Cycloaddition Of Carbon Dioxide Research Articles

Catalytic coupling of CO2 and epoxides with metal substituted Keggin based Hybrid Materials

Three hybrid catalytic materials are synthesised using transition metal (CoII, NiII, CuII) substituted lacunary Keggin polyoxometalates and tetrabutylammonium cations (TBA-TMSPOMs) and used for atom-economic cycloaddition of carbon dioxide to various epoxides producing cyclic carbonates under ambient conditions. These hybrid materials have been characterised by powder XRD, TGA, SEM, TEM, FTIR and 31P NMR. A rapid and effective method towards quantitative conversion of aliphatic, cyclic, and aromatic epoxides to their respective cyclic carbonates under solvent-free conditions is described. The percentage conversion of various epoxides into their respective cyclic carbonates is confirmed by 1H NMR and gas chromatography. Of all the cyclcoaddition reactions studied, the epichlorohydrin shows nearly 100% selectivity with turnover frequency of 244 h−1. Among the three hybrid catalysts, ∼0.12 mol% of TBA-PWCo is adequate to achieve highest catalytic efficiency with over 95% conversion in 4 h at RT. This catalyst is recyclable and reusable up to five cycles without significant loss in activity.

Air-Stable Cobalt(III) and Chromium(III) Complexes as Single-Component Catalysts for the Activation of Carbon Dioxide and Epoxides.

Cobalt(III) and chromium(III) salophen chloride complexes were synthesized and tested for the cycloaddition of carbon dioxide (CO2) with epoxides to obtain cyclic carbonates. The cat1, cat2, cat4, and cat5 complexes presented high catalytic activity without cocatalysts and are solvent-free at 100 °C, 8 bar, and 9 h. At these conditions, the terminal epoxides (1a-1k) were successfully converted into the corresponding cyclic carbonates with a maximum conversion of ∼99%. Moreover, cat5 was highlighted due to its capability of opening internal epoxides such as limonene oxide (1l) with a 36% conversion to limonene carbonate (2l), and from cyclohexene oxide (1m), cyclic trans-cyclohexene carbonate (2m) and poly(cyclohexene carbonate) were obtained with 15% and 85% selectivity, respectively. A study of the coupling reaction mechanism was proposed with the aid of electrospray ionization mass spectrometry (ESI-MS) analysis, confirming the single-component behavior of the complexes through their ionization due to epoxide coordination. In addition, crystallographic analysis of cat1 single crystals grown in a saturated solution of pyridine helped to demonstrate that the substitution of chloride ion by pyridine ligands to form an octahedral coordination occurs (Py-cat1), supporting the proposed mechanism. Also, a recyclability study was performed for cat5, and a total turnover number of 952 was obtained with only minor losses in catalytic activity after five cycles.

Aluminium-Based Metal-Organic Framework Nano Cuboids and Nanoflakes with Embedded Gold Nanoparticles for Carbon Dioxide Fixation with Epoxides into Cyclic Esters.

The fixation of carbon dioxide with epoxides is one of the most attractive methods for the green utilisation of this greenhouse gas and leads to many valuable chemicals. This process is characterised by 100% atom efficiency; however, an efficient catalyst is required to achieve satisfactory yields. Metal-organic frameworks (MOFs) are recognised as being extremely promising for this purpose. Nevertheless, many of the proposed catalysts are based on ions of rare elements or elements not entirely safe for the environment; this is notable with commercially unavailable ligands. In an effort to develop novel catalysts for CO2 fixation on an industrial scale, we propose novel MOFs, which consist of aluminium ions coordinated with commercially available 1,4-naphthalene dicarboxylic acid (Al@NDC) and their nanocomposites with gold nanoparticles entrapped inside their structure (AlAu@NDC). Due to the application of 4-amino triazole and 5-amino tetrazole as crystallization mediators, the morphology of the synthesised materials can be modified. The introduction of gold nanoparticles (AuNPs) into the structure of the synthesised Al-based MOFs causes the change in morphology from nano cuboids to nanoflakes, simultaneously decreasing their porosity. However, the homogeneity of the nanostructures in the system is preserved. All synthesised MOF materials are highly crystalline, and the simulation of PXRD patterns suggests the same tetragonal crystallographic system for all fabricated nanomaterials. The fabricated materials are proven to be highly efficient catalysts for carbon dioxide cycloaddition with a series of model epoxides: epichlorohydrin; glycidol; styrene oxide; and propylene oxide. Applying the synthesised catalysts enables the reactions to be performed under mild conditions (90 °C; 1 MPa CO2) within a short time and with high conversion and yield (90% conversion of glycidol towards glycerol carbonate with 89% product yield within 2 h). The developed nanocatalysts can be easily separated from the reaction mixture and reused several times (both conversion and yield do not change after five cycles). The excellent performance of the fabricated catalytic materials might be explained by their high microporosity (from 421 m2 g-1 to 735 m2 g-1); many catalytic centres in the structure exhibit Lewis acids' behaviour, increased capacity for CO2 adsorption, and high stability. The presence of AuNPs in the synthesised nanocatalysts (0.8% w/w) enables the reaction to be performed with a higher yield within a shorter time; this is especially important for less-active epoxides such as propylene oxide (two times higher yield was obtained using a nanocomposite, in comparison with Al-MOF without nanoparticles).

