Ethyl Alcohol-Water Mixtures

CH3)3COH) at 293 K]. With increase in temperature, the extrema in 8mnt curves at low mole fractions become almost lost (e.g. ethane in water + ethyl alcohol mixtures at 303 K). 

The effects of storing lead azide for long periods in 50 50 water-ethyl alcohol mixtures have been investigated by impact sensitivity tests. In a specific instance [43] dextrinated lead azide which had been stored for about 25 years was tested, and no significanl change in sensitivity to impact or heat was detected when compared to freshly made material. 

Figure 2 Viscosily of water/ethyl-alcohol mixtures as a function of temperature, [3].

Ethyl acetate. Various grades of ethyl acetate are marketed. The anhydrous comjjound, b.p. 76-77°, is of 99 per cent, purity, is inexpensive, and is suitable for most purposes. The 95-98 per cent, grade usually contains some water, ethyl alcohol and acetic acid, and may be ptuified in the following manner. A mixture of 1 litre of the commercial ethyl acetate, 100 ml. of acetic anhydride and 10 drops of concentrated sulphuric acid is refluxed for 4 hours and then fractionated. The distU-late is shaken with 20-30 g. of anhydrous potassium carbonate, filtered and redistilled. The final product has a purity of about 99-7% and boils at 77°/760 mm. 

Water, ethyl alcohol and carbon tetrachloride form a ternary mixture boiling at about 61 °. This vapor mixture, on condensation, separates into two phases the heavier liquid consists of carbon tetrachloride and alcohol with only small amounts of water the lighter liquid consists of approximately 65 per cent alcohol, 25 per cent water and 10 per cent carbon tetrachloride. By taking advantage of this fact, it is possible to conduct the esterification at a temperature so low that the ethyl hydrogen oxalate first formed does not decompose into ethyl formate and other products, as is the case when the customary methods of esterification are employed. 

Methyl alcohol (methanol, wood alcohol, CH3OH boiling point 64.7°C, density 0.7866, flash point 110°C) is a colorless, mobile liquid with a mild characteristic odor (and narcotic properties) that is miscible in all proportions with water, ethyl alcohol, or ether. When ignited, methyl alcohol burns in air with a pale blue, transparent flame, producing water and carbon dioxide. The vapor forms an explosive mixture with air. The upper explosive limit is 36.5% and the lower limit is 6.0% by volume in air. 

In certain cases, 8m/x° does show an extremum value. For example, 5mjU°(HI) has a maximum near x2 = 0-15 in methyl alcohol + water mixtures followed by a minimum near x2 = 0 3 where 5mpt° (HI) = 0 (Feakins, 1967) while 5m/x (HC1) in ethyl alcohol mixtures has a point of inflexion which is less marked in aqueous mixtures of isopropyl alcohol and t-butyl alcohol (Morel and Morin, 1970). Similar points of inflexion are apparent in plots of 5m against volume fraction of methyl alcohol for NaCl, NaBr, and Nal, becoming more marked in that order (Feakins and Voice, 1973). Transfer data for alkali-metal chlorides from water to three dioxan + water mixtures show that 5m (MCI) increases with increase in cation size and w2% (Feakins et al., 1975). A similar trend is observed for 5mjue (NaCl) when THF is added (Treiner, 1973). 

The Step 1 product (54.5 g) was treated with cyanoacetic acid dissolved in 260 ml acetic anhydride, then heated 2 hours to 80°C, and concentrated. The residual oil was dried by evaporation three times with 400 ml water/ethyl alcohol, 1 9, then dissolved in a mixture of 600 ml ethyl alcohol and 300 ml water at 80°C. The solution pH was raised to 10 using 10% aqueous NaHCOs, then diluted with 75 ml water, and colorless crystals isolated. The crystals were washed three times with 500 ml, dried, and the product isolated in 94% yield, mp = 138—141 °C. 

