Search results
Results from the WOW.Com Content Network
Nitrobenzene is prepared by nitration of benzene with a mixture of concentrated sulfuric acid, water, and nitric acid. This mixture is sometimes called "mixed acid." The production of nitrobenzene is one of the most dangerous processes conducted in the chemical industry because of the exothermicity of the reaction (ΔH = −117 kJ/mol). [5] +
The nitration product produced on the largest scale, by far, is nitrobenzene. Many explosives are produced by nitration including trinitrophenol (picric acid), trinitrotoluene (TNT), and trinitroresorcinol (styphnic acid). [3] Another but more specialized method for making aryl–NO 2 group starts from halogenated phenols, is the Zinke nitration.
The reaction was first used by Antoine Béchamp to reduce nitronaphthalene and nitrobenzene to naphthylamine and aniline, respectively. [3] The Béchamp reduction is broadly applicable to aromatic nitro compounds. [4] [5] Aliphatic nitro compounds are however more difficult to reduce, often remaining as the hydroxylamine. Tertiary aliphatic ...
Several methods have been described for the production of aryl hydroxylamines from aryl nitro compounds: Raney nickel and hydrazine at 0-10 °C [15] Electrolytic reduction [16] Zinc metal in aqueous ammonium chloride [17] Catalytic Rhodium on carbon with excess hydrazine monohydrate at room temperature [18]
Main page; Contents; Current events; Random article; About Wikipedia; Contact us; Help; Learn to edit; Community portal; Recent changes; Upload file
Some polymer solutions also have a lower critical solution temperature (LCST) or lower bound to a temperature range of partial miscibility. As shown in the diagram, for polymer solutions the LCST is higher than the UCST, so that there is a temperature interval of complete miscibility, with partial miscibility at both higher and lower temperatures.
Benzidine is prepared in a two step process from nitrobenzene. First, the nitrobenzene is converted to 1,2-diphenylhydrazine , usually using iron powder as the reducing agent. Treatment of this hydrazine with mineral acids induces a rearrangement reaction to 4,4'-benzidine.
The mechanism of the Bamberger rearrangement proceeds from the monoprotonation of N-phenylhydroxylamine 1.N-protonation 2 is favored, but unproductive. O-protonation 3 can form the nitrenium ion 4, which can react with nucleophiles (H 2 O) to form the desired 4-aminophenol 5.