Carbon Dioxide Utilization Research Articles

Solvent-free catalytic synthesis of ureas from amines and carbon dioxide under atmospheric pressure using oxovanadium(V) catalyst with silylating reagent

Abstract Efficient utilization of carbon dioxide for the synthesis of valuable compounds is considered to be essential for the future sustainable society. Herein, N,O-bis(trimethylsilyl)acetamide (BSA), which acts not only as a silylating reagent but also as a reaction solvent, was demonstrated to facilitate the solvent-free catalytic synthesis of ureas in one-step from amines and carbon dioxide under atmospheric pressure using a commercially available air-stable NH4VO3 catalyst. This catalytic system was applicable to a wide range of substrate and a gram-scale reaction. One-step preferential synthesis of unsymmetrical ureas was also realized.

ZIF-8 Porous Liquids with Different Sterically Hindered Solvents and Porous Guests for Catalytic Conversion of Carbon Dioxide.

Utilizing carbon dioxide (CO2) as a raw material is an effective way to reduce carbon emissions, and developing catalytic systems with high catalytic activity and stability is crucial for the efficient utilization of CO2. Porous liquids (PLs) with both permanent pores and fluidity have great potential in the fields of catalysis, gas sorption, and storage. Nevertheless, the catalytic performance of PLs is affected by many factors; therefore, further study is needed. Herein, we proposed a general strategy to construct a series of type III PLs with different chemical structures of sterically hindered solvents and different microstructures of porous guests. Benefiting from the unique microstructures, the as-prepared PLs exhibit great potential in catalyzing the reaction of CO2 with propylene oxide under suitable conditions. Moreover, their catalytic activity exceeds that of pure sterically hindered solvents without a porous guest loading. The influences of the nucleophilicity of the anion of the sterically hindered solvent and the microstructure of the porous guests on the catalytic activity and the catalytic stability of the PLs were analyzed. Meanwhile, the mechanism of the catalytic conversion of CO2 was proposed, which is of great significance for the design and development of the subsequent PL catalysts.

Taming CO2•- via Synergistic Triple Catalysis in Anti-Markovnikov Hydrocarboxylation of Alkenes.

The direct utilization of carbon dioxide as an ideal one-carbon source in value-added chemical synthesis has garnered significant attention from the standpoint of global sustainability. In this regard, the photo/electrochemical reduction of CO2 into useful fuels and chemical feedstocks could offer a great promise for the transition to a carbon-neutral economy. However, challenges in product selectivity continue to limit the practical application of these systems. A robust and general method for the conversion of CO2 to the polarity-reversed carbon dioxide radical anion, a C1 synthon, is critical for the successful valorization of CO2 to selective carboxylation reactions. We demonstrate herein a hydride and hydrogen atom transfer synergy driven general catalytic platform involving CO2•- for highly selective anti-Markovnikov hydrocarboxylation of alkenes via triple photoredox, hydride, and hydrogen atom transfer catalysis. Mechanistic studies suggest that the synergistic operation of the triple catalytic cycle ensures a low-steady-state concentration of CO2•- in the reaction medium. This method using a renewable light energy source is mild, robust, selective, and capable of accommodating a wide range of activated and unactivated alkenes. The highly selective nature of the transformation has been revealed through the synthesis of hydrocarboxylic acids from the substrates bearing a hydrogen atom available for intramolecular 1,n-HAT process as well as diastereoselective synthesis. This technology represents a general strategy for the merger of in situ formate generation with a synergistic photoredox and HAA catalytic cycle to provide CO2•- for selective chemical transformations.

Homogeneous Catalysis in N-Formylation/N-Methylation Utilizing Carbon Dioxide as the C1 Source.

