Rapid Transformation of Furfural to Biofuel Additive Ethyl Levulinate with In Situ Suppression of Humins Promoted by an Acidic-Oxygen Environment

Abstract

Sustainable production of biofuel additive ethyl levulinate (EL) from biomass-derived furfural (FF) is an interesting way owing to its application in improving the diesel combustion process without the expense of octane number. In this study, a stable mesoporous SO 3 H@Ni−Al catalyst prepared via facile a hydrothermal-functionalization process was characterized and applied for ultrasound-assisted transformation of FF into EL using ethanol as a hydrogen donor. Interestingly, the formation of humins in the mixture solution and on the catalyst surface was effectively suppressed after introduction of an oxygen environment, resulting from an oxidative degradation reaction. The optimization process was carried out under catalyst acidity, ultrasonic power generation, and statistical design. As desired, a high yield of EL (∼97%, E a = 25.95 kJ/mol) without humins' formation was well achieved in a shorter reaction time (95 min) and at a low reaction temperature (112 °C), compared with a previous conventional reaction. Moreover, the introduction of oxygen strongly promoted the catalyst reusability with a slight reduction in its catalytic behavior, while selectivity/distribution in the liquid product had slight differentiation.

Highly Efficient Transfer Hydrogenation of Biomass-Derived Furfural to Furfuryl Alcohol over Mesoporous Zr-Containing Hybrids with 5-Sulfosalicylic Acid as a Ligand

“…The content of Zr in the filtrate of each run was detected to be below the detected limit (0.1 mg/L) by ICP-OES, indicating that the leaching of Zr was negligible due to the strong interaction of 5-sulfosalicylic acid and Zr 4+ [ 50 , 51 ]. Moreover, the reaction was performed under a relatively low temperature (110 °C) so that the formation of humins could be greatly suppressed [ 52 , 53 ], avoiding deactivation of the catalyst accordingly. Similar results were also obtained when the reaction time was extended to 2 h ( Table S3 ).…”

Zr Oxo Cluster for Cascade Conversion of Furfural to Alkyl Levulinates

“…Notably, as the density of Brönsted acid continued to increase up to 4.8 mmol/g, the DBMF disappeared and only BL was detected with a yield of 91 %, which implied that the acetalization reaction might be reversible under the reaction conditions (Scheme 1). [19,33] Furthermore, the alcoholysis reaction can be carried out on a large scale (FAL, 2.0 g) and BL was isolated by distillation in 86.5 % isolated yield (3.1 g) with high purity after the reaction. The purity of BL was confirmed by 1 H NMR and 13 C NMR (Figure S4).…”

Hybrid Nanocomposite Comprising Mg–Al Hydrotalcite Nanocrystals on ZSM-5 Zeolite for Production of Renewable Fuel Additives from Furfural

“…Additionally, ethanol can be produced from renewable resources like biomass, which makes the route green and sustainable as well . Catalytic transfer hydrogenation of FUR and subsequent etherification/esterification in a cascaded manner are reported earlier. − Recent reports for the direct conversion of FUR to EL are tabulated in Table S1 (please refer to the Supporting Information). The main drawbacks associated with most of the existing catalytic systems are either the use of precious metal or lower EL yields or very high metal contents (up to 40 wt %) or requisite of microwave assistance, which makes them unsuitable to be used on a larger scale.…”