Chromic Acid Oxidation of Methylaminopyrazole Formamidine in Sulfuric Acid Medium: A Kinetic and Mechanistic Approach
American Journal of Physical Chemistry
Volume 5, Issue 1, February 2016, Pages: 1-9
Received: Jan. 1, 2016; Accepted: Jan. 8, 2016; Published: Jan. 25, 2016
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Ahmed Fawzy, Chemistry Department, Faculty of Applied Science, Umm Al-Qura University, Makkah, Saudi Arabia; Chemistry Department, Faculty of Science, Assiut University, Assiut, Egypt
Ismail Althagafi, Chemistry Department, Faculty of Applied Science, Umm Al-Qura University, Makkah, Saudi Arabia
Fahd Tirkistani, Chemistry Department, Faculty of Applied Science, Umm Al-Qura University, Makkah, Saudi Arabia
Mohamed Shaaban, Chemistry Department, Faculty of Applied Science, Umm Al-Qura University, Makkah, Saudi Arabia; Chemistry Department, Faculty of Science, Cairo University, Cairo, Egypt
Moataz Morad, Chemistry Department, Faculty of Applied Science, Umm Al-Qura University, Makkah, Saudi Arabia
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The kinetics of chromic acid oxidation of one of aminopyrazole formamidine derivatives, namely N,N-dimethyl-N’ -(5-methyl-1H-pyrazol-3-yl) formamidine (MAPF)in sulfuric acid solutions has been investigated at constant ionic strength and temperature. The progress of the reaction was followed spectrophotometrically. The reaction showed a first order dependence on [chromic acid] and fractional-first order dependences with respect to [MAPF] and [H+]. Increasing ionic strength and solvent polarity of the reaction medium had no significant effect on the oxidation rate. Addition of AgI, PdII and RuIII catalysts was found to enhance the reaction rate and the order of catalytic efficiency is: AgI > RuIII > PdII. The final oxidation products of MAPF are identified by spectral and elemental analysis as methylaminopyrazole, dimethylamine and carbon dioxide. A spectral evidence for the formation of chromium(III) product was obtained. A reaction mechanism adequately describing the observed kinetic behavior is proposed, and the reaction constants involved in the different steps of the mechanism have been evaluated. The activation parameters with respect to the rate-determining step of the reaction, along with thermodynamic quantities of the equilibrium constants, are presented and discussed.
Kinetics, Mechanism, Oxidation, Chromic Acid, Methylaminopyrazole Formamidine
To cite this article
Ahmed Fawzy, Ismail Althagafi, Fahd Tirkistani, Mohamed Shaaban, Moataz Morad, Chromic Acid Oxidation of Methylaminopyrazole Formamidine in Sulfuric Acid Medium: A Kinetic and Mechanistic Approach, American Journal of Physical Chemistry. Vol. 5, No. 1, 2016, pp. 1-9. doi: 10.11648/j.ajpc.20160501.11
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Beeman RW, Matsumura F (1973) Chlordimeform: a pesticide acting upon amine regulatory mechanisms. Nature. 242: 273-274.
Aziz AA, Knowles CO (1973) Inhibition of monoamine oxidase by the pesticides chlordimeform and related compounds. Nature 242: 417-418.
Leung VSK, Chan TYK, Yeung VTF (1999) Ami-traz poisoning in humans, Clinical Toxicol. 37: 513-514.
Nakayama A, Sukekawa M, Eguchi Y (1997) Stereo-chemistry and active conformation of a novel insecticide Acetamiprid. Pesticide Sci. 51: 157-164.
Katz SA, Salem H (1993) The toxicology of chromium with respect to its chemical speciation: a review. J. Appl. Toxicol. 13: 217–224.
Barnhart J (1997) Chromium in soil: perspectives in chemistry, health, and environmental regulation. J. Soil Contamination 6l 561–568.
Costa M (1997) Toxicity and carcinogenicity of CrVI in animal models and humans. CRC, Crit. Rev. Toxicol. 27: 431-442.
Chimatadar SA, Koujalagi SB, Nandibewoor ST (2001) Kinetics and mechanism of palladium(II) catalyzed chromium(VI) oxidation of mercury(I) in aqueous sulphuric acid. Transition Met. Chem. 26: 662-667; Chimatadar SA, Basavaraj T, Nandibewoor ST (2006) Mechanistic study of quinoliniumdichromate (QDC) oxidation of mercury(I) in aqueous sulfuric acid in the presence of micro amounts of palladium(II). Autocatalysis in catalysis. Polyhedron 25: 2976-2984.
Sen Gupta KK, Chakladar JK (1974) Kinetics of the chromic acid oxidation of arsenic(II). J. Chem. Soc. Dalton Trans. 2: 222–225.
Sen Gupta KK, Chakladar JK, Chatterjee AK, Chakladar JK (1973) Kinetics of the oxidation of hypophosphorous and phosphorous acids by chromium(VI). J. Inorg. Nucl. Chem. 35: 901–908.
Espenson JH (1970) Oxidation of transition metal complexes by chromium(VI). Accounts Chem. Res. 3: 347–351.
