High-Yield 5-Hydroxymethylfurfural Synthesis from Crude Sugar Beet Juice in a Biphasic Microreactor

5-Hydroxymethylfurfural (HMF) is an important biobased platform chemical obtainable in high selectivity by the hydrolysis of fructose (FRC). However, FRC is expensive, making the production of HMF at a competitive market price highly challenging. Here, it is shown that sugar beet thick juice, a crude, sucrose-rich intermediate in sugar refining, is an excellent feedstock for HMF synthesis. Unprecedented high selectivities and yields of '90 % for HMF were achieved in a biphasic reactor setup at 150 °C using salted diluted thick juice with H2SO4 as catalyst and 2-methyltetrahydrofuran as a bioderived extraction solvent. The conversion of glucose, obtained by sucrose inversion, could be limited to '10 mol %, allowing its recovery for further use. Interestingly, purified sucrose led to significantly lower HMF selectivity and yields, showing advantages from both an economic and chemical selectivity perspective. This opens new avenues for more cost-effective HMF production

5-Hydroxy-2-Methylfurfural from Sugar Beet Thick Juice:Kinetic and Modeling Studies

5-Hydroxy-2-methylfurfural (HMF) has a high derivatization potential and is considered the sleeping giant of biobased platform chemicals. It is accessible by the acid hydrolysis of various carbohydrate-containing feeds, preferably those high in fructose content. We here report a detailed study on the use of thick juice, an intermediate sucrose (SUC)-rich stream in a sugar factory, and pure SUC for the synthesis of HMF in a batch reactor setup [in the presence of water and sulfuric acid (0.01 M) and at 180 °C]. Distinct differences in reactivity were found for both feeds, related to the presence of impurities (i.e., organic acids and salts) in the thick juice. To better understand the effect of the thick juice impurities, detailed model studies were performed involving the use of a model solution of SUC spiked with one of the thick juice impurities (organic acids such as maleic acid and a range of salts with potassium, sodium, calcium, and magnesium as the cations and carbonates, chlorides, and sulfates as the anions). The data were successfully modeled using a kinetic model for the main reactions in the network. The developed model revealed that sulfate anions have a major effect on the HMF yield and the batch time required to reach its optimum and are the likely cause of the differences in reactivity between pure SUC and thick juice

Experimental and Kinetic Modeling Studies on the Conversion of Sucrose to Levulinic Acid and 5-Hydroxymethylfurfural Using Sulfuric Acid in Water

We here report experimental and kinetic modeling studies on the conversion of sucrose to levulinic acid (LA) and 5-hydroxymethylfurfural (HMF) in water using sulfuric acid as the catalyst. Both compounds are versatile building blocks for the synthesis of various biobased (bulk) chemicals. A total of 24 experiments were performed in a temperature window of 80–180 °C, a sulfuric acid concentration between 0.005 and 0.5 M, and an initial sucrose concentration between 0.05 and 0.5 M. Glucose, fructose, and HMF were detected as the intermediate products. The maximum LA yield was 61 mol %, obtained at 160 °C, an initial sucrose concentration of 0.05 M, and an acid concentration of 0.2 M. The maximum HMF yield (22 mol %) was found for an acid concentration of 0.05 M, an initial sucrose concentration of 0.05 M, and a temperature of 140 °C. The experimental data were modeled using a number of possible reaction networks. The best model was obtained when using a first order approach in substrates (except for the reversion of glucose) and agreement between experiment and model was satisfactorily. The implication of the model regarding batch optimization is also discussed

High-Yield 5-Hydroxymethylfurfural Synthesis from Crude Sugar Beet Juice in a Biphasic Microreactor

5-Hydroxymethylfurfural (HMF) is an important biobased platform chemical obtainable in high selectivity by the hydrolysis of fructose (FRC). However, FRC is expensive, making the production of HMF at a competitive market price highly challenging. Here, it is shown that sugar beet thick juice, a crude, sucrose-rich intermediate in sugar refining, is an excellent feedstock for HMF synthesis. Unprecedented high selectivities and yields of '90 % for HMF were achieved in a biphasic reactor setup at 150 °C using salted diluted thick juice with H2SO4 as catalyst and 2-methyltetrahydrofuran as a bioderived extraction solvent. The conversion of glucose, obtained by sucrose inversion, could be limited to '10 mol %, allowing its recovery for further use. Interestingly, purified sucrose led to significantly lower HMF selectivity and yields, showing advantages from both an economic and chemical selectivity perspective. This opens new avenues for more cost-effective HMF production

Experimental and Kinetic Modeling Studies on the Sulfuric Acid Catalyzed Conversion of d‑Fructose to 5‑Hydroxymethylfurfural and Levulinic Acid in Water

Levulinic acid (LA) and 5-hydroxymethylfurfural (HMF) have been identified as promising biomass-derived platform chemicals. A kinetic study on the conversion of d-fructose to HMF and LA in water using sulfuric acid as the catalyst has been performed in batch setups. The experiments were carried out in a temperature window of 140–180 °C, using sulfuric acid as the catalyst (0.005–1 M) and an initial d-fructose concentration between 0.1 and 1 M. A kinetic model for the conversion of d-fructose to HMF and the subsequent reaction of HMF to LA was developed including the kinetics for the formation of solid byproducts (humins) using a power-law approach. According to the model, the maximum attainable HMF yield in the experimental window is 56 mol % (<i>C</i>_fruc = 0.1 M; <i>C</i>_acid = 0.005 M; 166 °C), which is close to the highest experimental value within the range (53 mol %) and considerably higher than that reported for d-glucose. The highest modeled LA yield was 70 mol % (<i>C</i>_fruc = 0.1 M; <i>C</i>_acid = 1 M; 140 °C), close to the experimental value of 74 mol %. This LA yield is considerably higher than that found for d-glucose within the range of experimental conditions. The model was used to determine the optimum reactor configuration for highest HMF and LA yields, and it is shown that highest HMF yields are attainable in a PFR reactor, whereas a large extent of backmixing is favorable when aiming for a high LA yield

High-Yield 5-Hydroxymethylfurfural Synthesis from Crude Sugar Beet Juice in a Biphasic Microreactor

5-Hydroxymethylfurfural (HMF) is an important biobased platform chemical obtainable in high selectivity by the hydrolysis of fructose (FRC). However, FRC is expensive, making the production of HMF at a competitive market price highly challenging. Here, it is shown that sugar beet thick juice, a crude, sucrose-rich intermediate in sugar refining, is an excellent feedstock for HMF synthesis. Unprecedented high selectivities and yields of '90 % for HMF were achieved in a biphasic reactor setup at 150 °C using salted diluted thick juice with H2SO4 as catalyst and 2-methyltetrahydrofuran as a bioderived extraction solvent. The conversion of glucose, obtained by sucrose inversion, could be limited to '10 mol %, allowing its recovery for further use. Interestingly, purified sucrose led to significantly lower HMF selectivity and yields, showing advantages from both an economic and chemical selectivity perspective. This opens new avenues for more cost-effective HMF production