532

PHOSPHOTRIETHYLIA, OR TRIETHYLPHOSPHINE.

first was closed with a cap of caoutchouc, is opened, and the ethereal solution of zinc-ethyl is distilled into the retort, after which the globe with the phosphorous chloride is fixed in its place; the trichloride is allowed to enter drop by drop, whilst the

retort is cooled by immersion in ice-cold water. The action is very violent. As soon as heat is no longer evolved by addition of the phosphorous chloride the decomposition is completed.

In the retort and the receiver are two layers of liquid: one a pale, heavy, straw-coloured viscid liquid, the compound of phosphotriethylia and zincic chloride; the other a colourless mobile fluid, which is a solution of phosphorous chloride in ether, and which may be poured off and used in a subsequent similar operation. In order to separate the phosphorus base, the compound is decomposed by means of caustic potash. For this purpose the mass in the retort is first diluted with water, then the retort is filled with hydrogen, and a concentrated solution of potash allowed to flow slowly into it. On subsequently distilling, in a very slow stream of hydrogen, phosphotriethylia passes over with the aqueous vapour, and forms a layer which floats on the top of the condensed water in the receiver.

Phosphotriethylia, by slow oxidation, is converted into a crystalline, volatile, very deliquescent mass, of a composition represented by the formula [(EH),P,O; (Fusing pt. 111°.2 (44° C.); Boiling pt. 464° (240° C.); Sp. gr. of vapour 4·60]: it corresponds to the oxide of stibiotriethyl (1199).

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Corresponding compounds, which contain sulphur (Є2H¿)P‚§, and selenium, may also be formed by the direct action of sulphur or of selenium upon the phosphorus base. The sulphide of phosphotriethylia is a volatile substance which fuses at 2010 (95° C.). It is soluble in hot water, from which it crystallizes in

remarkably beautiful needles. alcohol, as well as by ether and carbonic disulphide. Chlorine, bromine, and iodine likewise enter into direct combination with phosphotriethylia; 2 atoms of each of these elements combining with one atom of the base. Direct combination also occurs between hydrochloric, hydrobromic, and hydriodic acid, with phosphotriethylia; the hydrochlorate having the composition represented by the formula [(Є2H ̧),P,HCI]. Other monacid salts, such as the nitrate [(E,H,),P,HNO3], may be formed. These compounds may be crystallized, though with difficulty.

It is also freely dissolved by hot

On treating phosphotriethylia with ethyl iodide, a very powerful and almost explosive reaction occurs, and the mixture, on cooling, yields a crystalline mass of phosphotetrethylium (tetrethylphosphonium) iodide, which, when decomposed by oxide of silver, yields a strongly alkaline solution of the hydrated oxide of the base [(Є,H.)',PHO]; it has a bitter phosphoric taste, and yields crystallizable deliquescent salts. When this hydrated base is heated, it gives off a compound of carbon and hydrogen, and at a higher temperature furnishes crystals of the oxide of phosphotriethylia (Є2H¿) ̧P‚Ð.

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Both arsenic and antimony form with ethyl and methyl, and the other alcohol radicles, compounds which combine with oxygen, and possess basic properties as powerful as those of many of the metallic oxides (1191-1200).

4. Polyatomic Bases.

(1382) Recent researches, especially those of Hofmann, have shown that, in addition to the monatomic bases, or bases formed upon the type of a single atom of ammonia, others may be obtained, which are produced by substitution from two, from three, or even from a still larger number of atoms of ammonia. So that we have diatomic and triatomic bases, or diammonias and triammonias formed from the diatomic and triatomic alcohols, just as the monammonias are from the monatomic alcohols.

When, for instance, ethylene dibromide is decomposed by ammonia, a complex reaction occurs; but among the products two substances are always present as hydrobromates; viz., ethylene-diamine, or ethylenia, and diethylene-diamine, or diethy

lenia.*

Each of these bases is formed from two atoms of

* In studying these diamines or compounds on the type of diammonium, Hofmann found it far more advantageous to use phosphotriethylia than ammonia as the compound from which they were formed. The number of compounds ob

534

HYDRATED DIETHYLENIUM

OXIDE.

ammonia, and requires two atoms of a monobasic acid for its saturation. This formation may be illustrated by the subjoined equations:*

2 H ̧N + (Є,H)"Br2 = [(Є,H)"H ̧N2]" 2 HBr;

Ethylene dibromide.

Diethylenia hydrobromate.

4H ̧N + 2 [(Є2H ̧)”Br2] =

=

[(Є2H)"2H,,N2]" 2 HBr + 2 H ̧NBr.

(1383) Diethylenia is a base which was discovered about the same time by Cloez and by Natanson, and was named acetylia; but its true nature was first explained by Hofmann.

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Hydrated Diethylenium Oxide [(E,H)",H ̧Ñ‚Ð ̧н,0].—When Dutch liquid (ЄH ̧Cl2) is heated for some hours to a temperature of 302° (150° C.) in a sealed tube, with about 5 times its bulk of a concentrated solution of ammonia, it is completely decomposed; a yellow liquid is formed, and crystals of chloride of ammonium are deposited in abundance: if these be separated by filtration through muslin, and the mother liquor be treated with oxide of silver, it yields a decidedly alkaline solution, which absorbs carbonic acid from the air. The new base thus obtained is not volatile, its salts have a feebly acid reaction, and do not crystallize. If its chloride be mixed with a solution of platinic chloride, it yields a wax-like mass, which has the composition of the double chloride of platinum and diethylenium [(E,H)",H,N,Cl,,PtCl].

