Water separating mixtures

In a conventional gasoline containing hydrocarbons or even ethers, the presence of water is not a problem in fact, water is totally soluble up to about 50 ppm at ambient temperature. Beyond this value water separates without affecting the hydrocarbon phase and the water leg can be withdrawn if necessary. On the other hand, in the presence of alcohols (ethanol and especially methanol), trace amounts of water can cause a separation of two phases one is a mixture of water and alcohol, the other of hydrocarbons (Cox, 1979). 

Most characteristics of amphiphilic systems are associated with the alteration of the interfacial stnicture by the amphiphile. Addition of amphiphiles might reduce the free-energy costs by a dramatic factor (up to 10 dyn cm in the oil/water/amphiphile mixture). Adding amphiphiles to a solution or a mixture often leads to the fomiation of a microenuilsion or spatially ordered phases. In many aspects these systems can be conceived as an assembly of internal interfaces. The interfaces might separate oil and water in a ternary mixture or they might be amphiphilic bilayers in... 

In the Schotten-Baumann method of benzoylation, the hydroxyl- or amino-compound (or a salt of the latter) is dissolved or suspended in an excess of 10% aqueous sodium hydroxide solution, a small excess (about 10% more than the theoretical amount) of benzoyl chloride is then added and the mixture vigorously shaken. Benzoylation proceeds smoothly under these conditions, and the solid benzoyl compound, being insoluble in water, separates out. The sodium hydroxide then hydrolyses the excess of benzoyl chloride, giving sodium... 

Di-n-hexyl ether. Use 50 g. (61 ml.) of n-hexyl alcohol (b.p. 156-157°) and 6 g. (3-5 ml.) of concentrated sulphuric acid, and heat until the temperature rises to 180°. Pour the reaction mixture into water, separate the upper layer, wash it twice with 5 per cent, sodium hydroxide solution, then with water, and dry over anhydrous potassium carbonate. Distil from a 50 ml. Claisen flask, and collect the fractions of b.p. (i) 160-221° (17 g.), and (u) 221-223° (17 g.). Reflux fraction (i) with 4 g. of sodium and distil from the excess of sodium 9 - 5 g. of fairly prure n-hexyl ether, fraction (iii), are thus obtained. Combine fractions (ii) and (iii) and distil from a little sodium collect the pure n-hexyl ether (19 g.) at 221 - 5-223°. 

By refluxing a mixture of the acid (1 mol), alcohol (3-4 mols), dry benzene (375 ml.) and concentrated sulphuric acid (58-60 g.). The ester as formed passes into the benzene layer. Upon the addition of water, separating the benzene layer, and distilling the latter (after washing and dr3dng), benzene and alcohol pass over first, followed by the ester, for example ... 

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... 

Furfuryl acetate. Reflux a mixture of 39 2 g. (34-8 ml.) of redistilled furfuryl alcohol, 48 g. of glacial acetic acid, 150 ml. of benzene and 20 g. of Zeo-Karb 225/H in a 500 ml. bolt-head flask, using the apparatus described under iaoPropyl Lactate. After 3 hours, when the rate of collection of water in the water separator is extremely slow, allow to cool, separate the resin by suction filtration, and wash it with three 15 ml. portions of benzene. Remove the benzene, etc., from the combined filtrate and washings under reduced pressure (water pump) and then collect the crude ester at 74-90°/10 mm. a small sohd residue remains in the flask. Redistil the crude ester from a Claisen flask with fractionating side arm pure furfuryl acetate passes over at 79-80°/17 mm. The yield is 14 -5 g. 

Place 200 g, (250 ml.) of rectified spirit in a 1-litre round-bottomed flask fitted with a reflux condenser. Cool in ice and run in, slowly and with frequent shaking, 200 g. (109 ml.) of concentrated sulphuric acid. Add 83 g. (104 ml.) of -butyl cyanide (Section 111,113) to the mixture and reflux the whole for 10 hours. Allow to cool, pour the reaction mixture into ice water, separate the upper layer of ester and alcohol, and dry over anhydrous magnesium or calcium sulphate. Distil through a fractionating column and collect the ethyl n-valerate at 143-146°. A further amovmt of the pure ester may be obtained by redrying the fraction of low boiling point and redistilling. The yield is 110 g. 