The growing emphasis on sustainable chemistry has driven research into utilizing carbon dioxide (CO2) as a nontoxic, abundant, and cost-effective C1 building block. CO2 offers a promising avenue for direct conversion into valuable chemicals ranging from fuels to pharmaceuticals. This review focuses on the utilization of CO2 for reductive N-formylation/N-methylation reactions of various amines, providing advantages over conventional methods involving toxic CO and other methylating reagents. The approach employs readily available reductants such as silane, borane reagents, and hydrogen (H2). The discussion encompasses recent developments in transition metal and organocatalyst systems for these reactions, highlighting mechanistic interpretations and factors influencing product selectivity.

Modeling and Integration of Green-Hydrogen-Assisted Carbon Dioxide Utilization for Hydrocarbon Manufacturing

Modeling and Integration of Green-Hydrogen-Assisted Carbon Dioxide Utilization for Hydrocarbon Manufacturing

Non-hydrolytic sol-gel synthesis of amine-functionalized silica: Template- and catalyst-free preparation of mesoporous catalysts for CO2 valorization

Carbon dioxide utilization presents an important and topical research topic. However, the performance of catalysts needed for CO2 transformations does not achieve the necessary levels for their widespread application. To this end, we decided to study non-aqueous condensations providing amine-functionalized silica catalysts, possibly active in CO2-epoxide cycloaddition reaction. While non-hydrolytic sol-gel method is well-known for its efficiency in providing highly porous Lewis and Brønsted acid metallosilicates, here we show for the first time its application for the preparation of silica-based catalysts containing basic groups. First, the reaction conditions were screened to reproducibly obtain porous materials with preserved amine moieties. These were identified as follows: silicon tetraacetate and bridging tertiary amine silanes as precursors, toluene as a solvent, and temperature between 160 and 180 °C. In such a way, materials with up to 776 m2 g−1 and 1.58 cm3 g−1 were obtained in one-step process, without any template, after conventional drying step. Next, the amine-functionalized materials were tested in CO2-epoxide coupling providing cyclic organic carbonates with high selectivity (>99 %) and moderate activity (up to 86 % epichlorohydrin conversion after 1 h at 120 °C and 10 bar CO2). The characterization of spent catalysts revealed a presence of cyclic organic carbonates at the catalyst surface as well as conversion of tertiary amine groups to quaternary ammonium moieties.

Non-Noble Metal Anchored 2D Covalent Organic Framework for Ambient CO2 Fixation to High-Value Compounds.

The catalytic functionalization of CO2 into high-value compounds comprises a promising approach to mitigate its atmospheric content and sustainable generation of fine chemicals. Herein, we report application of a crystalline, nano-porous 2D COF (ET-BP-COF) for utilization of CO2. The ET-BP-COF features a unique 2D kagome (kgm) topology composed of hexagonal and triangular 1D channels decorated with bipyridine sites, which were exploited for covalent anchoring of eco-friendly Cu(I) by post-synthetic method. The Cu(I) engrafted COF was applied as a recyclable catalyst for coupling CO2 with alkynes to generate two high-value compounds, α-alkylidene cyclic carbonates (α-ACCs) and 2-oxazolidinones. Notably, Cu(I)@ET-BP-COF demonstrated excellent catalytic performance for transforming propargylic amine and CO2 to 2-oxazolidinone, an essential building block for antibiotics. Besides, an efficient transformation of propargylic alcohols to generate α-ACCs, valuable commodity chemicals, has been achieved by utilizing carbon dioxide. Further, detailed theoretical simulations disclosed the insight mechanistic path of Cu(I) catalyzed coupling of CO2 with alkynes to produce 2-oxazolidinones and α-ACCs. Significantly, Cu(I)@COF was reusable for multiple cycles without losing framework rigidity and catalytic performance. This study showcases the potential application of ET-BP-COF for stable anchoring of eco-friendly metals as catalytic sites for effective utilization of CO2 to produce two high-value products.

