Elimination Of Chlorine Research Articles

Stabilization of Organic Cations in Lead Halide Perovskite Solar Cells Using Phosphine Oxides Derivatives.

Preventing ion migration in perovskite photovoltaics is key to achieving stable and efficient devices. The activation energy for ion migration is affected by the chemical environment surrounding the ions. Thus, the migration of organic cations in lead halide perovskites can be mitigated by engineering their local interactions, for example through hydrogen bonding. Ion migration also leads to ionic losses via interfacial reactions. Undesirable reactivities of the organic cations can be eliminated by introducing protecting groups. In this work, we report bis(2-oxo-3-oxazolidinyl) phosphinic chloride (BOP-Cl) as a perovskite ink additive with the following benefits: (1) The phosphoryl and two oxo groups form six-membered intermolecular hydrogen-bonded rings with the formamidinium cation (FA), mitigating ion migrations. (2) The hydrogen bonding reduces the electrophilicity of the ammonium protons by donating electron density, therefore reducing its reactivity with the surface oxygen on the metal oxide. Furthermore, the molecule can react to form a protecting group on the nucleophilic oxygen at the tin oxide transport layer surface through the elimination of chlorine. As a result, we achieve perovskite solar cells with an efficiency of 25.0% and improved MPP stability T93 = 1200 h at 40-45 °C compared to a control device (T86 = 550 h). In addition, we show a negative correlation between the strength of hydrogen bonding of different phosphine oxide derivatives to the organic cations and the degree of metastable behavior (e.g., initial burn-in) of the device.

Characterization of the microplastic photoaging under the action of typical salt ions of biological nitrogen removal processes

Microplastics (MPs) are one of the most prevalent and diverse contaminants, and wastewater treatment plants are significant MP aggregators. Controlling the pollution caused by microplastics requires an understanding of how they age. The properties of the MPs photoaging process under the influence of salt ions typical of biological nitrogen elimination processes were disclosed in this work. The aging process of polyvinyl chloride microplastics (PVC-MPs) was greatly slowed down by greater HCO3− and NO2− concentrations, according to a comparison of the carbonyl index changes that occurred during photoaging. The carbonyl index had a negative correlation with the thermal stability of the photo-aged PVC-MPs, and aging accelerated the elimination of chlorine from the water. The samples were aged by UV radiation after 36 h at 40 °C, and the amount of chlorine eliminated was 10.13 times greater than that of the original MPs samples. It was discovered that the leachate concentration of aged MPs dramatically increased with decreasing particle size and was positively connected with the level of aging by comparing the concentration of leachate for two particle sizes (1 mm and 100 m). Photoaging caused MPs to become rougher, which in turn improved the NO3−-N, NH4+-N, and NO2−-N adsorption by PVC-MPs.

Site- and enantioselective cross-coupling of saturated N-heterocycles with carboxylic acids by cooperative Ni/photoredox catalysis

Site- and enantioselective cross-coupling of saturated N-heterocycles and carboxylic acids—two of the most abundant and versatile functionalities—to form pharmaceutically relevant α-acylated amine derivatives remains a major challenge in organic synthesis. Here, we report a general strategy for the highly site- and enantioselective α-acylation of saturated N-heterocycles with in situ-activated carboxylic acids. This modular approach exploits the hydrogen-atom-transfer reactivity of photocatalytically generated chlorine radicals in combination with asymmetric nickel catalysis to selectively functionalize cyclic α-amino C−H bonds in the presence of benzylic, allylic, acyclic α-amino, and α-oxy methylene groups. The mild and scalable protocol requires no organometallic reagents, displays excellent chemo-, site- and enantioselectivity, and is amenable to late-stage diversification, including a modular synthesis of previously inaccessible Taxol derivatives. Mechanistic studies highlight the exceptional versatility of the chiral nickel catalyst in orchestrating (i) catalytic chlorine elimination, (ii) alkyl radical capture, (iii) cross-coupling, and (iv) asymmetric induction.

