Synthesis Of Cyclic Carbonates Research Articles

Aerobic Oxidative Carboxylation of Styrene Over Cobalt Catalysts: Integrated CO2 Capture and Conversion.

The direct synthesis of cyclic carbonates through oxidative carboxylation of alkenes using CO2 and O2 offers a sustainable and carbon-neutral method for CO2 utilization, which is, however, still a largely unexplored field. Here we develop a single-atom catalyst (SAC) Co-N/O-C as the earth-abundant metal catalyst for the oxidative carboxylation of styrene with CO2 and O2. Remarkably, even using the flue gas as an impure CO2 and O2 source, desired cyclic carbonate could be obtained with moderate productivity, which shows the potential for integrated CO2 capture and conversion, leveraging the high CO2 adsorption capacity of Co-N/O-C. In addition, the catalyst can be reused five times without an obvious decline in activity. Detailed characterizations and theoretical calculations elucidate the crucial role of single Co atoms in activating O2 and CO2, as well as controlling selectivity.

On Sustainability Aspects of the Synthesis of Five-Membered Cyclic Carbonates

On Sustainability Aspects of the Synthesis of Five-Membered Cyclic Carbonates

Salophen-type Organocatalysts for the Cycloaddition of CO2 and Epoxides under Solvent, Halide, and Metal-Free Conditions.

8-Formyl-7-hydroxycoumarin (A) and their derived salophen-type organocatalysts L1, L2, and L3 were used for the synthesis of cyclic carbonates from carbon dioxide (CO2) and epoxides under solvent-, halide-, and metal-free conditions. According to previous optimization tests, L1 and L2 had the best catalytic activity presenting 89 and 92% conversion toward the synthesis of 3-chloropropylene carbonate (2c) using 8 bar CO2, 100 °C at 9 h. Therefore, they were used as organocatalysts to complete the catalytic screening with 11 terminal epoxides (1a-k) exhibiting the highest TOF values of 20 and 22 h-1 using 1c and 1b, respectively. Similarly, they were tested with an internal epoxide, such as cyclohexene oxide (1l) exhibiting 72% conversion, becoming the first salophen organocatalyst to obtain cis-cyclohexane carbonate (2l) in the absence of a cocatalyst. In addition, a reaction mechanism was proposed for the formation of cyclic carbonates based on experimental data and computational techniques; these contributed in establishing a probable role of CO2 pressure along the catalysis and the hydrogen bonds that favor the stabilization of the different intermediates of the reaction.

Experimental and kinetic evaluation on cobalt Salen conjugated organic polymers for CO2 cycloaddition reactions and iodine vapor adsorption

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 CO2 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 Ea 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.

Cyclic carbonate synthesis from CO2 and epoxides catalyzed by lanthanide derivatives comprising arylhydrazones of β-diketones

Two known lanthanide complexes, [KLa(HL1)2{(CH3)2NCHO}2(H2O)3] (1) and [Sm(H2O)9](E-H2L2)3·2H2O (2), (KH2L1 = potassium 3-(2-(2,4-dioxopentan-3-ylidene)hydrazinyl)-2-hydroxy-5-nitrobenzenesulfonate, KH2L2 = potassium (E,Z)-5-chloro-3-(2-(1,3-dioxo-1-phenylbutan-2-ylidene)hydrazinyl)-2-hydroxybenzenesulfonate), have been prepared and tested as catalysts in the cycloaddition of CO2 with epoxides in the presence and absence of co-catalysts (tetrabutylammonium chloride (TBACl), tetrabutylammonium bromide (TBABr) and tetrabutylammonium iodide (TBAI)). Complex 1 was found to be the most efficient catalyst in the presence of TBABr, with conversions up to 97 %, at 40 °C, of the epoxides to the corresponding cyclic carbonates. The catalytic activity of 1 is dependent on the nature of the substrate, ranging from 23 to 97 %.

