Aniline,CAS 62-53-3

Aniline,C6H5NH2, is slightly soluble in water,miscible in alcohol and ether,and turns yellow to brown in air. Aniline may be made(1) by the reduction, with iron or tin in HCI, of nitrobenzene, and(2) by the amination of chlorobenzene by heating with ammonia to a high temperature corresponding to a pressure of over 200 atmospheres in the presence of a catalyst(a mixture of cuprous chlorideandoxide).Aniline is the end point of reduction of most mononitrogen substituted benzene nuclei,as nitro ben

Aniline Use and Manufacturing
Methods of Manufacturing
1. The old process is iron powder reduction method: reduction of nitrobenzene with iron powder, neutralize reaction liquid after washing and distillation to be finished.
2. Nitrobenzene hydrogenation reduction method: Nitrobenzene in the presence of copper catalyst in the fluidized bed reactor for gas-phase hydrogenation reduction, the reaction product by condensation, vacuum distillation to get the product.
3. Nitrobenzene catalytic hydrogenation: usually used catalyst for the Cu-SiO2, the catalyst selectivity, can be successfully reduced nitrobenzene into aniline, not easy to produce benzene nucleus hydrogenation. The reaction is carried out in a fluidized bed reactor, the hydrogen is purified and heated to 350-400℃ by a heater, and then enters the evaporator. At the same time, the nitrobenzene enters the evaporator from the high-level tank, contacts the hot hydrogen gas, And overheated to 180 ~ 223℃, the mixed gas from the bottom of the fluidized bed into the fluidized bed loaded on silica gel on the catalyst in contact with the reaction, the resulting crude aniline and water vapor from the top of the bed. Crude aniline by the condenser cooling, separation, and then by distillation of finished aniline. Now the production of aniline has been achieved a continuous reduction reaction in the atmospheric reflux under boiling conditions, to achieve a small equipment large-scale production. Purification method: aniline according to different preparation methods may contain nitrobenzene, toluidine, benzene, sulfide and other impurities. If aniline dissolved in dilute hydrochloric acid to be colorless and transparent liquid, then generally do not contain hydrocarbons and nitrobenzene. When aniline is dissolved in dilute hydrochloric acid or dilute sulfuric acid, if there is an insoluble matter, it is distilled off by steam distillation, and sodium hydroxide is added to the residue to make basic, and aniline can be obtained by steam distillation again. The distilled aniline is dried with solid sodium hydroxide, and the zinc powder is boiled and refluxed, followed by distillation. Dried with solid sodium hydroxide, and then distilled under reduced pressure in a nitrogen stream to obtain a high-purity product. Aniline can also be converted into its derivatives, such as aniline hydrochloride, acetanilide, and then recrystallization refining.
4. Nitrobenzene, ferrous chloride solution (or ammonium chloride solution) and broken iron powder into the reactor, stirring constantly, the get it by reduct reaction. Or by hydrogen reduction of nitrobenzene.
5. Direct access to industrial aniline as raw materials in nitrogen atmosphere, the same distillation can also be finished reagent. The finished product shall be stored in a sealed brown bottle. In order to prepare chromatographic pure aniline, nitrogen can be used as the carrier gas, and the industrial aniline is injected into the preparative gas chromatograph equipped with Apiezon L or SE30 / white diatomite stationary phase column. The main peak component is separated and collected, Sealed in a vial.
6. Nitrobenzene by catalytic hydrogenation reduction or reduction with iron powder: the resulting aniline with oxalic acid reaction into aniline oxalate, and then purified by alkali treatment, and then in nitrogen atmosphere by distillation to collect 183 ~ 185 ℃ Interstices.
7. Phenol Amination: in the presence of acidic alumina catalyst, with phenol and ammonia at 370 ℃ and 1.6MPa pressure reaction. The raw material of the process is easy to obtain, the production method is simple, the catalyst is inexpensive, the product quality is good, and no gas or large amount of water causing air pollution is produced. The phenol conversion is more than 99% and the yield of aniline is more than 96%. Catalyst stability, no regeneration, but also a diphenylamine production. Therefore, this method is suitable for large-scale continuous production and can produce diphenylamine according to need. But the cost of phenol by the impact of phenol in the supply of adequate and inexpensive, and requires a high quality aniline, less investment when using this law.

Uses
Aniline is a toxic organic compound with the formula C6H5NH2. Consisting of a phenyl group attached to an amino group, aniline is the prototypical aromatic amine. Its main use is in the manufacture of precursors to polyurethane and other industrial chemicals. Like most volatile amines, it possesses the odor of rotten fish. It ignites readily, burning with a smoky flame characteristic of aromatic compounds.