Highly efficient DES-based catalytic systems for carbon dioxide utilization via cycloaddition with epoxide substrates

The accumulation of greenhouse gases (GHG) in the atmosphere, with carbon dioxide being the most significant contributor, is a major environmental problem as it impacts significantly on climate change. The development of new catalysts and chemical reactions that incorporate CO2 are needed to reduce its further emission significantly. Deep eutectic solvents (DES) have garnered increasing attention as environmentally friendly catalysts in the cycloaddition of carbon dioxide (CO2) with epoxide substrates to produce cyclic carbonates. Their appeal stems from their facile synthesis, cost-effectiveness, low vapour pressure, and thermal stability. In this study, we present a convenient solvent-free synthesis method for nine deep eutectic solvents (DES), utilizing varying compositions of quaternary amine salts (N,N,N-triethyldodecan-1-aminium hydroxide, [TEA-12][OH]) and quinaldic acid [Q-COOH]. These deep eutectic solvents were thoroughly characterized using several techniques, including FTIR, NMR, DSC, and TGA. Moreover, their efficacy for the solvent-free fixation of CO2 to cyclic carbonates were evaluated. Among the tested compositions, [TEA-12]:[Q-COOH] (0.9:0.1) exhibited the lowest melting point (100.17 °C) and highest catalytic activity, showcasing an optimized Turn-Over Frequency (TOF) of 1466 h−1. This remarkable result represents a significant advancement in the application of DES for CO2 fixation, exceeding the previous highest catalytic activity observed with TBAB:Citric acid (2.5:1) by more than tenfold.

Calix[6]arene-functionalized titanium-oxo clusters for photocatalytic cycloaddition of carbon dioxide to epoxides

We synthesized the largest calixarene-stabilized titanium-oxo clusters reported to date, Ti28-TBC6A. It exhibits excellent photoelectronic performance and superior photocatalytic activity for CO2 fixation.

Tetracosanuclear nickel complexes as effective catalysts for cycloaddition of carbon dioxide with epoxides.

A series of well-defined tetracosanuclear nickel complexes 3-7 facilely produced by one-pot synthesis were active catalysts for cycloaddition of CO2 and cyclohexene oxide (CHO). These nickel complexes were doughnut-like supramolecular coordination complexes involving eight repeating units, and each of them contains one Schiff base ligand and three nickel(II) ions. Notably, the 24-nuclear nickel cluster complex 3 in combination with nucleophilic additives was the most efficient catalyst to mediate CO2 coupling with CHO to generate CO2-based cis-cyclohexene carbonates. In addition to CO2/CHO cycloaddition, complex 3 was also found to effectively couple CO2 with other alicyclic epoxides, generating the corresponding cyclic carbonates. Additionally, kinetic investigations for CO2 cycloaddition of CHO using 3 were reported.

Halide-free pyridinium base binary organocatalyst for the cycloaddition of carbon dioxide to epoxides

An organocatalyst composed of a common organic base and hydroxypyridine is a new type of H-bond donor catalyst efficient in the cycloaddition of CO2 to epoxides.

Salophen chromium(iii) complexes functionalized with pyridinium salts as catalysts for carbon dioxide cycloaddition to epoxides.

The catalytic properties of a series of novel chromium(iii) salophen complexes having different pyridinium chloride units (pyridinium, 2,6-dimethylpyridinium or 4-(dimethylamino)pyridinium ones) have been studied in the reaction of carbon dioxide cycloaddition to phenyl glycidyl ether. The examined complexes were found to be capable of catalyzing cycloaddition under relatively mild reaction conditions without any additional nucleophilic co-catalyst. However, their catalytic activity depended strongly on the structure and number of pyridinium salt units in the ligand molecule. The complex with a single unit of 4-(dimethylamino)pyridinium chloride turned out to be the most active among the examined ones. A TOF of up to 1480 h-1 was obtained in the presence of this catalyst under the following conditions: 120 °C, 2 h, 6 bar, 0.05 mol% (74% epoxide conversion, and >99% selectivity). The most active complex has also been examined as a catalyst in the reactions of CO2 with a series of ten other terminal epoxides. High catalytic activity (TOF = 220-5045 h-1) was observed in most cases, except for the reaction of CO2 with allyl glycidyl ether.

