(A Peer Review Journal)
e–ISSN: 2408–5162; p–ISSN: 2048–5170


Pages: 856-860
I. B. Anweting, S.O. Idris and A.D.Onu

keywords: Intermediate, ionic strength, kinetic, oxidant, oxidation, reductant, stoichiometry


The reaction between thiourea (TU) and tetrakis(2,2’-bipyridine)-μ-oxodiiron (III) complex ([Fe2(bpy)4O]4+) hereafter referred to as Fe2O4+ has been studied in aqueous acidic media at hydrogen ion concentration ([H+]) of 0.001 moldm-3, constant ionic strength of 0.3 moldm-3(NaCl), T= 27 ±1°C and atwave length of maximum absorption (λmax) of 520 nm. The stoichiometry of reaction shows that one mole of oxidant is consumed per mole of reductant. The reaction is first order with respect to oxidant and reductant respectively and is not hydrogen ion and ionic strength dependent. The reaction conforms to the rate law: −d dt [Fe2O4+] = k2[Fe2O4+][TU]. Added SO 2 4 and CH3COO– inhibited the rate of reaction. The absence of both kinetics and spectroscopic evidence of intermediate complex formation suggest that the reaction proceeds by the outer-sphere mechanistic pathway and a mechanism is proposed.


Alamgir M &Epstein IR 1985. Complex dynamical behavior in a new chemical oscillator: the chlorite – thiourea reaction in a CSTR. Int. J. Chem.Kinetics, 17(4): 429 – 439. Al-Majthouls MM & Salman M 2012. Infrared spectroscopy interpretations on the reaction products resulted from the interaction between Co(II), Cu(II), Fe(III), Mn(II), Ni(II) and Zn(II) phosphate salts with urea at 85oC. J.Chem&Pharmac.Res., 4(3): 1856 - 1863. Ardiwilaga S 1999. Effects of cysteine and oxygen on recovery of cemented gold from leach liquors in a thiourea system. Minerals Engineering, 12(6): 645 - 653. Arifoglu MA, MarmerWN&Dudley RB 1992. Reaction of thiourea with hydrogenperoxide: 13CNMR studies of an oxidative -reductive bleaching process. Textile Res. J., 62: 94 – 100. Ayoko GA, IyunJF&Mamman S 1994. Oxidation of ethylenediaminetetraacetate by tris(diimine) iron(III) complexes and the dodecatungstocobaltate(III). A comparative kinetic and mechanistic study.Transition Metal Chem., 19:151-153 Ayoko GA, IyunJF&Faruk YA 1999. Oxidation of nitrous acid by tris(diimine) iron(III) complexes. Indian J. Chem.,38A: 458-461. Ayres JA 1970. Decontamination of Nuclear Reactors and Equipment. Ronald Press Company, New York, pp. 177. Begum SA, Hossain M &Podder J2009. An investigation of the growth and characterization of thiourea single crystal growth from aqueous solutions.J. Bangladesh Acad. Sci., 33 (1): 63 - 70. Cagarra J, Gacen J, Caro M &Pepio M1988.Bleaching with thiourea dioxide.J. Soc. Dyers Colour, 104: 273 - 279. Chimere I, Mohammed A &Emmanuel J 1985.Laboratory Exercise in Chemistry.Al united industries and shipping INC, Taipei, Taiwan, pp. 79 - 85. David PG 1973. Binuclear and mononuclear mixed ligands complexes of iron(III) with thiocyanaye and aromatic diimines. J. Inorganic & Nuclear Chem., 35:1463-1470. Groenewald T 1977. Potential applications of thiourea in the processing of gold.J. South Africa Institute of Mineral &Metallurgy, 217 - 223. Hilsona G &MonhemiusAJ 2006. Alternatives to cyanide in gold mining industry: what prospects for the future? J. Cleaner Production, 14(12-13): 1158-1167. Idris SO,IyunJF&AgbajiEB 2004. Kinetics and mechanism of the oxidation of catechol by Fe2(bipy)4O4+ in aqueous hydrochloric acid medium. Chemclass Journal, 29-30. IyunJF&Adegite A 1990. Kinetics and mechanism of the reduction of dichlorotetrakis(2, 2ˈ-bipyridine)-μ- oxodiruthenium ion by Ti(III)-EDTA in aqueous Acidic Medium. Bull. Chem. Soc. Ethiopia, 4:27-31. IyunJF 2004. Oxidation of some tris(diamine) iron(II) and tris(substituted diamine) iron(II) complexes by aqueous acidic bromine solution. An assessment of the Marcus model for non- complementary reactions.Chemclass Journal, 59-63. Klern H, Lux J, Noll D, Reider W &Phillips H 1971. Proceedings of the American Power Conference, 33. Illinois Institute of Technology, Chicago, IL, pp. 702 - 729. Kumar CC, Chandaraiah U, SiddiquiMAA&Kordlikars S 1991. Kinetics and mechanism of the oxidation of amino acids of the type NH2CH(R)COOH with hexachloroiridate(IV). Indian J. Chem., 30(A): 714 – 715. Mertschenk B &Beck F 1995.Thiourea and thiourea derivatives. In: Elvers, B., Hawkins, S and Russey, W., eds, Ullmann’s encyclopedia of industrial chemistry. Vol. A26, 5th rev. ed., New York, VCH Publishers, pp. 803 - 815. Mohammed Y, Idris SO &IyunJF 2014. Redox kinetics and mechanisms of oxidation thiourea by diaquotetrakis(2,2ˈ– bipyridine)-μ-oxodiruthenium(III) ion in aqueous perchloric acid. Int. Res. J. Pure &Appl. Chem., 4(6): 819- 833. Murugan S 2013.Microscale experiments in organic and inorganic chemistry. J.Applicable Chem., 2(1): 1- 13. Osunlaja AA, Idris SO, IyunJF&Uzairu A 2013. Kinetics and mechanism of thiourea oxidation by Oxygenated