Adenine-assisted synthesis of functionalized F-Mn-MOF-74 as an efficient catalyst with enhanced catalytic activity for the cycloaddition of carbon dioxide

Boosting CO2 Conversion with Terminal Alkynes by Molecular Architecture of Graphene Oxide-Supported Ag Nanoparticles

Development of heterogeneous catalysts for the cycloaddition of CO2 with epoxides to produce cyclic carbonates is a hot issue in the field of chemical fixation of carbon dioxide. It is fairly promising as production of by-products is quite low. In this study, the [Zn3(BTC)2]/n-Bu4NBr catalytic system was investigated for the solventless cycloaddition of carbon dioxide with epoxides and had an excellent synergetic effect in promoting the reaction. The reaction parameters were moderate i.e. (130 °C and 13 bar CO2 pressure) and were selected by a study of the catalytic system. Under the optimal reaction conditions, the yield of cyclic carbonate reached 99%. A decrease in the yield of cyclic carbonate was not apparent after [Zn3(BTC)2] was reused three times, indicating that [Zn3(BTC)2] was stable. At the same time, the catalytic activity of the catalyst for other epoxides was also verified. The acidic and alkaline nature of the [Zn3(BTC)2] catalyst did not change obviously after recycling the catalyst three times. In this study it is also verified that the [Zn3(BTC)2] catalytic cycloaddition reaction was closely related to the Lewis acid/base distribution. In addition, a plausible mechanism for the synergistic effect of the catalyst (Lewis acid and base properties) and the co-catalyst was suggested.

Synthesis of cyclic carbonate from carbon dioxide and diols over metal acetates

An easily recoverable and efficient natural biopolymer-supported zinc chloride catalyst system for the chemical fixation of carbon dioxide to cyclic carbonate

Metal–organic materials are an important class of heterogeneous catalytic materials that offer a variety of organic transformations. A 2D azide functionalized copper(ii)-carboxylate framework (FCCF) was synthesized for catalytic application in the chemical fixation of carbon dioxide. The synthesized MOF was characterized using different techniques, i.e., FTIR, PXRD, SEM and TGA. Hirshfeld surface analysis was performed to assess intermolecular interactions. The catalytic potential of the FCCF for CO2 fixation to synthesize organic cyclic carbonates was investigated and optimized under solvent-free conditions and ambient CO2 pressure at 100 °C within 3–8 hours in the presence of a co-catalyst (tetrabutyl ammonium bromide). The complete conversion of epichlorohydrin into its cyclic carbonate with maximum selectivity was achieved under optimal reaction conditions. The FCCF as a functionalized material exhibited efficient fixation of carbon dioxide. The reaction mechanism for the cycloaddition of CO2 to epoxide catalyzed by the FCCF was investigated in detail based on experimental inferences and corroborated with the periodic calculations of density functional theory (DFT). Energy calculations depict that the azide-functionalized MOF material (FCCF) efficiently converts CO2 and epoxides into targeted cyclic carbonates. Therefore, the FCCF is an interesting material for the chemical fixation of CO2 for developing value-added chemical products.

Zeolitic imidazolate framework-68 as an efficient heterogeneous catalyst for chemical fixation of carbon dioxide

Combination of experimental and theoretical methods to explore the amino-functionalized pyrazolium ionic liquids: An efficient single-component catalyst for chemical fixation of CO2 under mild conditions

The catalysts of COOH- and SO3H-functionalized ionic liquids mediated metallic salts had been developed for the coupling of carbon dioxide and epoxides to form cyclic carbonates under mild reaction conditions without using additional organic solvents. The effects of different ionic liquids, metallic salts, varying the molar ratio of ionic liquid to metallic salt and reaction conditions were examined. The excellent yield of cyclic carbonates and the high turnover frequencies (TOF) were obtained at the optimum reaction conditions. In addition, the catalytic system offered high stability and reusability. The catalysts of Bronsted acidic ionic liquids mediated metallic salts had been developed for the coupling of carbon dioxide and epoxides to form cyclic carbonates with significant catalytic activity under mild reaction conditions. Additional, this catalyst system also offers the advantages of recyclability and reusability.

Design catalytic space engineering of Ag-Ag bond-based metal organic framework for carbon dioxide fixation reactions

Immobilized protic ionic liquids: Efficient catalysts for CO2 fixation with epoxides

New aluminium scorpionate based complexes have been prepared and used for the synthesis of cyclic carbonates from epoxides and carbon dioxide. Bimetallic aluminium(heteroscorpionate) complexes 9-14 were synthesised in very high yields. The single-crystal X-ray structures of 12 and 13 confirm an asymmetric κ(2)-NO-μ-O arrangement in a dinuclear molecular disposition. These bimetallic aluminium complexes were investigated as catalysts for the synthesis of cyclic carbonates from epoxides and carbon dioxide in the presence of ammonium salts. Under the optimal reaction conditions, complex 9 in combination with tetrabutylammonium bromide acts as a very efficient catalyst system for the conversion of both monosubstituted and internal epoxides into the corresponding cyclic carbonates showing broad substrate scope. Complex 9 and tetrabutylammonium bromide is the second most efficient aluminium-based catalyst system for the reaction of internal epoxides with carbon dioxide. A kinetic study has been carried out and showed that the reactions were first order in complex 9 and tetrabutylammonium bromide concentrations. Based on the kinetic study, a catalytic cycle is proposed.

