Catalytic Transfer Hydrogenation of Lignocellulosic Biomass Model Compounds Furfural and Vanillin with Ethanol by an Air‐stable Iron(II) Complex. Issue 3 (9th November 2022) - Ghosh, Rahul
Abstract: The chemical transformation of lignocellulosic biomass into various fine chemicals is the necessity for sustainable developments. A significant research interest has been devoted to develop catalysts for the reduction of cellulose and lignin model compounds furfural and vanillin, respectively. An iron(II) complex (1 ) was readily synthesized by facile coordination of NNO pincer ligand with FeCl2 .4H2 O. The air‐stable complex 1 was efficiently utilized for the catalytic transfer hydrogenation of furfural and vanillin using ecologically benign but challenging primary alcohol ethanol. Secondary alcohol isopropanol was also utilized. Various other biomass model compounds and structurally related aldehydes were also effectively reduced. Kinetic studies suggested first order kinetics in catalyst and zeroth order in substrate. Based on the experimental evidences and published reports, a catalytic cycle is proposed which proceed via iron(II)‐dialkoxides and alkoxide‐hydride intermediates. Finally, CHEM21 green metrics toolkit was utilized to evaluate the sustainable and green credentials of the catalytic protocols. Abstract : Readily available, air‐stable and sustainable iron complex was efficiently used for the transfer hydrogenation of biomass model compounds vanillin and furfural selectively to vanillyl alcohol and furfuryl alcohol with wide practical applications. Optimized transfer hydrogenation protocols were evaluated by CHEM21 green metrics toolkit as an extension of the 12 principles of green chemistry.