COMPOSITION, PHYSICOCHEMICAL PROPERTIES, AND CATALYTIC PROPERTIES OF THE PRODUCTS OF THERMAL-TREATMENT OF AL-2(SO4)(3)CENTER-DOT-18H(2)O

The influence of the conditions of thermal treatment of Al-2(SO4)(3). 18H(2)O on the properties of the products formed is studied by a compl ex of physicochemical methods. The catalytic activity of these product s in the model reactions of L-butene isomerization into 2-butenes and dehydration of isobutanol is investigated. It is shown by Al-27 MAS NM R that the coordination sphere of aluminum changes upon calcination: w ater molecules are substituted by hydroxyl and sulfate groups. The pro cesses of hydrolysis and condensation of AlOH and SOH groups leading t o the substitution of all ligands by the sulfate groups are stopped at temperatures below 250 degrees C. The specific surface area and catal ytic activity of aluminum sulfates in the reactions under study are go verned by the conditions of thermal treatment. The sample of anhydrous crystalline Al-2(SO4)(3) calcined at 400-450 degrees C exhibits the h ighest catalytic activity.