The percentage of nitrogen is too low, but the fact that the other constituents are all rather in excess of the amounts required, and the impossibility of purifying the substance, will, I think, account for this.

The silver-compound is precipitated as a bulky orange-coloured powder on adding nitrate of silver to the solution of the original substance. It must be washed with cold water, in which it is slightly soluble, and dried in vacuo.

I. 7287 grm. heated with strong nitric acid till completely decomposed, gave 248 grm. AgCl, or 8:42 p. c. chlorine.

II. Filtrate from the above, mixed with hydrochloric acid, gave 0835 grm. AgCl, which, added to the former quantity, gives 3315 grm. AgCl to represent the whole amount of silver in the substance, or 34.24 p. c.

III. 4615 grm. decomposed with hydrochloric acid gave 209 grm. AgCl, or 34:08 p. c. silver..

The formula 3CNO2CICу2 + 4AgNO3 + 8H2O requires 34-27 p. c. silver, and 8.45 p. c. chlorine.

The compound when heated to 80° decomposes suddenly with great frothing, leaving a very bulky residue. The water contained in it may, however, be removed by heating it under boiling water; it then fuses into dark-red drops. A quantity of cold water is then added, and the substance taken out and dried with filter-paper, and afterwards in vacuo.

I. 693 grm., treated with nitric acid as before, gave 259 grm. AgCl, or 9.25 p. c. chlorine.

II. Filtrate from the above, mixed with hydrochloric acid, gave 096 grm. AgCl, which, added to the former amount, is 355 grm., or 38.55 p. c. silver.

The formula 3CNO2CICу2 + 4AgNO, requires 38.69 p. c. silver, and 9.53 p. c. chlorine.

A compound very similar in appearance is formed with nitrite of silver. It is, however, more stable, sustaining the heat of the water-bath without decomposition.

The original substance, as before mentioned, is very unstable ; its watery solution slowly deposits solid products, with evolution of gas-bubbles, and on heating with acids or alkalis, the decomposition is very rapid, and appears to be mainly the same in both cases. When an alkali is used, however, the mixture becomes very dark, and large quantities of the azulmic compounds are formed. The most definite reaction is obtained by heating the

watery solution with a few drops of dilute nitric acid, when it rapidly becomes lighter in colour, and a large quantity of gas is given off with effervescence, the products of the decomposition giving additional evidence of the composition of the substance.

In the remaining solution was found a considerable quantity of oxalic acid, recognized by the usual tests, and by the analyses of a lead and a barium salt.

The gas given off consists principally of carbonic acid and nitrogen, containing also vapour of hydrocyanic acid. After treatment with potash, the remaining nitrogen was found to be slightly inflammable. On passing it over red-hot oxide of copper, water was deposited in the front of the tube, and the gas collected over mercury contained a further quantity of carbonic acid. Another portion passed through an empty tube heated to redness gave a quite appreciable quantity of hydrocyanic acid. From these indications it may be concluded that the inflammability of the gas is owing to the presence of vapour of methylic cyanide.

The following equations represent the two reactions, which appear to take place at the same time ::

CNO,CICу2+4H2O NH4Cl + CO2 + N2 + C2H2O4 + H2

=

2

2

CNO2CICу2 + 6H = CH2Cy+ HCy+HNO2 + HCl.

In addition to these main products of the action of acids on the substance, I have, by extracting the neutralised solutions with ether, obtained small quantities of at least three solid crystalline bodies containing carbon, hydrogen, chlorine, oxygen, and high per centages of nitrogen; but I can only indicate the existence of these bodies, the separation and purification of which were found to be unusually difficult, both from the nature of the substances, and the very minute quantities formed.

In conclusion, my best thanks are due to Mr. John Williams for the preparation of the greater part of the chloropicrin used in these experiments.

356

XXXV.-Note on the Hydrocarbons contained in crude Benzol.

By C. SCHORLEMMER.

