Modification of turen's bentonite with AlCl3 for esterification of palmitic acid

Natural Turen's bentonite has been purified, modified and applied as catalyst for palmitic acid esterifi-cation. Modification of natural Turen's bentonite was conducted by cation exchange method using AlCl3 solution. Catalyst characterization was performed on X-ray Fluorescence, X-ray Diffraction, ni-trogen adsorption-desorption and infrared spectroscopy techniques. The catalytic activity test in the es-terification reaction of palmitic acid with methanol was conducted by bath at 65 °C with a variation of reaction time of 1, 2, 3, 4 and 5 h. Catalytic activity has been observed qualitatively using GC-MS and quantitatively by changes in acid number. The analysis showed the formation of Al³⁺-bentonite. Obser-vation on the elements has shown that the presence of calcium decreased from 10.2 to 4.17 %, with an increase of aluminium content from 9.9 to 13 %. Diffraction line at 2θ 5.7379° became 5.6489°, along with changes in d-spacing of 15.3895 to 15.6319 Å. The surface area increased from 83.78 to 91.26 m²/g, while Br̈nsted acid sites increased from 10.2 to 67.5 μmol/g and Lewis acid sites increased from 94.9 to 132 μmol/g. Furthermore, Al³⁺- bentonite has showed as active catalyst in the esterification re-action of palmitic acid with palmitic acid with conversion of 78.78 % for 7 h.