ROLE OF THE 4TH-PERIOD METAL-OXIDES ON THE PYROLYSIS OF SODIUM-CHLORITE

The non-isothermal pyrolysis of pure sodium chlorite as self or mixed with some fourth-period metal oxides (10% (w/w)) was studied using the rmogravimetric (TG) and derivative thermogravimetric (DTG) analysis. T he pyrolysis of sodium chlorite was found to be a first order process, using the Coats-Redfern equation, with Delta E = 266 kJ mol(-1). The value of Delta E was nearly equal to the energy required to cleave the Cl-O bond. The gas evolved during the pyrolysis of sodium chlorite wa s identified as O-2 by gas chromatography (GC) and the solid final pro duct was characterized by X-ray diffraction (XRD) as NaCl. A set of fo ur oxides, CuO, ZnO, MnO2 and V2O5 (all from the fourth-period), was u sed as catalysts during the pyrolysis of sodium chlorite. The relation ship between the accelerating effect of such metal oxides, when used a s catalysts, and some factors, such as the valency of the metal atom i n the metal oxide, the metal-oxygen bond and the S-BET of these oxides , has been discussed. V2O5 catalyzed the pyrolysis of sodium chlorite at a very low temperature. Also, it chemically reacted with sodium chl orite in a very exothermic reaction (explosion) between 190-210 degree s C. A reaction scheme was proposed to illustrate the chemical reactio n between V2O5 and sodium chlorite. The reaction intermediates, at 190 and 450 degrees C, of the pyrolysis of sodium chlorite mixed with V2O 5 were identified by XRD and infra-red (IR) analyses.