The SO3H-functionalized carbonaceous@montmorillonite efficient heterogeneous catalyst for synthesis of trimethylolpropane from long-chain fatty acid

As the increasing demand of bio-lubricants in industries, the new green synthetic method to polyolesters has attracted lots of attention. Herein, we report a novel efficient heterocatalyst contained sulfonic acid group, which was assembled through hydrothermal carbonization with the mixture carbon source of chitosan and furaldehyde, the hydroxyethylsulfonic acid aqueous solution was added as SO3H source. The obtained carbonaceous intercalated clay composites conserved regular layered and enlarged specific surface areas and pore volumes, which were proved by small-angle XRD, SEM and N-2 sorption isotherms. The FT-IR, XPS, C-13 CP/MAS NMR spectrum, Raman spectra and elemental analysis were employed to confirm the SO3H groups and its loading level. As an acidic heterogeneous catalyst for esterification between trimethylolpropane and oleic acid, synthesized SO3H-loaded carbonaceous intercalated montmorillonite composite exhibits high catalytic activity under the solvent-free conditions. The yield of the desired bio-lubricant is as high as 91% in 3 h. With little loss of catalytic activity after be reused five times, the SO3H-functionalized carbonaceous intercalated montmorillonite composite shows good reusability.