Enhanced production of levulinic acid/ester from furfural residue via pretreatment and two-stage alcoholysis

• Published in: Biomass conversion and biorefinery 2023-02, Vol.13 (4), p.2933-2946
• Main Authors: Zhao, Sibo, Wang, Zihua, Chang, Chun, Li, Pan, Xu, Guizhuan, Pang, Shusheng
• Format: Article
• Language: English
• Subjects: Aluminum sulfate; Biotechnology; Conversion; Energy; Furfural; Hydrogen peroxide; Levulinic acid; Original Article; Pretreatment; Reaction kinetics; Renewable and Green Energy; Residues; Sulfuric acid
• ISSN: 2190-6815; 2190-6823
• DOI: 10.1007/s13399-021-01307-1

A two-stage alcoholysis was developed for improved conversion of furfural residue (FR) into levulinic acid (LA) and methyl levulinate (ML). Mixed acids including 0.01 M of H 2 SO 4 and Al 2 (SO 4 ) 3 and methanol/water (50/50 v/v%) were identified as the suitable catalyst and reaction medium. The optimum alcoholysis conditions were 198 °C and 1.5 h for the 1st stage and then 163 °C and 1.3 h for the 2nd stage, and the maximum total yield of LA and ML can reach 25.64%. The reaction kinetics and possible conversion pathways for ML and LA production were proposed. On the basis, HCOOH/H 2 O 2 pretreatment was screened for the pretreatment of FR, which increased the cellulose content of FR from 40.01 to 71.91%. The maximum total yield of LA and ML from pretreated FR was 44.96% under the optimum conditions of 195 °C and 1.9 h for the 1st stage and then 166 °C and 1.1 h for the 2nd stage, which was 16.09% higher than that of isothermal alcoholysis. The reusability tests showed that the Al 2 (SO 4 ) 3 was stable and can be reused at least 5 times. This study developed a new method for high-value utilization of FR and cleaner production of LA and ML.