Facile In Situ 5-EMF Synthesis and Extraction Processes from Catalytic Conversion of Sugar under Sustainable Long-Life Cycle

Abstract

The catalytic behavior for 5-ethoxymethylfurfural (5-EMF) formation was systematically studied via facile conversion of sucrose under a sustainable ultrasonic-biphasic system using an active ZnO nanofiber-deposited-SO 3 H-carbon catalyst (Zn-S-C). Interestingly, 5-EMF with a high yield could be easily obtained and separated from ethanol/tetrahydrofuran (THF) via green synthesis-extraction procedures in the presence of NaCl. Meanwhile, an actual 5-EMF yield of 93.5 ± 0.8% was successfully achieved at 98 °C for 47 min using a THF amount (0.25 mol) and catalyst adding amount (77.8 wt %) over the combination of 2 k factorial and Box−Behnken designs. The product selectivity and yield from sucrose conversion were systematically controlled by adjusting type/amount of catalyst, co-solvents or inorganic salts, and ultrasonic system. The activation energy (38.17 kJ/mol) obtained from ultrasound-assisted conversion of sucrose into 5-EMF was lower than that from the conventional system. Strikingly, a nonsignificant decrease in the turnover rate (TOR, min −1 ) for conversion of sucrose into 5-EMF appeared when the catalyst was reused up to 100 cycles, indicating long-life cycle stability of the as-prepared catalyst.

Catalytic Upgrading of Lignocellulosic Biomass Sugars Toward Biofuel 5-Ethoxymethylfurfural

“…Meanwhile, the lengthy chemical reaction process increased more by-products or humins (Zheng et al, 2021). Therefore, many studies were devoted to developing more efficient catalytic systems, which can obtain more satisfactory EMF yields from glucose or glucose-based carbohydrates (Guo et al, 2017;Guo et al, 2018;Karnjanakom et al, 2020;He et al, 2022). Some catalysts and reaction conditions for obtaining EMF from LCB-derived sugars were summarized in Table 1.…”

Catalytic Synthesis of the Biofuel 5-Ethoxymethylfurfural (EMF) from Biomass Sugars

“…With a "one-pot" method, direct assembly of EMF from disaccharides, polysaccharides, and biomass sugars shows obvious advantages in the economy and less energy intensity. is method can reduce the cost and steps of intermediate separation and purification [27][28][29]. But, it always has a relatively lower yield of EMF from these complex carbohydrates, compared with fructose, HMF, 5chloromethylfurfural (CMF), and 5-bromomethylfurfural (BMF) [29][30][31][32][33].…”

“…Generally, the yield of EMF is higher when fructose is used as raw material. Karnjanakom et al [27] used Zn-S-C to transform fructose into EMF (95.5% yield) in an ethanol solvent with tetrahydrofuran (THF) as a cosolvent under the optimal conditions (98 °C, 47 min). However, glucose as a substrate always leads to a low yield of EMF (10%-40%) [44,[47][48][49] due to the effect of the speed limit of glucose being isomerized into fructose.…”

“…However, due to a large number of byproducts from homogeneous acid catalysts, the corrosion of the equipment and the high requirements for reaction conditions have restricted their use in industry. erefore, green, economical, and recyclable heterogeneous catalytic systems have great potential in this field [27,55,[65][66][67][68].…”

“…Furthermore, Brønsted and Lewis acids can also be grafted into carbon-based materials. An amazing EMF yield was observed by utilizing a Zn-S-C catalyst from glucose-based carbohydrates, such as cellobiose (74.6%) and glucose (80.9%) [27]. Zn-S-C was formed by coloading ZnO and 2hydroxyethylsulfonic acid onto carbon-based material.…”