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A series of basic functional ionic liquids were prepared from 1, 4-diazabicyclo [2.2.2] octane (DABCO) with various halogenated hydrocarbons, then these functional ionic liquids were used as catalysts for the chemical fixation of CO2 into cyclic carbonates and the influence of the structure of the ionic liquids was investigated. The results showed that the N atom active center, types of anions and hydrogen bond of the catalyst play a key role in the cycloaddition reaction of CO2 with epoxides to cyclic carbonates. Under mild reaction conditions (T = 100 °C, 1 atm CO2), the ionic liquid [DABCO-CH2CH2CH2OH] I showed the best catalytic effect, which has notable advantages such as high catalytic activity, eco-friendly, ease of work-up and convenient reuse. [ABSTRACT FROM AUTHOR]

Porous polymer beads with grafted poly(tertiary amine) were prepared by grafting triethylenetetramine to porous crosslinked poly(methyl acrylate) beads via ester amidation reaction, followed by Eschweiler–Clarke methylation reaction using formaldehyde and formic acid to converting the primary and secondary amine groups to tertiary amines in the beads. The tertiary amine groups in the beads were protonated with hydrochloric acid, hydrobromic acid or hydriodic acid, and the protonated tertiary amine group-containing beads showed high catalytic activity and high selectivity for the formation of propylene carbonate through cycloaddition of propylene oxide with CO2, while free tertiary amine group-containing beads exhibited almost no catalytic activity. The recyclability of the catalyst was studied, and slight loss of the activity was observed after five runs. [ABSTRACT FROM AUTHOR]

In this study, imidazolium‐based multifunctional ionic polymer (IP 1–IP 3) series, co‐incorporated with phenolic hydroxyl groups as hydrogen bond donors (HBDs) and Cl− as nucleophiles, are synthesized by a facile quaternization method. The physicochemical characterizations of these IPs are systematically examined by using FTIR, XPS, BET, TGA, CO2‐TPD, SEM with elemental mapping and TEM methods. Their catalytic activities are evaluated toward the conversion of carbon dioxide (CO2) and epoxides into cyclic carbonates under solvent‐ and additive‐free environments. Apart from the synergy effect between HBDs and Cl−, it is found that the types of the spacer linking the two imidazole units in the diimidazole precursors (L1–L3) also play an important role in the catalytic activity. And IP 2, with a pyridine spacer as a Lewis base site, exhibits the best catalytic performance under solvent‐free mild conditions i. e., atmospheric pressure CO2, 80 °C, and 5 h. Notably, the catalyst demonstrates a good substrate applicability. Furthermore, IP 2 exhibited good reusability, stability, and it can be recycled for ten successive runs with stable and potential catalytic activity. This study provides an alternative route to construct IPs with efficient activity for CO2 catalytic conversion and fixation under mild‐conditions. [ABSTRACT FROM AUTHOR]

A stable iron(III) complex with the cross‐bridged cyclam 4,11‐dimethyl‐1,4,8,11‐tetraazabicyclo[6.6.2]hexadecane catalyzes the epoxidation of aromatic alkenes and the fixation of CO2 into cyclic carbonates. Best results were obtained for styrene conversion to styrene carbonate. [ABSTRACT FROM AUTHOR]

This article reviews the preparation of cyclic carbonates from alkylene oxides and CO2 catalyzed by metalloporphyrin polymers. It is found that metalloporphyrin-based porous polymers have high specific surface area, central metal of the porphyrin ring and nucleophilicity in small molecule polymerized monomers, which are the key points for efficiently catalyzing the cycloaddition reaction of epoxides and CO2 under mild conditions. However, currently synthesized metalloporphyrin polymers have some problems, such as easy pore size, unstable structure, and difficulty in adapting to large-sized epoxides. In the future, we should focus on designing and preparing dual-active site metalloporphyrin-based porous polymers with small steric hindrance, stable performance, and a large number of Lewis acid-base highly active centers, which is the direction we need to research in the future. [ABSTRACT FROM AUTHOR]

With the advantages of low raw material cost and 100% atom utilization, the synthesis of high value-added chemical product cyclic carbonates by the cycloaddition of CO2 to epoxides has become one of the most prospective approaches to achieve the industrial utilization of CO2. In the reported catalytic systems, the complexity of the catalyst synthesis process, high cost, separation difficulties, and low CO2 capture limit the catalytic efficiency and its large-scale application. In this paper, Ag nanoparticles loaded on polyethyleneimine (PEI)-modified UiO-66-NH2 (Ag/PEI@UiO-66-NH2) are successfully synthesized by in situ immersion reduction. The Ag nanoparticles and the amino groups on the surfaces of PEI@UiO-66-NH2 contribute to the adsorption of CO2 and polarization of C–O bonds in epoxides, thereby boosting the conversion capability for the CO2 cycloaddition reaction. At the amount of propylene oxide of 0.25 mol and the catalyst dosage of 1% of the substrate, the yield and selectivity of propylene carbonate are up to 99%. In addition, the stability and recyclability of Ag/PEI@UiO-66-NH2 catalyst are attained. The Ag/PEI@UiO-66-NH2 catalyst also demonstrates a wide range of activity and distinctive selectivity toward cyclo-carbonates in the cycloaddition of CO2 to epoxides. This work provides a guide to designing a highly efficient catalyst for in situ capture and high-value utilization of CO2 in industrial applications. [ABSTRACT FROM AUTHOR]

