Cycloaddition Of Carbon Dioxide Research Articles

Self‐Assembled Metalloporphyrins–Magnesium Phosphate Hybrid Spheres as Efficient Catalysts for Cycloaddition of Carbon Dioxide

AbstractDue to the unique microstructure and superior catalytic properties, organic‐inorganic hybrid materials attract extensive attention. Herein, we report a facile coprecipitation method for the fabrication of metalloporphyrin–metal phosphate salt hybrid spheres, and the cycloaddition of carbon dioxide with epoxides is employed as probe reaction to evaluate the catalytic performance of our as‐synthesized catalysts. The hybrid spheres composed of meso‐tetra‐(4‐N‐pyridyl) zinc porphyrin (ZnTPyP)–magnesium phosphate exhibited superior catalytic performance, and the conversion was much higher than that of individual ZnTPyP and magnesium phosphate, probably because of the acid‐base synergistic effect. Meanwhile, the spheres showed excellent stability during the circulation experiments as well as compatibility with a wide scope of substrates. This work provides a valuable approach for the preparation of novel and efficient heterogeneous catalytic composites.

2-Methylimidazole Modified Co-BTC MOF as an Efficient Catalyst for Chemical Fixation of Carbon Dioxide

[(CH3)2NH2][Co3(BTC)(HCOO)4(H2O)]·H2O (Co-BTC) was synthesized under solvothermal conditions, further used as the precursor for the synthesis of 2-methylimidazole modified Co-BTC (2MeIm@Co-BTC-x). The characteristics of 2MeIm@Co-BTC-x were systematically characterized by various technologies including XRD, FESEM, FT-IR, XPS, N2-adsorption, TG-DTG and CO2/NH3-TPD. It was found that except for the crystal faces (0 1 1) and (− 1 0 2) corresponding to ZIF-67 and Co-BTC, a new crystal phase appeared at 12.22o for the modified Co-BTC, which may be attributed to the coordination between 2MeIm and unsaturated Co ions of Co-BTC. Interestingly, a new structure of hexagonal prisms together with hierarchical porous were also formed for the modified Co-BTC. Besides, when this composite was explored as a heterogeneous catalyst for catalytic conversion of carbon dioxide with epichlorohydrin (ECH) as probe, an obvious enhancement in catalytic activity was obtained compared with the fresh Co-BTC, suggesting that 2MeIm ligands within the modified Co-BTC played a great role on the coupling process. Furthermore, 97.21% of ECH conversion and 98.79% of chloropropene carbonate selectivity were gained over 2MeIm@Co-BTC-1.0 under optimal conditions (3.0 MPa, 90 °C, 5 h, 0.75 wt% catalyst of ECH). Additionally, only a slight decrease in catalytic activity was found after the optimal sample was reused three times. Finally, a mechanism for interpreting the coupling process of carbon dioxide cycloaddition with epoxide was proposed. One-pot catalytic conversion of CO2 into cyclic carbonate over 2-methylimidazole modified Co-BTC

Construction of a porous Cu(II)-coordinated framework for the catalytic properties of cycloaddition of carbon dioxide to epoxides

A new porous material {[Cu2(acc)1.5(phen)2]}n (denoted as 1) was synthesized by the self-assembly of Cu(II) ions with two mixed ligands, 4-carboxycinnamic acid (H2acc) and phenanthroline (phen), and further structurally characterized. The single crystal X-ray diffraction indicated that 1 contained a two-dimensional network with bimetallic Cu(II) clusters. The magnetic susceptibility experiments showed the antiferromagnetic interactions between the two Cu(II) cores. Additionally, 1 could serve as an effective heterogeneous catalyst for cyclic carbonates reactions between epoxides and CO2, achieving a high yield of above 99% in a mild condition.

