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Angewandte Chemie (International Ed. in... May 2022Oxidase-type oxidation is an attractive strategy in organic synthesis due to the use of O as the terminal oxidant. Organic photocatalysis can effect metal-free oxidase...
Oxidase-type oxidation is an attractive strategy in organic synthesis due to the use of O as the terminal oxidant. Organic photocatalysis can effect metal-free oxidase chemistry. Nevertheless, current methods are limited in reaction scope, possibly due to the lack of suitable photocatalysts. Here we report an isoquinoline-derived diaryl ketone-type photocatalyst, which has much enhanced absorption of blue and visible light compared to conventional diaryl ketones. This photocatalyst enables dehydrogenative cross-coupling of heteroarenes with unactivated and activated alkanes as well as aldehydes using air as the oxidant. A wide range of heterocycles with various functional groups are suitable substrates. Transient absorption and excited-state quenching experiments point to an unconventional mechanism that involves an excited state "self-quenching" process to generate the N-radical cation form of the sensitizer, which subsequently abstracts a hydrogen atom from the alkane substrate to yield a reactive alkyl radical.
Topics: Alkanes; Catalysis; Hydrogen; Isoquinolines; Ketones; Oxidants; Oxidoreductases
PubMed: 35253971
DOI: 10.1002/anie.202202649 -
Chemosphere Sep 2023Tetracycline (TC) and Oxytetracycline (OTC) are common antibiotics increasingly detected in the environment, posing a potential risk to human and aquatic lives. Although...
Non-thermal plasma activated peroxide and percarbonate for tetracycline and oxytetracycline degradation: Synergistic performance, degradation pathways, and toxicity evaluation.
Tetracycline (TC) and Oxytetracycline (OTC) are common antibiotics increasingly detected in the environment, posing a potential risk to human and aquatic lives. Although conventional methods such as adsorption and photocatalysis are used for the degradation of TC and OTC, they are inefficient in removal efficiency, energy yield, and toxic byproduct generation. Herein, a falling-film dielectric barrier discharge (DBD) reactor coupled with environmentally friendly oxidants (hydrogen peroxide (HPO), sodium percarbonate (SPC), and HPO + SPC) was applied, and the treatment efficiency of TC and OTC was investigated. Experimental results showed that moderate addition of the HPO and SPC exhibited a synergistic effect (SF > 2), significantly improving the antibiotic removal ratio, total organic removal ratio (TOC), and energy yield by more than 50%, 52%, and 180%, respectively. After 10 min of DBD treatment, the introduction of 0.2 mM SPC led to a 100% antibiotic removal ratio and a TOC removal of 53.4% and 61.2% for 200 mg/L TC and 200 mg/L OTC, respectively. Also, 1 mM HPO dosage led to 100% antibiotic removal ratios after 10 min of DBD treatment and a TOC removal of 62.4% and 71.9% for 200 mg/L TC and 200 mg/L OTC, respectively. However, the DBD + HPO + SPC treatment method had a detrimental effect on the performance of the DBD reactor. After 10 min of DBD plasma discharge, the removal ratios for TC and OTC were 80.8% and 84.1%, respectively, when 0.5 mM HPO + 0.5 mM SPC was added. Moreover, principal component and hierarchical cluster analysis confirmed the differences between the treatment methods. Furthermore, the concentration of oxidant-induced in-situ generated ozone and hydrogen peroxide were quantitatively determined, and their indispensable roles during the degradation process were established via radical scavenger tests. Finally, the synergetic antibiotic degradation mechanisms and pathways were proposed, and the toxicities of the intermediate byproducts were evaluated.
Topics: Humans; Oxytetracycline; Peroxides; Hydrogen Peroxide; Water Pollutants, Chemical; Anti-Bacterial Agents; Tetracycline; Heterocyclic Compounds; Oxidants
PubMed: 37330069
DOI: 10.1016/j.chemosphere.2023.139246 -
Water Research Sep 2022As a feed additive, p-arsanilic acid (p-ASA) is hardly metabolized in animal bodies and is excreted chemically unchanged via feces and urine, which can be transformed...
