Synthesis of a Pyridine–Zinc‐Based Porous Organic Polymer for the Co‐catalyst‐Free Cycloaddition of Epoxides

Abstract

The synthesis of solid catalysts for the co-catalyst-free cycloaddition of CO has attracted much attention. Herein, we report a hierarchical porous organic polymer, Py-Zn@MA, that is able to catalyze the cycloaddition reaction of epoxides and CO without using any additives or co-catalyst to afford turnover frequency (TOF) values as high as 250 and 97 h at 130 °C by using pure and diluted CO (simulating flue gas), respectively. These results are superior to those obtained from previously reported heterogeneous co-catalyst-free systems. The high activity of Py-Zn@MA is mainly attributed to its bifunctional nature with ZnBr and pyridine activating the epoxide in a cooperative way. Notably, Py-Zn@MA can be easily prepared on a large scale without using any catalyst and the chemicals are cost effective. Moreover, Py-Zn@MA shows good substrate universality for the cycloaddition reactions of epoxides. Our designed porous organic polymer Py-Zn@MA material has the potential to serve as an efficient catalyst for the direct conversion of flue gas with epoxides into value-added cyclic carbonates.

Imidazolium‐Functionalized Ionic Hypercrosslinked Porous Polymers for Efficient Synthesis of Cyclic Carbonates from Simulated Flue Gas

“…So far, a broad range of homogeneous and (semi‐)heterogeneous catalysts have been applied for the coupling of CO 2 with epoxides, covering ionic liquids (ILs), metal halides/complexes, porous organic polymers (POPs), metal–organic frameworks (MOFs), as well as carbon materials such as carbon nanotubes (CNTs) and carbon nanohorns (CNHs) . Some of these were also explored in the reaction of epoxides with diluted CO 2 , mimicking flue gases .…”

“…Azo‐polymer‐supported ZnBr 2 exhibited a synergistic effect between metal salt and support in the cycloaddition of CO 2 /N 2 mixtures with various epoxides by using the organic nucleophile TBAB and ethanol as solvent . Compared with the homogeneous analogues, heterogeneous catalysts are advantageous for facile operation, separation, and recycling . However, additives are usually involved in many systems for the capture and conversion of diluted CO 2 by coupling with epoxides .…”

“…Compared with the homogeneous analogues, heterogeneous catalysts are advantageous for facile operation, separation, and recycling . However, additives are usually involved in many systems for the capture and conversion of diluted CO 2 by coupling with epoxides . In addition, metal‐based catalysts may increase the risk of metal leaching, which would result in potential environmental contamination and complicate the product purification .…”

Cationic Zn-Porphyrin Immobilized in Mesoporous Silicas as Bifunctional Catalyst for CO2 Cycloaddition Reaction under Cocatalyst Free Conditions

“…The CO 2 cycloaddition reaction is of great importance not only because cyclic carbonates are value-added fine chemicals but also because conversion of CO 2 to fuels and chemicals has attracted much research attention due to rapid consumption of fossil energy and environment problems. − Many heterogeneous catalysts have been developed and used in CO 2 cycloaddition reactions due to the advantages of easy handling, facile separation of catalysts and products, and possible catalysts recycling. − However, most reported heterogeneous catalysts afforded desirable activity only in the presence of nucleophilic cocatalyst, such as immobilized metal complexes, − metal-free catalysts, , metal–organic frameworks (MOFs), − porous organic polymers (POPs), − etc. It is still a significant challenge to recover molecular cocatalyst from the reaction solution.…”

Enhancement in the active site exposure in a porphyrin-based PIL/graphene composite catalyst for the highly efficient conversion of CO2

“…6 and Table S3 †). 26,[60][61][62][63][64][65][66][67][68][69][70][71] This could be attributed to many reasons: (1) rich Lewis acid metal sites and bromine ions (as nucleophiles) are embedded into the material framework, which facilitated the rapid ring-opening of epoxides to generate highly active intermediates under the synergistic catalysis. (2) In the structural PIL, porphyrins are directly bridged by pyridine IL units, avoiding the introduction of invalid linking groups which facilitates the availability of the maximum number of catalytic active sites.…”