Chemical Papers

, Volume 73, Issue 2, pp 375–385 | Cite as

Conversion of anilines into azobenzenes in acetic acid with perborate and Mo(VI): correlation of reactivities

  • C. KarunakaranEmail author
  • R. Venkataramanan
Original Paper


Azobenzenes are extensively used to dye textiles and leather and by tuning the substituent in the ring, vivid colours are obtained. Here, we report preparation of a large number of azobenzenes in good yield from commercially available anilines using sodium perborate (SPB) and catalytic amount of Na2MoO4 under mild conditions. Glacial acetic acid is the solvent of choice and the aniline to azobenzene conversion is zero, first and first orders with respect to SPB, Na2MoO4 and aniline, respectively. Based on the kinetic orders, UV–visible spectra and cyclic voltammograms, the conversion mechanism has been suggested. The reaction rates of about 50 anilines at 20–50 °C and their energy and entropy of activation conform to the isokinetic or Exner relationship and compensation effect, respectively. However, the reaction rates, deduced by the so far adopted method, fail to comply with the Hammett correlation. The specific reaction rates of molecular anilines, obtained through a modified calculation, conform to the Hammett relationship. Thus, this work presents a convenient inexpensive non-hazardous method of preparation of a larger number of azobenzenes, and shows the requirement of modification in obtaining the true reaction rates of anilines in acetic acid and the validity of Hammett relationship in the conversion process, indicating operation of a common mechanism.


Homogeneous catalysis Kinetics Oxidations Structure–reactivity relationships Azo dyes 

Supplementary material

11696_2018_599_MOESM1_ESM.pdf (10.4 mb)
Supplementary material 1 (PDF 10695 kb)