Dissolve 57 g. of dry malonic acid in 92 5 ml. of dry P3rridine contained in a 500 ml. round-bottomed flask, cool the solution in ice, and add 57 g. (70 ml.) of freshly distilled n-heptaldehyde (oenanthol) with stirring or vigorous shaking. After a part of the aldehyde has been added, the mixture rapidly seta to a mass of crystals. Insert a cotton wool (or calcium chloride) tube into the mouth of the flask and allow the mixture to stand at room temperature for 60 hours with frequent shaking. Finally, warm the mixture on a water bath until the evolution of carbon dioxide ceases (about 8 hours) and then pour into an equal volume of water. Separate the oily layer and shake it with 150 ml. of 25 per cent hydrochloric acid to remove pyridine. Dissolve the product in benzene, wash with water, dry with anhydrous magnesium sulphate, and distil under reduced pressure. Collect the ap-nonenoic acid at 130-13272 mm. The yield is 62 g. 

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. 

Place 75 g. (74 ml.) of benzyl cyanide (Section IV,160), 125 g. (153 ml.) of rectifled spirit and 150 g. (68 ml.) of concentrated sulphuric acid in a 750 ml. round-bottomed flask, fitted with an efficient reflux condenser. Reflux the mixture, which soon separates into Wo layers, gently for 8 hoius, cool and pour into 350 ml. of water. Separate the upper layer. Dissolve it in about 75 ml. of ether (1) in order to facilitate the separation of the layers in the subsequent washing process. Wash the ethereal solution carefully with concentrated sodium bicarbonate solution until effervescence ceases and then with water. Dry over 10 g. of anh3 drous magnesium sulphate for at least 30 minutes. Remove the solvent with the aid of the apparatus shown in Fig. II, 13, 4 and distil from an air bath (Fig. II, 5, 3). The ethyl phenylacetate passes over at 225-229° (mainly 228°) as a colourless liquid the yield is 90 g. Alternatively, the residue after removal of the ether may be distilled in a Claisen flask under diminished pressm (Fig. II, 20, 1) collect the ester at 116-lI8°/20 mm. 

The diethyl fumarate is readily prepared as follows. Reflux a mixture of 146 g. of fumaric acid (Section 111,143), 185 g. (236 ml.) of absolute ethanol, 450 ml. of boizene and 20 g. of concentrated sulphuric acid for 12 hours. Pour into a large volume of water, separate the benzene layer, wash successively with water, saturated lodium bicarbonate solution and water, dry with anhydrous magnesium sulphate, and remove the solvent on a steam bath. Distil the residue and collect the diethyl fumarate at 213-215° the yield is 150 g. 

The purified commercial di-n-butyl d-tartrate, m.p. 22°, may be used. It may be prepared by using the procedure described under i o-propyl lactate (Section 111,102). Place a mixture of 75 g. of d-tartaric acid, 10 g. of Zeo-Karb 225/H, 110 g. (136 ml.) of redistilled n-butyl alcohol and 150 ml. of sodium-dried benzene in a 1-litre three-necked flask equipped with a mercury-sealed stirrer, a double surface condenser and an automatic water separator (see Fig. Ill, 126,1). Reflux the mixture with stirring for 10 hours about 21 ml. of water collect in the water separator. FUter off the ion-exchange resin at the pump and wash it with two 30-40 ml. portions of hot benzene. Wash the combined filtrate and washings with two 75 ml. portions of saturated sodium bicarbonate solution, followed by lOu ml. of water, and dry over anhydrous magnesium sulphate. Remove the benzene by distillation under reduced pressure (water pump) and finally distil the residue. Collect the di-n-butyl d-tartrate at 150°/1 5 mm. The yield is 90 g. 

TABLE XI,9,1. GENERAL SCHEME FOR SEPARATION OF A WATER-INSOLUBLE MIXTURE... 

The above procedure for the separation of a water-soluble mixture is summarised in Table XI,9,2. 