The regioselective synthesis of carbamates from bio‐derived cyclic carbonates and amines by using 1,5,7‐triazabicyclo[4.4.0]dec‐5‐ene (TBD) as an organocatalyst is reported. This methodology led to the preparation of a wide range of bio‐sourced hydroxyurethanes from furan‐, carvone‐ and limonene‐based scaffolds under solvent‐free and mild reaction conditions. Moreover, a comprehensive analysis of the process allowed us to optimize the catalyst loading with little or no impact on the process regioselectivity. [ABSTRACT FROM AUTHOR]

We introduce expanded perlite as a new, inexpensive, multi-catalytic active site and effective catalyst for the synthesis of cyclic carbonate under perfectly mild, low pressure of CO2 and solvent-free conditions. Expanded perlite efficiently catalyzes the CO2 fixation and achieves high conversion of the main products. The catalyst and products were analyzed using FTIR, X-ray diffraction, XRF, BET, Scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), and NMR. The catalyst demonstrated impressive output in the synthesis of various cyclic carbonates from epoxides. Epichlorohydrin had the best result and highest performance, transforming 97% of the cyclic carbonate in 4.5 h. This procedure has several advantages including mild reaction conditions, high yields, easy workup, short reaction time, reusability of the catalyst, and non-toxic catalyst. [ABSTRACT FROM AUTHOR]

The synthesis of bio‐derived cyclic carbonates is attracting a lot of attention as the incorporation of bio‐derived functionality into these compounds provides the opportunity to prepare previously unknown structures, whilst also improving their sustainability profiles. This study presents a facile preparation of diastereomerically pure bio‐derived cyclic carbonates displaying a range of optical rotation values. These compounds are obtained from glycidol, amino acids and CO2 in a facile two‐step approach. Initially, the diastereomerically pure amino acid functionalised epoxides are prepared through a robust Steglich esterification of enantiopure glycidol (R or S) and an amino acid (D or L). Thereafter, in a second step, cycloaddition of the epoxide with CO2 results in the retention of the initial stereochemistry of the epoxide, furnishing novel diastereomerically pure and optically active cyclic carbonate products. A DFT study has explained the basis of this observed retention of configuration for these compounds. Further, results from this DFT study also provide new mechanistic information concerning a co‐catalyst‐free cycloaddition reaction starting from glycidol when using the gallium‐catalyst, which is found to operate through metal‐ligand cooperativity. [ABSTRACT FROM AUTHOR]

The design of molecular scaffolds bearing multiple functional groups for the activation and ring‐opening of epoxides is a crucial challenge for the synthesis of efficient homogeneous and heterogeneous catalysts that are used for the cycloaddition reaction of CO2 to epoxides. Traditional approaches to prepare such multifunctional catalysts often imply multistep synthetic procedures and expensive building blocks. In this work we show that bifunctional catalysts for the cycloaddition of CO2 to epoxides bearing a Lewis acid metal and a quaternary ammonium halide group can be prepared in just two steps starting from an opportunely designed epoxide precursor by using inexpensive substrates. Such a readily accessible catalyst was applied for the cycloaddition of CO2 to a series of epoxides under atmospheric conditions generally leading to quantitative substrate conversion and high carbonate selectivities. Importantly, we also show that the epoxide‐driven concept developed for the preparation of the molecular catalyst, could be applied to prepare recyclable heterogeneous systems for the target cycloaddition reaction. [ABSTRACT FROM AUTHOR]

The cycloaddition of CO2 to epoxides to afford versatile and useful cyclic carbonate compounds is a highly investigated method for the nonreductive upcycling of CO2. One of the main focuses of the current research in this area is the discovery of readily available, sustainable, and inexpensive catalysts, and of catalytic methodologies that allow their seamless solvent-free recycling. Water, often regarded as an undesirable pollutant in the cycloaddition process, is progressively emerging as a helpful reaction component. On the one hand, it serves as an inexpensive hydrogen bond donor (HBD) to enhance the performance of ionic compounds; on the other hand, aqueous media allow the development of diverse catalytic protocols that can boost catalytic performance or ease the recycling of molecular catalysts. An overview of the advances in the use of aqueous and biphasic aqueous systems for the cycloaddition of CO2 to epoxides is provided in this work along with recommendations for possible future developments. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: A Ru(II)‐catalyzed ortho allylation reaction of N‐aryl‐7‐azaindole with readily available 2‐methylidene cyclic carbonate has been developed. This reaction is an effective pathway for synthesizing 7‐azaindole derivatives with a wide scope of substrates and high yields. In addition, the method can be extended to the allylation of other heterocyclic compounds and several cyclic carbonates, highlighting the practicality of this strategy for synthesis. [ABSTRACT FROM AUTHOR]

The anthropogenic carbon dioxide (CO2) fixation and various engineering strategies are gaining very significant attention because of the expansion of the net‐zero carbon environment in the atmosphere. Herein, we designed a sodium aluminate@γ‐alumina (NaAlO2@γ‐Al2O3) catalyst by a simple and facile precipitation and impregnation tactics. A series of different weight percentage NaAlO2@γ‐Al2O3 materials were successfully synthesized and well characterized by using advanced analytical and spectroscopic techniques such as TGA, XRD, FE‐SEM, TEM/HR‐TEM, FT‐IR, Raman, TPD, and XPS analysis. The NaAlO2@γ‐Al2O3 catalyst was employed as a competent catalyst for the CO2 fixation under atmospheric pressure reaction conditions. The catalytic activity results evidently revealed that the cycloaddition reaction successfully achieved 94% styrene oxide conversion and 93% selectivity, along with an 87% yield of the styrene carbonate at 120 °C for 6 h. Furthermore, we comprehensively examined the effect of different reaction parameters such as the effect of sodium aluminate amount, co‐catalyst amount, temperature, and time for CO2 fixation reaction. Additionally, different terminal and internal epoxides were tested under optimized reaction conditions and achieved moderate to excellent yield of the desired cyclic carbonate products. Interestingly, a plausible reaction mechanism was proposed for the styrene carbonate synthesis using NaAlO2@γ‐Al2O3 catalyst surface with the support of characterization and experimental results. Remarkably, the NaAlO2@γ‐Al2O3 catalyst could be easily recoverable and successfully recyclable up to six consecutive cycles without declining its initial catalytic activity along with stable structural and physicochemical properties. [ABSTRACT FROM AUTHOR]

