Synthesis, characterization and modification of hydroxyapatite with zinc for application in the esterification reaction

ABSTRACT Hydroxyapatite has stood out among the ceramic materials due to their structural versatility as it allows the replacement of Ca2 + or PO43-its structure enabling various applications. One area that is gaining prominence is the application of hydroxyapatite as support and or catalyst. Thus, the objective of this work was the synthesis, modification and characterization of hydroxyapatite for use as a catalyst in esterification reaction. The hydroxyapatite was obtained by the precipitation method and was modified by solid state ion-exchange method using Zn(NO3)2 as precursor. The resulting ceramics were characterized by thermal analysis, Fourier Transform Infrared Spectroscopy, X-ray diffraction and Bronsted acidity test. The catalysts HAP and Zn-HAP prepared were evaluated against the esterification reaction of oleic acid with methanol under the following reaction conditions: ratio methanol: oleic acid (20:1), 10% m/m of catalyst and 3h reaction at 150 °C showing conversions of 16.9% and 37.0%, respectively. These results are interesting, mainly from the economical point of view, since they are low cost materials used as support for heterogeneous catalysts.