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134
IX.-On the Alleged Existence of a Second Nitroethane.
By WYNDHAMR. DUNSTAN,Professor of Chemistry to the Pharma- ceutical Society, and T. S. DYMOND.
IN 1873, Victor Meyer (Annalen, 171, 1-56) found that by the interaction of ethyl iodide and silver nitrite two compounds of the formula C2H,N02were produced. One of these he recognised as the previously known ethyl nitrite (b. p. 16*5"),the other as a new sub- stance (b. p. 113"),to which he gave the name of nitroethane. In this interaction much heat is evolved, and the temperature soon rises far above the boiling point of ethyl nitrite. In order to complete the change, the mixture is heated for some hours with a reflux condenser on a water-bath, when the greater part of the ethyl nitrite will escape unless special means are adopted to condense it ; some, how- ever, remains dissolved in the nitroethane, generally with a little ethyl iodide, and on fractionating the liquid a mixture of these three substances will distil below 100". According to Meyer, the two isomerides are formed in equal quantities. More recently the interaction of ethyl iodide and dry silver nitrite has been studied, under somewhat different conditions, by Kissel" (Journ. Russ. Chcm. Xoc., 1882, 226-230; and 1884, 135-140) ; he adds dry silver nitrite, in small quantities at a time, to the ethyl iodide cooled to O", until no further action ensues. The mixture is kept cool and shaken during one day, great care being taken to avoid Downloaded by University of Rochester on 12/04/2013 22:39:19. any permanent rise in temperature. Under these conditions, accord- Published on 01 January 1888 http://pubs.rsc.org | doi:10.1039/CT8885300134 ing to Kissel, no ethyl nitrite is formed, but when the mixture is dis- tilled, a considerable quantity of liquid comes over between 29" and :30°. This fraction is redistilled between 28" and 35O, washed with water, a solution of silver nitrate, and a weak sodium carbonate solution; it is then heated with silver nitrate, and distilled from dry calcium nitrate. The liquid, it is stated, now boils constantly at 29-30", and on combustion yields results agreeing with the formula C2HsN02. This substance is said to resemble in its properties both ethyl nitrite and nitroethane, but is characterised by its chemical reactions as a nitro-compound. It yields a crystalline sodium- derivative, is violently acted on by hydrochloric acid with the production of a new compound, and forms with solution of ferric chloride a blood-red colour, with solution of copper sulphate a clear
* Kissel's papers hare been consulted in the original, and I must take this opportunity to thank my friend Sir Nicholas Elphinstone, to whom I am greatly indebted for a, translation from the Russian.-W. R. D. View Article Online THE ALLEGED EXISTENCE OF A SECOND NITROETHANE. 135 green, and with a solution of silver nitrate a light-yellow turbidity. As regards the nitroethane proper (b. p. 113"), of which, according to Meyer, half the total amount of liquid consists, Kissel alleges that a, yield of from 54 to 66 per cent. may be obtained by adopting the process he has described, the remainder of the liquid being the new isomeride. Kissel also claims to have obtained a corresponding com- poiind (b. p. 43-44") by the interaction of isopropyl iodide and silver nitrite. Kissel's description of the properties and reactions of the " second nitroethane " at once suggests the idea that it is merely a mixture of ethyl nitrite with nitroethane, although it is true that some of the alleged facts are inconsistent with this view. We have lately had occasion to prepare a comparatively large quantity of nitroethane, and we thought it worth while to repeat Kissel's experiments. Dry silver nitrite was gradually added to 180 grams of ethyl iodide cooled below 0", until there was no further evolution of heat, the mixture was then frequently agitated at a low temperature during one day. No gas escaped. The distillation flask containing the mixture was connected with a condenser, and the temperature slowly raised. Between 16" and 17" a gas was evolved which possessed all the properties of ethyl nitrite, It burned with a yellowish flame, was absorbed by alcohol, and a3tonce liberated iodine from an acid solution of potassium iodide, nitric oxide being set free. The apparatus was now connected with two bulb-condensers, and these were joined to two wash-bottles containing alcohol. Between 19" and 40" a small quantity of liquid condensed; it was tested for ethyl nitrite and nitroethane, both of
Downloaded by University of Rochester on 12/04/2013 22:39:19. which were found ; the nitroethane was detected by first destroying
Published on 01 January 1888 http://pubs.rsc.org | doi:10.1039/CT8885300134 the et,hyl nitrite with excess of an acid solution of ferrous sulphate, and then rendering the liquid alkaline with potash. The nlliaceous odour which we had previously observed (Chem. News, 56, 132) whenever nitroethane is reduced with ferrous hydroxide was quite distinct, and by distilling the liquid into diluted hydrochloric acid, and evaporating the distillate to dryness, the hydrochloride of a base was obtained. This was extracted with absolute alcohol and the alcoholic liquid precipitated with ether to remove ammonium chloride, after which the platinochloride was produced in the usual manner and analysed ; it contained 39.2 per cent. of platinum, and was thus proved to be ethylamine platinochloride. Between 40" and 80"' a considerable quantity of liquid distilled ; Che greater part was condensed in the first bulb, a little, however, was found in the second bulb, and this boiled at 17-18", con- sisting almost entirely of ethyl nitrite. Above 80" more liquid distilled and was separately collected. The fraction obtained between 40" and 80" was redistilled; at 16-17" ethyl nitrite passed over, View Article Online 136 THE ALLEGED EXISTENCE OF A SECOND NITROETHANE.
between 18" and 30" the greater part distilled, a third fraction was collected between 30" and loo", and a fourth above 100". From the sub- joined table of results, arranged for convenience in the form of a tree, it will be seen that each of these fractions when redist
Table showing the Results of the Fractional Distillation of the Liquid produced by the Interaction at O", of Ethyl Iodide and Xilver Kitrite. Downloaded by University of Rochester on 12/04/2013 22:39:19. Published on 01 January 1888 http://pubs.rsc.org | doi:10.1039/CT8885300134
* Contained both ethyl nitrite and nitroethane. t Ethyl nitrite. $ Nitroethane. View Article Online BISMUTH IODIDE AND BISMUTH FLUORIDE. 137 and when two figures are given in the table the first is to be regarded as approximate only. We could discover no liquid which boiled con- stantly at 29" and 30"; the fraction obtained at this temperature be- haved both physically and chemically as a solution of ethyl nitrite in nitroethane. The alcohol in the wash-bottles attached to the bulb- condensers was renewed after each distillation, and when tested, every specimen contained more or less ethyl nitrite which had escaped con- densation. It was also noticed that when the original mixture was distilled some nitric oxide escaped, and later distillates contained a little acetic acid. We are justified in concluding from these results that the so- called '' second nitroethane '' is indistinguishable from a mixture, or solution, of the two known isomerides of the formula C2H,N02. Downloaded by University of Rochester on 12/04/2013 22:39:19. Published on 01 January 1888 http://pubs.rsc.org | doi:10.1039/CT8885300134