Production of ethyl levulinate fuel bioadditive from 5-hydroxymethylfurfural over sulfonic acid functionalized biochar catalysts

• Published in: Fuel (Guildford) Vol. 303; p. 121227
• Main Authors: Peixoto, Andreia F., Ramos, Ruben, Moreira, Manuela M., Soares, O. Salomé G.P., Ribeiro, Lucilia S., Pereira, Manuel F.R., Delerue-Matos, Cristina, Freire, Cristina
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01.11.2021; Elsevier BV
• Subjects: 5-Hydroxymethylfurfural; Additives; Alkyl levulinates; Biochar; Biorefineries; Catalysts; Catalytic activity; Charcoal; Exploitation; Fuel additives; Heterogeneous catalysis; Hydrothermal treatment; Hydroxymethylfurfural; Lignocellulose; Reaction time; Sulfonated carbon-based catalysts; Sulfonation; Sulfonic acid; Vineyards; Heterogeneous catalysis; Biochar; 5-Hydroxymethylfurfural; Alkyl levulinates; Sulfonated carbon-based catalysts
• ISSN: 0016-2361; 1873-7153
• DOI: 10.1016/j.fuel.2021.121227

[Display omitted] •High active and selective aryl-SO3H functionalized biochar-based catalyst.•Superior catalytic activity for the production of ethyl levulinate as fuel additive.•Outstanding EL yields (over 84%) at 130 °C after 6 h over the BioC-S3 catalyst.•Competitive production of alkyl levulinates from lignocellulose-derived HMF. In this work, a series of novel -SO3H functionalized biochar materials were prepared and investigated for the first time as catalysts for the production of fuel additive ethyl levulinate (EL) from biomass-derived 5-hydroxymethylfurfural (HMF). The employed biochar was directly produced from vineyard pruning wastes by a simple hydrothermal treatment using water in subcritical conditions followed by 3 different one-step sulfonation processes. The effects of sulfonating agent, reaction temperature, reaction time and alcohol solvent were examined. Full HMF conversion together with outstanding EL yields (over 84%) were achieved at 130 °C and after 6 h over the biochar functionalized with the organosilane 2-(4-chlorosulphonylphenyl)ethyltrimetoxysilane (BioC-S3). Catalyst characterization suggested that the high acid strength (0.983 mmol H+·g−1) derived from the anchoring of arylsulfonic groups were responsible for the promotion of acid-driven etherification and ethanolysis steps. The BioC-S3 catalyst can be recycled without a significant loss of catalytic activity, indicating the stability of – SO3H organosilane group structure in the porous biochar. The obtained results offer a competitive alternative for the production of fuel additives, such as alkyl levulinates, using low-cost and easy-to-prepare biochar-based catalysts, all from lignocellulose resources, as an example to support a future exploitation of a potential biorefinery.