Hquid water

Cooling is routinely appHed, either with ambient process water if THF is the solvent or with chilled brine if diethyl ether is used. Since Grignard reagents are particularly reactive with water, Hquid hydrocarbon coolants may be preferred, to eliminate the risk that could arise from a cooling-system leak. 

Wilson MA, Pohorille A (1997) Adsorption and solvation of ethanol at the water hquid-vapor interface a molecular dynamics study. J Phys Chem B 101 3130-3135 Wilson MA, Pohorille A, Pratt LR (1987) Molecular dynamics of the water hquid-vapor interface. 

Salt water Liquid Water (hquid) Sodium chloride (solid)... 

The problems already mentioned at the solvent/vacuum boundary, which always exists regardless of the size of the box of water molecules, led to the definition of so-called periodic boundaries. They can be compared with the unit cell definition of a crystalline system. The unit cell also forms an "endless system without boundaries" when repeated in the three directions of space. Unfortunately, when simulating hquids the situation is not as simple as for a regular crystal, because molecules can diffuse and are in principle able to leave the unit cell. 

Place a mixture of 53 g. of A.R. lactic acid (85-88 per cent, acid), 75 g. (85-5 ml.) of commercial anhydrous isopropyl alcohol, 300 ml. of benzene and 20 g. of Zeo-Karb 225/H (1) in a 700 ml. bolt-head flask, equipped with an automatic water separator (e.g., a large modified Dean and Stark apparatus with a stopcock at the lower end, see Fig. Ill, 126, 1) carrying an efficient reflux condenser at its upper end, and a mercury-sealed stirrer (alternatively, the hquid-sealed stirrer shown in Fig. 11,7,11, c. may be used). Reflux the mixture, with stirring, on a steam bath for 5 hours or until water no longer collects in appreciable amount in the water separator run off the water from time to time. Filter off the resin at the pump and wash it with two 25 ml. portions of benzene. Shake the combined filtrate and washings with about 5 g. of precipit-ated calcium... 

Transfer the reaction product to a 500 ml. Claisen flask and distil over a wire gauze or from an air bath. Some acetyl chloride and acetic acid passes over first, the temperature then rises, and the fraction, b.p. 150-200°, is collected separately run out the water from the condenser when the temperature reaches 150°. The fraction, b.p. 150-200°, solidifies on cooling. Drain off any hquid from the crystals as rapidly as possible, and redistil the solid using an air condenser. CoUect the fraction b.p. 182-192° this sets to a sohd mass on cooling and melts at 63°. The yield of monochloroacetic acid is 150-175 g. 

Nitro compounds, when hquid, have characteristic odours, are insoluble in water, highly refractive and with a density greater than unity. Many are crystalline sohds. Most nitro compounds are slightly coloured, generally yellow the intensity of the colour increases with the number of nitro groups. The following reactions will assist in their detection. 

Method 2. Transfer the dark-coloured reaction product to a separatory funnel and shake successively with water, with sufficient 5-10 per cent, sodium hydroxide solution to ensure that the washings are alkaline to litmus, and finally with water. Dry with anhydrous magnesium sulphate or calcium chloride. Filter through a fluted filter paper into a small distilling flask and distil slowly. Collect the crude bromobenzene at 150-170° pour the residue whilst still hot into a small porcelain basin. Redistil the hquid of b.p. 150-170° (3) and collect the bromobenzene at 154-157° the yield is about 60 g. 

Procedure 2. Follow Procedure 1 except that no solvent is employed. Pour the s3Tupy reaction mixture on to crushed ice, remove the resulting aryl sulphonyl chloride and/or sulphone, if a sohd, by filtration with suction and, if a hquid, by means of a small separatory funnel or dropper, and wash with water. 

Heat a mixture of 15 g. of p-nitroacetanilide and 75 ml. of 70 per cent, sulphuric acid (1) under a reflux water condenser for 20-30 minutes or until a test sample remains clear upon dilution with 2-3 times its volume of water. The p-nitroaniline is now present in the hquid as the sulphate. Pour the clear hot solution into 500 ml. of cold water and precipitate the p-nitroanihne by adding excess of 10 per cent, sodium hydroxide solution or of concentrated ammonia solution. When cold (cool the mixture in ice water, if necessary), filter the yellow crystalline precipitate at the pump, wash it well with water, and drain thoroughly. Recrystallise it from a mixture of equal volumes of rectified (or methylated) spirit and water or from hot water. Filter, wash and dry. The yield of p-nitroanihne, m.p, 148°, is 11 g. 

