Reaction Of Dioxide Research Articles

Design and synthesis of pyridinamide functionalized ionic liquids for efficient conversion of carbon dioxide into cyclic carbonates

Novel and facilely prepared 2-pyridinamide-functionalized ionic liquids 1–4 (PAIL1–4) were explored for the cycloaddition reaction of carbon dioxide with various epoxides to generate cyclic carbonates. The optimum temperature, CO2 pressure, and catalyst dosage of the cycloaddition reaction, are 60 °C, 0.5 MPa, and 5 mol% respectively. The synthesized N, N-dimethyl-N-(2-oxo-2-(pyridin-2-ylamino)ethyl)butan-1-aminium iodide (PAIL-3) exhibited brilliant catalytic activities under mild conditions with nearly quantitative selectivity and conversion in the absence of any solvents, or metal co-catalysts. The catalyst PAIL-3 could be recycled 4 times without obvious loss of its catalytic activity. Moreover, a plausible mechanism is proposed based on the NMR experiments. The designed pyridinamide functionalized ionic liquids integrated pyridine unit, halogen anion and the N-H moiety in amide and they have an excellent synergistic catalytic effect in promoting the coupling reactions of carbon dioxide and epoxides.

Porous polymeric metalloporphyrin obtained through Sonogashira coupling: Catalytic performance at CO2 cycloaddition to epoxides

Using metal complexes of (5,10,15,20-tetrakis(p-bromophenyl) porphyrin) (MT4BrPP) (M ​= ​Co, Mn) and 4,4-diethynylbiphenyl as monomers, a porous polymeric metalloporphyrin [PoP(MTPP), M ​= ​Co, Mn] was successfully synthesized by Sonogashira cross-coupling reaction. Their morphology, structure and elements were characterized and analyzed by scanning electron microscopy (SEM), Fourier-Transform infrared spectroscopy (FT-IR), X-ray photoelectron spectra (XPS), thermogravimetric analysis (TG), and brunauer-emmett-teller (BET), which indicated high specific surface area and good thermal stability. Then, using PoP(MTPP) as porous catalyst with two-dimensional structure, the cycloaddition reaction of epoxides and carbon dioxide (CO2), for reducing greenhouse gas emissions, was effectively executed without solvents, and the yield of cyclocarbonate got to 90%. In summary, a novel metalloporphyrin based porous polymers were prepared by coupling reaction, and catalytic active centers were effectively fixed in two-dimensional networks, which improved its stability and excellently enhanced their catalytic performance. It’s a competitively candidates for catalyzing the cycloaddition reaction without solvent.

Uniform Core-Shell Microspheres of SiO2@MOF for CO2 Cycloaddition Reactions.

A SiO2@MOF core-shell microsphere for environmentally friendly applications was introduced in this study. Several types of metal-organic framework core-shell microspheres were successfully synthesized. To achieve high stability and favorable catalytic performance, modification and coating methods were necessary for optimization. The improved SiO2@MOF core-shell microspheres were used in the cycloaddition reaction of carbon dioxide and propylene oxide. Dispersion ability was enhanced by the addition of core-shell microspheres, which also produced high catalytic activity. Accompanied with tetrabutylammonium bromide as a co-catalyst, SiO2@ZIF-67 had a maximum conversion of 97%, and the results revealed that SiO2@ZIF-67 could be used for 5 reaction cycles while maintaining high catalytic performance. This recycling catalyst was also reacted with a series of terminal epoxides to form corresponding cyclic carbonates with high conversion rates, indicating that SiO2@MOF core-shell microspheres exhibit promise in the field of catalysis.

Influence of the gas model on the boundary layer characteristic parameters and transition prediction for the Mars entry capsule

<p indent="0mm">Turbulent transition is an important factor affecting the thermal environment of spacecraft. A boundary layer transition prediction method was developed for both smooth and rough thermal protection system surfaces of a large-scale entry capsule in the process of entering the Martian atmosphere. The effects of the gas model and wall temperature constraints on the boundary layer characteristic parameters and transition features were analyzed. The results indicate that the dissociation reaction of carbon dioxide and its thermodynamic non-equilibrium effect will lead to increases in the momentum thickness Reynolds number and the roughness-height-based Reynolds number of the boundary layer. The radiative-equilibrium wall temperature constraint also results in a higher momentum thickness Reynolds number and roughness-height-based Reynolds number compared to those of the cold wall conditions. Therefore, the thermochemical non-equilibrium and radiative-equilibrium wall temperature boundary condition should be included in the analysis model to obtain the actual transition features.