High yield cycloaddition of carbon dioxide to epoxides catalyzed by metal–organic frameworks

A series of metal–organic frameworks (MOFs) based on trimesic acid (also knows benzene tricarboxylic acid [btc]) have been synthesized by a solvothermal procedure which exhibit excellent catalytic fixation of CO2. Cycloaddition of CO2 to epoxides to produce cyclic carbonates is quite promising. The chemical fixation of CO2 reported here is solvent free and carried out under moderately mild conditions. All the MOFs [Zn-btc (1), Co-btc (2), Ni-btc (3), and Cu-btc (4)] were synthesized under same experimental conditions yet possess different structural and catalytic properties. All the catalysts follow first-order kinetics, and Zn-btc (1) proved to be the most catalytically active catalyst among all, with ∼100% yield with a total turnover number of 18,845 mol−1 and an initial turnover frequency (hour−1) of 946 with respect to the cyclic carbonate. All MOFs (1–4) show almost 100% conversion in these reactions. The same reaction using other metal (Co, Ni, Cu)-btc compounds has also resulted in products with more than 94% yield, creating an extra impact on the importance of the work.

Synthesis, characterization and catalytic activity of ionic liquid mimic halides modified MCM-41 for solvent free synthesis of phenyl glycidyl carbonate

The different type of halide modified mesoporous silica catalysts were prepared via post-grafting technique using meso-silica derived from rich husk by simple sol-gel method. The physico chemical characterizations of as prepared catalysts were characterized using FT-IR, N2-sorption-desorption study, 13C CP/MAS NMR and SEM techniques. FT-IR and 13C CP/MAS NMR revealed the effective anchorage of imidazole and 1,2-dihaloethane on the MCM-41. SEM analysis images shows the comprise worm-like agglomerated structure which was similar to MCM-41. The catalysts were then used in cycloaddition of carbon dioxide and phenyl glycidyl ether under solvent free or less conditions. Among the prepared catalyst, Br-immobilized MCM-41 shows higher catalytic activity (96.7%) under ambient reaction by adopting following conditions such as 100 °C, 20 bar initial CO2 pressure, 300 mg catalyst mass and 3 h. The conversion of phenyl glycidyl ether using ImI-MCM-41 and ImCl-MCM-41 are 77.3% and 26.4% respectively. The catalytic results are confirmed that the synergistic effect owing to the stronger nucleophilicity of bromide− and amine could be promoted the reaction smoothly. The catalyst was recovered and reused for four times without a significant decrease in activity or product selectivity. A possible site for CO2 activation by ImBr-MCM-41 catalyst could be the potential ionic liquid mimic's halide immobilized MCM-41 like material for efficient conversion of the substrates such as phenyl glycidyl ether and Epoxy hexane for cycloaddition reactions have been demonstrated.

Chemical fixation of carbon dioxide catalyzed via cobalt (III) ONO pincer ligated complexes

Chemical insertion of carbon dioxide into epoxides under ambient conditions has become one of the most important methods for the construction of cyclic organic carbonates. Various active salen, salophen, and phenolate ligand based complexes have been reported for the synthesis of cyclic organic carbonates. Here we demonstrate a series of ONO pincer type cobalt (III) complexes as efficient catalysts for the cycloaddition of carbon dioxide to epoxides in neat conditions at atmospheric pressure with and without co-catalyst. A turnover number of up to 200,000 under atmospheric pressure is achieved. Moreover, the in situ generated complex shows high activity and the catalyst can be reused for at least 11 cycles without any decline in catalytic performance.

Effect of ionic liquids clusters microenvironment on cycloaddition reaction of carbon dioxide

The mechanism for the cycloaddition of carbon dioxide and epoxides catalyzed by ionic liquids has been elucidated in lots of theoretical literature. It is well known that the calculated barrier height could not be compared with the activation energy. However, it is expected that the sequence of activity estimated by barrier height could be consistent with the experimental result. Actually, the calculated results are not accurate enough to be reliable. One of possible reasons is attributed to the improper treatment for the solvent effect. The solvent effect induced by ionic liquids is not carefully considered or neglected at all in most of previous theoretical studies. In this work, ionic liquids are really included in the catalytic system to consider the solvent effect by the ONIOM method along with the molecular dynamics simulations. When the solvent effect is considered, the theoretical reliability is greatly improved. More important, this model is suitable not only for non-protic ionic liquids but also for protic ones and not only for imidazolium ionic liquids but also for pyrazolium ionic liquids. The solvent effect aroused by epoxides is also considered by the same model.