2D Co-Based Metal–Organic Framework Nanosheets for the One-Pot Synthesis of Cyclic Carbonates from Olefins and CO2

2D Co-Based Metal–Organic Framework Nanosheets for the One-Pot Synthesis of Cyclic Carbonates from Olefins and CO₂

Development of Silica‐Immobilized Material as Heterogeneous Hydrogen Bond Donor (HBD) Catalyst: Synthesis of Cyclic Carbonates from CO2 and Epoxides

AbstractComposite silica materials have been developed by hydrothermal method and utilized as heterogeneous Hydrogen Bond Donor (HBD) catalysts, where the functionalized ketimine derivatives have been immobilized on the solid support. Such functional materials have been found to be efficient catalysts for the synthesis of cyclic carbonates through the installation of CO2 with epoxides. Characterization of these materials was systematically done using various spectroscopic and imaging techniques to confirm the presence of organic compounds on the silica surface. These composite materials exhibited significantly higher catalytic activity as compared to the other homogeneous methods. Additionally, this synthetic process was extremely convenient in terms of all the external parameters such as, solvent free condition at ambient reaction temperature with normal pressure of CO2, very low catalyst loading with proper regeneration and reusability of the catalyst. These facets have definitely made this technique greener and more sustainable.

Modulating H‐bond Strength to Enhance Reactivity for Efficient Synthesis of Cyclic Carbonates with Tetrabutylammonium Iodide‐based Deep Eutectic Solvents

AbstractDeveloping a highly efficient and environmentally friendly catalytic system for CO2 cycloaddition reactions is an attractive way to achieve carbon neutrality. In this work, tetrabutylammonium iodide (TBAI) and polyethylene glycol (PEG) were used to produce novel deep eutectic solvents (DESs), which could serve as both solvents and catalysts, displaying excellent activity to synthesis styrene carbonates from CO2 and styrene oxide under metal‐free, cocatalyst‐free, solvent‐free and mild conditions. A detailed study was undertaken on the effects of reaction parameters, recyclability, and substrate scope. Additionally, the H‐bond interaction between the substrate and TBAI/PEG200 was thoroughly investigated using FT‐IR and 1H NMR techniques. The synergistic interaction between the two components of the DES, TBAI, and PEG200, may be the key to the high catalytic activity of this system. The tetrabutylammonium iodide‐based system is an innovative strategy for the CO2 cycloaddition with epoxides, achieved by elaborately devising the H‐bonds of DESs to enhance reactivity. This provides a novel green strategy for potential industrial applications.

Highly efficient synthesis of cyclic carbonates via deep eutectic solvents from CO2 at the gas-liquid interface of microdroplet under atmospheric pressure condition

The cycloaddition reaction of CO2 in traditional reactors is relatively slow due to insufficient gas–liquid contact. In this work, the microdroplet reactor was set up to research the intensification effect of increasing the volumetric mass transfer coefficient on the reaction. The [C1C2Im][I]/PhOH (1-ethyl-3-methylimidazolium iodide/Phenol) with a molar ratio of 2:1 exhibited excellent catalytic activity at room temperature. Up to 85% conversion of the substrate could be achieved in the microdroplet intensification device. The intensification reaction model of the microdroplet was established, which explored the effect of the microdroplet size and gas–liquid mass transfer on the reaction. The increase of the volumetric mass transfer coefficient (kLa) could improve the efficiency of the reaction at the gas–liquid interface of the microdroplet. The mathematical model of the microdroplet intensification reaction was established to clarify the intensification mechanism.

A Hierarchical Metal-Organic Framework Composite Aerogel Catalyst Containing Integrated Acid, Base, and Metal Sites for the One-Pot Catalytic Synthesis of Cyclic Carbonates.