Hydrolysis of p-tolunitrile to p-toluic acid. Boil a mixture of 5 g. of p-tolunitrile, 80 ml. of 10 per cent, aqueous sodium hydroxide solution and 15 ml. of alcohol under a reflux condenser. (The alcohol is added to prevent the nitrile, which volatUises in the steam, from crystalhsing in the condenser it also increases the speed of hydrolysis. The alcohol may be omitted in the hydrolysis of nitriles which are hquid at the ordinary temperature, e.g., benzo-nitrUe.) The solution becomes clear after heating for about 1 hour, but continue the boiling for a total period of 1 - 5 hours to ensure complete hydrolysis. Detach the condenser and boil the solution for a few minutes in the open flask to remove dissolved ammonia and incidentally some of the alcohol CAUTION /). Cool, and add concentrated hydrochloric acid until precipitation of the p-toluic acid is complete. When cold, filter off the p-toluic acid with suction and wash with a little cold water. Recrystallise from a mixture of equal volumes of water and alcohol (methylated spirit) or from benzene. The yield of p-toluic acid, m.p. 178°, is 5-5 g. 

An alternative procedure, more suitable for the preparation of somewhat larger quantities of the bromo derivative, is the following. Dissolve 10 g, of the compovmd in 10-15 ml. of glacial acetic acid, cautiously add 3-4 ml. of hquid bromine, and allow the mixture to stand for 15-20 minutes. Pour into 50-100 ml. of water, filter off the bromo compound at the pump, and wash with a httle cold water. Recrystallise from dilute alcohol. 

Dissolve 0 -5 g. of the phenol in 4-5 ml. of dry p ridine, add 1 - 3 g. of 3 5-dinitrobenzoyl chloride and reflux for 25-30 minutes. Pour the cold reaction mixture into 40 ml. of ca. 2N hydrochloric acid. Decant the supernatant aqueous hquid from the precipitated sohd or oil and stir it vigorously with about 10 ml. of N sodium carbonate solution. Filter off the sohd derivative and wash it with water. RecrystaUise from alcohol, dilute alcohol, benzene - acetone or benzene - light petroleum (b.p. 60-80 ),... 

Benzanilide and similar compounds are very slowly hydrolysed by concentrated hydrochloric acid hydrolysis is quite rapid with 60-70 per cent, sulphuric acid (for experimental details, see Section IV,52). In the preliminary experiment boil 0 5-1 Og. of the compound with 10-20 ml. of dilute sulphuric acid (1 1 by volume) imder reflux for 20-30 minutes. Dilute with 10ml.of water and filteroflfanyacid which may be precipitated if the carboxyhc acid is hquid and volatile, distil it directly from the reaction mixture. Render the residue alkaline and isolate the base as above. 

Place an intimate mixture of 125 g. of powdered, anhydrous zinc chloride and 26-5 g. of acetophenonephenylhydrazone in a tall 500 ml. beaker in an oil bath at 170°. Stir the mixture vigorously by hand. After 3-4 minutes the mass becomes hquid and evolution of white fumes commences. Remove the beaker from the bath and stir the mixture for 5 minutes. Then stir in 100 g. of clean, white sand in order to prevent solidification to a hard mass. Digest the mixture for 12-16 hours on a water bath with 400 ml. of water and 12 ml. of concentrated hydrochloric acid in order to dissolve the zinc chloride. Filter off the sand and the crude 2-phenylindole, and boil the solids with 300 ml. of rectified spirit. Treat the hot mixture with a little decolourising carbon and filter through a pre-heated Buchner funnel wash the residue with 40 ml. of hot rectified spirit. Cool the combined filtrates to room temperature, filter off the 2-phenylindole and wash it three times with 10 ml. portions of cold alcohol. Dry in a vacuum desiccator over anhydrous calcium chloride. The yield of pure 2-phenylindole, m.p. 188-189°, is 16 g. 

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