Ethyl alcohol, washing with

The wet gluten (about 1300 g. ) is placed (Note 3) in a 5-I. round-bottom flask and covered with 1600 cc. of concentrated hydrochloric acid (sp. gr. 1.19). This reaction mixture is then warmed on the steam bath until the purple color disappears (about two hours). A reflux condenser is then attached and the solution is boiled gently over a flame for about eighteen hours. The hot solution is filtered with suction (Note 4) and the black residue of melanin is washed with about 200 cc. of water. The combined filtrate and washings are concentrated under reduced pressure until the volume is reduced to about 1500 cc. This solution is allowed to cool to room temperature and the crystals of glutamic acid hydrochloride filtered and washed with two 30-cc. portions of 95 per cent ethyl alcohol saturated with hydrogen chloride. The washings are discarded (Note 5) and the... 

The crystal mass is then separated from the mother liquor by careful decantation or by filtration through a Buchner funnel. In either case, the product is carefully washed several times with cold distilled water, f then with 95 per cent ethyl alcohol and with ether. If the crystals are washed by decantation, the yield may not exceed 75 per cent. If absolute purity is not essential, and filtration is carried out on the Buchner funnel, the yield may be considerably higher as indicated by the following experimental results. 

For purification, the product is dissolved in 800 cc. of 1 N sodium hydroxide, 500 cc. of ethyl alcohol is added, and the solution is filtered. The filtrate is transferred to a 2-1. beaker and is heated to the boiling point. Then 160 cc. of 5 A hydrochloric add is slowly added, through a dropping funnel, while stirring by hand. The mixture is cooled to room temperature and is filtered with suction. The product is washed with 100 cc. of ethyl alcohol, then with 200 cc. of water, and is dried in a vacuum desiccator over phosphorus pentoxide. The nearly white, lustrous platelets have no definite melting point (Note 5). The yield of pure amino acid is 98-112 g. (33-37 per cent of the theoretical amount) (Note 6). 

A hot solution of sodium ethoxide is prepared, in a 3-1. round-bottomed flask, from 46 g. (2 gram atoms) of sodium and 1.6 1. of absolute ethyl alcohol. With shaking, a solution of 139 g. (2 moles) of hydroxylamine hydrochloride in 100 cc. of hot water is added. The resulting suspension is cooled Quickly by placing the flask in an ice-water mixture and is then filtered with suction through a Buchner funnel. The residue of sodium chloride is washed with small portions (total 200 cc.) of absolute ethyl alcohol. The filtrate is returned to the 3-1. flask, and to it is added 148 g. (1 mole) of cinnamic acid, whereupon a voluminous precipitate forms. The mixture is refluxed on a steam bath for nine hours (Note 1). The amino acid begins to separate after five to six hours the suspended solid causes the mixture to bump (Note 2). The suspension is allowed to remain overnight at room temperature, and the crystals are then collected on a Buchner funnel (Note 3). The product is washed with 300 cc. of absolute ethyl alcohol, then with some ice-cold water to remove all the sodium chloride, and finally with 300 cc. of absolute ethyl alcohol, always in small portions. The colorless crystals of amino acid are dried in a vacuum desiccator over flake sodium hydroxide. The yield is 56 g. (34 per cent of the theoretical amount). 

A solution containing butylamidine hydrochloride (37.9 g) and K2CO3 (8.4 g) dissolved in 1,4-dioxane were to refluxed and the product from Step 2 (3.7 g) dissolved in 1,4-dioxane added. The mixture refluxed 2 hours, cooled to ambient temperature, extracted with EtOAc, washed with water, brine, dried, and concentrated. The crude product was dissolved in toluene and extracted with 10% aqueous NaOH. The solution was acidified to pH 5.0 with 10% HCl and extracted with EtOAc. The solution was concentrated, acidified using ethyl alcohol saturated with hydrochloric acid, and the solvent removed in vacuo. The residue was recrystallized from ethyl alcohol/diethyl ether and 3.1 g product isolated. H-NMR and MS data supplied. 

Immediately on adding the catalyst the reaction mixture turns red and ebullition and effervescence begin. Red crystals form gradually on the bottom of the flask. Occasional swirling helps to keep the reactants well mixed. After about 45 minutes a heavy deposit of red crystals will have formed very little liquid will be present. The crystals are collected in a Buchner funnel using mild suction, and are washed with three 25-ml. portions of ice-cold water to remove the aluminum chloride and then with three 25-ml. portions of ethyl alcohol to remove unreacted carbon tetrachloride and ethyl iodide. Washing with water causes the crystals to darken, but subsequent treatment with the alcohol restores the product to its natural bright red color. 

The developer is generally a solvent in which the components of the mixture are not too soluble and is usually a solvent of low molecular weight. The adsorbent is selected so that the solvent is adsorbed somewhat but not too strongly if the solvent is adsorbed to some extent, it helps to ensure that the components of the mixture to be adsorbed will not be too firmly bound. Usually an adsorbate adheres to any one adsorbent more firmly in a less polar solvent, consequently when, as frequently occurs, a single dense adsorption zone is obtained with light petroleum and develops only slowly when washed with this solvent, the development may be accelerated by passing to a more polar solvent. Numerous adsorbat are broken up by methyl alcohol, ethyl alcohol or acetone. It is not generally necessary to employ the pure alcohol the addition from 0 5 to 2 per cent, to the solvent actually used suffices in most cases. 

