Preparation of 5-HMF by hydrothermal treatment of palm kernel shell residues

Abstract

Hydrothermal treatment of biomass is one of the most promising technologies for converting biomass into a higher value-added form. It is well recognized that palm oil production is one of the major industries in Thailand, which generates many palm kernel shell residues. This work focuses on utilizing hydrothermal treatment of cellulose in palm kernel shell residues for 5-hydroxymethyl-furfural (5-HMF) production. Because the palm kernel shell residues contain cellulose approximately 60 wt%, it would possibly provide a high yield of sugar and furfural products. Palm kernel shells residues were treated by alkali solutions before adding into a batch-type tubular reactor. A series of systematic experiments were performed in a reaction temperature range of 200 to 300℃, heating rate ranging from 5 to 10℃/min, concentration of palm kernel shell residues (feedstock) at 10 and 20 wt%, effect of lignin content. It was found that the 5-HMF yield was obviously dependent on the reaction temperature, heating rate, concentration of feedstock and lignin content. Furthermore, the effect of concentration of 2-butanol, phosphoric acid (H3PO4) and dimethyl sulphoxide (DMSO) were also investigated. Experimental results have shown that 2-butanol and DMSO were good selective solvents for the production of 5-HMF in the hydrothermal treatment process. It could be firmly believed that the liquid product obtained from the hydrothermal treatment consisted of 1,3-dihydroxyacetone dimer, formic acid, acetaldehyde, 5-hydroxymethylfurfural (5-HMF), acetic acid and furfural