Silica-poly(styrenesulphonic acid) nanocomposites as promising acid catalysts

• Published in: Catalysis today 2017-01, Vol.279, p.155-163
• Main Authors: Campos-Molina, M.J., Corral-Pérez, J.J., Mariscal, R., Granados, M. López
• Format: Article
• Language: English
• Subjects: Biodiesel; Furfural; Polymer-SiO2 composites; Xylose
• ISSN: 0920-5861; 1873-4308
• DOI: 10.1016/j.cattod.2016.06.042

[Display omitted] •Amino-functionalized SiO2-PSSA nanocomposites were prepared by sol-gel routes.•Amino-functionalization aimed at minimizing the polymer leaching.•These inorganic-organic nanohybrids were tested as acid catalysts in two reactions.•Extensive polymer leaching was observed when used in xylose to furfural reaction.•Leaching of polymer was much less intense in the biodiesel synthesis reaction. Silica-poly(styrene sulphonic acid) nanocomposites (SiO2-PSSA) were prepared using sol-gel methodologies. An amino functionalized organosilane (APTES) provides the anchoring sites for the retention of this acid polymer by the silica particles network. Aiming at optimizing the polymer loading and stability, different SiO2-PSSA nanocomposites were prepared by changing the type of solvent used in the synthesis, the aging protocol of the gel and the relative concentration of APTES. The effect of these modifications on the catalytic properties of the nanocomposites was explored in two different reactions driven by acid catalysts: xylose dehydration to furfural and esterification of oleic acid with methanol to yield biodiesel. Both reactions are of interest in the valorization of biomass and represent two illustrative cases to exploring the hydrothermal stability of the SiO2-PSSA nanocomposites under different conditions: aqueous phase at moderately high reaction temperatures (453K) and organic medium (methanol and oil) at low reaction temperature (333K), respectively. Polymer leaching was very intense in the case of furfural reaction because of the severe reaction conditions. On the contrary, for the case of the esterification of oleic acid, a reaction conducted under milder conditions, the deactivation by leaching is significantly prevented.