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]

Rising carbon dioxide (CO2) levels in the atmosphere are recognized as a threat to atmospheric stability and life. Although this greenhouse gas is being produced on a large scale, there are solutions to reduction and indeed utilization of the gas. Many of these solutions involve costly or unstable technologies, such as air‐sensitive metal–organic frameworks (MOFs) for CO2 capture or "non‐green" systems such as amine scrubbing. Conjugated microporous polymers (CMPs) represent a simpler, cheaper, and greener solution to CO2 capture and utilization. They are often easy to synthesize at scale (a one pot reaction in many cases), chemically and thermally stable (especially in comparison with their MOF and covalent organic framework (COF) counterparts, owing to their amorphous nature), and, as a result, cheap to manufacture. Furthermore, their large surface areas, tunable porous frameworks and chemical structures mean they are reported as highly efficient CO2 capture motifs. In addition, they provide a dual pathway to utilize captured CO2 via chemical conversion or electrochemical reduction into industrially valuable products. Recent studies show that all these attractive properties can be realized in metal‐free CMPs, presenting a truly green option. The promising results in these two fields of CMP applications are reviewed and explored here. [ABSTRACT FROM AUTHOR]

This study introduces an efficient strategy for synthesizing polyhydroxyurethane-based multicomponent hydrogels with enhanced rheological properties. In a single-step process, 3D materials composed of Polymer 1 (PHU) and Polymer 2 (PVA or gelatin) were produced. Polymer 1, a crosslinked polyhydroxyurethane (PHU), grew within a colloidal solution of Polymer 2, forming an interconnected network. The synthesis of Polymer 1 utilized a Non-Isocyanate Polyurethane (NIPU) methodology based on the aminolysis of bis(cyclic carbonate) (bisCC) monomers derived from 1-thioglycerol and 1,2-dithioglycerol (monomers A and E, respectively). This method, applied for the first time in Semi-Interpenetrating Network (SIPN) formation, demonstrated exceptional orthogonality since the functional groups in Polymer 2 do not interfere with Polymer 1 formation. Optimizing PHU formation involved a 20-trial methodology, identifying influential variables such as polymer concentration, temperature, solvent (an aprotic and a protic solvent), and the organo-catalyst used [a thiourea derivative (TU) and 1,8-diazabicyclo [5.4.0]undec-7-ene (DBU)]. The highest molecular weights were achieved under near-bulk polymerization conditions using TU-protic and DBU-aprotic as catalyst–solvent combinations. Monomer E-based PHU exhibited higher M w ¯ than monomer A-based PHU (34.1 kDa and 16.4 kDa, respectively). Applying the enhanced methodology to prepare 10 multicomponent hydrogels using PVA or gelatin as the polymer scaffold revealed superior rheological properties in PVA-based hydrogels, exhibiting solid-like gel behavior. Incorporating monomer E enhanced mechanical properties and elasticity (with loss tangent values of 0.09 and 0.14). SEM images unveiled distinct microstructures, including a sponge-like pattern in certain PVA-based hydrogels when monomer A was chosen, indicating the formation of highly superporous interpenetrated materials. In summary, this innovative approach presents a versatile methodology for obtaining advanced hydrogel-based systems with potential applications in various biomedical fields. [ABSTRACT FROM AUTHOR]

The selective fixation of CO2 and epoxides into cyclic carbonates offers an atom-economical approach towards promising utilization of anthropogenic CO2 gas. This work demonstrates the development of recyclable organic–inorganic hybrid TBAI@CuO catalyst containing quaternary ammonium (TBAI) salt as active organic groups and CuO flowers as the inorganic component. Initially, CuO flowers was synthesized using a simple oxidation-precipitation method followed by immobilization of TBAI groups using impregnation method. The impregnated TBAI groups functioned as the active basic centers, whereas CuO flowers with effective surface area provided heterogeneity, Lewis acidic sites, facilitated better dispersion and strong interaction of TBAI. Resultantly, hybrid TBAI@CuO catalyst consisted of dual-active sites which played a decisive role in manipulating catalytic activity without requirement of a co-catalyst. With styrene oxide and CO2 as model substrates, the present catalyst system delivered 95% conversion and 97% selectivity towards styrene carbonate under solvent-free and milder reaction conditions when compared to other single metal oxide catalysts. The homogeneously dispersed TBAI groups in strong interaction with CuO flowers provided simultaneous access to both Lewis acidic as well as basic sites and hence resulted in superior catalytic activity. Meanwhile, hybrid TBAI@CuO catalyst showed catalytic adequacy for various terminal and internal epoxides. This catalytic system also presented good reusability without prominent loss in activity and no leaching of active TBAI groups. Based on characterization results, a plausible reaction mechanism was predicted to support the cycloaddition reaction with hybrid TBAI@CuO catalyst. It was proposed that inorganic Lewis acidic CuO activated the epoxide whereas the immobilized TBAI groups activated the inert CO2 molecule and stabilized the epoxide after ring opening. Therefore, the CuO flowers acting in concert with the immobilized TBAI groups showed exceptional acid–base cooperativity and provided high selectivity towards cyclic carbonates. The hybrid TBAI@CuO catalyst in this effort bridges the gap between homogeneous and heterogeneous catalysis for sustainable transformation of CO2 and epoxides to cyclic carbonates under solvent-free and comparatively mild reaction conditions [ABSTRACT FROM AUTHOR]

