| Material Notes |
Aniline is a weak base. Aromatic amines such as aniline are, in general, much weaker bases than aliphatic amines. Aniline reacts with strong acids to form anilinium (or phenylammonium) ion (C6H5-NH3+). The sulfate forms beautiful white plates. Although aniline is weakly basic, it precipitates zinc, aluminium, and ferric salts, and, on warming, expels ammonia from its salts. The weak basicity is due to a negative inductive effect as the lone pair on the nitrogen is partially delocalised into the pi system of the benzene ring.; Aniline is an organic chemical compound, specifically a primary aromatic amine. It consists of a benzene ring attached to an amino group. Aniline is oily and, although colorless, it can be slowly oxidized and resinified in air to form impurities which can give it a red-brown tint. Its boiling point is 184 degree centigrade and its melting point is -6 degree centegrade. It is a liquid at room temperature. Like most volatile amines, it possesses a somewhat unpleasant odour of rotten fish, and also has a burning aromatic taste; Aniline was first isolated from the destructive distillation of indigo in 1826 by Otto Unverdorben , who named it crystalline. In 1834, Friedrich Runge (Pogg. 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. 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 n?la, dark-blue, and n?l?, the indigo plant. About the same time N. N. Zinin found that, on reducing nitrobenzene, a base was formed, which he named benzidam. 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.; Aniline, phenylamine or aminobenzene is an organic compound with the formula C6H7N. It is the simplest and one of the most important aromatic amines, being used as a precursor to more complex chemicals. Its main application is in the manufacture of polyurethane. 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. It ignites readily, burning with a smoky flame.; Like phenols, aniline derivatives are highly susceptible to electrophilic substitution reactions. For example, reaction of aniline with sulfuric acid at 180 �C produces sulfanilic acid, NH2C6H4SO3H, which can be converted to sulfanilamide. Sulfanilamide is one of the sulfa drugs that were widely used as antibacterials in the early 20th century.; The great commercial value of aniline was due to the readiness with which it yields, directly or indirectly, dyestuffs. The discovery of mauve in 1856 by William Henry Perkin was the first of a series of an enormous range of dyestuffs, such as fuchsine, safranine and induline. 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).; it is a highly acrid poison. It ignites readily, burning with a large smoky flame. Aniline reacts with strong acids to form salts containing the anilinium (or phenylammonium) ion (C6H5-NH3+), and reacts with acyl halides (such as acetyl chloride (ethanoyl chloride), CH3COCl) to form amides. The amides formed from aniline are sometimes called anilides, for example CH3-CO-NH-C6H5 is acetanilide, for which the modern name is N-phenyl ethanamide. Like phenols, aniline derivatives are highly reactive in electrophilic substitution reactions. For example, sulfonation of aniline produces sulfanilic acid, which can be converted to sulfanilamide. Sulfanilamide is one of the sulfa drugs which were widely used as antibacterial in the early 20th century. Aniline was first isolated from the destructive distillation of indigo in 1826 by Otto Unverdorben. In 1834, Friedrich Runge isolated from coal tar a substance which produced a beautiful blue color on treatment with chloride of lime; this he named kyanol or cyanol. 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, dark-blue. |