In this work, kinetics and mechanism of Ru(III) catalyzed oxidation of cyclohexanone by acidified solution of potassium bromate has been studied. Present study employ mercuric acetate Hg (OAc)2 as a scavenger for Br¯？ion to prevent parallel oxidation by bromine. The kinetics and mechanism have also been studied in the temperature range of 30°C - 45°C. The reaction exhibits first order kinetics with respect to Ru (III), while zero order kinetics with respect to KBrO3 and HClO4. The influence of Hg(OAc)2 and ionic strength on the rate of reaction was found to be insignificant. Positive effect in the reaction mixture was also observed upon addition of chloride ion; while as the negative effect was revealed with acetic acid. A suitable mechanism in conformity with the kinetic observations has been proposed and the rate law is derived on the basis of obtained data. The various activation parameters such as energy of activation (ΔE*), Arrhenius factor (A), entropy of activation (ΔS*) were calculated from the rate measurements at 30°C, 35°C - 40°C and 45°C.
References
[1]
Srivastava, S. and Sharma, R.K. (2006) Mechanistic Study of Ruthenium(III) Catalysed Oxidation of Leucine by Alkaline N-Bromoacetamide. Oxidation Communication, 2, 343-349.
[2]
Srivastava, S. and Singh, S. (2004) Kinetic Study of Ruthenium(III) Catalyzed Oxidation of Proline by Bromate in Acidic Medium. Journal of Indian Chemical Society, 18, 295.
[3]
Srivastava, S., Kumar, A. and Srivastava, P. (2006) A Kinetic Study of RuIII Catalyzed Oxidation of Maltose by Potassium Bromate in Alkaline Medium. Journal of Indian Chemical Society, 83, 347-350.
[4]
Srivastava, S., Sharma, R.K. and Singh, S (2006) Kinetics and Mechanism of Iridium(III) Catalyzed Oxidation of Some Cyclic Alcohols by Potassium Bromate in Acidic Medium. Journal of Indian Chemical Society, 83, 282-287.
[5]
Singh, A., Singh, S., Singh, A. and Singh, B. (2005) Mechanistic Study of Osmium(VIII) Promoted Oxidation of Crotonic Acid by Aqueous Alkaline Solution of Potassium Bromate. Transition Metal Chemistry, 30, 610-615.
https://doi.org/10.1007/s11243-005-3850-8
[6]
Ahmed, I. and Ashraf, C.M (1979) Kinetics and Mechanism of Palladium (II) Chloride Catalyzed Oxidation of Allyl Alcohol by Potassium Hexacyanoferrate(III). International Journal of Chemical Kinetics, 11, 813-819.
https://doi.org/10.1002/kin.550110802
[7]
Sergar, V., Veeresh, T.M. and Nandibewoor, S.T (2007) Osmium(VIII) Catalysed Oxidation of l-leucine by a New Oxidant, Diperiodatoargentate(III) in Aqueous Alkaline Medium. Journal of Molecular Catalysis: A Chemical, 271, 253-260.
https://doi.org/10.1016/j.molcata.2007.03.007
[8]
Srivastava, S., Singh, S. and Srivastava, P. (2008) Ruthenium(VIII) Catalyzed Oxidation of Some Cyclic Alcohols by Sodium Periodate in Alkaline Medium. Asian Journal of Chemistry, 20, 317-323.
[9]
Singh, P., Raghuvanshi, R. and Raghuvanshi, R. (2009) Comparative Study on Pd(II) and Ru(III) Catalyzed Oxidation of α-amino-β-hydroxypropionic Acid (dl-serine) by Acid Bromate: A Kinetic Study. Oriental Journal of Chemistry, 25, 1047-1052.
[10]
Srivastava, S., Khare, P., Singh, S. and Srivastava, S. (2008) Ru(III) and Ir(III) Catalysed Oxidation of Citric Acid by N-bromosuccinimide. A Comparative Kinetic Study. Oxidation Communications, 31, 327-334.
[11]
Srivastava, S., Awasthi, A. and Singh, K. (2004) Ruthenium (III) Catalyzed Oxidation of Cyclopentanol and Cyclohexanol by N-Bromoacetamide. International Journal of Chemical Kinetics, 37, 275-281. https://doi.org/10.1002/kin.20076
[12]
Fiegl, F. (1996) Spot Test in Organic Analysis. Elsevier, New York, 325.
[13]
Srivastava, S. and Singh, B. (1991) Kinetics and Mechanism of Ruthenium Tetroxide Catalysed Oxidation of Cyclic Alcohols by Bromate in a Base. Transition Metal Chemistry, 16, 466. https://doi.org/10.1007/BF01129466
[14]
Subramanian, V.N. and Thigarajan, V. (1969) Mechanism of Oxidation of Alcohols with N-Bromo succinimide. Canadian Journal of Chemistry, 47, 694.
https://doi.org/10.1139/v69-108
[15]
Bailer, J.C. (1964) Partial Resolution of Diamines, Amino Acids, and Dicarboxylic Acids through Coordination with Optically Active Ligands. Chemistry of Coordination Compounds, Reinhold, New York, 4.
[16]
Reddy, C.S. and Sundaram, E.V (1989) Mechanism of Acid Bromate Oxidation of Trans Mono-Substituted Cinnamic Acids: Structure Reactivity Correlation—A Non-Linear Hammett’s Plot. Tetrahedron, 45, 2109-2126.
https://doi.org/10.1016/S0040-4020(01)80072-7
