Page:Encyclopædia Britannica, Ninth Edition, v. 17.djvu/563

Rh NITROGEN 519 must be understood liere to include glycerin, sugar, mannite, cellu lose, and many other OH-compoun.ls not usually culled alcohols (in these the group N0. 2 . stands where the OH was in the original substance) ; and (2) nitro-bodies proper, in which the N0 2 -group has taken the place of an H which was combined directly with carbon. An example is the nitrobenzol, C 6 H 5 (N0 2 ), produced from benzol, C B H 5. H. When such a (true) nitro-hody is treated with nascent hydrogen, the N0 2 as a rule goes out and is replaced by an amidogen XH, ; thus C 6 H 5 (NO,) becomes C B H 3 (NJ1. ! ), amido-benzol or aniline. The nitric esters, in the circumstances, yield up their NO., as ammonia. For other metallic nitrates, see under the respective metals. For nitric esters, see MKTHYL, GUN-COTTON, and NITROGLYCERIN. For nitric anhydride (N 2 5 ), peroxide of nitrogen (N 2 4 ), nitrous acid (N 2 O 3 ), nitric oxide (NO), nitrous oxide (N 2 0, laughing-gas), also chloride of nitrosyle (aqua rcgia), see CHEMISTRY, p. 511 sq. Nitrogenous Carbon Compounds. Of this very numerous family we can only name a few of the more important groups and explain their genetic relations. Cyanides, compounds of the radical (NC), 1 are important to us here chiefly as a link between the two elements on the one hand and nitrogenous organic bodies proper on the other. Hydrocyanic acid, NCH, can be produced synthetically in a number of ways ; we may, for instance, synthesize cyanide of barium, BaN 2 C 2, as shown above, and decompose it by sulphuric acid. A more direct method is to first combine carbon with hydrogen into acetylene and then to subject a mixture of this and nitrogen gas to a spark-current, when hydrocyanic acid is produced, thus: C 2 H 2 + N 2 = 2HNC. Alkylamines. When hydrogen is generated within an acidified solution of hydrocyanic acid by means of zinc, the cyanide, by taking over four atoms of hydrogen, passes into (a salt of) methyl- amine, NCH + 4H = NH 2 .CH 3. It is explained under METHYL how this base may be utilized for the production of methyl- alcohol, and thus, indirectly, of iodide of methyl and of acetonitrile (pseudo-cyanide of methyl, NC . CH ;J ). This shows the possibility of producing from hydrocyanic acid, in the first instance di- and tri-methylamine, and, more indirectly, the whole series of alkyla- mines (NH 2 R, NHR^,, NR 3 ; where R = CH 3, CH 3 + CH 2 = C 2 H 5 , C. 2 H 5 + CH 2 = C 3 H 7 , &c. ). Closely allied to these alkylamines are the diamines, derived from the bromides of the defines, C n H 2ll, as the former are from those, or the iodides, of the alcohol-radicals CH 3, C 2 H 5 , &c. To ethylamine, for instance, corresponds ethy- lene-diamine, C 2 H 4 (NH 2 ) 2. Acid-amides are bodies related to acids, as alkylamines are to alcohols. Thus, for instance, C 2 H 5 NH 2 corresponds to [CH 3 .CO]NH 2. Ethyiamine. Acetamide. Polybasic acids form each a series of amides. Thus succinic acid, C 2 H 4 (COOH) 2, forms two amides, viz., C H / COOH ,nd C H V^S* 1 L 2 H 4 Succinamic acid. Succinamide. All acid-amides are the anhydrides of corresponding ammonia salts, and can be produced from these by actual dehydration ; there is no need of explaining by an equation what is so clearly seen in the formulpe. The two succinamides just named, and all analogous &quot;amides,&quot; are susceptible of further lehydration: thus succinamic acid, C 2 H^&amp;lt; by losing the bracketed OH and H becomes X succinimid, . ., and succinamide, C H, = ^= , 4 C|0|N|H,| similarly becomes succino-nitrile, Acid-amides must not be mixed up with amido-acids. Amido-acids have their (NH 2 ) within the specific, not in the generic, radical. Thus, acetic acid, CH 3 COOH, by chlorination, becomes chloracetic acid, CH 2 C1. COOH, and this chloro-acid again gives up its chlorine to ammonia and to caustic potash, and receives back NH 2 in the one case and OH in the other, becoming CH 2 (NH 2 ). COOH and CH 2 (OH). COOH Amido-acetic acid. Oxy-acetic or glycollic acid. respectively. The latter forms an amide, CH 