A Mn(II)-porphyrin based metal-organic framework (MOF) for visible-light-assisted cycloaddition of carbon dioxide with epoxides

Abstract The construction of a microporous 3D supramolecular Mn(II)-porphyrin metal-organic framework, [{Mn(TCPP)0.5(H2O)2}.2H2O]n (MOF1) (where, TCPP = 5,10,15,20-tetrakis(4-carboxyphenyl)porphyrin) exhibiting unprecedented visible-light-assisted cycloaddition of CO2 with epoxides to generate cyclic carbonates at mild conditions of room temperature (RT) and 1 bar CO2 has been reported. Single crystal structure determination reveals that MOF1 has an interesting microporous 2D network structure with 1D channels of dimension, 6.32 × 11.88 A2 along the crystallographic c-axis. The 2D networks are further interacting through O-H⋯O hydrogen bonding interaction between carboxylate oxygen and hydrogen of water molecules coordinated to Mn(II) center forming a 3D supramolecular framework. Gas adsorption studies revealed selective adsorption property of MOF1 for CO2 (selectivity constants for CO2/H2 = 39, CO2/N2 = 19, CO2/Ar = 21) with the isosteric heat of adsorption value of 32.9 kJ/mol. Further, MOF1 acts as an efficient recyclable heterogeneous catalyst for cycloaddition of CO2 with epoxides to generate cyclic carbonates with high selectivity and yield at mild conditions of RT and 1 bar of CO2. More interestingly, the rate of catalytic conversion of CO2 was enhanced with irradiation of visible light owing to good visible light absorption property of the porphyrin linker. The enhanced catalytic activity of MOF1 under the irradiation of visible-light has been attributed to the in situ generation of thermal energy by photo-thermal effect. Therefore, herein, for the first time, visible-light-assisted efficient cycloaddition of CO2 with epoxides catalyzed by a Mn(II)-porphyrin MOF has been reported.

Progress in the Heterogeneous Catalytic Cyclization of CO2 with Epoxides Using Immobilized Ionic Liquids

Ionic liquid heterogeneous catalysis has become a new catalytic method for carbon dioxide cycloaddition because of its high catalytic activity, green efficiency, easy separation and recovery. In this paper, the research progress of the cycloaddition reaction of carbon dioxide and epoxy compounds with the ionic liquid solid catalyst supported by silica gel, molecular sieve, organic polymer material, carbon material and metal organic frameworks was reviewed. The structure characteristics and catalytic effects of supported ionic liquid catalysts with different supports were summarized and the prospect of new supported ionic liquid catalysts, such as column aromatic hydrocarbons, was prospected.

ImX-MCM-41 (X = Cl, Br and I): Active catalysts for the solvent free synthesis of phenyl glycidyl carbonate

The ImX-MCM-41 (X = Cl, Br and I) catalysts were synthesized via grafting technique using MCM-41 synthesized by simple sol-gel method. These catalysts were characterized using FT-IR, N2-sorption, 13C CP/MAS NMR, XRD, TEM and SEM/EDS techniques. 13C CP/MAS NMR and FT-IR discovered the effective anchorage of imidazole and 1,2-dihaloethane on the MCM-41. SEM analysis images demonstrated that the catalysts comprise worm-like agglomerated structure which was alike to MCM-41. The catalysts were then used in cycloaddition of carbon dioxide and phenyl glycidyl ether under solvent less and co-catalyst free conditions. Among the prepared catalyst, ImBr-MCM-41 showed higher catalytic activity (96.7%) under ambient reaction conditions (100 °C, 20 bar initial CO2 pressure, 300 mg catalyst mass and 3 h). It was found that the use of ImI-MCM-41 and ImCl-MCM-41 resulted in a conversion of 77.3% and 26.4% respectively under the same reaction conditions. These results verified that the synergic effect owing to the strong nucleophilic characteristics of Br− and amine could have promoted the reaction efficiently. The catalyst was reproduced and reused four times without a substantial decrease in performance or product selectivity. A possible site for CO2 activation by ImBr-MCM-41 catalyst has been proposed.

