Dimethyl carbonate solvent assisted efficient conversion of lignocellulosic biomass to 5- hydroxymethylfurfural and furfural

Abstract

An efficient, economic, and one-pot process has been developed for the direct conversion of untreated biomass feedstock such as corn-cob, sugarcane bagasse, rice-straw, and corn-straw into 5-HMF and furfural (FF) synthesis in dimethyl carbonate (DMC) solvent conditions under a pressurized hydrothermal steel vial system. The use of DMC as a green solvent under acidic medium was explored first time for the transformation of complex lignocellulosic biomass into furanic compounds. Moreover, the DMC solvent under acidic environment partially produced CO2 that facilitates the depolymerization of recalcitrant biomass substrate and subsequently participates in conversion under the set conditions. Notably, the influence of various parameters such as temperature, time, solvents, and the synergistic functions of AlCl3 and HCl was examined to optimize the reaction conditions. After optimization, the maximum yield of 5-HMF and furfural from various biomass feedstock was recorded as 35–60% and 61–98% respectively within 6 h at 180 °C. Furthermore, we have described the relative compositions of biopolymers (cellulose, hemicellulose, and lignin), moisture/and ash content in each biomass substrate. The SEM analysis provided information about particle size and shape via calculating aspect ratio of mechanical grinded lignocellulosic biomass. Subsequently, the quantification of products was scrutinized through UPLC and further reconfirmed via NMR and ESI-MS analysis techniques.