with a reflux (double surface) condenser, warm until the sodium hydroxide dissolves, add the ester layer and reflux the mixture for a period of 15 minutes. Rearrange the flask for distillation (Fig. II, 13, 3) and distil off the methyl alcohol until the residue becomes pasty. Then add about 200 ml. of water and continue the distfllation until the temperature reaches 98-100°. Pour the residue in the flask, consisting of an aqueous solution of sodium iaovalerate, into a 600 ml. beaker and add sufficient water to dissolve any solid which separates. Add slowly, with stirring, a solution of 15 ml. of concentrated sulphuric acid in 50 ml. of water, and extract the hberated acid with 25 ml. of carbon tetrachloride. Combine this extract with extract (A), dry with a httle anhydrous magnesium or calcium sulphate, and distil off the carbon tetrachloride (Fig. II, 13, 4 150 ml. distiUing or Claisen flask), and then distil the residue. Collect the wovaleric acid 172-176°. The yield is 56 g. 

Cool the solution in ice while the alkali hydroxide is dissolving some ammonia gas is evolved. When the potassium hydroxide has dissolved, separate the amine, and dry it for 24 hours over sodium hydroxide pellets. Filter into a Claisen flask and distil. Collect the di-n-butylamine at 157-160°. The yield is 31 g. 

If pure 3-bromo-4-aminotoluene is required, the crude base may be purified either by steam distillation or, more satisfactorily, by distillation under reduced pressure. The oil is dried with 5 g. of sodium hydroxide pellets, and distilled under reduced pressure from a Claisen fiask with a fractionating side arm a little p-tolui-dine may be present in the low boiling point fraction, and the pure substance is collected at 92-94°/3 inin. or at 120-122°/30 mm. The purified amine solidifies on cooling and melts at 17-18°. 

Liberate the free base by adding to the phenylhydrazine hydrochloride 125 ml. of 25 per cent, sodium hydroxide solution. Extract the phenyl-hydrazine with two 40 ml. portions of benzene, dry the extracts with 25 g. of sodium hydroxide pellets or with anhydrous potassium carbonate thorough drying is essential if foaming in the subsequent distillation is to be avoided. Most of the benzene may now be distilled under atmospheric pressure, and the residual phenylhydrazine under reduced pressure. For this purpose, fit a small dropping funnel to the main neck of a 100 ml. Claisen flask (which contains a few fragments of porous porcelain) and assemble the rest of the apparatus as in Fig. II, 20, 1, but do not connect the Perkin triangle to the pump. Run in about 40 ml. of the benzene, solution into the flask, heat the latter in an air bath (Fig. II, 5, 3) so that... 

In a 500 ml. three-necked flask, equipped with a thermometer, mechanical stirrer and efficient reflux condenser, dissolve 16 g. of sodium hydroxide pellets in 95 ml. of hot methyl alcohol. Add 49 g. of guanidine nitrate, stir the mixture at 50-65° for 15 minutes, and then cool to about 20°. Filter oflF the separated sodium nitrate and wash with two 12 ml. portions of methyl alcohol. Return the combined filtrates to the clean reaction flask, add 69 g. of sulphanilamide (Section IX,9) and stir at 50-55° for 15 minutes. Detach the reflux condenser and, with the aid of a still-head ( knee-tube ), arrange the apparatus for distillation from an oil bath with stirring about 100 ml. of methyl alcohol are recovered. Add 12 g. of pure cycZohexanol. Raise the temperature of the oil bath to 180-190° and continue the distillation. Reaction commences with the evolution of ammonia when the uiternal temperature reaches 145°. Maintain the... 

A mixture of 66.5 g. (0.5 mole) of tetrahydroquinoline and 400 g. of trimethylene chlorobromide (Note 1) is placed in a 1-1. round-bottomed flask attached to a reflux condenser, and heated in an oil bath held at 150-160° for 20 hours (Note 2). The reaction mixture is cooled, a solution of 50 ml. of concentrated hydrochloric acid in 500 ml. of water is added, and the excess trimethylene chlorobromide is removed by distillation with steam (Note 3). The acid residue from the steam distillation is made alkaline with a 40% solution of sodium hydroxide (about 75 ml.), and the julolidine is extracted with two 150-ml. portions of ether. The ethereal solution is washed with ISO ml. of water and dried over sodium hydroxide pellets. The ether is evaporated and the residue distilled under reduced pressure. The portion that boils at 105-110°/ mm. is collected (Notes 4 and 5). The yield is 67-70 g. (77-81%). 

If the pump is a filter pump off a high-pressure water supply, its performance will be limited by the temperature of the water because the vapour pressure of water at 10°, 15°, 20° and 25° is 9.2, 12.8, 17.5 and 23.8 mm Hg respectively. The pressure can be measured with an ordinary manometer. For vacuums in the range lO" mm Hg to 10 mm Hg, rotary mechanical pumps (oil pumps) are used and the pressure can be measured with a Vacustat McLeod type gauge. If still higher vacuums are required, for example for high vacuum sublimations, a mercury diffusion pump is suitable. Such a pump can provide a vacuum up to 10" mm Hg. For better efficiencies, the pump can be backed up by a mechanical pump. In all cases, the mercury pump is connected to the distillation apparatus through several traps to remove mercury vapours. These traps may operate by chemical action, for example the use of sodium hydroxide pellets to react with acids, or by condensation, in which case empty tubes cooled in solid carbon dioxide-ethanol or liquid nitrogen (contained in wide-mouthed Dewar flasks) are used. 