Classical molecular dynamics were carried out in order to obtain insights into proper conditions to perform chemical fixation of carbon dioxide (CO2) with epoxide molecules into cyclic carbonates. Two different molecules containing epoxide groups were investigated: 1,2–Epoxybutane (EB), called linear aliphatic epoxide molecule, and 3-Ethyl-7-oxabicyclo(4.1.0)heptane (EC), called cycloaliphatic epoxide molecule. The reaction systems involving carbon dioxide additionally were catalyzed by tetraethylammonium bromide (TEAB). The dynamics of the molecular groups were studied by taking into account known reaction mechanisms to investigate whether the optimal reaction conditions were observed. Radial distribution functions and self-diffusion coefficients were calculated and revealed that in case of the systems with cycloaliphatic epoxide groups as reagent the CO2 molecules were located far away from the agglomerate formed by the dispersed tetraethylammonium bromide catalyst and epoxide groups (EC), and they do not present enough mobility to overcome the long distances to react. Additionally, it was observed that, in the case of the linear aliphatic epoxide groups (EB), the dynamics of the groups tends to facilitate the reaction mechanisms by presenting a considerable amount of available CO2 molecules in the neighborhood of the epoxy rings. Thus, via the Molecular Dynamics insights, the systems containing linear aliphatic epoxide groups presented a much more accessible condition for the subsequent reaction steps of the carbon dioxide fixation to occur as compared to systems containing cycloaliphatic epoxide groups. The simulation results are in agreement with the experimental findings, which showed via infrared spectroscopy the successful conversion of epoxy rings from linear aliphatic epoxide molecules into five-membered cyclic carbonates after reacting with carbon dioxide.

Immobilized ionic liquid/zinc chloride: Heterogeneous catalyst for synthesis of cyclic carbonates from carbon dioxide and epoxides

Cellulosic poly(ionic liquid)s ([Cellmim][Br]) with a degree of substitution (DS) in the range of 0.32–0.89 were synthesized successfully via the homogeneous transesterification reaction of cellulose with 1-(2-methoxyacetyl)-3-methyl imidazole bromide IL ([Mmim][Br]) in a DBU/DMSO/CO2 solvent system. The structure and properties of these novel materials have been fully characterized. Cellulosic poly(ionic liquid) POF polymers (POF-[Cellmim][Br]) were then obtained by an in situ crosslinking reaction without adding an exterior catalyst. The porosity and properties of the POF-[Cellmim][Br] materials can be modulated. The POF-[Cellmim][Br] materials functioned as green, efficient, and highly active catalysts for cycloaddition reactions of epoxides and carbon dioxide under solvent-free and co-catalyst-free conditions. These reactions gave high yields (up to 97%), and the catalyst can be easily separated with excellent reusability and no significant change to its structure. A plausible reaction mechanism for the cycloaddition reaction of epoxide and carbon dioxide by the POF-[Cellmim][Br] catalyst is proposed based on the experimental results. This work provided a new strategy to prepare cellulosic-PIL POF materials and offered a platform to understand the cooperative effects of porous properties and nucleophilic anions on the cycloaddition reaction of carbon dioxide and epoxides.

Chemical fixation of carbon dioxide (CO2) may be a pathway to retard the current trend of rapid global warming. However, the current economic cost of chemical fixation remains high because the chemical fixation of CO2 usually requires high temperature or high pressure. The rational design of an efficient catalyst that works at ambient conditions might substantially reduce the economic cost of fixation. Here, we report the rational design of covalent organic frameworks (COFs) as efficient CO2 fixation catalysts under ambient conditions based on the finding of “pore enrichment”, which is concluded by a detailed investigation of the 10994 COFs. The best predicted COF, Zn-Salen-COF-SDU113, is synthesized, and its efficient catalytic performance for CO2 cycloaddition to terminal epoxide is confirmed with a yield of 98.2% and turnover number (TON) of 3068.9 under ambient conditions, which is comparable to the reported leading catalysts. Moreover, this COF achieves the cycloaddition of CO2 to 2,3-epoxybutane under ambient conditions among all porous materials. This work provides a strategy for designing porous catalysts in the economic fixation of carbon dioxide.