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In this paper, ammonium perchlorate (AP) as a strong oxidant has been added into Al/polyvinylidene difluoride (PVDF) nanothermites. Based on homogeneous structure of PVDF, shorter reaction contact between components can be obtained for more outstanding ignition and combustion performance. Water contact angle experiments were conducted to evaluate the hydrophobicity of the composite films, indicating that the suitability of composite material has enhanced under wet environment. According to TG-DSC results, the thermal decomposition of AP can improve the whole heat release process, which theoretically has excellent combustion performance advantages. Constant volume pressure tests were conducted to assess the energy release properties of the films compared with Al@PVDF films. Combustion performance in air was evaluated by employing optical sensors and a high-speed camera to measure factors such as the ignition delay time, light intensity and combustion flame propagation. After adding 15 % AP, the maximum pressure of Al/AP@PVDF film is 0.0960 Mpa, and that of Al@PVDF film is 0.0805 Mpa. The maximum pressure of the film is increased by nearly 19.25 %. Compared with Al@PVDF film, the ignition delay time of Al/AP@PVDF film is shortened by 45 ms, and the light intensity is increased by nearly 93.39 %. However, excessive AP content adversely impacted film formation efficiency, leading to the deterioration of various properties. Therefore, an optimal AP content of approximately 15 % in Al/AP@PVDF system was finally identified. [ABSTRACT FROM AUTHOR]

Two mononuclear complexes, [Cu(L1)2] (complex 1) and [Cu(HL2)2](NO3)2 (complex 2) where HL1 is 1-((cyclohexylmethylimino)methyl)-naphthalen-2-ol and HL2 is 4-bromo-2-((2-morpholinoethylimino)methyl)phenol, have been synthesized under mild conditions and characterized by different standard analytical methods. Single crystal X-ray diffraction analysis shows that the copper atoms in both copper(II) complexes are in a square planar geometry. These complexes have been used as catalysts in the oxidation of benzyl alcohol and benzyl alcohol with various substituents in the presence of NaOCl as the terminal oxidant. The results show that complex 1 acts as a better catalyst than the other with the highest yield of 91% in the case of 4-methoxy benzyl alcohol oxidation. The copper complex transfers the oxygen of sodium hypochlorite to the alcohol to produce the aldehyde. The use of NaOCl as an oxidant in alcohol oxidation is rare although it is cheap and nonexplosive. [ABSTRACT FROM AUTHOR]

Synthetically challenging spirolactams were developed in good yields and regio-selectivity through a step-up oxidative dearomatization of easily accessible arenols tethered to esters in the presence of quaternary ammonium tribromide as an economic oxidant and amines. The reaction mechanism associated with this unprecedented dearomative lactamisation has been forecasted with a series of controlled experiments and DFT studies. [ABSTRACT FROM AUTHOR]

Background: Recent evidence suggests neuro‐immune mechanisms may link dietary patterns to chronic painful conditions (CPC). In the research field of oro‐facial pain (OFP), studies focuses primarily on dietary mechanical limitations due to pain and dysfunction. Objective: This narrative review aimed to overview the role of nutrition on CPC, with emphasis on temporomandibular disorder (TMD), enlightening OFP researcher on dietary assessment possibilities and providing directions for studies in the field of OFP and nutrition. Methods: A PubMed database search was performed using the MeSH and non‐MeSH descriptors: "temporomandibular joint disorder"; "orofacial pain"; "musculoskeletal pain"; "chronic pain disorders"; "nutrition"; "diet"; "dietary therapy"; "dietary intake" and "inflammation". No time restrictions were applied. Literature reviews, systematic reviews, meta‐analyses and clinical and pre‐clinical trials were included. Results: Exogenous oxidants from unhealthy dietary patterns may contribute to peripheral and central pro‐inflammatory immune signalling leading to peripheral and central sensitization. Furthermore, diets rich in bioactive compounds are suggested to contribute to pain management of CPC. High dietary intake of ultra‐processed foods impacts the quality of the diet and shows adverse health outcomes. In this context, the role of nutrition on TMD remains overlooked. Conclusion: Considering diet may influence CPC, allied with the scarcity of studies evaluating the role of nutrition on TMD, well‐designed clinical trials based on dietary assessments and measurements capable of evaluating food quality, UPF consumption and nutrient adequacy—added to serum nutrient levels evaluation—are suggested. [ABSTRACT FROM AUTHOR]

Ruthenium (Ru) is an important platinum group metal for the manufacture of advanced materials owing to its chemical and physical properties. Generally, it is extremely difficult to dissolve Ru metal by using acidic solutions containing strong oxidizing agents. Therefore, pretreatments like alkali fusion roasting at high temperature are practiced to render the Ru metal soluble in aqueous solution. In this work, a simple procedure was proposed to dissolve Ru metal at room temperature without any pretreatments. The dissolution procedure consisted of two steps: (i) oxidation of Ru metal to RuO4– by using pure NaClO solution; (ii) reduction of RuO4– to stable Ru2OCl104– by using HCl as a reducing agent. The role of NaClO and HCl in the dissolution of Ru metal was discussed on the basis of the potential-pH diagram and the corresponding oxidation and reduction reactions. The effect of several parameters like the concentration of NaClO and HCl, temperature, time, and pulp density was investigated. Optimum conditions were obtained to completely dissolve Ru metal by using NaClO and HCl solution without alkali fusion. [ABSTRACT FROM AUTHOR]

