Exploring the Immobilization Strategies of Lewis Bases on Lignocellulosic Bamboo Shavings and their Applications in Cycloaddition of CO2 and CO2 Derivatives

For the first time, the immobilization of Lewis base molecular catalysts is demonstrated on lignocellulosic bamboo shavings for synthetic applications, focusing on the valorization of CO2 and its derivatives. Two types of catalysts are immobilized on bamboo shavings: covalent functionalization using isocyanate chemistry is employed to prepare Bamboo supported Hexaethylenedicarbamate ethyl methyl imidazolium iodide [Bamboo@ HMEMIM][I], while a silane-based approach is applied to obtain Bamboo supported 1,5,7-Triazabicyclo[4.4.0]dec-5-ene [Bamboo@TBD]. Both materials are fully characterized through elemental analysis, FT-IR, TGA, and Scanning Electron Microscopy (SEM). The first catalyst, [Bamboo@HMEMIM][I], promoted the cycloaddition of CO2 with epoxide, achieving 100% conversion and complete selectivity toward cyclic carbonates under optimized conditions (2.8 mol% catalyst, 10 bar CO2, at 70 °C for 16 h). This catalyst also demonstrates good recyclability, showing a decrease in activity only after four consecutive cycles (74% yield in the fourth cycle, 61% in the fifth). The reaction scope demonstrates its broad applicability for other epoxides (Y = 86−100%). The second catalyst is applied to the synthesis of glycerol carbonate through cycloaddition between dimethyl carbonate (DMC) and glycerol. Optimized conditions (5 mol% catalyst, 10:1 DMC:glycerol ratio, at 100 °C for 16 h) achieves 100% conversion and 69% selectivity for glycerol carbonate. In this case the degradation of catalysts by Phanerochaete chrysosporium is investigated.