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

PP-III-49FIBROUS PALLADIUM-SUPPORTED CATALYSTSFOR REACTION OF HYDROGEN OXIDATIONRadkevich V.Z., Senko T.L., Shunkevich A.A., Yegiazarov Yu.G.Institute of Physical-Organic Chemistry of the National Academy of Science of Belarus,Minsk, Fax: 375-172-841-679, e-mail: radkevich_vz@ifoch.bas-net.byNew methods of synthesis of fibrous ion-exchangers have been developed in our institutefor ceveral decades. These ion-exchangers find a use in many fields of application, includingcatalysis. One of the advantages of these materials is possibility of their use in systems withlow hydraulic resistance, in slot reactors for instance. Low fiber diameter (ten times lowerthen granule diameter) determines higher rate of mass-exchange processes and, as a result,higher rate of whole process.Current work deals with preparation of palladium supported catalysts on the basis offibrous ion-exchangers. Effect of ion-exchanger composition on the degree of reduction ofpalladium, dispersion and catalytic activity of supported metal in the reaction of hydrogenoxidation was investigated.As supports for palladium-containing catalysts various fibrous ion-exchangers werechosen: sulphocationite FIBAN K-1 in H- and Ba-forms, carboxylic cation-exchanger FIBANK-4, anion-exchangers FIBAN A-1, FIBAN AK-22-1, FIBAN A-5 and FIBAN A-6 andpolyampholyte FIBAN AK-22-B. Monofunctional ion-exchangers (strong acidicsulphocationite FIBAN K-1 and strong basic anionite FIBAN A-1) were synthesised on thebasis of polypropylene (PP) with grafted styrenedivinylbenzene copolymer, FIBAN K-4 – onthe basis of PP with grafted polyacrylic acid, anionites FIBAN A-1, FIBAN AK-22-1, FIBANA-5 and FIBAN A-6 and polyampholyte FIBAN AK-22-B – on the basis of polyacrylonitrilicfibers.Palladium-containing catalysts were prepared by means of ion-exchange under staticconditions and at room temperature. Ion-exchange was conducted by treatment ofsulphocationites and carboxylic cation-exchangers with aqueous solutions of [Pd(NH 3 ) 4 ]Cl 2and by treatment of anionites with muriatic aqueous solutions of PdCl 2 . Supported palladiumwas reduced by treatment of ion-exchanged sumples with hydrazine (aqueous solution) ormolecular hydrogen. Degree of reduction Pd 2+ to Pd o in catalysts (α Pd ) was determinedaccording to difference of quantity of ion-exchange palladium in sample before and afterreduction measured by means of atomic emission spectroscopy. Metal particles size inreduced samples was measured by means of electron microscopy.394