The oxidation property of liquid-phase sintered silicon carbide (LPS-SiC) ceramics with ZrB 2 addition was studied after oxidation test in air at 1400 °C. The results indicate that the addition of ZrB 2 decreased the degree of polymerization (DOP) of the silicate networks in the oxide layer, suppressing the additional oxidation caused by residual bubbles in the oxide layer of LPS-SiC, which bypassed the layer and directly corroded the material internally. After 100 h of oxidation, the additional oxidation depth was found to be 125 μm in the sample without ZrB 2 and 0 μm in those containing 10 wt% ZrB 2. Simultaneously, the decrease in DOP facilitates the migration of crystalline phases. The generated ZrSiO 4 can migrate and aggregate at the interface between the surface oxide layer and the SiC/ZrB 2 matrix, forming a continuous ZrSiO 4 barrier. This impedes the diffusion of the oxidant and enhances the oxidation resistance. However, an insufficient ZrB 2 content leads to a discontinuous ZrSiO 4 layer, thereby weakening its protective effect. Simultaneously, a decrease in DOP increases the rate of oxygen diffusion, resulting in an increase in the oxidation layer thickness. This study contributes to a better understanding of the failure mechanisms of LPS-SiC in oxidizing environments and provide a reference for the design of oxidation-resistant LPS-SiC materials. [ABSTRACT FROM AUTHOR]

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Due to the high oxidation potential of arenes and alkenes, previous methods of benzylic and allylic C–H oxidation necessitated the use of strong oxidizing agents, metal catalysts, or free radical initiators (such as photocatalysts or hydrogen atom transfer reagents) to be effective. Herein, we employ oxygen to generate a triple-spin charge transfer state with π-conjugated compounds effectively accessing the triplet excited states of arenes, followed by energy transfer to form singlet oxygen facilitating C–H bond oxidation. Distinct from previous oxidations, it is the first time that a series of natural products and drug molecules (27 examples) are selectively oxidized without any catalysts or additives. The transformation can be implemented under sunlight to produce valuable unsaturated (aromatic) ketones and only water as waste, which meets every one of the 12 principles of green chemistry. [ABSTRACT FROM AUTHOR]

The first study on oxidative sulfonamidation of camphene is presented. By varying the reaction conditions, the nature of the sulfonamide, the oxidizing agent, the ratio of the reagents, and the solvent, it is possible to control not only the direction of amidation of the double bond of camphene, leading to the formation of the corresponding amides or amidines, but also the rearrangement or retention of the camphene structure. In the NIS-induced reaction, no rearrangement occurs, leading to N-sulfonylamidine derivatives of isocamphane. The NBS-induced reaction takes place with solvent (acetonitrile) intersection and with or without rearrangement, resulting in N-sulfonylamine with isocamphane or camphane motif, depending, strikingly, on the ratio of the reactants. A mechanism that explains the diversity of products has been proposed and confirmed by theoretical calculations. It includes various intermediates formed via electrophilic addition of a halogen, such as an open carbocation for Br+, or the anchimerically assisted iodonium cation for I+. Additionally, the basicity of the reaction medium can change depending on the ratio of the reagents. For example, in CH2Cl2, which is incapable of being trapped by the intermediate cations, the formation of bromosulfonamide occurs only with triflamide due to the highest halogening activity of the intermediate CF3SO2NHBr. The structure of the products formed in up to 96% yield was proved by NMR, HRMS and, for the key products, by X-ray analysis. When performing the NBS-induced bromosulfonation of camphene using triflamide with subsequent addition of potassium carbonate (K2CO3), no dehydrobromination occurred. However, when using cesium fluoride (CsF) as a base, an unexpected quinazoline product was obtained. This opens up the possibility for further transformations. [ABSTRACT FROM AUTHOR]

A variety of 2-substituted 3-selanyl-chromenones are readily prepared through a cascade selanylation/cyclization of alkynyl aryl ketones with sulfonoselenoates. This transformation is performed under metal-free conditions and does not require an additional oxidant. It also has the advantage of broad functional group tolerance and scalability. [ABSTRACT FROM AUTHOR]

tert‐Butyl hydroperoxide (tBuOOH, TBHP) is a commonly used hydroperoxide in many oxidation processes. The primary factors contributing to the increasing usefulness of TBHP include its affordability, eco‐friendliness, exceptional efficacy, and capacity to substitute harmful or rare heavy metal oxidants. In this sexennial update, we thoroughly and critically examined the most noteworthy applications of TBHP in C−H functionalization and heteroatom‐heteroatom bond formation reactions from 2018 till the present. The review has been subdivided based on the nature of the bonds being formed. The review focuses on the advantages and disadvantages of using synthetic organic transformations, as well as the breadth of their use and the underlying mechanisms involved. [ABSTRACT FROM AUTHOR]

α‐costic acid, the main component of Dittrichia viscosa collected from Morocco, was converted to its derivative γ‐costic acid, both products were the subject of a transformation to obtain new oxygenated derivatives (vicinal diols). The starting material, α‐costic acid was converted to methyl‐α and γ‐costate. The two esters were transformed to vicinal diols employing two reagents I2/t‐BuOOH and diluated KMnO4. The first one was the regioselectivity activation of carbon‐carbon double bond using iodine, creating an iodonium intermediate which react with t‐BuOOH to give corresponding diol and the second one was the exploitation of KMnO4 as an effective and environmentally friendly oxidant. These simple and effective oxidants led us to two natural vicinal diols α and γ esters costic with a good yield. [ABSTRACT FROM AUTHOR]