Polyoxometalates can be tuned for specific catalytic property by substituting transition metal ions. We report the synthesis of hybrid materials of Cu2+, Co2+ and Ni2+ substituted phosphotungstates and poly(diallyldimethylammonium) chloride polymer (PDDA) for CO2 fixation. The in situ generated transition metal substituted polyoxometalates (TMS-POMs) are analyzed by FTIR, powder XRD, 31P NMR and SEM techniques. The hybrid TMS-POM materials are found to be good catalysts for converting epoxides to cyclic carbonates. Among these, PDDA-PWCo is the most efficient catalyst for cycloaddition of CO2 under solvent-free conditions at room temperature in shortest reaction time. Only 0.2 mol% of PDDA-PWCo is enough to deliver 100% conversion and selectivity to cyclic carbonates. This catalytic approach is employed for conversion of other cyclic, acyclic, and aromatic epoxides without using column purifications. Overall, the method of obtaining cyclic carbonates under green conditions using TMS-POMs-PDDA hybrid materials appears suitable for industrial applications. [ABSTRACT FROM AUTHOR]

Chloromethylation of cross-linked styrene-divinylbenzene beads with subsequent quaternization with amines was carried out. The resulting anion exchangers were tested as catalysts for the addition of CO2 to oxiranes and as sorbents for the separation of Zr, Nb, Hf, Ta, and Th salts from nitric acid solutions. The anion exchanger can be used in six catalytic cycles for the reaction of CO2 addition to oxiranes, which led to cyclic carbonates in quantitative yields. [ABSTRACT FROM AUTHOR]

Nowadays there is an urgent need for mitigating CO2 emissions through clean energy and the development of new carbon capture and utilization (CCU) technologies. Among others, the use of bifunctional ionic liquids (ILs) addressed simultaneously CO2 capture and conversion steps, having applied successfully to the propylene carbonate production case. In this work, a systematic evaluation of all representative cyclic carbonate literature was made, covering ethylene, propylene, butylene, hexylene, cyclohexene, and styrene cyclic carbonates, in order to guide the product role within the integrated CCU (ICCU) concept. The multiscale strategy combining molecular simulation (DFT -Density Functional Theory-, COSMO -COnductor-like Screening MOdel-), process simulation (COSMO/Aspen methodology), and life cycle assessment (LCA) was used to set up, simulate and evaluate the processes. ICCU configuration is the best approach when compared with sequential configuration for energy consumption analysis (reduction of 28, 28, 22, 11 and 6 %, respectively, for ethylene, propylene, butylene, hexylene, and cyclohexene cases) and CO2 emissions associated (reduction of 38, 40, 31 and 14 %, respectively, for ethylene, propylene, butylene, and hexylene cases). The main variable of the results is the boiling point of the cyclic carbonate since heavy products impose technical limitations and even discard ICCU alternative. The ICCU concept works since all cyclic carbonates’ reaction enthalpies are higher than that of the IL-CO2 one, which reduces heating requirements. Finally, energy demand can be slightly further reduced, partially recycling the cyclic carbonate to the capture unit.

The conversion of CO2 with epoxides into the corresponding cyclic carbonates represents a green approach to transform a waste into value-added products. To promote this conversion, a catalyst in needed. This study presents the synthesis of two cross-linked materials composed of magnesium phthalocyanine and imidazolium bromide moieties: MgPc-BIBI-Br and MgPc-SIBI-Br. Magnesium phthalocyanines are cost-effective and versatile catalysts, synthesized in high yield from low-cost precursors and can be easily modified for specific needs. Imidazolium bromide groups play a crucial role as well, acting as a nucleophile source essential to promote the ring-opening process of the epoxide. The materials have been extensively characterized through analytical and spectroscopic techniques and tested as catalysts in the conversion of epichlorohydrin into 4-chloromethyl-1,3-dioxalan-2-one. They both achieved excellent catalytic performance (maximal TON values of 3070 for MgPc-SIBI-Br and 1903 for MgPc-BIBI-Br) and recyclability (both recyclable at least for 4 cycles). The reported results represent an improvement if compared to similar materials already reported in the literature in which the addition of external nucleophilic species (e.g. TBAB, BMIM-Br, etc.) is needed. To the best of our knowledge, this work is the first example in which imidazolium bromide and magnesium phthalocyanine moieties are combined in bifunctional polymeric materials that convert CO2 into cyclic carbonates via heterogeneous catalysis.

