Distillation with steam

The effect of superheated steam may be illustrated by reference to baizaldehyde, which boils at 178° at 760 mm. It distils with steam at 97-9° (Pj = 703-5 mm. and pg = 56-5 mm.) and the distillate contains 32-1 per cent, of benzaldehyde by weight. If one employs steam superheated to 133°, the vapour pressure of benzaldehyde (extrapolated from the boUing point - pressure curve) is 220 mm. hence pj = 540 (water), Pg = 220 (benzaldehyde), and... 

From nitriles by treatment with anhydrous Stannous chloride dissolved in ether saturated with hydrogen chloride the resulting crystaUine aldimine stannichloride, [(RCH=NHj)2] SnCl, or (RCH=NH,HCl)2SnCl4, is hydrolysed by warm water, and the aldehyde is isolated by distillation with steam or by extraction with a solvent (Stephen reaction), for example, for R = CH3(CH2)4, i.e., n-amyl ... 

Oximes, hydrazines and semicarbazones. The hydrolysis products of these compounds, t.e., aldehydes and ketones, may be sensitive to alkali (this is particularly so for aldehydes) it is best, therefore, to conduct the hydrolysis with strong mineral acid. After hydrolysis the aldehyde or ketone may be isolated by distillation with steam, extraction with ether or, if a solid, by filtration, and then identified. The acid solution may be examined for hydroxylamine or hydrazine or semicarbazide substituted hydrazines of the aromatic series are precipitated as oils or solids upon the addition of alkali. 

The salt is dissolved in 800 cc. of water (Note 3) and transferred to a 5-I. round-bottom flask. To the solution is added with constant stirring a solution of 200 g. of lead nitrate (0.6 mole) in 400 cc. of water. Lead sulfide separates as a heavy brown precipitate which soon turns black. The mixture is then distilled with steam into a receiver containing 5-10 cc. of. i N sulfuric acid as long as any oil comes over (Note 4). About 2-3 1. of distillate is collected. The product is separated from the water and weighs 63-66 g. 

The filtrate from the crude trimyristin contains the odorous oils of the nutmeg. A further quantity of trimyristin may be obtained from it by distilling with steam and recrystallizing the non-volatile residue twice from alcohol but the amount is not commensurate with the trouble, and this operation is not advised unless the residues from at least 5000 g. of nutmegs are on hand. 

The filtrate and the washings contain in solution a small quantity of the product. This is recovered by distillation with steam. The acid distillate will consist of snow-white crystals (if it is protected from light) and a solution of the compound. The solid is removed by filtration and washed. The filtrate is made neutral with sodium carbonate and extracted with ether. Upon drying and evaporating the ethereal layer will yield mononitrothiophene contaminated with dinitrothiophene (Note 5),... 

A mixture of 66.5 g. (0.5 mole) of tetrahydroquinoline and 400 g. of trimethylene chlorobromide (Note 1) is placed in a 1-1. round-bottomed flask attached to a reflux condenser, and heated in an oil bath held at 150-160° for 20 hours (Note 2). The reaction mixture is cooled, a solution of 50 ml. of concentrated hydrochloric acid in 500 ml. of water is added, and the excess trimethylene chlorobromide is removed by distillation with steam (Note 3). The acid residue from the steam distillation is made alkaline with a 40% solution of sodium hydroxide (about 75 ml.), and the julolidine is extracted with two 150-ml. portions of ether. The ethereal solution is washed with ISO ml. of water and dried over sodium hydroxide pellets. The ether is evaporated and the residue distilled under reduced pressure. The portion that boils at 105-110°/ mm. is collected (Notes 4 and 5). The yield is 67-70 g. (77-81%). 

Distilled with steam and crystd from water or EtOH. 

The aqueous acid solution is transferred to a i-l. round-bottomed flask provided with a separatory funnel and equipped for steam distillation. A solution of 125 g. of sodium hydroxide in 250 cc. of water is added through the funnel, and the mixture is distilled with steam (Note 4). The first liter of distillate contains most of the amine, but the distillate should be collected until it is only faintly alkaline. A small residue containing di-(a-phenylethyl)-amine and neutral substances remains in the flask and may be discarded. 

