CONVERSION OF NITROGEN-DIOXIDE, NITRIC-ACID, AND NORMAL-PROPYL NITRATE TO NITRIC-OXIDE BY GOLD-CATALYZED REDUCTION WITH CARBON-MONOXIDE

A new technique is described for the real-time, quantitative conversion of several XNO//2 compounds to NO, where X denotes a radical group. The technique utilizes the reduction of these compounds by CO at a heated gold catalyst to yield NO. The NO product was detected by a sensitive chemiluminescence detector. The technique was demonstrated to convert NO//2, HNO//3, and n-propyl nitrate quantitatively to NO for mixing ratios in the range of 1-120 ppbv in synthetic air at atmospheric pressure. Conversion results were obtained for CO mixing ratios in the range of 0. 2-1000 ppmv and for temperatures in the range of 20-600 degree C. The Gormley-Kennedy equation was used to analyze the results for consistency with known diffusion coefficients. The Co reduction process is discussed in terms of the thermochemistry of the net conversion reactions and catalytic properties of the gold surface.