Heterogeneous reaction of SO2 on CaCO3 particles: Different impacts of NO2 and acetic acid on the sulfite and sulfate formation

Despite the heterogeneous reaction of sulfur dioxide (SO2) on mineral dust particles significantly affects the atmospheric environment, the effect of acidic gases on the formation of sulfite and sulfate from this reaction is not particularly clear. In this work, using the in-situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) technique, we employed a mineral dust particle model (CaCO3) combined with NO2 and acetic acid to investigate their effects on the heterogeneous reaction of SO2 on CaCO3 particles. It was found that water vapor can promote the formation of sulfite and simulated radiation can facilitate the oxidation of sulfite to sulfate. The addition of NO2 or acetic acid to the reaction system altered the production of sulfate and sulfite accordingly. There was a synergistic effect between NO2 and SO2 that promoted the oxidation of sulfite to sulfate, and a competitive effect between acetic acid and SO2 that inhibited the formation of sulfite. Moreover, light and water vapor can also affect the heterogeneous reaction of SO2 with the coexistence of multiple gases. These findings improve our understanding of the effects of organic and inorganic gases and environmental factors on the formation of sulfite and sulfate in heterogeneous reactions.

Preparation of a Photosensitive Composite Carbon Fiber for Spilled Oil Cleaning

This paper deals with preparing a functional composite carbon fiber with a large surface area for spilled oil cleaning. The composite fiber consisted of photosensitive oxide particles and polymer-derived carbon. It was made by co-spinning the polymer and metallic compounds. After heat treatment at high temperatures, an activated carbon fiber containing oxide particles was obtained. The particles were found distributed in the fiber and at the surface of the fiber. The composite fiber was found sensitive to sunlight. Fiber mats made of the composite fiber possessed a high surface area for oil absorption and removal. Cobalt(II) titanate particles were obtained from the reaction of titanium dioxide and cobalt oxide. The reaction happened in situ through the hydrolysis of metallic compounds in the spun fiber. The titanium dioxide and cobalt(II) titanate particle-containing fibers demonstrated the photoactivity in the visible light spectrum. It was concluded that particle-containing composite carbon fiber mats can be prepared successfully by co-electrospinning. Due to the oleophilic property and the high active surface area, the composites are suitable for spilled oil cleaning through fast absorption.

Photoredox-catalyzed reaction of thianthrenium salts, sulfur dioxide and hydrazines

A photoredox-catalyzed reaction of thianthrenium salts, hydrazines and DABCO·(SO2)2 is accomplished, providing diverse arenesulfonohydrazides in moderate to good yields under mild reaction conditions.

The reduction reaction of carbon dioxide on a precise number of Fe atoms anchored on two-dimensional biphenylene.

In recent accomplishments, a new two-dimensional allotrope of carbon-biphenylene (BP) was experimentally synthesized [Fan et al., Science, 372, 852-856 (2021)]. The BP sheet is composed of four-, six-, and eight-membered carbon rings constructed using periodically arranged sp2-hybridized carbon atoms. Unlike semi-metallic graphene, BP is metallic with quite active atoms and chemical bonds, and the binding strength with reaction intermediates will be enhanced, which means that it may exhibit good catalytic activity in some electrochemical catalytic reactions. Using spin-polarized density functional theory based on first-principles simulations and ab initio molecular dynamic calculations, we systematically investigated the structure, thermodynamic stability, CO2 reduction reaction (CO2RR) activity and product selectivity of a precise number of Fen (n = 1-3) atoms embedded on a BP monolayer. The calculated results indicate that our designed Fe1@BP, Fe2@BP and Fe3@BP complexes possess good thermodynamic and electrochemical stabilities and strong absorption for CO2, which promotes the activation of CO2. Furthermore, the Fe2@BP catalyst possesses good catalytic ability for the CO2RR to CH3OH due to a small rate determining potential of -0.48 V. In addition, Fe2- and Fe3@BP catalysts demonstrate superior catalytic performance for the CO2RR to CH4 with low rate-limiting steps. More importantly, both the Fe2 and Fe3@BP catalysts can effectively suppress the hydrogen evolution reaction (HER) during the entire CO2RR process. The electronic structure analysis shows that the enhanced ability of Fe1-3@BP catalysts for effective CO2 reduction can be attributed to the establishment of strong hybridization between Fe-3d and O-2p or C-2p states, which is conducive to the transfer of strong electrons to the anti-bond orbital of CO2. This work provides an in-depth insight into the intrinsic catalytic mechanisms of the CO2RR on Fe1-3@BP catalysts, and highlights the excellent performance of the BP sheet as a substrate material for the polyatomic catalyst.

