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ETHYL SELENIDES AND TELLURIDES.

2 (Є2H ̧HS)+HgO= [(E2H2),S,HgS] + H„Ð.

The corresponding compound of gold is white and gelatinous; that of platinum is bright yellow, and that of lead [(Є2H ̧),S,PbS] is yellow and crystalline.

(1148) Selenium and tellurium each form compounds with ethyl, corresponding to diethyl sulphide; they may be obtained by distilling potassic selenide or telluride with potassic ethylsulphate. It is, however, to be remarked that both the selenide and the telluride of ethyl combine with chlorine, bromine, and iodine; and they become oxidized, and form salts with the oxyacids, just as though they were metallic bodies. In fact, they present many chemical analogies with the compounds which arsenicum, antimony, bismuth, and other metals form with ethyl (1191 et seq.).

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A compound of selenium (Є2H,HSe), corresponding in composition and properties to mercaptan, is formed during the operation of preparing diethyl selenide.

These sulphur and selenium compounds with ethyl are analogous to the alcohols and ethers, or oxygen compounds of ethyl. Each sulphur compound furnishes a volume of vapour equal to that of the molecule of the corresponding oxygen compound :

Each molecule of alcohol, when decomposed by phosphoric sulphide, yields a single molecule of mercaptan, an atom of sulphur changing places with the atom of oxygen in the alcohol; but if the molecule of alcohol be decomposed by phosphoric chloride, the atom of oxygen is displaced by two atoms of chlorine, and a molecule of ethyl chloride with one of hydrochloric acid is formed :

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CYANIDE OF ETHYL-NITRILES.

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(1149) Cyanide of Ethyl, Ethyl Cyanide, Hydrocyanic Ether, or Propionitrile (Є,H,Cy=Є,H,N). Sp. gr. of liquid 0787; of vapour 1928; Rel. wt. 27'5; Boiling pt. 190°4 (88° C.)—This compound is obtained in a manner analogous to that directed for the preparation of the foregoing bodies, viz., by the distillation of well-dried potassic ethylsulphate with two-thirds of its weight of potassic cyanide. A still better method consists in heating a solution of 2 parts of ethyl iodide in 8 of alcohol with I part of potassic cyanide, condensing the vapours, and allowing them to fall back into the retort as long as they show any sign of iodine. The product is washed with water, and rectified by the heat of the water bath. It is a colourless, very poisonous liquid, When ethyl cyanide is treated with a boiling solution of potash, the elements of water are assimilated, ammonia is evolved, and potassic propionate is formed :

of an alliaceous odour.

A similar mode of decomposition is observed to occur with all the hydrocyanic ethers when treated with caustic potash : they all combine with the elements of water, and yield a salt of one of the acids homologous with formic acid; methyl cyanide thus yields potassic acetate :

and amyl cyanide in like manner furnishes potassic caproate :

This method of forming the higher terms of the homologous series from those below them is one of considerable interest.

The hydrocyanic ethers (the nitriles of some chemists), as a class, may also be obtained by a process of dehydration, from the acids to which they correspond; that is to say, if the ammoniacal salts of the acids homologous with the formic, be distilled with phosphoric anhydride, or be otherwise treated in such a manner as to deprive one atom of the salt of two atoms of water, they yield one of the hydrocyanic ethers (1340, 1351), thus:

Ammonium formiate.

Hydrocyanic acid.
(Hydric cyanide.)

H ̧NCHO,-2 H2O = H,EN

Ꮎ

= (ЄHN, Formio-nitrile);

and in this manner the hydrocyanic ethers of several series of alcohols have been obtained, although the corresponding alcohols are at present unknown.

The action of potassium upon hydrocyanic ether is remarkable. If the ether be allowed to fall drop by drop upon potassium contained in a flask fitted to a vertical condenser, by means of which any part of the ether which escapes decomposition is allowed to fall back upon the potassium, ethyl hydride (H,H) is formed, whilst potassic cyanide is produced, and an alkaline base termed cyanethine (HN) remains in the flask (Frankland and Kolbe). This base is polymeric with hydrocyanic ether. It crystallizes from boiling water in pearly scales, and forms salts with the acids. The nitrate (E,H,,N,,HNO3) crystallizes in large colourless prisms, which are neutral in their reactions.

The hydrocyanic ethers of the other alcohols when treated with potassium appear to furnish compounds homologous with cyanethine.

(c) Ethylic Ethers of the Oxyacids.

(1150) Sulphate of Ethyl, or Diethyl sulphate, or true Sulphuric Ether [(E,H,),SO]. Sp. gr. of liquid 1'120.-This compound was first obtained by Wetherill, by the direct combination of ether with sulphuric anhydride. The vapours of the anhydride are transmitted into a flask containing ether, which is kept cool by ice; the syrupy liquid thus produced is agitated with its own volume of ether and with four times its bulk of water; when left at rest the sulphate of ethyl rises to the surface; it is purified by agitation with milk of lime, washed, filtered, and dried in vacuo. Sulphuric ether is an oily liquid, of burning taste and ethereal odour, resembling that of peppermint. It is scarcely possible to distil it without occasioning its decomposition, as a temperature of 270° or 290° resolves it into alcohol, sulphurous acid, and olefiant gas.

