Phenylhydroxylamine

Phenylhydroxylamine

Names
IUPAC name N-phenylhydroxylamine
Other names beta-henylhydroxylamine; N-hydroxyaniline; phenylhydroxylamine; N-hydroxybenzeneamine; hydroxylaminobenzene
Identifiers
CAS Registry Number	100-65-2 N
Jmol-3D images	Image
SMILES ONC1=CC=CC=C1
Properties
Chemical formula	C6H7NO
Molar mass	109.1274 g/mol
Appearance	yellow needles
Melting point	80 to 81 °C (176 to 178 °F; 353 to 354 K)
Related compounds
Related compounds	hydroxylamine, nitrosobenzene
Except where noted otherwise, data is 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, is C₆H₅ONH₂.

Preparation and derivatives

This compound can be prepared by the reduction of C₆H₅NO₂ with zinc in the presence of NH₄Cl followed by crystallization as yellowish needles from salt-saturated water.^[1][2] Alternatively, it can be prepared by transfer hydrogenation of C₆H₅NO₂ using hydrazine as an H₂ source over a rhodium catalyst.^[3] The product can be purified from contaminating NaCl by extraction into benzene followed by precipitation with petroleum ether. C₆H₅NHOH 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

References