Retraction of "Research and Analysis of Insulating Gas in Unified Test Conditions".

[This retracts the article DOI: 10.1021/acsomega.1c05760.].

Research and Analysis of Insulating Gas in Unified Test Conditions.

In order to study the insulation mechanism of SF6 substitute gas, it is suggested to calculate the dielectric strength of insulating gas from the molecular structure. The dielectric strength of a typical gas is modeled by a power frequency breakdown test under a uniform electric field. The molecular parameters of insulating gases are calculated by the density functional theory method, and the effect of molecular structure parameters on the breakdown voltage of power frequency is studied. Based on the molecular structure parameters, which are closely related to the breakdown voltage of power frequency, a model of pressure and distance variation of AC breakdown voltage of insulating gas is established. The breakdown voltages of insulating gases (CF3SO2F) are also derived from the proposed model. The calculated breakdown voltage of power frequency of two gases is compared with the experimental value. The average error is just 2.6%. This model provides a basis for the future search for potential alternative insulating gases.

Efficient Red Thermally Activated Delayed Fluorescence Emitters Based on a Dibenzonitrile-Substituted Dipyrido[3,2-a:2',3'-c]phenazine Acceptor.

How to construct efficient red-emitting thermally activated delayed fluorescence (TADF) materials is a challenging task in the field of organic light-emitting diodes (OLEDs). Herein, an electron acceptor moiety, 3,6-DCNB-DPPZ, with high rigidity and strong acceptor strength was designed by introducing two cyanobenzene groups into the 3,6-positions of a dipyrido[3,2-a:2',3'-c]phenazine unit. A red-emitting compound, 3,6_R, has been designed and synthesized by combining the rigid acceptor unit with two triphenylamine donors. Due to high molecular rigidity and strong intramolecular charge transfer characteristic in donor-acceptor-donor skeleton, 3,6_R exhibited a red emission with a high photoluminescence quantum yield of 86% and distinct TADF nature with short delayed fluorescence lifetime of about 1 microsecond. Accordingly, the OLED using 3,6_R as the guest emitter gained a high external quantum efficiency of 12.0% in the red region with an electroluminescence peak of 619 nm and favorable Commission Internationale de l'Eclairage coordinates of (0.62, 0.38).

Synthesis and dielectric properties of the eco-friendly insulating gas thiazyl trifluoride.

Sulfur hexafluoride (SF6), which is known as a superior electrically insulating and arc-quenching medium, plays a decisive role in the modern transmission and distribution network of electric energy, especially in high-voltage power networks. However, the ever-increasing usage of SF6 also leads to the continuous escalation of atmospheric SF6 levels, which is considered to be the main cause of the greenhouse effect. To decrease this environmental impact, eco-friendly alternatives to SF6 have been researched for decades. To date, no significant success has been made regarding replacement gases for transmission networks. Some potential alternatives have comparatively lower global warming potential (GWP) but involve technical trade-offs. Thiazyl trifluoride, which has some excellent chemical and electric properties, is a novel substitution candidate for SF6. In this article, an efficient synthetic route starting from sulfur monochloride and followed by ammonization and fluorination was proposed. The structures of the intermediates and the target products were determined by X-ray diffraction (XRD), infrared spectroscopy (IR), and gas chromatography-mass spectrometry (GC-MS). The effects of some determining factors on the yield and purity, including the molar ratio of the reactants, recrystallization conditions and condensation temperature, were also investigated. The results showed that the overall yield of thiazyl trifluoride was approximately 25%, while the purity could be up to 90.6% under optimal conditions.

Electrodeposition of nickel in air- and water-stable 1-butyl-3-methylimidazolium dibutylphosphate ionic liquid.

Nickel coating was obtained by potentiostatic electrodeposition in 1-butyl-3-methylimidazolium diethylphosphate ionic liquid without any additive. Further, cyclic voltammetry (CV) tests were used to investigate the electrochemical behaviour of Ni2+ in the ionic liquid, revealing that the electrodeposition of nickel in this ionic liquid is an irreversible process. It was revealed that the diffusion of Ni2+ is a rate-determining step in the electrodeposition process. Further, the influence of dissolved water and applied voltage on electrodeposition were also studied using scanning electron microscopy (SEM).

pH-Responsive Pickering emulsion stabilized by polymer-coated silica nanoaggregates and applied to recyclable interfacial catalysis.