Ionic liquid catalysed synthesis of benzimidazolone from Ortho-Phenylenediamine in the presence of carbon dioxide as a carbonyl source under solvent free condition

In this study, we report synthesis of benzimidazolones from o-phenylene diamine by utilizing carbon dioxide as a carbonyl source under mild reaction conditions in the presence of ionic liquid as a catalyst. Six bifunctional protonic ionic liquids (PILs) were synthesised by reacting superbases 1,5,7-Triazabicyclo[4.4.0]dec-5-ene (TBD) and 1,8-diazabicyclo-[5.4.0]undec-7-ene (DBU) with proton donors such as Trifluoroethanol (TFE), Cyclopropane carboxylic acid (CPCA) and 2,2,2-Trifluoroacetic acid (TFA). Among them, [TBDH+][TFE−] was the most effective, achieving high conversion rates of o-phenylene diamine to 2-benzimidazolone at 1 bar CO2 pressure and 60° C. This PIL could be reused for up to six cycles. Our method offers a green and efficient approach for producing 2-benzimidazolone derivatives, with potential applications in pharmaceuticals and materials science.

Molten salt electrolytic CO2-derived NiCo2@C catalysts with enhanced oxygen evolution reaction

Carbon-based nonprecious metallic electrocatalysts have garnered considerable attention due to their tunable structures, rapid electron transfer, and easy characterization. There is great anticipation for the development of green and controllable methods for metal-carbon-based electrocatalysts. Molten salts synthesis offers a green, facile and effective approach for fabricating carbon-based materials, utilizing carbon dioxide (CO2) as the carbon source. In this study, the co-electroreduction of CO2 and the binary metal oxide NiCo2O4 is carried out in a mixture of Li2CO3, Na2CO3, and K2CO3 at 500oC. This process leads to the formation of metal alloy nanoparticles encapsulated in a carbon matrix derived from CO2, referred to as NiCo2@C. The resulting NiCo2@C exhibits low overpotential and Tafel slope (340mV@10mAcm−2, 67mV dec−1) in 0.1M KOH solution for OER, which is superior to the commercial RuO2 (360mV@10mAcm−2, 88mV dec−1). Both experimental and theoretical findings indicate the synergistic effects of Ni/Co bimetallic sites. Spontaneous adsorption of hydroxide ion on the bridging sites of heterologous diatoms facilitates the adsorption and desorption of intermediates during the OER process.

Development and application of carbon dioxide direct mineralization technology and emission reduction device

Abstract This study analyzes the principles and methods of carbon dioxide mineralization fixation to address the challenges posed by global climate and ecological changes, achieve carbon neutrality goals, and solve carbon utilization issues in the development of the fluorosilicon new material industry. The research focuses on the direct mineralization reaction system of carbon dioxide flue gas and the development of a carbon dioxide emission reduction device utilizing wet mineralized gas treatment technology. To implement alkaline waste management for industrial solid waste. The research shows that the wet carbon dioxide mineralization and emission reduction device can make the alkaline solution better mineralize carbon dioxide, avoid the gas discharge too fast and affect the reaction rate. At the same time, the solution is mixed and the exhaust linkage is carried out to further improve the reaction rate, and provide a reference for the development of large-scale carbon dioxide utilization technology suitable for high energy consumption industries.

Enhancing mechanical properties of concrete with 3D printed vascular networks via carbonation strengthening

Vascular systems offer promising potential for enabling self-recovery in cementitious materials, but their construction in three dimensions presents significant challenges. Our group has developed an embedded printing strategy allowing for the freeform construction of 3D hollow vascular channels, overcoming previous limitations. However, concerns persist regarding the weakening of mechanical properties caused by these vascular channels. In this study, we utilize carbon dioxide curing to reinforce the vascular wall, mitigating the mechanical loss associated with hollow vascular channel. We investigate the effect of carbonation on the vascular channel wall's morphology, composition, and microhardness along the radial direction to gain insight into its impact. Additionally, we analyze the influence of both vascular channels and carbonated vascular channels on intensity and cracking behaviors under various loading directions. The findings from this investigation provide essential insights for the design and optimization of vascular networks in concrete structures.