This study introduces a straightforward synthesis method for producing a hybrid material composed of halloysite and kojic acid, which catalyzes carbon dioxide (CO2) conversion processes. Kojic acid, derived from malted rice fermentation, exhibits inherent chelating properties that facilitate the introduction of copper ions onto the material’s surface. Copper ions, an economically viable alternative to noble metals, catalyze CO2 conversion reactions effectively. The hybrid catalyst was evaluated for two distinct CO2 conversion pathways: photocatalytic methane production under simulated sunlight and CO2 fixation into cyclic carbonates via epoxide reactions. The hybrid material demonstrates remarkable catalytic activity under mild conditions, achieving high conversion efficiencies at 45 °C for methane production and 70 °C for carbonate fixation at atmospheric pressure. Conversion of 31 % and 89 % were achieved for the photocatalytic CO2 reduction and the carbonate fixation, respectively. FT-IR spectra confirmed the functionalization of the material. Additionally, its organic/inorganic hybrid nature is complemented by excellent thermal stability, as studied by TGA. It enables repeated utilization, maintaining a 25 % catalytic activity for methane production and 70 % for carbonate fixation after the fourth reuse. This research highlights the potential of using naturally derived materials for sustainable CO2 mitigation.

A catalytic domino, three‐component reaction has been developed for the transformation of carbon dioxide into functionalized six‐membered cyclic carbonates. The catalytic process combines an initial carboxylative cyclization of β‐epoxy alcohols followed by an oxa‐Michael reaction affording an unparalleled scope of heterocyclic structures. The wide range of functional groups, including free‐alcohols, empowers the access to a range of products including C11‐oxo‐based bicyclic heterocycles. The versatility of these functionalized carbonates is further complemented by a series of synthetic diversifications. Control experiments are consistent with the first step of this domino process being promoted by a binary Lewis acid/base catalyst, while the second stage only requires catalytic base. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: Polyhydroxyurethanes (PHUs) have received considerable attention in the last decade as potential alternatives to traditional phosgene‐based polyurethanes (PUs). The development of suitable 5CC (five membered‐ring cyclic carbonate) precursors bearing multiple carbonate moieties (multi‐5CCs) is a key requisite for preparing PHUs by polyaddition reaction with bis‐ or polyamines. Producing sustainable PHUs from CO2‐based five‐membered cyclic carbonates (5CCs) obtained from biobased epoxides is a valuable strategy to bridge CO2 utilization and the upcycling of renewable substrates. In this context, while many multi‐5CC monomers reported in the literature are oil‐based, recent efforts have led to the development of a large variety of multifunctional 5CCs that are produced by the combination of CO2 and renewable resources such as fatty acids and vegetable oils, lignin, terpenes, and sugars. In this work, recent crucial advances (2019—2023) on PHUs prepared from bis‐ and multi‐5CCs produced from CO2 and (partially/potentially) biobased substrates are reviewed with respect to their synthesis, thermal and mechanical properties, and their recent, emerging applications. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: Polyhydroxyurethanes (PHUs) have received considerable attention in the last decade as potential alternatives to traditional phosgene‐based polyurethanes (PUs). The development of suitable 5CC (five membered‐ring cyclic carbonate) precursors bearing multiple carbonate moieties (multi‐5CCs) is a key requisite for preparing PHUs by polyaddition reaction with bis‐ or polyamines. Producing sustainable PHUs from CO2‐based five‐membered cyclic carbonates (5CCs) obtained from biobased epoxides is a valuable strategy to bridge CO2 utilization and the upcycling of renewable substrates. In this context, while many multi‐5CC monomers reported in the literature are oil‐based, recent efforts have led to the development of a large variety of multifunctional 5CCs that are produced by the combination of CO2 and renewable resources such as fatty acids and vegetable oils, lignin, terpenes, and sugars. In this work, recent crucial advances (2019—2023) on PHUs prepared from bis‐ and multi‐5CCs produced from CO2 and (partially/potentially) biobased substrates are reviewed with respect to their synthesis, thermal and mechanical properties, and their recent, emerging applications. [ABSTRACT FROM AUTHOR]

The fixation of CO2 into valuable chemicals under mild conditions is of great importance. Here, we reported an efficient and mild method for the cycloaddition of CO2 to cyclic carbonates. Iodized salt of DBU was used as hydrogen-bonding acceptor, 4-methoxyphenol was employed as hydrogen-bonding donor, and deep eutectic solvent was synthesized and characterized by NMR, FI-IR and thermogravimetric analysis. Optimization of the reaction conditions catalyzed by the deep eutectic solvent was performed, a series of epoxides have been converted to the corresponding products with excellent yields under the optimized conditions. The reaction kinetics for the synthesis of cyclic carbonates was investigated, in addition, excellent recovery performance of the catalyst was obtained after recycling for 5 times. Comparing with the literature reported, the method was much milder and efficient simultaneously. This work provides a promising way to the fixation of CO2. [ABSTRACT FROM AUTHOR]

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Comprehensive Summary: Carbon dioxide can be converted into functional heterocycles known as cyclic carbonates, whose recent reactivity has been expanded towards the formation of tailor‐made engineering polymers. This minireview gives an overview of the most topical developments in this area with a special focus on the synthetic methods employed to prepare these CO2 based synthons. In addition, their application potential in the area of polymer science using a variety of polymerization techniques is discussed that have in common the ring‐opening of the carbonate monomers. Future perspectives are provided that provide impetus for the scientific communities aligning research to the use of sustainable processes for polymers from recyclable carbon sources such as CO2. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: Carbon dioxide can be converted into functional heterocycles known as cyclic carbonates, whose recent reactivity has been expanded towards the formation of tailor‐made engineering polymers. This minireview gives an overview of the most topical developments in this area with a special focus on the synthetic methods employed to prepare these CO2 based synthons. In addition, their application potential in the area of polymer science using a variety of polymerization techniques is discussed that have in common the ring‐opening of the carbonate monomers. Future perspectives are provided that provide impetus for the scientific communities aligning research to the use of sustainable processes for polymers from recyclable carbon sources such as CO2. [ABSTRACT FROM AUTHOR]

