화학공학소재연구정보센터
Applied Catalysis B: Environmental, Vol.248, 31-43, 2019
Zirconium-lignosulfonate polyphenolic polymer for highly efficient hydrogen transfer of biomass-derived oxygenates under mild conditions
Both value-added utilization of low-rank renewable feedstocks to prepare catalytic materials and selective transformation of bioderived aldehydes are very attractive topics. Herein, lignosulfonate, a waste by-product from the paper industry, was simply assembled with ZrCl4 under non-toxic hydrothermal conditions for scalable preparation of Zr-containing polyphenolic biopolymer catalysts (Zr-LS). Systematic characterizations indicated that the strong coordination between Zr4+ and phenolic hydroxyl groups in lignosulfonate led to the formation of strong Lewis acid-base couple sites (Zr4+-O2-) and porous inorganic-organic framework structure (mesopores centered at 6.1 nm), while the inherent sulfonic groups in lignosulphonate could serve as Bronsted acidic sites. The cooperative role of these versatile acid-base sites in Zr-LS afforded excellent catalytic performance for Meerwein-Ponndorf-Verley (MPV) reaction of a broad range of bioderived platform chemicals under mild conditions (80 degrees C), especially of furfural (FF) to furfuryl alcohol (FA), in quantitative yields (96%) with high FA formation rate of 9600 mu mol g(-1)h(-1) and TOF of 4.37 h(-1). Kinetic studies revealed that the activation energy of the MPV reduction of FF was as low as 52.25 kJ/mol, accounting for the high reaction rate. Isotopic labelling experiments demonstrated direct hydrogen transfer from the alpha-C of 2-PrOH to the alpha-C of FF on acid-base sites was the rate-determining step. Moreover, Zr-LS showed good recyclability for at least seven reaction cycles.