C2H...1-1 SO. H20 = H,SO. C21-15.0H.
This process is of considerable theoretic inter est, and is said to be in commercial use in Rus sia. Until carbide of calcium (from which acetylene is prepared) can be had more cheaply, however, it can hardly be successfully used in the United States. (See DENATURED ALCOHOL).
2. Wood Alcohol, or Methyl Alcohol.— A colorless, inflammable liquid, strongly resem bling ethyl alcohol in its general properties. It burns with a flame resembling that of grain alcohol, but with sensibly less evolution of heat. It is far cheaper than pure grain alcohol, be cause there is no excise tax upon it; in many uses it may be substituted for grain alcohol with success, its solvent powers being very sim ilar. It cannot be used internally, however, as it is of a poisonous nature, and has a peculiar selective action upon the optic nerve, in which It often induces a condition of permanent atrophy with consequent total blindness. Methyl alcohol is obtained by the dry distillation of wood. The process, as carried out in New York State, is substantially as follows: Hard wood is cut into cordwood size and allowed to season thoroughly, two-year-old wood being dry enough to yield excellent results. Beech, maple and birch are most commonly used, birch being the poorest of the three, because it yields a larger proportion of objectionable tarry matter. The seasoned wood is placed in retorts of cast iron or sheet steel, which are cylindrical in general shape, and large enough to hold rather more than half a cord each. A slow fire is then built under the retorts, its intensity being gradually increased as the distillation pro gresses, and regulated so that at the end of from 12 to 18 hours nothing remains in the retort but charcoal. The distillate is passed through a condenser, by which a portion is condensed into a watery fluid, while another and very considerable portion passes through in the form of a permanent, non-condensable gas. The non-condensable part consists largely of marsh gas, hydrogen, carbon-dioxide and carbon-monoxide, together with smaller amounts of acetylene and numerous other substances. No attempt is made to utilize this portion of the product except as fuel. The portion that condenses consists largely of acetic acid and methyl alcohol, together with acetate of methyl and acetone, and a considerable quantity of tarry matter. The condensed distillate is passed
into settling-tanks, where it is allowed to re main until the greater part of the tarry matter has subsided. The lighter part is then drawn off and saturated with slaked lime to fix the acetic acid. A second distillation expels the methyl alcohol, which is recovered by means of a condenser and shipped to the refiners in iron tanks, being known to the trade in this form as °wood spirit.' The acetate of lime remaining behind is then recovered by evapora tion and spread out upon a heated floor to dry.
Acetate of lime, as it comes from the alcohol manufacturer, is brown in color, from the tarry impurities that it contains. It is used in the manufacture of acetic acid and the various ace tates (notably those of iron and aluminum) that are used in dyeing and in printing upon cloth. The impure methyl alcohol, or °wood spirit,' that is shipped from the factory to the refiner, usually contains 80 per cent of alcohol and 20 per cent of water. The yield of spirit of this strength varies greatly, according to the skill and care exercised by the manufacturer; but in the best plants it may be taken at from eight to nine gallons per cord of good wood. Crude wood spirit contains considerable empy reumatic matter as well as acetone, acetate of methyl and acetate of ammonia. Pure methyl alcohol may be prepared by saturating the crude spirit with fused calcium chloride (CaCI,) and heating in a water-bath. Methyl alcohol com bines with calcium chloride under these condi tions, forming a compound which can be readily purified, and from which the alcohol can again be recovered by distilling with water. A final distillation over quicklime will give the alcohol in its anhydrous or °absolute" state. Pure methyl alcohol, free from water, has a specific gravity at 32° F. of 0.8101. Its chemical for mula is CH..OH ; it is the hydrate of the organic radical °methyl" (CHO, being analogous in this respect to ethyl alcohol, which is the hydrate of the organic radical °ethyl" (C,H5). It boils at about 151° F. under ordinary atmospheric pressure.