Roberto Sanchirico

Manganese-catalysed ozonation of glyoxalic acid in aqueous solutions

Manganese-catalysed ozonation of glyoxalic acid in aqueous solutions has been investigated in the pH range 2.0-4.0. The addition of manganese ions (Mn(II) or Mn(IV)) to a glyoxalic acid-ozone system allows the substrate to be oxidized through a mechanism different from that reported for uncatalysed ozonation, as underlined by the formation of methanoic acid. The presence of solid MnO2 results in a further increase in the system reactivity. High levels of mineralization are generally achieved during glyoxalic acid-catalysed ozonation. # 2000 Society of Chemical Industry

Thermal decomposition of ethyl parathion

The thermal decomposition of ethyl parathion, an organophosphorus pesticide, has been studied by coupling calorimetric and chemical analysis. The decomposition process develops through two exothermic events with production of relevant amounts of uncondensible gases (final pressure 50 bar in an ARC run). A simple autocatalytic kinetic model has been adopted for simulating the first stage of the decomposition process.

Thermal decomposition of 2-nitrobenzoic acid

The thermal decomposition of 2-nitrobenzoic acid is investigated by means of adiabatic and quasi-isothermal calorimetry. The decomposition process develops according to zero order kinetics which gives substantial support to the intervention of vapour-phase reaction. The apparent activation energy of 144·8 kJ mol−1 is evaluated. Chemical analysis gives support to the proposal of reliable reaction mechanisms.

Hazard assessment of 4-nitrobenzoic acid production process

4-Nitrobenzoic acid is produced through the oxidation of 4-nitrotoluene by means of diluted nitric acid. Since accidents have been reported for this process, the behaviour of the chemical system at varying operating conditions has been investigated by means of calorimetric techniques. The results evidenced the possible occurrence of the loss of the control of the primary and/or secondary reactions.