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tainable from phosphotriethylia by substitution is much smaller than that obtainable from ammonia, inasmuch as the three displaceable atoms of hydrogen which ammonia contains have been already displaced in the phosphorus base.

When ammonia is acted upon by means of ethylene dibromide, compounds may be obtained in which the hydrogen may be successively displaced by the diatomic radicle (e,H,)", and by the monatomic radicles (E,H,)', (Є,H,Br)', (He)'. These different compounds are liable to be obtained mixed in every proportion (Phil. Trans. 1860), so that the difficulties of the investigation are sufficient to discourage even the most practised skill, and often to baffle all the resources of analysis.

Hofmann has shown that there is no limit to the number of atoms of ammonia which may be thus welded into one, and he has indeed succeeded in grouping together as many as eight atoms of ammonia into one atom of a compound base. The mode in which he has effected this will be readily understood from the symbols which follow:

In the formula just given six atoms of ammonia are represented, placed side by side, all linked together into one molecule by the five atoms of the dyad radicle ethylene.

DIETHYLENIA (DIETHYLENE DIAMINE).

535

Diethylenium chloride, if slightly acidulated with sulphuric acid and mixed with nitrite of silver, furnishes aldehyd in abundance :

:

(Є2H ̧) ́ ́‚H ̧N ̧Cl2+2 AgNO,=2 €2H ̧0+2 N2 +2 H ̧→ + 2 AgCl.

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This reaction corresponds to that of nitrous acid on aniline, by which carbolic acid (H) is reproduced, whilst nitrogen and water are liberated.

It may be remarked that hydrated diethylenium oxide is isomeric with aldehyd-ammonia, although so different from it in properties :

2 2 2

Diethylenia, or Diethylene diamine (EH)"2H2N ̧; Sp. gr. of liquid 0975; of vapour 1522; Rel. wt. 43; Boiling pt. 338°. (170° C.; Hofmann).—If an alcoholic solution of the hydrated diethylenium oxide be distilled to dryness in a retort, and the temperature be then raised to about 300°, water again begins to escape, and at a temperature of 428° (220° C.) yellowish oily drops of diethylenia pass over. This body has a peculiar persistent odour, which is ammoniacal, and at the same time recalls that of aldehyd. It does not become solid at -13° (— 25° C.). It is inflammable, and burns with a bluish-white flame. It is insoluble in ether, but freely soluble both in water and in alcohol. Sodium exerts no action upon diethylenia at ordinary temperatures. Dry reddened litmus-paper does not become blue even when immersed in it; but if the base be treated with acids, it forms salts which are identical with those of diethylenium oxide. If caustic potash be added to a solution of these salts, the liquid does not emit the odour of diethylenia, but exhibits the properties of a solution of hydrated diethylenium oxide. An aqueous

solution of diethylenia produces in a solution of the salts of zinc, a white precipitate which is soluble in excess of the base. With salts of copper it gives a pale yellow precipitate, which is partially soluble if diethylenia be added in excess, forming a bright blue liquid. It occasions a white precipitate in solutions of the salts of silver, but the precipitate is readily dissolved by an excess of the base; and if the solution be gently warmed, a mirror-like coating of reduced silver is formed on the sides of the vessel.

It is remarkable that diethylenium oxide should be so permanent a body as to require a temperature of 302° (150° C.) for

536

ETHYLENIA-OTHER DIATOMIC BASES.

its decomposition, although the corresponding compound of ammonium undergoes decomposition as soon as it is formed at ordinary temperatures. Diethylenia corresponds exactly with two atoms of ammonia, and like it does not form salts until it has assimilated the elements of water.

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(1384) Ethylenia, or Ethylene diamine (EH)"H ̧N; Boiling pt. 253'4 (123° C.); Sp. gr. of vapour 2:00; Rel. wt. 30).—Cloez believed that formyl (EH) entered into the composition of a base termed formylia, homologous with acetylia; but Hofmann has proved that this base contains one atom of hydrogen more than that required by such a formula, and that it is really as given above. If diethylenia be treated with ethyl iodide, diethyl-diethylenia is obtained, a base which may be represented by the formula (Є2H ̧)",(¤ ̧H.) ́‚N. Diphenyl-diethylenia (EH)",(¤ ̧H.)',N, is procured by treating Dutch liquid with aniline instead of with ammonia ::

Dutch liquid.

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2,H,Cl2+4H,N= 2 (e,H,N,HCI) + (¤,H,),"(EH)'2N2, 2 HCI.

Corresponding bodies may be obtained by treating Dutch liquid, or ethylene dibromide, with methylia, ethylia, and other analogous bases.

Diethylenia also produces compounds corresponding to the amides. For instance, when butyric ether is mixed with an alcoholic solution of diethylenia, crystals of butyric diethylenamide (H) N2 are formed.

(1385) Other bases containing oxygen were obtained by Wurtz by acting upon ammonia with successive quantities of ethylene oxide (1215); and these, though obtained from a diatomic alcohol, correspond to a single atom of ammonia :

(Є2H ̧Ðн)H2N; (¤ ̧H ̧→H),HN; and (Є,H ̧→H),N.

If the third of these bases be further acted upon by ethylene oxide, a fresh set of bases may be obtained, corresponding to the condensed glycols, or polyethylene alcohols, such as—

(Є2H ̧¤H)'2[(Є2H ̧→),H]'N; (¤‚H ̧OH)'[(¤‚H ̧→),H]'2N,

and so on.

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At present little is known of these bases, but the existence of oxidized radicles within them has some interest, in relation to the as yet unknown constitution of many natural vegetable bases which contain oxygen.