OP-II-3

PP-I-51ON THE KINETICS AND REGULARITIES OF ETHYLENE GLYCOLOXIDATION INTO GLYOXALSalaev M.A., Kokova D.A., Novikov D.V., Krejker A.A.,Menshchikova T.V., Knyazev A.S., Vodyankina O.V., Kurina L.N.Tomsk state university, Tomsk, Russia, E-mail: mihan555@yandex.ruThe products of alcohol partial oxidation processes are valuable organiccompounds (formaldehyde, acetone, etc). Glyoxal which can be produced byethylene glycol oxidation [1] is a compound with good cross-linking propertiesproviding its various applications. Because of high reactivity and low boiling point ofglyoxal (50,4 °С, [2]) the common methods of experimental kinetic investigation donot allow obtaining correct data. Specifically, the most reliable flow circulating methodis not suitable for kinetic studies of ethylene glycol oxidation because of high processexothermicity and possibility of polymerization and/or polycondensation betweenglyoxal and unreacted ethylene glycol, and other reactive products at elevatedtemperatures. One of the ways to overcome the problems mentioned is kineticstudies in non-isothermal conditions [3].In the present work catalytic activity and kinetic regulations of catalytic systems ofdifferent granularity, representing Cu catalyst, bulk, freshly made and broken-insupported Ag catalysts prepared using sol-gel method mixed with quartz particles,were investigated in a flow fixed bed reactor in the temperature range between 250and 600 °C at constant heating rate and O 2 /(CH 2 OH) 2 molar ratio between 0.8 and1.6. Analysis of gas and liquid products was carried out using GC and HPLCmethods. It was stated that small yields of products can be observed before light-offtemperature was achieved. The main liquid products here were small equal amountsof glyoxal, glycolaldehyde and formaldehyde. This may be an evidence of ethyleneglycol single center adsorption. When light-off temperature was achieved, significantincrease in H 2 and carbon oxides yields, amounting to constant values at optimaltemperatures, was observed. Glyoxal became the predominant liquid product. Smallamounts of glycolaldehyde, formaldehyde, and organic acids were observed.Probably, a double center adsorption of ethylene glycol takes place in thistemperature region. The maximal alcohol conversion and selectivity with respect toglyoxal were observed at elevated temperatures where external diffusion took placewhich was considered to be preferable in comparison with kinetic mode.309