A homogeneous catalyst system consisting of Mn(OAc)2 and 2‐picolinic acid was studied for alcohol oxidation using peracetic acid as the oxidant. Catalyst loadings as low as 0.01 mol% could be utilized and the system compared well to other peroxide based methods. The utilization of continuous flow allowed the fast, exothermic reactions to be carried out in a safe and scalable manner. [ABSTRACT FROM AUTHOR]

A visible‐light‐promoted strategy for the decarboxylative C‐3 carbamoylation of quinoxalinone scaffolds is developed. This approach initiates through the formation of an EDA complex between oxamic acid and quinoxalinone. Successive SET and decarboxylative carbamoylation construct the C−C bond. This method utilizes aerial oxygen as the green oxidant and eradicates the process from the use of external photocatalysts and transition metals. Detailed synthetic and photophysical studies enlighten the reaction pathway. [ABSTRACT FROM AUTHOR]

Herein, we report a general copper‐catalyzed method for the tunable oxygenative rearrangement of tetrahydrocarbazoles to cyclopentyl‐bearing spiroindolin‐2‐ones and spiroindolin‐3‐ones. The method demonstrates excellent chemoselectivity, regioselectivity, and product control simply by using the H2O and O2 as oxygen source, respectively. This open‐flask method is safe and simple to operate, and no other chemical oxidants are required. Besides, inspired from the unique pathway of 1, 2‐migration rearrangement, a highly controllable hydroxylation of indoles for the construction of C3a‐hydroxyl iminium indolines was also developed. Mechanistic experiments suggest that a single‐electron transfer‐induced oxidation process is responsible for the tunable selectivity control. [ABSTRACT FROM AUTHOR]

Aging is characterized by a progressive decline in physiological function and underlies several disabilities, including the increased sensitivity of cells and tissues to undergo pathological oxidative stress. In recent years, efforts have been made to better understand the relationship between age and oxidative stress and further develop therapeutic strategies to minimize the impact of both events on age‐related diseases. In this work, we review the impact of the oxidant and antioxidant systems during aging and disease development and discuss the crosstalk of oxidative stress and other aging processes, with a focus on studies conducted in elderly populations. [ABSTRACT FROM AUTHOR]

In the photo-oxidation processes, the oxidants play a vital role in removing color. However, a comprehensive comparison of the three common oxidants' performance for color removal from textile wastewater has not been conducted. Also, the effect of periodate in the presence of ferrous for color removal has not been investigated extensively. The object of this study was to evaluate and compare the effect of three common oxidants on the removal of color. Central composite design was employed to design the experiments and evaluate the interaction between parameters and their impact on color removal. The photo-oxidation processes were carried out under UV light irradiation (60 W) in the presence of ferrous (Fe2+) and three oxidants, namely hydrogen peroxide (H2O2), sodium persulfate (SPS), and sodium periodate (SPI). The four main variables were the reaction time, the pH value, the concentration of oxidants, and the concentration of ferrous. Finally, the optimal values for all parameters were shown and these three processes were compared with each other. Although the UV/SPI/Fe2+ process had the highest color removal (96%), by considering all parameters, the UV/SPS/Fe2+ was a better choice because of its high efficiency, low reaction time, and low oxidant concentration. The results suggested that the photo-Fenton process could not be a good option among these processes, as it required the longest reaction time and highest oxidant concentration while achieving the lowest removal efficiency (82%). The results of this study can help with the decision-making process to select a better process for textile wastewater treatment. [ABSTRACT FROM AUTHOR]

Microwave-based reactions have gained traction in recent years due to their ability to enhance reaction rates and yield while reducing energy consumption. Also, according to the conception of 'waste to materials', various waste feeds are intensively sought to be tested. The experimental setup of this study involved varying pH levels, oxidation agents, and precipitation agents to optimize the synthesis process of iron red based on waste iron sulfate. The selection of oxidation and precipitation agents was found to significantly influence the pigment synthesis process. Various oxidizing agents, including hydrogen peroxide and atmospheric air, were evaluated for their effectiveness in promoting the oxidation of ferrous ions to ferric ions, essential for pigment formation. Additionally, different precipitation agents such as sodium hydroxide and ammonia solution were assessed for their ability to precipitate iron hydroxides and facilitate pigment particle formation. The characterization of synthesized pigments revealed promising results in terms of quality and color properties. Helium Ion Microscopy (HIM) analysis confirmed the formation of well-defined pigment particles with controlled morphology. X-ray diffraction (XRD) studies provided insights into the crystalline structure of the pigments, indicating the presence of characteristic iron oxide phases. By improving this technology, waste iron sulfate can be efficiently transformed into valuable iron pigments, offering a sustainable solution for waste management while meeting the growing demand for high-quality pigments. [ABSTRACT FROM AUTHOR]

Oxidation behavior of additively manufactured ZrB2–SiC in air and in CO2 is reported in the temperature range of 700–1000 °C. Observed scale morphologies in air and in CO2 were similar, featuring an outer borosilicate layer and an inner porous zirconia layer containing partially oxidized silicon carbide particles and remnant borosilicate products. Oxide scale thicknesses and parabolic scaling constants in air were approximately twice those observed in CO2 across all studied temperatures. Activation energies for oxidation of 140 ± 20 kJ/mol in air and 110 ± 20 kJ/mol in CO2 were determined, indicating similar diffusion processes that appear to be rate-limiting. The formation of protective scales across wide temperature ranges both in air and in CO2 makes additively manufactured ZrB2–SiC an attractive candidate for high-temperature industrial process applications featuring varied oxidants such as heat exchangers. [ABSTRACT FROM AUTHOR]

