Oxidation Of Organic Compounds Research Articles

Recent Progress in Situ Application of H2O2 Produced via Catalytic Synthesis.

Industrial production of H2O2 requires lots of energy and causes environmental pollution. Moreover, in subsequent applications, much economic loss could be produced during the transportation process of H2O2 and its dilution process. Therefore, it is highly desirable for in situ application of H2O2. In recent years, catalytic synthesis of H2O2, e. g., direct catalytic synthesis, electrocatalytic synthesis, and photocatalytic synthesis, has attracted more and more attention because the continuous and low-concentration H2O2 produced by catalytic synthesis can be directly used for the oxidation of organic compounds, effectively avoiding the shortcomings of the current industrial route. Here, we briefly reviewed the latest processes for the catalytic production of H2O2 via various routes. On this basis, we summarized and discussed the in situ application of H2O2 in typical organic conversion reactions, including the ammoximation of ketones, the oxidation of alcohols, the oxidation of C-H bonds, and the oxidation of olefins. Some in situ coupling reactions have shown excellent performance with high conversion and selectivity, and the economic cost has been significantly reduced. Finally, the shortcomings of the in situ utilization of H2O2 in coupling reactions were analyzed, and some strategies for promoting the efficiency of the H2O2 application in organic synthesis were proposed.

Bibliometric analysis of photocatalytic oxidation of volatile organic compounds from 1998 to 2023

IntroductionVolatile organic compounds (VOCs) have attracted widespread attention due to their adverse effects on human health. Photocatalytic oxidation is an effective technology for degrading VOCs under ambient conditions.MethodsIn order to better understand the trends and development of global trends in photocatalytic oxidation of VOCs, the analysis of 2493 articles or reviews from the Science Citation Index Expanded (SCIE) in the Web of Science Core Collection, covering the period from 1998 to 2023, was conducted using CiteSpace and VOSviewer software.Results and DiscussionThe findings indicate significant growth in papers concerning photocatalytic oxidation of VOCs. China emerges as the most active country among the main drivers. Principal sources publishing relevant research are Applied Catalysis B-Environmental, Chemical Engineering Journal, Journal of Hazardous Materials, and Environmental Science and Technology. A relatively well-established theoretical framework has been developed for the study of photocatalytic oxidation of VOCs. In the field of VOCs photocatalytic oxidation, the focus is on the development and optimization of advanced photocatalysts with efficient charge separation, better adsorption performance, and a wider light response range. In addition, the in-depth study of the charge generation and transfer mechanisms within the photocatalysts, as well as the comprehensive understanding of the reaction kinetics and catalytic oxidation process, the optimization of the reaction conditions, and the improvement of the catalytic efficiency are at the forefront of the research in this field. This research system is advancing and becoming more refined, with its theoretical propositions, research findings, and methodologies increasingly employed and confirmed.

Combination of Plasma Jet and Magnetron Sputtering─A New Method for Preparing Thin Ni–Co–Mn Oxide Coatings on Stainless Steel Meshes and Their Efficiency in the Total Oxidation of Volatile Organic Compounds

Combination of Plasma Jet and Magnetron Sputtering─A New Method for Preparing Thin Ni–Co–Mn Oxide Coatings on Stainless Steel Meshes and Their Efficiency in the Total Oxidation of Volatile Organic Compounds

Analytical optical methods for measuring organic peroxides and hydroperoxides: An evaluation