If very pure amine is desired the product described above is dissolved with 1.04 parts of crystalline oxalic acid in eight parts of hot water. After clarification with Norite, the filtered solution on cooling deposits crystals of the acid oxalate. About 5 g. of the salt remains in each 100 cc. of the mother liquor most of this can be obtained by evaporation and further crystallization. The amine is liberated from the pure oxalate with potassium hydroxide, distilled with steam, and purified as described above. When a known amount of amine is desired in water solution (as for optical resolution) a weighed amount of the (anhydrous) oxalate is decomposed and the amine is distilled quantitatively with steam. 

In the sulphonation process vaporised benzene is forced through a mist of sulphuric acid at 100-120°C and the benzene sulphonic acid formed is neutralised with soda ash to produce benzene sodium sulphonate. This is fused with a 25-30% excess of caustic soda at 300-400°C. The sodium phenate obtained is treated with sulphuric acid and the phenol produced is distilled with steam (Figure 23.1). 

The organic layer is separated, evaporated on a steam bath, and the dark semicrystalline residue is distilled with steam to remove biphenyl. The contents of the steam-distillation flask are then extracted with ether (Note 3), and the ethereal layer is separated, dried over magnesium sulfate, and percolated through a short column of chromatographic alumina (Notes 4 and 5). Evaporation of the ethereal solution gives crude triphenylene which is sublimed at 175-180° and 0.1 mm. pressure. After rejection of an initial sublimate of impure biphenyl, the sublimed material forms nearly colorless crystals, m.p. 186-194° (Note 6). Yield 8-9 g. (53-59%). It may be further purified by recrystallization from a mixture of methylene chloride and pentane yielding colorless crystals, m.p. 199° (Note 7). 

Properties.—o-Nifrop/ie/ioI, sulphur-yellow needles, possessing a peculiar smell m. p. 45 " b. p. 214 distillable with steam soluble in alcohol, ether, and hot water less soluljle in cold welter. 

Seventy grams of pinylamine nitrate are treated with a solution of 10 grams of sodium nitrite in 100 c.c. of water for some time. The yellowish oil which separates is distilled with steam, and the distillate is shaken with an oxalic acid solution in order to remove basic compounds, and again distilled with steam. Pinocarveol has the following characters —... 

To prepare it artificially, 20 grams of carvone are dissolved in 200 c.c. of absolute alcohol and 24 grams of sodium are added. Towards the end of the reaction water is added, and the product is then distilled with steam. 

This ketone, of the formula Cj H O, isomeric with those above described, is found in the oils of thuja, tansy, wormwood, and sage. It is identical with the bodies formerly described under the names tan-acetone and salvone. It is best prepared in a state of purity from oil of wormwood. According to Semmler, 200 c.c. of the oil, 0 c.c. of a saturated solution of sodium bisulphite, 75 c.c. of water, and 300 c.c. of alcohol are well shaken at intervals during a fortnight. The crystals formed, consisting of the compound of thujone with the sodium bisulphite, are separated, washed with alcohol-ether, and pressed. On treatment with caustic soda solution, the thujone, amounting to over 40 per cent, of the oil used, separates, and can be distilled with steam. 

Sack has recently isolated a ketone from natural civet. The civet was boiled for some hours with alcoholic potash, the alcohol evaporated and the residue extracted, with ether. The residue left on evaporating the ether was distilled with steam to remove skatole, again extracted with ether, the ether evaporated and the residue dissolved in alcohol. The alcohol was evaporated, and the residual ketone purified by conversion into its semi-carbazone, from which it was regenerated. It has the formula CjjHggO, and its characters are as follows —... 

Toluene is mixed with a haloid combination of butane and boiled with addition of chloride or bromide of aluminium. Water is added to the product and it is then distilled with steam, and that portion which distils over at a temperature between 170° and 200° C. is taken and treated with fuming nitric acid and fuming sulphuric acid. The resulting product is washed with water and crystallised from alcohol. 

