Azoxybenzene

Azoxybenzene
Names
	Preferred IUPAC name Diphenyldiazene oxide
	Other names Azoxybenzene; 1-Oxo-1,2-diphenyl-1λ5-diazene; (Diphenyldiazeniumyl)oxidanide; (Z)-1,2-Diphenyldiazene 1-oxide; [(Z)-Phenyl-NNO-azoxy]benzene; Fenazox
Identifiers
CAS Number	495-48-7 ;
3D model (JSmol)	Interactive image;
Beilstein Reference	743984
ChEBI	CHEBI:51865;
ChEMBL	ChEMBL1442921;
ChemSpider	10446022;
ECHA InfoCard	100.007.094
EC Number	207-802-1;
PubChem CID	10316;
UNII	X2K99TM19Q ;
CompTox Dashboard (EPA)	DTXSID0024555 ;
	InChI InChI=1S/C12H10N2O/c15-14(12-9-5-2-6-10-12)13-11-7-3-1-4-8-11/h1-10H Key: GAUZCKBSTZFWCT-UHFFFAOYSA-N;
	SMILES C1=CC=C(C=C1)N=[N+](C2=CC=CC=C2)[O-];
Properties
Chemical formula	C12H10N2O
Molar mass	198.225 g·mol−1
Appearance	yellow solid
Density	1.318 g/cm3
Melting point	35.5–36.5 °C (95.9–97.7 °F; 308.6–309.6 K)
Hazards
	GHS labelling:[1]
Pictograms
Signal word	Warning
Hazard statements	H302, H332
Precautionary statements	P261, P264, P270, P271, P301+P317, P304+P340, P317, P330, P501
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

Azoxybenzene is organic compound with the formula C₆H₅N(O)NC₆H₅. It is a yellow, low-melting solid.^[2] The molecule has a planar C₂N₂O core. The N-N and N-O bond lengths are nearly the same at 1.23 Å.^[3]

Preparation

It can be prepared by partial reduction of nitrobenzene. This reaction is proposed to proceed via the intermediacy of phenylhydroxylamine and nitrosobenzene:^[2]

PhNHOH + PhNO → PhN(O)NPh + H₂O

Another option is the oxidation of aniline by hydrogen peroxide, in acetonitrile at 50 °C. In this reaction, the pH should be kept around 8, to activate the hydrogen peroxide and avoid too much oxygen evolution at the same time. First, the acetonitrile is oxidized, forming an imine hydroperoxide. Then, this intermediate oxidizes the aniline to azoxybenzene. ^[4]

CH₃CN + H₂O₂ → [CH₃C(OOH)=NH]

2 PhNH₂ + 3 [CH₃C(OOH)=NH] → PhN(O)NPh + 3 CH₃C(O)NH₂ + 2 H₂O

PhNO2 + Na₃AsO₃/NaOH→ Ph−N⁺O⁻=N-Ph

References

^ ^a ^b ^c ^d Nomenclature of Organic Chemistry: IUPAC Recommendations and Preferred Names 2013 (Blue Book). Cambridge: The Royal Society of Chemistry. 2014. p. 1009. doi:10.1039/9781849733069-00648. ISBN 978-0-85404-182-4.
^ ^a ^b H. E. Bigelow; Albert Palmer (1931). "Azoxybenzene". Organic Syntheses. 11: 16. doi:10.15227/orgsyn.011.0016.
^ S. P. G. Martínez; S. Bernès (2007). "trans-Diphenyldiazene Oxide". Acta Crystallographica Section E. 63 (8): o3639. doi:10.1107/S1600536807035787.
^ George B. Payne; Philip H. Deming; Paul H. Williams (1961). "Reactions of Hydrogen Peroxide. VII. Alkali-Catalyzed Epoxidation and Oxidation Using a Nitrile as Co-reactant". The Journal of Organic Chemistry. 26 (3): 659-663. doi:10.1021/jo01062a004.

[iupac2013-1] Nomenclature of Organic Chemistry: IUPAC Recommendations and Preferred Names 2013 (Blue Book). Cambridge: The Royal Society of Chemistry. 2014. p. 1009. doi:10.1039/9781849733069-00648. ISBN 978-0-85404-182-4.

[OS-2] H. E. Bigelow; Albert Palmer (1931). "Azoxybenzene". Organic Syntheses. 11: 16. doi:10.15227/orgsyn.011.0016.

[3] S. P. G. Martínez; S. Bernès (2007). "trans-Diphenyldiazene Oxide". Acta Crystallographica Section E. 63 (8): o3639. doi:10.1107/S1600536807035787.

[4] George B. Payne; Philip H. Deming; Paul H. Williams (1961). "Reactions of Hydrogen Peroxide. VII. Alkali-Catalyzed Epoxidation and Oxidation Using a Nitrile as Co-reactant". The Journal of Organic Chemistry. 26 (3): 659-663. doi:10.1021/jo01062a004.

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