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Fixing the greenhouse gas CO2 through epoxide helps to mitigate worldwide ecological troubles. The applications of metal‐free and solvent‐free catalysts remain a challenge for CO2 catalytic conversion. In this work, an array of quaternary ammonium salts derived from polyethyleneimine with hydroxyl groups ([PEI‐GDMAB‐Cn]Br) were constructed by the reaction of branched PEI with a molecular weight of 10000 and glycidyl alkyl dimethylammonium bromide. A range of experiments were designed to demonstrate that [PEI‐GDMAB‐Cn]Br can be considered as a valid metal‐free and solvent‐free homogeneous catalyst for the CO2‐epoxide cycloaddition reaction. Among of [PEI‐GDMAB‐Cn]Br, [PEI‐GDMAB‐C18]Br catalyzed the model reaction of CO2 and epichlorohydrin under optimized reaction conditions (T=80 °C, 1.0 atm CO2, catalyst 1 mol%, ECH 15 mmol, 16 h) and the conversion achieved at 97.5 %. Moreover, the catalyst exhibited stable reusability and broad substrate applicability, which was used in the following cycle succinctly, because of self‐separated properties by temperature control. The [PEI‐GDMAB‐C18]Br catalyzed reaction process was detected as a pseudo‐first‐order reaction after kinetic studies and an Ea was calculated to be 50.65 kJ/mol. A combinatorial catalytic mechanism of hydrogen bonding and bromide ions is suggested to explain the remarkable catalytic performance of this bifunctional catalyst. [ABSTRACT FROM AUTHOR]

A series of carbon sphere supported with adjustable alkyl length substitutes polymeric ionic liquids bearing hydroxylamino-anchored functional groups by covalent connection were fabricated from copolymerization of carbon sphere with vinyl based monomeric ionic liquids, which were constructed from 1-glycidyl-3-vinylimidazolium bromide and alkyl amines. The carbon sphere hybrid polymeric ionic liquids were characterized by FT-IR, SEM–EDS, N2 adsorption/desorption isotherm, elemental analysis, 13C MAS NMR and XPS, which were candidated as heterogeneous catalysts for CO2-epoxide cycloaddition reactions to product cyclic carbonates at mild conditions without co-catalyst and metal ion. The introduced functional groups on carbon sphere could accelerate the reaction process and yields of above 90% were obtained for various cyclic carbonates under optimized conditions. Finally, kinetic experiments were also carried out to reveal reaction mechanism and the activated energy was determined as 114.9 kJ/mol. Therefore, this study provides a new approach to fabricate multifunctional heterogeneous materials for coupling reaction of CO2 under mild conditions. [ABSTRACT FROM AUTHOR]

[Display omitted] • The SP-COPs exhibited high catalytic efficiency of CO 2 conversion and excellent I 2 adsorption capacity. • The synergistic mechanism of CO 2 conversion was proved by experimental and kinetics. • The iodine adsorption kinetic process was described. The fixing reactions of carbon dioxide with epoxides will not only help to ameliorate the problem of global warming, but also facilitate the synthesis of cyclic carbonates that have a multitude of applications. Herein, a new sequence of Salen cobalt complexes adjusted with different counterions and interconnected with pyrene group were synthesized through Friedel–Crafts alkylation, which were served as conjugated organic polymers (SP-COPs) for taking advantage of catalytic CO 2 fixation reactions and iodine adsorption. Further characterizations were carried out through FT-IR, UV, TGA, and SEM to comprehend the intact structure, thermal stability, morphology and other physical and chemical properties. All materials exhibited effective catalytic performance, and in particular, SP-COP-1 with co-catalyst of TBAI achieved 96.2% conversion under ultra-mild conditions. The E a was obtained to be 46.4 kJ·mol−1 by performing kinetic experiments at different temperatures by fitting the experimental data. The performance of iodine vapor adsorbed by these materials at ambient pressure of 75°C reached 2.8 g·g−1, 2.2 g·g−1 and 2.6 g·g−1 respectively, and the adsorption process is describable in terms of pseudo-first-order and pseudo-second-order adsorption kinetics. [ABSTRACT FROM AUTHOR]

A coordination polymeric crystal 1 was successfully synthesized from H 4 L (5,5′-(1,4-phenylenebis (methoxy))diisophthalic acid), bidpe (4,4′-bis(lmidazolyl)diphenyl ether), and Zn(NO 3) 2 ·6H 2 O under solvothermal conditions, and characterized by single-crystal X-ray diffraction. Then, two new crystals 1 Fe and 1 Cu were obtained with metal ion exchange when 1 was dipped into the DMF solution for FeCl 2 and CuCl 2 , respectively. The exchange process demonstrated that the high valence metal ion with strong acidity could be destroyed the structure of the crystals. Therefore, it should be exchanged with lower valence ion and then oxidized to the high valence state, which could be a feasible way to obtain the crystals with high valence metal ions. Further, the magnetic property and the synergistic CO 2 conversion with epoxide for 1 Fe and 1 Cu were also investigated, and the results shown that 1 Fe could be regarded as a potential catalyst for this conversion. Three two dimensional two-fold interpenetrated MOFs 1 , 1 Fe and 1 Cu were successfully synthesized via solvothermal or post-synthetic modification. 1 Fe and 1 Cu shown excellent abilities for catalyzed cycloaddition of CO 2 to epoxides. [Display omitted] 1. Three novel dimensional MOFs 1 , 1 Fe and 1 Cu , have been synthesized via solvent-thermal treatment and post-synthetic exchange approach. 2. Zn(II) ions were exchange with Fe(III) ions in 1 Fe. But, due to the strong acidity of Fe(III) ions could destroy the crystal framework, the exchange only could be happen when 1 was dipped into the freshly FeCl 2 -DMF solution. 3. Variable-temperature magnetic studies indicate that 1 Fe contains the weak ferromagnetic chain while 1 Cu contains the weak antiferromagnetic (AF) interactions. 4. The catalytic properties of 1 , 1 Fe and 1 Cu for epoxides' cycloaddition reactions with CO 2 , and the results shown that 1 Fe and 1 Cu could be good catalysts for this reaction. [ABSTRACT FROM AUTHOR]