The Step 1 product was stirred at 125°C in n-butyl acetate with /t-toluenesulfonic acid, then cooled, filtered, and washed with water. The mixture was then treated with water, ethyl alcohol, chlorotris(triphenylphosphine)rhodium, degassed, and heated for 3-5 hours at 75°C. The racemic acid was extracted with 2M NaOH, then washed with butyl acetate. It was then treated with methyl alcohol followed by the slow addition of 2 M HC1 and the product isolated by filtration. The material was used directly without further purification. 

A mixture consisting of the Step 2 product (57 g), 1150 ml acetone, KSCN (36.6 g), and 43.8 ml benzoyl chloride was refluxed 3 hours, then poured onto 2.4 kg crushed ice. The precipitate was isolated, then treated with KOH (85 g), 85 ml of water, and 255 ml ethyl alcohol, then heated 2 hours at 60°C. The mixture was cooled, then diluted with 850 ml of water, ethyl alcohol distilled off, and 72 g of product isolated. 

The product from Step 4 (0.130 mol), 205 ml of isopropyl alcohol and potassium t-butylate (0.156 mol) were mixed, transferred into a 380 ml stirred stainless steel autoclave, and 4.0 ml of the prepared ruthenium asymmetric catalyst solution added. The mixture was hydrogenated at ambient temperature at 4 x 10 Pa 3 hours. Thereafter, the mixture was filtered, concentrated, and the residue dissolved in a water/ethyl acetate mixture. It was treated with a 5% NH4CI solution and the organic phase dried. HPLC analysis of an aliquot indicated that the cis/trans product ratio was 99 1, respectively, with an enantiomeric excess of (S,S)-cis-l,4-dibenzyl-piperidin-3-ol of 91%. 

Figure 23.12 depicts the change of XPS peaks as a consequence of water immersion. When similar experiments were carried out with a mixture of water/ethyl alcohol (50 50 volume ratio), the conspicuous appearance and increase with time were not observed as shown in Figure 23.13. The increase of O Is peak as function of water immersion time is depicted in Figure 23.14, which includes immersion in a dilute solution of a surfactant and 50 50 mixture of water and ethanol. The reason why the increase of O Is is influenced by the water mixtures is related to the driving force responsible for such changes. This aspect is discussed in Chapter 25.

Sometimes the equilibrium is shifted by removing one of the products. An elegant way of doing this is illustrated by the preparation of ethyl adipate. The dicarboxylic acid adipic acid, an excess of ethyl alcohol, and toluene arc heated with a little sulfuric acid under a distillation column. The lowest boiling component (b.p. 75 ) of the reaction mixture is an azeotrope of water, ethyl alcohol, and toluene fcomoare Sec. 15.6) consequently, as fast as water is formed it is... 

Fractional" distillation is used to separate mixtures of two liquids with different boiling points, such as alcohol and water. Ethyl alcohol with 4 percent water boils at approximately 173° F, while water boils at 212° F. A mixture of the two liquids will boil at all temperatures between 173° and 212°, depending on the ratio of alcohol... 

Solubility in Water and in Aqueous Ethyl Alcohol Mixtures... 

Ethyl Alcohol and Water.—Ethyl alcohol containing, say, 16 or 20 per cent, of water would behave in the manner indicated by the same curve (Fig. 65), but, in this case, even svith the most efficient still-head, we should not have pure alcohol in the first part of the distillate, nor even the pure mixture of constant boiling point, but a mixture containing at least 5 and probably. as much as 7 or 8 per cent, of water, for the mixture of constant boiling point which contains 95 57 per cent, of alcohol is extremely difficult to separate from water, although there is a wide difference between the two boiling points. 

Cerium oxide has been deposited from electrolytic solution containing either cerium nitrate or cerium chloride salts. Using chloride salts poses a problem, in that the deposits tend to be amorphous and incorporate chloride ions into the films except under certain conditions. Creus et al. found that to deposit using cerium chloride salts required either an addition of H2O2 to the aqueous electrol3d e solution or use of a mixed water-ethyl alcohol solution [74]. Others also found that the base generation method could be used for the deposition from chloride salts when the plating solution contained a mixture of water and ethanol [70, 75,76]. 