  1. Almohareb T (2017) Management of discolored endodontically treated tooth using sodium perborate. J Int Oral Health 9:133–135. Google Scholar
  2. Aslam MH, Burdon AG, Chapman NB, Shorter J, Charton M (1981) The separation of polar and steric effects. Part 14. Kinetics of the reactions of benzoic acid and of ortho-substituted benzoic acids with diazodiphenylmethane in various alcohols. J Chem Soc Perkin Trans 2:500–508. CrossRefGoogle Scholar
  3. Buckingham J (1995) Dictionary of organic compounds. Chapman & Hall/CRC, LondonGoogle Scholar
  4. Buckingham J, Donaghy SM, Cadogan JIG, Raphael RA, Roes CW (1996) Dictionary of organic compounds. Chapman & Hall, LondonGoogle Scholar
  5. Cai S, Rong H, Yu X, Liu X, Wang D, He W, Li Y (2013) Room temperature activation of oxygen by monodispersed metal nanoparticles: oxidative dehydrogenative coupling of anilines for azobenzene syntheses. ACS Catal 3:478–486. CrossRefGoogle Scholar
  6. Cvijetic IN, Vitorovic-Todorovic MD, Juranic IO, Drakulic BJ (2013) Reactivity of (E)-4-aryl-4-oxo-2-butenoic acid arylamides toward 2-mercaptoethanol. A LFER study. Monatsh Chem 144:1815–1824. CrossRefGoogle Scholar
  7. Dean JA (1987) Handbook of organic chemistry. McGraw-Hill, New YorkGoogle Scholar
  8. Dutta B, Biswas S, Sharma V, Savage NO, Alpay SP, Suib SL (2016) Mesoporous manganese oxide catalyzed aerobic oxidative coupling of anilines to aromatic azo compounds. Angew Chem Int Ed 55:2171–2175. CrossRefGoogle Scholar
  9. Gao BB, Zhang M, Chen XR, Zhu DL, Yu H, Zhang WH, Lang JP (2018) Carbon-based AuAg alloy nanoparticles via the heterometallic [Au4Ag4] cluster approach for efficient oxidative coupling of anilines. Dalton Trans 47:5780–5788. CrossRefGoogle Scholar
  10. Grirrane A, Corma A, Garcia H (2008) Gold-catalyzed synthesis of aromatic azo compounds from anilines and nitroaromatics. Science 322:1661–1664. CrossRefGoogle Scholar
  11. Hansch C, Leo A, Taft RW (1991) A survey of Hammett substituent constants and resonance and field parameters. Chem Rev 91:165–195. CrossRefGoogle Scholar
  12. Indi YM, Wasif A, Patel AA (2017) Activated bleaching with sodium perborate and potassium persulphate. Indian J Fibre Text Res 42:235–240.
  13. Jasinski R, Kwiatkowska M, Baranski A (2012) Kinetics of the [4 + 2] cycloaddition of cyclopentadiene with (E)-2-aryl-1-cyano-1-nitroethenes. Monatsh Chem 143:895–899. CrossRefGoogle Scholar
  14. Kamlet MJ, Abboud JLM, Abraham MH, Taft RW (1983) Linear salvation energy relationship. 23. A comprehensive collection of the solvatochromic parameters, π*, α, and β and some methods for simplifying the generalized solvatochromic equation. J Org Chem 48:2877–2887. CrossRefGoogle Scholar
  15. Karunakaran C, Kamalam R (2000) On the mechanism of the perborate oxidation of organic sulphides in glacial acetic acid. Eur J Org Chem.<3261:AID-EJOC3261>3.0.CO:2.0 Google Scholar
  16. Karunakaran C, Kamalam R (2002a) Mechanism and reactivity in perborate oxidation of anilines in acetic acid. J Chem Soc Perkin Trans 2:2011–2018. CrossRefGoogle Scholar
  17. Karunakaran C, Kamalam R (2002b) Structure-reactivity correlation of anilines in acetic acid. J Org Chem 67:1118–1124. CrossRefGoogle Scholar
  18. Karunakaran C, Muthukumaran B (1995) Molybdenum(VI) catalysis of perborate or hydrogen peroxide oxidation of iodide ion. Transit Met Chem 20:460–462. CrossRefGoogle Scholar
  19. Karunakaran C, Venkataramanan R (2006a) Mo(VI)-catalysis of perborate oxidation in acetic acid: oxidation of dimethyl and dibenzyl sulfoxides. Catal Commun 7:236–239. CrossRefGoogle Scholar
  20. Karunakaran C, Venkataramanan R (2006b) Mo(VI)-catalysis of perborate oxidation of aryl sulphides in acetic acid. J Chem Res. Google Scholar
  21. Liu L, Guo QX (2001) Isokinetic relationship, isoequilibrium relationship, and enthalpy-entropy compensation. Chem Rev 101:673–696. CrossRefGoogle Scholar
  22. Lydon JD, Schwane LM, Thompson RC (1987) Equilibrium and kinetic studies of the peroxo complex of molybdenum(VI) in acidic perchlorate solution. Inorg Chem 26:2606–2612. CrossRefGoogle Scholar
  23. Ma H, Li W, Wang J, Xiao G, Gong Y, Qi C, Feng Y, Li X, Bao Z, Cao W, Sun Q, Veaceslav C, Wang F, Lei Z (2012) Organocatalytic oxidative dehydrogenation of aromatic amines for the preparation of azobenzenes under mild conditions. Tetrahedron 68:8358–8366. CrossRefGoogle Scholar
  24. McKillop A, Sanderson WR (1995) Sodium perborate and sodium percarbonate: cheap, safe and versatile oxidizing agents for organic synthesis. Tetrahedron 51:6145–6166. CrossRefGoogle Scholar
  25. Merino E (2011) Synthesis of azobenzenes: the coloured pieces of molecular materials. Chem Soc Rev 40:3835–3853. CrossRefGoogle Scholar
  26. Muzart J (1995) Sodium perborate and sodium percarbonate in organic synthesis. Synthesis, pp 1325–1347.
  27. Paris E, Bigi F, Cauzzi D, Maggi R, Maestri G (2018) Oxidative dimerization of anilines with heterogeneous sulfonic acid catalysts. Green Chem 20:382–386. CrossRefGoogle Scholar
  28. Perrin DD (1965) Dissociation constants of organic bases in aqueous solution. Butterworths, LondonGoogle Scholar
  29. Salter-Blanc AJ, Bylaska EJ, Lyon MA, Ness SC, Tratnyek PG (2016) Structure-activity relationships for rates of aromatic amine oxidation by manganese dioxide. Environ Sci Technol 50:5094–5102. CrossRefGoogle Scholar
  30. Saraswat S, Sharma V, Banerji KK (2003) Kinetics and mechanism of oxidation of aliphatic primary alcohols by quinolinium bromochromate. Proc Indian Acad Sci (Chem Sci) 115:75–82.
  31. Seth K, Roy SR, Kumar A, Chakraborti AK (2016) The palladium and copper contrast: a twist to products of different chemotypes and altered mechanistic pathways. Catal Sci Technol 6:2892–2896. CrossRefGoogle Scholar
  32. Shorter J (1991) In: Zalewski RI, Krygowski TM, Shorter J (eds) Similarity models in organic chemistry, biochemistry and related fields. Elsevier, AmsterdamGoogle Scholar
  33. Sun S, Liu Y, Ma J, Pang S, Huang Z, Gu J, Gao Y, Xue M, Yuan Y, Jiang J (2018) Transformation of substituted anilines by ferrate(VI): kinetics, pathways, and effect of dissolved organic matter. Chem Eng J 332:245–252. CrossRefGoogle Scholar
  34. Swain CG, Swain MS, Powell AL, Alunni S (1983) Solvent effects on chemical reactivity. Evaluation of anion- and cation-solvation components. J Am Chem Soc 105:502–513. CrossRefGoogle Scholar
  35. Takada Y, Okumura S, Minakata S (2012) Oxidative dimerization of aromatic amines using t-BuOI: entry to unsymmetric aromatic azo compounds. Angew Chem Int Ed 51:7804–7808. CrossRefGoogle Scholar
  36. Tran L, Orth R, Parashos P, Tao Y, Tee CWJ, Thomas VT, Towers G, Truong DT, Vinen C, Reynolds EC (2017) Depletion rate of hydrogen peroxide from sodium perborate bleaching agent. J Endod 43:472–476. CrossRefGoogle Scholar
  37. Vyas S, Sharma PK (2002) Kinetics and mechanism of the oxidation of organic sulphides by 2,2′-bipyridinum chlorochromate. Proc Indian Acad Sci (Chem Sci) 114:137–148. CrossRefGoogle Scholar
  38. Yamada S, Bessho J, Nakasato H, Tsutsumi O (2018) Color tuning donor-acceptor-type azobenzene dyes by controlling the molecular geometry of the donor moiety. Dyes Pigment 150:89–96. CrossRefGoogle Scholar
  39. Zhang C, Jiao N (2010) Copper-catalyzed aerobic oxidative dehydrogenative coupling of anilines leading to aromatic azo compounds using dioxygen as an oxidant. Angew Chem Int Ed 49:6174–6177. CrossRefGoogle Scholar
  40. Zhu Y, Shi Y (2013) Facile Cu(I)-catalyzed oxidative coupling of anilines to azo compounds and hydrazines with diaziridinone under mild conditions. Org Lett 15:1942–1945. CrossRefGoogle Scholar

Copyright information

© Institute of Chemistry, Slovak Academy of Sciences 2018

Authors and Affiliations

  1. 1.Department of ChemistryAnnamalai UniversityAnnamalainagarIndia

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