When the recycle soot in the feedstock is too viscous to be pumped at temperatures below 93°C, the water—carbon slurry is first contacted with naphtha carbon—naphtha agglomerates are removed from the water slurry and mixed with additional naphtha. The resultant carbon—naphtha mixture is combined with the hot gasification feedstock which may be as viscous as deasphalter pitch. The feedstock carbon—naphtha mixture is heated and flashed, and then fed to a naphtha stripper where naphtha is recovered for recycle to the carbon—water separation step. The carbon remains dispersed in the hot feedstock leaving the bottom of the naphtha stripper column and is recycled to the gasification reactor. 

Several N-substituted pyrroHdinones eg, ethyl, hydroxyethyl and cyclohexyl, are used primarily in specialized solvent appHcations where their particular physical properties are advantageous. For example, mixtures of l-cyclohexyl-2-pyrroHdinone and water exhibit two phases at temperatures above 50°C below that temperature they are miscible in aH proportions. This phenomenon can be used to facHitate some extractive separations. Mixtures of 1-alkyl-pyrroHdinones that are derived from coconut and taHow amines can be used at lower cost in certain appHcations where they may be used instead of the pure l-dodecyl-2-pyrroHdinone and l-octadecyl-2-pyrroHdinone. 

Fig. 18. Separation of ethanol from an ethanol—water—benzene mixture using benzene as the entrainer. (a) Schematic representation of the azeo-column (b) material balance lines where I denotes the homogeneous and the heterogeneous azeotropes D, the end points of the Hquid tie-line and A, the overhead vapor leaving the top of the column. The distillate regions, I, II, and III, and the boundaries are marked. Other terms are defined in text.

Fig. 19. Separation of ethanol and water from an ethanol—water—benzene mixture. Bottoms and are water, B is ethanol, (a) Kubierschky three-column sequence where columns 1, 2, and 3 represent the preconcentration, azeotropic, and entrainer recovery columns, respectively, (b) Material balance lines from the azeotropic and the entrainer recovery columns, A and E, respectively, where represents the overall vapor composition from the azeo-column, 2 1SP Hquid in equiUbrium with overhead vapor composition from the azeo-column, Xj, distillate composition from entrainer...

Carbon Dioxide—Water-Vapor Mixtures When these gases are present together, the total radiation due to both is somewhat less than the sum of the separately calculated effects, because each gas is somewhat opaque to radiation from the other in the wavelength regions 2.7 and 15 [Lm. 

After the addition of 2 1. of water, the mixture is steam-distilled as long as any oil comes over. The crude, heavy, yellow oil is separated and washed with two 200-cc. portions of 10 per cent sodium hydroxide, once with 100 cc. of water, twice with 150-cc. portions of concentrated sulfuric acid, and finally with 100 cc. of 5 per cent, sodium carbonate solution. It is dried with about 5 g. of calcium chloride, filtered through glass wool, and distilled using a long air condenser. Most of the product boils at i8o-i83°/75o mm. The yield of pure colorless material, b.p. i83°/76o mm., is 125-135 g. (36-39 per cent of the theoretical amount, based on the amount of -toluidine originally used, or 54-59 per cent based on the amount of 3-bromo-4-amino-toluene). 

A. 0-Methyl-ls -2-octalone id,lA-Dimethylhydra2one. A 250-ml., round-bottomed flask equipped with a magnetic stirring bar and a Dean-Stark water separator is maintained under a dry nitrogen atmosphere (Note 1) and eharged with 7.4 g. (0.045 mole) of 10-methyl-A -2-oetalone [2(3 f)-Naphthalenone, 4,4a,5,6,7,8-hexahydro-4a-methyl-] (Note 2), 9.0 g. (0.15 mole) of N,N-dimethylhydrazine, 150 ml. of dry benzene, and 0.02 g. of p-toluenesulfonie aeid. This mixture is refluxed for 10-14 hours, after whieh time no further water separates. Benzene and excess N,A -dimethylhydrazine are then removed by simple distillation, and the residue is distilled under reduced pressure to give 8.1 g. (87%) of the dimethylhydrazone as a pale-yellow liquid, b.p. 94-98 (0.2 mm.) (Notes 3, 4). 

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