Boreskov Institute of Catalysis of the Siberian Branch of Russian ...

PP-I-13ab1,01,0Isotope fraction0,5[zA]ABIsotope fraction0,5BAIsotope fraction1,00,5B*B0,00,0 0,5 1,0Bed lenght0,0t 1Time0,0TimeFig. 1. Variation of isotope fractions in reactants, adspecies and reaction product along the catalyst bed at timepoint t 1 (a) and their temporal dependencies at the reactor outlet (b) as calculated in accordance with schemesA↔[zA]→B and A 2 ↔2[zA]→B 2 (insert). Dotted line shows isotope fraction of BB* corresponding to binomialdistribution.Such effects were observed by us in the reaction of NO selective reduction by methane(NO+CH 4 +O 2 →N 2 +CO 2 +H 2 O). At the initial period of time after 14 NO replacement by 15 NOlabel fraction in N 2 was higher than in NO, while 14 N 15 N concentration was substantiallylower than it should be in the case of binomial distribution. Using of proper models of isotopetransfer accounting for change of isotope concentration with reactor length both in gas phasereagents and adspecies allowed description of isotope responses, elucidation of the scheme ofreaction mechanism and estimation of both reactions coefficients, and their activationenergies [3].References1. Shannon S., Goodvin J. // Chem. Rev. 1995. V. 95. № 3. P. 679.2. E.M. Sadovskaya, D.A. Bulushev and B.S. Bal’zhinimaev, Kin. and Catal., 40 (1999) 61.3. Sadovskaya E.M. et all. // J. Catal. 225 (2004) P. 179.236