Synthesis And Properties Of A New Kind Of Mesoporous Solid Acid Catalysts

In comparision with liquid acid catalysts, solid acid catalysts have the advantages of no corrosion, high selectivity, easy separation, etc.In this work, a new kind of mesoporous solid acid catalysts having shape selectivity, high stability and high acid density were synthesized. The preparation process involves four steps: (1) preparation of mesoporous (Al)MCM-41 through hydrothermal synthesis using C16TMABr as template and TEOS as silica source under basic conditions; (2) polymerization of furfuryl alcohol into a film on the mesopores of (Al)MCM-41 obtained in step 1; (3) carbonization of the polyfurfuryl acohol film obtained in step 2; (4) sulfonation of the carbonized polyfurfuryl alcohol film in (Al)MCM-41 obtained in step 3. Effects of the sequence of Al addition, carbonization temperature, sulfonation temperature on the mesoporous solid acid catalysts were studied. The mesoporous solid acid catalysts as well as the intermediates in the synthesis were characterized by XRD, BET, IR, XPS, TPD, TEM, etc.The characterization results showed that the mesoporous solid acid catalysts were typical mesoporous; -HSO3 was successfully introduced onto the surface of the mesoporous materials; the catalysts mid-strong acids with acid denstities ranging from 0.747 to 2.14 mmol/g.The reaction results showed that the catalysts were very active and had high selectivity in the esterification of acetic acid and ethanol. The catalyst with 2.14 mmol/g H+, prepared under the optimized conditions, i.e., Al-MCM-41 mesoporous with pore size 6.68nm, polymerization of furfuryl alcohol at 80°C for 3h and treated with concentrated H2SO4 at 200°C for 15h, exhibited 92.1% conversion of acetate acid with 100% selectivity to ethyl acetate after reaction at 70°C for 7 h.