Oxidative α-C(sp3)–H alkylation of N -arylated glycine derivatives with 4-alkyldihydropyridine derivatives (alkyl-DHPs) as versatile alkyl radical precursors has been developed. Utilizing visible-light-driven photoredox catalysis and ammonium persulfate as an oxidizing agent, this methodology facilitates the site-selective alkylation of glycine derivatives, enabling the site-selective alkylation of peptides. The reaction exhibits broad substrate scope, including various alkyl radicals and acid-labile functional groups. This approach expands the synthetic toolbox in peptide chemistry, offering a mild and efficient method for the synthesis of modified peptides. [ABSTRACT FROM AUTHOR]

Sr 0.99 La 0.01 TiO 3 (SLT10) colossal permittivity (CP) ceramic materials were synthesized using solid phase method and secondary heat treated using mixed oxidant 35%Bi 2 O 3 –10%Al 2 O 3 –20%MgO–25%CuO–10%SiO 2 oxidant. The heat treatment atmospheres were chosen as O 2 , air, and Ar to correspond to different oxygen partial pressures. The dielectric properties of the Sr 0.99 La 0.01 TiO 3 -Percolated (SLT10-P) ceramics were investigated, and the contribution of the oxidant to the resistivity enhancement was verified by complex impedance spectroscopy and DC resistivity tests. Excellent dielectric properties were obtained for SLT10-P Air ceramic sample (16543 for dielectric permittivity and 0.016 for loss tangent), and the resistivity was increased from 2.13 × 108 Ω cm (SLT10) to 1.23 × 1011 Ω cm (SLT10-P Air). The resistance degradation mechanism of SLT10-P ceramics and oxygen vacancy migration in the process of resistance degradation were studied by using resistance monitoring device and thermally stimulated depolarization currents (TSDC) test. The introduction of oxidant optimizes the temperature stability and resistivity of SLT10 ceramics, but it will lead to the decrease of dielectric permittivity. The atmosphere of heat treatment changed the concentration of oxygen vacancy in ceramics. When SLT10-P O 2 was treated in O 2 atmosphere, the concentration of oxygen vacancy in ceramics decreased, which led to the decrease of dielectric permittivity and the increase of grain boundary resistance. For SLT10-P Ar ceramic, more oxygen vacancies and free electrons are induced by low oxygen partial pressure heat treatment, which enhances the dipole effect of electron pinning defects and leads to colossal dielectric permittivity, but high concentration of oxygen vacancies will affect the resistance decline. In SLT10-P Air ceramic, the coexistence of colossal permittivity and low loss tangent and high resistance is realized. [ABSTRACT FROM AUTHOR]

The multi-stage leaching of chromite in HCl-Na2CrO4, system has been studied, and the leaching kinetics of main metal elements in chromite has been discussed. The results show that under the optimal conditions of particle size of 45~75 µm, oxidizing agent Na2CrO4, dosage of 0.6 times of theoretical dosage, reaction time of 5 h, reaction temperature of 453.15 K, ball to material mass ratio of 1/1, stirring speed of 30 r/min, liquid volume to solid mass ratio of 4 mL/1 g, the three-stage cyclic leaching is carried out, the leaching rates of Cr, Fe, Al and Mg can reach 91.98%, 94.54%, 76.62% and 78.03 %, respectively. The acid leaching reaction of chromite is controlled by interfacial chemical reaction. The apparent activation energies of Cr, Fe, Al and Mg are 45.80, 40.43, 42.08 and 43.54 kJ/mol, respectively. In the range of 373.15~473.15 K, and the leaching effect is good. [ABSTRACT FROM AUTHOR]

Air pollution is one of the most critical environmental challenges and threats to humans. Ozone and nitrogen dioxide (their sum is defined as oxidant, OX) are among the criteria air pollutants and have serious health effects. Oxidant is affected by emission sources in local and regional domains. In this work, a systematic and critical review is conducted on the existing studies of the local and regional oxidant contributions. The systematic review focuses on the publication year, journal rank, study location, and keyphrase analysis. The critical review examines the analyzed parameters, and temporal variations and the data analysis of local and regional contributions of oxidant. The systematic review showed that the studies were conducted in 13 different countries and were published in 19 scientific journals. The critical review indicated that O3, NO, NO2, NOx, and OX were used in all the studies. Furthermore, meteorological parameters of temperature and wind speed were mostly employed in the literature. Due to the substantial effects of emission and meteorological parameters on OX, different time scales were defined so that these effects could be evaluated separately. Our findings revealed that the highest OX's local and regional contributions belong to daily (24-h average) and daylight time scales, respectively. The statistical analysis of the present study shows that the regional contribution values have less variations than the local contribution ones. This is due to the fact that the regional contribution values are influenced by a larger spatial domain and are less dependent on emission sources of each location. [ABSTRACT FROM AUTHOR]

