Comparison of acid sulfonic mesostructured silicas for 1-butylacetate synthesis

Ordered mesoporous silicas MCM-41, HMS, SBA-15 (hexagonal), and MCM-48 (cubic) have been synthesized and functionalized with propylsulfonic acid groups by post-oxidation method. Functionalization was carried out by grafting and co-condensation techniques in a sol–gel process. This process required TEOS, MPTS and an appropriate surfactant as structure-directing agent. Synthesis methods were modified and adapted specifically from literature for each case. The materials were characterized by XRD, TGA, FT-IR, and SEM. The catalytic activity was tested over the esterification reaction to produce 1-butylacetate. The effects of mesophase and functionalization technique were related to the catalytic performance. The higher functionalization was reached by co-condensation technique, and the best ratio between catalytic performance and functionalization degree was exhibited by SBA-15, followed by MCM-41, HMS and MCM-48 in decreasing order. Substantial differences in catalytic activity were found for materials with hexagonal and cubic mesophase.