By treating with concentrated sulphuric acid the light oils formed in the destructive distillation of cannel-coal at a low temperature, I obtained a series of hydrocarbons of a high boiling point, having the general formula 2(CH2-2), which, as I have pointed out in a communication to the Royal Society, are formed by the condensation of hydrocarbons of the acetylene series CnH2n-2*. I have found that these hydrocarbons are also contained in the oils obtained in the manufacture of coal-gas, which consist chiefly of the members of the benzol series. A large quantity of crude benzol was obtained by fractional distillation, which boiled between 80°-82°C. Bromine was added, as long as its colour disappeared. The bromides thus formed could not be separated completely from the benzol by distillation, as they undergo decomposition with evolution of hydrobromic acid and separation of carbonaceous matter, even below the boiling point of water. The greater portion of the benzol was therefore removed at as low a temperature as possible, and the remaining mixture heated with sodium. The mixed hydrocarbons thus obtained were again treated with bromine and then distilled. As soon as the benzol had distilled over, the temperature rose quickly up to 200°C., and between this temperature and 220°C. the remaining liquid came over. This liquid, which on analysis was found to contain 64.3 % Br., is a mixture of several bromides, the greater portion of which consists of C6H10Br2 (66.1% Br.). On adding an excess of bromine, heat is evolved, and after some time, white needle-shaped crystals separate out, the quantity of which increases for some days, until nearly the whole is converted into a solid mass. By washing with cold alcohol, in which the crystals are only sparingly soluble, the excess of bromine and the liquid bromides (bromides of hexylene and heptylene) can be removed, and on recrystallisation from boiling alcohol, perfectly white needles are obtained, sometimes several inches long, which melt at 112°C., and distil without

decomposition at 318°C. (corrected). Their composition is C6H10Br4, as the following bromine determination shows: 0.1970 substance gave 03612 bromide of silver and 0.0043 metallic silver.

From these experiments it follows, that crude benzol contains (besides members of the olefine series) the hydrocarbon C6H10, which is very likely identical with hexoylene, described by Caventou,* which boils at 80°-85°C. These hydrocarbons, which combine directly with bromine, adhere obstinately to benzol, even when it has been purified by treatment with concentrated sulphuric acid, and by repeated freezing and pressing out the portion of the remaining liquid; they may, however, be removed by adding bromine, as long as its colour disappears, treating with caustic potash and rectifying. A perfectly pure benzol may thus be obtained, boiling constantly at 81°C., which gives a nearly colourless nitro-benzol and dissolves in pure concentrated sulphuric acid with hardly any coloration. The oils obtained from gas-tar contain the hydrocarbons of the acetylene series in a much smaller proportion, than those formed in the distillation of cannel coal at a low temperature. I am at present engaged in experiments to isolate these hydrocarbons from Boghead naphtha.

XXXVI.-Note on Ethyl-hexyl Ether.

By C. SCHORLEMMER.

WHEN chloride of hexyl is heated in a sealed tube with an alcoholic solution of potash, chloride of potassium separates out; and on adding water to the liquid, a light oil is obtained, which according to Cahours and Pelouzef consists chiefly of hexylene, but also contains other substances. In the preparation of hexylene according to this method, I obtained some quantity of a liquid of a higher boiling point, which on fractional distillation over sodium (in order to remove traces of alcohol) was found to con+ Ann. Ch. Phys. (4), i, 27.

Compt. rend. lix, 449.

sist almost entirely of a compound boiling constantly at 131°-133°, and which on analysis gave numbers agreeing with the formula C,H180;

0.4385 substance gave 1·190 carbonic acid and 0.549 water.

The mode of preparation shows that this substance is ethylhexyl ether C2H

CHI 13

O.

Ethyl-hexyl ether is a colourless, mobile, highly refracting liquid, possessing a strong ethereal smell resembling that of ethyl-amyl ether. The specific gravity was found to be

By acting on chloride of hexyl with an alcoholic solution of potash, two reactions, therefore, take place, viz.:

(1) CH13C1+ KHO = C6H12 + H2O + KCl.

The latter reaction corresponds to Berthelot's mode of the formation of common ether by treating bromide of ethyl with an alcoholic solution of potash,* and to Balard's reaction for the production of ethyl-amyl ether by acting with the same re-agent upon iodide of amyl,† and also to Guthrie's mode of preparing ethyl-amyl ether by heating iodide of ethyl with a solution of caustic potash in amyl alcohol.‡

* Ann. Ch. Pharm. xcii, 351.

Ann. Ch. Phys. [3], xii, 302. Balard considered this ether as amyl ether and some French chemists still adhere to this opinion (vide Frémy et Pelouze, Traité de Chimie v, 524) although Williamson pointed out its true constitution many years ago.

Phil. Mag. (4) xiv, 186.