Selective transformation of carbohydrates to hydroxymethyl furfural with polyaniline-based catalysts

Abstract

The efficient production of 5-hydroxymethyl furfural (HMF) from carbohydrates is achieved in the presence of polyaniline-based solid catalysts. The composite polyaniline–graphite oxide (PANI–GO) is prepared from in situ polymerization of aniline in the solution of colloidal GO which was obtained from oxidation of graphite with Hummers’ method. Moreover, the SO 4 2 /PANI and SO 4 2− /PANI–GO materials were synthesized from the sulfation of PANI and PANI–GO by a 70 % sulfuric acid solution. All obtained samples are respectively characterized with XRD, TG, FTIR, SEM and TEM techniques to reveal the physical properties and structures of these materials. When these materials were used in the dehydration of d-fructose, it was found that the PANI–GO and SO 4 2− /PANI–GO as the catalyst exhibited prominent activities in which 80.7 and 72.4 % yields of HMF were obtained in N-methylpyrrolidone solvent at 160 °C for 4 h. In addition, the effects of reaction temperature, time, solvents and the recycling of PANI–GO material were also investigated. The material provides a promising method for the catalytic conversion of other biomass feedstocks. Metal-free and efficient conversion of different carbohydrates to 5-hydroxymethyl furfural (HMF) with a novel PANI–GO catalyst has been successfully performed.