Musculoskeletal disorders encompass a wide range of conditions that impact the bones, joints, muscles, and connective tissues within the body. Despite the ongoing debate on toxicity and administration, ozone demonstrated promise in managing several musculoskeletal disorders, modulating pain and inflammation. A literature search was conducted. The research design, methods, findings, and conclusions of the studies were then examined to evaluate the physiological effects, clinical application, controversies, and safety of the application of ozone in musculoskeletal medicine. Ozone application demonstrates considerable therapeutic applications in the management of musculoskeletal disorders, including fractures, osteoarthritis, and chronic pain syndromes. Despite these advantages, studies have raised concerns regarding its potential toxicity and emphasized the importance of adhering to stringent administration protocols to ensure safety. Additionally, heterogeneities in patient reactions and hazards from oxidizing agents were observed. Given its anti-inflammatory and analgesic qualities, ozone therapy holds potential in the management of several musculoskeletal disorders. Additional high-quality research with long follow-up is required to refine indications, efficacy and safety profile. Finally, for wider clinical acceptability and utilization, the development of international recommendations is essential. [ABSTRACT FROM AUTHOR]

Oxidative cyclization of 4-penten-1-ols using a Pd catalyst and n-BuONO or n-BuONO/p-benzoquinone afforded 3-hydroxy- and 3-methoxytetrahydropyrans via terminal selective nucleophilic attack. The radicals formed from n-BuONO and O2 operate as critical oxidants and ligands for Pd. [ABSTRACT FROM AUTHOR]

Cp2Fe-mediated electrochemical synthesis of a diverse array of phosphorylated azaspiro[4.5]di/trienones has been developed, which demonstrated broad substrate scope and good diastereoselectivity. It represents the first example of electrochemical synthesis of phosphorylated azaspiro[4.5]di/trienones, circumventing the need for external oxidants and high temperatures. Moreover, a plausible mechanism including radical-initiated dearomative cyclization driven by ferrocenium cations has been provided, which was supported by the related mechanistic study. [ABSTRACT FROM AUTHOR]

The direct anodic conversion of alkali carbonates in aqueous media provides access to peroxodicarbonate, which is a safe to use and green oxidizer. Although first reports date back around 150 years, its low concentrations and limited thermal stability have consigned this reagent to oblivion. Boron-doped diamond anodes, novel electrolyser concepts for heat dissipation, and the mixed cation trick allow record breaking peroxodicarbonate concentrations >900 mM. The electrochemical generation of peroxodicarbonate was already demonstrated on a pilot scale. The inherent safety is ensured by the limited stability of the peroxodicarbonate solution, which decomposes under ambient conditions to oxygen and facilitates subsequent downstream processing. This peroxide has, in particular at higher concentrations, an unusual reactivity and seems to be an ideal reagent when peroxo-equivalents in combination with alkaline base are required. The conversions with peroxodicarbonate include the Dakin reaction, epoxidation, oxidation of amines (aliphatic and aromatic) and sulfur compounds, deborolative hydroxylation reactions, and many more. Since the base equivalents also represent the makeup chemical for pulping plants, peroxodicarbonate is an ideal reagent for the selective degradation of lignin to vanillin. Moreover, peroxodicarbonate can be used as a halogen-free bleaching agent. The emerging electrogeneration and use of this green platform oxidizer are surveyed for the first time. [ABSTRACT FROM AUTHOR]

A comprehensive process model for 4H‐SiC oxidation is created and calibrated against a very large collection of experimental data. The model reproduces measured oxide thickness for Si‐face, C‐face, and a‐face SiC wafers, in the temperature range 950–1500 °C, in the pressure range 0.25–4.0 atm, in the thickness range 3–1600 nm, and for SiC doping ranging between 1019 cm−3 n‐type and 1019 cm−3 p‐type. The model is based on the Massoud model: Oxidation is driven by oxidants (O2, H2O) which are present in the gas phase, diffuse through the oxide, and form SiO2 at the oxide–SiC interface. For thin oxides, the interface reaction rate includes empirical correction terms which add to the oxidation rate, and which asymptotically approach zero with increasing oxide thickness. For dry oxidation, a remarkable dependence on the O2 partial pressure is discovered: For thick oxides, the oxidation rate scales linearly with the pressure, but the correction term for thin oxides scales with the square root of the pressure. This suggests that the atomistic processes responsible for the fast initial growth of oxides involve the splitting of O2 molecules into two O atoms. [ABSTRACT FROM AUTHOR]

The cycloneophylpalladium(II) complexes [Pd(CH2CMe2C6H4)(κ2-N,N′-L)], 1 or 2, with L = RO(CH2)3N(CH2-2-C5H4N)2, with R = H or Me, respectively, react with either dioxygen or hydrogen peroxide in the presence of NH4[PF6] to give rare examples of the corresponding hydroxopalladium(IV) complexes [Pd(OH)(CH2CMe2C6H4)(κ3-N,N′,N′′-L)][PF6], 3 or 4. The complexes 3 and 4 are stable at room temperature and have been structurally characterized. On heating a solution of 3 or 4 in moist dimethylsulphoxide, selective reductive elimination with C(sp2)–O bond formation is observed, followed by hydrolysis, to give the corresponding pincer complex [Pd(OH)(κ3-N,N′,N′′-L)][PF6] and 2-t-butylphenol as major products. A more complex reaction occurs in chloroform solution. The mechanisms of reaction are discussed, supported by DFT calculations. [ABSTRACT FROM AUTHOR]