Hydrogen peroxide, organic peroxides and hydroperoxides exhibit high reactivity and play a pivotal role in atmospheric chemistry. These compounds are formed during the oxidation of volatile organic compounds in both gaseous and aqueous phases, particularly under low NOx conditions. Their significant contribution to the mass of secondary organic aerosols (SOA) is well-documented, and they are believed to have significant health implications. Several spectrophotometric methods have been employed to measure SOA-bound peroxides in laboratory samples, but systematic comparisons are lacking. In this study, we have assessed the advantages and limitations of these methods, including the traditional and microwave-assisted iodometric methods, the 4-nitrophenyl boronic acid assay (NPBA), and the Fenton reaction-assisted ferrous-xylenol (FOX2) assay. Besides, a comprehensive evaluation of these methodologies was conducted for the first time across a substantial cohort of commercial peroxides and hydroperoxides, employing diverse solvents (namely, water, 1-propanol, acetonitrile, methanol and chloroform) to provide broader insights compared to previous work. Ultimately, the four methods were applied and compared for peroxide determination in laboratory-generated SOA resulting from gas-phase ozonolysis of α-pinene. This study opens new opportunities for future mechanistic investigation into SOA formation and reactivity.

Secondary Organic Aerosol Formation during the Oxidation of Large Aromatic and Other Cyclic Anthropogenic Volatile Organic Compounds.

The secondary organic aerosol (SOA) production from the reactions of anthropogenic large volatile (VOCs) and intermediate volatility organic compounds (IVOCs) with hydroxyl radicals under high NO x conditions was investigated. The organic compounds studied include cyclic alkanes of increasing size (amylcyclohexane, hexylcyclohexane, nonylcyclohexane, and decylcyclohexane) and aromatic compounds (1,3,5-trimethylbenzene, 1,3,5-triethylbenzene and 1,3,5-tritert-butylbenzene). A considerable amount of SOA was formed from all examined compounds. For the studied cyclohexanes (C11-C16) there appears that the SOA yield depends nonlinearly on the length of their substitute chain. The large cyclohexanes had higher yields than the aromatic compounds, but the aromatic precursors produced a more oxidized SOA. This was due to the production of lower volatility and O:C first generation products by the cyclohexanes. Most oxidation products (with C* < 104 μg m-3) in the case of cyclohexanes are SVOCs (∼50%), while of aromatics are IVOCs (∼60%). Structure, molecular size, and length of the substitute chain of the parent hydrocarbon were found to play key roles in SOA formation, oxidation state, and volatility. The SOA volatility distribution, effective vaporization enthalpy, and effective accommodation coefficient were also quantified by combining SOA yields, thermodenuder (TD) and isothermal dilution measurements. Parameterizations for the Volatility Basis Set (VBS) are proposed for future use in chemical transport models.

Metagenomic analysis reveals abundance of mixotrophic, heterotrophic, and homoacetogenic bacteria in a hydrogen-based membrane biofilm reactor

Heterotrophic microorganisms are frequently observed in hydrogenotrophic denitrification systems and are presumed to contribute to their improved performance. However, their roles and metabolic pathways in the hydrogen-based membrane biofilm reactor (H2−MBfR) system remain unclear. The objective of this study was to elucidate the underlying mechanisms driving heterotrophic denitrification. For this purpose, metagenomic analysis was conducted on an H2−MBfR showing higher denitrification performance, focusing on the metabolic function of the microbial community. Functional genes related to H2 oxidation, organic carbon metabolism, and denitrification were the major targets of interest. This analysis revealed a substantial number of genes associated with the oxidation of organic carbon compounds in the biofilm, suggesting its potential for heterotrophic denitrification. Investigation of the genes of interest in metagenome-assembled genomes (MAGs) has demonstrated a predominance of mixotrophs or heterotrophs rather than obligate autotrophs. Notably, MAGs exhibiting the highest abundance of genes of interest were affiliated with Hydrogenophaga and Thauera, implying their significant role in denitrifying the H2−MBfR as mixotrophs utilizing both H2 and organic substrates. The identification of 11 MAGs, presumed to originate from homoacetogens suggested that acetate might contribute to the proliferation of heterotrophs. Based on these metagenomic findings, possible metabolic pathways were identified to explain heterotrophic denitrification within the H2−MBfR biofilms.

