Wiley-Interscience, Wiley & Sons, Inc. Hoboken, NJ. The discovery of mauve in 1856 by William Henry Perkin was the first of a series of dyestuffs that are now to be numbered by hundreds. Phys. To use all the functions on Chemie.DE please activate JavaScript. Your browser does not support JavaScript. Monomethyl aniline boils at 193-195 °C, dimethyl aniline at 192 °C. Aniline combines directly with alkyl iodides to form secondary and tertiary amines. You may need to download version 2.0 now from the Chrome Web Store. Primary amines with three or four carbon atoms are liquids at room temperature whereas higher ones are solids. Soc. The oxidation of aniline has been carefully investigated. Aniline is colourless, it slowly oxidizes and resinifies in air, giving a red-brown tint to aged samples. The K and B bands arise from π to π* transitions as a result of the a group containing multiple bond being attached to the benzene ring. Aniline absorbs in the K (220 - 250 nm) and the B (250 - 290 nm) bands exhibited by benzenoid compounds. About the same time N. N. Zinin found that, on reducing nitrobenzene, a base was formed, which he named benzidam. To use all functions of this page, please activate cookies in your browser. Hazardous Substances Data Bank (HSDB) Decomposes slowly in water to form acetic acid. If you are at an office or shared network, you can ask the network administrator to run a scan across the network looking for misconfigured or infected devices. Kaur, H. Spectroscopy. p-Toluidine, an aniline derivative, can be used in qualitative analysis to prepare carboxylic acid derivatives. In the latter case the anilinium cation is formed and the lone pair is no longer available for conjugation with the benzene ring. The nitrobenzene is then hydrogenated (typically at 200300 0 C) in the presence of metal catalyst. August Wilhelm von Hofmann investigated these variously-prepared substances, and proved them to be identical (1855), and thenceforth they took their place as one body, under the name aniline or phenylamine. Consisting of a phenyl group attached to an amino group, aniline is usually produced in industry in two steps from benzene: First, benzene is nitrated using a concentrated mixture of nitric acid and sulfuric acid at 50 to 60 °C, which gives nitrobenzene. At the present time, the largest market for aniline is preparation of methylene diphenyl diisocyanate (MDI), some 85% of aniline serving this market. Ann., 1834, 31, p. 65; 32, p. 331) isolated from coal tar a substance that produced a beautiful blue colour on treatment with chloride of lime, which he named kyanol or cyanol. Its first industrial-scale use was in the manufacture of mauveine, a purple dye discovered in 1856 by Hofmann's student William Henry Perkin. This article incorporates text from the Encyclopædia Britannica Eleventh Edition, a publication now in the public domain. Performance & security by Cloudflare, Please complete the security check to access. Lewis, R.J. Sr. (ed) Sax's Dangerous Properties of Industrial Materials. Your IP: 116.202.104.140 The oxidation of aniline has been carefully investigated. Its main application is in the manufacture of polyurethane. Some authorities class aniline as a carcinogen, although the IARC lists it in Group 3 (not classifiable as to its carcinogenicity to humans) due to the limited and contradictory data available. It is the simplest and one of the most important aromatic amines, being used as a precursor to more-complex chemicals. Properties Oxidation. Reference should be made to the articles dyeing, fuchsine, safranine, indulines, for more details on this subject. Through these, the -NH2 group of aniline can be conveniently converted to -OH, -CN, or a halide via Sandmeyer reactions. In addition to its use as a precursor to dyestuffs, it is a starting-product for the manufacture of many drugs, such as paracetamol (acetaminophen, Tylenol). [5] The synthetic dye industry grew rapidly as new aniline-based dyes were discovered in the late 1850s and 1860s. Although aniline is weakly basic, it precipitates zinc, aluminium, and ferric salts, and, on warming, expels ammonia from its salts. Table data obtained from CRC Handbook of Chemistry and Physics 44th ed. Sulfanilamide is one of the sulfa drugs that were widely used as antibacterials in the early 20th century. ITII. When dissolved in ethanol, λmax for aniline is 230 nm, but in dilute aqueous acid λmax is 203 nm. Aromatic amines such as aniline are, in general, much weaker bases than aliphatic amines. The NH2 group attached to the benzene ring means that there is a lone pair of electrons that can enter into conjugation with the benzene ring resulting in delocalization in the aniline. Lang, 1928 Lang, H.R. Aniline and other arylamines are generally colourless. The amides formed from aniline are sometimes called anilides, for example CH3-CO-NH-C6H5 is acetanilide. In alkaline solution, azobenzene results, whereas arsenic acid produces the violet-colouring matter violaniline. • Aniline