Kinetics and mechanism of the copper-catalysed oxygenation of 2-nitropropane

Éva Balogh-Hergovich, Zoltán Gréczi, József Kaizer, Gábor Speier, Marius Réglier, Michel Giorgi, László Párkányi

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8 Citations (Scopus)

Abstract

Primary and secondary nitro compounds react with dioxygen in the presence of copper metal and N ligands such as N,N,N′,N′-tetramethylethylenediamine (tmeda), 2,2′-bipyridine (bpy), and 1,10-phenantroline (phen) in various solvents to form aldehydes or ketones. More coordinating solvents as well as donor N ligands accelerate the reaction remarkably. The oxygenolysis of 2-nitropropane (NPH) in the presence of copper and tmeda in DMF results in acetone and acetone oxime. The amount of tmeda influences the chemoselectivity, higher tmeda concentrations preferentially lead to the formation of the oxime. The kinetics of the reaction, measured at 90 °C, resulted in a rate equation of first-order dependence on copper and dioxygen and second-order dependence on 2-nitropropane. The rate constant, activation enthalpy, and entropy at 363.16 K are as follows: kcat = (5.37 ± 0.34) × 10-2 Mol-3 dm9 s-1, Ea = 131 ± 4 kJ mol-1, ΔH‡ = 127 ± 4 kJ mol-1 and ΔS‡ = 80 ± 13 J mol-1 K-1. The catalytically active intermediates CuII(NP)2(tmeda) and CuII(NO2)2(tmeda) in the catalytic cycle were isolated and their structures determined by X-ray crystallography. The kinetics of the stoichiometric oxygenation of CuII(NP)2(tmeda) to CuII(NO2)2(tmeda) and acetone resulted in the overall second-order rate equation with a rate constant, activation enthalpy, and entropy at 313.16 K of ks = 0.46 ± 0.02 mol-1 dm3 s-1, Ea = 38 ± 1 kJ mol-1, ΔH‡ = 35 ± 1 kJ mol-1 and ΔS‡ = -142 ± 13 J mol-1 K-1, respectively.

Original languageEnglish
Pages (from-to)1687-1696
Number of pages10
JournalEuropean Journal of Inorganic Chemistry
Issue number7
DOIs
Publication statusPublished - Jan 1 2002

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Keywords

  • 2-Nitropropane
  • Copper
  • Copper nitronates
  • Dioxygenase
  • Kinetics
  • Oxygenation

ASJC Scopus subject areas

  • Inorganic Chemistry

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