Catalysis has played a decisive role in the development of unique chemical reactions to produce important chemicals. However, conventional stepwise synthetic routes that rely on individual catalysts to promote each step often suffer from ponderous processes for the isolation of intermediates that result in massive material losses and large economic expenditures. In addition, traditional powder forms of these catalysts suffer from poor processability and recoverability. Herein, we designed and prepared a hierarchical metal-organic framework (MOF) composite monolithic catalyst IL-Au@UiO-66-NH2/CMC that contains integrated acid (Zr4+), base (ionic liquid (IL)), and metal sites (Au nanoparticles (NPs)) to promote the one-pot preparation of cyclic carbonates from styrene derivatives and CO2. Highly dispersed Au NPs, IL 1-aminoethyl-3-methylimidazolium bromide ([C2NH2 MIM] [Br]), and MOF-positioned Lewis acid sites within this composite aerogel are separately responsible for catalyzing selective epoxidation of the styrene derivatives and the subsequent cycloaddition reaction of CO2 with intermediate styrene oxides. Importantly, inclusion of the imidazolium-based IL effectively modulates the size and chemical microenvironment of the Au NPs via electrostatic protection, leading to catalyst stability and its selective oxidation of styrene. Benefiting from the rapid mass transfer and high exposure of active sites within the pore-rich hierarchical nanostructure, IL-Au@UiO-66-NH2/CMC promotes high conversion (90.5%) of the styrene and selectivity (80.5%) for styrene carbonate (SC) formation in the one-pot process, a performance level that far exceeds those of related catalysts containing only Au NPs or IL (the selectivity of SC < 42%). Furthermore, the composite aerogel catalyst can be readily separated and recycled at least five times without a remarkable loss of activity and selectivity. The controllable integration of various active components in the hierarchical MOF composite aerogel herein should serve as the foundation for the design of multifunctional monolithic catalysts for other valuable tandem processes.

Carbon Dots as New Effective Catalysts for Knoevenagel Condensation Reaction and Synthesis of Cyclic Carbonates under Solvent‐free Conditions

AbstractCarbon dots (CDs) as new efficient catalysts have been developed for the Knoevenagel condensation reaction and the synthesis of cyclic carbonates under solvent‐free conditions. Six kinds of carbon dots with different numbers of amino groups were synthesized. The amine‐terminated carbon dot (NCDs‐1) was synthesized using arginine and ethylenediamine by a microwave technique, and its catalytic action was studied. NCDs‐1 with the highest numbers of amino groups was used as new metal‐free and effective heterogeneous catalysts to perform essential Knoevenagel condensation and cycloaddition reactions in solvent‐free conditions. 1H NMR was used to demonstrate the Knoevenagel condensation mechanism, in situ Fourier infrared spectroscopy was used to investigate CO2 cycloaddition and a catalytic mechanism was postulated. NCDs‐1 showed a yield of 96.3±1.5 % for Knoevenagel condensation of benzaldehyde and malononitrile. In addition, NCDs‐1/TBAB showed a yield of (97.0±1.0 %) of 4‐phenyl‐1,3‐dioxolan‐2‐one for styrene oxide at 100 °C and 0.1 MPa in 1.5 h. A simple and convenient method for catalytic reactions with amine‐terminated carbon dots was developed.

Organocatalysts for the Synthesis of Cyclic Carbonates under the Conditions of Ambient Temperature and Atmospheric CO2 Pressure

2–(1H–1,2,4–Triazol–3–yl)phenol (CAT–1) was used as an organocatalyst for the coupling reaction of CO2 and epoxides at an ambient temperature and atmospheric CO2 pressure (1 bar). This compound has a structure in which a hydrogen bond donor, a hydrogen bond acceptor, and another hydrogen bond donor are adjacent in sequence in a molecule. The binary catalytic system of CAT–1/nBu4NI showed TON = 19.2 and TOF = 1.60 h−1 under 1 bar CO2 at room temperature within 12 h using 2–butyloxirane. Surprisingly, the activity of CAT–1, in which phenol and 1H–1,2,4–triazole are chemically linked, showed a much greater synergistic effect than when simply mixing the same amount of phenol and 1H–1,2,4–triazole under the same reaction conditions. In addition, our system showed a broad terminal and internal epoxide substrate scope.

