Temperature effect on the physicochemical properties of χ-alumina interaction with CCl4

Abstract

Abstract The main characteristics in the formation of morphological, textural and acidic properties of the catalysts obtained by thermal treatment of χ-Al2O3 in a flow of carbon tetrachloride over the temperature range of 200 - 500°C were revealed. It was found that the sorption capacity of χ-χ-Al2O3 with respect to chloride ion depends nonlinearly on the temperature of interaction with CCl4. The sorption capacity increases when the temperature is raised from 200 to 400°C, and then decreases with the temperature elevation to 500°C due to an increase in the formation rate of aluminum chloride and high volatility of bulk AlCl3. The analysis of some models describing the sorption kinetics of chloride ions on χ-Al2O3 revealed that experimental data obtained at 200 and 300°C are well approximated within the pseudo-second order model. The calculated parameters of thermodynamic models (Langmuir, Freundlich, Temkin and Dubinin- Radushkevich) showed that the chlorination of χ-Al2O3 with carbon tetrachloride proceeds by the chemisorption mechanism. The observed characteristics in the formation of main physicochemical properties are caused by the chemistry of reactions proceeding on the surface and in the bulk of χ-Al2O3 particles upon interaction with carbon tetrachloride.