Highly Efficient Solvent-free Conversion of CO₂ into Cyclic Carbonates by Acrylamide–KI

Abstract

The cycloaddition of CO2 with epoxide has been a promising way to fix CO2. Developing efficient, low-cost catalysts for this reaction is highly desired. In this paper, we report a novel cocatalyst system that consists of acrylamide and KI for the synthesis of propylene carbonate using CO2 and propylene oxide as starting materials. Different amides (i.e., acrylamide, benzamide, nicotinamide, acetamide, N-isopropylacrylamide, N-tert-butylacrylamide, and N,N-dimethylacrylamide) were combined with different potassium halides to investigate their catalysis capability. KI/acrylamide showed the highest efficiency, and a synergetic effect occurred between acrylamide and KI. At the KI: acrylamide ratio of 1:1 (mol/mol) and concentration of 2.5 mol% for both of them (based on PO), the reaction reached a yield of 95.3%. The catalytic system applies to the cycloaddition reaction using different epoxides. The reaction mechanism was proposed.

Enhancing the Catalytic Performance of Group I, II Metal Halides in the Cycloaddition of CO2 to Epoxides under Atmospheric Conditions by Cooperation with Homogeneous and Heterogeneous Highly Nucleophilic Aminopyridines: Experimental and Theoretical Study

“…Interestingly, halides such as NaI and KI can be extracted from waste biomass such as seaweed . Nevertheless, group I halides, when used alone, are sluggish catalysts for the target reaction ,− due to poor solubility and low Lewis acidity, and they require the assistance of or activation by additional catalytic components; potassium iodide has been frequently applied as a source of nucleophilic halides in the presence of catalytic components such as amino acids , and other homogeneous ,, or heterogeneous ,− hydrogen bond donors, N-heterocyclic carbenes, , crown ethers, and others . However, the reaction conditions associated with such systems are generally relatively harsh, especially in the case of partially heterogeneous systems where the additional, and often more expensive, catalytic moiety is recovered (80–120 °C, 10–20 bar CO 2 ). ,, This is even more the case of sodium halides as their application in the solventless cycloaddition of CO 2 to epoxides is relatively uncommon and generally requires high reaction temperatures (120–130 °C) and pressures (20–40 bar) − to afford reasonable to high yields of cyclic carbonates.…”

From Impossible to Possible: Atom‐Economic Polymerization of Low Strain Five‐Membered Carbonates

“…The five-membered propylene carbonate (PC) would be a desirable candidate, benefited from its wide sources (renewable CO 2 ), easy accessibility, low toxicity and broad application. [22,23] With increasing attention focused on the CO 2 utilization, [24][25][26][27][28][29][30][31] a huge amount of PC accumulates, which emphasizes the importance of further value-added transformation of PC. However, owing to its low strain energy, ROP of PC was reported to only afford a mixture of oligomers and substantial unidentified by-products (Figure 1a).…”

Potassium‐ion‐bound porous organic polymers having crown ether struts enable cooperative conversion of CO2 to cyclic carbonates under mild conditions

“…22 Nevertheless, the unique and flexible structures of crown ethers generally result in low porosity and poor stability of POPs, 23 thus fabricating tailored POPs with additional active sites still remains a challenge. [24][25][26] In the case that KI acts as the most frequently used alkali metal salt catalyst in the CO 2 cycloaddition reactions, [27][28][29][30][31][32][33][34][35] herein, a series of potassium-ion-bound POPs having crown ether struts (denoted as KI@CE-POPs) have been successfully synthesized through a continuous two-step process of Schiff-base condensation reaction and post-complexation, which is described in Scheme 1. The as-obtained POPs with 18-crown-6 components present remarkable binding ability of potassium ion due to the size-fit effect, which may be served as recyclable supports of catalysts.…”

“…In the case that KI acts as the most frequently used alkali metal salt catalyst in the CO 2 cycloaddition reactions, 27–35 herein, a series of potassium‐ion‐bound POPs having crown ether struts (denoted as KI@CE‐POPs) have been successfully synthesized through a continuous two‐step process of Schiff‐base condensation reaction and post‐complexation, which is described in Scheme 1. The as‐obtained POPs with 18‐crown‐6 components present remarkable binding ability of potassium ion due to the size‐fit effect, which may be served as recyclable supports of catalysts.…”