Engineering porous clay nanoarchitectures from unusual commercial organoclay: Supported manganese oxide as stable catalysts in the total oxidation of volatile organic compounds

The porous engineering of clay nanoarchitectures (PCN) achieved from a well-known but little-explored commercial organoclay C-20A is reported. Thorough characterizations (by XRD, TGA, N2 sorption, ICP, SEM, TEM, 27Al MAS NMR, DR UV-Vis, XPS, Py-FTIR and H2-TPR) confirmed a delaminated structure presenting a specific surface area of 504 m² g−1, twelve times higher than the sodic montmorillonite used as reference and featuring a new pore system comprising a size range from supermicropores to small mesopores (1.3–10 nm). The role of these PCN as support of manganese oxide for the gas-phase total catalytic oxidation of volatile organic compounds (VOCs) was evaluated. PCN with 5 % of Mn resulted in a higher nanoparticle dispersion (10 nm) compared to the sodic montmorillonite (17 nm). The highest catalytic activity was reached with PCN containing 10 % of Mn achieving a benzene, toluene and ortho-xylene oxidation of 54 %, 39 % and 34 %, respectively, at 350 °C. The catalyst was stable up to 36 h under these conditions.

Zeolite‐Based Materials for Catalytic Oxidation of Volatile Organic Compounds

AbstractOwing to the structural stability, modifiable acidity, and abundant pores/channels, zeolite‐based materials can act as catalysts or supports for effective conversion of volatile organic compounds (VOCs). In this review, a series of VOC oxidation processes catalyzed by zeolite‐based materials will be introduced, which include thermal oxidation, photocatalytic degradation, plasma‐driven removal, catalytic ozonation, microwave‐assisted degradation, and hybrid systems, where the specific roles, modification strategies, and structure–performance relationships of zeolites are discussed in depth. The following topics will also be covered, including the catalytic mechanisms of VOC oxidation, types of zeolite‐based materials in VOC catalytic oxidation, operation parameters in the processes, and reactor designs for efficiency optimization and cost control.

Templated synthesis of holy MIL-125(Ti) for the boosted photocatalytic performance in volatile organic compound oxidation and water treatment

Templated synthesis of holy MIL-125(Ti) for the boosted photocatalytic performance in volatile organic compound oxidation and water treatment

Diverse Effects of SO2-Induced Pt-O-SO3 on the Catalytic Oxidation of C3H6 and C3H8.

The effects of sulfur dioxide (SO2) in the catalytic purification of short-chain hydrocarbons are still controversial, and the exact role of SO2 on adsorption and reaction pathways during the catalytic oxidation of different volatile organic compounds (VOCs) remains unclear. Herein, a three-dimensional ordered macroporous Ce0.8Zr0.2O2 supported Pt nanoparticle monolithic catalyst (Pt/OM CZO) was synthesized to investigate these effects. Our findings uncover the diverse effects of SO2: Upon SO2 treatment, the coupling between the S 3p and Pt 5d orbitals promotes the Pt-O-SO3 structure in situ formed on the catalyst surface. The propene (C3H6) molecule readily binds with the oxygen atom in Pt-O-SO3, resulting in the accumulation of acetone and carbon deposition, thereby hindering C3H6 oxidation. Conversely, a cleaved oxygen atom within the Pt-O-SO3 structure enhances propane (C3H8) adsorption and activates the C-H bond, facilitating C3H8 oxidation. These insights are pivotal for advancing the frontier of sulfur-tolerant catalysts, addressing both economic and environmental challenges.