2 (OH)CO. NH 2, as acetic acid does, and this amide, as is easily seen, is isomeric with amido-acetic acid, either being oxy-acetic minus OH plus NH. 2 ; but 1 See CHEMISTRY. Some of the more important cyanides will be discussed under PRUSSIC ACID. the two differ widely from each other. The amide, when treated with aqueous potash, yields ammonia and glycollate of potash, the amido-acid water and amido-acetate of potash. The substance asparagine, which is contained in so many vegetable juices, and otten appears as a decomposition product of albumenoids, is an amide and an amido-acid in one, being amido-succinamic acid. PH COOH p TT .. I CO. XII., ^2^4 COOH ^ u *a n -J I CO. OH &quot; Succinic acid. Asparagine. With the so-called aromatic bodies a very general method for producing amido-bodies is first to prepare a nitre-body and then reduce it by nascent hydrogen. Thus, for instance, we can convert nitrobenzol, C 6 H 5 .NO.,, above referred to, into amido-benzol, C 6 H g. NH,. We shall use this body as an example to explain the general mode of formation of a most interesting group of nitro genous compounds which at present play a great part in the colour industry. Diazo-bodies. All NH. 2 compounds, when treated with water and nitrous acid, virtually NO. OH= 2 (N 2 3 + H,0), yield the corresponding hydroxyl (OH) compounds, with joint elimination of the nitrogen of substance and reagent as nitrogen gas. Thus we have C 6 H 5 NH a + OH. NO = C.Hg. OH + H,0 + N 2. Aniline. &quot; Phenol. This is quite a general reaction ; but in the case of aromatic amines the reaction takes a different turn, if, instead of the free amine, we use one of its salts, and, in a relative sense at least, exclude water as a medium. In the case of nitrate of aniline, for instance, the two atoms of oxygen in the nitrous acid combine with all the hydrogen of the generic radicals, while all the rest unites into diazo-benzol : HN0 3. C 6 H 5. NH, + NO. OH = 2H 2 + C,,H 5 N=N N0 3. Nitrate of diazo-benzol. And similarly in similar cases. Diazo-benzol has a great tendency to give off the nitrogen gas N 2 which is visible in its formula. We need only treat it with water and it yields what nitrous acid water would have given at once : C fi H 5 N=N N0 3 + H. OH = HN0 3 + N, + C 6 H 5. OH. There is something between the nitrates of amido- and of diazo- benzol, which, it is true, has only a theoretical existence in this case, but can be realized in other analogous cases. Nitroso -ladies. Ethylamine, under the action of water and nitrous acid, yields alcohol, C 2 H S .OH, as aniline yields phenol, and other monamines yield their alcohols. With diethylamine this reaction cannot take place ; what does take place is that the NO of the nitrous acid expels and takes the place of the one loose II in the amine, and forms nitroso-diethyline : N. H. (C 2 H 5 ) 2 + NO. OH = H. OH + N. (NO). (C 2 H 5 ) 2. Xitroso-diet byline. H ydrazines. This nitroso-diethyline is a liquid boiling at 177, devoid of alkaline properties. When treated with zinc-dust and acetic acid it yields a basic substance diethyl-hydrazine, which contains NH 2 in lieu of the NO of the nitroso-body. N. (NO)(C 2 H,), N. (XH 2 )(C 2 H B ) 3. Nitroso-diethyline. Diethyl-hydrazine. This hydrazine is only one of a large genus, representatives of which are also obtainable from diazo-bodies by nascent hydrogen. Example C B H 8 N N (HS0 4 ) + 4H H 2 S0 4 + CH 5 XH. (NH 2 ). Sulphate of diazo-benzol. Phenyl-hydrazme. Urcids are a class of bodies which are related to urea as amido- bodies are to ammonia. Thus correspond to NH 3 NH 3 (NHo) (2XH 2 )&quot; co Urea. Urea radicals. We satisfy ourselves with quoting two ureids derived from oxalic acid C &amp;lt;^9^r Just as we have two ammonia derivatives, 2 Oxamic acid, so there exist two urea-derivatives Oxaluric acid. &quot; 1 arabanic acid. The urea radicals are enclosed in square brackets. These are two examples of a large family of bodies interesting on account of then- close relationship to uric acid, a constant component of urine. Creatine is a crystalline base which was discovered by Lieb.g