Titanyl sulfate extracted from the mineral ilmenite as mesoporous catalyst for the oleic acid esterification

Titanyl sulfate (TiOSO4) extracted with sulfuric acid from the mineral ilmenite (FeTiO3), which has a high content of titanium (32.2 wt.%) was study as acid solid catalyst for the oleic acid esterification. The maximum extraction of Ti was 98 wt.%. As reference catalysts sulfated titania (SO42-–TiO2) and titania (TiO2) were synthesized by sol–gel route using as starting precursor titanyl sulfate. Characterization by XRD, XRF, FT-IR and nitrogen adsorption was made on calcined samples at 673 and 923 K. The acid strength and number of acid sites of the solids were determinate by potentiometric titration with n-butylamine. The catalytic activity of the characterized solids was evaluated in the esterification of oleic acid (79 wt.%) with ethanol at 353 K using an oleic acid:ethanol molar ratio of 1:10. Titanyl sulfate (673 K) catalyst under such reaction conditions and without additional treatments showed to be more active (86%) than sulfated titania (64%).

Mesoporous sulfated titania catalyst for the esterification reaction of free fatty acids has been synthesized by the sol–gel route using as starting precursor titanyl sulfate extracted from the mineral ilmenite (FeTiO3).Figure optionsDownload as PowerPoint slideHighlights
► Titanyl sulfate extraction from the mineral ilmenite.
► Strong acidity on titanyl sulfate.
► Titanyl sulfate is a very efficient acid solid catalyst.