Search

Quaternary phosphine type hypercrosslinked polymer catalysts were successfully prepared using the Friedel–Crafts alkylation reactions, which benefit from the synergistic effects between the Brønsted acidity of the hydroxyl group and nucleophilicity of the Br− group as well as the CO2 capture of the ionic liquids. The as-obtained metal-free catalysts facilitate the cycloaddition and synthesis of high value-added fine chemicals. [ABSTRACT FROM AUTHOR]

Tannic acid (TA)/KI as a cheap, green, highly-efficient, biocompatible, and recyclable catalytic system represents the excellent synergistic effect in the cycloaddition reactions of CO2 and epoxides under solvent-free conditions, which is originated from hydrogen bonding between the hydrogen atoms of phenolic hydroxyl groups within TA and the oxygen atom of the epoxide. Therefore, it is considerable to be a sustainable methodology for the utilization of bio-resources. [ABSTRACT FROM AUTHOR]

A series of new metallosalen-based ionic porous organic polymers (POPs) were synthesized for the first time using a simple unique strategy based on the free-radical copolymerization reaction. Various techniques were used to characterize the physicochemical properties of these catalysts. These well-designed materials endowed high surface area, hierarchical porous structures, and enhanced CO2/N2 adsorptive selectivity. Moreover, these POPs having both metal centers (Lewis acid) and ionic units (nucleophile) could serve as bifunctional catalysts in the catalytic conversion of CO2 into high value-added chemicals without any additional co-catalyst under mild and solvent-free conditions, for example, CO2/epoxides cycloaddition and Nformylation of amines from CO2 and hydrosilanes. The results demonstrated that the irregular porous structure was very favorable for the diffusion of substrates and products, and the microporous structural property resulted in the enrichment of CO2 near the catalytic centers in the CO2-involved transformations. Additionally, the superhydrophobic property could not only enhance the chemoselectivity of products but also promote the stability and recyclability of catalysts. [ABSTRACT FROM AUTHOR]

A simple cooperative catalytic system was successfully developed for the solvent-free N-formylation of amines with CO2 and hydrosilanes under ambient conditions, which was composed of a Zn(salen) catalyst and quaternary ammonium salt. These commercially available binary components activated the Si−H bonds effectively, owing to the intermolecular synergistic effect between Lewis base and transition metal center (LB-TM), and subsequently facilitated the insertion of CO2 to form the active silyl formats, thereby leading to excellent catalytic performance at a low catalyst loading. Furthermore, the bifunctional Zn(salen) complexes, with two imidazolium-based ionic-liquid (IL) units at the 3,3′-position of salen ligand, acted as intramolecularly cooperative catalysts, and the solvent-regulated separation resulted in facile catalyst recycling and reuse. [ABSTRACT FROM AUTHOR]

A series of metalloporphyrin-based hyper-crosslinked polymers (M-HCPs: M=Al, Co, Fe, Mn) has been directly synthesized through Friedel-Crafts alkylation reactions. The M-HCPs afforded abundant permanent nanopores, high Brunauer-Emmett-Teller (BET) surface area, and exceptional CO2/N2 adsorptive selectivity. The experimental results suggested that the hollow tubular Al-HCP exhibited extraordinary catalytic performance in the solvent-free synthesis of cyclic carbonates from epoxides and CO2 by using tetrabutylammonium bromide as a cocatalyst under mild conditions, which was clearly superior to the corresponding homogeneous analogue. Surprisingly, a high turnover frequency (TOF) value of 14 880 h−1 was achieved with propylene oxide at 100 °C and 3.0 MPa, which was a promising result for industrial production compared with previously reported heterogeneous catalysts. More interestingly, Al-HCP could smoothly catalyze the cycloaddition reaction, producing the corresponding cyclic carbonates by using simulated flue gas (15 % CO2 and 85 % N2 in volume) as the raw material under ambient conditions. Moreover, Al-HCP could be readily recycled and efficiently reused more than ten times, exhibiting excellent stability. [ABSTRACT FROM AUTHOR]

A series of new metallosalen-based ionic porous organic polymers (POPs) were synthesized for the first time using a simple unique strategy based on the free-radical copolymerization reaction. Various techniques were used to characterize the physicochemical properties of these catalysts. These well-designed materials endowed high surface area, hierarchical porous structures, and enhanced CO 2 /N 2 adsorptive selectivity. Moreover, these POPs having both metal centers (Lewis acid) and ionic units (nucleophile) could serve as bifunctional catalysts in the catalytic conversion of CO 2 into high value-added chemicals without any additional co-catalyst under mild and solvent-free conditions, for example, CO 2 /epoxides cycloaddition and Nformylation of amines from CO 2 and hydrosilanes. The results demonstrated that the irregular porous structure was very favorable for the diffusion of substrates and products, and the microporous structural property resulted in the enrichment of CO 2 near the catalytic centers in the CO 2 -involved transformations. Additionally, the superhydrophobic property could not only enhance the chemoselectivity of products but also promote the stability and recyclability of catalysts., (© 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

A simple cooperative catalytic system was successfully developed for the solvent-free N-formylation of amines with CO 2 and hydrosilanes under ambient conditions, which was composed of a Zn(salen) catalyst and quaternary ammonium salt. These commercially available binary components activated the Si-H bonds effectively, owing to the intermolecular synergistic effect between Lewis base and transition metal center (LB-TM), and subsequently facilitated the insertion of CO 2 to form the active silyl formats, thereby leading to excellent catalytic performance at a low catalyst loading. Furthermore, the bifunctional Zn(salen) complexes, with two imidazolium-based ionic-liquid (IL) units at the 3,3'-position of salen ligand, acted as intramolecularly cooperative catalysts, and the solvent-regulated separation resulted in facile catalyst recycling and reuse., (© 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)