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Counter anions of active components on catalysts were found to affect catalytic activities for NO reduction with NH3. Halide ions promoted activity in copper and iron catalysts, but lowered it in chromium and manganese catalysts. The most favorable electronic state of a cation on catalysts was investigated by changing counter anions and/or carriers.

The activity of silica-alumina catalyst in the isomerization of m-xylene was measured at the temperatures of 290°C, 320°C, 380°C, and 430°C in the liquid phase under a pressure of 300 kg/cm2. The observed activities were considerably higher than those in vapor-phase reactions, moreover even after 20 days practically no decline in the activity was observed except for the measurements at 430°C. This superior ability of the catalyst in the liquid phase can be ascribed to the cleaning effect of the liquid reactant: in the liquid-phase reaction the high-boiling by-product, which, in vapor-phase reactions, diminishes the activity because of its strong adsorptivity on the surface sites, is successively dissolved in the reactant; therefore, more surface sites are constantly available for the isomerization. This interpretation was substantiated by the following results: 1) when the reaction was operated in the liquid phase, about eighteen times as much high-boiling by-product was obtained as in the vapor phase; 2) the activity in the liquid-phase reaction was much higher than that in the vapor phase; 3) the decreased activity caused by the interruption of the flow was regenerable when the flow was resumed; 4) the addition of the high-boiling by-product to the reactant m-xylene resulted in a considerable decrease in the activity. In addition, the identification of the components in the high-boiling by-products was carried out by means of mass and NMR spectroscopic studies.

When nitric oxide was admitted during the course of the reduction of N2O by CO, a discontinuous increase in the N2O pressure and a decrease in the NO pressure were observed. The reduction of N2O stopped completely, and only the reduction of NO to N2O proceeded.