A Practical Handbook on the Distillation of Alcohol from Farm Products. F. B. Wright
absolute alcohol is a colorless, mobile, very volatile liquid, having a hot, burning taste, and a pungent and somewhat agreeable odor. It is very inflammable, burning in the air with a bluish-yellow flame, evolving much heat, leaving no residue, and forming vapors of carbonic anhydride and water. Its specific gravity at 0° C (32° F.) is .8095, and at 15.5° C. (60° F.) .794; that of its vapor is 1.613. It boils at 78.4° C. (173° F.). The boiling point of its aqueous mixtures are raised in proportion to the quantity of water present. Mixtures of alcohol and water when boiled give off at first a vapor rich in alcohol, and containing but little aqueous vapor; if the ebullition be continued a point is ultimately reached when all the alcohol has been driven off and nothing but pure water remains. Thus, by repeated distillations alcohol may be obtained from its mixtures with water in an almost anhydrous state.
Absolute alcohol has a strong affinity for water. It absorbes moisture from the air rapidly, and thereby becomes gradually weaker; it should therefore be kept in tightly-stoppered bottles. When brought into contact with animal tissues, it deprives them of the water necessary for their constitution, and acts in this way as an energetic poison. Considerable heat is disengaged when alcohol and water are brought together; if, however, ice be substituted for water, heat is absorbed, owing to the immediate and rapid conversion of the ice into the liquid state. When one part of snow is mixed with two parts of alcohol, a temperature as low as 5.8° F. below zero is reached.
When alcohol and water are mixed together the resulting liquid occupies, after agitation, a less volume than the sum of the two original liquids. This contraction is greatest when the mixture is made in the proportion of 52.3 volumes of alcohol and 47.7 volumes of water, the result being, instead of 100 volumes, 96.35. A careful examination of the liquid when it is being agitated reveals a vast number of minute air-bubbles, which are discharged from every point of the mixture. This is due to the fact that gases which are held in solution by the alcohol and water separately are less soluble when the two are brought together; and the contraction described above is the natural result of the disengagement of such dissolved gases. The following table represents the contraction undergone by different mixtures of absolute alcohol and water.
TABLE II.—100 VOLUMES OF MIXTURE AT 59° F.
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Alcohol.|Contraction.||Alcohol.|Contraction.||Alcohol.|Contraction.
————+——————++————+——————++————+——————
100 | 0.00 || 65 | 3.61 || 30 | 2.72
95 | 1.18 || 60 | 3.73 || 25 | 2.24
90 | 1.94 || 55 | 3.77 || 20 | 1.72
85 | 2.47 || 50 | 3.74 || 15 | 1.20
80 | 2.87 || 45 | 3.64 || 10 | 0.72
75 | 3.19 || 40 | 3.44 || 5 | 0.31
70 | 3.44 || 35 | 3.14 || |
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Alcohol is termed "absolute" when it has been deprived of every trace of water, and when its composition is exactly expressed by its chemical formula. To obtain it in this state it must be subjected to a series of delicate operations in the laboratory, which it would be impossible to perform on an industrial scale. In commerce it is known only in a state of greater or less dilution.
Alcohol possesses the power of dissolving a large number of substances insoluble in water and acids, such as many inorganic salts, phosphorus, sulphur, iodine, resins, essential oils, fats, coloring matters, etc. It precipitates albumen, gelatine, starch, gum, and other substances from their solutions. These properties render it an invaluable agent in the hands of the chemist.
Alcohol is found in, and may be obtained from, all substances—vegetable or other—which contain sugar. As stated above, it does not exist in these in the natural state, but is the product of the decomposition by fermentation of the saccharine principle contained therein; this decomposition yields the spirit in a very dilute state, but it is readily separated from the water with which it is mixed by processes of distillation, which will subsequently be described. The amount of alcohol which may be obtained from the different unfermented substances which yield it varies considerably, depending entirely upon the quantity of sugar which they contain.
Alcohol is produced either from raw materials containing starch, as potatoes, corn, barley, etc., or raw materials containing sugar, as grapes, beets, sugar-cane, etc.
The following are some of the most important sources from which alcohol is obtained: Grapes, apricots, cherries, peaches, currents, gooseberries, raspberries, strawberries, figs, plums, bananas, and many tropical fruits, artichokes, potatoes, carrots, turnips, beet-root, sweet corn, rice and other grains. Sugar-cane refuse, sorgum, molasses, wood, paper, and by a new French process from acetylene. On a large scale alcohol is usually obtained from sugar beets, molasses or the starch contained in potatoes, corn and other grains. The starch is converted into maltose by mixing with an infusion of malt. The maltose is then fermented by yeast. Sulphuric acid may be used to convert even woody fibre, paper, linen, etc., into glucose, which may in turn be converted into alcohol.
TABLE III.—PRINCIPAL ALCOHOLS.
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Chemical Name. | Source. | Formula. |Boiling Point
°F.
————————+———————————+———————+———————
1 Methyl Alcohol|Distillation of Wood |CH_{3}OH | 150.8
2 Ethyl " |Fermentation of sugar |C_{2}H_{5}OH | 172.4
3 Propyl " | " " grapes |C_{3}H_{7}OH | 206.6
4 Butyl " | " " beets |C_{4}H_{9}OH | 242.6
5 Amyl " | " " potatoes|C_{5}H_{11}OH | 278.6
6 Caproyl " | " " grapes |C_{6}H_{13}OH | 314.6
7 Aenanthyl " |Distillation castor oil|C_{7}H_{15}OH | 347.
| with potatoes | |
8 Capryl " |Essential oil hog weed |C_{8}H_{17}OH | 375.8
9 Nonyl " |Nonane from petroleum |C_{9}H_{19}OH |
10 Rutyl " |Oil of Rue |C_{10}H_{21}OH|
11 Cytyl " |Spermaceti |C_{16}H_{33}OH|
12 Ceryl " |Chinese wax |C_{26}H_{53}OH|
13 Melisyl " |Bees' wax |C_{30}H_{61}OH|
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Among a variety of other substances which have been and are still used for the production of alcohol in smaller quantities, are roots of many kinds, such as those of asphodel, madder, etc. Seeds and nuts have been made to yield it. It will thus be seen that the sources of this substance are practically innumerable; anything, in fact, which contains or can be converted into sugar is what is termed "alcoholisable."
Alcohol has become a substance of such prime necessity in the arts and manufactures, and in one form or another enter so largely into the composition of the common beverages consumed by all classes of people that its manufacture must, of necessity, rank among the most important industries of this and other lands.
Of the alcohols given in the above table only two concern the ordinary distiller, or producer of alcohol for general use in the arts. Methyl alcohol, the ordinary "wood alcohol," or wood naphtha, and Ethyl alcohol, which is produced by the fermentation of sugar and may therefore be made from anything which contains sugar.
Ethyl alcohol forms the subject of this treatise. Aside from its chemical use in the arts as a source of energy and as a fuel, alcohol will likely soon compete with petroleum, gasoline, kerosene, etc., under the Act of Congress freeing the "de-naturized" spirit from the Internal Revenue tax. This act and the de-naturing process are covered in the last chapters of