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

DESIGN OF CATALYTIC SYSTEMS BASED ON THE KINETICCONJUGATION PRINCIPLEL.G. Bruk, A.S. Abdullaeva, E.A. Timashova, E.Yu. Bukina, I.V. Oshanina,O.N. TemkinLomonosov State Academy of Fine Chemical Technology, Moscow, RussiaProspect Vernadskogo, 86, fax: 7(495)434-87-11, E-mail: lbruk@rol.ruOP-I-7The theory of conjugated reactions was developed at the beginning of 20 century and isinteresting now for catalytic systems design. A few conjugated catalytic processes weredesigned by Likholobov’s group on the base of information about probable mechanisms [1].The most interesting one is conjugated oxidation ofcarbon monoxide and water to carbondioxide and hydrogen peroxide, respectively (1)(formally, reaction (1) is result of conjugationexoergic reaction (2) and endoergic one (3).CO + H 2 O + O 2 = CO 2 + H 2 O 2 (1)CO + 1/2O 2 = CO 2 (2)H 2 O + 1/2O 2 = H 2 O 2 (3)The complex of Pd(0) c PPh 3 is the key intermediate in this process [1]. We haveproposed another mechanism for reaction (1), including hydride palladium complex as a keyintermediate (4-6) [2].PdBr 2 + CO + H 2 O → HPdBr + CO 2 + HBr (4)HPdBr + O 2 → BrPdOOH (5)BrPdOOH + HBr → PdBr 2 + H 2 O 2 (6)This mechanism is established for systems PdX 2 -CuBr 2 -solvent (X – Br, I; solvent –1,4-dioxane, tetrahydrofurane). If cyclohexene is added to the system PdBr 2 -CuBr 2 -tetrahydrofurane under reaction (1) conditions (30 0 , atmospheric pressure of CO and O 2mixture), the new conjugated reaction is initiated - hydrocarboxylation of cyclohexene tocyclohexane carboxylic acid. This fact is one of the proofs of mechanism (4-6) correctness,because hydride palladium complexes are the real catalysts of alkenes carbonylationprocesses. Carbonylation of cyclohexene is carried out under more hard conditions withoutconjugation [3]. A number of alkenes were carbonylated in our systems under mildconditions.It is possible to design catalytic systems for reactions with thermodynamic or kineticlimitations using information about probable mechanism of these reactions. We term thisapproach «kinetic conjugation principle of reactions». Problem of selectivity is discussed forconjugated processes. Financial support of RFBR (Grant 08-03-00258).References1. Likholobov V.A., Ermakov Y.I. Kinet. i Kataliz, 1980, 21, 904.2. Bruk L.G., Abdulaeva A.S., Temkin O.N. In: Abstracts 14-th Int. Symp. Homog. Catal. Munich, 2004,P0124.3. Yoshida H., Sugita N., Kudo K., Takezaki Y. Bull. Chem. Soc. Japan, 1976, 49, 8, 2245.39