Plasma-Assisted Synthesis of Methanol Through Hydrogenation of Carbon Dioxide With Non-Noble Metal Mixed Oxide Catalysts.

The utilization of carbon dioxide through chemical conversion is a promising approach for the recycling of carbon resources. Despite well-developed industrial processes for CO2 hydrogenation to methanol, the effective use of CO2 as a feedstock remains challenging because of the costly requirements of high temperature and reaction pressure. In this paper, we report the methanol synthesis from CO2 and hydrogen using a dielectric barrier discharge (DBD) reactor under atmospheric pressure with a nickel-cerium-aluminum mixed oxide (Ni/Ce-Al MOx) catalyst. The combined use of plasma and the Ni/Ce-Al MOx catalyst was observed to yield 13.3±0.4 % of methanol, favorably compared to the 2.6±0.5 % yield of the case without catalyst. Microscopy images, selected area electron diffraction patterns, and energy-dispersive X-ray analysis confirmed the presence of fluorite-structured ceria, aluminium, nickel, and nickel oxide particles in the catalyst. The reaction mechanism for the plasma-assisted hydrogenation of CO2 was hypothesized to involve a carbide formation pathway due to the presence of carbide confirmed by X-ray photoelectron spectroscopic characterization.

Using Carbon Dioxide for Subsea Long-Duration Energy Storage

This paper investigates the operating benefits and limitations of utilizing carbon dioxide in hydro-pneumatic energy storage systems, a form of compressed gas energy storage technology, when the systems are deployed offshore. Allowing the carbon dioxide to transition into a two-phase fluid will improve the storage density for long-duration energy storage. A preliminary comparative study between an air-based and a carbon dioxide-based subsea hydro-pneumatic energy storage system is first presented. The analysis is based on thermodynamic calculations assuming ideal isothermal conditions to quantify the potential augmentation in energy storage capacity for a given volume of pressure containment when operating with carbon dioxide in lieu of air. This is followed by a transient thermal analysis of the carbon dioxide-based hydro-pneumatic energy storage system, taking into account the real scenario of a finite thermal resistance for heat exchange between the gas and the surrounding seawater. Results from numerical modelling revealed that the energy storage capacity of a carbon dioxide-based subsea hydro-pneumatic energy storage system operating under ideal isothermal conditions can be theoretically increased by a factor of 2.17 compared to an identical air-based solution. The numerical modelling revealed that, under real conditions under which transient effects resulting from a finite thermal resistance are accounted for, the achievable factor is lower, depending on the charging and discharging time, the initial temperature, and whether a polyethene liner for corrosion prevention is considered or not.

Construction of bicarbonate-porous poly(ionic liquid)s for cycloaddition of CO2 and epoxides under mild conditions

The utilization of carbon dioxide (CO2) as a C1 building block to synthesize cyclic carbonates represents an environmentally and sustainably viable approach. Nevertheless, the preparation of metal- and halogen-free porous materials remains a promising avenue for the cycloaddition reaction. In this context, we have designed a bicarbonate-porous poly(ionic liquid)s (PEI/PS-HCO3) catalyst with a mesoporous structure for the construction of multiple active sites through quaterisation and ion exchange. The as-prepared PEI/PS-HCO3 catalyst exhibited excellent catalytic activity for the synthesis of cyclic carbonates, with yields of up to 93% under metal-, solvent- and halogen-free conditions. Furthermore, the catalyst exhibited excellent reusability by washing with anhydrous ethanol. The feasible reaction mechanism was proposed. The interaction of dual hydrogen bond donors (amine groups and [HCO3]− anion) with epichlorohydrin (ECH) via hydrogen bonding results in the polarisation of the epoxide C-O bond. Amine groups, also acting as Lewis base sites, captured CO₂ to produce carbamates ([NH-COO]−). The nucleophilic [HCO3]− attacked the less sterically hindered β-carbon atom of epichlorohydrin (ECH). This protocol provides a novel strategy for the preparation of halogen-free catalysts.

