III International Conference

PP-I-13СО ISOTOPIC EXCHANGE OVER Rh/Al 2 O 3 : NONDISSOCIATIVE EXCHANGEON METALLIC Rh SITESBreyeva N.V., Zhavoronkova K.N.D.I. Mendeleyev University of Сhemical Тechnology, Moscow, Russiae-mail:n_breeva@mail.ruThe isotopic exchange reaction 12 C 18 C+ 13 C 16 O= 13 C 18 O+ 12 C 16 O has been studied overalumina-supported rhodium catalysts 0.1%Rh/γ-Al 2 O 3 , 1%Rh/γ-Al 2 O 3 , 5%Rh/γ-Al 2 O 3 ,10%Rh/γ-Al 2 O 3 and γ-Al 2 O 3 at temperatures 173-583 K.Since preparations, enrichment of heavy isotopes of carbon 13 С became accessible,researchers were involved with studying reaction of an isotope exchange in molecules СО:12 C 18 C+ 13 C 16 O= 13 C 18 O+ 12 C 16 O.It is connected first of all with that the given reaction allows to obtain additional data oninteraction of adsorbed СО with a surface of catalysts and on the mechanism of suchimportant catalytic reactions as СО water steam conversion, СО hydrogenation, reaction ofСО oxidation.The isotopic exchange reaction 12 C 18 C+ 13 C 16 O= 13 C 18 O+ 12 C 16 O has been studied overalumina-supported rhodium catalysts: 0.1%Rh/γ-Al 2 O 3 , 1%Rh/γ-Al 2 O 3, 5%Rh/γ-Al 2 O 3 ,10%Rh/γ-Al 2 O 3 and γ-Al 2 O 3 at temperatures 173-583 K. Catalysts (0.1%Rh/γ-Al 2 O 3 ,1%Rh/γ-Al 2 O 3 , 5%Rh/γ-Al 2 O 3 , 10%Rh/γ-Al 2 O) were prepared by impregnation by a moisturecapacity of γ-Al 2 O 3 with water solution of rhodium nitrate of mark ch. with the subsequentkeeping of damp granules within a day, drying at 110 o С and heat treatment at 500 o С during2 hours. Catalysts before testing of isotope equilibration were restored in hydrogen at 200 o Сand subjected to standard vacuum processing: exhaustion at temperature 400 o С up to residualpressure 10 -6 Torr. The sample was exposed to such processing before measurement at eachtemperature, in order to prevent distortion of results owing to influence of СО on surfaceproperties. Thus, each measurement was spent on exposed surfaces.Following features of isotopic mixing on the given catalysts are established:1. On the low-percentage catalyst and on the pure carrier 2 areas of course of anexchange: low- temperature and high-temperature are observed.2. On 5%Rh/γ-Al 2 O 3 low- temperature area is expressed much more poorly, than on1%Rh/γ-Al 2 O 3 .3. On 10%Rh/γ-Al 2 O 3 low-temperature area is absent.31