Atmospheric Pressure Of Carbon Dioxide Research Articles

Monodentate H-bond donor bifunctional catalyst in fixation of atmospheric pressure carbon dioxide into cyclic carbonates

The efficient conversion of epoxides and CO2 into cyclic carbonates by employing H-bond donor (HBD) and nucleophilic halide cooperating catalysis under mild conditions is an attractive research topic. Herein, we report a new onium halide bearing a CON(H) moiety as a weak HBD catalyst to facilitate the cycloaddition reaction of epoxides and CO2 under mild conditions. The structural influences on the catalytic activity were scrutinized, which included tunable substituents, the distance between functional groups, and counter anions. The result indicated that the catalyst of the bis-meta-substitutions on an aromatic ring exhibited excellent activity for converting epichlorohydrin into cyclic carbonate under atmospheric pressure at 25–70 °C. Twelve terminal epoxides were converted into corresponding cyclic carbonates in 72–99 % isolated yield. A reasonable activation mechanism was proposed and validated by using control experiments and NMR titrations. In addition, the good recyclability proves that the onium halide is a sustainable green organocatalyst.

Acidificação oceânica: uma questão negligenciada

Oceans play a crucial role in many natural processes, such as oxygen production and climate regulation. Ocean acidification (OA) is a phenomenon caused, among other factors, by the dissolution of certain gases in water, such as carbon dioxide (CO2). It is estimated that by 2100, the partial atmospheric pressure of carbon dioxide (pCO2) will double from pre-industrial levels, aggravating this process. The negative consequences of OA are not yet fully understood, in part due to the limitations of laboratory experiments. However, it is known that they include increased concentrations of CO2 in the atmosphere, structural and functional modifications of ecosystems, changes in richness, diversity and geographic distribution of species, impairment of ecosystem goods and services, and commercial activities, such as fishing and aquaculture, as well as global warming. OA, in principle, is considered irreversible, as it depends on the reduction of emissions of the gases involved in the process, especially CO2, and the slow natural process of neutralization. However, some mitigation measures, allied with adaptation measures, can mitigate the effects of OA. These and other issues related to ocean vulnerability caused by climate change will be raised in this review.

Fe(III)-Anchored Porphyrin-Based Nanoporous Covalent Organic Frameworks for Green Synthesis of Cyclic Carbonates from Olefins and CO2 under Atmospheric Pressure Conditions.

The utilization of carbon dioxide (CO2) as a C1 source coupled with olefins, readily accessible feedstocks, offers dual advantages of mitigating atmospheric carbon dioxide and green synthesis of valuable chemicals. In this regard, herein we demonstrate the application of Fe(III)-anchored porphyrin-based covalent organic framework (P-COF) as a promising recyclable catalyst for one-step generation of cyclic carbonates (CCs), value-added commodity chemicals from olefins and CO2, under mild atmospheric pressure conditions. Moreover, this one-pot synthesis was applied to transform various olefins (aliphatic and aromatic) into the corresponding CCs in good yield and selectivity. In addition, the Fe(III)@P-COF showed good recyclability and durability for multiple reuse cycles without losing its catalytic activity. Notably, this one-step synthesis strategy presents an eco-friendly, atom-economic alternative to the conventional two-step process requiring epoxides. This work represents a rare demonstration of porphyrin COF-catalyzed one-pot CC synthesis by utilizing readily available olefins at atmospheric pressure of carbon dioxide.

A Dual-Purpose Ce(III)-Organic Framework with Amine Groups and Open Metal Sites: Third-Order Nonlinear Optical Activity and Catalytic CO2 Fixation.