Cycloaddition of Carbon Dioxide to Epoxides for the Synthesis of Cyclic Carbonates with a Mixed Catalyst of Layered Double Hydroxide and Tetrabutylammonium Bromide at Ambient Temperature

AbstractA series of nickel‐aluminium, cobalt‐aluminium and zinc‐aluminum layered double hydroxides were synthesized by urea hydrolysis (UH) and reverse micelle (RM) methods and then applied for the cycloaddition of carbon dioxide to propylene oxide (PO) under solvent‐free and ambient conditions. The most efficient catalyst was zinc‐aluminum layered double hydroxide prepared by RM (denoted as ZnAl‐RM) and it showed, in the presence of a co‐catalyst of tetrabutylammonium bromide, 96% propylene carbonate (PC) yield in 12 h at 25 °C and 1 MPa carbon dioxide. It is noteworthy for the same catalyst system that 74% PC yield was achieved in 24 h at room temperature (about 25 °C) and atmospheric carbon dioxide pressure. The high catalytic performance of the ZnAl‐RM and tetrabutylammonium bromide system should result from cooperative effects between zinc ion and bromine ion. Moreover, the ZnAl‐RM and tetrabutylammonium bromide system showed excellent versatility, which was also an active catalyst to the transformation of carbon dioxide and other epoxides into corresponding cyclic carbonates under mild temperature and pressure conditions.magnified image

Novel and effective strategy of dual bis(trifluoromethylsulfonyl)imide imidazolium ionic liquid immobilized on periodic mesoporous organosilica for greener cycloaddition of carbon dioxide to epoxides

Novel periodic mesoporous organosilica supported ionic liquids were prepared, characterized and evaluated as catalysts for cycloaddition of CO2 to epoxides.

Assessing the pKa‐Dependent Activity of Hydroxyl Hydrogen Bond Donors in the Organocatalyzed Cycloaddition of Carbon Dioxide to Epoxides: Experimental and Theoretical Study

AbstractThe development of hydrogen bond donors (HBDs) as catalytic moieties in the cycloaddition of carbon dioxide to epoxides is an active field of research to access efficient, inexpensive and sustainable metal‐free systems for the conversion of carbon dioxide to useful chemicals. Thus far, no systematic attempt to correlate the activity of a diverse selection of HBDs to their physico‐chemical properties has been undertaken. In this work, we investigate factors influencing the catalytic activity of hydroxyl HBDs from different chemical families under ambient conditions by considering the HBDs Brønsted acidity (expressed as pKa), the number of hydroxyls and structural aspects. As an effect, this study highlights the crucial role of the hydroxyl protons’ Brønsted acidity in determining the catalytic activity of the HBDs, identifies an ideal range for the hydroxyl HBDs proton acidity (9 <pKa <11) and leads to a revaluation of phenol and to the discovery of a simple ascorbic acid derivative as efficient HBDs for the title cycloaddition reaction. Density functional theory (DFT) calculations show mild reactions barriers for the reaction catalysed by phenol and suggest the occurrence of aggregation between molecules of ascorbic acid as a further factor affecting catalytic activity.magnified image

A Pseudodearomatized PN3P*Ni-H Complex as a Ligand and σ-Nucleophilic Catalyst.