As a feed additive, p-arsanilic acid (p-ASA) is hardly metabolized in animal bodies and is excreted chemically unchanged via feces and urine, which can be transformed into more toxic inorganic arsenic species and other organic by-products upon degradation in the aquatic environment. In this study, UV-LED/persulfate (PS)/Fe(Ⅲ) and UV-LED/peroxymonosulfate (PMS)/Fe(Ⅲ) processes were developed to remove p-ASA and immobilize the formed inorganic arsenic via tuning solution pH. UV-LED/PMS/Fe(Ⅲ) (90.8%) presented the best performance for p-ASA degradation at pH 3.0, and the p-ASA degradation in these processes both followed the pseudo-first-order kinetics. The ∙OH played the major role in UV-LED/PS/Fe(Ⅲ) and UV-LED/PMS/Fe(Ⅲ) systems. Solution pH greatly affected the p-ASA degradation and the maximum removal can be achieved at pH 3.0 due to the presence of more Fe(OH)(HO). The dosages of Fe(III) and PMS (PS), SO and HCO significantly influenced the performance of p-ASA oxidation, while HA, Cl and NO slightly affected the p-ASA degradation. According to quantum chemical calculation, radical addition on the C atom in the C-As bond of p-ASA was corroborated to be the dominant reaction pathway by SO∙ and ∙OH. Additionally, the reactive sites and reasonable degradation pathways of p-ASA were proposed based on DFT calculation and HPLC/MS analysis. The release of inorganic arsenic in both processes can be effectively immobilized and the toxicity of the reaction solution dramatically reduced by adjusting solution pH to 6.0. UV-LED/PMS/Fe(Ⅲ) process was found to be more cost-effective than UV-LED/PS/Fe(Ⅲ) process at the low oxidant dosages.
Topics: Animals; Arsanilic Acid; Arsenates; Arsenic; Ferric Compounds; Oxidants; Oxidation-Reduction; Peroxides; Water Pollutants, Chemical
PubMed: 35998556
DOI: 10.1016/j.watres.2022.118989 -
International Journal of Environmental... Mar 2023NO is a greenhouse gas and a candidate oxidant. Volatile organic pollutants (VOCs) have caused great harm to the atmospheric ecological environment. Developing the...
NO is a greenhouse gas and a candidate oxidant. Volatile organic pollutants (VOCs) have caused great harm to the atmospheric ecological environment. Developing the technique utilizing NO as the oxidant to oxidize VOCs to realize the collaborative purification has significant importance and practical value for NO emission control and VOC abatement. Therefore, the study of NO catalytic oxidation of tert-butanol based on zeolite catalysts was carried out. A series of molecular sieves, including FER, MOR, ZSM-5, Y, and BEA, were selected as the catalyst objects, and the 1.5% wt Fe and Co were, respectively, loaded on the zeolite catalysts via the impregnation method. It was found that the catalytic performance of BEA was the best among the molecular sieves. Comparing the catalytic performance of Fe-BEA under different load gradients (0.25~2%), it was found that 1.5% Fe-BEA possessed the best catalytic activity. A series of characterization methods showed that Fe content in 1.5% Fe-BEA was the highest, and more active sites formed to promote the catalytic reaction. The α-O in the reaction eventually oxidized tert-butanol to CO over the active site. The Co mainly existed in the form of Co cations over Co-BEA samples; the 2% Co-BEA possessing higher amounts of Co exhibited the highest activity among the prepared Co-BEA samples.
Topics: tert-Butyl Alcohol; Zeolites; Oxidants; Oxidation-Reduction
PubMed: 36981811
DOI: 10.3390/ijerph20064902 -
Environmental Science & Technology Apr 2024Formation of highly oxygenated molecules (HOMs) such as organic peroxides (ROOR, ROOH, and HO) is known to degrade food and organic matter. Gas-phase unimolecular...
Formation of highly oxygenated molecules (HOMs) such as organic peroxides (ROOR, ROOH, and HO) is known to degrade food and organic matter. Gas-phase unimolecular autoxidation and bimolecular RO + HO/RO reactions are prominently renowned mechanisms associated with the formation of peroxides. However, the reaction pathways and conditions favoring the generation of peroxides in the aqueous phase need to be evaluated. Here, we identified bulk aqueous-phase ROOHs in varying organic precursors, including a laboratory model compound and monoterpene oxidation products. Our results show that formation of ROOHs is suppressed at enhanced oxidant concentrations but exhibits complex trends at elevated precursor concentrations. Furthermore, we observed an exponential increase in the yield of ROOHs when UV light with longer wavelengths was used in the experiment, comparing UVA, UVB, and UVC. Water-soluble organic compounds represent a significant fraction of ambient cloud-water components (up to 500 μM). Thus, the reaction pathways facilitating the formation of HOMs (i.e., ROOHs) during the aqueous-phase oxidation of water-soluble species add to the climate and health burden of atmospheric particulate matter.
