Synthesis and characterization of catalysts obtained by trifluoromethanesulfonic acid immobilization on zirconia

MARINA GORSD; MIRTA BLANCO; LUIS PIZZIO

Louvain-la-Neuve, Bélgica

Simposio; 10th International Symposium on the "Scientific Bases for the Preparation of Heterogeneous Catalysts; 2010

Mesoporous zirconia (zirconium oxide) materials containing mainly mesopores have been synthesized via sol-gel reactions from zirconium propoxide using urea as a template. The solid was dried, extracted with water to remove urea, calcined at different temperatures and impregnated with trifluoromethanesulfonic acid. The samples thus obtained were extracted with a mixture of dichloromethane and diethyl ether using a Soxhlet apparatus in order to remove the loosely adsorbed acid. The solids were characterized by FT-IR, XRD, DTA-TGA, and N2 adsorption-desorption measurements. The mean pore diameter of the support was higher than 3.7 nm, which increased with the increment of the thermal treatment temperature. At the same time, the specific surface area and the amount of triflic acid attached on the support decreased. The potentiometric titration with n-butylamine indicated that the catalysts present very strong acid sites. The catalytic activity of the prepared catalysts in the esterification of 4-hydroxybenzoic acid with propyl alcohol was evaluated.