d. Chloroform readily reduces the hot potassio cupric solution (distinction from chloroethylidene and from alcohol).

e. Chloroform may be separated from slight mixtures of Ether, Alcohol, water, etc., as follows: To 10 parts of the impure chloroform, add 2 parts of concentrated sulphuric acid, and shake together occasionally for 24 hours. Remove the upper layer, add to it part of (crystallized) carbonate of sodium previously dissolved in 1 part of water, agitate and digest (cold) for half an hour, then remove the lower layer and distil it from part of freshly-burned lime.-Distillation from dry calcium chloride separates chloroform from alcohol.-To separate from Ethereal Oil (ethyl and ethylene sulphates), distil from animal charcoal.

198. CHLORAL HYDRATE. C ̧ÁC1‚O.H2O. Characterized by its sensible and physical properties (a), and its formation of chloroform (b), and of chloralide (c). It has, with alkalies, considerable reducing power (d). Separated from chloral alcoholate by its slight solubility in cold chloroform and its greater solubility in cold water.-Estimated from the amount of chloroform it produces (e).

a. A friable solid, crystallizing from solvents in transparent rhomboidal crystals, or congealing in a white crystalline mass, melting at about 60° C. (140° F.) and boiling at 95° C. (203° F.) -(the Alcoholate boils at 116° C.). It slowly sublimes, in the bottle, at ordinary temperatures. It is neutral in reaction, and of an aromatic, penetrating, and slightly acrid odor, and bitter, caustic taste. Melted in a spoon, over the flame, it does not take fire (distinction from the alcoholate). It is slightly deliquescent, readily soluble in 1 parts of water (the alcoholate dissolves sparingly in cold water); soluble in alcohol, ether, benzole, petroleum naphtha, bisulphide of carbon; slightly soluble in cold chloroform (the alcoholate freely soluble). It forms liquid mixtures with camphor, and with phenic acid, and a crystalline mixture with glycerin.

b. Fixed and volatile alkalies, and their carbonates, in solution, decompose chloral hydrate—the chloroform subsiding from the milky mixture.

CHCI,O.H,O+KHO=CHC1,+KCHо,+н,0

(100 parts chloral hydrate producing 72.2 parts of chloroform.) (Trichloracetic acid, also decomposed by alkalies into chloroform and formate, has an acid reaction, and boils at 195° C.)

c. Concentrated sulphuric acid separates, from about an equal weight of chloral hydrate, anhydrous chloral-the latter rising to the surface, as a pungent and irritating oily liquid, of spec. grav. 1.5.-Chloralide is formed when chloral hydrate (concentrated, if necessary, by distillation from chloride of calcium) is heated with about six times its volume of concentrated sulphuric acid, at 125° C., for some time. When cool, the mixture is diluted with six measures of water, and, if carbonized at all, extracted with ether. On evaporating the ether the chloralide (C,H,C1,O,) crystallizes in stellate groups of prisms (or in needles) which melt at 116° C. and burn at 200° C. with a green-edged flame.-In certain conditions, sulphuric acid changes chloral into metachloral (insoluble in water, alcohol, or ether).

d. Chloral hydrate, in the act of decomposition by ammonia, promptly reduces nitrate of silver as a specular coating.Aqueous solution of pure chloral hydrate does not within a few minutes perceptibly decolorize the permanganate of potassium solution, and does not at all affect argentic nitrate. The potassio cupric solution is reduced by chloral according to 197, d.

Quantitative.—e. Take 10 grams of the chloral hydrate, dissolve in the least quantity of water, and add, in a graduated tube holding 20 c.c., ammonia enough to be a slight excess for the absolute chloral hydrate taken, according to the equation in b (5 c.c. of water of ammonia of spec. grav. 0.90). Stopper tightly in the tube, which should be nearly filled by the liquid, and leave until the subsident layer no longer increases-four to twelve

hours. The c.c. of chloroform are multiplied by 1.5 for grams. Closer results are obtained by taking 50 grams chloral hydrate.