Enhanced photocatalytic oxidation of gaseous acetaldehyde using Fe-grafted ZnO nanocomposites in a continuous flow reactor

The purification of indoor air is a crucial application of photocatalysis, emphasizing the urgent need for more efficient photocatalytic systems. While photocatalytic oxidation of volatile organic compounds (VOCs) has been extensively studied in the liquid phase, effective removal of VOCs in the gaseous state in indoor air remains a significant challenge. This study focuses on the continuous gas-phase oxidation of gaseous acetaldehyde using ZnO and different weight percentage of Fe-grafted ZnO catalysts under light irradiation. The surface analysis using XPS and HR-TEM confirmed the presence of Fe(III) species, and UV–Vis-DRS analysis demonstrated a shift in the absorption edge towards the visible region. Real-time gas FTIR monitoring of acetaldehyde oxidation revealed that the 0.7% Fe(III)-grafted ZnO composite catalyst achieved a higher removal efficiency (74%) compared to bare ZnO and other Fe(III)-grafted ZnO ratios. The enhanced photocatalytic efficiency of acetaldehyde by Fe(III)-grafted ZnO supports indicated direct interfacial charge transfer (IFCT) from ZnO to Fe(III) species. Additionally, the Fe(III) cluster effectively improved the separation of electrons and holes, preventing their recombination and accelerating O₂ activation to generate O₂•⁻ radicals, which lead to high photocatalytic performance. The 0.7% Fe(III)-grafted ZnO also maintained its performance over a prolonged period of 360 min, showing excellent structural stability and durability across multiple cycles. This study highlights the possible synergistic effect of the ZnO and Fe systems, offering a new perspective on the photocatalytic decomposition of gaseous acetaldehyde in indoor environments.

Methods for Measuring Organic Carbon Content in Carbonate Soils (Review)

In world practice, the measurement of the mass fraction of carbon of organic compounds (Corg) in soils containing carbonates is carried out in various ways. An analysis of methods that allow solving this problem was carried out, including the latest approaches: thermogravimetry, differential scanning calorimetry, spectroscopy. It has been shown that the presence of CaCO3 does not prevent the use of the dichromatometric method (Tyurin, Walkley-Black) for determining Corg. The disadvantages of the method boil down to the laboriousness of the analysis, the need for constant presence of the operator, incomplete oxidation of organic compounds and environmental pollution. The method of measuring soil mass loss-on-ignition (LOI) is economical and rapid, but it gives an overestimated Corg content, which is associated with the inadequacy of the conversion factor of 1.724, the presence of adsorbed and chemically bound water, as well as mineral components decomposing at T = 105–550°С. The most relevant solution for finding Corg in carbonate soils is to use an analyzer and a calcimeter, although the accuracy of Corg measurements in the presence of carbonates is significantly reduced due to the quadratic summation of the errors of the two methods. The high cost of the device, maintenance, verification and repair limit its widespread use in soil laboratories. To measure the content of soil carbonates, it is possible to use both gravimetric (LOI) and volumetric (calcimeter) methods. The use of the latter is preferable for soils with a predominance of CaCO3 in carbonate composition. Preliminary removal of carbonates from soil samples is labor-intensive and can lead to partial loss of Corg due to acid extraction. The high cost of instruments and the lack of libraries of soil spectra hinder the development of vis-NIR and MIR spectroscopy as an alternative to “wet” chemistry methods. Continuing comparative studies will improve the understanding of the spatial patterns of distribution of carbon in soil organic compounds.

In Situ Photoelectrodeposited Polyaniline on Ti‐Doping Hematite For Highly Selective Photoelectrochemical Oxygen Demand Determination

AbstractChemical Oxygen Demand (COD), as a detection indicator of water pollution, is of particular importance in assessing organic pollution in water. Furthermore, accurate and simple measuring COD methods are essential for water quality assessment and pollution control. However, the photoelectrochemical oxygen demand (PECOD) measurement, as one of the measuring COD methods, is affected by the reaction of water splitting, which is one of the hindrances to the commercialization of the analytical method of the PeCOD measurement. Hence, to overcome this challenge, a new PANI/Ti:Fe2O3 photoanode is constructed by hydrothermal and photoelectrochemical (PEC) deposition methods and investigated their optical properties and photoactivity. Under optimization conditions, it is discovered that the oxidation of organic compounds produces a net steady‐state current (inet) is directly proportional to COD concentration, with a detection limit of 1 mM glucose solution and a wide linear detection range of 1–78.125 mM, which is suitable for high concentration of glucose detection. As has been noted, PANI/Ti:Fe2O3 photoanode overcomes the obstacles to the practical application and eventual commercialization of the PECOD technology.

