Glacials

Be40(02CCH3)e. The acetate is typical of the basic beryllium carboxylates (Be(OH)2 plus ethanoic acid). The structures have O at the centre of a tetrahedron of Be with carb-oxylate spanning each edge of the tetrahedron. Be(02CCH3)2 is formed from BeCl2 and glacial ethanoic acid. 

The mixture of xylidines has been used as a first component of azo-dyes. The chief constituent of the mixture is m-xylidine (4-amino-1,3-xylene). It can be separated by crystallization from glacial ethanoic acid. It is also used for the preparation of azo-dyes. 

D) Spraying solution. A solution of 0-2 g. of ninhydrin in a mixture of 99 ml. of redistilled n-butanol and i ml. of glacial acetic acid. 

To prepare pure acetic acid (glacial acetic acid), the crude aqueous product is converted into the sodium salt, the latter dehydrated by fusionf and then heated with concentrated sulphuric acid anhydrous acetic acid, b.p. 118°, distils over. Only the preparation of aqueous acetic acid and of crystalline copper acetate is described below. 

Use the apparatus shown in Fig. 38, p. 63, using a thermometer reading to 100° and with water running through the vertical condenser. Place in the 25 ml. pear-shaped flask 5 ml. of ethanol, 5 ml. of glacial acetic acid and add carefully with shying i ml. of concentrated sulphuric acid. Attach the flask to the reflux condenser and boil the mixture gently for 10 minutes. 

If a primary or secondary amine is heated with glacial acetic acid, the... 

Add 20 ml. of a mixture of equal volumes of acetic anhydride and glacial acetic acid to 10 ml. (10 3 g.) of aniline contained in a 150 ml. conical flask. Fit a reflux water-condenser to the flask, and boil the mixture gently for 10 minutes. Then pour the hot liquid into 200 ml. of cold water, stirring the latter well... 

Add 15 g. of finely powdered ammonium carbonate gradually to 50 ml. of glacial acetic acid contained in a 150 ml. round-bottomed flask, shaking the mixture during the addition to ensure a steady evolution of carbon dioxide. When all the carbonate has... 

Dissolve I g. of glucose (or fructose) in 5 ml. of water in a boiling-tube. In another tube dissolve 2 ml. of glacial acetic acid in 5 ml. of water, add 2 ml. of phenylhydrazine, and shake until... 

Dissolve 1 g. of powdered benzophenone in 6-7 ml. of cold isopropanol with shaking, add 1 drop of glacial acetic acid, and then confine the solution either in a glass receiver having a ground-glass stopper, or in a tube which is sealed... 

Dissolve I g. of finely powdered acetanilide in 5 ml. of cold glacial acetic acid contained in a 25 ml. conical flask. Then in another small flask prepare a solution of 0 42 ml. (1 34 g.) of bromine (care ) in 6 ml. of glacial acetic acid, and add this solution slowly to the acetanilide solution, shaking the latter throughout the addition to ensure thorough mixing. Allow the final mixture to stand at room temperature for 15 minutes. Then... 

For class work it is convenient to make up a single bromine solution by dissolving 7 ml. of bromine in 100 ml. of glacial acetic acid, and using 6-5 ml. of this solution for each preparation. 

Add 4 g. of aniline hydrochloride to 16 ml. of aniline contained in a 100 ml. conical flask, and then add 8 g. of diazoaminobenzene, both the solid components being finely powdered. Place the flask in a water-bath, and heat the latter carefully so that the well-stirred mixture is kept at 40° for i hour. Then remove the flask from the water-bath and allow it to stand overnight to ensure that the conversion is complete. Then add about 20 ml. of glacial acetic acid dissolved in the same volume of water, and stir the mixture well to extract the free aniline in the form of its soluble acetate. Allow the mixture to stand (with occasional stirring) for at least 10 minutes, and then filter at the... 

Dissolve 0 3 ml. of glacial acetic acid in 2 ml. of water in a 25 ml. conical flask, and add 0 4 ml. (0 44 g.) of phenylhydrazine. Mix thoroughly to obtain a clear solution of phenylhydrazine acetate and then add 0 2 ml. (0 21 g.) of benzaldehyde. Cork the flask securely and shake the contents vigorously. A yellow crystalline mass of the hydrazone soon begins to separate. Allow to stand for 15 minutes, with occasional shaking, and then filter the solid product at the pump, wash first with very dilute acetic acid and then with water, and finally drain thoroughly. Recrystallise the material from rectified or methylated spirit, the benzaldehyde phenylhydrazone being thus obtained in fine colourless needles, m.p. 157 yield, 0 4 g. 

Dichloramine-T. Dilute 80 ml, of freshly prepared 2N sodium hypochlorite soluticMi (preparation, p. 525) with 80 ml. of w ter, and then add with stirring 5 g. of finely powdered toluene-p-sulphonamide, a clear solution being rapidly obtained. Cool in ice-water, and then add about 50 ml. of a mixture of equal volumes of glacial acetic acid and water slowly with stirring until precipitation is complete the dichloro-amide separates at first as a fine emulsion, which rapidly forms brittle colourless crystals. Filter off the latter at the pump, wash well with... 

