Dehydrative etherification of carbohydrates to 5-ethoxymethylfurfural over SBA-15-supported Sn-modified heteropolysilicate catalysts†
Dehydration followed by the alcoholysis of glucose/fructose to 5-ethoxymethylfurfural (EMF) was carried out over SBA-15-supported tin-modified heteropolysilicate (SnSTA) catalysts. The physico-chemical properties of the catalysts were explored by X-ray diffraction, Fourier-transform infrared spectroscopy (FT-IR), pyridine-adsorbed FT-IR spectroscopy, transmission electron microscopy (TEM), N2 physisorption, laser Raman and NH3 temperature-programmed desorption techniques. The characterization results confirmed that the Sn-exchanged STA species were productively embedded inside the pores of SBA-15 without disturbing the parent hexagonal structure. High conversion and selectivity towards EMF were achieved with 20 wt% Sn0.75STA on SBA-15. The high activity of the catalyst could be attributed to the well-dispersed intact Keggin Sn0.75STA on the support, which led to the generation of sufficient Brønsted and Lewis acidic sites. The influence of various reaction parameters such as catalyst weight, reaction temperature, and time was studied along with the stability and reusability of the catalyst.