A simplified method of calculating heat flow through a heat exchanger with a significantly temperature-dependent specific heat of heat transfer fluids

A simplified method of calculating the heat flow through a heat exchanger in which one or both heat-carrying media have a specific heat that varies significantly with temperature is proposed. The proposed method allows for the calculation of the maximum heat flow rate provided that the thermodynamic properties of both heat carriers are known. It is intended for the simplification of heat exchanger modeling at the pre-design power plant simulations, which are used for the assessment of efficiency and the selection of schematic solutions. This is particularly relevant when the parameters of the heat exchangers are not known. The proposed method may prove useful for the simulation of binary cycle geothermal power plants, as well as for the modeling of gas turbine power plants utilizing carbon dioxide as the working medium for their cycles.

Machine learning optimization and 4E analysis of a CCHP system integrated into a greenhouse system for carbon dioxide capturing

The world has seen an increase in the popularity of renewable-based energy systems. However, because of their erratic nature, fossil fuels cannot be entirely phased out. Utilizing carbon dioxide in greenhouses close to power plants and generating extra power electricity from dissipated thermal energy are appealing strategies that cause us to have a cleaner environment and affordable power electricity. To exploit the high enthalpy of expelled gases from a gas turbine, the gas turbine was coupled with an absorption refrigerant cycle and an organic Rankine cycle and analyzed. Additionally, a deep artificial neural network method was used to calculate all functions in a rapid optimization and accurate 4E analysis. The carbon dioxide emissions subsided from 0.9183 to 0.41 kg CO2/s, and the optimization time improved 257 times after using the trained machine learning model. An adsorption technique for CO2 separation is used for the proposed system because of its lower energy consumption. The maximum exergy and energy efficiencies were attained at 36.71 % and 49.2 %, respectively, and parametric studies are being assessed. Due to increases in harvests and efficiencies, the net annual interest has increased by 21.8 %, up to 22.5 million dollars.

Clostridium autoethanogenum alters cofactor synthesis, redox metabolism, and lysine-acetylation in response to elevated H2:CO feedstock ratios for enhancing carbon capture efficiency

BackgroundClostridium autoethanogenum is an acetogenic bacterium that autotrophically converts carbon monoxide (CO) and carbon dioxide (CO2) gases into bioproducts and fuels via the Wood–Ljungdahl pathway (WLP). To facilitate overall carbon capture efficiency, the reaction stoichiometry requires supplementation of hydrogen at an increased ratio of H2:CO to maximize CO2 utilization; however, the molecular details and thus the ability to understand the mechanism of this supplementation are largely unknown.ResultsIn order to elucidate the microbial physiology and fermentation where at least 75% of the carbon in ethanol comes from CO2, we established controlled chemostats that facilitated a novel and high (11:1) H2:CO uptake ratio. We compared and contrasted proteomic and metabolomics profiles to replicate continuous stirred tank reactors (CSTRs) at the same growth rate from a lower (5:1) H2:CO condition where ~ 50% of the carbon in ethanol is derived from CO2. Our hypothesis was that major changes would be observed in the hydrogenases and/or redox-related proteins and the WLP to compensate for the elevated hydrogen feed gas. Our analyses did reveal protein abundance differences between the two conditions largely related to reduction–oxidation (redox) pathways and cofactor biosynthesis, but the changes were more minor than we would have expected. While the Wood–Ljungdahl pathway proteins remained consistent across the conditions, other post-translational regulatory processes, such as lysine-acetylation, were observed and appeared to be more important for fine-tuning this carbon metabolism pathway. Metabolomic analyses showed that the increase in H2:CO ratio drives the organism to higher carbon dioxide utilization resulting in lower carbon storages and accumulated fatty acid metabolite levels.ConclusionsThis research delves into the intricate dynamics of carbon fixation in C. autoethanogenum, examining the influence of highly elevated H2:CO ratios on metabolic processes and product outcomes. The study underscores the significance of optimizing gas feed composition for enhanced industrial efficiency, shedding light on potential mechanisms, such as post-translational modifications (PTMs), to fine-tune enzymatic activities and improve desired product yields.

