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4-Aminophenol (or para-aminophenol or p-aminophenol) is an organic compound with the formula H 2 NC 6 H 4 OH. Typically available as a white powder, [ 3 ] it is commonly used as a developer for black-and-white film , marketed under the name Rodinal .
The Gmelin rare earths handbook lists 1522 °C and 1550 °C as two melting points given in the literature, the most recent reference [Handbook on the chemistry and physics of rare earths, vol.12 (1989)] is given with 1529 °C.
The three aminophenol isomers: Left: 2-Aminophenol (o-aminophenol) Center: 3-Aminophenol (m-aminophenol) Right: 4-Aminophenol (p-aminophenol) Aminophenol may refer to any of three isomeric chemical compounds: 2-Aminophenol; 3-Aminophenol; 4-Aminophenol; They are simultaneously an aniline and a phenol
The presence of the aromatic ring also draws electrons away from the ethereal oxygen, making the hydrolysis of a phenol ether significantly more difficult than that of an alkyl ether. [5] The ethereal oxygen must be significantly nucleophilic in order for the ether to undergo acid-catalyzed hydrolysis.
The classical methods for the production of paracetamol involve the acetylation of 4-aminophenol with acetic anhydride as the last step. They differ in how 4-aminophenol is prepared. In one method, nitration of phenol with nitric acid affords 4-nitrophenol, which is reduced to 4-aminophenol by hydrogenation over Raney nickel.
The melting point (or, rarely, liquefaction point) of a substance is the temperature at which it changes state from solid to liquid. At the melting point the solid and liquid phase exist in equilibrium. The melting point of a substance depends on pressure and is usually specified at a standard pressure such as 1 atmosphere or 100 kPa.
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]
3-Aminophenol is an organic compound with formula C 6 H 4 (NH 2)(OH). It is an aromatic amine and a phenol . It is the meta isomer of 2-aminophenol and 4-aminophenol .