Efficient CO2 fixation under atmospheric pressure using a metal- and halide-free heterogeneous catalyst

Pyrimidine based polymers are reported for CO2 adsorption studies. 1,3,5-triaminopyrimidine-based polymer using cheap linker terephthaldehyde is design and employed for the metal- and halide-free carbon dioxide cycloaddition reaction with epoxides.

Designed synergetic bifunctional catalyst based on diverse nucleophilic-functionalized sites for high-efficient CO2 cycloaddition under co-catalyst and solvent-free conditions

Nucleophilic substitutes provide a new platform to design and synthesize novel bifunctional heterogeneous catalysts for carbon dioxide cycloaddition reaction with epoxides. Herein, in this work, UMCM-15 was fabricated and modified with various nucleophilic ligands containing bromine, amine and hydroxyl functional groups. The resultant prepared compounds were utilized as bifunctional synergetic catalysts for the chemical fixation of carbon dioxide. The catalysts can efficiently catalyze epoxides and carbon dioxide under relatively mild conditions in the absence of co-catalyst and solvent. The contemporaneous presence of Lewis acid and basic centers in the framework resulted in high catalytic activity and turnover number (TON) value for the production of cyclic carbonates compared to other reported compounds indicating superiority of the synthesized catalysts. Among diverse applied bifunctional catalysts, bromine-functionalized frameworks exhibited the highest catalytic performance owing to the presence of multiple electron pairs and the great tendency to donate electron pairs.

Metal cluster/ruthenium photosensitizer/cobalt phthalocyanine synergistic photocatalytic cycloaddition of carbon dioxide and propylene oxide

The cycloaddition of CO2 and propylene oxide (PO) is of great significance to green chemistry and resource utilization. Here, two new metal clusters and four ruthenium photosensitizers were synthesized, and a series of composite catalysts were prepared by combining them with cobalt phthalocyanine. Light was introduced into the reaction system and it was found that TON increased from 550 (0 W) to 990 (200 W) at 60 °C. At 120 °C, 200 W, the TON was as high as 4616. The electron paramagnetic resonance (EPR) experiments showed that for the Cat13, electrons were generated by light irradiation. After the system was injected into PO, the photogenerated electrons quickly transferred to PO. Gibbs free energy calculations also indicate that by introducing light, the system is more likely to promote PO ring opening and exhibits excellent catalytic performance for CO2 ring addition. In addition, the recycled catalyst can still catalyze the formation of propylene carbonate from CO2 and PO.

Liquid Metal Interfacial Engineering Strategy to Synthesize All-Carbon-Linked Porous Aromatic Frameworks for the Cycloaddition of CO2 with Epoxides.

This study explores the room-temperature synthesis of porous materials and the immobilization of CO2 without the use of metals. The porous aromatic frameworks synthesized at room temperature retain the important functional group structure, and the abundance of carbon-chlorine bonds creates an excellent environment for imidazole linkage. Consequently, a catalyst conducive to the cycloaddition of carbon dioxide is obtained. Hexachloro-p-xylene is explored as the precursor, and a catalyst conducive to carbon dioxide cycloaddition is obtained. The functionalized porous aromatic frameworks (PAF-280-I/B) possess a conversion of 99.6% with a selectivity of 98.9% toward styrene carbonate (SC). The findings of this study can help mitigate the impact of greenhouse gases and enable the production of organic compounds in the circular carbonate platform, turning waste into valuable resources.

Metal–organic frameworks with Lewis acid-base sites as highly efficient catalyst for the cycloaddition of carbon dioxide