The present work focuses on the synthesis and properties of a novel multifunctional cerium(III) MOF, [Ce2(data)3(DMF)4]·DMF (data2-: 2,5-diaminoterephthalate), abbreviated as NH2-Ce-MUM-2. Its crystal structure reveals an intricate 3D 4,5-connected framework with a xah topology. This MOF features unique properties, such as open metal sites, presence of free amino groups, and high stability. Two main applications of NH2-Ce-MUM-2 were investigated: (i) as a heterogeneous catalyst in the CO2 fixation into cyclic carbonates and (ii) as a material with third-order nonlinear optical activity. As a model reaction, the cycloaddition of CO2 to propylene oxide to give the corresponding cyclic carbonate was explored under mild conditions, at the atmospheric pressure of carbon dioxide and in the absence of cocatalyst and added solvent. Various reaction parameters were investigated toward optimization and exploration of substrate scope, revealing up to 99% product yields of cyclic carbonate products. Besides, the structure of NH2-Ce-MUM-2 is highly stable, permitting its recyclability and reusability in further catalytic experiments. The significant contributions of free amino groups and open metal sites within this catalyst were particularly considered when proposing a potential mechanism for the reaction. Z-Scan measurements were used to evaluate the nonlinear optical (NLO) properties of NH2-Ce-MUM-2 at various laser intensities. A high two-photon absorption (TPA) under greater incident intensities shows that NH2-Ce-MUM-2 might be applicable in optical switching devices. Besides, the self-focusing effects of NH2-Ce-MUM-2 under various incident intensities were highlighted by the nonlinear index of refraction (n2). By reporting the synthesis and characterization of a novel MOF, along with its highly promising catalytic and NLO behavior, the current study introduces an additional example of multifunctional material into a growing family of metal-organic frameworks.

Effects of elevated pCO2 on the physiological energetics of Pacific oyster, Crassostrea gigas

Abstract Ocean acidification is predicted to have significant implications for marine calcifying organisms. However, little is known about the physiological responses of Pacific oyster, Crassostrea gigas, to elevated partial pressure of atmospheric carbon dioxide (pCO2) under natural fluctuations associated with a farm environment. The present study evaluated the effect of two pCO2 levels (i.e. ambient ∼625 μatm and elevated ∼1432 μatm) on the physiological processes and growth of C. gigas in in situ mesocosms that simulated the farm environment. Oysters were exposed for 30 days over a sensitive period during their production cycle when they are first exposed to natural coastal conditions. Despite this being a well-known “bottleneck” in production, it remains understudied with respect to climate change. Results showed that elevated pCO2 levels decreased clearance rate, ingestion rate, absorption efficiency, and oxygen to nitrogen ratio, while increasing oxygen consumption and ammonia-N excretion rates. These physiological responses of oysters resulted in a reduction in energy available for growth (scope for growth). No mortality was observed in the control or elevated pCO2 treatments, indicating that although oyster may survive future coastal acidification, the allocation of energy towards production within aquaculture systems will decrease in the future, affecting the culture of these economically important marine bivalves.

Switchable synthesis of cyclic carbamates by carbon dioxide fixation at atmospheric pressure.

The base-promoted switchable synthesis of five- and six-membered cyclic carbamates using atmospheric pressure carbon dioxide as the C1 source was developed. The chemoselectivity of products was simply controlled by changing bases and solvents. The reaction proceeds effectively under mild conditions, affording valuable cyclic carbamates. Experimental results and DFT studies revealed the reaction mechanism.

AIR-SEA FLUX OF CO2 IN THE WATERS OF KARIMUNJAWA ISLAND, INDONESIA

The purpose of this study was to determine the distribution of CO2 flux in Karimunjawa in the east monsoon. The variables in this study were temperature; pH; salinity; DO; CO2 atm was measured using a CO2 meter; chlorophyll-a, phosphate, silicate were measured spectrophotometric method. Total Alkalinity / TA was measured using the titration method with the principle of changing pH; DIC (Dissolved Inorganic Carbon) was measured using CO2sys software. The partial pressure of seawater carbon dioxide calculated using formula: pCO2sea = 6.31T2 + 61,9 Chla2 – 365.85T – 94.41 Chl-a +5715.94, the partial pressure of atmospheric carbon dioxide calculated using formula: pCO2atm = xCO2atm (pb - pH2O). The calculation of the estimated CO2 flux using the formula: Flux CO2 = Kh x kwa x (∆pCO2) , if the CO2 flux has a positive value water acts as a CO2 source, and if it is negative, the waters act as a CO2 sink.. CO2 flux in Karimunjawa waters during east monsoon (represented by August 2018) showed that in Karimunjawa waters with normal pH 7.2-7.4 were dominated by bicarbonate ion HCO3-with an average value of DIC 1847.24 µmol/kg dan TA 1912.51 µmol/kg. The partial pressure of seawater CO2 is higher than the partial pressure of atmospheric CO2 this indicates that the role of Karimunjawa waters as a source of CO2 where there is release of carbon dioxide into the atmosphere with CO2 flux values ranging from 8.549 – 13.272 mmol m-2 day-1. The variables that affect the flux of CO2 were the pCO2sea and ΔpCO2 with a very strong and positive correlation. These two variables were influenced by sea water temperature, salinity, chlorophyll-a, phosphate and silicate.

Extended Pummerer fragmentation mediated by carbon dioxide and cyanide

Pummerer rearrangement reactions generate sulfur (II) oxidation state from sulfur (IV) starting materials in the presence of activating reagents. We found unprecedented transformation of vinyl sulfoxide; disulfide formation reactions mediated by atmospheric pressure of carbon dioxide in extended Pummerer rearrangement reactions. Only under CO 2 atmosphere, we observed moderate to high yields of disulfide starting from sulfur (IV) starting materials. Investigations on the reaction mechanism revealed that the degradation of the starting materials and the products was significant in the absence of CO 2 . Further evidence for the suggested reaction mechanism was obtained by a cross-over experiment and a radical trapping reagent.

Engineering pore morphology using silica template route over mesoporous cobalt oxide and its implications in atmospheric pressure carbon dioxide hydrogenation to olefins

Highly ordered mesoporous cobalt oxides (denoted as m-Co-KIT-6 and m-Co-SBA-15) with three dimensional and two dimensional pore morphology respectively have been synthesized using 3D KIT-6, and 2D SBA-15 as silica template via nanocasting route. CO2 hydrogenation activity was evaluated for these mesoporous materials under atmospheric pressure conditions. In comparison to nanoparticles of cobalt oxide (Co3O4-nano), mesoporous catalysts showed excellent activity for CO2 hydrogenation due to their higher number of exposed active sites and lower mass diffusion limitations. The ordered mesoporous structure of Co3O4 catalysts favored the chain growth of carbon atoms for the production of C2+ hydrocarbons while Co3O4 nanoparticles showed strong selectivity toward CH4. High selectivity for C2+ (∼ 25%) was obtained for both m-Co-KIT-6 and m-Co-SBA-15 catalysts at 320 °C. In addition, the 3D pore structure of m-Co-KIT-6 catalyst exclusively formed more olefins (54.9%) fraction.

Silver Nanoparticles Architectured HMP as a Recyclable Catalyst for Tetramic Acid and Propiolic Acid Synthesis through CO2 Capture at Atmospheric Pressure

AbstractThe recent advancement on the tailored synthesis of hypercrosslinked microporous polymer (HMP‐2) has assembled significant concentration by the virtue of its adjustable porosity, operative design and absolutely ordering structure. This perfectly structured Ag NPs supported carbocatalyst (Ag‐HMP‐2) has been synthesized by Friedel‐Crafts alkylation between 4,4′‐Bis(bromomethyl)‐1,1′‐biphenyl and carbazole over anhydrous iron(III)chloride catalysis followed by the appending of the silver nanoparticles (Ag NPs) onto the material. The silver nanoparticle was decorated over the HMP‐2 to prepare the corresponding catalyst (Ag‐HMP‐2). The characterization of the newly produced material has been conducted by N2 adsorption/desorption studies, XPS, FE‐SEM, transmission electron microscopy (TEM) and Powder X‐ray diffraction (PXRD) methods. This microporous catalyst has spectacular activities for the production of tetramic acids from various types of propargylic amine derivatives at 60 °C under atmospheric carbon dioxide pressure. Parallel attempt on fixation of CO2 was executed over terminal alkynes to synthesize propiolic acids under 1 atm pressure. The catalyst (Ag‐HMP‐2) exhibited sufficient recycling ability for the generation of tetramic acids and propiolic acids up to five catalytic runs without reduction in its catalytic activity.

Design and characterization of a solar-enhanced microwave plasma reactor for atmospheric pressure carbon dioxide decomposition

The decomposition of carbon dioxide (CO2) is a primary step in carbon re-utilization approaches aimed to fulfill fuels and chemicals demands and mitigate environmental emissions. Plasmachemical CO2 decomposition processes can be highly efficient; however, their reliance on electrical energy can limit their economic viability and sustainability advantage. In contrast, solar thermochemical CO2 decomposition approaches can have limited efficiency, but their direct use of the most abundant form of renewable energy affords them the greatest sustainability potential. Solar-enhanced microwave plasma (SEMP) chemical synthesis, based on the direct interaction between microwave plasma and concentrated solar radiation, is investigated as a novel approach to combine the advantages of plasmachemical and solar thermochemical processes. SEMP is motivated by the potential for synergistic effects between solar photons and plasma species, implied by the markedly greater spectral absorption of nonequilibrium CO2 plasma compared to that of equilibrium CO2, to lead to enhanced chemical decomposition. The design, development, and characterization of a SEMP reactor for atmospheric pressure CO2 decomposition is presented. The reactor is powered by a 1.25 kW magnetron and by up to 525 W of incident radiative power from a high-flux solar simulator. Experimental results reveal that the microwave plasma absorbs up to 20% of concentrated solar radiation at a solar-to-electrical power ratio of 0.5, and that relative absorption decreases with increasing solar input power. However, conversion efficiency and plasma energy efficiency increase with increasing solar power, up to 9% and 25% respectively, for a solar-to-electrical power ratio of 0.75. The enhanced process performance appears to be a consequence of the greater power density in the plasma caused by the direct absorption of solar radiation.

Optically pumped gas terahertz fiber laser based on gold-coated quartz hollow-core fiber.

An optically pumped gas terahertz fiber laser based on gold-coated quartz hollow-core fiber is demonstrated. When the terahertz fiber laser is filled with methanol gas and pumped by a piezoelectric-ceramic-transducer-adjusted transversely excited atmospheric pressure carbon dioxide laser, a continuous 2.52THz laser with the output power of 110mW is obtained. Attributed to the adjustment of the piezoelectric ceramic transducer in the carbon dioxide laser, the fluctuation of the terahertz fiber laser output power is controlled within ±5%. The result confirms the possibility of a compact flexible optically pumped gas terahertz fiber laser.

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

Ag NPs decorated on a COF in the presence of DBU as an efficient catalytic system for the synthesis of tetramic acids via CO2 fixation into propargylic amines at atmospheric pressure.

CO2 fixation reactions by inserting it in reactive organic compounds are very challenging for the utilization of this abundant and harmful gas present in air and thus to mitigate this greenhouse gas responsible for global warming. This can be achieved by appropriate design of functionalized porous nanocatalysts having high surface areas and porosity and good CO2 uptake capacity. Herein, we first report the decoration of silver nanoparticles (NPs) over the surface of a covalent organic framework (COF) material TpPa-1 synthesized through the polycondensation of 2,4,6-triformylphloroglucinol (TFP) and p-phenylenediamine. The resulting material Ag@TpPa-1 was thoroughly characterized by N2 adsorption/desorption, powder X-ray diffraction (PXRD), FE-SEM, TEM, UV-Vis, FT IR and thermogravimetric techniques. This Ag NP decorated porous COF in the presence of DBU exhibited excellent catalytic activity for the synthesis of tetramic acids from a variety of propargylic amine derivatives at 60 °C under atmospheric pressure of carbon dioxide via formation of oxazolidinones, where CO2 acts as a C1 reagent. The Ag@TpPa-1 catalyst exhibited excellent recycling efficiency for the synthesis of tetramic acid with no leaching of Ag from the catalyst surface.

