Metal- and halide-free catalysts supported on silica and their applications to CO2 cycloaddition reactions

Recent developments in state-of-the-art silica-modified catalysts for the fixation of CO2 in epoxides to form organic carbonates

“…Also, this enhanced the catalytic activity by facilitating the access of the reactants to the surface-active sites. 224…”

Cycloaddition of CO2 to epoxides by highly nucleophilic 4-aminopyridines: establishing a relationship between carbon basicity and catalytic performance by experimental and DFT investigations

“…In 2007, Shiels and Jones reported the DMAP-catalyzed synthesis of propylene carbonate from propylene oxide (PO) reaching high PO conversion at 120 °C and 34 bar CO2. 56 More recently, some single-component halogen-and metalfree homogeneous catalysts were reported to operate under slightly milder conditions (T: 100-120 °C, PCO2: 10-20 bar) based on Schiff bases, 57,58 tertiary amines, [59][60][61] ammonium salts 62 and N-heterocyclic compounds (triazoles, azolates, 2aminopyridines, DBU, adducts of imidazolium compounds). [63][64][65][66][67][68] Similarly, metal-and halogen-free heterogeneous catalyst were recently reported that operate efficiently in the 120-140 °C temperature range and at CO2 pressures ≥ 10 bar.…”

“…[63][64][65][66][67][68] Similarly, metal-and halogen-free heterogeneous catalyst were recently reported that operate efficiently in the 120-140 °C temperature range and at CO2 pressures ≥ 10 bar. 61,[69][70][71] Therefore, the cycloaddition of CO2 to epoxides by halide-free homogeneous and heterogeneous organocatalysts under atmospheric pressure remains underreported; Verpoort et al have very recently reported that nitrogen-rich triazole rings bearing carboxylic acid functionalities were competent halogen-free organocatalysts for atmospheric CO2 cycloaddition to several epoxides in the 75-100 °C temperature range. 63 However, as a potential drawback, the most active catalyst of this class was a derivative of highly toxic and environmentally hazardous mesitylene (GHS08, GHS09).…”

Homogeneous and Heterogeneous Ionic Liquid System: Promising “Ideal Catalysts” for the Fixation of CO2 into Cyclic Carbonates

“…[3] To reduce the emissions, CO 2 capture and storage (CCS) technology and CO 2 capture and utilization (CCU) technology were developed in recent years and considered as promising strategies. [4][5][6] Due to its large amount and non-toxic property, CO 2 can be utilized as feedstock of chemical processes. [7][8] Up to now, many kinds of chemicals such as methanol, [9] formic acid, [10] urea, [11] oxazolidinones [12] and organic carbonates [13] have been synthesized from CO 2 .…”