CATALYTIC COMBUSTION OF HYDROCARBONS. 4. EFFECT OF PREPARATION METHOD ON CATALYTIC ACTIVITY

Five types of CuO catalysts were prepared in this study by varying the amount of KOH used in the precipitation of CuOH2 from aqueous CuNO32 solutions. The rate of the catalytic combustion of ethylene was used as a measure of the activity of these catalysts. Overall rate expressions of the form rKP sub E to the nth power were used to correlate the experimental data. An average reaction order of 0.60 provided the best correlation of all the kinetic data. The experimental data indicated that the temperature required for a given conversion decreased with increasing amounts of KOH used in the preparation of the catalyst up to 25 per cent greater than stoichiometric. The BET surface area and mechanical strength of the catalyst increased with increasing KOH used. Using the specific rate constant per unit surface area as a measure of activity it was found that the catalytic activity of CuO decreased with increasing pH or amount of KOH used. Comparison of the activity of the stoichiometric catalyst prepared in this investigation with the activity of cupric oxide-alumina 11 catalyst studied by Accomazzo for the same reaction proved greatly in favor of pure CuO.