Transesterification of oil by sulfated Zr-supported mesoporous silica

Abstract

Highly dispersed sulfated zirconia has been successfully supported on SBA-15 using a postsynthesis method (P-SZS) and compared with conventional sulfated zirconia (SZ) in terms of catalytic activity in the transesterification of palm oil. The synthesized catalysts were characterized by XRD, TEM, NH 3 TPD, and N2 adsorption-desorption measurements. The P-SZS catalysts could retain the ordered mesoporous hexagonal structure even at very high Zr loadings, and they had higher acidities (i.e., higher amounts of acid sites and higher acid strengths) than SZ because of the interaction of the highly dispersed sulfated zirconia with the large surface area of SBA-15. As a result, P-SZS catalysts have higher catalytic activities than SZ catalyst for the transesterification of palm oil with methanol. A series of P-SZS catalysts with varying amounts of sulfated zirconia were synthesized. P-SZS-1, which had the highest amount of supported sulfated zirconia, showed the best catalytic performance for transesterification reaction. The activity and stability of P-SZS-1 catalyst could be maintained, as the used P-SZS-1 catalyst could be regenerated simply by resulfation of the catalytic sites without the destruction of the ordered mesoporous structure. Interestingly, P-SZS-1 catalyst could be recycled and reused for at least five cycles without significant decrease in activity and stability. © 2011 American Chemical Society.