Copper, iron–chloride ionic liquids (ILs) were immobilized on SBA-15 via N-methylimidazole grafting with C–Cl in chloropropylsilane pre-anchored on SBA-15, followed by FeCl3 and CuCl2 coordination to imidazolium chloride to generate a double metal IL-supported mesoporous composite (SIL-CuFe). The prepared composite exhibited an effective catalytic performance for the solvent-free oxidation of styrene to benzaldehdye (BzH) with H2O2 oxidant, offering 51% conversion, a turnover number (TON) of 330.5 mol molFe+Cu−1, and a selectivity of 71% at a reaction temperature of 70 °C. The composite catalyst can be easily recovered and effectively reused without a significant loss in activity and selectivity. The quenching experiments by adding tert-butanol (TBA), 1,4-benzoquinone (p-BQ) and L -histidine (L -HIS) in the reaction system were conducted to identify the type of reactive O species, specifically ˙OH, ˙O2−, and 1O2, produced by catalyst activation with H2O2 and played a main role in the oxidation. The reaction mechanism of the oxidation process is also proposed. [ABSTRACT FROM AUTHOR]

Copper, iron–chloride ionic liquids (ILs) were immobilized on SBA-15 via N-methylimidazole grafting with C–Cl in chloropropylsilane pre-anchored on SBA-15, followed by FeCl3 and CuCl2 coordination to imidazolium chloride to generate a double metal IL-supported mesoporous composite (SIL-CuFe). The prepared composite exhibited an effective catalytic performance for the solvent-free oxidation of styrene to benzaldehdye (BzH) with H2O2 oxidant, offering 51% conversion, a turnover number (TON) of 330.5 mol molFe+Cu−1, and a selectivity of 71% at a reaction temperature of 70 °C. The composite catalyst can be easily recovered and effectively reused without a significant loss in activity and selectivity. The quenching experiments by adding tert-butanol (TBA), 1,4-benzoquinone (p-BQ) and L -histidine (L -HIS) in the reaction system were conducted to identify the type of reactive O species, specifically ˙OH, ˙O2−, and 1O2, produced by catalyst activation with H2O2 and played a main role in the oxidation. The reaction mechanism of the oxidation process is also proposed. [ABSTRACT FROM AUTHOR]

The demand for nickel, cobalt, and manganese is increasing owing to their critical role in the performance of lithium-ion batteries. Precipitation is simpler to operate than solvent extraction in the separation of metal ions. In this work, precipitation-based procedures were developed to separate Co(II), Mn(II) and Ni(II) from synthetic chloride solutions. Dimethylglyoxime (DMG) was effective in selectively precipitating Ni(II) from the chloride solutions containing Co(II) and Mn(II). Solution pH greatly affected the precipitation of Ni(II) by DMG. In the first procedure, Ni(II) was first precipitated using DMG from solution with initial pH 6 at a DMG/Ni(II) molar ratio of 3, a reaction time of 30 min and then Co(II) was separated from the filtrate by precipitation with Na2S, with optimal conditions being an initial pH of 6, a Na2S/Co(II) molar ratio of 2 and a reaction time of 15 min. In the second procedure, both Ni(II) and Co(II) was simultaneously precipitated with Na2S, leaving Mn(II) in the filtrate. Then the mixed sulfides of Co(II) and Ni(II) were dissolved by using HCl solution containing NaClO as an oxidizing agent. From the leaching solution, Ni(II) was separated by precipitation with DMG. Optimum conditions for the separation conditions were obtained. In both procedures, the separation degree among the three metal ions was higher than 99%. The developed procedures were simple and effective for the separation of the three metal ions compared to solvent extraction. [ABSTRACT FROM AUTHOR]

A tandem Cu‐catalyzed oxidation‐intramolecular Cannizzaro reaction leading to bioactive α‐hydroxyesters from α‐hydroxyketones is reported. The process uses oxygen as a sole oxidant to achieve the formation of glyoxals, which are efficiently converted in situ to important α‐hydroxyesters. The mechanistic insights are provided by isotopic labeling and supported by DFT calculations. The transformation proved a robust synthetic tool to achieve the synthesis of human metabolites and hydroxyl esters of various biologically active steroid derivatives. [ABSTRACT FROM AUTHOR]

A novel alkaline serine protease, derived from the Staphylococcus aureus strain ALA1 previously isolated from dromedary milk, was subjected to purification and characterization. Optimal protease production occurred under specific culture conditions. The purified protease, designated S. aureus Pr with a molecular mass of 23,662 Da and an N-terminal sequence, showed an approximately 89% similar identity with those of other Staphylococcus strains. It exhibited its highest enzymatic activity at a pH of 10.0 and 60 °C in the presence of 3 mM Ca2+. Remarkable thermostability was observed at temperatures up to 70 °C and within a pH range of 6.0 to 10.0 for 2 h. The presence of Ca2+ or Mg2+ and Zn2+ significantly enhanced both enzymatic activity and thermal stability. Additionally, notable stability was demonstrated in the presence of reducing and chaotropic agents as well as in surfactants, oxidizing agents, and organic solvents commonly found in detergent compositions. This highlights the enzyme's potential as a versatile biocatalyst, especially in detergents. Its stability and compatibility with laundry detergents matched Alcalase 2.5 L, type Dx, and the Stearothermophilus protease, used as controls. Collectively, this study investigated the potential utilization of S. aureus Pr in industrial detergents as an excellent candidate for incorporation as an additive in detergent formulations. [ABSTRACT FROM AUTHOR]