B. Tropohne. In a 1-1., three-necked, round-bottomed flask equipped with a mechanical stirrer, addition funnel, and reflux condenser are placed 500 ml. of glacial acetic acid and then, cautiously, 100 g. of sodium hydroxide pellets. After the pellets have dissolved, 100 g. of 7,7-dichlorobicyclo[3.2.0]hept-2-en-6-one is added and the solution is maintained at reflux under nitrogen for 8 hours. Concentrated hydrochloric acid is then added until the mixture is about pH 1 approximately 125 ml. of acid is required. After the addition of 1 1. of benzene, the mixture is filtered and the solid sodium chloride is washed with three 100-ml. portions of benzene. The two phases of the filtrate are separated and the aqueous phase is transferred to a 1-1. continuous extractor (Note 8) which is stirred magnetically. The combined benzene phase is transferred to a 2-1. pot connected to the extractor and the aqueous phase is extracted for 13 hours. Following distillation of the benzene, the remaining orange liquid is distilled under reduced pressure... 

Blue tetrazolium Sodium hydroxide pellets Methanol... 

Dipping solution First dissolve 10 mg potassium hexacyanoferrate(III) and then 1 g sodium hydroxide pellets in 7 ml water and then dilute the solution with 20 ml ethanol. 

Dipping solution II Dissolve 2 g sodium hydroxide pellets in 2 ml water with heating and make up to 100 ml with methanol. 

A 100 gallon lined jacketed kettle provided with cooling is charged with 100 lb of benzyl-amine and 150 liters of water. The mixture is cooled to 5°C and with stirring 119 lb of /3-chloropropionyl chloride and a solution of 45 lb of sodium hydroxide pellets in 40 liters of water are added simultaneously at such a rate that the temperature does not exceed 10°C. During this period the pH of the mixture should be on the alkaline side but below pH 9.5. When the addition is complete the pH should be about 8. The mixture is stirred overnight in the cold, and the solid product is filtered. The filter cake is reslurred with about BO gallons of water, filtered, and air-dried. Yield, 12B pounds. 

A mixture of B g (0.0356 mol) of p-(2.2-dichlorocyclopropyl)phenol, 11.2 g (0.2B mol) of sodium hydroxide pellets, 11 g of chloroform and 350 ml of acetone was prepared at 0°C. The cooling bath was removed, the mixture stirred for a minute and then heated on a steam bath to reflux temperature. The reaction mixture was stirred at reflux for three hours and then concentrated in vacuo. The residual gum was partitioned between dilute hydrochloric acid and ether, and the ether layer was separated, dried and concentrated in vacuo. The residual oil (14 g) was partitioned between dilute aqueous sodium bicarbonate and ether. The sodium bicarbonate solution was acidified with concentrated hydrochloric acid and extracted with ether. The ether solution was dried over anhydrous sodium sulfate and concentrated. The residue (9.5 g of yellow oil) was crystallized twice from hexane to give 6.0 g of 2-[p-(2,2-dlchlorocyclopropyDphenoxyl -2-methyl propionic acid in theformof apalecream[Pg.347]

A mixture of 200 parts of p-chlorophenol, 1,000 parts of acetone and 360 parts of sodium hydroxide pellets is heated under reflux and 240 parts of chloroform are gradually added at such a rate that the mixture continues to reflux without further application of heat. 

A mixture of 20 g of 1 -bromo-3,5-dimethyladamantane, 75 ml of acetonitrile, and 150 ml of concentrated sulfuric acid was allowed to react overnight at ambient room temperature. The red reaction product mixture was poured over crushed ice, and the white solid which precipitated was taken up in benzene and the benzene solution dried over sodium hydroxide pellets. The benzene solution was filtered from the drying agent and evaporated to dryness in vacuo to yield 1 B.2 g of product having a melting point of about 97°C and identified by infrared spectrum as 1-acetamido-3,5-dimethvladamantane. 

Rinse sodium hydroxide pellets rapidly with deionised water this removes the carbonate from the surface. A solution prepared from the washed pellets is satisfactory for most purposes. 

The following is an alternative method of preparation. Dissolve lOOg mercury(II) iodide and 70g potassium iodide in 100mL ammonia-free water. Add slowly, and with stirring, to a cooled solution of 160 g sodium hydroxide pellets (or 224 g potassium hydroxide)in 700 mL ammonia-free water, and dilute to 1 L with ammonia-free distilled water. Allow the precipitate to settle, preferably for a few days, before using the pale yellow supernatant liquid. 

Sodium tetrahydroborate (III) (sodium borohydride ), 1 per cent w/v. Dissolve sodium hydroxide pellets (5.0g) in 300 mL of de-ionised water and cool. Add sodium tetrahydroborate(III) (5.0 g) directly to the sodium hydroxide solution and make up the total volume to 500 mL with de-ionised water. Shake the solution thoroughly and filter through a Whatman No. 541 filter paper. (The resulting solution is stable for at least one week.)... 

Occasionally the odor of hydrogen cyanide can be detected during the distillation, even when a trap filled with sodium hydroxide pellets precedes the usual trap cooled in dry ice and acetone to protect the pump. For safety, the vacuum pump should be placed in a hood, or provision should be made for the pump exhaust to be vented into a hood or out-of-doors during the distillation. 

Spray solution 1 Dissolve 10 g sodium hydroxide pellets in 100 ml water. 

Sodium hydroxide, pellets 4-Nitrobenzenediazonium tetrafluoroborate Diethylene glycol Ethanol Methanol Acetone... 

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