Kinetic insights into energy-saving and low-carbon reactive distillation processes for the transesterification to dimethyl carbonate

The transesterification of propylene carbonate (PC) or ethylene carbonate (EC) to dimethyl carbonate (DMC) by using catalytic reactive distillation (RD) is a promising approach for carbon dioxide utilization. However, there is still scarcity of comprehensive comparison between the two RD processes. Hence, using the UNIQUAC model and kinetics calibrated by literature and our experiments, we conduct an extensive comparison of the two RD processes. Based on the kinetic insights, laboratory RD processes for both reactions are modeled, analyzed, and experimentally validated. Consequently, two RD processes designed to produce 60 ktpy of DMC are optimized and compared. The interplay and control factors between reaction and separation are elucidated and clarified via investigating variations of the actual chemical equilibrium constant profile compared with theoretical values along the reactive section at various pressures, liquid holdups, etc. The results reveal that the optimized EC RD process achieves almost 50 % reductions in both total annual cost and carbon dioxide emission compared to the PC RD process. This work facilitates the carbon neutrality and provides an essential guide for quantitatively assessing the two routes.

Mechanistic study on 4, 4'-sulfonylbis removal with CO2/Ar gas-liquid DBD plasma

In this study, a single dielectric barrier discharge (DBD) coaxial reactor was used to degrade 4, 4'-sulfonylbis (TBBPS) in water using greenhouse gas (CO2) and argon as the carrier gases. The investigation focused on CO2 conversion, reactive species formation, gas-liquid mass transfer mechanism, and degradation mechanism of TBBPS during the discharge plasma process. With the decrease of CO2/Ar ratio in the process of plasma discharge, the emission spectrum intensity of Ar, CO2 and excited reactive species was enhanced. This increase promoted collision and dissociation of CO2, resulting in a series of chemical reactions that improved the production of reactive species such as ·OH, 1O2, H2O2 and O3. These reactive species initiated a sequence of reactions with TBBPS. Results indicated that at a gas flow rate of 240 mL/min with a CO2/Ar ratio of 1:5, both the highest CO2 conversion rate (17.76%) and TBBPS degradation rate (94.24%) were achieved. The degradation mechanism was elucidated by determining types and contents of reactive species present in treatment liquid along with analysis of intermediate products using liquid chromatography-mass spectrometry techniques. This research provides novel insights into carbon dioxide utilization and water pollution control through dielectric barrier discharge plasma technology.

Sustainable repurpose of waste melamine foam into bifunctional catalysts for efficient CO2 capture and conversion

Global climate change has driven the scientific community to improve the utilization of a critical C1 resource carbon dioxide (CO2) through carbon capture utilization (CCU) technology. The cycloaddition of CO2 with epoxides provides perfect atom economy and economic feasibility to produce versatile cyclic carbonates used in various industries. However, the stable nature of CO2 and epoxides requires highly active catalysts. In this work, the repurpose of nitrogenous waste melamine foams (MFs) as high-performance catalysts for the cycloaddition of CO2 was explored. The pyrolyzed MF was modified with Cu to prepare a series of acid-base bifunctional porous catalysts (MFC-X-Cu). The results demonstrate that the acid-base synergy of the MFC-X-Cu catalysts increases the efficiency of the cycloaddition of various epoxides, yielding target products at 96–99% under mild conditions. Moreover, the characterization results revealed that the superior performance of MFC-X-Cu stems from its hollow structure and acid-base synergy, which are derived from nitrogen species in the repurposed MF and the post-modified copper component. The catalyst maintained consistent catalytic efficiency over five cycles, highlighting its strong recyclability. This work presents an eco-friendly and sustainable approach towards carbon neutrality by utilizing modified waste materials for CO2 conversion into high-value chemicals.