Spontaneous Release of Metalloradicals and Coordinatively Unsaturated Species in Asymmetric Iridium Dimers to Promote C-N Bond Formation

An unusual iridium dimer 1, [(4-cpbo)Ir(μ-Cl)(μ-O)Ir(4-cpbo)] (4-cpbo = 4-chlorophenylbenzoxazolato-N,C2), was obtained by the oxidative addition of oxygen and reductive elimination of chlorine from a precursor [(4-cpbo)2Ir(μ-Cl)]2. This iridium dimer 1 has a metastable structure with an asymmetric bridge, can spontaneously release metalloradicals and coordinatively unsaturated species in solution at room temperature, and exhibits high catalytic ability for synthetic applications.

Controlling Role of CaClOH in the Process of Dechlorination for Municipal Solid Incineration Fly Ash Utilization

The existence of high chlorine components in municipal solid waste incineration fly ash (IFA) has become a key bottleneck in the utilization of IFA as building materials. In this work, the chlorides in IFA were classified as alkali chlorine, calcium chloride, and calcium aluminum chloride, whereas CaClOH was the dominant phase of calcium chloride. For the first time, the effects of CaClOH on chlorine elimination for IFA-derived products by water-washing treatment or high-temperature treatment were carefully examined. The results indicated that IFA chlorine removal was closely linked to CaClOH phase dissolution, decomposition, volatilization, and transformation. CaClOH was easily removed by water washing and had excellent thermostability, even at 1300 °C. As shown in the results of XRD and XRF, the siliceous component would combine with CaClOH to volatilize as SiCl4, whereas the aluminous component would react with CaClOH to form chlorine-fixed and stable calcium aluminum chloride phases. The calcium aluminum chloride instead of CaClOH was in favor of the transformation of residual chlorine from soluble chlorine to chemically fixed chlorine. Therefore, the detoxification mechanism of chlorine for IFA could be summarized as washing dechlorination, volatilization dechlorination, and chemical fixation. As an application, the synergistic treatment of IFA with siliceous/aluminous materials could greatly reduce risks from soluble chlorine, while IFA-derived products were used as building materials.

Green-Light-Driven Reductive Elimination of Chlorine from a Carbene-Xanthylium Gold(III) Complex.

With the discovery of late transition metal platforms that support clean photoreductive halogen eliminations, we now describe an indazol-3-ylidene gold trichloride complex ([7]+ ) decorated at the 4-position by a xanthylium unit. This orange complex features a low energy band in the visible part of the spectrum, assigned to the charge transfer excitation of the indazol-3-ylidene/xanthylium donor/acceptor dyad. Green-light irradiation of this complex in the presence of a chlorine trap elicits the clean photoelimination of chlorine radicals, producing the corresponding gold(I) complex. This visible-light-induced photoreduction is very efficient, reaching quantum yields close to 10 %. A neutral analog of [7]+ featuring an anthryl group rather than a xanthylium unit proved to be perfectly photostable, supporting the importance of the xanthylium-based photoredox unit present in [7]+ .

Green‐Light‐Driven Reductive Elimination of Chlorine from a Carbene‐Xanthylium Gold(III) Complex

AbstractWith the discovery of late transition metal platforms that support clean photoreductive halogen eliminations, we now describe an indazol‐3‐ylidene gold trichloride complex ([7]+) decorated at the 4‐position by a xanthylium unit. This orange complex features a low energy band in the visible part of the spectrum, assigned to the charge transfer excitation of the indazol‐3‐ylidene/xanthylium donor/acceptor dyad. Green‐light irradiation of this complex in the presence of a chlorine trap elicits the clean photoelimination of chlorine radicals, producing the corresponding gold(I) complex. This visible‐light‐induced photoreduction is very efficient, reaching quantum yields close to 10 %. A neutral analog of [7]+ featuring an anthryl group rather than a xanthylium unit proved to be perfectly photostable, supporting the importance of the xanthylium‐based photoredox unit present in [7]+.

