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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]
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]
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 ...
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).
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 ...
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.
Structural formula of nitroso group. In organic chemistry, nitroso refers to a functional group in which the nitric oxide (−N=O) group is attached to an organic moiety.As such, various nitroso groups can be categorized as C-nitroso compounds (e.g., nitrosoalkanes; R−N=O), S-nitroso compounds (nitrosothiols; RS−N=O), N-nitroso compounds (e.g., nitrosamines, RN(−R’)−N=O), and O ...
It is used in addition with triethylamine to activate nitro groups to undergo (C,O) 1,3-dipolar cycloaddition (as opposed to O,O). The nitro group (RCH 2 NO 2) is converted to oxime-like dimers in the reaction: [3] 4 PhNCO + 2 RCH 2 NO 2 → 2(PhNH) 2 CO + 2 CO 2 + (RCNO) 2