Sweet or heavy oil of wine appears to be a mixture of the foregoing compound with some hydrocarbons polymeric with olefiant gas; it is obtained during the latter stages of the distillation of ether. If this oil be treated with a solution of

NITRIC AND NITROUS ETHER.

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potash, it is decomposed; potassic ethylsulphate, and a hydrocarbon, termed etherol (E1H32?) rises to the surface. This hydrocarbon, known also as light oil of wine, is polymeric with olefiant gas, and forms a colourless liquid which has a sp. gr. of o'917 ; it boils at 536° (280° C.), and is readily soluble in ether and in absolute alcohol. When exposed to a temperature of -30°, it usually deposits semitransparent, friable, colourless prisms of an isomeric hydrocarbon named etherin; these fuse at 230° (110° C.), and boil at 500° (260° C.); they are lighter than water, in which they are insoluble, but are dissolved freely by alcohol and by ether.

(1151) Nitric Ether, Ethyl Nitrate (Є,H,NO). Sp. gr. of liquid 1112; Boiling pt. 185° (85° C.).-Millon obtains this substance by gently heating a mixture of one volume of nitric acid, of sp. gr. 1'40 (to which a few grains of nitrate of urea have been added in order to prevent the formation of nitrous acid), and two volumes of alcohol, of sp. gr. 0842; the quantity of the mixture operated on should not exceed a quarter of a pint, or about 150 cubic centimetres; under these circumstances the operation proceeds quietly. The first portions of the distillate contain little except alcohol, but as soon as the liquid which distils over becomes turbid on the addition of water, the receiver must be changed, and the nitric ether collected separately: the distillation must be stopped when about three-fourths of the liquid have passed over, in order to prevent the ether from becoming mixed with secondary products, which cannot be removed without difficulty. The ether is purified by agitation with a weak solution of alkali, and rectified from chloride of calcium. Nitric ether is a colourless liquid of an agreeable odour, and a taste at first very sweet, but followed by a bitterish after-taste. Its vapour burns with a white luminous flame, and if heated to a little beyond its boiling point, it is decomposed with explosion, on the approach of a light.

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(1152) Nitrous Ether, or Ethyl Nitrite (Є,H.NO). Sp. gr. of liquid 0947; of vapour 2.627; Rel. wt. 37'5; Boiling pt. 62° (16°6 C.).—The Spiritus Etheris Nitrosi of the Pharmacopoeia consists of a solution of this ether in alcohol; it has long been used. as a therapeutic agent. The safest method of preparing the pure ether consists in introducing into a retort containing copper filings, one measure of alcohol (sp. gr. 0·83), to which one measure of nitric acid of sp. gr. 136 is gradually added. The reaction of nitric acid upon alcohol begins at a very moderate heat, and is apt to become extremely violent, therefore no external heat should.

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PERCHLORIC ETHER-SILICIC ETHERS.

be applied during the distillation, after the reaction has once commenced. The vapours which are evolved contain hydrocyanic acid; they should be transmitted through a washing bottle containing water, then through a long bent tube filled with chloride of calcium, and finally should be condensed in a flask cooled by ice. Nitrous ether is of a pale yellow colour; it has an agreeable odour of apples. When this ether is kept in contact with water, it speedily becomes decomposed, and an acid is formed which was formerly supposed to be the malic. Debus has, however, shown that the result is a complicated one, nitric, formic, acetic, oxalic, glycolic, and glyoxalic acid (H?) being formed, whilst glyoxal (E,H,,), the aldehyd of glycol, is liberated, together with other aldehyds. (Phil. Mag. Nov. 1856.) A solution of ferrous sulphate becomes blackened when mixed with nitrous ether.

Nitrous ether is decomposed by transmitting its vapour. through a red-hot tube, when it gives rise to a variety of products, among which are hydrocyanate and carbonate of ammonia, derived from the reactions of the nitrogen upon the carbon and hydrogen.

(1153) Perchloric Ether, or Ethyl Perchlorate (E,H ̧CIO).— This singular compound cannot be prepared without considerable danger, since it explodes with extraordinary violence when heated to a little beyond 212°; a similar result is produced by friction or by a sudden blow, and sometimes it explodes by merely lifting the vessel which contains it, or even without any assignable cause. In order to obtain it, a few grains of crystallized baric ethylsulphate are placed in a tube retort with an equal weight of baric perchlorate, and are cautiously distilled by the heat of an oil bath, which must not be allowed to exceed 338° (170° C.) The ether is heavier than water, and has a sweetish pungent taste, somewhat resembling that of cinnamon. Its boiling point is not known with accuracy, but it is above 212°. The explosive character of the compound depends upon the large proportion of oxygen which it contains in union with chlorine, for which the attraction of oxygen is very small, whilst hydrogen has a powerful attraction for both chlorine and oxygen; the chlorine forms hydrochloric acid with 1 atom of hydrogen, and the oxygen is sufficient to convert the carbon into the form of carbonic oxide and the remaining hydrogen into water; ¤H,Cl1=2 ЄO+2H2O+ HCl.

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(1154) SILICIC ETHERS.-Few of the ethers are more remarkable than those obtained by Ebelmen with silica. In these compounds the polybasic character of the acid is preserved. Tetrethyl Silicate [(EH),SiO], formerly Dibasic Silicate of