A selective oxidative depolymerization of larch lignin to ethyl vanillate by multifunctional catalysts combining alkaline ionic liquid and polyoxometalates with hydrogen peroxide

Kuiyuan Cao; Fang Yang; He Wan; Xixin Duan; Junyou Shi; Zhong Sun

doi:10.1016/j.ijbiomac.2025.139642

A selective oxidative depolymerization of larch lignin to ethyl vanillate by multifunctional catalysts combining alkaline ionic liquid and polyoxometalates with hydrogen peroxide

Int J Biol Macromol. 2025 Jan 8:139642. doi: 10.1016/j.ijbiomac.2025.139642. Online ahead of print.

Authors

Kuiyuan Cao¹, Fang Yang¹, He Wan¹, Xixin Duan², Junyou Shi¹, Zhong Sun³

Affiliations

¹ Key Laboratory of Wooden Materials Science and Engineering, Beihua University, 3999 East Binjiang Road, Fengman District, Jilin 132013, China.
² Key Laboratory of Wooden Materials Science and Engineering, Beihua University, 3999 East Binjiang Road, Fengman District, Jilin 132013, China. Electronic address: duanxixin@beihua.edu.cn.
³ School of Chemical Engineering, Northeast Electric Power University, 169 Changchun Road, Shipyard District, Jilin 132012, China.

PMID: 39793812
DOI: 10.1016/j.ijbiomac.2025.139642

Abstract

Ethyl vanillate (EV) is an important component of flavors and fragrances and has been widely used in the food, pharmaceutical, and cosmetic industries. The highly selective preparation of EV from lignin, the most abundant monophenolic compound in nature, is a great challenge in the field of lignin depolymerization. In this study, the multi-active catalysts from alkaline ionic liquid and polyoxometalates were constructed, which were characterized by acidity, alkaline and oxidizing ability. They can efficiently cleave the CC and CO bonds of larch lignin in an ethanol/water system at 160 °C for 10 h with H₂O₂ as an oxidizing agent. Vanillin and EV were main products with the phenolic yield of 10.14 wt% and the selectivity of EV was up to 83.63 %. The depolymerization of phenolic and non-phenolic lignin model compounds demonstrated that the cleavage of β-O-4 and C_α-C_β bonds contributed to the selective preparation of EV in the catalytic system. The catalyst can be recycled up to 4 times with excellent stability and recoverability. This study provides a new approach for the production of EV, which is promising in the high-valued utilization of larch waste.

Keywords: Ethyl vanillate; Larch; Selective depolymerization.