Preparation of phosphorus tribromide phosphorus tribromide: A 500 ml three-necked flask, fitted with a mechanical stirrer, a dropping funnel and a reflux condenser, 28 grams of pure red phosphorus, and 200 ml of dry carbon tetrachloride (dried over anhydrous calcium chloride) are placed. 198 grams (or 63.5 ml) of dry bromine are placed in the dropping funnel and added to the vigorously stirred mixture of red phosphorus in tetrachloromethane at the rate of about few drops per second. After all the bromine has been added, the reaction mixture is refluxed for 15 minutes at 80-90° C. The clear solution is then…
Author: Ethan Frank
A Guide to Successfully Hiring a Digital Marketing Agency When you are looking at hiring a digital marketing agency, there may be lots of questions you want to answer. You may also be unsure about what process to follow or even where to start. To get the most out of those digital efforts, you must choose an agency that understands your business and aims. Decide What You Want and Need Knowing what you want to achieve is important. Before you start contacting agencies, you are going to need to establish what you need and want. For instance, are you looking…
Preparation of succinimide 20 g of succinic acid are dissolved in a small quantity, of water in a basin, and the solution neutralised with ammonia. The solution is boiled to expel excess of ammonia, after which a further 20 g of succinic acid dissolved in water are added. The solution is evaporated to complete dryness on a water bath; the dry residue is transferred to a retort and heated quickly with a large luminous flame. The sublimate of succinimide is recrystallised from pure acetone. Yield 70%, colourless rhombic plates; m.p. 126° C; b.p. 288° C. Systematic organic chemistry, by W. M.…
Preparation of Pyridinium Tribromide Pyridinium Tribromide: To the 1 liter round bottom flask equipped with a reflux condenser and a dropping funnel 79.1 g of pyridine were placed, and while cooling the flask with ice-water, slowly from a dropping funnel 113 ml of 48% hydrobromic acid was added. Then, the reflux condenser is removed and replaced with distillation head. Water was distilled under vacuum by heating the flask in an oil or glycerol bath to 160 ° C. Pyridinium Tribromide: After distillation the flask should remain completely dry with pyridine hydrobromide, which in the same flask were completely dissolved by…
Preparation of Ammonium Chromate A saturated solution of ammonium chromate is treated with an excess of concentrated ammonium hydroxide solution until the strong smell of ammonia appears and the color of the solution changes from orange to yellow. Then the reaction mixture is cooled in ice water, the obtained yellow crystals of ammonium chromate are filtered, washed with cold concentrated ammonium hydroxide solution and dried at room temperature. 100 grams of chromium trioxide are dissolved in 70 ml of water. The mixture is stirred until solution is complete and then the flask is cooled with ice water. 160 ml of the…
Preparation of methyl formate Methyl formate is prepared by the action of methyl alcohol saturated with hydrochloric acid on calcium formate. To the round-bottom flask equipped with dropping funnel and a reflux condenser, the latter being connected with a well-cooled descending condenser 100 g of calcium formate are placed. 130 ml methyl alcohol saturated with hydrogen chloride (methanol could absorb up to 40 % of hydrogen chloride) are placed in the dropping-funnel and added to the calcium formate. When all the methanol has been added, the mixture is allowed to stand for a short time and then methael formate is…
Preparation of 1 4 dimethoxybenzene 1 4 dimethoxybenzene: The 1 mole of hydroquinone (benzene-1,4-diol, quinol) is treated rapidly with stirring, in a three-necked flask provided with a reflux condenser, stirrer, internal thermometer, and dropping funnel, with 2.5 mole of 10% sodium hydroxide. With vigorous stirring, 2 mole of dimethyl sulfate is added in such a way that the temperature remains below 40° C (water cooling). To complete the reaction and to destroy unchanged dimethyl sulfate, the mixture is then heated for 30 min on a boiling water bath. After cooling the solid reaction product is isolated by filtration, washed with…
Preparation of Phenyl Acetate Phenyl Acetate: 15 g of phenol are dissolved in 105 ml (1.6 moles) of 10% aqueous sodium hydroxide solution, and the solution is cooled by adding about 150 g of crushed ice. Then 22 ml (or 24 g) of acetic anhydride is added, the flask is stoppered and is shaken vigorously for about 5 minutes. When the emulsion of phenyl acetate is obtained the reaction is complete. The mixture is poured into a separating-funnel, owing to the density of the acetate being only slightly greater than that of water, a sharp separation is usually not rapidly obtained.…
Preparation of Diphenylmethanol Diphenylmethanol: The reaction flask is attached to a short reflux condenser through which, however, no water flows, instead is filled with methanol. The upper end of the reflux condenser is fitted to a small, water-cooled, descending condenser and a receiver. The reaction flask is charged with 18.2 g of benzophenone and a solution of 20 g of aluminum isopropoxide dissolved in 100 ml of dry 2-propanol. The reaction mixture is heated on a water-bath so that 5-10 drops pass over per minute. After 30-60 min no more acetone is detectable in a sample of the distillate. If…
Preparation of Mesitylene Mesitylene: 400 g of clean dry sand are placed in a 2ooo ml retort connected with a condenser. 250 g of acetone are added, and then a cooled mixture of 560 g of concentrated sulfuric acid and 150 g of water is run in, in a slow continuous stream, the retort being meantime cooled in cold water. After 24 hours standing, the mixture is slowly distilled, directly or in steam. When oily drops appear in the neck of the retort, the receiver is changed, and the distillate collected until only very small quantities of the oil appear. The…