Water, acid warmed

Add 1 g. of the compound to 4 ml. of concentrated sulphuric acid and cautiously introduce, drop by drop, 4 ml. of fuming nitric acid. Warm the mixture on a water bath for 10 minutes, then pour it on to 25 g. of crushed ice (or 25 ml. of ice water). Collect the precipitate by filtration at the pump, and recrystallise it from dilute alcohol. 

In a 1 litre flask mix 53 -5 g. of p-toluidine and 400 ml. of water, and then add cautiously 98 g. (53 6 ml.) of concentrated sulphuric acid warm until the p-toluidine dissolves. Cool the flask in a bath of ice and salt to 0-5° add about 100 g. of crushed ice to the contents of the flask in order to accelerate the cooling. Add slowly and with frequent shaking a solution of 35 g. of sodium nitrite in 60 ml. of water until a slight excess of sodium nitrite is present (.see Section IV,60) keep the temperature of the mixture below 10°. 

Azlactone of a-acetylaminocinnamic acid. Warm a mixture of 29 g. of acetylglycine, 39-5 g. (37 -5 ml.) of redistilled benzaldehyde (Section IV,115), 15 g. of anhydrous sodium acetate and 67 g. (62 ml.) of acetic anhydride (95 per cent.) in a 500 ml. conical flask (equipped with a reflux condenser) on a water bath with occasional stirring until solution is complete (10-20 minutes). Boil the resulting solution for 1 hour, cool and leave in a refrigerator overnight. Stir the sohd mass of yellow crystals with 60 ml. of cold water, transfer to a Buchner funnel and wash well with cold water. (If the odour of benzaldehyde is stih apparent, wash with a little ether.) Recrystallise from carbon tetrachloride or from ethyl acetate-hght petroleum. The yield of azlactone, m.p. 150°, is 35 g. 

Diethylbarbituric acid. In a dry 250 ml. distilling flask, fitted with a thermometer reaching to within 3-4 cm. of the bottom and a condenser, place 51 g. of clean sodium and add 110 g. (140 ml.) of super-dr ethyl alcohol (Section 11,47,5). When all the sodium has reacted, introduce 20 g. of ethyl diethylmalonate and 7 0 g. of dry imea (dried at 60 for 4 hours). Heat the flask in an oil bath and slowly distil off the ethyl alcohol. As soon as the temperature of the liquid reaches 110-115°, adjust the flame beneath the bath so that the contents of the flask are maintained at this temperature for at least 4 hours. Allow the flask to cool somewhat, add 100 ml. of water and warm until the solid (veronal-sodium) dissolves. Pour the solution into a beaker, and add a further 100 ml. of water but containing 7 0 ml. of concentrated siilplmric acid this will hberate the veronal from the sodium derivative. The veronal usually crystallises out if it does not, add a few more drops of dilute sulphuric acid until the solution is acid to Congo red. Heat the contents of the beaker, with stirring and the addition of more water if necessary, until all the veronal dissolves at the boiling point. Allow the hot solution to cool, filter off the crystals of veronal and diy in the air. The yield is 12 g., m.p. 190°. 

Method 2. Dissolve 0-25 g. of 2 4-dinitrophenylhydrazine in a mixture of 42 ml. of concentrated hydrochloric acid and 50 ml. of water by warming on a water bath dilute the cold solution to 250 ml. with distilled water. This reagent is more suitable for water-soluble aldehydes and ketones since alcohol is absent. 

There are four basic sulfates that can be identified by potentiometric titration using sodium carbonate (39,40) langite [1318-78-17, CuSO -3Cu(OH)2 H2 i brochantite [12068-81 -4] CuSO -3Cu(OH)2 antedite [12019-54-4] CuSO -2Cu(OH)2 and CuS0 -Cu0-2Cu(0H)2-xH20. The basic copper(II) sulfate that is available commercially is known as the tribasic copper sulfate [12068-81 ] CuS04-3Cu(0H)2, which occurs as the green monoclinic mineral brochantite. This material is essentially insoluble in water, but dissolves readily in cold dilute mineral acids, warm acetic acid, and ammonia solutions. 

A solution of 10 grams of d-glucoheptonic acid lactone in 50 ml of distilled water is warmed on a steam bath for about 2 hours to hydrolyze the lactone to the acid. The mixture is cooled and 100 ml of 95% ethanol are added. To the solution of glucoheptonic acid are added about 37 grams of erythromycin and the volume of the reaction mixture is brought to 200 ml by the addition of 95% ethanol. The reaction mixture is stirred for about 2 hours and is filtered through a porcelain filter candle of porosity 02. To provide a steriie product, aseptic technique is used throughout the remainder of the procedure. 

The Deamination of Adenosine 20 g of adenosine are dissolved in one liter of water by warming, and after cooling to room temperature 120 g of barium nitrite (monohydrate) are added to the solution. Under stirring there is added in time intervals of one hour 160 cc of 2N sulfuric acid after each time interval. After the third addition, the reaction mass is allowed to stand for 3 hours at room temperature. The solution is then tested for barium, and if some barium is still present a slight excess of sulfuric acid is added. 300 cc of methanol is then added. In order to drive off the excess of nitrous acid, CO is conducted... 

A mixture of 50 parts by weight of racemic 2-acetylamino-1 -(4-methylmercaptophenyl)-1,3-propanediol, 100 parts by weight of concentrated hydrochloric acid, and 500 parts by weight of water was warmed on a steam bath for thirty minutes. The resulting solution was cooled to about 40 C and was then made strongly alkaline by addition of 35% aqueous sodium hydroxide solution. The alkaline solution was then refrigerated. The white solid which separated from the cooled solution was collected on a filter. There was thus obtained 27 parts by weight of 2-amino-1-(4-methylmercaptophenyl)-1,3-propanediol. This product melted at 130.7°C to 131 after recrystallization from methanol. 

