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]

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
3D model (JSmol)
908935
ChEBI
ChEMBL
ChemSpider
ECHA InfoCard 100.002.684 Edit this at Wikidata
EC Number
  • 202-951-9
241334
RTECS number
  • ST3150000
UNII
UN number 1673
  • 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
  • C1=CC=C(C=C1)NC2=CC=C(C=C2)N
Properties
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:
GHS07: Exclamation markGHS09: Environmental hazard
Warning
H302, H317, H319, H410
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).

Synthesis

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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

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  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 205555627.137-147&rft.date=1987&rft_id=https://api.semanticscholar.org/CorpusID:205555627#id-name=S2CID&rft_id=info:pmid/19456976&rft_id=info:doi/10.1111/j.1467-2494.1987.tb00470.x&rft.aulast=Khanna&rft.aufirst=S. K.&rft.au=Tewari, Pushpa&rft.au=Joshi, Anil&rft.au=Singh, G. B.&rfr_id=info:sid/en.wikipedia.org:4-Aminodiphenylamine" class="Z3988">
  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 18967448.103-107&rft.date=1999&rft_id=info:doi/10.1016/s0039-9140(98)00227-6&rft_id=info:pmid/18967448&rft.aulast=Kadowaki&rft.aufirst=Ryoichi&rft.au=Nakano, Shigenori&rft.au=Kawashima, Takuji&rfr_id=info:sid/en.wikipedia.org:4-Aminodiphenylamine" class="Z3988">
  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.2016.10.011.215-224&rft.date=2016-12&rft_id=info:doi/10.1016/j.reffit.2016.10.011&rft.aulast=Bochkarev&rft.aufirst=V.V.&rft.au=Soroka, L.S.&rft.au=Bashkin, J.K.&rft_id=https://doi.org/10.1016%2Fj.reffit.2016.10.011&rfr_id=info:sid/en.wikipedia.org:4-Aminodiphenylamine" class="Z3988">
  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/ja00049a095.9237-9238&rft.date=1992-11&rft_id=info:doi/10.1021/ja00049a095&rft.aulast=Stern&rft.aufirst=Michael K.&rft.au=Hileman, Fredrick D.&rft.au=Bashkin, James K.&rfr_id=info:sid/en.wikipedia.org:4-Aminodiphenylamine" class="Z3988">
  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.