Wasseidampf, m, water vapor, steam, -bad, n, steam bath (Afed.) vapor bath, -destil-lation, /. distillation with steam, -entwick-ler, -erzeuger, m, (steam) boiler, -gehalt, m, steam content. 

After the furfurel has all been added and the reaction has subsided, the residue is cooled, diluted with water, made strongly alkaline and distilled until all volatile substances are removed. The distillate is then made acid with formic acid and distilled with steam as long as nonbasic substances are carried over by the steam. The residue is then made strongly basic with caustic soda and the volatile amines again distilled with steem. The distillate is then treated with strong alkali and then extracted with ether to extract the base. The extract is dried by the addition of caustic potash, the ether removed and the residual amine purified by distillation. Furfuryl dimethyl amine boils over the range 145°C to 150°C. 

The reaction product, which is a dark reddish-brown liquid, is poured or siphoned (Note 5) into 1.5 1. of water to which 50 cc. of a saturated solution of sodium bisulfite has been added (Note 6). The mixture is distilled with steam (Org. Syn. 2, 80) and the first portion of the distillate is collected separately to remove a small amount of unchanged nitrobenzene. It is necessary to collect about 12 1. of distillate in order to obtain all of the m-bromonitrobenzene. The yellow crystalline solid is filtered with suction and pressed well on the funnel to remove water and traces of nitrobenzene. The yield of crude product varies from 270-340 g. (60-75 Per cent °f the theoretical amount). It melts at 51.5-520 and boils at 117-118 79 mm. This product is satisfactory for most purposes. If a purer material is desired, the crude /w-bromonitrobenzene may be distilled under reduced pressure. The recovery on purification is about 85 per cent. Briihl recorded the b.p. as 1380/18 mm. and the m.p. as 56° for pure wz-bromonitrobenzene.1... 

In a 1-1. flask arranged for steam distillation (Note 1), 50 g (0.31 mole) of isonitrosopropioplienone (Org. Syn. 16, 44 Coll. Vol. 2,1943,363) and 500 g. of 10 per cent sulfuric acid are mixed, and the mixture is distilled with steam until about 21. of distillate is collected. During the distillation the flask is heated so that the volume of the reaction mixture is kept roughly constant. The distillation requires about six hours, and at the end of this time the liquid in the flask is dear (Note 2). 

Sometimes the distillation can be performed without the superheater if the steam, dried as completely as possible, is passed, not too rapidly, into the distilling flask, containing the dry substance, which is kept hot in the bath. Volatile substances, which tend to decompose, are occasionally distilled with steam under reduced pressure and consequently at reduced temperature. 

A mixture of acetamide (30 g. = 0-5 mole) and bromine (80 g. = 26 c.c.) in a half-litre flask is kept well cooled with water while enough of a solution of 50 g. of potassium hydroxide in 350 c.c. of water is added to change the initially red-brown colour into a pale yellow this requires most of the alkali. The solution is now run from a dropping funnel in an unbroken jet into a solution of 80 g. of potassium hydroxide in 150 c.c. of water, maintained at 70°-75° in a litre flask. The operation lasts for several minutes. Until the reaction mixture becomes colourless (one quarter to half an hour) the temperature is maintained at 70°-75°, and then the methylamine is distilled with steam. An adapter is fixed to the lower end of the condenser and dips 1 cm. below the surface of the liquid in the receiver (100 c.c. of approximately 5 N-hydrochloric acid2). As soon as the liquid which forms in the condenser is no longer alkaline the distillation is discontinued and the contents of the receiver are evaporated to dryness in a porcelain basin on the water bath. The last traces of water are removed by allowing the basin to stand over night in a vacuum desiccator. The dried material is boiled with absolute alcohol, which dissolves the methylamine hydrochloride but not the ammonium chloride with which it is mixed. The clear filtrate obtained when the ammonium chloride is removed by filtration is concentrated to a small volume and the methylamine hydrochloride is allowed to crystallise out in the cold. The salt is filtered with suction, washed with a little alcohol, and dried in a desiccator. Yield 15-20 g. 

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