Can we achieve atmospheric chemical environments in the laboratory? An integrated model-measurement approach to chamber SOA studies.

Secondary organic aerosol (SOA), atmospheric particulate matter formed from low-volatility products of volatile organic compound (VOC) oxidation, affects both air quality and climate. Current 3D models, however, cannot reproduce the observed variability in atmospheric organic aerosol. Because many SOA model descriptions are derived from environmental chamber experiments, our ability to represent atmospheric conditions in chambers directly affects our ability to assess the air quality and climate impacts of SOA. Here, we develop an approach that leverages global modeling and detailed mechanisms to design chamber experiments that mimic the atmospheric chemistry of organic peroxy radicals (RO2), a key intermediate in VOC oxidation. Drawing on decades of laboratory experiments, we develop a framework for quantitatively describing RO2 chemistry and show that no previous experimental approaches to studying SOA formation have accessed the relevant atmospheric RO2 fate distribution. We show proof-of-concept experiments that demonstrate how SOA experiments can access a range of atmospheric chemical environments and propose several directions for future studies.

Oxidation of Organic Compounds in Cooking Fumes by Combining Nonthermal Plasma with Mn/HZSM-5 Catalysts

Oxidation of Organic Compounds in Cooking Fumes by Combining Nonthermal Plasma with Mn/HZSM-5 Catalysts

Harnessing Solar Power for Oxidation of Organic Compounds by Re(I)Dipyrrinato Complexes.

Metal dipyrrinato complexes of 4d and 5d metals have distinctive features such as high absorption coefficients in the visible section and room temperature phosphorescence in the red region. This work demonstrates the light-assisted oxidation of organic compounds employing rhenium(I)dipyrrinato complexes as catalysts. The heavy atom effect in rhenium(I)dipyrrinato complexes leads to the formation of long-lived triplet excited states, and these complexes can generate singlet oxygen in excellent yields (up to 84 %). A method was developed for photocatalytic aerobic oxidation of sulfides and amines using only 0.05 mol % and 0.025 mol % of the rhenium(I)dipyrrinato complexes, respectively. The method is efficient, and within 2 h, a variety of substrates were oxidized to produce sulfoxides and imines in high yields (up to 97 %). Rhenium(I)dipyrrinato complexes work very well both in visible light and sunlight, making them promising candidates for photocatalytic applications.

Asymmetric oxygen vacancies of self-supporting Co3O4/CuOx on Cu foam boosts propane total oxidation

As a low-cost and environmentally friendly transition metal oxides material, the Co3O4 has good catalytic activity for volatile organic compounds (VOCs) oxidation. However, the active components of powder cobalt-based catalysts may present uneven distribution and aggregation, thus affecting the catalytic efficiency. Herein, the Co/Cu-CF monolithic catalyst with asymmetric oxygen vacancies was developed through in-situ growth of Cu(OH)2 nanoarrays on Cu foam, which exhibits excellent performance for propane oxidation (T90 at 215 ℃). It is impressive that the catalyst shows satisfactory stability in terms of long-term, cyclic and water resistance. The results indicate that the existence of nanoarrays can provide a rich load surface and better disperse the active components, which effectively facilitates the interface interaction between cobalt and copper, inducing the generation of asymmetric oxygen vacancies. And, the activity of catalyst was significantly improved owing to the double activation effect of asymmetric oxygen vacancy on molecular oxygen and lattice oxygen. Therefore, this research offers a novel approach for designing efficient nanoarray monolithic catalysts for VOCs oxidation and other environmental applications.