In contrast to the conventional strategy of modifying the reactivities and selectivities of the transition metal and organocatalysts by varying the steric and electronic properties of organic substituent groups, we hereby demonstrate a novel approach that the sigma (σ) nucleophilicity of the imine arm can be significantly enhanced in a pseudodearomatized PN3P* pincer ligand platform to reach unprecedented N-heterocyclic carbene-like reactivity. Accordingly, the imine arm of the PN3P*Ni-H pincer complex efficiently catalyzes the hydrosilylation of aldehydes, cycloaddition of carbon dioxide (CO2) to epoxides, and serves as a ligand in the Ru-catalyzed dehydrogenative acylation of amines with alcohols.

Quaternary phosphonium cationic ionic liquid/porous metal–organic framework as an efficient catalytic system for cycloaddition of carbon dioxide into cyclic carbonates

Global warming and climate change concerns are triggering worldwide interest for sustainable transformation of CO2 into useful chemicals. Here, a new and efficient multifunctional catalytic system for the cycloaddition of carbon dioxide with epoxides to synthesize cyclic carbonates under mild and solvent-free reaction conditions has been developed. The catalytic tests revealed that [P12,4,4,4]Br/MIL-53(Cr) (MIL: Materials of Institut Lavoisier) was the best and powerful catalytic system in the cycloaddition with excellent yields (96–99%) under solvent-free condition and 100 °C, 1.0 MPa for 2–3 h. The synergistic effect of anion and cation of ionic liquid [P12,4,4,4]Br as well as the chromium site of cocatalyst MIL-53(Cr) contributed to the excellent catalytic activity. The present catalytic system has several unique features such as simple operation, good to excellent yields, high catalytic activity, environmentally benign and safe. This study provides a sustainable and efficient synergistic strategy for chemical carbon dioxide fixation via the combination of ionic liquids and metal–organic frameworks.

Carbonate synthesis from carbon dioxide and cyclic ethers over methylated nitrogen-substituted mesoporous silica

Methylated nitrogen-substituted mesoporous silica, MeNSBA-15, was found to catalyze cyclic carbonate synthesis via cycloaddition of carbon dioxide with cyclic ethers. Moreover, comparisons with the control measurements over NSBA-15 and SBA-15 samples revealed that methylation was the key functionalization to enhance the nucleophilicity high enough for the reaction. Discussions based on spectroscopic and elemental analyses suggested that the catalyst possesses surface methylated nitrogen paired sites. The kinetic analysis of propylene carbonate synthesis over MeNSBA-15 were performed, and the interpretation of the turn-over frequency of the products clarified the mechanism of propylene carbonate formation mechanism. The most plausible mechanism is proposed to be a Langmuir-Hinshelwood type mechanism involving a kinetically relevant bimolecular reaction step over the methylated-nitrogen pair sites. Furthermore, the proposed reaction mechanism was also indirectly supported by the unique correlation between turn-over frequency and proton affinity of the reactant molecule.

Titanium Incorporated Mesoporous Silica Immobilized Functional Ionic Liquid as an Efficient Reusable Catalyst for Cycloaddition of Carbon Dioxide to Epoxides

AbstractA series of functionalized ionic liquids immobilized onto SBA‐15 mesoporous materials were prepared, characterized and evaluated as catalysts in cycloaddition of CO2 to epoxides. Most of these immobilized ILs perform well in the reaction, especially the multifunctional titanium incorporated SBA‐15 immobilized heterogeneous catalysts Ti‐SBA‐15@ILClCH2COO(0.5) and Al‐SBA‐15@ILClCH2COO(0.5). The catalytic tests revealed that Ti‐SBA‐15@ILClCH2COO(0.5) was the best and powerful catalyst in the cycloaddition for the preparation of cyclic carbonates with high to excellent yields. The heterogeneous catalyst can be easily separated from the reaction mixture by filtration and reused in six consecutive cycles without significant loss in catalytic activity. The studies demonstrate that the well designed supported catalysts via cooperative catalysis of the supported carrier, anion sites of ILs is a promising platform for construction of novel and highly efficient catalytic transformation systems.

