Bifunctional heterogeneous catalysts from biomass and waste polysaccharides for the conversion of CO₂ into cyclic carbonates

Abstract

A four-step methodology for the valorization of polysaccharide-based materials into bifunctional heterogenous catalysts, active in the conversion of CO2 and epoxides into cyclic carbonates, is presented. The synthesis protocol consists...

Poly(ionic liquid)s with unique adsorption-swelling ability toward epoxides for efficient atmospheric CO2 conversion under cocatalyst-/metal-/solvent-free conditions

“…Characterizations 1 H and 13 C NMR spectra were recorded using an AVANCE III HD 400 spectrometer (Bruker Daltonics Inc., USA) at the fre-quencies of 400 and 100 MHz, respectively. Solid-state CP/MAS 13 C NMR spectra were recorded using an AVANCE III HD 400 spectrometer (Bruker Daltonics Inc., USA) equipped with a 4 mm ZrO 2 rotor at a frequency of 100 MHz, a spinning rate of 5.0 kHz, and a recycling delay of 6.5 s. Fourier transform infrared (FT-IR) spectra were obtained on a Nicolet iS50 FT-IR spectrometer (Thermo Fisher Scientific, USA) using KBr pellets in the range of 4000-400 cm −1 . For in situ FT-IR measurement, the sample was filled into a variable-temperature IR cell, vacuumed, and heated to 80 °C.…”

“…Fig. 3a showed the solid-state CP/MAS 13 C NMR spectrum of P-[VC6Im]Br-C8-5% and 13 C NMR spectra of corresponding IL monomer [VC6Im]Br and crosslinker C8. In the spectrum of P-[VC6Im]Br-C8-5%, the peaks at around 129 and 109 ppm belonging to the carbons of vinyl groups in [VC6Im] Br and C8 were not observed, while new peaks assigned to the carbons of newly formed polymer chains were observed at around 53 and 39 ppm, indicating the complete polymerization of [VC6Im]Br and C8.…”

“…The ring-opening of epoxides usually involves the activation of Lewis acid centers (e.g., metallic centers, H-bond donors) and the nucleophilic attack of Lewis base centers (e.g., halide anions). 4,13 Ionic liquids (ILs) possess both acid centers (e.g., C-2H proton on imidazolium (Im) ring) and nucleophilic anions, enabling active CO 2 cycloaddition under cocatalyst-/ metal-free conditions. 14,15 Moreover, ILs feature flexible designability, which allows for precise design and regulate the nature of Lewis acid and base centers (i.e., strength, content, and spatial location) at the molecular level, thereby enhancing their catalytic activities.…”

“…, halide anions). 4,13 Ionic liquids (ILs) possess both acid centers ( e.g. , C-2H proton on imidazolium (Im) ring) and nucleophilic anions, enabling active CO 2 cycloaddition under cocatalyst-/metal-free conditions.…”

Synthetic, spectral, structural and catalytic activities of 3-D metal format/acetate framework materials for CO2 conversion

“…4 Cyclic carbonates are a kind of chemical intermediate in the production of plastics, organic solvents, etc. 5 Homogeneous and heterogeneous catalysts were developed for the cycloaddition of CO 2 and epoxides. Thus, many homogeneous catalysts, such as quaternary ammonium and phosphonium salts, 6 ionic liquids, 7 alkalimetal salts, 8 Schiff bases, 9 and metal-centered salen complex, 10 have been used to promote transformation.…”