Hydrogen peroxide (H2O2) is one of the most environmentally friendly and versatile chemical oxidizing agents, with only O2 and H2O as reaction products. It is widely used in environmental protection, industrial production, and medical fields. At present, most of the industrial production of H2O2 adopts anthraquinone oxidation, but there are shortcomings such as pollution of the environment and large energy consumption. Covalent organic frameworks (COFs) are a class of porous crystalline materials formed by organic molecular building blocks connected by covalent bonds. The ordered conjugated structure of COFs not only facilitates the absorption of light energy but also promotes the transport of excited-state electrons. Therefore, the photochemical synthesis of H2O2 from water and oxygen using photocatalysts based on COFs as a green route has attracted much attention. In this review, we provide an overview of recent studies on COFs as photocatalysts and the different mechanisms involved in the photocatalytic production of hydrogen peroxide. Then, we summarize the various strategies to improve the performance. Finally, we outline the challenges and future directions of COFs in practical applications. This review highlights the potential and application prospects of COFs in the photochemical synthesis of H2O2, aiming to provide guidance for the design of COF-based catalysts and the optimization for photocatalytic production of H2O2, in order to promote scientific development and application in this field. [ABSTRACT FROM AUTHOR]

A practicable method is described for the synthesis of 3‐acyl‐pyrazolo[1,5‐a]pyridines from N‐aminopyridines and easily available enaminones via a [3+2] cycloaddition. The reactions proceed well with a broad scope, without using additive (base or oxidant). [ABSTRACT FROM AUTHOR]

Here, we report how the oxidation of carbon fibers (CFs) with H2O2 and HNO3 affects the CFs' microwave properties. The CFs were characterized by SEM and TEM, and oxygen-containing surface groups were quantified by thermal analysis methods. Treatment with H2O2 and HNO3 solutions increased the oxygen content to about 6 at% and up to 10 at%, respectively, which decreased the reflection loss and increased the transmission loss at 25.86–37.5 GHz. The microwave properties showed pronounced correlations with the concentration of HNO3 and not with H2O2, indicating that the HNO3 oxidant is more promising for microwave loss tuning. [ABSTRACT FROM AUTHOR]

In this paper, we investigate the Al2O3/GaN critical buried interface of the next generation of gallium nitride (GaN)‐based transistors using time‐of‐flight secondary ion mass spectrometry (ToF‐SIMS) and hard X‐ray photoelectron spectroscopy (HAXPES). Results highlight that gallium oxidation at this interface is enhanced when increasing the Al2O3 thickness from 3 up to 20 nm. Gallium oxidation is reduced when using both O3 and H2O as oxidant precursors, compared with only H2O during the growth of Al2O3. In addition, the O3/H2O‐based Al2O3 favors a reduction of contaminants such as hydrogen and carbon but enhances the presence of halides (Cl− and F−) at this Al2O3/GaN interface. [ABSTRACT FROM AUTHOR]

Cellulose is extracted and purified from as-received sugarcane bagasse by alkaline treatment. Then, regenerated cellulose (RC) is successfully prepared by dissolving cellulose suspension into 1:1 (v/v) of NaOH/urea mixture. The evaluation of the transformation of RC is investigated by FTIR and XRD. It is observed that the peak at the wavenumber of 1453 cm−1 is presented due to C–H stretching of RC. It is related to intramolecular hydrogen bond. The crystallinity of cellulose is transformed from cellulose I to cellulose II. Gamma-irradiation technique is employed to induce the in situ polymerization of the polypyrrole (PPy) onto RC. The irradiation doses are ranged from 10–50 kGy without the addition of an oxidizing agent. The increase of PPy content results in the enhancement of wettability and electrical conductivity. However, the percentage of crystallinity is significantly decreased. With the optimum of 5 wt % of PPy onto RC, the percent of crystallinity, the content of nitrogen, contact angle, and electrical conductivity are found to be 28.5%, 0.87 wt %, 14.4°, and 17.8 × 10–4 S·cm−1, respectively. The PPy/RC composite film is successfully developed through gamma-irradiation-induced in situ polymerization. This composite is remarkably considered as a great promise for potential candidate of bio-electrode in the near future. [ABSTRACT FROM AUTHOR]

A systematic procedure for the removal of color and chemical oxygen demand (COD) of an aqueous solutions comprising initial mixed binary azo reactive dyes (Corafix Red ME4B and Corazol Black BX), present in any proportions of initial concentrations, has been developed. It utilizes a Fenton-like advanced oxidation process (AOP) involving the activation of mixed binary oxidants as a pretreatment and a hybrid process, consisting of US cavitation and O3 based AOPs, as a post-treatment method. For the red dye, the optimum values of activator concentration, initial oxidant-ratio, initial oxidant-dosage, initial pH of initial H2O2 solution have been determined to be 100 g L−1, 3 wt% mM−1, 18:6 wt% mM−1, and 5 respectively; while, the US cavitation or O3 has been determined to be an optimum post-treatment. Similarly, for the black dye these optimum values and process are identified to be 100 g L−1, 3 wt% mM−1, 30:10 wt% mM−1, 3, and hybrid process respectively. The common optimum values of various parameters of pretreatment and a common optimum post-treatment method have been derived and experimentally demonstrated for the treatment of mixed binary dye solutions. The mechanisms responsible for decolorization and COD removal have been identified via hydroxyl and superoxide radical-trapping experiments [ABSTRACT FROM AUTHOR]

