The influence of the size of aromatic monomers on the structure and catalytic activity of polymer solid acids

High activity hyper-crosslinked polymer solid acids (HCPSAs) were prepared from different aromatic monomers, the structure of which was regulated by selecting the type and size of aromatic monomers. The results indicated that aromatic monomers affect not only the skeleton structure of HCPSAs, but also the loading of active groups significantly. The structural change of HCPSAs displayed a certain regularity as the size of the aromatic monomer increased, however, the catalytic activity of HCPSAs in oleic acid methylation and cellulose hydrolysis exhibited different trend. HCPSA derived from thiophene presented the highest oleic acid conversion, while HCPSA prepared from phenanthrene showed the highest reducing sugar yield. The highly active HCPSA for a specific reaction can be obtained by controlling aromatic monomers.