Synthesis of nucleoside-substituted carbonate and diol derivatives through the carbon dioxide reaction using polyionic liquid catalysts

Under the combined action of water and polyionic liquids, nucleoside drug intermediates was synthesized through CO2 conversion.

Atmospheric nitrate formation pathways in urban and rural atmosphere of Northeast China: Implications for complicated anthropogenic effects

Effects of human activities on atmospheric nitrate (NO3-) formation remain unclear, though the knowledge is critical for improving atmospheric chemistry models and nitrogen deposition reduction strategies. A potentially useful way to explore this is to compare NO3- oxidation processes in urban and rural atmospheres based upon the oxygen stable isotope composition of NO3- (Δ17O–NO3-). Here we compared the Δ17O–NO3- from three-years of daily-based bulk deposition in urban (Shenyang) and forested rural sites (Qingyuan) in northeast China and quantified the relative contributions of different formation pathways based on the SIAR model. Our results showed that the Δ17O in Qiangyuan (26.2 ± 3.3‰) is significantly higher (p < 0.001) than in Shenyang (24.0 ± 4.0‰), and significantly higher in winter (Shenyang: 26.1 ± 6.7‰, Qingyuan: 29.6 ± 2.5‰) than in summer (Shenyang: 22.7 ± 2.9‰, Qingyuan: 23.8 ± 2.4‰) in both sites. The lower values in the urban site are linked with conditions that favored a higher relative contribution of nitrogen dioxide reaction with OH pathway (0.76-0.91) than in rural site (0.47-0.62), which should be induced by different levels of human activities in the two sites. The seasonal variations of Δ17O–NO3- in both sites are explained by a higher relative contribution of ozone-mediated oxidation chemistry and unfavorable conditions for the OH pathway during winter relative to summer, which is affected by human activities and seasonal meteorological condition change. Based on Δ17O, wintertime conditions led to a contribution of O3 related pathways (NO3 + DMS/HC and N2O5 hydrolysis) of 0.63 in Qingyuan and 0.42 in Shenyang, while summertime conditions led to 0.15 in Qingyuan and 0.05 in Shenyang. Our comparative study on Δ17O–NO3- between urban and rural sites reveals different anthropogenic effects on nitrate formation processes on spatial and temporal scales, illustrating different responses of reactive nitrogen chemistry to changes in human activities.

The Effect of Durability and Corrosion Behavior on the Concrete Treated with Chemical Inhibitor

Chloride-induced corrosion of steel reinforcement and the reaction of atmospheric carbon dioxide with cement paste are the most important causes of premature failure in marine-reinforced concrete structures. Among the available methods, corrosion inhibitors offer a simple and costeffective technique in reducing the chloride-induced corrosion on the steel reinforced concrete.

Density functional theory study of CO2 reduction to CH3OH on the surfaces of metal (Cu, Ni, and Mn)-doped carbon nanotubes

The reduction reaction of carbon dioxide (RR-CO2) to CH3OH using metal catalysts can reduce the energy required by this process. In this study, we investigated the RR-CO2 mechanisms with Cu-, Ni-, and Mn-doped carbon nanotubes (CNTs). The substitutional (doping with carbon atom) positions in CNTs are suitable sites for adsorbing Cu, Ni, and Mn metals. The reaction paths to the RR-CO2 were investigated in the gas and solvent phases. The results demonstrated that the overpotential values with Cu-, Ni-, and Mn-doped CNT(8, 0) and CNT(6, 6) catalysts in the gas and solvent phases were lower than that obtained with metal catalysts in previous studies (−1.116 V). Thus, metal-doped CNT(8, 0) and CNT(6, 6) catalysts with low overpotentials could be applied in the RR-CO2.

