REDUCTION OF ALIPHATIC NITRITES TO AMINES. 899 LLXXV 1.-Reduction of Aliphatic Nitrites to Amines. By PANCHANAN NEOGI and TARINI CHARAN CHOWDHURI. NEOGI a.nd Chowdhuri have shown (T. 1916 109 701) that aliphatic nitrites are partly converted into the corresponding nitro-compounds by the action of heat. The conversion com-mences at about looo and the best results ar0 obtained a t 125-130°. If however the temperature is further raised, secondary reactions take place and in addition to nitro-com-pounds aldehydes and acids are Iormed. By the reduction of aliphatic nitrites in solution alcohol and hydroxylamine or ammonia are obtained but as the nitrites are partly converted into nitro-compounds on heating it follows that on reducing them a t a higher temperature amines should be pro-duced in addition t o ammonia.Gaudion has shown (Ann. Chim. Phys. 1912 [viiil 25 125) that amines are obtained by the reduction of aliphatic nitrites with heated finely divided nickel or copper. The temperature employed by him however was very high namely above 220° in the case of nickel and above 300° in the case of copper temperatures at which the nitrites decom-pose giving secondary products. He therefore obtained a mix-ture of mono- di- and tri-alkylamines in the reaction. We have, V O L CXI. N 900 NEOQI AND CHOWDHURI : however made experiments at as low a temperature as 100-130°, and have been able to show that the corresponding monoalkyl-amine alone is obtained thus conclusively proving that the resultant amine is the direct product of reduction of the nitro-compound best formed a t 125-130° as previously shown by us.That nitro-compounds are reduced to amines when a mixture of hydrogen and the nitro-compounds is passed over heated nickel has already been shown by Sabatier and Senderens (Cornpit. rend., 1902 135 226). E X P E R I M E N T A L . A slow stream of pure hydrogen was passed through a flask containing the aliphatic nitrite and the mixture of hydrogen and nitrite vapour then passed into a combustion tube about 90 cm. in length filled with reduced nickel and heated in an asbestos box pjrovided with a thermometer. The air was first expelled by the current of hydrogen and then the mixture of the two gases allowed to pass into the tube. To the other end of the tube was attached a dry test-tube immersed in cold water and connected in its turn with two Erlenmeyer flasks containing dilute hydro-chloric acid.Liquid products of reduction such as alcohols and part of the liquid amines collect in the test-tube whilst the vapour of the escaping amines especially in the case of the lower members and ammonia are arrested in the hydrochloric acid flasks. The liquid in the test-tube which gave the pungent fishy odour of the amines was neutralised with hydrochloric acid and the alcohol distilled off. The alcohol was recognised by its odour and identified by determining the boiling point of its acetate. The hydrochloride of the amine and ammonia in the Erlen-meyer flasks and in the test-tube after distilling off the alcohol was evaporated t o dryness.The amine hydrochloride was separated from ammonium chloride by repeated exhaustion with small quantities of absolute alcohol and ether. Besides recog-nising the amines by Hofmann’s carbylamine reaction and other characteristic tests they were identified quantitatively by pre-paring their platinichlorides. Analysis of these showed that monoalkyl- and not di- or tri-alkyl-amines were formed. One point is important in the preparation of the amine platini-chlorides in the presence of ammonia. It is known that even on repeated exhaustion of a mixture of amine hydrochloride and ammonium chloride with alcohol and ether the amine hydro-chloride is not obtained free from ammonium chloride. On the addition of platinic chloride however to a moderately dilut REDUCTION OF ALIPHATIC NITRITES TO AMINES.90 1 solution of the salts the precipitate which is first produced con-tains all the remaining ammonium chloride together with a little amine hydrochloride If now platinic chloride is added t o the filtrate and the solution concentrated i f necessary shining, yellow crystals are formed consisting solely of the amine platini-chloride. The use of reduced nickel in the powder form as employed by Sabatier and Senderens was not satisfactory. The powder forms a layer inside the glass tube and evidently does not present a sufficiently large surface of contact for the action of ths gases. We tilerefore prepared nickelised ash estos by first soaking asbestos fibre in a concentrated solution of nickel nitrate then drying and heating it in the blow-pipe in a large nickel basin in order to convert the nitrate into the oxide.The glass tube was then filled with the asbestos impregnated with nickel oxide placed in an inclined position and heated a t about 300° in a current of hydrogen when the oxide was reduced t o metallic nickel. The nickeiised asbestos with which a tube can be fully packed is strongly recommended whenever reduced nickel is necessary for work with gases as it presents a very large surface for the react-ing gases with the use of a comparatively small quantity of nickel. When once prepared the nickelised asbestos may be used over and over again. The experiments here described were also repeated with reduced iron but the results were much less satisfactory. isoAniylamine from isoAmyl Xitrite.The products from six experiments in each of which 4 C.C. of The temperature employed the nitrite were used were united. was 1 23-130° : Amine hydrochloride = 1 * 6 grams Ammonium chloride = 3.4 ,, Analysis of the platinichloride of the amine gave Pt = 33.61, The acetate of the alcohol was prepared and identified as iso-whereas isoamylamine platinichloride requires Pt = 33-39 per cent. amyl acetate by its boiling point (137-138O). isoButylamine from isoButyl Nitrite. Seven experiments were performed a t 125-130° using 4 to 5 C.C. of nitrite in each case: Amine hydrochloride = 1.9 grams. Ammonium chloride = 3.2 ,, " 90.2 REDUCTION OF ALIPHATIC NITRITES TO AMINES. Analysis of the platinichloride gave Pt = 35.23 ; calc. Pt = 35.07 isoButyl acetate was prepared from the alcohol and identified per cent.by its boiling point (116-117°). N-Propylarnine from n-Pro pyl Nitrite. Six experiments were made a t 130° using the same quantities as in the previous experiments: Amine hydrochloride= 1.3 grams. Ammonium chloride = 2.9 ,, Analysis of the platinichloride gave Pt = 37.10 ; calc. Pt = 36-93 The acetate of the alcohol boiled a t 10Zo showing that the per cent. alcohol was n-propyl alcohol. Etkylamine from Ethyl Nitrite. As ethyl nitrite is gaseous a t the ordinary temperature it was dissolved in paraffin oil and a 25 per cent. solution was used As the nitrite is very volatile even in solutibn much escaped with-out reduction. As a result of six experiments using 5 C.C. of the solution each time ethylamine hydrochloride (0.62 gram) and ammonium chloride (3.2 grams) were obtained. Analysis of the platini-chloride gave Pt = 39-23 ; calc. Pt = 39.00 per cent. Ethyl alcohol was detected by the iodoform morphine and other tests . Methylamine front Methyl Nitrite. Methyl nitrite was prepared according to the directions given in our previous paper (loc. cit.) and dissolved in paraffin oil. Much of the nitrite escaped reduction owing t o its volatility. About 0.10 gram of the amine hydrochloride was obtained as the result of six experiments. Owing to the low yield of the amine salt and to the presence of much ammonium chloride analysis of the small quantity of the platinichloride did not give good results. Methyl alcohol was recognised by the formic acid morphine, and other tests. CHEMICAL LABORATORY, GOVERNMENT COLLEGE, RAJSHAHI BENOAL INDIA. [Received May 4th 1917.