Production of copper/zinc catalysts from malahite ore containing zinc

In this study, CuO/ZnO catalysts were synthesized for use in the single-stage liquid phase oxidation reaction of benzene to phenol. Malachite a copper ore, which also contains zinc, was leached to take copper and zinc into the solution as ions and their leaching kinetics was investigated. Ammonia/ammonium nitrate concentration (C), particle size (TB), solid/liquid ratio (K/S), mixing speed (KH) and reaction temperature (T) were chosen as independent parameters. It was determined that the decrease in solid size and solid/liquid ratio, increase in reaction temperature and solution concentration increased the leaching rate. The rate expression of the leaching reaction was represented by a mixed kinetic model. The activation energy for the dissolution reaction of both copper and zinc ions was found to be 16.22 kJ/mol. The model equation for leaching process is expressed as follows for copper and zinc ions, respectively. 〖〖[1-(1-X_Cu)〗^(1/3)]〗^2=5.3.10^(-7) (C)^(1.5949 ).(TB)^(-1.0101) .(K/S)^(-0.679).(KH)^0.5647.exp((-1951)/T).t 〖〖[1-(1-X_Zn)〗^(1/3)]〗^2=1.35.10^(-10) (C)^(0.3692 ).(TB)^(-0.7533) .(K/S)^(-0.2461).(KH)^2.0649.exp((-1950.7)/T).t Precipitation of copper and zinc ions in the form of carbonate compounds was achieved by co-precipitation using the leach solution. Cu/Zn catalyst in oxide form was prepared by the calcination of the precipitate of the carbonate compound. XRD, BET, SEM-EDS, TGA-DTA, FT-IR analysis techniques were applied for the structural characterization of the binary CuO/ZnO catalyst. Activity tests of the catalysts for single-step oxidation reaction of benzene to phenol was carried out in liquid phase. Ascorbic acid concentration, amount of catalyst, reaction time, stirring speed, benzene concentration and reaction temperature were chosen as independent parameters. It was determined that the catalyst prepared for his study had a better activity compared to the catalysts mentioned in the literature, Maximum phenol yield was calculated as 3.23 % under optimum conditions. The production of phenol from benzene was found to fit the first-order kinetic model. The activation energy of the reaction was found to be 7.09 kJ/mol.