199. IODOFORM. CHI,. A sulphur-yellow solid, crystallizing in hexagonal plates, stars, and rosettes; melting, at 115° to 120° C., with partial vaporization and partial decomposition into carbon, hydriodic acid, and iodine. It has a saffron-like odor, reminding of chloroform and of iodine, and a taste like the same substances, becoming unpleasantly strong of iodine. It is soluble in 13,000 parts of water (to which it imparts a slight odor and taste), in 80 parts of cold or 12 parts of boiling alcohol of 80 per cent., in 20 parts of ether, and soluble in chloroform, bisulphide of carbon, fixed and volatile oils. The alcoholic solution is straw-yellow; the ether solution, gold-yellow; both solutions are neutral, and have a sweet-ethereal, burning taste and iodine-like after-taste.-It is difficultly and imperfectly decomposed by boiling aqueous potassa, but (WITTSTEIN) alcoholic potassa decomposes it, forming iodide and formate (see chloroform, b).

200. CROTON-CHLORAL HYDRATE. CH,C1,0. The trichlorinated aldehyde of crotonic acid.-Thin, dazzling-white plates, melting at 78° C., volatile in steam at 100° C., boiling at 163°. It has a sweetish, melon-like taste, and its vapor irritates the eyes. It is sparingly soluble in cold, freely in hot water, and soluble in alcohol and in glycerin. Potassa decomposes it with formation of potassic chloride and formate and dichlorallylene (C,H,Cl2).

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201. AMYLIC ALCOHOL. C,H,,O. Characterized by its sensible and physical properties (a); by its production of red sulphamylic acid (b); by its formation of odorous ethers (c).—It is separated from alcohol by fractional evaporation or distillation, or by adding water and extracting with ether (d); from water, in the slight proportions miscible, by adding petroleum naphtha or benzole, or by adding common salt (e).

a. A colorless and transparent liquid, of spec. grav. 0.816, boiling at 132-3° C. (270° F.), and having a sharp taste and a characteristic, pungent odor. Its vapor excites coughing, a few moments after it is inhaled.—It is soluble in about 40 parts of water, less soluble in solution of common salt, soluble in all proportions of alcohol, ether, chloroform, benzole, petroleum naphtha, fixed and volatile oils. It makes a slowly evanescent oil-spot upon paper.—It burns with a smoky flame.

b. When two parts of amylic alcohol are digested warm with three parts of concentrated sulphuric acid, sulphamylic acid, or amyl sulphuric acid is formed-having a red color and dissolving freely in water.

c. Distilled or digested hot with concentrated sulphuric acid and potassic acetate, the odor of "pear-oil" is developed —from formation of amyl acetate.-Distilled or digested with sulphuric acid and a little water and bichromate of potassium, the apple-odor of valeric aldehyde is first generated, and then the peculiar odor of valeric acid (42).

d. It is separated from (aqueous) ethylic alcohol, by adding an equal volume of pure ether, and then to the whole an equal volume (or enough) water to cause the ether to separate. The latter will contain most of the amylic alcohol. Benzole or petroleum naphtha may be used instead of ether.

e. If from 100 c.c. of commercial "fusel-oil" are slowly distilled 5 c.c., and this be agitated with a saturated solution of common salt, the separation of an oil-layer of 2.5 c.c. or over indicates that there is less than 15 per cent. of "proof spirit" in the fusel-oil taken.

202. “FUSEL-OIL" contains, besides amylic alcohol, small proportions of Butyric, Valeric, and volatile Fatty Acids, and of propylic and butyric alcohols.-In examination of spirits for fusel-oil, add 2 or 3 c.c. of potassa solution, to about 30 c.c. of the material, and evaporate by a gentle heat to dryness. Add 5 or 6 c.c. of sulphuric acid and nearly as much water: