Reactions Of Carbon Research Articles

Land suitability assessment for improved land use planning in selected watersheds of Haryana

Aim: The current study aimed to evaluate the capacity and suitability of land for semi-arid region of Haryana in selected watersheds to identify the major limitations of crop production. Methodology: The study was carried out in Bhiwani district of Haryana in 2017 where eight typical pedons (P) representing four micro-watersheds viz., Motipura (P1 and P2), Sainiwas (P3 and P4), Jhumpa (P5 and P6), Budhsheli (P7 and P8) were studied. Results: The studied pedons were neutral to alkaline in reaction (pH 6.87-9.10), non-saline (EC 0.02-0.21 dS m-1) and low in organic carbon (OC) (0.06-0.27%). Available N, P, K and S were low (42.00-189.00 kg ha-1), low to medium (4.20-17.10 kg ha-1), low to high (62.20-326.50 kg ha-1) and low (0.40-19.20 mg kg-1) in the studied pedons, respectively. Soils were deficient in available Fe and Zn but marginal to sufficient in available Mn and Cu. Interpretation: Soils were classified as IIsf and IIItsf and S3s and N1s according to LCC and irrigation suitability, respectively. The pedons were found suitable (S1) to moderately suitable (S2) for guar (cluster bean), oilseeds (mustard), moderately suitable (S2) to marginally suitable (S3) for pearl millet, gram and forestry, and marginally suitable (S3) for cotton and wheat. Key words: Land suitability, Nutrients, Pedon, Semiarid, Watershed

Synergistic carbon and hydrogen reactions in the electrochemical reduction of CO2to liquid fuels

This review summarises the strategies of designing electrocatalysts to improve both carbon reaction (CO2to carbon intermediates and to organic liquid fuels) and hydrogen reaction (hydrogenation of carbon intermediates), and electrochemical reduction of CO2to liquid fuels.

Kinetics of Oxygen Transfer Reactions on the Graphene Surface. Part III. H <sub>2</sub>O vs. CO <sub>2</sub>, Mechanistic Comparisons Between Armchair And Zigzag Sites.

Reactions of carbon and oxygen containing molecules are ubiquitous on earth and the universe. Through ab initio calculations, we study the reactions of H2O and CO2 with small graphene clusters using armchair edges, both H- and non-H terminated, and compare with studies of zigzag carbon edges interacting with oxygen-containing molecules such as O2, NO, H2O and CO2. Our results highlight the differences between armchair and zigzag sites and our mechanistic comparisons regarding carbon reactions with H2O and CO2, identify similarities and differences on their reactivity. In the case of H2O, adsorption is favored over armchair sites exhibiting no rotational process and the H2 desorption step is favored over zigzag sites. Regarding the CO2 reaction, chemisorption is favored on zigzag sites. Several adsorption mechanisms lead to the formation of lactone groups as the most stable structures. A specific armchair CO desorption path for stable functional groups exists, agreeing with experimental reports, and thus completing our explanations for this reaction, previously limited to zigzag sites. Finally, the reaction over armchair sites leads to direct formation of pentagonal rings, without an active site deactivation process and with low activation energies. This deeper understanding provides further possibilities for improving the control of carbon-oxygen reactions.

Non-isothermal effectiveness factors in thermo-chemical char conversion

Modeling heterogeneous combustion and gasification at large or industry scale is important in ongoing research and development activities. These simulations rely on comprehensive, accurate, and efficient solid conversion models. Pore diffusion is an important sub-process of gas–solid reactions and is often approximated by effectiveness factors. Analytic expressions for isothermal effectiveness factors are usually used, due to the numerical effort of determining non-isothermal ones. The consequences of this simplification are evaluated by determining non-isothermal effectiveness factors for typical combustion conditions for the reactions of carbon with O2,CO2,H2O, and H2. The results show that exothermal reaction rates are under-estimated, while endothermal are over-estimated at low and intermediate temperatures for Thiele moduli between 0.1 and 100. In addition, the reaction zone relocates towards the outer particle layers under these conditions. Cross-sensitivity effects between the four reactions are neglected in this study. A reasonable approximation is the superposition of the individual reactions, because the oxidation reaction is dominant under typical combustion conditions.

Dark Iron-Catalyzed Reactions in Acidic and Viscous Aerosol Systems Efficiently Form Secondary Brown Carbon.

Iron-driven secondary brown carbon formation reactions from water-soluble organics in cloud droplets and aerosols create insoluble and soluble products of emerging atmospheric importance. This work shows, for the first time, results on dark iron-catalyzed polymerization of catechol forming insoluble black polycatechol particles and colored water-soluble oligomers under conditions characteristic of viscous multicomponent aerosol systems with relatively high ionic strength (I = 1-12 m) and acidic pH (∼2). These systems contain ammonium sulfate (AS)/nitrate (AN) and C3-C5 dicarboxylic acids, namely, malonic, malic, succinic, and glutaric acids. Using dynamic light scattering (DLS) and ultra high pressure liquid chromatography-mass spectrometry (UHPLC-MS), we show results on the rate of particle growth/agglomeration and identity of soluble oligomeric reaction products. We found that increasing I above 1 m and adding diacids with oxygen-to-carbon molar ratio (O:C > 1) significantly reduced the rate of polycatechol formation/aggregation by a factor of 1.3 ± 0.4 in AS solution in the first 60 min of reaction time. Using AN, rates were too slow to be quantified using DLS, but particles formed after 24 h reaction time. These results were explained by the relative concentration and affinity of ligands to Fe(III). We also report detectable amounts of soluble and colored oligomers in reactions with a slow rate of polycatechol formation, including organonitrogen compounds. These results highlight that brown carbon formation from iron chemistry is efficient under a wide range of aerosol physical states and chemical composition.

Metal Flux Growth of Praseodymium Iron Carbides Featuring FeC3 Units

Reactions of iron and carbon in a Pr/Ni eutectic flux have yielded three new Pr/Fe/C carbometalate compounds. Pr14Fe6C13 forms in tetragonal space group P42/mnm; Pr26Fe19C29 forms in orthorhombic s...

High‐throughput gas chromatographic analysis of soluble carbon content in tobacco‐related products enabled by phase‐conversion reaction

AbstractThis study demonstrated a simple and efficient method for quantifying soluble carbon content in tobacco‐related products using a reaction chromatographic technique. This approach was based on the measurement of the carbon dioxide generated from the oxidation reaction of soluble carbons (i.e., five‐carbon and six‐carbon sugars) in tobacco‐related sample with potassium dichromate in the presence of sulfuric acid, in which soluble carbons were oxidized to carbon dioxide (at 95°C for 40 min). After that, the carbon dioxide was analyzed by gas chromatography. The data illustrated that the proposed approach was precise (RSD < 3.19%) and accurate (relative differences < 9.52%), and the recoveries ranged from 97.9 to 102.3%. The present technique is sensitive, efficient, and could be a potential alternative for the high‐throughput analysis of the soluble carbon content of tobacco‐related products in both laboratory and industrial applications.

Nickel-Catalyzed Reductive Allylation of Aldehydes with Allyl Acetates

AbstractCarbonyl allylation reactions constitute an important step in the formation of carbon–carbon reactions, and involve various related reactions that chiefly use allylmetal reagents. This report presents a nickel-catalyzed carbonyl allylation reaction using allyl acetate, which produces homoallyl alcohols in moderate to good yields, as an efficient methodology under reductive coupling conditions.

On the Covariation of Chlorophyll Fluorescence and Photosynthesis Across Scales

AbstractRecent advances in remote sensing of solar‐induced chlorophyll fluorescence (SIF) have garnered wide interest from the biogeoscience and Earth system science communities, due to the observed linearity between SIF and gross primary productivity (GPP) at increasing spatiotemporal scales. Three recent studies, Maguire et al., (2020, https://doi.org/10.1029/2020GL087858), He et al. (2020, https://doi.org/10.1029/2020GL087474), and Marrs et al. (2020, https://doi.org/10.1029/2020GL087956) highlight a nonlinear relationship between fluorescence and photochemical yields and show empirical evidence for the decoupling of SIF, stomata, and the carbon reactions of photosynthesis. Such mechanistic studies help advance our understanding of what SIF is and what it is not. We argue that these findings are not necessarily contradictory to the linear SIF‐GPP relationship observed at the satellite scale and provide context for where, when, and why fluorescence and photosynthesis diverge at smaller spatiotemporal scales. Understanding scale dependencies of remote sensing data is crucial for interpreting SIF as a proxy for GPP.

The carbon reactions of photosynthesis: role of lectins and glycoregulation

Modulation of glycoregulation in agriculture is reviewed here with emphasis on the elucidation of previously unknown pathways involving vacuolar lectins as well as a bypass of lectins that direct free sugars toward productivity. The reversible binding sequences of the endogenous lectin cycle are compared to an induced lectin bypass, as follows. (1) In the cycle, carbohydrate ligands, with similar binding specificities that compete for binding sites on lectins, are involved in the natural cycle of sugar exchanges. (2) For the bypass, tightly bound ligands that occupy lectins prevent free sugars from binding, making them available for productivity. This bypass is induced by methyl-α-D-mannopyranoside, a biochemical plant growth regulator for photosynthesis. Integration of this novel technology, with structural elements crucial for ligand binding by the lectins and with nitrogen assimilation, provides the basis for successful modulation of glycoregulation in crops for enhancement of quality and quantity.

Service life of GGBFS concrete under carbonation through probabilistic method considering cold joint and tensile stress

Carbonation is a typical deterioration phenomenon which accelerates steel corrosion through pH drop in pore water by intrusion of external carbon dioxide (CO2). Many researches have been performed on carbonation process considering carbonic reaction, mixture conditions, and exterior conditions. Recently probabilistic approaches have been adopted for considering engineering uncertainties such as complicated material behavior, simple evaluation system, and limited sample numbers. In the study, the service life variation was evaluated considering several effects of induced tensile stress level, cold joint, and GGBFS (Ground Granulated Blast Furnace Slag) through probabilistic approach. Utilizing the previous test results, the effect of loading conditions on carbonation depth was investigated. Four design parameters like cover depth, exterior CO2 concentration, carbonatable material, and CO2 diffusion coefficient were assumed as random variables for probability analysis. Through MCS (Monte Carlo Simulation) with normal distributions and intended PDF (Probability of Durability Failure) of 10%, variations of service life were simulated for the RC structure under loading conditions. The effects of COVs (Coefficient of Variation) for design parameters were also simulated. The comparisons of the predicted service life from the probabilistic and deterministic methods were quantitatively discussed, and the safety index with service life was also investigated. The results of this study can provide useful information on maintenance priority and service life evaluation for RC structures containing cold joint subjected to tensile stress.

Frontispiece: New Visible‐Light‐Triggered Photocatalytic Trifluoromethylation Reactions of Carbon–Carbon Multiple Bonds and (Hetero)Aromatic Compounds

Frontispiece: New Visible‐Light‐Triggered Photocatalytic Trifluoromethylation Reactions of Carbon–Carbon Multiple Bonds and (Hetero)Aromatic Compounds

Large-scale Proteomic and Phosphoproteomic Analyses of Maize Seedling Leaves During De-etiolation

De-etiolation consists of a series of developmental and physiological changes that a plant undergoes in response to light. During this process light, an important environmental signal, triggers the inhibition of mesocotyl elongation and the production of photosynthetically active chloroplasts, and etiolated leaves transition from the “sink” stage to the “source” stage. De-etiolation has been extensively studied in maize (Zea mays L.). However, little is known about how this transition is regulated. In this study, we described a quantitative proteomic and phosphoproteomic atlas of the de-etiolation process in maize. We identified 16,420 proteins in proteome, among which 14,168 proteins were quantified. In addition, 8746 phosphorylation sites within 3110 proteins were identified. From the combined proteomic and phosphoproteomic data, we identified a total of 17,436 proteins. Only 7.0% (998/14,168) of proteins significantly changed in abundance during de-etiolation. In contrast, 26.6% of phosphorylated proteins exhibited significant changes in phosphorylation level; these included proteins involved in gene expression and homeostatic pathways and rate-limiting enzymes involved in photosynthetic light and carbon reactions. Based on phosphoproteomic analysis, 34.0% (1057/3110) of phosphorylated proteins identified in this study contained more than 2 phosphorylation sites, and 37 proteins contained more than 16 phosphorylation sites, indicating that multi-phosphorylation is ubiquitous during the de-etiolation process. Our results suggest that plants might preferentially regulate the level of posttranslational modifications (PTMs) rather than protein abundance for adapting to changing environments. The study of PTMs could thus better reveal the regulation of de-etiolation.

New Visible‐Light‐Triggered Photocatalytic Trifluoromethylation Reactions of Carbon–Carbon Multiple Bonds and (Hetero)Aromatic Compounds

Visible-light-photocatalyzed methods employed in synthetic transformations present attractive properties such as environmentally friendly, safety, availability and excellent functional group tolerance. In this regard, research on the visible-light photocatalytic incorporation of the trifluoromethyl CF3 moiety into organic substrates, in particular, has contributed to a clear evolution of the field of photocatalysis. Although this particular area is constantly evolving and has been reviewed, the last five years have experienced an outburst of seminal and significant photocatalytic trifluoromethylation examples that are leading the way and opening new synthetic avenues. Recent review articles on Ru- and Ir-based photocatalytic trifluoromethylation reactions have borne witness of this evolution. Although this account will show the new Ru- and Ir-based photocatalytic trifluoromethylations, Sections 2 and 3 will also illustrate other photocatalytic systems, such as organic dyes, organic semiconductors and newly-developed all-organic photocatalysts. All the known and reviewed strategies for photocatalytic trifluoromethylation reactions of olefins and (hetero)aromatic compounds will not be discussed but will be summarized in two figures (Figures 4 and 5), and new examples (2015-present) will be presented and discussed.

New Measurement of ^{12}C+^{12}C Fusion Reaction at Astrophysical Energies.

Carbon and oxygen burning reactions, in particular, ^{12}C+^{12}C fusion, are important for the understanding and interpretation of the late phases of stellar evolution as well as the ignition and nucleosynthesis in cataclysmic binary systems such as type Ia supernovae and x-ray superbursts. A new measurement of this reaction has been performed at the University of Notre Dame using particle-γ coincidence techniques with SAND (a silicon detector array) at the high-intensity 5U Pelletron accelerator. New results for ^{12}C+^{12}C fusion at low energies relevant to nuclear astrophysics are reported. They show strong disagreement with a recent measurement using the indirect Trojan Horse method. The impact on the carbon burning process under astrophysical scenarios will be discussed.

Using the Secondary PH/BH Functional Groups of an Active Geminal Frustrated Lewis Pair for Carbon Monoxide Reduction and Reactions with Nitriles and Isonitriles

AbstractReaction of the secondary alkynyl(Mes*)PH phosphane 2 with (Fmes)BH2⋅SMe2 gives the geminal PH/BH frustrated Lewis pair (FLP) 3. The PH and the BH functions are jointly used in the reduction of carbon monoxide under mild reaction conditions to give the [P]‐CH2‐O‐[B] product. A subsequent cycloaddition sequence results in the liberation of formaldehyde. The FLP 3 reacts with benzonitrile to give a P‐benzamidine, and it couples two isonitriles at the FLP framework.

