Sulfonated Porous Polymeric Nanofibers as an Efficient Solid Acid Catalyst for the Production of 5-Hydroxymethylfurfural from Biomass

Sustainable supply of energy is one of the biggest challenges today. The conversion of energy from any abundant and renewable resources would be an ideal solution for this ever increasing demand of sustainable energy. Biomass provides a potential energy alternative through the platform chemical 5-hydroxymethylfurfural (HMF), which is considered as a sustainable source for liquid fuels and commodity chemicals. Herein, we report the synthesis of a nanoporous polytriphenylamine (PPTPA-1) having high surface area (1437m(2)g(-1)) by a simple one-step oxidative polymerization pathway. Upon sulfonation of PPTPA-1, the sulfonated polymer SPPTPA-1 showed very high surface acidity and it has been successfully employed as a solid acid catalyst for direct conversion of sugar to HMF. Both PPTPA-1 and SPPTPA-1 materials have distinct nanofiber morphologies and they are characterized thoroughly by using powder XRD, FTIR spectroscopy, C-13 solid state magic-angle-spinning NMR spectrometry, field-emission scanning electron microscopy, high-resolution transmission electron microscopy, and N-2 sorption techniques. We have optimized the HMF yields by using different carbohydrate sources and estimated the recycling efficiency of the catalyst.