Nickel single-atom catalysts intrinsically promoted by fast pyrolysis for selective electroreduction of CO2 into CO

The electrochemical reduction reaction of carbon dioxide (CO2RR) is an effective way towards carbon neutralization. Single-atom catalysts (SACs) are expected to be efficient for CO2RR due to maximum atom utilization and excellent catalytic performance. Here, nitrogen-doped carbon supported Ni SACs (Ni-SAC@NCs) were prepared through effective fast pyrolysis. CO2 can convert into CO efficiently with Ni-SAC@NCs as electrocatalysts for CO2RR. The faradaic efficiency kept well above 80% in the applied potential window of −0.6 to −0.9 V (vs. reversible hydrogen electrode (RHE)), with a highest FECO of 95% at −0.6 V (vs. RHE). Ni-SAC@NCs can achieve the best CO selectivity under a small overpotential, surpassing most other state-of-the-art catalysts. Computations also indicate that the unique defect-Ni-N3 structure is the active site. This work not only provides a simple and promising new route for the preparation of SACs, but also proves the key role of the coordination environment in electrocatalysis.

Investigation on the Suitability of Engelhard Titanium Silicate as a Support for Ni-Catalysts in the Methanation Reaction

Methanation reaction of carbon dioxide is currently envisaged as a facile solution for the storage and transportation of low-grade energies, contributing at the same time to the mitigation of CO2 emissions. In this work, a nickel catalyst impregnated onto a new support, Engelhard Titanium Silicates (ETS), is proposed, and its catalytic performance was tested toward the CO2 methanation reaction. Two types of ETS material were investigated, ETS-4 and ETS-10, that differ from each other in the titanium content, with Si/Ti around 2 and 3% by weight, respectively. Catalysts, loaded with 5% of nickel, were tested in the CO2 methanation reaction in the temperature range of 300–500 °C and were characterized by XRD, SEM–EDX, N2 adsorption–desorption and H2-TPR. Results showed an interesting catalytic activity of the Ni/ETS catalysts. Particularly, the best catalytic performances are showed by Ni/ETS-10: 68% CO2 conversion and 98% CH4 selectivity at T = 400 °C. The comparison of catalytic performance of Ni/ETS-10 with those obtained by other Ni-zeolites catalysts confirms that Ni/ETS-10 catalyst is a promising one for the CO2 methanation reaction.

Ab-Initio Molecular Dynamics Simulation of Condensed-Phase Reactivity: The Electrolysis of Ammonia and Ethanimine in Aquatic Carbon Dioxide Solutions

The re-use of wastewater is an increasingly important subject. Most recently, several attempts were reported to convert wastewater in harmless or even valuable substances by the use of electrical current. Electrochemistry is an old approach. The renewed interest stems from the fact that electrical current is often available in abundance, for example from solar energy in arid regions, while clean water is not. Experimentally, one has to deal with very many products which are the result of many reaction steps. Here, theory can help. Using Car–Parrinello molecular dynamics, we simulate the first few reaction steps of the electrolysis of wastewater. On the basis of previous studies, we investigate the reaction of carbon dioxide and nitrogen compounds. The results show a great variety of reaction steps and resulting products. Some of them are technologically interesting, such as hydrogen and formic acid.

Study of the Cycloaddition of CO2 with Styrene Oxide Over Six-Connected spn Topology MOFs (Zr, Hf) at Room Temperature.

A series of MOFs with a 6-connected spn topology were synthesized (MOF-808-(Zr, Hf), PCN-777-(Zr, Hf), MOF-818-(Zr, Hf)). Through the in situ DRIFTS of NH3 adsorption-desorption, we found that the activated catalyst mainly contains Lewis acid sites. The effects of different organic ligands on the Lewis acid of the Zr6 cluster were analyzed by XPS and NH3 -TPD, and the relative Lewis acidity of the same metal was obtained: PCN-777>MOF-808>MOF-818. In the Py-FTIR results, we confirmed that MOF-818 has a higher acid site density. In the activity test, MOFs with mesoporous structure showed better catalytic activity under normal temperature and pressure. Among them, MOF-818 can still maintain a high degree of crystallinity after catalysis. Finally, we use density functional theory to propose the mechanism of the cycloaddition reaction of carbon dioxide and styrene oxide. The results show that the metal is coordinated with styrene oxide and halogens attack the β carbon of the epoxide.