Preliminary Study on Possibility Cl Detection in Soil by Means of The Unique Sub-target in a Transversely Excited Atmospheric Pressure (TEA) Carbon Dioxide (CO2) Laser Induced Breakdown Spectroscopy

A preliminary study on Cl detection in soil sample using LIBS has been carried out. The soil sample was mixed with silicon grease to allow attachment to the surface of a nickel plate acting as a sub-target. The laser used in this work is a TEA CO2 laser that operates at wavelength of 10.6μm with energy and pulse duration of 2.5 J and 200 ns, respectively. The laser beam was focused onto the sample using a zinc selenium lens (f = 200 mm) under air and helium surrounding gas at atmospheric pressure. The emission spectrum from the generated plasma was detected using an optical multichannel analyser (OMA)system consisting of a 0.32-m-focal length spectrograph with a grating of 1200 graves/mm and a 1024-channel photodiode detector array with a micro-channel plate intensifier. Soil sample used in this work is a standard soil sample mixed with NaCl solution at various concentrations. The results show that many emission lines due to salts such as Ca, Mg, Na and K can be detected clearly. Nevertheless, Cl emission line cannot be detected in soil sample, although the sample has been intentionally mixed with Cl, even when Cl content reaching 1000 ppm. It is therefore necessary to develop a new approach to allow LIBS techniques for detecting Cl in soil samples.

Design and characterization of an electromagnetic‐resonant cavity microwave plasma reactor for atmospheric pressure carbon dioxide decomposition

Plasma processes are ideally suited for the conversion of renewable electricity into gas‐phase reactivity, such as for the decomposition of carbon dioxide (CO2). The design, development, and characterization of a microwave plasma reactor for atmospheric pressure undiluted carbon dioxide decomposition are presented. The reactor operates as an electromagnetic‐resonant cavity in which the generated plasma forms a bulb attached to a converging‐diverging nozzle and stabilized by streams of tangentially injected processing gas. Electromagnetic wave confinement, residence time, and critical gas vorticity constitute fundamental reactor sizing and operation parameters. Experimental results show that flow rate plays a dual role in plasma stabilization and process performance, whereas deposited power has a minor role in CO2 decomposition.

Synthesis of Cyclic Carbonates from Epoxides and Carbon Dioxide Catalyzed by MgCl2

Magnesium chloride (MgCl2), a stable and cheap salt, works as an active catalyst for the synthesis of cyclic carbonates from epoxides and atmospheric-pressure carbon dioxide (CO2). Various epoxides are converted to the corresponding cyclic carbonates in good to high yields.

Functionalization and optimization of PLA with coumarin via click chemistry in supercritical CO2

For the first time the functionalization via click chemistry of polylactic acid (PLA) with coumarin in supercritical conditions CO2 has been achieved. Click reaction was performed at atmospheric pressure and supercritical carbon dioxide (scCO2) for comparison being observed that is possible to obtain similar yields, higher than 95% in both cases. Once click functionalization of PLA in scCO2 was achieved the influence of operational conditions on the polymer characteristics and in the yield was studied to get an optimized functionalization process.

Synthesis of benzothiazoles from 2-aminobenzenethiols in the presence of a reusable polythiazolium precatalyst under atmospheric pressure of carbon dioxide

Synthesis of benzothiazoles from 2-aminobenzenethiols and carbon dioxide was carried out using poly(3,4-dimethyl-5-vinylthiazolium) iodide as a precatalyst to in situ generation of NHCs by deprotonation. The reaction was successfully carried out under mild conditions (1 atm of CO2 and 60–70 °C) with a broad substrate scope and functional group tolerance. The precatalyst salt was recovered and reused for several times without any loss of activity.

Carbon Dioxide Oversolubility in Nanoconfined Liquids for the Synthesis of Cyclic Carbonates

AbstractThe physical phenomenon of gas oversolubility in nanoconfined liquids was successfully applied for the catalytic cycloaddition of carbon dioxide to epoxides to generate organic cyclic carbonates. Hybrid adsorbents based on MCM‐41 and SBA‐15 mesoporous silica materials were synthesized, and efficient nucleophile deposition on the surface of the support was achieved through a grafting procedure, which allowed for an effective and durable metal‐free catalytic system. Room‐temperature transformation of styrene and hexene oxides to the corresponding organic carbonates at atmospheric pressure of carbon dioxide was explored.