absorbs in the K (220 - 250 nm) and the B (250 - 290 nm) bands exhibited by benzenoid compounds. Boiled with carbon disulfide, it gives sulfocarbanilide (diphenyl thiourea), CS(NHC6H5)2, which may be decomposed into phenyl isothiocyanate, C6H5CNS, and triphenyl guanidine, C6H5N=C(NHC6H5)2. Consequently, the absorption of the molecule shifts to the lower λmax value and behaves like benzene. Categories: Aromatic amines | Dyes | IARC Group 3 carcinogens. Reaction with sulfuric acid at 180°C produces sulfanilic acid, NH2C6H4SO3H. (6) Aniline is soluble in water. It is highly recommend that you seek the Material Safety Datasheet (MSDS) for this chemical from a reliable source and follow its directions. Let us now look at the physical properties of amines in brief. 11th Edition. As an alternative, aniline is also prepared from phenol and ammonia, the phenol being derived from cumene. The NH 2 group attached to the benzene ring means that there is a lone pair of electrons that can enter into conjugation with the benzene ring resulting in delocalization in the aniline. Find out how LUMITOS supports you with online marketing. • Prolonged exposure to the vapour or slight skin exposure over a period of time affects the nervous system and the blood, causing tiredness, loss of appetite, headache, and dizziness.[6]. Aniline and other arylamines are generally colorless, but they get coloured if stored in open due to atmospheric oxidation. Physical Properties Aniline is a colorless oily liquid with a characteristic taste. The lower aliphatic amines are gaseous in nature with a fishy smell. In commerce, three brands of aniline are distinguished--aniline oil for blue, which is pure aniline; aniline oil for red, a mixture of equimolecular quantities of aniline and ortho- and para-toluidines; and aniline oil for safranine, which contains aniline and ortho-toluidine, and is obtained from the distillate (échappés) of the fuchsine fusion. Physical properties of aniline - definition Industrial aniline production involves two steps. First, benzene is nitrated with a concentrated mixture of nitric acid and sulfuric acid at 50 to 60 0 C to yield nitrobenzene. Except where noted otherwise, data relate to standard ambient temperature and pressure. Like most volatile amines, it possesses the somewhat unpleasant odour of rotten fish and also has a burning aromatic taste; it is a highly-acrid poison. Hypochlorous acid gives 4-aminophenol and para-amino diphenylamine. Read what you need to know about our industry portal chemeurope.com. Potassium permanganate in neutral solution oxidizes it to nitrobenzene, in alkaline solution to azobenzene, ammonia and oxalic acid, in acid solution to aniline black. Aniline reacts with carboxylic acids[2] or more readily with acyl chlorides such as acetyl chloride to give amides. It causes headache, drowsiness, cyanosis, and mental confusion, and, in severe cases, can cause convulsions. In 1834, Friedrich Runge (Pogg. © 1997-2020 LUMITOS AG, All rights reserved, https://www.chemeurope.com/en/encyclopedia/Aniline.html, Your browser is not current. If you are on a personal connection, like at home, you can run an anti-virus scan on your device to make sure it is not infected with malware. (1,6) The chemical formula for aniline is C 6 H 7 N and the molecular weight is 93.12 g/mol. Other uses include rubber processing chemicals (9%), herbicides (2%), and dyes and pigments (2%).[3]. Primary amines with three or four carbon atoms are liquids at room temperature whereas higher ones are solids. London, 1933, 45, 194-207. Cloudflare Ray ID: 5f0a75487dc9d0fd Microsoft Internet Explorer 6.0 does not support some functions on Chemie.DE. With an accout for my.chemeurope.com you can always see everything at a glance – and you can configure your own website and individual newsletter. Aniline was first isolated from the destructive distillation of indigo in 1826 by Otto Unverdorben[4] , who named it crystalline. Monomethyl and dimethyl aniline are colourless liquids prepared by heating aniline, aniline hydro-chloride and methyl alcohol in an autoclave at 220 °C. In 1841, C. J. Fritzsche showed that, by treating indigo with caustic potash, it yielded an oil, which he named aniline, from the specific name of one of the indigo-yielding plants, Indigofera anil, anil being derived from the Sanskrit nīla, dark-blue, and nīlā, the indigo plant. , A method for the determination of the specific heats of liquids, and a determination of the specific heats of aniline and benzene over the approximate range 20°C to 50°C, Proc. Fluid Flow Table of Contents Hydraulic and Pneumatic Knowledge Fluid Power Equipment. The sulfate forms beautiful white plates. Toxic and Hazarous Industrial Chemicals Safety Manual. Aniline is a benzenoid compound. Aniline reacts with strong acids to form anilinium (or phenylammonium) ion (C6H5-NH3+). For example, sulfonation of aniline produces sulfanilic acid, which can be converted to sulfanilamide.
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