We first synthesized a diblock copolymer poly[tert-butyl methacrylate]-b-poly[3-(trimethoxysilyl)propyl methacrylate] (PtBMA-b-PTMSPMA) through reversible addition-fragmentation chain transfer (RAFT) living radical polymerization and grafted it onto fumed silica by converting the PTMSPMA segment to silanol and the PtBMA segment to polymethylacrylic acid (PMAA) in the presence of trifluoroacetic acid in order to obtain PMAA brush-coated silica nanoaggregates P-Si. TEM, DLS, FTIR, and TGA results confirmed the successful modification of the starting materials. The nanoaggregates flocculated and stabilized a toluene-in-water Pickering emulsion at low pH, while the nanoaggregates were well dispersed in water and broke the emulsion under both neutral and basic conditions. Alternatively, the addition of acid/base induced emulsification/demulsification cycles that were sustained for several cycles. Moreover, when the P-Si was mixed with Rh-loaded silica, Rh-Si, the mixture had the same pH-responsive Pickering emulsion behavior as the single P-Si. This Pickering emulsion system can be used in the biphasic interfacial catalytic hydrogenation of olefins and had excellent yields under a hydrogen atmosphere. The yield of Pickering emulsion catalysis rapidly reached more than 99% in 3 h, while that of the demulsified mixture failed to reach 20% in 4 h, which verified the promotion of catalysis by the Pickering emulsion. Base-induced demulsification can be used to separate the products and recycle the catalyst. This pH-responsive Pickering emulsion catalytic system was capable of several cycles of reuse, and there was no significant decrease in catalytic efficiency even after eight cycles.

Electrochemical degradation of dye on TiO2 nanotube array constructed anode.

A high oxygen evolution potential (2.6V) and conductivity of Ti/TiO2 NTs/Ta2O5-PbO2 anode was fabricated by mixed metal oxide. A well-aligned TiO2 nanotubes was successfully prepared by using 1-butyl-3-methylimidazolium tetrafluoroborate as the electrolyte. The surface structure of anodes were characterized by scanning electron microscope, X-ray diffraction and energy dispersive X-ray spectroscopy. During the electrochemical degradation experiments, the effects of different anodes, current density, initial pH value and concentration were discussed. The results showed that co-doped Ta2O5 coating is an effective method to improve the surface morphology and the electrochemical characterization of Ti/TiO2 NTs/PbO2. At the initial pH value of 3 and current density of 12 mA cm-2, the removal rates of Acid Orange 7 and total organic carbon with Ti/TiO2 NTs/Ta2O5-PbO2 anode were almost 100% and 98.3%. Comparing with Ti/PbO2 anode at the same charge consumption (3 A h L-1), the instantaneous current efficiency of the Ti/TiO2 NTs/Ta2O5-PbO2 anode and Ti/TiO2 NTs/PbO2 anode increased by 40.0% and 27.1%, respectively. The highest rate of k.OH on Ti/TiO2 NTs/Ta2O5-PbO2 anode was 12.4 µmol (L min)-1. The organic dyes are oxidized into CO2 and H2O by .OH radical. The reaction process and mechanism during the electrochemical degradation were discussed.

Novel and efficient synthesis of insulating gas- heptafluoroisobutyronitrile from hexafluoropropylene.

A novel and efficient preparation route of insulating gas-heptafluoroisobutyronitrile was developed. The synthetic route involved halogen-exchange fluorination, decomposition of bis-(perfluoroisopropyl) ketone and dehydration reaction. Overall, the desired compound was produced without the use of extremely toxic and expensive substances. Structures of the as-obtained products were determined by 19F NMR, 13C NMR, IR and GC-MS. The effects of several variables on reaction yield including nature of potassium fluoride, the catalyst dosage, temperature, solvent and molar ratio of raw materials were all investigated. The results indicated that the total yield of heptafluoroisobutyronitrile could reach 42% from original materials under optimal conditions and the mechanism of the reaction was proposed.

A novel and efficient synthetic route to perfluoroisobutyronitrile from perfluoroisobutyryl acid.

A novel synthetic route to perfluoroisobutyronitrile from perfluoroisobutyryl acid which has mild conditions and low toxicity is described. This study introduces detailed synthetic protocols and characterization including GC-MS, 13C NMR and 19F NMR spectroscopy of perfluoroisobutyryl acid, perfluoroisobutyryl chloride, perfluoroisobutyl amide and perfluoroisobutyronitrile. Besides, this route is superior to the established patent and shows potential application in high voltage electrical equipment.

Large-Scale Synthesis of Metal-Ion-Doped Manganese Dioxide for Enhanced Electrochemical Performance.