Ionic liquid post-modified carboxylate-rich MOFs for efficient catalytic CO2 cycloaddition under solvent-free conditions.

The synthesis of cyclic carbonates through cycloaddition reactions between epoxides and carbon dioxide (CO2) is an important industrial process. Metal-Organic Frameworks (MOFs) have functional and ordered pore structures, making them attractive catalysts for converting gas molecules into valuable products. One approach to enhance the catalytic activity of MOFs in CO2 cycloaddition reactions is to create open metal sites within MOFs. In this study, the amino-functionalized rare earth Gd-MOF (Gd-TPTC-NH2) and its ionic liquid composite catalysts (Gd-TPTC-NH-[BMIM]Br) were synthesized using 2'-amino-[1,1':4',1''-terphenyl]-3,3'',5,5''-tetracarboxylic acid (H4TPTC-NH2) as the ligand. The catalytic performance of these two catalysts was observed in the cycloaddition reaction of CO2 and epoxides. Under the optimized reaction conditions, Gd-TPTC-NH-[BMIM]Br can effectively catalyze the cycloaddition reaction of a variety of epoxide substrates with good to excellent yields of cyclic carbonate products. Comparatively, epichlorohydrin and epibromohydrin, which possess halogen substituents, promote higher yields of cyclic carbonates due to the electron-withdrawing nature of Cl and Br substituents. Additionally, the Gd-TPTC-NH-[BMIM]Br catalyst demonstrated good recyclability and reproducibility, maintaining its catalytic activity without any changes in its structure or properties after five reuse cycles.

Magnesium-porphyrin as an efficient photocatalyst for the transformation of CO2 to cyclic carbonates and oxazolidinones under ambient conditions

Herein, we report an efficient and simple photocatalytic system based on Mg-porphyrin for the synthesis of cyclic carbonates and oxazolidinones. As this reaction uses non-toxic, renewable, and widely available CO2, it promotes sustainability.

Turning waste into resources. Efficient synthesis of biopolyurethanes from used cooking oils and CO2

The coupling reaction of carbon dioxide and highly-substituted epoxides derived from renewable resources such as fatty acids and waste vegetable oils (cooking oils derived from olive and sunflower) leads to the synthesis of new bio-derived cyclic carbonates using efficient metal-free bifunctional organocatalysts under mild and solvent-free reaction conditions. Once cyclic carbonates derived from biobased sources were synthesized, the design of non-isocyanate polyurethanes (NIPUs) with different chemical structures was investigated by their reaction with a broad substrate scope of diamines. The NIPUs materials were characterized by spectroscopic techniques (NMR and IR) and their molecular weights and polydispersities were determined by GPC studies. Finally, thermal properties of the polymers were studied by DSC and TGA analyses.

Review on the recent advances in catalytic conversion of carbon dioxide for synthesis of cyclic propylene carbonate

Generation of carbondioxide in the atmosphere has increased considerably over the past decades due to the increase of industrialization. This led to the increase in the global temperature which affects the eco-system. It is essential to reduce the emission of carbondioxide in the atmosphere for which different researchers are working on re-utilization of the generated carbondioxide either by converting to different products or by trapping them as carbonates. Propylene carbonate is one of the chemicals that are synthesized by using CO2 as a reactant. Propylene carbonate has many applications as an end product and acts as intermediate for synthesis of other useful chemicals. Fixation of CO2 into propylene oxide for the synthesis of propylene carbonate is still a challenging task due to the high thermodynamic stability of CO2. Propylene carbonate can be synthesized by reacting CO2 with different high energy materials using different catalyst. This review is focused on providing an idea about different types of catalyst reported for synthesis of cyclic propylene carbonate using propylene oxide and propylene glycol as the starting materials. This review also provides the mechanism for conversion of CO2 to propylene carbonate by different catalyst and at various working conditions.

