Role of Brønsted and Lewis acidic sites in sulfonated Zr-MCM-41 for the catalytic reaction of cellulose into 5-hydroxymethyl furfural

Abstract

A series of sulfonated Zr-MCM-41 samples were synthesized by the in-situ method followed by sulfonation using sulfuric acid for the catalytic study of cellulose to 5-hydroxymethyl furfural in batch condition. All synthesized catalysts were characterized by XRD, N2 adsorption–desorption isotherm, FT-IR, TEM, EDX, and NH3 temperature-programmed desorption analysis. The XRD and N2 adsorption–desorption isotherm results have confirmed that incorporated Zr4+ was substituted within the framework of silica MCM-41 with hexagonal pores. Similarly, the FT-IR and EDX results have proved that Zr-MCM-41 was sulfonated. The Brønsted acidic and Lewis acidic sites were identified by NH3-TPD analysis. Among the sulfonated Zr-MCM-41 catalysts, S-15Zr-MCM-41 has shown 70% cellulose conversion with 16.4% selectivity of 5-hydroxymethyl furfural at 170 °C for 2 h which was higher than other catalysts. It was attributed to the high ratio of Brønsted acidic to Lewis acidic sites. Graphic abstract: [Figure not available: see fulltext.]