Tin(IV) Sulfide Greatly Improves the Catalytic Performance of UiO‐66 for Carbon Dioxide Cycloaddition

AbstractTo overcome the limitations of metal–organic frameworks (MOFs) for catalysis (e.g., low catalytic activities resulting from blockage of the active metal centers by organic linkers) is of great importance. Herein, we demonstrate the formation of UiO‐66 nanoparticles with ultrasmall size and linker defects with the aid of SnS2 nanosheets. The UiO‐66 nanoparticles supported by SnS2 nanosheets were found to exhibit excellent catalytic activity for the cycloaddition reaction of CO2 with propylene oxide under solvent‐free and co‐catalyst‐free conditions. Outstandingly, the catalytic activity was 11 times higher than that of the pure UiO‐66 catalyst under optimum conditions. We thus provide a promising route to modify MOF particles thus to promote their catalytic performance.

Correction to: Heterogeneous cycloaddition of styrene oxide with carbon dioxide for synthesis of styrene carbonate using reusable lanthanum–zirconium mixed oxide as catalyst

Development of environmentally benign green processes for utilization of carbon dioxide to synthesize value-added compounds using heterogeneous catalysis is desirable. One such proposed process is the cycloaddition of styrene oxide with carbon dioxide to synthesize styrene carbonate, synthesis of which has been well studied using various homogenous catalysts. The aim of the current work was to develop an active, selective and reusable heterogeneous catalyst for the cycloaddition of carbon dioxide to styrene oxide. Various solid catalysts such as 0.1% Li/MgO, calcined hydrotalcite (CHT), La–Zr mixed oxide (1:3 La/Zr), 0.1% La/MgO and ZrO2 were employed for cycloaddition of carbon dioxide to styrene oxide. Carboxylation of styrene oxide with carbon dioxide is enhanced by catalysts having both strong basic sites and weak acidic sites. Lanthanum–zirconia mixed oxide was prepared by combustion method using different compositions and evaluated for this reaction. La/Zr ratio of 1:3 was found to be the best among all studied and gave 90% conversion of styrene oxide with 100% selectivity of styrene carbonate at moderate temperature and pressure conditions in 3 h. The catalyst was characterized by various techniques to understand its textural properties. The catalyst was reused over three cycles without any loss of activity. The optimum reaction conditions were obtained by studying all process parameters in a laboratory batch stirred tank reactor (speed of agitation-1000 rpm, catalyst loading-2 × 10−2 g/cm3, 0.01 mol styrene oxide, DMF as solvent (total volume 30 mL), CO2 pressure-2.5 MPa, 130 °C). A detailed mathematical model was developed using Langmuir–Hinshelwood-Hougen–Watson mechanism in the absence of any transport resistances. The activation energy was calculated as 19.1 kcal/mol. The process is green and clean.

Exceptionally Stable and 20-Connected Lanthanide Metal–Organic Frameworks for Selective CO2 Capture and Conversion at Atmospheric Pressure

Highly thermal and chemically stable, 20-connected lanthanide metal–organic frameworks (MOFs) [{Ln(BTB)(H2O)}·H2O]n (where Ln = Sm (MOF1)/Gd (MOF2), BTB = 1,3,5-tris (4-carboxy phenyl) benzene) have been synthesized solvothermally and characterized by single-crystal X-ray diffraction analysis and other physicochemical methods. MOF1 and 2 are isostructural and feature three-dimensional honeycomb-like structure with large one-dimensional hexagonal channels of dimension ∼10.20 × 10.11 A2. Gas uptake studies of the samples revealed selective adsorption properties of MOF1 for CO2 over other (N2, Ar, and H2) gases. The activated samples of the MOF1/2 act as efficient recyclable catalysts for heterogeneous cycloaddition of CO2 with styrene oxide, resulting in cyclic carbonate with high yield and selectivity. Interestingly, the pore size-dependent catalytic conversion of epoxides has been observed, suggesting the potential utility of MOF1 as a promising heterogeneous catalyst for cycloaddition of carbon dioxide. ...