Forty-three grams (0.25 mole) of />-bromoaniline (Note 1) and 20 cc. of water are warmed in a 400-cc. beaker until the bromoaniline melts, and then 50 cc. of concentrated hydrochloric acid (sp. gr. 1.19) is added with mechanical stirring. The mixture is heated and stirred until solution is practically complete (Note 2). The beaker is then set in a dish of ice water and the solution is stirred as it cools in order to precipitate the />-bromoaniline hydrochloride in fine crystals. A few small pieces of ice are added and the cold (about 0-5 °) suspension is diazotized with a solution of 18 g. of sodium nitrite in 36 cc. of water to an end point with starch-iodide paper. 

The above procedure may be adapted to the determination of molybdenum in steel. Dissolve a 1.00 g sample of the steel (accurately weighed) in 5 mL of 1 1 hydrochloric acid and 15 mL of 70 per cent perchloric acid. Heat the solution until dense fumes are evolved and then for 6-7 minutes longer. Cool, add 20 mL of water, and warm to dissolve all salts. Dilute the resulting cooled solution to volume in a 1 L flask. Pipette 10.0 mL of the diluted solution into a 50 mL separatory funnel, add 3 mL of the tin(II) chloride solution, and continue as detailed above. Measure the absorbance of the extract at 465 rnn with a spectrophotometer, and compare this value with that obtained with known amounts of molybdenum. Use the calibration curve prepared with equal amounts of iron and varying quantities of molybdenum. If preferred, a mixture of 3-methylbutanol and carbon tetrachloride, which is heavier than water, can be used as extractant. 

Spray solution I For alkaloids Dissolve 1 g iodine and 10 g potassium iodide in 50 ml water with warming, add 2 ml glacial acetic acid and make up to 100 ml with water [1]. 

For sulfoxides Dissolve 5 g starch and 0.5 g sodium iodide 100 ml water with warming. Add 1 ml cone, hydrochloric acid 10 ml of the solution immediately before use [8]. 

A sample of 0.4863 gram of this purified 0,0-diethyl O-p-nitrophenyl thiophosphate was dissolved in acetone to make 1 liter of standard solution. A 20-ml. aliquot, containing 9.73 mg., was placed in a 100-ml. volumetric flask and 30 ml. of acetone were added. Then 0.35 gram of potassium chloride and 0.6 gram of acetic acid were dissolved in about 25 ml. of water and added to the acetone solution 0.01 g am of gelatin was dissolved in a few milliliters of water by warming, cooled, and added to the above, and the... 

The weaker the acid, the longer it should be heated for. Do not allow evaporation of the liquid B. inside. Do not boil. Maintain temperature below 50° C or 122° F. Since we are using pickle jars, and not pyrex, they can shatter easily if heated or cooled too quickly. It is recommended using a double boiler with hot (not boiling) water to warm the solution. To cool, simply turn off the heat source and allow the solution to slowly return to room temperature. 

In a 500-ml. three-necked flask fitted with a sealed mechanical stirrer and a reflux condenser are placed 86 g. (1 mole) of 7-butyrolactone (Note 1) and 72 g. (1.1 moles) of potassium cyanide (Note 2). As the contents of the flask are stirred, the mixture is heated in an oil bath for 2 hours at a temperature of 190-195° (Note 3). There is an initial vigorous reaction which soon subsides. After the completion of the heating period the mixture is cooled to about 100°, and the potassium salt of the cyano acid is dissolved in about 200 ml. of hot water. The warm solution is cautiously acidified to Congo Red by the addition of about 90 ml. of concentrated hydrochloric acid. The resultant solution, which contains glutaric acid monoamide and potassium chloride, is used to prepare glutaric acid or glutarimide. 

Add 2 ml of SPA nitric acid then a few ml of deionized water and warm until all solids dissolved... 

Procedure Weigh accurately about 1 g of sodium nitrite and dissolve it in DW to make 100 ml in a volumetric flask. Transfer 10 ml of this solution into a mixture of 50 ml of 0.1 N KMn04, 100 ml of water and add 5 ml of sulphuric acid along the side of the flask. Heat the contents to 40°C, allow it to stand for 5 minutes and add 25 ml of 0.1 N oxalic acid. Warm the resulting mixture to about 80°C on a steam-bath and titrate with 0.1 N KMn04 solution. Each ml of 0.1 N potassium permanganate is equivalent to 3.450 mg of NaN02. 

Procedure Moisten 1 g of carbenicillin sodium in a silica crucible with 2 ml of sulphuric acid. Heat, gently at first, then more strongly until all carbon is removed and a white ash is obtained. Allow to cool and add 5 ml of a mixture of nitric acid and hydrochloric acid and evaporate to dryness on a water-bath. Add 3 ml of hydrochloric acid, warm to dissolve and add sufficient water to produce 25 ml. 

In a i-l. beaker are placed 108 g. (1 mole) of o-phenylene-diainine (Org. Syn. 19, 70), 120 g. (115 cc., 2 moles) of glacial acetic acid, and 300 cc. of water. By warming the mixture slightly a clear solution is obtained. The beaker is placed in ice water and the contents cooled to 50. As soon as this temperature is reached, a cold solution of 75 g. (1.09 moles) of sodium nitrite... 

Heat the flask gently until frothing ceases, more strongly until the solution clears, and then for a further 1 h with the sulphuric acid condensing in the lower part of the neck of the flask. Allow to cool, carefully add approximately 100 ml of water and warm to dissolve the soluble material. When cool, transfer quantitatively into a 250-ml volumetric flask and dilute to 250 ml. Retain the diluted digest for the determination of ammonium nitrogen. 

---