Selective recovery of manganese from spent ternary lithium-ion batteries for efficient catalytic oxidation of VOCs: Unveiling the mechanism of activity Enhancement in recycled catalysts

With the widespread application of ternary lithium-ion batteries (TLBs) in various fields, the disposal of spent TLBs has become a globally recognized issue. This study proposes a novel method for reutilizing metal resources from TLBs. Through selective oxidation, manganese in a leaching solution of TLBs was converted into MnO2 with α, γ, and δ crystal phases (referred to as T-MnO2) for catalytic oxidation of volatile organic compounds (VOCs), while efficiently separating manganese from high-value metals such as nickel, cobalt, and lithium, achieving a manganese recovery rate of 99.99%. Compared to similar MnO2 prepared from pure materials, T-MnO2 exhibited superior degradation performance for toluene and chlorobenzene, with T90 decreasing by around 30 °C. The acidic synthesis environment provided by the leaching solution and the doping of trace metals altered the physicochemical properties of T-MnO2, such as increased specific surface area, elevated surface manganese valence, and improved redox performance and oxygen vacancy properties, enhancing its catalytic oxidation capacity. Furthermore, the degradation pathway of toluene on T-γ-MnO2 was inferred using thermal desorption-gas chromatography/mass spectrometry (TD-GC/MS) and in-situ DRIFTs. This study provides a novel approach for recycling spent TLBs and treating VOCs catalytically.

Mn/CeO2 contains enriched surface lewis acid sites and pore structures accelerated catalytic oxidation of propane at low temperature

The development of highly efficient non-precious metal catalysts for the low-temperature catalytic oxidation of volatile organic compounds (VOCs) is a critical imperative in VOCs control. In this study, a series of highly active CeMnOx catalysts with Mn-doped CeO2 were investigated. The catalysts (WHSV=30,000 mL g−1 h−1) exhibited the highest catalytic propane oxidation activity (T90 = 230 °C) and excellent stability over 600 h, When the Mn:Ce ratio was 2.5. The introduction of Mn doping resulted in modifications to the pore structure of CeO2, leading to an increase in specific surface area and enhanced gas transfer kinetics. Additionally, it induced surface electronic defects and elevated the concentration of acidic sites, thereby facilitating the adsorption and activation of propane. Consequently, these improvements contributed to an enhanced catalytic performance of the catalyst. The in-situ DRIFTS infrared spectra revealed that Mn doping reduced the activation energy of the reaction and facilitated the conversion of acetone groups as well as decomposition of carboxylic acid groups.

Functionalization of Filter Media for Improved Crystalline Silica Analysis Using Raman Spectroscopy

ABSTRACTRespirable crystalline silica (RCS) poses significant health risks in workplaces, including underground coal mines, metal and nonmetal mining, construction sites, fire suppression, and oil and gas industries. Raman spectroscopy offers a promising avenue for direct analysis of RCS on sample filters with minimal pretreatment. However, the presence of organic compounds (OC) in the samples can generate fluorescence signals that interfere with RCS measurements, potentially saturating the detector even at short integration times, particularly when using portable Raman instruments. This study explores a novel approach to address these challenges by functionalizing filters with a hydroxyapatite/silver bromide/titanium dioxide (HAT) photocatalyst, facilitating the oxidation and removal of OC using the Raman excitation laser. Photocatalytic degradation experiments conducted on polyvinyl chloride (PVC) filters preloaded with HAT and anatase titanium dioxide (TiO2) particles demonstrated that HAT significantly enhances the degradation of OC, such as oxalic acid, under visible light irradiation compared to TiO2. Additionally, fluorescence interferences were reduced for coal dust samples analyzed on functionalized silver filters using a portable Raman instrument. The efficacy of HAT in OC photocatalytic degradation on silver filters was further confirmed using a benchtop micro‐Raman system. Filter functionalization had minimal impact on filtration efficiencies and pressure drops, indicating the feasibility of this approach for improving RCS analysis while maintaining filter performance.