Evaluation of potential of sweet sorghum bagasse for production of value-added chemicals: 5-Hydroxymethyl furfural and its derivatives

Abstract

The potential of sweet sorghum bagasse has been evaluated for production of value-added chemicals like 5-hydroxymethyl furfural, 2,5-dimethyl furan, 2,5-furandicarboxylic acid and its ester derivatives. 5-Hydroxymethyl furfural (HMF) has been synthesized from D-glucose and D-fructose separately and D-fructose is found to give higher yields. A catalytic strategy has been developed for the production of 2,5-dimethylfuran from HMF by choosing two different pathways for its production. The pathway involving oxidation with PCC/CH₂Cl₂ followed by Wolf-Kishner reduction is found to be better than the other pathway which involve reduction of HMF with subsequent chlorination with SOCl₂ and reduction with LiAlH₄. To estimate the production potential of HMF from sweet sorghum bagasse, it is pretreated with different concentrations of alkali i.e. 2% H₂O_­2, 1% NaOH, 2% H₂O₂+1% NaOH each with pH 11.5 and 13 for 24, 48 and 72 h followed by acid saccharification with 0.8M H₂SO₄ for 50 min at 1.05 kg cm^-2 steam pressure. The maximum production potential of HMF from glucose is found 0.119g HMF/g bagasse. These chemical transformations provide a new paradigm for utilization of sweet sorghum bagasse as a raw material for biofuels and chemicals.