The effective chemical valorization of CO2 by means of its conversion into valuable products is now more than ever a topic of considerable interest. It is on that basis that herein we have chosen the conversion of CO2 and epoxides to cyclic carbonates as a convenient route to achieve this goal. A new bifunctional (Lewis acid/nucleophile) heterogeneous material, TSP‐AlCl‐PhospBr, was designed in order to guarantee a close proximity between the two active sites that can cooperate to the activation and opening of the epoxide ring. The prepared copolymer has been extensively characterized using various spectroscopic and analytical techniques. As a heterogeneous catalyst, it enables efficient chemical conversion of CO2 and epoxides, even at low temperatures, down to 30 °C, without the use of solvents. In particular, the catalyst demonstrates high turnover numbers (TON) and frequency values (TOF). Recyclability studies on TSP‐AlCl‐PhospBr have shown its stability and reusability for consecutive cycles without the need of reactivation procedures. [ABSTRACT FROM AUTHOR]

The conversion of atmospheric carbon dioxide (CO2) gas mixtures and epoxides to cyclic carbonates is an environmentally beneficial execution strategy, which is a useful platform chemical. However, this reaction is overly dependent on harsh reaction conditions including temperature and/or CO2 pressure in the traditional conversion process. We report a series of facilely prepared functionalized ionic liquids (ILs) for the one-pot synthesis of styrene carbonate (SC) from pure/diluted CO2 with styrene oxide (SO). Which achieved a yield up to 99% under atmospheric CO2 conditions. In addition, with the assistance of a small amount of catalyst, the product yield remained at 99% under diluted CO2 conditions. This result demonstrates that functionalized ILs could effectively catalyze the cycloaddition reaction of low-pressure CO2 without any co-catalysts such as metals, organic solvents, and active additives. The density functional theory (DFT) calculations combined with experimental results revealed that the highest catalytic ability of Cat.2 was ascribed to the synergic catalysis between positive charge delocalized cations and Br− anions to efficiently activate the substrates. Furthermore, the best ILs catalyst can be reused five times without significant reduction in catalytic activity, which shows its great potential for chemical conversion of atmospheric CO2. [ABSTRACT FROM AUTHOR]

One‐pot tandem synthesis of cyclic carbonates from olefins and CO2 is becoming one of the most potential strategies to fix CO2 and yield high value chemicals. However, this reaction route is in need of high performing catalysts with multifunctionalized catalytic sites in single material which is still a big challenge in one‐pot community. In this term, we combined dimension reduction and surface modification strategies to fabricate a MOF/metal complex composite, that is, Zr‐BTB/PA‐Co. In this composite, the increased Lewis base sites is capable of boosting the adsorption and activation of CO2, which further acted as nucleophilic groups to activate epoxides, while the 2D matrix offered accessible intrinsic Lewis acid sites. These advantages synergistically led to superior catalytic performance of Zr‐BTB/PA‐Co for catalyzing one‐pot reaction of olefins and CO2 under mild conditions (80°C, 1 bar, 12 h and co‐catalyst/solvent free), and even impressive catalytic activity when using CO2 directly from air. [ABSTRACT FROM AUTHOR]

In this work, two ionic liquids (ILs) immobilized metal‐organic frameworks (MOFs), Fe‐MIL‐101‐3N(BuBr) and Fe‐MIL‐101‐N(Bnme2)Br, were obtained by modifying amino groups in Fe‐MIL‐101‐NH2 with bromobutane and quaternary ammonium salt. The ionic liquid immobilized MOFs have Lewis acid sites (Fe3+) and nucleophilic sites (Br−), which can synergistically catalyze the cycloaddition reaction of CO2 and epoxides. Various cyclic carbonate derivatives were obtained in excellent yields under the optimal conditions. Additionally, we found that Fe‐MIL‐101‐N(Bnme2)Br exhibited the highest catalytic activity and it can be easily recovered and reused for at least 5 times without loss of catalytic activity. Our method of preparing bifunctional catalysts provides a new approach to design catalysts for the chemical conversion of CO2. [ABSTRACT FROM AUTHOR]

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). [ABSTRACT FROM AUTHOR]

Undecylenic acid, glycerol, and CO2 were used as building blocks for obtaining a fully bio‐based carbonated monomer, useful for polyurethanes. The functionality of the monomer was close to 3 cyclic carbonates/mol, located in terminal positions. In a first stage, a synthetic triglyceride was obtained with 99% selectivity by esterification of glycerol and undecylenic acid at 160°C. The triglyceride was then epoxidized using H2O2 and Amberlyst 15 or Amberlite IR‐120 acidic exchange resins at 57°C. The selectivity to epoxide was kept constant at 98% using Amberlite IR‐120. Terminal cyclic carbonates were then inserted through epoxide moieties under mild conditions by the chemical fixation of CO2 at 80°C and 6 MPa in 6 h. A complete conversion was obtained in 6 h reaction while the selectivity to carbonate groups was near to 99% during all the reaction time. An elastomeric polyhydroxyurethane was obtained by aminolysis of the carbonated monomer with ethylenediamine at 70°C, affording a Young's modulus of 22.6 MPa and Tg of −15.2°C. The material showed a good thermal stability below 240°C. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