Pure pyridine may be prepared from technical coal-tar pyridine in the following manner. The technical pyridine is first dried over solid sodium hydroxide, distilled through an efficient fractionating column, and the fraction, b.p. 114 116° collected. Four hundred ml. of the redistilled p)rridine are added to a reagent prepared by dissolving 340 g. of anhydrous zinc chloride in a mixture of 210 ml. of concentrated hydrochloric acid and 1 litre of absolute ethyl alcohol. A crystalline precipitate of an addition compound (probable composition 2C5H5N,ZnCl2,HCl ) separates and some heat is evolved. When cold, this is collected by suction filtration and washed with a little absolute ethyl alcohol. The yield is about 680 g. It is recrystaUised from absolute ethyl alcohol to a constant m.p. (151-8°). The base is liberated by the addition of excess of concentrated... 

Sodamide should never be stored in a stoppered bottle from which samples are to be removed intermittently, since dangerous mixtures may result when the substance is exposed for 2-3 days to even limited amounts of air at the ordinary temperature. As a safe practice, sodamide should be used immediately after preparation, and should not be kept longer than 12-24 hours unless it be under an inert solvent. Even small amounts of unused sodamide should be removed from the apparatus in which it was made by washing with methyl or ethyl alcohol. In all cases where a yellowish or brownish colour develops, due to the formation of oxidation... 

The silver nitrite may be prepared as described in Section 11,50, 17. The product supplied by Johnson, Matthey and Co. Ltd., of Hatton Garden, London, E.C. 1, is satisfactory it. should be washed with absolute methyl or ethyl alcohol, followed by sodium-dried ether, and dried in an electrically-heated oven at 100 for 30 minutes (longer heating results in darkening on the surface) the substance should be kept in a vacuum desiccator until required. 

Mix 50 ml. of formalin, containing about 37 per cent, of formaldehyde, with 40 ml. of concentrated ammonia solution (sp. gr. 0- 88) in a 200 ml. round-bottomed flask. Insert a two-holed cork or rubber stopper carrying a capillary tube drawn out at the lower end (as for vacuum distillation) and reaching almost to the bottom of the flask, and also a short outlet tube connected through a filter flask to a water pump. Evaporate the contents of the flask as far as possible on a water bath under reduced pressure. Add a further 40 ml. of concentrated ammonia solution and repeat the evaporation. Attach a reflux condenser to the flask, add sufficient absolute ethyl alcohol (about 100 ml.) in small portions to dissolve most of the residue, heat under reflux for a few minutes and filter the hot alcoholic extract, preferably through a hot water fuimel (all flames in the vicinity must be extinguished). When cold, filter the hexamine, wash it with a little absolute alcohol, and dry in the air. The yield is 10 g. Treat the filtrate with an equal volume of dry ether and cool in ice. A fiulher 2 g. of hexamine is obtained. 

Place 50 g. of anhydrous calcium chloride and 260 g. (323 ml.) of rectified spirit (95 per cent, ethyl alcohol) in a 1-litre narrow neck bottle, and cool the mixture to 8° or below by immersion in ice water. Introduce slowly 125 g. (155 ml.) of freshly distilled acetaldehyde, b.p. 20-22° (Section 111,65) down the sides of the bottle so that it forms a layer on the alcoholic solution. Close the bottle with a tightly fitting cork and shake vigorously for 3-4 minutes a considerable rise in temperature occurs so that the stopper must be held well down to prevent the volatilisation of the acetaldehyde. Allow the stoppered bottle to stand for 24-30 hours with intermittent shaking. (After 1-2 hours the mixture separates into two layers.) Separate the upper layer ca. 320 g.) and wash it three times with 80 ml. portions of water. Dry for several hours over 6 g. of anhydrous potassium carbonate and fractionate with an efficient column (compare Section 11,17). Collect the fraction, b.p. 101-104°, as pure acetal. The yield is 200 g. 

Ethyl formate. Reflux a mixture of 61 g. (50 ml.) of A.R. formic acid (98/100 per cent.) and 31 g. (39-5 ml.) of absolute ethyl alcohol for 24 hours. Transfer to a Claisen flask with fractionating side arm (or attach a fractionating column to the flask), distil and collect the liquid passing over below 62°. Wash the distillate with saturated sodium bicarbonate solution and saturate with salt before removing the ester layer. Dry with anhydrous sodium or magnesium sulphate, filter, and distil. The ethyl formate passes over at 53-54°. The yield is 36 g. 