Photodriven Elimination of Chlorine From Germanium and Platinum in a Dinuclear PtII→GeIV Complex

AbstractSearching for a connection between the two‐electron redox behavior of Group‐14 elements and their possible use as platforms for the photoreductive elimination of chlorine, we have studied the photochemistry of [(o‐(Ph2P)C6H4)2GeIVCl2]PtIICl2 and [(o‐(Ph2P)C6H4)2ClGeIII]PtIIICl3, two newly isolated isomeric complexes. These studies show that, in the presence of a chlorine trap, both isomers convert cleanly into the platinum germyl complex [(o‐(Ph2P)C6H4)2ClGeIII]PtICl with quantum yields of 1.7 % and 3.2 % for the GeIV–PtII and GeIII–PtIII isomers, respectively. Conversion of the GeIV–PtII isomer into the platinum germyl complex is a rare example of a light‐induced transition‐metal/main‐group‐element bond‐forming process. Finally, transient‐absorption‐spectroscopy studies carried out on the GeIII–PtIII isomer point to a ligand arene–Cl. charge‐transfer complex as an intermediate.

Photodriven Elimination of Chlorine From Germanium and Platinum in a Dinuclear PtII →GeIV Complex.

Searching for a connection between the two-electron redox behavior of Group-14 elements and their possible use as platforms for the photoreductive elimination of chlorine, we have studied the photochemistry of [(o-(Ph2 P)C6 H4 )2 GeIV Cl2 ]PtII Cl2 and [(o-(Ph2 P)C6 H4 )2 ClGeIII ]PtIII Cl3 , two newly isolated isomeric complexes. These studies show that, in the presence of a chlorine trap, both isomers convert cleanly into the platinum germyl complex [(o-(Ph2 P)C6 H4 )2 ClGeIII ]PtI Cl with quantum yields of 1.7 % and 3.2 % for the GeIV -PtII and GeIII -PtIII isomers, respectively. Conversion of the GeIV -PtII isomer into the platinum germyl complex is a rare example of a light-induced transition-metal/main-group-element bond-forming process. Finally, transient-absorption-spectroscopy studies carried out on the GeIII -PtIII isomer point to a ligand arene-Cl. charge-transfer complex as an intermediate.

An insight to sequential ozone‑chlorine process for synergistic disinfection on reclaimed water: Experimental and modelling studies

Water reclamation plants (WRPs) are facing the challenges of ensuring microbial safety and require efficient disinfection systems. Sequential ozone‑chlorine disinfection is supposed to be a favorable alternative for reclaimed water disinfection. This study compared the inactivation efficiency of E.coli by single ozone, single chlorine, and sequential ozone‑chlorine disinfection approaches. Notably, a single ozone or chlorine process could only achieve a log removal rate of up to 5 log, whereas the sequential ozone‑chlorine disinfection could completely inactivate microorganisms (7.3 log). For sequential ozone‑chlorine disinfection, the efficiency of chlorination was improved by 2.4%–18.5%. The synergistic effect mainly attributed to the elimination of chlorine consuming substances by ozone. Through the chlorine decay model (CRS) fitting and calculating the integral CT value, the enhancement ability of ozone to chlorine disinfection was quantified. By introducing an enhancement coefficient (β), a succinct and accurate model was established to estimate the inactivation rate of sequential ozone‑chlorine disinfection (mean absolute percentage error: 0.035). The results and methodology of this study are informative to optimize the disinfection units of WRPs.

Hexachloroethane dechlorination in sulfide-containing aqueous solutions catalyzed by nitrogen-doped carbon materials.

This study demonstrated that nitrogen-doped carbon materials (NCMs) could effectively catalyze the chlorine elimination process in hexachloroethane (HCA) declorination in sulfide-containing environments for the first time. The kobs values of HCA dechlorination by sulfide in the presence of 10mg/L NCMs were higher than that of no mediator at pH 7.3 by one or two orders of magnitude. The catalytic capabilities of NCMs on HCA dechlorination were evident in common ranges of natural pH (5.3-8.9) and it could be accelerated by the increase of pH but be suppressed by the presence of dissolved humic acid. Moreover, NCMs exhibited much better catalytic capability on HCA dechlorination compared to the carbon materials, mainly owing to the combined contributions of pyridine N, including enhanced nucleophilic attack to HCA molecule by generating newborn C-S-S and activation of HCA molecule by elongating C-Cl bonds. The functions of pyridine N in micron-sized NCMs with mesopores were better than in nano-sized NCMs on HCA dechlorination. These findings displayed the potential of NCMs, when released into sulfide-containing environments, may significantly increase the dechlorination of chlorinated aliphatic hydrocarbons.

