Search Results (3)

The total amount of cellulose from paper, wood, food, and other human activity waste produced in the EU is in the order of 900 million tons per year. This resource represents a sizable opportunity to produce renewable chemicals and energy. This paper reports, unprecedently in the literature, the usage of four different urban wastes such as cigarette butts, sanitary pant diapers, newspapers, and soybean peels as cellulose fonts to produce valuable industrial intermediates such as levulinic acid (LA), 5-acetoxymethyl-2-furaldehyde (AMF), 5-(hydroxymethyl)furfural (HMF), and furfural. The process is accomplished by the hydrothermal treatment of cellulosic waste using both Brønsted and Lewis acid catalysts such as CH₃COOH (2.5–5.7 M), H₃PO₄ (15%), and Sc(OTf)₃ (20% w:w), thus obtaining HMF (22%), AMF (38%), LA (25–46%), and furfural (22%) with good selectivity and under relatively mild conditions (T = 200 °C, time = 2 h). These final products can be employed in several chemical sectors, for example, as solvents, fuels, and for new materials as a monomer precursor. The characterization of matrices was accomplished by FTIR and LCSM analyses, demonstrating the influence of morphology on reactivity. The low e-factor values and the easy scale up render this protocol suitable for industrial applications. Full article

An alternative to 5-hydroxymethyl-2-furfural (HMF), which is a promising furan derivative that can be used as a starting material for the preparation of non-petroleum-derived polymeric materials from sugars, is 5-acetoxymethyl-2-furfural (AMF). The less-hydrophilic acetyl group of AMF has advantages over the hydroxy group of HMF in terms of thermal stability and isolation. In previous studies, fructose has been used as a starting material along with lipases for the enzymatic synthesis of AMF. In this study, we designed a hybrid synthesis system that includes the isomerization and esterification of glucose into AMF. For the step-by-step conversion of glucose to 1,6-diacetylfructose (DAF), glucose-isomerase and immobilized lipase (Novozym 435) were used as enzymes. Furthermore, for the synthesis of AMF, the direct dehydration of DAF was performed using a cation exchange resin (Amberlyst 15), combined with several industrial solvents, such as dimethylsulfoxide (DMSO), acetonitrile (AN) and dimethylformamide (DMF) for the synthesis of AMF. In order to improve the final yield of AMF, we determined the best solvent conditions. While the AMF yield after the direct dehydration of DAF in a single solvent was maximum 24%, an AMF and HMF yield in the mixed solvent such as dioxane and DMS (9:1) was achieved each 65% and 15%. According to these results, we found that the addition of dioxane in aprotic polar solvents could affect the dehydration reaction and dramatically improve the formation of AMF and HMF. Full article

5-Acetoxymethyl-2-furfural (AMF) was prepared from D-fructose via 1,6-diacetylfructose (DAF) through a simple two-step reaction pathway. Immobilized enzyme (Novozym 435) was found to be the best enzymatic catalyst for the trans-esterification step (yielding 94.6% DAF). In the dehydration step, while soluble H₂SO₄ was found to be the best acidic catalyst (yielding 86.6% AMF), we opted to utilize heterogeneous cation exchange resin (Amberlyst 15) together with recyclable industrial solvents (1,4-dioxane) for a more sustainable AMF synthesis procedure. Although the total yield of AMF was a little lower, both the enzyme and the solid acid catalyst could be recycled for five cycles without a significant loss of activity, which has a major contribution to the cost-efficient aspect of the entire process. Full article