Study of potential of Fe-Si76 as catalyst for CO2 reduction to CH3OH

In this study, mechanisms of reduction reaction of carbon dioxide on Iron doped silicon nanocage are investigated in gas phase and water. The metal catalysts have several fundamental problems such as slow kinetics, high over potential, low performance and insignificant selectivity. The reaction pathways of carbon dioxide conversion to methanol are examined by theoretical methods in gas phase and water. The acceptable reaction pathway is identified from thermodynamic view point in gas phase ad water. Results indicated that the in carbon dioxide conversion to methanol the reaction step of 4 is the rate-limiting step. Results indicated that the over potential (−0.825 V) of reaction steps in gas phase and water is lower than metal catalysts (−1.116 V). The Iron doped silicon nanocage with low barrier energies and low over potential is proposed as efficient catalyst in gas phase and water.

Non-Noble-Metal Metal–Organic-Framework-Catalyzed Carboxylative Cyclization of Propargylic Amines with Atmospheric Carbon Dioxide under Ambient Conditions

The coupling reaction of propargylic amines and carbon dioxide (CO2) to synthesize 2-oxazolidinones is an important reaction in industrial production, and yet harsh reaction conditions and noble-metal catalysts are often required to achieve high product yields. Herein, one novel noble-metal-free three-dimensional framework, [Mg3Cu2I2(IN)4(HCOO)2(DEF)4]n (1), assembled by magnesium and copper clusters was synthesized and applied to this reaction. Compound 1 displays excellent solvent stability. Importantly, 1, acting as heterogeneous catalyst, can highly catalyze the cyclization of propargylic amines with CO2 under atmospheric pressure at room temperature, which can be recycled at least five times without an obvious decrease of the catalytic activity. NMR spectroscopy, coupled with 13C-isotope- and deuterium-labeling experiments, clearly clarifies the mechanism of this catalytic system: CO2 was successfully captured and converted to the product of 2-oxazolidinones, the C≡C bond of propargylic amines can be effectively activated by 1, and proton transfer was involved in the reaction process. Density functional theory calculations are further conducted to uncover the reaction path and the crucial role of compound 1 during the reaction.

Double-Layer Nitrogen-Rich Two-Dimensional Anionic Uranyl-Organic Framework for Cation Dye Capture and Catalytic Fixation of Carbon Dioxide.

A novel two-dimensional double-layer anionic uranyl-organic framework, U-TBPCA {[NH2(CH3)2][(UO2)(TBPCA)], where H3TBPCA = 4,4',4″-s-triazine-1,3,5-triyltripamino-methylene-cyclohexane-carboxylate}, with abundant active sites and stability was obtained by assembling UO2(NO3)2·6H2O and a triazine tricarboxylate linker, TBPCA3-. Due to the flexibility of the ligand and diverse coordination modes between carboxyl groups and uranyl ions, U-TBPCA exhibits an intriguing topological structure and steric configuration. This double-layer anionic uranyl-organic framework is highly porous and can be used for selective adsorption of cationic dyes. Due to the presence of high-density metal ions and basic -NH- groups, U-TBPCA acts as an effective heterogeneous catalyst for the cycloaddition reaction of carbon dioxide with epoxy compounds. Moreover, the various modes of coordination between the tricarboxylic ligand and uranyl ion were studied by density functional theory calculations, and several simplified models were established to probe the influence of hydrogen bonding between carbon dioxide and U-TBPCA on the ability of U-TBPCA to bind carbon dioxide. This work should aid in improving our understanding of the coordination behavior of uranyl ion as well as the development and utilization of new actinide materials.

Full-Spectrum Fluoromethyl Sulfonation via Modularized Multicomponent Coupling

Full-Spectrum Fluoromethyl Sulfonation via Modularized Multicomponent Coupling