abstracts - Институт катализа им. Г.К. Борескова

- process (3) can be important in the case of developed chain reaction;KS-I-2- in the presence of catalyst reactions (2) and (4) are the main sources of propylene, whereasin post-catalyst void volume additional amount of C 3= can form via reactions (2) and (3).3. At low concentrations of oxygen ethylene can form via "anaerobic" processC 3 H 7 → C 2 H 4 + CH 3 (5)which is likely to proceed in parallel with (1) when the formation of equal amounts of C 3= ,C 2= and methane is observed. At higher O 2 concentration the reversible formation of propylperoxyradicals in parallel with reaction (2) becomes important. The consecutivetransformations of C 3 H 7 O 2 lead to the formation of C 2= and carbon oxides.4. Effects of CO 2 addition and downstream void volume suggest the possibility ofheterogeneous C 2= formation in parallel with total oxidation, for instance[O] S + C 3 H 7 → [OC 3 H 7 ] S → [OCH 3 ] S + C 2 H 4 (6)↓CO X + H 2 OAlso, additional cracking of propyl radicals can take place over low-coordination sitesactively poisoned by CO 2 .Effects of reaction conditions and properties of catalyst active sites upon the ratio of therates of formation of n- and iso-propyl radicals, as well as the difference in the reactivities ofthe latter in consecutive reactions towards dehydrogenation (C 3= ) and cracking products (C 2= ,methane) are discussed. It is shown that the increase of H-atom affinity of surface active sitesshould result in the shift to a more efficient formation of n-C 3 H 7 . In their turn, the latter arelikely to be more efficient in some reactions leading to the formation of cracking products.The financial support from AURUS Marketing-Service GmbH is appreciatedReferences:1 K.T. Nguyen, H.H. Kung. J. Catal., 122 (1990) 415.2 V.P. Vislovskiy, T.E. Suleimanov, M.Yu. Sinev, Yu.P. Tulenin, L.Ya. Margolis,V. Cortés Corberán. Catal. Today, 61 (2000) 287.3 D.J. Driscoll, W. Martir, J.H. Lunsford. J. Phys. Chem.. 89 (1985) 4415.4 M.Yu. Sinev. Catal. Today, 13 (1992) 561; ibid. 24 (1995) 389.27