Required. Anthracene, i g. chromium trioxide, 2 g. glacial acetic acid, 15 ml. 

Dissolve 1 g. of anthracene in 10 ml. of glacial acetic acid and place in 50 ml. bolt head flask fitted with a reflux water-condenser. Dissolve 2 g. of chromium trioxide in 2 ml. of water and add 5 ml. of glacial acetic acid. Pour this solution down the condenser, shake the contents of the flask and boil gently for 10 minutes. Cool and pour the contents of the flask into about 20 ml. of cold water. Filter off the crude anthraquinone at the pump, wash with water, drain well and dry. Yield, 1 g. Purify by re crystallisation from glacial acetic acid or by sublimation using the semi-micro sublimation apparatus (Fig. 35, p. 62, or Fig. 50, p. 70). 

Required Ethyl acetoacetate, 20 g. sodium nitrite, 5 4 g. zinc dust, 11 g. glacial acetic acid, 60 ml. 

Fit a three necked 250 ml. flask with a central rubber-sleeved or mercury-sealed stirrer, c/. Fig. 23(c), p. 45, where only two necks are shown, and with a thermometer the bulb of which reaches as near the bottom of the flask as the stirrer allows the third neck will carry at first a dropping-funnel and later a reflux condenser. Place 20 g. (19-5 ml.) of ethyl acetoacetate and 45 ml. of glacial acetic acid in the flask and by ice-water cooling adjust the temperature of the stirred mixture to 5 -7° maintain this temperature whilst adding a solution of 5 4 g. of sodium nitrite in 8 ml. of water slowly from the dropping-funnel during 15 minutes. Continue the stirring for 20-30 minutes, and then... 

When the reaction is complete, heat the stirred mixture carefully under reflux over a Bunsen burner and asbestos gauze for I hour if the mixture becomes too thick for efficient stirring, add up to 15 mL of acetic acid. Now decant the hot mixture into 500 ml. of vigorously-stirred ice-cold water wash the residual zinc thoroughly with glacial acetic acid (2 portions each of I -2 ml.), decanting the acid also into the stirred water. 

Dissolve 8 8 g. (9 0 ml.) of cyclohexanone in 50 ml. of glacial acetic acid, add 8 ml. of phenylhydrazine, and boil the solution under reflux for 5 minutes. Cool the solution, when the tetrahydrocarbazole will crystallise out. Filter at the pump, drain well, and recrystallise either from aqueous ethanol or (better) from aqueous acetic acid. The recrystallisation should be performed rapidly, for the tetrahydrocarbazole undergoes atmO" spheric oxidation in hot solutions after recrystallisation, the compound should be dried in a vacuum desiccator and not in an oven. Repeated recrystallisation should be avoided. The tetrahydrocarbazole, after thorough drying, is obtained as colourless crystals, m.p. 118° yield of recrystallised material, 11 g. 

Physical properties. All are colourless crystalline solids except formic acid, acetic acid (m.p. 18 when glacial) and lactic acid (m.p. 18°, usually a syrup). Formic acid (b.p. loo ") and acetic acid (b.p. 118 ) are the only members which are readily volatile lactic acid can be distilled only under reduced pressure. Formic and acetic acids have characteristic pungent odours cinnamic acid has a faint, pleasant and characteristic odour. 

B) Oximes. Dissolve i g. of the quinone in 5 ml. of glacial acetic acid. Dissolve i g. of hydroxylamine hydrochloride in 10 ml. of 10% aqueous sodium acetate solution and shake the mixture for 5 minutes. Cool, filter off the dioxime and recrystallise from ethanol. (M.ps., p. 549.)... 

Formation of a Quinoxaline. Heat together for 5 minutes under reflux 0 2 g. of phenanthraquinone dissolved in i ml. of glacial acetic acid and 0-2 g. of O -phenylene diamine also dissolved in i ml, of glacial acetic acid. The yellow substituted quinoxaline (p. 305) separates rapidly. Cool, filter and recrystallise from benzene m.p. 225 . 

Ester formation. Heat under very efficient reflux 1 ml. of diethyl ether, 4 ml. of glacial acetic acid and i ml. of cone. H2SO4 for ro minutes. Distil off 2 ml. of liquid. Use a few drops of this liquid for the hydroxamic add test for esters (p. 334). Use the remainder for other tests for esters (p. 354). 

Glacial Acetic Acid. Acetic acid is very hygroscopic, and its freezing-point is considerably affected by the water absorbed. Satisfactory results cannot be obtained with the apparatus shown in Fig. 79, p. 433, and a specially modified apparatus must be employed (see Nitrobenzene). 

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