Topics: Peroxides; Hydrogen Peroxide; Particulate Matter; Oxidants; Water; Aerosols
PubMed: 38578220
DOI: 10.1021/acs.est.3c01162 -
Nature Communications Jul 20221,2-Amino oxygenation of alkenes has emerged as one of the most straightforward synthetic methods to produce β-amino alcohols, which are important organic building...
1,2-Amino oxygenation of alkenes has emerged as one of the most straightforward synthetic methods to produce β-amino alcohols, which are important organic building blocks. Thus, a practical synthetic strategy for 1,2-amino oxygenation is highly desirable. Here, we reported an electro-oxidative intermolecular 1,2-amino oxygenation of alkenes with hydrogen evolution, removing the requirement of extra-oxidant. Using commercial oxygen and nitrogen sources as starting materials, this method provides a cheap, scalable, and efficient route to a set of valuable β-amino alcohol derivatives. Moreover, the merit of this protocol has been exhibited by its broad substrate scope and good application in continuous-flow reactors. Furthermore, this method can be extended to other amino-functionalization of alkenes, thereby showing the potential to inspire advances in applications of electro-induced N-centered radicals (NCRs).
Topics: Alkenes; Catalysis; Hydrogen; Oxidants; Oxidation-Reduction
PubMed: 35908027
DOI: 10.1038/s41467-022-32084-8 -
Water Research Sep 2020Since the early 2000s, dual-frequency ultrasound (DFUS) has received much attention for synergistically enhanced elimination of organic pollutants and pathogenic... (Review)
Review
Since the early 2000s, dual-frequency ultrasound (DFUS) has received much attention for synergistically enhanced elimination of organic pollutants and pathogenic microorganisms from water. In the present review, we have surveyed recent developments in acoustic physics to elucidate the mechanism of synergistic effect under exposure of aqueous media to DFUS. Briefly, the nonlinear dynamics of microbubbles upon DFUS exposure produces additional frequencies, such as harmonics, subharmonics, ultraharmonics and combination frequencies. These increase the probability of bubbles collapse, thereby enhancing cavitation and generating more reactive oxygen species (ROS) for advanced oxidation processes (AOPs). Further, literature data on ROS generation, chemical degradation and microbial inactivation in aqueous media through DFUS alone and DFUS-based AOPs (involving oxidants or catalysts) have been discussed. In this regard, optimal frequency combination, sonoreactor type and transducer arrangement appear to be key parameters for achieving a high synergistic effect. Strengths and shortcomings of DFUS to water treatment and disinfection have been identified and future research directions have been proposed. Though most studies were conducted on pure (matrix-free) aqueous solutions, these AOPs could be applicable for treating real waters.
Topics: Disinfection; Oxidants; Oxidation-Reduction; Water Pollutants, Chemical; Water Purification
PubMed: 32619682
DOI: 10.1016/j.watres.2020.116016 -
Environmental Research Sep 2022For the first time, two new kinds of inorganic-organic hybrid nanomaterials (BiWO@rGO and Cu-WO@rGO) were fabricated by simple hydrothermal treatment and employed for...
Development of reduced graphene oxide-supported novel hybrid nanomaterials (BiWO@rGO and Cu-WO@rGO) for green and efficient oxidative desulfurization of model fuel oil for environmental depollution.