The chemical fixation of carbon dioxide (CO2) into high value-added chemicals like cyclic carbonates is an effective strategy to solve the energy and ecological issues. Metal-organic frameworks (MOFs) can efficiently catalyze the reaction due to their diverse structures and accessible active sites, herein, two novel MOFs have been successfully constructed based on bi-functional ligand 4-(2, 4-dicarboxylphenyl)-4, 2’: 6′, 4″-terpyridine) (H2dcptpy). The Fourier-transform infrared (FT-IR) spectra data indicated complete de-protonation of the H2dcptpy ligand, their structures have been refined and formulated as [Co(dcptpy)]∙DMF∙6H2O (MOF 1) with a large BET surface areas of 3.4 m2/g and [Cu(dcptpy)(H2O)2] (MOF 2). They both exhibit a three-dimensional network structure with microporosity and contain Lewis acid-base sites located on the surface of the pores. The good purity and stability of the as-synthesized samples were adequately characterized by powder X-ray diffraction (PXRD) and thermogravimetric analysis (TGA). Remarkably, a series of cycloaddition reactions of epoxides with CO2 show that MOF 1 has excellent heterogeneous catalytic activity for cyclic carbonate of epibromohydrin and butyl glycidyl ether, and almost complete conversion can be achieved even under mild conditions (1 bar CO2, 80 °C, 12 h and solvent-free). Therefore, MOF 1 has the potential to be a catalyst material for CO2 conversion.

Effect of the structure of alkylammonium halides on the outcome of carbon dioxide cycloaddition to oxiranes

Effect of the structure of alkylammonium halides on the outcome of carbon dioxide cycloaddition to oxiranes

Ionic Conjugated Microporous Polymers for Cycloaddition of Carbon Dioxide to Epoxides

AbstractAlong the development of ionic porous organic polymers, simple and efficient synthetic methods are actively pursued. Herein, the Debus–Radziszewski reaction is applied to synthesize ionic conjugated microporous polymers (iCMPs) in one step. A series of imidazolium‐linked iCMP‐X (X = 1, 2, 3) are developed for CO2 sorption and in situ conversion with epoxide into cyclic carbonates. The as‐synthesized iCMPs are characterized in detail by scanning electron microscope, solid‐state nuclear magnetic resonance, X‐ray photoelectron spectroscopy, X‐ray diffraction analysis, N2/CO2 sorption, and more. Among all synthesized iCMPs, iCMP‐1 possesses the highest specific surface area and in turn the strongest CO2 sorption capacity. Moreover, through a simple anion ion exchange reaction with halide, iCMP‐1 is transformed to iCMP‐1@Cl that embodies significant catalytic capability for converting CO2 into cyclic carbonates.

Catalysis Conversion of Carbon Dioxide and Epoxides by Tetrahydroxydiboron To Prepare Cyclic Carbonates.

A binary catalytic system comprising tetrahydroxydiboron and tetrabutylammonium iodide (TBAI) was used to catalyze the cycloaddition of carbon dioxide (CO2) with epoxides. The tetrahydroxydiboron catalyst (9 mol %), in combination with the use of TBAI (13.5 mol %) as a nucleophile, is capable of catalyzing the cycloaddition of CO2 with various terminal epoxides under room temperature and a CO2 balloon. In addition, a range of internal epoxides, including sterically hindered bicyclic epoxides and vegetable oil-based epoxides, were suitable for the catalytic system, affording a series of cyclic carbonates in moderate to high yields. The tetrahydroxydiboron/TBAI cooperative catalytic mechanism was elucidated using Fourier transform infrared spectroscopy, nuclear magnetic resonance, and electrospray ionization-high-resolution mass spectrometry. Results reveal that the tetrahydroxydiboron catalyst exhibits dual effects, activating both CO2 and epoxides; initially, it underwent the insertion of CO2 to form a boron-CO2 adduct and subsequently activated the epoxides through interaction of the B-O bond.

Gd2ZnMnO6/ZnO Ceramic Nanocomposites for the Cycloaddition of Carbon Dioxide, Amines, and Alkenes under Mild Conditions

For the first time, Gd2ZnMnO6/ZnO ceramic nanocomposites (Gd2ZnMnO6/ZnO CNCs) were fabricated by a sol-gel auto-combustion process on the basis of a reaction between Gd, Zn and Mn nitrates and saffron as a green fuel. Gd2ZnMnO6/ZnO ceramic nanocomposites were greenly formed using saffron as a novel fuel and stabilizing agent. The morphology, phase, and anatomical purity of Gd2ZnMnO6/ZnO ceramic nanocomposites could be arranged by quantity and type of fuel, temperature, and reaction period. The specimens were explored by various microscopic and spectroscopic approaches. The uncontrolled release of carbon dioxide (CO2) by industrial processes that acidify the oceans and warm the planet has prompted scientists to try different methods to capture CO2 directly from waste water sources. The fabrication of green nanocatalysts with chemical modifications to create value-added products has many benefits. Considering the morphology of Gd2ZnMnO6/ZnO, an appropriate exteriorlayer for CO2 imbibition was created in all catalystsites. Findings disclosed that Gd2ZnMnO6/ZnO positively affected the fabrication yield of 3-aryl-2-oxazolidinones by carbon dioxide, olefins, and anilines. The product was obtained with an excellent yield of 98%. This high yield was obtained in very mild conditions, such as a pressure of 2.5 atm of carbon dioxide at 80 °C for 3 h. The technique enjoyed profitable performance and forbearance of functional groups. The retrievable catalyst was recycled up to ten times for synthesis of 3-aryl-2-oxazolidinones without significant loss in its activity.