Using the Secondary PH/BH Functional Groups of an Active Geminal Frustrated Lewis Pair for Carbon Monoxide Reduction and Reactions with Nitriles and Isonitriles.

Reaction of the secondary alkynyl(Mes*)PH phosphane 2 with (Fmes)BH2 ⋅SMe2 gives the geminal PH/BH frustrated Lewis pair (FLP) 3. The PH and the BH functions are jointly used in the reduction of carbon monoxide under mild reaction conditions to give the [P]-CH2 -O-[B] product. A subsequent cycloaddition sequence results in the liberation of formaldehyde. The FLP 3 reacts with benzonitrile to give a P-benzamidine, and it couples two isonitriles at the FLP framework.

Hydrogenation reactions of carbon on Earth: Linking methane, margarine, and life

AbstractHydrogenation reactions are a major route of electron and proton flow on Earth. Interfacing geology and organic chemistry, hydrogenations occupy pivotal points in the Earth’s global geochemical cycles. Some examples of hydrogenation reactions on Earth today include the production and consumption of methane in both abiotic and biotic reactions, the reduction of protons in hydrothermal settings, and the biological synthesis and degradation of fatty acids. Hydrogenation reactions were likely important for prebiotic chemistry on the early Earth, and today serve as one of the fundamental reaction classes that enable cellular life to construct biomolecules. An understanding and awareness of hydrogenation reactions is helpful for comprehending the larger web of molecular and material inter-conversions on our planet. In this brief review we detail some important hydrogenation and dehydrogenation reactions as they relate to geology, biology, industry, and atmospheric chemistry. Such reactions have implications ranging from the suite of reactions on early Earth to industrial applications like the production of hydrocarbon fuel.

Assessing the sources of inorganic carbon in surface-, soil- and non-thermal groundwater in Iceland by δ13C and 14C

Chemical weathering and associated atmospheric CO2 uptake by surface water and transport of dissolved inorganic carbon (DIC) by rivers to the ocean and subsequent carbonate deposition has been suggested to play a major role in long-time climate changes. However, DIC in surface-, soil- and groundwater may also be sourced from decomposition of organic matter, direct leaching of carbon from the rocks themselves and deep degassing in volcanic areas and modified by chemical reactions. Carbon isotopes (δ13C and 14C) of surface-, soil-, and non-thermal groundwater in Iceland were studied to assess the various sources and reactions of carbon, atmospheric CO2 uptake upon basalt weathering, and water apparent radiocarbon age. The waters had a pH of ∼6.5–10.9, dissolved inorganic carbon (DIC) of 3.2–194 ppm, and were of meteoric origin based on the δD and δ18O content. The measured range of δ13CDIC and 14CDIC in the waters was large, −25.9 to +2.2‰ (average −8.2‰, n = 334) and 7.9–126 pMC (average 95 pMC, n = 334), respectively. Insignificant annual and seasonal variations in DIC and isotope composition were generally observed for a given location. Applying isotope modeling and comparing the results with the dataset revealed three major sources of DIC: (1) leaching of carbon from basaltic rocks, (2) atmospheric CO2(g) through water-air exchange at the surface, and (3) decomposition of organic matter in soils. The majority of DIC originated from atmospheric CO2(g) (15–100%, av. 64%) and decomposition of organic matter (0–85%, av. 34%) with the highest values observed for soil waters. Carbon from rock leaching was generally insignificant (av. 2%) except for some groundwater (3–100%). The atmospheric CO2 uptake by basalt weathering for selected rivers in East Iceland was assessed to be 0.09–1.56 mol/km2/yr or ∼5–40% (av. 17%) lower than total riverine CO2 fluxes suggest.

Silver(II) and Silver(III) Intermediates in Alkene Aziridination with a Dinuclear Silver(I) Nitrene Transfer Catalyst

In recent years, synthetically useful homogeneous catalysis has been developed with silver, including nitrene transfer reactions for carbon–nitrogen bond formation. However, the mechanisms of silve...