Preparation and characterisation of ordered mesoporous SO42-/Al2O3 and its catalytic activity in the conversion of furfuryl alcohol to ethyl levulinate

A series of ordered mesoporous SO42-/Al2O3 (OMSA) solid super acid catalysts were prepared by evaporation-induced self-assembly (EISA) method, followed by sulphonation at different calcination temperatures (400 degrees C-900 degrees C). The results of transmission electron microscopy (TEM) and small-angle X-ray diffraction (XRD) indicated that all of the OMSAs possessed ordered mesoporous structures. The N-2-Brunauer-Emmett-Teller (N-2-BET) results showed that the specific surface area of OMSAs could reach up to 160-380 m(2)/g, and the average pore diameters fall into the range between 8.6 and 9.8 nm. The temperature-programmed desorption of ammonia (NH3-TPD) characterisation proofed that the OMSAs contained super acid, and ammonia desorption by the super acid in the OMSA calcined at 600 degrees C reached 25.9 cm(3)/g STP. The pyridine adsorption infrared (Py-IR) indicated that all of the OMSAs consisted mainly of Lewis acids. The OMSA was used to catalyse furfuryl alcohol in the synthesis of ethyl levulinate (EL). The maximum yield (80.6%) was obtained in the reaction conducted at 200 degrees C for 3 h. The reusability of the catalyst was proofed after four times of reuse as its activity was maintained with a yield of 71.2%.