Renal lithiasis in pediatric patients: correlation of methods that depend on 24-h collections with simpler methods that do not require timed urine

IntroductionDaily practice requires quick, simple and accessible methods to appropriately assess the urinary excretion of solutes in diagnostic or follow-up evaluations of children with renal lithiasis. ObjectivesThe objective of this study was to correlate urine elimination of substances related to renal lithiasis that depend on the volume of excreted urine in a unit of time with other parameters that are calculated by measuring the concentration of these substances in blood and urine, such as urinary ratios, fractional excretions and excretion rates. Materials and methodsThe study included 401 healthy children aged 3–14 years (187 boys and 214 girls), mean age 8,78 ± 3,40 years. The analysis was carried out by Pearson’s correlation coefficient. ResultsThere was significant correlation between the elimination of sodium, potassium and chlorine in 24-h urine sample and the urinary ratios and fractional excretions of these ions.Urinary ratios and rates of excretion of calcium, uric acid, phosphate, magnesium, citrate and oxalate were highly correlated with the determinations of these substances in 24-h collections. ConclusionsThese equations provide relevant information for the study of the etiology of renal lithiasis in children, as well as about compliance to dietary treatment. They also assess the effectiveness of the various treatments used in these patients, without having to resort to 24-h collections, which pose a considerable challenge in the pediatric age group.

Photoreductive chlorine elimination from a Ni(iii)Cl2 complex supported by a tetradentate pyridinophane ligand.

Herein we report the isolation, characterization, and photoreactivity of a stable NiIII dichloride complex supported by a tetradentate pyridinophane N-donor ligand. Upon irradiation, this complex undergoes an efficient photoreductive chlorine elimination reaction, both in solution and the solid-state. Subsequently, the NiIIICl2 species can be regenerated via a reaction with PhICl2.

Single-Mode W-Type Optical Fiber Stable Against Bending and Radiation

It is shown that single-mode fluorosilicate optical fibers fabricated with the aid of modified chemical vapor deposition exhibit a significant decrease in the radiation resistance when 1 mol % GeO2 is introduced into the silica-glass core. Elimination of chlorine and OH group impurities in the silica glass of the core of the fluorosilicate single-mode fiber leads to a relatively low level of radiation-induced attenuation. Prior to radiation processing, the loss factors of optical fiber are 0.18 and 0.3 dB/km at wavelengths of 1.55 and 1.31 μm, respectively. The dependence of optical loss of such fibers on the bend diameter ranging from 6 to 12 mm is studied.

Litiasis en pediatría: correlación de métodos que dependen de la recogida de orina de 24 horas con otros más sencillos que no requieren orina minutada

IntroductionDaily practice requires quick, simple and accessible methods to appropriately assess the urinary excretion of solutes in diagnostic or follow-up evaluations of children with renal lithiasis. ObjectivesThe objective of this study was to correlate urine elimination of substances related to renal lithiasis that depend on the volume of excreted urine in a unit of time with other parameters that are calculated by measuring the concentration of these substances in blood and urine, such as urinary ratios, fractional excretions and excretion rates. Materials and methodsThe study included 401 healthy children aged 3-14 years (187 boys and 214 girls), mean age 8.78±3.40 years. The analysis was carried out by Pearson's correlation coefficient. ResultsThere was significant correlation between the elimination of sodium, potassium and chlorine in 24-hour urine sample and the urinary ratios and fractional excretions of these ions.Urinary ratios and rates of excretion of calcium, uric acid, phosphate, magnesium, citrate and oxalate were highly correlated with the determinations of these substances in 24-hour collections. ConclusionsThese equations provide relevant information for the study of the etiology of renal lithiasis in children, as well as about compliance to dietary treatment. They also assess the effectiveness of the various treatments used in these patients, without having to resort to 24-hour collections, which pose a considerable challenge in the pediatric age group.

