Metathesis of 2-butene to propylene over W-mesoporous molecular sieves: A comparative study between tungsten containing MCM-41 and SBA-15

Abstract Mesoporous silica( MCM-41and SBA-15) having tungstenoxide in the framework was synthesized by hydrothermal crystallization process using CTAB and P123 as structure directing agents, respectively. Tungstenoxide was supported on the MCM-41and SBA-15 by wet impregnation method for a comparative study. The synthesized materials were characterized by XRD, N 2 adsorption–desorption, NH 3 -TPD, pyridine-FT-IR, UV–vis DRS and Raman spectroscopy techniques. The catalysts were used to perform metathesisreaction of 2-butenein a fixed-bed reactor at different temperatures and under atmospheric pressure. It was observed that catalysts having tungstenoxide in the framework of mesoporous silicaexhibited higher activity as compared to tungstenoxide impregnated catalysts. The results revealed that WO 3 - MCM-41(30) catalyst has much higher activity at a low temperature (450 °C) as compared to WO 3 -SBA-15(30). At 550 °C, WO 3 - MCM-41(30) and WO 3 -SBA-15(30) showed comparable activity with highest propylene yield of 39 mol% and 37 mol%, respectively. The higher metathesisactivity of WO 3 - MCM-41catalysts can be related to the well-dispersed active tetrahedral tungstenoxide species as evidenced from XRD, UV–vis DRS and Raman spectroscopy results.