ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Mesoporous phosphated and sulphated silica as solid acid catalysts for glycerol acetylation

Khadijeh Beigom Ghoreishi, Nilofar Asim, Mohd Ambar Yarmo, and Mohd Wahid Samsudin

School of Chemical Science and Food Technology, Faculty of Science and Technology, University Kebangsaan Malaysia (UKM), 43600, Bangi, Selangor Darul Ehsan, Malaysia

E-mail: khadijehbeigom@siswa.ukm.edu.my

Abstract: Sulphate- and phosphate-loaded silicas were synthesised using the sol-gel method with different sulphate and phosphate loadings. These catalysts were characterised using Fourier transform infrared spectroscopy (FT-IR), the Brunauer-Emmett-Teller (BET) method and X-ray photoelectron spectroscopy (XPS). Acidity was measured using the temperature-programmed desorption of ammonia (TPD-NH3) method. The results showed that glycerol esterification with acetic acid conversion decreased as follows: α(H₂SO₄) (100 %) > α(H₃PO₄) (99 %) > α(silica loaded with 20 % sulphuric acid) (SS-20; 98 %) > α(silica loaded with 20 % phosphoric acid) (PS-20; 83 %). These studies suggest that the solid acid catalytic activity in the esterification of glycerol is highly dependent on catalyst acidity strength, pore size and surface area.

Keywords: glycerol – acetylation – sulphated silica – phosphated silica – sol-gel – mesoporous

Full paper is available at www.springerlink.com.

DOI: 10.2478/s11696-014-0550-x

Chemical Papers 68 (9) 1194–1204 (2014)