Search results
Results from the WOW.Com Content Network
The reduction of nitroaromatics is conducted on an industrial scale. [1] Many methods exist, such as: Catalytic hydrogenation using: Raney nickel [2] or palladium-on-carbon, [3] [4] [5] platinum(IV) oxide, or Urushibara nickel. [6] Iron in acidic media. [7] [8] [9] Sodium hydrosulfite [10] Sodium sulfide (or hydrogen sulfide and base ...
o-Nitrophenol (2-nitrophenol; OH and NO 2 groups are neighboring, a yellow solid. m-Nitrophenol (3-nitrophenol, CAS number: 554-84-7), a yellow solid (m.p. 97 °C) and precursor to the drug mesalazine (5-aminosalicylic acid). It can be prepared by nitration of aniline followed by replacement of the amino group via its diazonium derivative. [2]
Azo dyes are also prepared by the condensation of nitroaromatics with anilines followed by reduction of the resulting azoxy intermediate: ArNO 2 + Ar'NH 2 → ArN(O)=NAr' + H 2 O ArN(O)=NAr' + C 6 H 12 O 6 → ArN=NAr' + C 6 H 10 O 6 + H 2 O. For textile dying, a typical nitro coupling partner would be disodium 4,4′-dinitrostilbene-2,2 ...
Free radical nitration of alkanes. [4] The reaction produces fragments from the parent alkane, creating a diverse mixture of products; for instance, nitromethane, nitroethane, 1-nitropropane, and 2-nitropropane are produced by treating propane with nitric acid in the gas phase (e.g. 350–450 °C and 8–12 atm).
A solution of 4-nitrophenol appears colorless below pH 5.4 and yellow above pH 7.5. [3] This color-changing property makes this compound useful as a pH indicator. The yellow color of the 4-nitrophenolate form (or 4-nitrophenoxide) is due to a maximum of absorbance at 405 nm (ε = 18.3 to 18.4 mM −1 cm −1 in strong alkali). [4]
In organic chemistry, an azo coupling is an reaction between a diazonium compound (R−N≡N +) and another aromatic compound that produces an azo compound (R−N=N−R’).In this electrophilic aromatic substitution reaction, the aryldiazonium cation is the electrophile, and the activated carbon (usually from an arene, which is called coupling agent), serves as a nucleophile.
Azobenzene is a photoswitchable chemical compound composed of two phenyl rings linked by a N=N double bond.It is the simplest example of an aryl azo compound.The term 'azobenzene' or simply 'azo' is often used to refer to a wide class of similar compounds.
ArN(O)=NAr′ + C 6 H 12 O 6 → ArN=NAr′ + C 6 H 10 O 6 + H 2 O. For textile dying, a typical nitro coupling partner would be disodium 4,4′-dinitrostilbene-2,2′-disulfonate. Typical aniline partners are shown below. Since anilines are prepared from nitro compounds, some azo dyes are produced by partial reduction of aromatic nitro ...