Cyclo-addition of carbon dioxide to epoxides employing hierarchical silicoaluminophosphates molecular sieves

Hierarchical silicoaluminophosphates comprising dual micro/meso pore structures have been explored, and proven to be effective, robust, and recyclable materials for the production of cyclic carbonates in the absence of co-catalyst. Upon activation at the temperature range of 80–100 °C, treated SAPOs have been examined as catalysts for the reaction. The crystalline structures of the hierarchical SAPO were checked by P-XRD. FE-SEM images confirmed the morphology and TEM measurement showed the periodicity of the framework. The BET analysis revealed the surface modification. In the cycloaddition of CO2 to epoxide (cyclohexene oxide, and styrene oxide), the hierarchical silicoaluminophosphate materials were explored where the activity of post-synthetic treated materials as catalyst was discovered to be superior. 100 % and 93 % reactant conversion were found for treated SAPO-34 and SAPO-5 catalyst, respectively.

Poly(ionic liquid)-coated hydroxy-functionalized carbon nanotube nanoarchitectures with boosted catalytic performance for carbon dioxide cycloaddition

Poly(ionic liquid)s (PILs) bearing high ionic densities are promising candidates for carbon dioxide (CO2) fixation. However, efficient and metal-free methods for boosting the catalytic efficiencies of PILs are still challenging. In this study, a novel family of poly(ionic liquid)-coated carbon nanotube nanoarchitectures (CNTs@PIL) were facilely prepared via a noncovalent and in-situ polymerization method. The effects of different carbon nanotubes (CNTs) and PILs on the structure, properties, and catalytic performance of the composite catalysts were systematically investigated. Characterizations and experimental results showed that hybridization of PIL with hydroxyl- or carboxyl-functionalized CNTs (CNT-OH, CNT-COOH) endows the composite catalyst with increased porosity, CO2 capture capacity, swelling ability and diffusion rate with respect to individual PIL, and allows the CNTs@PIL to provide H-bond donors for the synergistic activation of epoxides at the interfacial layer. Benefiting from these merits, the optimal composite catalyst (CNT-OH@PIL) delivered a super catalytic efficiency in the cycloaddition of CO2 to propylene oxide, which was over 4.5 times that of control PIL under metal- and co-catalyst free conditions. Additionally, CNT-OH@PIL showed high carbon dioxide/nitrogen (CO2/N2) adsorptive selectivity and could smoothly catalyze the cycloaddition reaction with a simulated flue gas (15% CO2 and 85% N2). Furthermore, the CNT-OH@PIL exhibited broad substrate tolerance and could be readily recycled and efficiently reused at least 12 times. Hybridization of PIL with functionalized CNTs provides a feasible approach for boosting the catalytic performance of PIL-based solid catalysts for CO2 fixation.

Efficient cycloaddition of carbon dioxide with epoxide to produce five-membered cyclic carbonates by amine-functionalized silicoaluminophosphates molecular sieves

The synthesis of functionalized microporous materials as very effective catalysts is a significant and rapidly increasing research topic with the goal for providing more efficient energy alternatives and contributing to the reduction of atmospheric CO2 levels. Carbon dioxide is a greenhouse gas that traps heat in the atmosphere, contributing to global warming and climate change. SAPO-5 and SAPO-34 molecular sieves were post-synthetically –NH2 functionalized, and the existence of –NH2 functionalities in the SAPO structure wall was demonstrated by FT-IR, CHN analysis. Powder XRD confirmed the crystalline structures of the modified SAPO-34 materials with amine functionalities. FE-SEM examined the morphology of the materials. The functionalized silicoaluminophosphate materials were investigated in the cyclo-addition of CO2 to epoxide (cyclohexene oxide and styrene oxide), where the catalytic performance of post-synthetically functionalized materials as catalyst were found to be superior. The amine group of the silicoaluminophosphates materials were essential for the activation of CO2. For treated SAPO-34, reactant conversion in cyclohexene oxide and styrene oxide was reported to be 94% and 93%, respectively. Because of the high recyclability of these materials, the catalysts are found to be both cost-effective and environmentally benign.