PHYSICO-CHEMICAL AND CATALYTIC CHARACTERISTICS OF SELECTED CATALYSTS FOR CATALYTIC AROMANING OF PROPANE

In the work, the physicochemical and catalytic characteristics of catalysts selected for catalytic aromatization of propane were studied. The conversion of propane was studied at a temperature of 450°C and a pressure of 4 atm. Liquid and gaseous process products were analyzed by gas-liquid chromatography in 40 m long SE-30 capillary columns with helium as the carrier gas. Analysis of X-ray data shows that all synthesized samples have a zeolite structure. There are no reflections in diffraction patterns that do not belong to this structural type, and there is also no strong background characteristic of amorphous mixtures. All these indicate the high phase purity of the obtained materials. In contrast to the 2%Cu*2%Zn/H-YUKS-30 sample, the crystalline spirit oxide phase is observed in 2%Cu*8%Zn/H-YUKS-30 and 8%Zn/silicalites . It was possible to prepare a number of samples by mechanical displacement of 0.5-5% ZnO with H-YUKS-30 and establish a correlation between the reflection intensity at 2θ=36.4°С and the composition of ZnO crystals in these samples. A comparison of the initial rate of conversion of propane to aromatic hydrocarbons in spirit-containing and acidic high-silica mesoporous zeolites showed that modification with spirit leads to a significant increase in catalyst activity at the initial stages of conversion. No correlation was found between the initial velocities and the concentration of acid centers. On the contrary, a linear correlation was observed with the number of Lewis acid centers. Thus, it was shown that in the initial stages of conversion of propane to aromatic hydrocarbons, the main role is played by L-centers, which include alcohol.