Hasan F, Rocek J (1975) Three-electron oxidations. IX. Chromic acid oxidation of glycolic acid. J. Am. Chem. Soc. 97: 1444–1450.
Khan Z, Id-Din K (2001) Effect of manganese(II) ions on the oxidation of maleic and oxaloethanoic acids by aqueous H2CrO4. Transition Met. Chem. 26: 672–678.
Manhas MS, Kumar P, Mohamed F, Khan Z (2008) Oxidative degradation of non-ionic surfactant (Triton X-100) by chromium(VI). Coll. Surf. A 320: 240–246.
Odebunmi EO, Obike AI, Owalude SO (2009) Kinetics and mechanism of oxidation of D-xylose and L-arabinose by chromium(VI) ions in perchloric acid medium, Int. J. Biolog. Chem. Sci. 3: 178-185.
Fawzy A, Shaaban MR (2014) Kinetic and mechanistic investigations on the oxidation of N’-heteroaryl unsymmetrical formamidines by permanganate in aqueous alkaline medium, Transition Met. Chem. 39: 379-386.
Vogel AI (1973) Text Book of Practical Organic Chemistry including Quantitative Organic Analysis. 3rd edn, pp. 332, ELBS, Longman.
Feigl F (1957) Spot Tests in Organic Analysis, Elsevier, New York, NY, USA.
Bayen R, Das AK (2009) Kinetics and mechanism of oxidation of D-galactose by chromium(VI) in presence of 2,2´-bipyridine catalyst in aqueous micellar media. The Open Catal. J. 2: 71-78.
Espenson JH, King EL (1963) Kinetics and mechanism of reaction of chromium(VI) and iron(II) species in acidic medium, J. Am. Chem. Soc. 85: 3328–3333.
Espenson EH, Wang RT (1972) The oxidation of uranium(IV) by chromium(VI) and the induced oxidation of iodide ions. Inorg. Chem. 11: 955–959.
Sen Gupta KK, Sarkar T (1975) Kinetics of the chromic acid oxidation of glyoxylic and pyruvic acids. Tetrahedron 31: 123–129.
Bose RN, Moghaddas B, Gelerinter E (1992) Long-lived chromium(IV) and chromium(V) metabolites in the chromium(VI)-glutathione reaction: NMR, ESR, HPLC, and kinetic characterization, Inorg. Chem. 31: 1987-1994.
Milazzo, G, Caroli S, Sharma VK (1978) Tables of Standard Electrode Metal Potentials, Wiley & Sons, New York.
Bailey N, Carrington A, Lott KAK, Symons MCR (1960) Structure and reactivity of the oxyanions of transition metals. Part VIII. Acidities and spectra of protonated oxyanions, J. Chem. Soc. 290–297.
Sasaki Y (1962) Equilibrium studies on polyanions. 9. The first steps of acidification of chromate Ion in 3 M Na(ClO4) Medium at 25 degrees C. Acta Chem. Scand. 16: 719–734.
Naik PK, Chimatadar SA, Nandibewoor ST (2008) A kinetic and mechanistic study of the oxidation of tyrosine by chromium(VI) in aqueous perchloric acid medium Transition Met. Chem. 33: 405–410.
Day MC, Selbin JJ (1964) Theoretical inorganic chemistry, Reinhold Publishing Corporation, New York.
Fawzy A, Ashour SS, Musleh MA, Hassan RM, Asghar BH (2014) Kinetics and mechanistic approach to the chromic acid oxidation of L-tryptophan with a spectral detection of chromium(III) product. J. Saudi Chem. Soc. in press.
Frost AA, Person RG (1971) Kinetics and Mechanism, Wiley Eastern, New Delhi, 1970; C. H. Rochester, Progress in Reaction Kinetics, Pergamon Press, Oxford; Laidler K (1965) Chemical Kinetics, McGraw-Hill, New York.
Amis ES (1966) Solvent Effects on Reaction Rates and Mechanism, Academic Press, New York.
Freeman WH (2010)Dissociation Constants. Inorganic Chemistry, pp. 22-25, 1983; W. H. Freeman, and Company, New York; IUPAC SC-Database (2001) A comprehensive database of published data on equilibrium constants of metal complexes and ligands. Inorganic Chemistry, Higher Education Press, Beijing, China.
Rangappa KS, Raghavendra MP, Mahadevappa DS, Channagouda D (1988) Sodium N-chlorobenzenesulfonamide as a selective oxidant for hexosamines in alkaline medium:  A kinetic and mechanistic study. J. Org. Chem. 63: 531-536.
Fawzy A (2014) Influence of copper(II) catalyst on the oxidation of L-histidine by platinum(IV) in alkaline medium: a kinetic and mechanistic study. Transition Met. Chem. 39: 567-576.
Fawzy A, Asghar BH (2015) Kinetics and mechanism of uncatalyzed and silver(I)-catalyzed oxidation of L-histidine by hexachloroplatinate(IV) in acid medium. Transition Met. Chem. 40: 287-295.
Shukla A, Gupta S, Upadhyay SK (1991) Pd(II) complexes of amino alcohols and their reaction with chloramine-T: A kinetic study, Int. J. Chem. Kinet. 23: 279-288.
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