Chemical methods may be employed if the reagent attacks only one of the components. Thus quicklime may be employed for the removal of water in the preparation of absolute ethyl alcohol. Also aromatic and unsaturated hydrocarbons may be removed from mixtures with saturated hydrocarbons by sulphonation. 

Some liquids are practically immiscible e.g., water and mercury), whilst others e.g., water and ethyl alcohol or acetone) mix with one another in all proportions. Many examples are known, however, in which the liquids are partially miscible with one another. If, for example, water be added to ether or if ether be added to water and the mixture shaken, solution will take place up to a certain point beyond this point further addition of water on the one hand, or of ether on the other, will result in the formation of two liquid layers, one consisting of a saturated solution of water in ether and the other a saturated solution of ether in water. Two such mutually saturated solutions in equilibrium at a particular temperature are called conjugate solutions. It must be mentioned that there is no essential theoretical difference between liquids of partial and complete miscibility for, as wdll be shown below, the one may pass into the other with change of experimental conditions, such as temperature and, less frequently, of pressure. 

For ethyl alcohol, two volumes of dicycZohexyl are mixed with one volume of the alcohol, a thermometer is introduced, and the mixture heated until it becomes clear. The solution is then slowly cooled, with constant stirring, and the temperature is determined at which the opalescent solution suddenly becomes turbid so that the immersed portion of the mercury thread of the thermometer is no longer clearly visible. This is the C.S.T. The water content may then be evaluated by reference to the following table. 

The use of a ternary mixture in the drying of a liquid (ethyl alcohol) has been described in Section 1,5 the following is an example of its application to the drying of a solid. Laevulose (fructose) is dissolved in warm absolute ethyl alcohol, benzene is added, and the mixture is fractionated. A ternary mixture, alcohol-benzene-water, b.p. 64°, distils first, and then the binary mixture, benzene-alcohol, b.p. 68-3°. The residual, dry alcoholic solution is partially distilled and the concentrated solution is allowed to crystallise the anhydrous sugar separates. 

Absolute ethyl alcohol. Ethyl alcohol of a high degree of purity is frequently required in preparative organic chemistry. For some purposes alcohol of ca. 99 -5 per cent, purity is satisfactory this grade may be purchased (the absolute alcohol of commerce), or it may be conveniently prepared by the dehydration of rectified spirit with quicklime. Rectified spirit is the constant boiling point mixture which ethyl alcohol forms with water, and usually contains 95 6 per cent, of alcohol by weight. Wherever the term rectified spirit is used in this book, approximately 95 per cent, ethyl alcohol is to be understood. 

One litre of commercial absolute alcohol (or any ethyl alcohol of 99 per cent, purity or better) is treated with 14 g. of clean, dry sodium when the sodium has completely reacted, 40 g. of pure ethyl formate are added. The mixture is refluxed for 2-3 hom , and the dry alcohol is distilled oflF as in Method 2 the first 25 ml. of distillate are discarded. The super-dry alcohol contains about 0 03 per cent, of water. 

Other mixtures which may be employed are carbon tetrachloride (b.p. 77°) and toluene (b.p. 110-111°) chloroform (b.p. 61°) and toluene methyl alcohol (b.p. 65°) and water (b.p. 100°). The last example is of interest because almost pure methyl alcohol may be isolated no constant boiling point mixture (or azeotropic mixture) is formed (compare ethyl alcohol and water, Sections 1,4 and 1,5). Attention is directed to the poisonous character of methyl alcohol the vapour should therefore not be inhaled. 

Place a mixture of 114 g. (140 ml.) of methyl -amyl ketone (2-hepta-none) (1), 300 ml. of rectified spirit (95 per cent, ethyl alcohol) and 100 ml. of water (2) in a 1500 ml. three-necked fiask or in a 1500 ml. round-bottomed fiask provided with a two-way addition tube (Fig. 11,13, 9). Attach an efficient double surface condenser to the fiask and close the... 

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