The novelty of this work consists of synthesizing and exploiting a heterogeneous catalyst containing ammonium chloride as part of the polymeric sponge sites for CO2 capture. To this aim, the polymerization of 2-acryloyl(oxyethyl)trimethylammonium chloride was performed in cryo-condition, in the presence of a crosslinking agent, obtaining a lightweight macroporous freestanding material. Its efficiency in converting aromatic and aliphatic epoxides to the corresponding carbonates was successfully proved by using proton Nuclear Magnetic Resonance (1H NMR). Remarkably, the conversion of styrene oxide (SO) to styrene carbonate (SC) reached a yield of 99 % after 24 h of reaction. The calculated yield versus the aliphatic cyclohexene oxide is 71 %. Similar results were obtained by substituting the resin counter anion with Br−, although the conversion kinetic was slower than the chloride. It is worth noticing that reactions took place in the mixture without adding the tetrabutylammonium bromide (TBAB), typically used as a co-catalyst to convert epoxides into carbonates. The recyclability of the as-prepared catalyst was evaluated for four reaction cycles, evidencing stable properties without significant depletion of CO2 capture efficiency. Most importantly, the post-cleaning of the catalytic sponge is not required to be reused. Finally, the green chemistry metrics applied to the process demonstrated that our approach significantly mitigates risks and reduces environmental impact, thus elevating the overall cleanliness of our proof of concept.

The cycloaddition reaction of CO2 with epoxides such as limonene epoxide (LE) to form cyclic carbonates is considered a promising alternative for reducing CO2 emissions. In this work, CO2 fixation on LE to produce cyclic carbonates was carried out over Zn/SBA-15 with tetrabutylammonium bromide (TBAB) as co-catalyst and over NH3X-Zn/SBA-15 (X= Cl, Br, or I) catalysts. The catalysts were characterized by FT-IR, XRD, N2 adsorption–desorption isotherms, TEM, NH3-TPD, XPS, TGA and Py-FTIR. The Zn/SBA-15 support mainly presents Lewis’s acid sites of medium acidity; the surface area was 512 m2/g and 378 m2/g and the pore size were 9 nm and 7.2 nm, for Zn/SBA-15 and NH3Cl-Zn/SBA-15, respectively. The functionalization of Zn/SBA-15 was verified by FTIR, UV-vis, and XPS analysis. It was found that when Zn/SBA-15 was used as catalyst that reaction time had a significative effect on LE conversion and in the case of limonene carbonate selectivity, co-catalyst concentration variation had the main effect. Zn/SBA-15 catalyst can be reused up to 5 times without significant changes neither in conversion nor in limonene carbonate selectivity. The best LE conversion and limonene carbonate selectivity was 33% and 93%, respectively (1 M LE, 200 mg Zn/SBA-15, 7% TBAB; 30 bar, 18 h, 700 rpm and 20 mL diethyl carbonate). The reported catalytic system is a promising system for obtaining limonene carbonate using a heterogeneous catalyst.

Abstract Rising carbon dioxide (CO2) levels in the atmosphere are recognized as a threat to atmospheric stability and life. Although this greenhouse gas is being produced on a large scale, there are solutions to reduction and indeed utilization of the gas. Many of these solutions involve costly or unstable technologies, such as air‐sensitive metal–organic frameworks (MOFs) for CO2 capture or “non‐green” systems such as amine scrubbing. Conjugated microporous polymers (CMPs) represent a simpler, cheaper, and greener solution to CO2 capture and utilization. They are often easy to synthesize at scale (a one pot reaction in many cases), chemically and thermally stable (especially in comparison with their MOF and covalent organic framework (COF) counterparts, owing to their amorphous nature), and, as a result, cheap to manufacture. Furthermore, their large surface areas, tunable porous frameworks and chemical structures mean they are reported as highly efficient CO2 capture motifs. In addition, they provide a dual pathway to utilize captured CO2 via chemical conversion or electrochemical reduction into industrially valuable products. Recent studies show that all these attractive properties can be realized in metal‐free CMPs, presenting a truly green option. The promising results in these two fields of CMP applications are reviewed and explored here.

We report on the metal-free and rapid catalytic conversion of carbon dioxide into cyclic carbonates under solventless conditions utilizing novel bifunctional fluoroalcohol-based ionic liquids (FBILs) as catalsyts. In the presence of 2.5 mol% 4-(1,1,1,3,3,3-hexafluoro-2-hydroxyisopropyl) phenyl trimethylammonium iodide (FBIL-1), under 0.1 MPa and 90 °C, excellent yield of propylene carbonate(>95%) was achieved in 1 h, which significantly shortens the reaction time, compared with the conventional catalysts. DFT calculations reveal that FBILs with fluorine-substituted hydroxyl groups exhibit stronger hydrogen bonding with epoxides compared to ILs lacking fluorine substitutions. The hydrogen bond length for ILF/PO is 1.658 Å, shorter than that for IL/PO (1.813 Å). This characteristic contributes to reducing the activation energy for the ring-opening reaction of epoxides. In the ILF/PO system, the reaction barrier is 88.72 kJ·mol−1, lower than the 101.46 kJ·mol−1 barrier for IL/PO, allowing the former to more rapidly facilitate the fixation of carbon dioxide into cyclic carbonates. Besides high catalytic efficiency, these FBILs have the characteristics of a facile synthesis route and easy post-reaction recovery.

