Furfural and 5‐Hydroxymethylfurfural Production from Sugar Mixture Using Deep Eutectic Solvent/MIBK System

Abstract

Choline chloride (ChCl) / glycolic acid (GA) deep eutectic solvent (DES) media with high water content but without any additional catalyst are introduced in furfural and 5hydroxymethylfurfural (HMF) production. The effects of water content, reaction time, and reaction temperature are investigated with two feedstocks: a glucose/xylose mixture and birch sawdust. Based on the results, 10 equivalent quantities of water (32.9 wt.%) were revealed to be beneficial for conversions without rupturing the DES structure. The optimal reaction conditions were 160 °C and 10 minutes for the sugar mixture and 170 °C and 10 minutes for birch sawdust in a microwave reactor. High furfural yields were achieved, namely 62 % from the sugar mixture and 37.5 % from birch sawdust. HMF yields were low, but since the characterization of the solid residue of sawdust, after DES treatment, was revealed to contain only cellulose (49 %) and lignin (52 %), the treatment could be potentially utilized in a biorefinery concept where the main products are obtained from the cellulose fraction. Extraction of products into the organic phase (methyl isobutyl ketone, MIBK) during the reaction enabled the recycling of the DES phase, and yields remained high for three runs of recycling.

Recent Advances in the Catalytic Conversion of Biomass to Furfural in Deep Eutectic Solvents

“…Two methods are generally used to produce furfural in the DES system. In the “two-step method” in which the lignin carbohydrate complex is destroyed by pretreatment, the hemicellulose-derived sugar is selectively dissolved from the biomass, and then the acidified aqueous DES solution is used to produce furfural from the xylose-rich pretreatment solution ( Arora et al, 2021 ), and the “one-step method” in which the acidified DES is used to produce furfural by directly treating pentosan or biomass ( Lee et al, 2019 ; Rusanen et al, 2021 ). The reaction can be further enhanced to promote furfural synthesis if Brønsted acid or Lewis acid catalyst is added to the DES system to some extent ( Wang et al, 2018 ; Chen and Wan, 2019 ).…”

“…Annu et al investigated the effect of different water contents on the yield of furfural in a deep eutectic solvent system. In the MIBK/DES biphasic system, higher furfural yields of 62% and 37.5% ( Table 3 , entry 1–2) were obtained for the sugar mixture and birch sawdust, respectively, when 32.9 wt% water was added to the microwave reactor ( Rusanen et al, 2021 ). Water can promote furfural production, but too much water in the system can be harmful to getting enough furfural.…”

“…Water can promote furfural production, but too much water in the system can be harmful to getting enough furfural. When the amount of water injected exceeded 40 wt%, the yield of furfural decreased significantly ( Rusanen et al, 2021 ). Excess water breaks the hydrogen bond between HBD and HBA and also promotes the formation of humins, thus obtaining a low furfural yield ( Hammond et al, 2017 ; Gabriele et al, 2019 ).…”

Sulfonic acid functionalized dendrimer-grafted cellulose as a solid acid catalyst for the high-yield and green production of 5-hydroxymethylfurfural

“…1,2 Academic and commercial research has thus focused on the transformation of biomass to valuable products. 3,4 Among them, 5-hydroxymethylfurfural (5-HMF) is manufactured by acid-catalyzed carbohydrate dehydration, 5 and has been used successfully as a key biorening intermediate for the synthesis of highperformance liquid fuels and ne chemicals. 6,7 Other derivatives of 5-HMF, such as levulinic acid, 2,5-dimethylfuran, and 2,5-furandicarboxylic acid, are also considered to be valuable fuel additives.…”

Continuous flow Meerwein–Ponndorf–Verley reduction of HMF and furfural using basic zirconium carbonate

“…Studies range from new Lewis acid materials, cascade reactions and non-conventional systems. 15,[22][23][24][25][26][27] Other researchers have explored hydrous zirconia in continuous ow for hydride transfer reactions, although not focusing on biomass-derived compounds. 28,29 We have decided to explore a commercially available basic zirconium carbonate as catalyst under liquidphase continuous ow conditions.…”