The potassium dichromate (K2Cr2O7) is mostly used as an oxidizing agent in a variety of industrial and laboratory. It poses both immediate and long-term health risks, just like any other compound containing hexavalent chromium. Therefore, its adsorption process on the surface of a different metal oxides of PbO and MgO nanoparticles is thoroughly investigated in this work. Both structural and optical properties have been investigated for these metal oxides using XRD, HRTEM and UV vis spectroscopy. The XRD diffraction peaks confirmed the phases of both PbO and MgO NPs. Moreover, the crystallinity of PbO and MgO is 93,63 % and 95.25 %, respectively. The present metal oxides showed irregular shape such as spherical like shape and Quasi-spherical or rod- like shapes for PbO and MgO NPs. According to the results of the adsorption studies, The PbO NPs shows a high adsorption efficiency of 70 % towards potassium dichromate. The present results illustrated that both metal oxides may be used as an adsorbent to break down Potassium dichromate. [ABSTRACT FROM AUTHOR]

The paper presents an analysis of the performance of a Proton Exchange Membrane (PEM) fuel cell, which is equipped with a flow field design featuring dual inlets and outlets, while operating under conditions of excess stoichiometry. These experiments were conducted using a fuel cell system connected to a station that allowed for the precise adjustment of gas flow rates. During the initial phase of experimentation, various proportions of excess oxygen were systematically applied, while maintaining constant hydrogen flow rates of 80 mL/min and 100 mL/min. Particularly noteworthy, for the case of a 100 mL/min hydrogen gas flow rate and the optimized excess oxygen proportion of 150%, further experiments were undertaken to ascertain the ideal humidification conditions. The outcomes of these experiments revealed that a hydrogen gas flow rate of 100 mL/min consistently outperformed the 80 mL/min flow rate in terms of fuel cell performance. Moreover, it was observed that the introduction of excess oxygen significantly improved performance, up to a 50% oxygen proportion for the 80 mL/min hydrogen flow rate and up to a 150% proportion for the 100 mL/min hydrogen flow rate. One intriguing observation pertained to the influence of humidification. Specifically, it was found that the utilization of a humidification temperature of 100°C, or the absence of humidification altogether, resulted in notably diminished power output. In contrast, intermediate humidification temperatures of 60°C, 70°C, 80°C, and 90°C consistently yielded identical maximum power points (MPP) when combined with a 150% excess oxygen supply and a hydrogen flow rate of 100 mL/min. The twin inlet-twin outlet flow field provides a slight advantage over the conventional serpentine flow field in the overall analysis. [ABSTRACT FROM AUTHOR]

Liquid-liquid reactions play a significant role in organic synthesis. However, control of the phase interface between incompatible two-phase liquids remains challenging. Moreover, separating liquid acid, base and oxidants from the reactor takes a long time and high cost. To address these issues, we draw inspiration from the structure and function of cells in living organisms and develop a biomimetic 3D-printed cellular reactor. The cellular reactor houses an aqueous phase containing the catalyst or oxidant while immersed in the organic phase reactant. This setup controls the distribution of the phase interface within the organic phase and increases the interface area by 2.3 times. Notably, the cellular reactor and the aqueous phase are removed from the organic phase upon completing the reaction, eliminating additional separation steps and preventing direct contact between the reactor and acidic, alkaline, or oxidizing substances. Furthermore, the cellular reactor offers the advantages of digital design feasibility and cost-effective manufacturing. This study presents a 3D-printed cellular reactor enhancing liquid-liquid reactions by increasing contact area without extra additives. It securely contains two incompatible liquids, facilitating direct phase separation. [ABSTRACT FROM AUTHOR]

In order to address the issues of slow degradation rate, narrow pH applicability, and poor regeneration of zero-valent transition metal catalysts during the degradation of hydroxypropyl guar gum (HPG), templated hydrotalcite with hierarchical pores was established and hydrogen peroxide-persulfate dual oxidant was used in this work. The results demonstrate that zero-valent copper, supported on multilevel porous hydrotalcites synthesized using worm-like micellar soft templates within a wide pH range from 3 to 11, achieved a viscosity reduction rate of up to 80.92% for HPG within 25 min and a COD removal efficiency of 96.37% after 120 min. And high degradation efficiency, 81.08%, can be obtained even after five recycles at pH 7. Furthermore, free radical quenching experiments, as well as XRD, BET, and SEM characterization, confirm that the degradation of HPG is attributed to the collaborative activation of SO4−·, ·O2−, 1O2, and ·OH radicals in the H2O2–Na2S2O8 dual oxidant, which provide new insights for the degradation of oilfield pollutants. [ABSTRACT FROM AUTHOR]

This paper describes a new active method of controlling the position of the burning surface of a solid fuel strand in an opposed-flow burner experiment. This method is designed to avoid biases to the combustion process introduced by retaining wires and to avoid experimental delays caused by wire failures. Regression rates are presented for hydroxyl-terminated polybutadiene fuel strands burning in various oxidizer streams. The active control method uses a control loop composed of a diode laser, a photodiode, and a stepper motor. For comparison, tests were also performed using the commonly used passive control method of spring-loading the fuel against a retaining wire. This active control method can only be used at high values of oxidizer mass flux; at low mass flux, soot accumulation obstructs the laser beam. In passive control tests, the retaining wire conducts heat from the flame into the fuel and increases regression rate. The presence of the wire also modifies the extinction limits of the flame. A model was developed for regression rate as a function of oxidizer mass flux, oxidizer composition, and retaining wire diameter. This model can be used to correct future regression rate data for the bias introduced by retaining wires. [ABSTRACT FROM AUTHOR]