Synthesis, characterization and catalytic behavior of SnTf/MCM-41 and SnTf/UVM-7 as new green catalysts for etherification reactions

Strong Lewis acid SnTf-MCM-41 and SnTf-UVM-7 catalysts with unimodal and bimodal pore systems were prepared in a two-step synthesis in which the triflic acid (OTf) was incorporated into previously synthesized mesoporous tin-containing silicas. The Sn incorporation inside the pore walls was carried out through the Atrane method. The SnTf-UVM-7 catalysts were prepared by aggregating nanometric mesoporous particles defining a hierarchic textural-type additional pore system. Catalysts with different Si/Sn ratios in the range 21.8–50.8 for SnTf-MCM-41 and 18.4 for SnTf-UVM-7 were found to be efficient catalysts for the etherification of primary alcohols to symmetrical long chain ethers and the selective etherification of ethylene glycol with 1-octanol to nonionic surfactants structures. The processes are green, environmentally safe, and heterogeneous.