Summary.

Free nitric acid yields hydroxylamine when treated with tin, zinc, cadmium, magnesium, and aluminium. In presence of either hydrochloric or sulphuric acid the quantity obtained may be considerable, that is, at least, when the metal is either tin or zinc. Without a second acid only traces of hydroxylamine can be detected.

There is no reason to believe that the action of the hydrochloric or sulphuric acid upon the metal is instrumental in forming hydroxylamine. The second acid serves to decompose nitrate as fast as it is produced. In this way, (1) it holds the hydroxylamine in a state more stable than the nitrate; (2), it preserves the hydroxylamine from the destructive action of nitrous acid, by preventing that formation of this substance which would otherwise result from the reaction between a metal yielding hyroxylamine and its own nitrate; and (3), it determines the reduction of all the nitric acid to hydroxylamine by supplying the hydrogen for reproducing it, and so keeping it free to the last.

Metals act upon nitric acid in one of two ways, and are accordingly divisible into two classes. The one includes the metals silver, mercury, copper, and bismuth. The metals of this class form nitrite, water, and nitrate, and exert no further action, forming neither ammonia nor hydroxylamine. They do not convert their nitrate to nitrite. Their mode of action is to decompose the nitric acid into hydroxyl and nitroxyl, combining with these radicals to form hydroxide and nitrite, which, by secondary reactions, become water, nitrous acid, and metal nitrate. These metals therefore separate nitrogen from oxygen (hydroxyl) in decomposing nitric acid; they do not in this decomposition separate hydrogen from oxygen, just as they do not do so in any other case.

The other class of metals includes tin, zinc, cadmium, magnesium, aluminium, lead, iron, and the alkali-metals. These form ammonia and generally also hydroxylamine, but do not yield nitrite or nitrous acid with free nitric acid. On the other hand, they readily form nitrite by acting on their own nitrate. They exercise two actions, one upon the nitric acid itself, and one upon the hydroxylamine they have produced. They act first upon 7 mols. of the acid, separating, in the form of hydroxylamine, the hydrogen of six of them by forming nitrate, and leaving the seventh converted to water and the said hydroxylamine. This action occurs without evident break into successive stages. The second action of these metals is that in which they combine with hydroxylamine to form metal-ammonium hydroxide, which decomposes with water into metal hydroxide and

ammonia.

Nitrites have a constitution indicated by the name

nitronates,"

that is, they have their metal directly united to their nitrogen. They have the same radical -NO2- as nitrates have, these being its metaloxyl compounds.

LXII.—On some Compounds of Phenols with Amido-bases.

By GIBSON DYSON, Dalton Scholar of Owens College.

DALE and SCHORLEMMER, in their recent investigation on the action of aqueous and alcoholic ammonia upon aurin, discovered the remarkable fact that it is extremely difficult to separate the aurin from the amido-bases formed, by means of dilute acids. Hence they were led to conclude that the aurin combined with the amidobases, and they were able to confirm this view by the preparation of pure rosaniline aurinate (Chem. Soc. J., 1883, 1, 185).

Aurin being a phenol and rosaniline an amido-base, it appeared probable that analogous compounds of the phenols with different amido-bases might be obtained. A mixture in molecular proportions of phenol and aniline was therefore heated to the boiling point for a considerable time, and then left to cool. After some time large thin plates crystallised out, and finally the whole solidified to a crystalline mass. This, on recrystallisation either from alcohol or from petroleum-naphtha, yielded beautiful glistening plates melting at 29.5° (loc. cit.). At the request of Professor Schorlemmer I undertook the further investigation of these bodies and other compounds of phenols with amido-bases. The following are the results I have so far obtained :

I. Aniline Phenate, C,H,NH2.CH2OH.

Dale and Schorlemmer describe the preparation of this compound, which they obtained by heating together molecular proportions of aniline and phenol to the boiling point; but it is also formed in the cold on standing. The product was purified by recrystallisation, either from alcohol or from petroleum-naphtha, and is thus obtained in well-defined crystals, the best being deposited from the last-named solvent.

These crystals closely resemble pure naphthalene in appearance, and when pure melt at 30.8°, and boil at 181° C. Dale and Schorlemmer

give the melting point 29.5° and the boiling point 184.5°, but their substance had been purified only by pressing.

Determination of the Aniline.-In order to determine the aniline in this compound directly, the following three methods were tried, but failed to give satisfactory results.

1. The aniline was precipitated as the double chloride of aniline and platinum by means of platinum tetrachloride. This method failed, in consequence of the reducing action of the phenol upon the double salt formed.

2. An excess of dilute hydrochloric acid was added to a weighed portion of the salt, and then the mixture was boiled until all the phenol had been expelled. The aniline hydrochloride left was next precipitated as the double salt by platinum tetrachloride, and the precipitate obtained was washed with a mixture of pure alcohol and ether. The results obtained, however, were considerably too low, this being probably due to the volatilisation of some of the aniline together with the phenol.

3. Varrentrapp and Will's method failed to give good results, since it was found impossible to prevent phenol or substances possessing a similar reducing action on the platinum double salt passing into the bulbs. The only method which promised to give accurate results was the determination of free nitrogen by Dumas' method, and subsequent experiments bearing out this promise, this method was adopted in the analysis of this compound, and also in similar determinations required in the course of the investigation.

The following analytical numbers were obtained :

(a.) Before recrystallisation, purified by Pressing only.

(b.) After repeated recrystallisation from Petroleum-naphtha

Found, 7:58 per cent. Calculated, 7:48 per cent.

The carbon and hydrogen, as obtained by combustion, were as follows:

(1) substance, 0·213-CO2 : 0·601-H2O: 0·134.

(2) substance, 0·21-CO2: 0·5925-H2O: 0·1325.

II. Toluidine Phenate, CH,,CH,NH2.CН¿OH.

39

This compound was obtained by fusing together molecular proportions of paratoluidine and phenol; on cooling the mixture solidified to a soft mass, which was freely soluble in hot light petroleum-naphtha (b. p. below 90°). This solution was left to cool, whereupon it deposited well-formed needle-shaped crystals of the pure phenate, melting at 31.1°, some of which were from 2 to 3 inches in length. The following analytical results were obtained :—

Found, 6.99 per cent., mean of two determinations.

III. Naphthylamine Phenate, C10H-NH2.C6H2OH.

This body was obtained in a manner similar to that employed in the preparation of the aniline and toluidine phenates. By recrystallisation from light petroleum-naphtha (boiling below 90°) it is with difficulty obtained in well-formed needle-shaped crystals, possessing the characteristic smell of naphthylamine, and melting at 30·1o.

Substance, 0.253-CO2 : 0 7515-H2O: 0·145.

When pure ẞ-naphthol and aniline are heated together in the proportions required by the above formula, a fibrous mass is obtained resembling crude naphthol in appearance. It is but slightly soluble in cold, but more freely so in hot petroleum-naphtha, from which it is deposited on cooling in the form of a crystalline powder, melting at 82.4°.

(1) substance, 0-2035-CO,: 0·605-H2O: 0.118.

5.9

5.83

(2) substance, 0·221-CO2 : 0·65925— H2O: 0·1275.

V. Toluidine Naphthate, C,H,,CH3NH2.C10H, OH.

This compound was obtained in exactly the same manner as the aniline naphthate, which it closely resembles in appearance.