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

PP-IV-24From the data displayed in Fig. 2, one can see that the composition of the zeoliteframework and the gallium concentration in the catalyst significantly affected the yield ofliquid products. The galloaluminosilicate with M = 60 had the highest catalytic activity innatural gas conversion. The aromatic hydrocarbon yield at 600 °C and 1000 h –1 reached18.7% with a conversion of 26.0%.Conversion, Ar-C yield, %3025201510500 550 600 650Temperature, о С4536121086420Product yield, %Conversion, yield, %3025201510501,2%Ga/M=30Conversion1,2%Ga/M=401,2% Ga/M=601,2% Ga/M=802,2% Ga/M=30Yield2,2% Ga/M=402,2% Ga/M=602,2% Ga/M=80Fig. 1. (1) Conversion of natural gas on 2.2% Ga-AS(M = 60) and (2-6) yield of (2) benzene, (3) toluene, (4)naphthalene, (5) Ar-C 11-12 , and (6) Ar-C 6+ versusprocess temperature (W = 1000 h –1 ).Fig. 2. Natural gas conversion and aromatichydrocarbon yield over galloaluminosilicates withdifferent silica ratios and different gallium oxideconcentrations (T = 600 °C, W = 1000 h –1 ).This evolution of the catalytic properties of galloaluminosilicates during natural gasconversion is due to the fact that the aluminum concentration decreases with increasing silicaratio, thus increasing the ratio between the Lewis and BrØnsted acid sites on the catalyst. Inaddition, gallium doping generates new strong aprotic acid sites in the zeolite, while thedensity of protic acid sites, which are associated with lattice aluminum, decreases.Thus, galloaluminosilicates have a high catalytic activity in natural gas conversion toaromatic hydrocarbons. The most active catalysts have the silica ratio equal to 30 or 60 andcontain 1.2 or 2.2 wt % gallium oxide, respectively. These catalytic systems make it possibleto carry out the chemical conversion of gaseous hydrocarbons to liquid products in one stage;thus, the in addition make it possible to produce valuable organic compounds from alternativesources for use in petrochemical and chemical industries.References1. Kuznetsov B.N. Motor fuels from alternative sources // Sorovsk. Obrazovat. Zh. 2000. Vol. 6. № 4. P. 51.2. Rozovskii A.Ya. Synthesis of motor fuels from natural gas // Khim. Prom-st. 2000. № 3. P. 3.439