Hydrazobenzene → Azobenzene

HRID 2164382

Reaction equation

HRID 2164382 reaction equation
[NH:1]([C:9]1[CH:14]=[CH:13][CH:12]=[CH:11][CH:10]=1)[NH:2][C:3]1[CH:8]=[CH:7][CH:6]=[CH:5][CH:4]=1.[H][H]>[Pd]>[NH2:1][C:9]1[CH:14]=[CH:13][CH:12]=[CH:11][CH:10]=1.[N:1]([C:9]1[CH:10]=[CH:11][CH:12]=[CH:13][CH:14]=1)=[N:2][C:3]1[CH:8]=[CH:7][CH:6]=[CH:5][CH:4]=1

Participants

5

Reactant 2

HCID 31222HydrazobenzeneHCID 178418361HCID 178418361, compound

Product 2

HCID 2272AzobenzeneHCID 6115Aniline

Reagents, catalysts & solvents 1

HCID 23938PalladiumCatalyst

Procedure

It has now been found that the abovementioned disadvantages are avoided when the aryldiazosulfonates are catalytically hydrogenated. There is apparently a prejudice against this means of reduction, since even though a large number of reducing agents have been proposed for this purpose (Houben-Weyl, loc. cit. 180 to 223), catalytic hydrogenation has not been considered, presumably because reducing agents which can convert a nitro group into the amino group cleave aromatic hydrazo compounds to give the amines (Houben-Weyl, 11/1, 522). Thus hydrazobenzene in the presence of palladium black, even in the absence of hydrogen, disproportionates to give aniline and azobenzene. Hydrogenation in the presence of nickel produces aniline in virtually quantitative yield. Under the same conditions, phenylhydrazine readily decomposes to give aniline and ammonia (Houben-Weyl, loc.cit. 538).

Sources & evidence

ORD record
ord-c6b0097aa71142f58cba5d8b4ccfa66e
Source dataset
uspto-grants-1985_03
Patent number
US04504424

Linked notes

Loading…