4-Aminodiphenylamine

4-Aminodiphenylamine
Names
	Preferred IUPAC name N1-Phenylbenzene-1,4-diamine
	Other names 4-Aminodiphenylamine; p-Aminodiphenylamine; N-Phenyl-p-phenylenediamine; N-Phenyl-1,4-phenylenediamine; PPD;
Identifiers
CAS Number	101-54-2;
3D model (JSmol)	Interactive image;
Beilstein Reference	908935
ChEBI	CHEBI:59038;
ChEMBL	ChEMBL572203;
ChemSpider	7283;
ECHA InfoCard	100.002.684
EC Number	202-951-9;
Gmelin Reference	241334
PubChem CID	7564;
RTECS number	ST3150000;
UNII	007X4XXS71;
UN number	1673
CompTox Dashboard (EPA)	DTXSID7025895 ;
	InChI InChI=1S/C12H12N2/c13-10-6-8-12(9-7-10)14-11-4-2-1-3-5-11/h1-9,14H,13H2 Key: ATGUVEKSASEFFO-UHFFFAOYSA-N;
	SMILES C1=CC=C(C=C1)NC2=CC=C(C=C2)N;
Properties
Chemical formula	C12H12N2
Molar mass	184.242 g·mol−1
Appearance	purple–black or dark purple
Density	1.09 g/mL
Melting point	75 °C (167 °F; 348 K)
Boiling point	354 °C (669 °F; 627 K)
Hazards
	GHS labelling:
Pictograms
Signal word	Warning
Hazard statements	H302, H317, H319, H410
Precautionary statements	P261, P264, P270, P272, P273, P280, P301+P312, P302+P352, P305+P351+P338, P321, P330, P333+P313, P337+P313, P363, P391, P501
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

4-Aminodiphenylamine is a diphenylamine with an additional amine substituent. This dimer of aniline has various industrial uses, including as a hair dye ingredient, but also has raised concerns about toxicity by skin contact.^[1] It is also a starting material for the synthesis of 6PPD, an antiozonant for various rubber products.^[2] A colorimetric test for the quantitative analysis of nitrite, at levels below 100 nanograms per milliliter, is based on nitrite-catalyzed coupling of 4-aminodiphenylamine with N,N-dimethylaniline.^[3]

Synthesis

The most common route of industrial production is by the metal catalysed reaction of aniline with 4‑nitrochlorobenzene to give 4‑nitrodiphenylamine (Buchwald–Hartwig amination):

Subsequent hydrogenation gives 4-aminodiphenylamine.^[4] An alternative is the direct reaction of nitrobenzene with aniline via a nucleophilic aromatic substitution of hydrogen (vicarious nucleophilic substitution).^[5]^[6] This again requires a reduction step but is a good example of industrial green chemistry as it eliminates the need for organochlorine starting materials and metal catalysts.

References

^ Khanna, S. K.; Tewari, Pushpa; Joshi, Anil; Singh, G. B. (1987). "Studies on the skin uptake and efflux kinetics of N-phenyl-p-phenylenediamine: an aromatic amine intermediate". International Journal of Cosmetic Science. 9 (3): 137–147. doi:10.1111/j.1467-2494.1987.tb00470.x. PMID 19456976. S2CID 205555627.
^ Engels, Hans-Wilhelm; Weidenhaupt, Herrmann‐Josef; Pieroth, Manfred; Hofmann, Werner; Menting, Karl‐Hans; Mergenhagen, Thomas; Schmoll, Ralf; Uhrlandt, Stefan (2007). "Rubber, 4. Chemicals and Additives". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a23_365.pub2. ISBN 978-3527306732.
^ Kadowaki, Ryoichi; Nakano, Shigenori; Kawashima, Takuji (1999). "Sensitive flow injection colorimetry of nitrite by catalytic coupling of N-phenyl-p-phenylenediamine with N,N-dimethylaniline". Talanta. 48 (1): 103–107. doi:10.1016/s0039-9140(98)00227-6. PMID 18967448.
^ Bochkarev, V.V.; Soroka, L.S.; Bashkin, J.K. (December 2016). "Resource-efficient technology to produce 4-aminodiphenylamine". Resource-Efficient Technologies. 2 (4): 215–224. doi:10.1016/j.reffit.2016.10.011.
^ Stern, Michael K.; Hileman, Fredrick D.; Bashkin, James K. (November 1992). "The direct coupling of aniline and nitrobenzene: a new example of nucleophilic aromatic substitution for hydrogen". Journal of the American Chemical Society. 114 (23): 9237–9238. doi:10.1021/ja00049a095.
^ Bashkin, James; Rains, Roger; Stern, Michael (1999). "Taking green chemistry from the laboratory to chemical plant". Green Chemistry. 1 (2): G41. doi:10.1039/GC990G41.

[1] Khanna, S. K.; Tewari, Pushpa; Joshi, Anil; Singh, G. B. (1987). "Studies on the skin uptake and efflux kinetics of N-phenyl-p-phenylenediamine: an aromatic amine intermediate". International Journal of Cosmetic Science. 9 (3): 137–147. doi:10.1111/j.1467-2494.1987.tb00470.x. PMID 19456976. S2CID 205555627.

[2] Engels, Hans-Wilhelm; Weidenhaupt, Herrmann‐Josef; Pieroth, Manfred; Hofmann, Werner; Menting, Karl‐Hans; Mergenhagen, Thomas; Schmoll, Ralf; Uhrlandt, Stefan (2007). "Rubber, 4. Chemicals and Additives". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a23_365.pub2. ISBN 978-3527306732.

[3] Kadowaki, Ryoichi; Nakano, Shigenori; Kawashima, Takuji (1999). "Sensitive flow injection colorimetry of nitrite by catalytic coupling of N-phenyl-p-phenylenediamine with N,N-dimethylaniline". Talanta. 48 (1): 103–107. doi:10.1016/s0039-9140(98)00227-6. PMID 18967448.

[efficient-4] Bochkarev, V.V.; Soroka, L.S.; Bashkin, J.K. (December 2016). "Resource-efficient technology to produce 4-aminodiphenylamine". Resource-Efficient Technologies. 2 (4): 215–224. doi:10.1016/j.reffit.2016.10.011.

[5] Stern, Michael K.; Hileman, Fredrick D.; Bashkin, James K. (November 1992). "The direct coupling of aniline and nitrobenzene: a new example of nucleophilic aromatic substitution for hydrogen". Journal of the American Chemical Society. 114 (23): 9237–9238. doi:10.1021/ja00049a095.

[6] Bashkin, James; Rains, Roger; Stern, Michael (1999). "Taking green chemistry from the laboratory to chemical plant". Green Chemistry. 1 (2): G41. doi:10.1039/GC990G41.

[1]

[2]

[3]

[4]

[5]

[6]