Cyclic carbonates have received significant interests for uses as reagents, solvents, and monomers. The coupling reaction of epoxides with carbon dioxide (CO2) to produce cyclic carbonate is an attractive route which can significantly reduce greenhouse gas emissions and environmental hazards. Herein, a series of five indium chloride complexes supported by inden Schiff‐base ligands were reported along with four X‐ray crystal structures. The constrained five‐membered rings were added to the ligands to enhance the coordination of epoxides to the In metal. From the catalyst screening, In inden complex having tert‐butyl substituents and propylene backbone in combination with tetrabutylammonium bromide (TBAB) exhibited the highest catalytic activity (TON up to 1017) for propylene oxide/CO2 coupling reaction with >99 % selectivity for cyclic carbonate under solvent‐free conditions. In addition, the catalyst was shown to be active at atmospheric pressure of CO2 at room temperature. The catalyst system can be applied to various internal and terminal epoxide substrates to exclusively produce the corresponding cyclic carbonates. [ABSTRACT FROM AUTHOR]

Porous polymeric frameworks have received great interest over the past few years because of their nonstop growth as crystalline porous polymeric materials connected through covalent bonds and versatile utilities in diverse fields. The production of high-value organic compounds via sustainable and environment-friendly methods is an uphill struggle for researchers. The elegant strategy of using carbon dioxide as a C1 building block is an intriguing platform owing to its non-toxicity, easy accessibility, natural abundance, recyclability, non-flammability, and cheapness. Additionally, CO2 levels are regarded as the main contributor to the greenhouse effect (the most abundant greenhouse gas across the globe) and the aforementioned strategy needs to mitigate CO2 emissions. This present study describes the synthesis of silver nanoparticles (AgNPs) embedded in a porous polymeric framework, a reusable heterogeneous catalyst (recyclable over 5 times), TpMA (MC)@Ag. The synthesized catalyst is characterized by using FT-IR, PXRD, XPS, FE-SEM, TEM, EDAX, TGA DTA, and N2 sorption studies. Additionally, the catalysts can be easily recycled to generate the desired α-alkylidene cyclic carbonates and oxazolidinone compounds under solvent-free conditions. This research demonstrates the potential of nanoporous 2D porous polymeric framework-based materials in the area of catalysis, specially, in CO2 capture and chemical fixation. These findings offer a promising approach for the chemical fixation of CO2 into α-alkylidene cyclic carbonates and oxazolidinones from propargylic alcohols utilizing AgNPs embedded in a 2D catalyst, which functions as a potential heterogeneous catalyst under mild conditions (e.g., solvent-free approach). [ABSTRACT FROM AUTHOR]

The effect of structure of alkylammonium halides on the outcome of cycloaddition of carbon dioxide to oxiranes was studied. The conversion of epichlorohydrin to chloromethylethylene carbonate depends nonlinearly on the length of the hydrocarbon chain in the alkylammonium halide catalyst. Tetraethylammonium and benzyltriethylammonium were the most effective cations in the catalyst used. Acetone was the solvent of choice for this reaction under the studied conditions. [ABSTRACT FROM AUTHOR]

In this study, we report a successful strategy for the generation of palladium nanoparticles on porous P-doped carbon spheres with a high surface area. The synthesized Pd/P-CS was used in the CO2 fixation reaction with various epoxides under solvent-free conditions. The prepared Pd0/P-CS nanocatalyst was affirmed by different analysis, including TEM, FE-SEM, EDS, BET, FT-IR, XRD, and ICP-OES. The aforesaid nanocatalyst with a unique porous structure was an outstanding catalytic performance on different substrates toward produce of cyclic carbonates under solvent-free condition with high yields of final products. The catalytic activity of Pd0/P-Cs could be maintained efficiently after recycling up to five consecutive runs under the optimized reaction conditions. [ABSTRACT FROM AUTHOR]

Polymeric foams are widely used in many industrial applications due to their light weight and superior thermal, mechanical, and optical properties. Currently, increasing research efforts is being directed towards the development of greener foam formulations that circumvent the use of isocyanates/blowing agents that are commonly used in the production of foam materials. Here, a straightforward, one‐pot method is presented to prepare self‐blown polycarbonate (PC) foams by exploiting the (decarboxylative) S‐alkylation reaction for in situ generation of the blowing agent (CO2). The concomitant formation of a reactive alcohol intermediate promotes a cascade ring‐opening polymerization of the cyclic carbonates to yield a cross‐linked polymer network. It is shown that these hydroxyl‐functionalized polycarbonate‐based foams can be easily recycled into films through thermal compression molding. Furthermore, it is demonstrated that complete hydrolytic degradation of the foams is possible, thus offering the potential for zero‐waste materials. This straightforward and versatile process broadens the scope of isocyanate‐free, self‐foaming materials, opening a new pathway for next‐generation environmentally friendly foams. [ABSTRACT FROM AUTHOR]

The biocatalytic kinetic resolution of cyclic carbonates derived from glycerol is reported. A selection of 26 esterases and lipases was tested for the asymmetric hydrolysis of the model substrate (epichlorohydrin carbonate) in aqueous medium. Among them, Pig Liver Esterase and Novozym® 435 showed the best selectivity with E=38 and 49, respectively. Both enzymes were employed for the conversion of 12 glycerol derivatives under optimized conditions. The resolution of halogenated carbonates afforded the unconverted enantiomer in up to >99 : 1 er. Furthermore, Novozym® 435 was successfully recycled 10 times without significant loss of activity. Upscaling and isolation of the chiral carbonate was also demonstrated. Subsequent conversion of this chiral building block allowed the direct one‐pot synthesis of (S)‐Guaifenesin, (S)‐Mephenesin and (S)‐Chlorphenesin in up to 89 % yield and 94 : 6 er. [ABSTRACT FROM AUTHOR]