III International Conference

PP-I-12The nanostructure of CS (clusters of salt) in C1, C2, C3 catalysts includes both saltclusters with wide size distribution and located in micropores highly dispersed SC states as isseen from fig. 2. It is characteristic of C1 to form large clusters of SC of considerable volumewhile their number in C2 is significantly lower. As for C3, close to molecular dispersion of0.90.80.70.60.50.40.30.20.1lg (ΔV/ΔR)ml⋅g -1 ⋅Å -12100 1 2 3lg R (Å)Fig.1 Differential curves of pore sizedistribution of AC modified with Н 2 О 2 (S2)and initial (S1) as to the benzene vapouradsorption isotherms.4321R, ? .Fig.2 Differential curves of micropores sizedistribution and cluster of salt of catalystsC1-(1), C2-(2) and C3-(3).SC is observed, the volume of salt clusters being further lowered . Besides, based on SEMand XMA data a considerable scattering of zinc acetate content onto several surface sites ischaracteristic for C1 which is indicative of immobilization of different zinc containingvarieties forming disordered nonstoichiometric states of SC. The approximate equality of zincconcentration onto C3 surface demonstrates the more uniform microdistribution of SC.As follows from these facts the activity of C2 and especially of C3 in vinyl acetate (VA)synthesis is 5-6 times that of C1. Thus at 175, 205 and 230°C the efficiency of C3 sample asfor VA is as much as 42,5; 198 and 342 g·l -1·h -1 , characteristics of C3 being more stable thanthose of C1 after three cycles of temperature alteration.To conclude with, the use of modified by hydrogen peroxide oxidation AC support underconditions of slow drying may yield a stable and active catalyst for hydroacetoxylation ofacetylene.References1. Kurlyandskaya I.I., Glazunova E.D., Temkin O.N. and Hoang Kim Bong // Thesis at Internationalsymposium “Carbon for catalysis” (Carbocat-2004, July 18-20, 2004) Lausanne, Switzerland,p.225.2. Kurlyandskaya I.I., Glazunova E.D., Temkin O.N., Hoang Kim Bong, Plavnik G.M. andObolonkova E.S.// Thesis at VI Russian conference of catalysis reactions mexanism//Novosibirsk, 2002, p.111.3. Hoang Kim Bong, I. Abanto Chavez, A.N. Nyrkova and O.N.Temkin. // Russian Journal ofApplied Chemistry, 1998, V.71, № 1, p.92.30