Catalytic valorisation of biomass levulinic acid into gamma valerolactone using formic acid as a H2 donor: a critical review

This review sheds light on the catalytic valorisation of agroforestry biomass through levulinic acid and formic acid towards gamma-valerolactone and other higher-value chemicals. gamma-Valerolactone is produced by the hydrogenation of levulinic acid, which can be achieved through an internal hydrogen transfer reaction with formic acid in the presence of catalyst. By reviewing corresponding catalysts, the paper underlines the most efficient steps constituting an integrated sustainable process that eliminates the need for external H-2 sources while producing biofuels as an alternative energy source. Furthermore, the review emphasizes the role of catalysts in the hydrogenation of levulinic acid, with special focus on heterogeneous catalysts. The authors highlighted the dual role of different catalysts by comparing their activity, morphology, electronic structure, synergetic relation between support and doped species, as well as their deactivation and recyclability. Acknowledging the need for green and sustainable H-2 production, the review extends to cover the role of photo catalysis in dissociating H-2-donor solvents for reducing levulinic acid into gamma-valerolactone under mild temperatures. To wrap up, the critical discussion presented enables readers to hone their knowledge about different schools and emphasizes research gaps emerging from experimental work. The review concludes with a comprehensive table summarizing the recent catalysts reported between the years 2017-2021.

Automated summary

This review explores the catalytic valorisation of agroforestry biomass towards high-value chemicals, particularly gamma-valerolactone. It focuses on the role of catalysts, highlighting the efficiency of the hydrogenation of levulinic acid through an internal hydrogen transfer reaction with formic acid. The review also discusses heterogeneous catalysts and the use of photo catalysis for H-2 production. Overall, it provides readers with valuable knowledge and identifies research gaps in the field.