THE SELECTIVE REDUCTION OF NITROGEN-OXIDES BY HIGHER HYDROCARBONS ON PT CATALYSTS UNDERLEAN-BURN CONDITIONS

The selective reduction of nitrogen oxide by various hydrocarbons has been investigated with alumina-and silica-supported Pt catalysts. Sign ificant variations are observed in the effectiveness of the reductant, with n-paraffins being the most effective and iso-paraffins the least effective for alumina-supported catalysts. Silica-supported catalysts show higher activities, especially with iso-paraffins. n-paraffins ar e found to be effective at low temperatures whereas toluene is more ef fective at higher temperatures. Particle size effects for alumina-supp orted catalysts do not appear to have much influence for the reactions involving toluene. An interesting feature is the absence of nitrous o xide formation when toluene is used as the reductant.