One-dimensional (1D) MnO2 was widely applied in areas of enzyme biosensors, industrial sieves, and energy storage materials owing to its excellent thermal, optical, magnetic, and chemical features. However, its practical application into energy storage devices is often hindered by the bad electronic conductivity (from 10(-5) to 10(-6) S cm(-1)). As is widely known, doping with hetero elements is an efficient way to enhance the electronic conductivity of metal oxides. Herein, a novel and simple molten-salt method is developed to achieve a large-scale preparation of 1D MnO2 nanowires. Such an approach also realizes the easy tuning of electrical properties through doping with different transition metal ions. On the basis of first-principle calculation as well as four-probe measurement, we determined that the conductivity of the doped MnO2 nanowires can be promoted efficiently by utilizing such protocol. Meanwhile, a possible doping route is discussed in detail. As a result, a superior electrochemical performance can be observed in such metal ions (M(+))-doped nanowires. Such high-quality M(+)-doped MnO2 nanowires can satisfy a broad range of application needs beyond the electrochemical capacitors.

Preparation and characterization of TiO2-regenerated cellulose inorganic-polymer hybrid membranes for dehydration of caprolactam.

Novel membrane of inorganic-polymer hybrid membrane was prepared by incorporation of the nano-TiO2 into regenerated cellulose (RC). The resulting membrane was characterized by AFM, SEM, and XRD. TiO2 particles formed on the surface and in the interior of the hybrid membrane due to the TiO2 conglomeration, and the surface roughness of the hybrid membrane increased linearly with increasing TiO2 content. The membrane was tested for their ability to separate caprolactam-water mixtures by pervaporation. Among all the prepared membranes, RC-TiO2 inorganic-polymer hybrid membrane containing 5wt.% TiO2 exhibited the good pervaporation performance with a flux of 1787.3gm-2h-1 and separation factor of 55091.7 at 328K for 50wt.% caprolactam. Besides, the normalized permeation fluxes in terms of water permeance, caprolactam permeance and selectivity were also introduced to evaluate the membranes performance. The activation energies were calculated using Arrhenius equation.

Relating organic fouling of reverse osmosis membranes to adsorption during the reclamation of secondary effluents containing methylene blue and rhodamine B.

Dyes fouling of reverse osmosis (RO) membranes and its relation to adsorption had been investigated by using a crossflow RO filtration setup. Methylene blue (MB) and rhodamine B (RB) were used as model organic foulants. The calculated amount of the irreversible sorption was related to the irreversible flux decline. The characteristic fouling kinetics was accounted by Langmuir-Hinshelwood (L-H) kinetics model for initial fouling, with the fouling rate constant k=0.0556µm s(-1)min(-1) and k=0.0181µm s(-1)min(-1) for MB and RB fouling RO membrane CPA2, respectively. And the subsequent fouling was attributed to the growth of a dye cake. A remarkable correlation was obtained between the quantified irreversible sorption and irreversible flux decline under the solution chemistries investigated. In the presence of divalent cation, the extent of flux decline was related to the competition model.

Candida tropicalis: characterization of a strain capable of degrading high concentrations of phenol.

PURPOSE OF WORK: This study was to demonstrate the degradation effectiveness and application potential of Candida tropicalis JH8. A phenol-degrading yeast was isolated from activated sludge and was identified as C. tropicalis. It used phenol as the sole source of carbon at up to 1,800 mg l(-1). The optimal conditions for phenol degradation were pH 6 at 37 °C with a 2% (v/v) inoculum. Complete degradation of 1,800 mg phenol l(-1) was achieved after 62 h.

Biodegradation of phenol at high concentration by a novel fungal strain Paecilomyces variotii JH6.

A novel phenol-degrading filamentous fungus, strain JH6, was isolated from activated sludge and identified as a member of Paecilomyces variotii based on standard morphological and phylogenetic analysis. The degradation assays suggested that the strain was able to utilize phenol as the sole source of carbon and energy at concentrations up to 1800 mg/l. The strain exhibited optimum phenol degradation performance with the addition of 100 mg/l glucose at pH 5, 37°C. Haldane's model could be fitted to the growth kinetics data well over a wide range of initial phenol concentrations (100-1800 mg/l), with kinetic values µ(max)=0.312 h(-1), K(s)=130.4 mg/l, and K(i)=200 mg/l. The decay coefficient was found to be 0.0073 h(-1). Complete phenol degradation by strain JH6 could be achieved in the presence of other toxicants, such as m-cresol and quinoline, which were often found in the real phenol-containing wastewater.