Torrefaction as a Pretreatment Technology for Chlorine Elimination from Biomass: A Case Study Using Eucalyptus globulus Labill

The recognition of the effects of fossil fuel consumption resulted in several agreements, legislation, and projects focusing on the minimization of impacts caused. Biomass is a versatile energy source. Eucalyptus is a fast-growing crop, mainly used by the pulp and paper industry. Torrefaction is a thermochemical conversion process that can improve biomass fuel properties, enabling its use in the energy sector. However, correct management of biomass is crucial for the sustainability of this process. Torrefaction can also be used to eliminate some elements that can hinder subsequent conversion processes. One example is chlorine, which, during combustion or gasification processes, can form hydrochloric acid that leads to corrosion of metal surfaces. In this context, this research aimed to determine the temperature at which chlorine is eliminated during torrefaction process. For this purpose, several tests were performed at different temperatures and residence times. All samples were analyzed before and after the process, and were characterized by proximate and elemental analysis, calorimetry, and chlorine titration. The analysis showed that, even for the lowest torrefaction temperature used, chlorine content was already below the detection value, showing that, even at lower temperatures, thermal treatment is an efficient technique for the elimination of chlorine from biomass.

Landfill leachate treatment using activated carbon obtained from coffee waste

ABSTRACT A set of experiments were carried out in order to establish and evaluate the potential of activated carbon, produced from coffee waste in adsorption process, in the depuration of landfill leachate. Different reagents were studied in the activation of carbon: HCl, HCl + H2O2, H3PO4, H3PO4 + H2O2, all with an impregnation rate of 1:1. The activated carbon that showed the best global results was activated with H3PO4, obtaining a 51.0, 32.8, 66.0, 81.0 and 97.1% elimination of chemical oxygen demand, ammonia, total chlorine, bromine and copper, respectively. This activated carbon has a total pore area of 4.85 m2/g and a median pore diameter of 65.32 micrometers. When different loads of this carbon were placed in a stirrer system in contact with landfill leachate, with the aim of evaluating the effect of the adsorption load and contact time, the concentration of ammonia decreased from the beginning of the adsorption process to the end of it, and the removal of ammonia increased with the increase in the adsorbent load. However, the trend of the amount adsorbed per unit mass decreased with increased dosage. The model Freundlich equilibrium isotherm fits experimental data adequately, giving R2 values of 0.95, 1/n of 0.5183, and a K value of 7.08*10-5 L/g, being favourable for adsorption process.

Effect of chlorine elimination from Pt-Sn catalyst on the behavior of hydrocarbon reconstruction in propane dehydrogenation

The effect of chlorine elimination from Pt-Sn catalyst on the behavior of hydrocarbon reconstruction in propane dehydrogenation was investigated. The results showed that the chlorine elimination significantly affects multiple characteristics of the catalysts, the type of Pt active phases, and the behavior of hydrocarbon reconstruction. There was no apparent change in catalyst structure. In contrast, the acidity of the catalyst, its specific surface area, and pore volume remarkably decreased whereas its mean pore diameter increased under the same conditions. The degree of Pt sintering, which is disadvantageous to the reaction, was also aggravated. The chlorine elimination also influenced the behavior of hydrocarbon reconstruction in propane dehydrogenation and demonstrated a crucial function in determining selectivity as evidenced by coking experiments. In this work, a strong correlation was established to demonstrate the relation between the structure of Pt active phase and the behavior of hydrocarbon reconstruction in propane dehydrogenation. It is an optimum progress that the chlorine elimination conditions of the Pt active phases centered on the Pt(100) surfaces and the PtSnK/Al2O3 exhibited the best catalytic performance and a low coking rate. Finally, a new model was established to describe the influence of chlorine elimination on the interactions between Pt and SnOx.

Correction to "Photoreductive Elimination of Chlorine from Antimony in an [SbPd]VII Complex".

Correction to "Photoreductive Elimination of Chlorine from Antimony in an [SbPd]VII Complex".

Photoreductive Elimination of Chlorine from Antimony in an [SbPd]VII Complex.

As part of our ongoing interest in main group species that support the photoreductive elimination of halogens, we have synthesized [Cl3SbVPdIICl2(o-dppp)2] (o-dppp = o-(Ph2P)C6H4), a palladium dichloride complex featuring a Lewis acidic trichlorostiborane moiety positioned within the ligand architecture. Upon UV irradiation, this complex undergoes a clean photoreductive chlorine elimination reaction which produces [Cl2SbIVPdICl(o-dppp)2], a complex with a covalent Sb-Pd bond. This transformation illustrates the viability of antimony as an element from which a halogen can be photoeliminated; it also shows that a metal halide can be photolytically coupled with a main group halide to generate a metal-element bond.