Combining bio- and chemo-catalysis for cyclic carbonate synthesis at very low pressure: Efficient “online” utilization of CO2 obtained directly from the fermentation of sugars

A very low-pressure set-up for the synthesis of cyclic carbonates and polycarbonates from epoxides/CO2 has been constructed using our previously reported Ga-catalyst. This set-up is based on the direct use of unpurified CO2 obtained from the fermentation of sugars, which exemplifies a potentially important advancement for the future application of this widely explored CO2 utilization reaction. Using this approach, it has been possible to produce cyclic carbonates with a high bio-derived atom content when starting from bio-based epoxides, such as, eugenol oxide. Use of alternative sources of sugar beyond sucrose have also been exemplified (grapes), highlighting the potential for direct coupling to important industrial fermentation processes which emit large amounts of CO2. Finally, use of 13C6-glucose as sugar-source has allowed for the preparation of 13C-containing cyclic carbonates, with the bis-cyclic carbonates being readily converted through reaction with a diamine to form 13C-labelled polymers (13C-Non-Isocyanate PolyUrethanes; 13C-NIPU’s).

Multi-Functional Polymer Membranes Enable Integrated CO2 Capture and Conversion in a Single, Continuous-Flow Membrane Reactor under Mild Conditions.

Herein, we present a membrane-based system designed to capture CO2 from dilute mixtures and convert the captured CO2 into value-added products in a single integrated process operated continuously under mild conditions. Specifically, we demonstrate that quaternized poly(4-vinylpyridine) (P4VP) membranes are selective CO2 separation membranes that are also catalytically active for cyclic carbonate synthesis from the cycloaddition of CO2 to epichlorohydrin. We further demonstrate that quaternized P4VP membranes can integrate CO2 capture, including from dilute mixtures down to 0.1 kPa of CO2, with CO2 conversion to cyclic carbonates at 57 °C and atmospheric pressure. The catalytic membrane acts as both the CO2 capture and conversion medium, providing an energy-efficient alternative to sorbent-based capture, compression, transport, and storage. The membrane is also potentially tunable for the conversion of CO2 to a variety of products, including chemicals and fuels not limited to cyclic carbonates, which would be a transformative shift in carbon capture and utilization technology.

AgNPs Embedded in Porous Polymeric Framework: A Reusable Catalytic System for the Synthesis of α-Alkylidene Cyclic Carbonates and Oxazolidinones via Chemical Fixation of CO2

AgNPs Embedded in Porous Polymeric Framework: A Reusable Catalytic System for the Synthesis of α-Alkylidene Cyclic Carbonates and Oxazolidinones via Chemical Fixation of CO2

Anion-rich porous poly(ionic liquid)s for efficient CO2 conversion into cyclic carbonates through hydrogen bonding synergistic effect

Ionic liquids have widely been recognized as highly effective catalysts for the synthesis of cyclic carbonates from CO2 and epoxides. However, the cumbersome separation process hinders the practical application of these catalysts. In this study, a strategy involving free radical polymerization was employed to successfully co-polymerized monomers of ionic liquid and divinylbenzene (DVB), resulting in the fabrication of anion-rich porous poly(ionic liquid)s (PILs) that incorporated a hydrogen bonding site of -NH2-+. The texture properties of the as-prepared PILs were characterized in detail, and they were then utilized as catalysts for the cycloaddition of CO2 and epoxides to form cyclic carbonates. Remarkably, the reaction exhibited a remarkable yield of up to 99 % under solvent- and metal-free conditions. It is noteworthy that PIL-2 demonstrated easy recoverability, with a slight reduction in catalytic activity of about 7 % after five cycles. Additionally, a mechanism based on hydrogen bond synergistic for the conversion of CO2 by anion-rich porous PILs was proposed. This study offers a valuable insight for the development of recyclable poly(ionic liquid)s catalysts for CO2 conversion.