Conversion of Sugar Cane Molasses to 5-Hydroxymethylfurfural Using Molasses and Bagasse-Derived Catalysts

Abstract

5-hydroxymethylfurfural (HMF) is a suitable platform chemical for the production of useful chemicals and fuels. This study examined the hydrolysis of mixtures of sucrose, glucose and fructose (synthetic sugar cane molasses) and industrial molasses using sulfonated carbon-based heterogeneous catalysts derived from sugar cane bagasse (B-SO3H) and sugar cane molasses (M-SO3H). Microwave heating at 150 °C for 4 h produced 39 mol % HMF yield with B-SO3H on the synthetic sugar solution. The addition of a molasses pretreatment step, as well as, increasing the microwave power was necessary to achieve similar HMF yields with the industrial molasses sample. The hydrolysis of molasses pretreated with formic acid or HCl resulted in a slightly higher HMF yield than the hydrolysis of molasses pretreated with H2SO4. The buffering capacity of the formic acid pretreated molasses was lowered through dilution with water; and subsequently HMF yield was increased to 64.3 mol % (170 °C, 3 h).

Eco‐Friendly Production of 5‐Hydroxymethylfurfural from Sucrose Using Commercially Available Dihydric Phosphate as a Catalyst

“…In addition, comparing the yields of HMF, glucose, and fructose with the conversion of sucrose, the HMF was formed mainly through the dehydration of fructose unit in sucrose by an autocatalysis process in the subcritical water ,. It should be noted that, at this condition, the selectivity of HMF is 90.3%, demonstrating the co‐existence of the intermediates or byproducts which was not detected by HPLC ,…”

“…Further analysis of the distribution of products show that the yields of glucose and fructose give the different trend as the yield of HMF; the more catalyst added, the less glucose and fructose retained, indicating the catalyst benefitted their conversion, and leading to 8.7% of glucose and 3.9% of fructose retained at 60% of catalyst dosage. It should be noted that the yield of glucose was higher than fructose probably due to the quicker conversion of fructose into HMF than glucose ,,. Interestingly, the glucose can be converted into fructose through the isomerization process, which is considered as a significant contribution for fructose yield .…”

“…[9f,16b] It should be noted that, at this condition, the selectivity of HMF is 90.3%, demonstrating 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 the co-existence of the intermediates or byproducts which was not detected by HPLC. [6,18] When H 3 PO 4 was added into the reaction system, complete conversion of sucrose was achieved (Table 1, entry 2). The lower yields of HMF (26.4%) and fructose (13.8%) implied the formed HMF from the dehydration of fructose unit was instable in this H 3 PO 4 -containing reaction system, resulting in lower HMF selectivity (49.9%).…”

“…In comparison to fructose, sucrose, containing one fructose moiety and one glucose moiety in the molecular structure, is an accessible and available renewable candidate for producing HMF because it has been produced in large scale commercially through the squeezing of fresh sugar cane or beet, followed by the concentration and crystallization processes . Currently, ∼250 million tonnes of sugar can be produced yearly from >1.8 billion tonnes of sugar cane worldwide . It has been evidenced that the fructose moiety in sucrose can be converted into HMF via hydrolysis and dehydration steps in the presence of proton acid catalysts (mineral acids, organic acids, solid acids, etc.…”

“…[5] Currently, ∼ 250 million tonnes of sugar can be produced yearly from > 1.8 billion tonnes of sugar cane worldwide. [6] It has been evidenced that the fructose moiety in sucrose can be converted into HMF via hydrolysis and dehydration steps in the presence of proton acid catalysts (mineral acids, organic acids, solid acids, etc. ), [7] and the perspective to economical conversion of sucrose into HMF has motivated tremendous amount of researches recently.…”