For the first time, two new kinds of inorganic-organic hybrid nanomaterials (BiWO@rGO and Cu-WO@rGO) were fabricated by simple hydrothermal treatment and employed for green and efficient oxidative desulfurization of real fuel. The characterization of newly synthesized nanocomposites was performed by SEM, EDX, P-XRD, FT-IR and TGA. SEM and XRD analyses revealed well decoration of dopants (Cu-WO and Bi-WO) on the surface of rGO with a crystallite size of <50 nm. The catalytic activity of both nanocatalysts was examined for model (dibenzothiophene) and real fuel (kerosene and diesel) by oxidative desulfurization route. Experimental findings revealed a high efficiency of over 90% under optimal reaction conditions of 0.1 g catalyst, 1 mL of oxidant, and 100 mg/L after 120 min at 30 °C. The major factors affecting desulfurization efficiency (time, temperature, catalyst amount, dibenzothiophene (DBT) concentration and amount of oxidant) and kinetic studies were described. The DBT removal via oxidative desulfurization followed pseudo first-order kinetics with an activation energy of 14.57 and 16.91 kJ/mol for Cu-WO@rGO and BiWO@rGO, respectively. The prepared catalysts showed promising reusability for the ODS process up to 5 times with no significant decrease in efficiency. In conclusion, the findings confirm the robustness of newly prepared nanocomposite for efficient production of sulfur-free oil.
Topics: Fuel Oils; Graphite; Kinetics; Nanocomposites; Oxidants; Oxidative Stress; Spectroscopy, Fourier Transform Infrared
PubMed: 35351451
DOI: 10.1016/j.envres.2022.113160 -
The Science of the Total Environment Oct 2021In recent years, there has been increasing interest in using of advanced oxidation processes in water and wastewater decontamination. As a new oxidants peracids, mainly... (Review)
Review
Peracids - New oxidants in advanced oxidation processes: The use of peracetic acid, peroxymonosulfate, and persulfate salts in the removal of organic micropollutants of emerging concern - A review.
In recent years, there has been increasing interest in using of advanced oxidation processes in water and wastewater decontamination. As a new oxidants peracids, mainly peracetic acid (PAA) and peracid salts, i.e. peroxymonosulfate (PMS) and persulfate (PS) are used. The degradation process of organic compounds takes place with the participation of radicals, including hydroxyl (OH) and sulfate (SO) radicals derived from the peracids activation processes. Peracids can be activated in homogeneous systems (UV radiation, d-electron metal ions, e.g. Fe, Co, Mn, base, ozonolysis, thermolysis, radiolysis), or using heterogeneous activation (metals with zero oxidation state, metal oxides, quinones, activated carbon, semiconductors). As a result of oxidation, products of a lower mass than the parent compounds, less toxic, and more susceptible to biodegradation are formed. An important task is to investigate the effect of the peracid activation method and matrix composition on the efficiency of contamination removal. The article presents the latest information about the application of peracids in the removal of organic micropollutants of emerging concern (mainly focuses on endocrine disrupted compounds). The most important information on peracetic acid, peroxymonosulfate and persulfate salts, and methods of their activation are presented. Current uses of these oxidants in organic micropollutants removal are also described. Information was collected on the factors influencing the oxidation process and the effectiveness of pollutant removal. This paper compares PAA, PMS and PS-based processes for the first time in terms of kinetics and efficiency.
Topics: Oxidants; Oxidation-Reduction; Peracetic Acid; Peroxides; Salts; Water Pollutants, Chemical
PubMed: 34380254
DOI: 10.1016/j.scitotenv.2021.148195 -
Molecules (Basel, Switzerland) Feb 2020The development of sustainable processes and products through innovative catalytic materials and procedures that allow a better use of resources is undoubtedly one of... (Review)
Review
The development of sustainable processes and products through innovative catalytic materials and procedures that allow a better use of resources is undoubtedly one of the most significant issues facing researchers nowadays. Environmental and economically advanced catalytic processes for selective oxidation of alcohols are currently focused on designing new catalysts able to activate green oxidants (dioxygen or peroxides) and applying unconventional conditions of sustainable significance, like the use of microwave irradiation as an alternative energy source. This short review aims to provide an overview of the recently (2015-2020) discovered homogeneous aerobic and peroxidative oxidations of primary and secondary alcohols catalyzed by copper complexes, highlighting new catalysts with potential application in sustainable organic synthesis, with significance in academia and industry.
Topics: Alcohols; Catalysis; Copper; Green Chemistry Technology; Humans; Microwaves; Molecular Structure; Oxidants; Oxidation-Reduction; Oxygen; Peroxides
PubMed: 32050493
DOI: 10.3390/molecules25030748