Place 100 g. of adipic acid in a 750 ml. round-bottomed flask and add successively 100 g. (127 ml.) of absolute ethyl alcohol, 250 ml. of sodium-dried benzene and 40 g. (22 ml.) of concentrated sulphuric acid (the last-named cautiously and with gentle swirling of the contents of the flask). Attach a reflux condenser and reflux the mixture gently for 5-6 hours. Pour the reaction mixture into excess of water (2-3 volumes), separate the benzene layer (1), wash it with saturated sodium bicarbonate solution until eflfervescence ceases, then with water, and dry with anhydrous magnesium or calcium sulphate. Remove most of the benzene by distillation under normal pressure until the temperature rises to 100° using the apparatus of Fig. II, 13, 4 but substituting a 250 ml. Claisen flask for the distilling flask then distil under reduced pressure and collect the ethyl adipate at 134-135°/17 mm. The yield is 130 g. 

Drop 1 g. of sodium into 10 ml. of ethyl alcohol in a small flask provided with a small water condenser heat the mixture until all the sodium has dissolved. Cool, and add 1 g. of the ester and 0-5 ml. of water. Frequently the sodium salt of the acid will be deposited either at once or after boiling for a few minutes. If this occurs, filter oflF the solid at once, wash it with a little absolute ethyl alcohol (or absolute methylated spirit), and convert it into the p-bromophenacyl ester, p-nitro-benzyl ester or S-benzyl-tso-thiuronium salt (for experimental details, see Section 111,85). If no solid separates, continue the boiling for 30-60 minutes, boil oflF the alcohol, allow to cool, render the product just neutral to phenolphthalein with dilute sulphuric or hydrochloric acid, convert the sodium salt present in solution into a crystalline derivative (Section 111,85), and determine its melting point. 

The acetamide often contains a minute amount of impurity having an odour resembling mice excrement this can be removed by washing with a small volume of a 10 per cent, solution of ethyl alcohol in ether or by recrystallLsation. Dissolve 5 g. of impure acetamide in a mixture of 5 ml. of benzene and 1 5 ml. of dry ethyl acetate warm on a water bath until all is dissolved and cool rapidly in ice or cold water. Filter oflF the crystals, press between Alter paper and dry in a desiccator. The unpleasant odour is absent and the pure acetamide melts at 81°. Beautiful large crystals may be obtained by dissolving the acetamide (5 g.) in warm methyl alcohol (4 ml.), adding ether (40 ml.) and allowing to stand. 

Into a 500 ml. round-bottomed flask, fitted with a reflux condenser, place 42 g. of potassium hydroxide pellets and 120 g. (152 ml.) of absolute ethyl alcohol. Heat under reflux for 1 hour. Allow to cool and decant the liquid from the residual solid into another dry 500 ml. flask add 57 g. (45 ml.) of A.R. carbon dtsulphide slowly and with constant shaking. Filter the resulting almost solid mass, after cooling in ice, on a sintered glass funnel at the pump, and wash it with two 25 ml. portions of ether (sp. gr. 0-720), followed by 25 ml. of anhydrous ether. Dry the potassium ethyl xanthate in a vacuum desiccator over silica gel. The yield is 74 g. If desired, it ma be recrystallised from absolute ethyl alcohol, but this is usually unneceasary. 

Place 32 g. of potassium ethyl xanthate (Section 111,166) and 50 ml. of absolute ethyl alcohol in a 500 ml. round-bottomed flask provided with a double surface condenser. Add 32 g. (16-5 ml.) of ethyl iodide. No reaction appears to take place in the cold. Heat on a water bath for 3 hours a reaction sets in within 15 minutes and the yellow reaction mixture becomes white owing to the separation of potassium iodide. Add about 150 ml. of water, separate the lower layer, and wash it with water. Dry it with anhydrous calcium chloride or anhydrous calcium sulphate and distil from a 50 ml. Claisen flask. Collect the ethyl S-ethyl xanthate at 196-198°. The yield is 23 g. 

Picrates are usually prepared by mixing solutions of equivalent quantities of the two components in the minimum volume of rectified spirit and allowing to cool the derivative separates in a crystalline condition. It is filtered off, washed with a little ether, and pressed on a porous tUe. If the picrate is stable, it is recrystaUised from alcohol, ethyl acetate or ether. 

The foUowing are typical experimental details for the preparation of naphthalene picrate. Dissolve 0 -1 g. of naphthalene and 0-2 g. of picric acid separately in the minimum volume of hot rectified spirit (about 2 ml.), mix the solutions and allow to cool. FUter and wash with 2 ml. of alcohol. RecrystaUise from hot alcohol, ethyl acetate or ether. 

Dissolve 3-5 g. of aniline hydrochloride in 20 ml. of absolute ethyl alcohol contained in a 50 ml. conical flask, and add 0-5 ml. of a saturate solution of hydrogen chloride in absolute ethyl alcohol. Cool in ice and add 4 g. (4 -6 ml.) of iso-amyl nitrite (compare Section 111,53) gradually. Allow the mixture to stand for 5-10 minutes at the room temperature, and precipitate the diazonium salt by the gradual addition of ether. Filter ofiF the crystals at the pump on a small Buchner funnel, wash it with 5 ml. of alcohol - ether (1 1), and then with 10 ml. of ether. Keep... 

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