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Skeletal formula of phenylhydroxylamine
Ball-and-stick model of the phenylhydroxylamine molecule
IUPAC name
Other names
beta-phenylhydroxylamine; N-hydroxyaniline; phenylhydroxylamine; N-hydroxybenzeneamine; hydroxylaminobenzene
3D model (JSmol)
ECHA InfoCard 100.002.614
EC Number 209-711-2
Molar mass 109.1274 g/mol
Appearance yellow needles
Melting point 80 to 81 °C (176 to 178 °F; 353 to 354 K)
-68.2·10−6 cm3/mol
Related compounds
Related compounds
hydroxylamine, nitrosobenzene
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

Phenylhydroxylamine is the organic compound with the formula C6H5NHOH. It is an intermediate in the redox-related pair C6H5NH2 and C6H5NO. Phenylhydroxylamine should not be confused with its isomer α-phenylhydroxylamine or O-phenylhydroxylamine.


This compound can be prepared by the reduction of nitrobenzene with zinc in the presence of NH4Cl followed by crystallization as yellowish needles from salt-saturated water.[1][2] The product can be purified from contaminating NaCl by extraction into benzene followed by precipitation with petroleum ether.

Alternatively, it can be prepared by transfer hydrogenation of nitrobenzene using hydrazine as an H2 source over a rhodium catalyst.[3]


Phenylhydroxylamine is unstable to heating, and in the presence of strong acids easily rearranges to 4-aminophenol. Oxidation of phenylhydroxylamine with dichromate is a useful method of preparation of nitrosobenzene.

The compound condenses with benzaldehyde to form diphenylnitrone, a well-known 1,3-dipole:[4]

C6H5NHOH + C6H5CHO → C6H5N(O)=CHC6H5 + H2O


  1. ^ E. Bamberger “Ueber das Phenylhydroxylamin” Chemische Berichte, volume 27 1548-1557 (1894). E. Bamberger, "Ueber die Reduction der Nitroverbindungen" Chemische Berichte, volume 27 1347-1350 (1894) (first report).
  2. ^ O. Kamm (1941). "Phenylhydroxylamine". Org. Synth. ; Coll. Vol., 1, p. 445 
  3. ^ P. W. Oxley, B. M. Adger, M. J. Sasse, and M. A. Forth (1993). "N-Acetyl-N-Phenylhydroxylamine via Catalytic Transfer Hydrogenation of Nitrobenzene using Hydrazine and Rhodium on Carbon". Org. Synth. ; Coll. Vol., 16, p. 16 
  4. ^ I. Brüning, R. Grashey, H. Hauck, R. Huisgen, H. Seidl (1973). "2,3,5-Triphenylisoxazolidine". Org. Synth. ; Coll. Vol., 5, p. 1124