Chloride Sulfate Research Articles

Chloride effect on sulfate attack in hydrated Portland-limestone cement assessed by 29Si NMR spectroscopy and thermal analysis

Structural alterations in the C-S-H phase of hydrated Portland-limestone cements, caused by magnesium sulfate attack, were quantitatively assessed using 29Si MAS NMR spectroscopy, considering the presence of sodium chloride in the corrosive medium and the limestone content in cement. Quantitative information about crystalline deterioration products (ettringite, thaumasite, gypsum, brucite) was retrieved from thermogravimetric analysis. Scanning electron microscopy combined with elemental analysis indicated their accumulation areas. Formation of cross-linked silicate chains and reduction of bridging/pairing SiO4 tetrahedra in C-S-H was noted. The presence of chlorides decreased cross-linking of SiO4 tetrahedra and reduced gypsum formation and Ca depletion from the matrix. Precipitation of brucite at the edge of the specimens possibly inhibited the promotion of the attack process. Chlorides penetrated deeper into the matrix compared to sulfates. Increasing limestone content in cement led to a higher mean chain length of cross-linked chains and AlO4/SiO4 ratio in the sulfate-bearing environment. The extent of C-S-H degradation in the cement pastes with the highest limestone content was independent of the exposure conditions. Cement with approx. 12% limestone content can be considered of equal performance to ordinary Portland cement in severe sulfate–chloride solutions.

Biogeochemical State of Salinized Irrigated Soils of Central Fergana (Uzbekistan, Central Asia)

The Central Fergana region is one of the overpopulated regions of Central Asia, which includes parts of Uzbekistan, Kyrgyzstan, and Tajikistan. Here, in the dry subtropical climate are the most ancient, irrigated oases used for agriculture. Fergana valley is the key to the food security of the region as a whole. The article provides information on diversity and chemical composition of newly developed, new and old-irrigated Calcisols soils formed on alluvial and alluvial–prolluvial sediments. Soils are poor with organic matter (0.37–0.81% of organic carbon), with high nitrogen content (C/N ratio is 4.92–5.79), and with neutral (7.01–7.30) pH values. Data on the content and the ratio of the key components of soil salinity (Na2CO3, Ca(HCO3)2, CaSO4, MgSO4, Na2SO4, NaCl) and the bulk content of salts in soils under different irrigation regimes are presented. It was shown that Na2CO3 concentration is minimal in all the soils, and this salt presents only in ground waters (0.100–0.135 g L−1). Newly irrigated soils are characterized by higher content of salts than old irrigated soils. All the soils investigated are characterized by increasing salinity rate within the soil depth with the highest content of all salts in ground waters. This chloride–sulfate type of salinization is most pronounced in all the soils studied. Gypsum content in agricultural soils results in limited water and nutrient retention and the potential for dissolution, primarily in response to irrigation. The soils of the Fergana Valley are also subjected to polychemical pollution, so the content of trace elements in them was studied. Irrigated meadow-takyr and meadow-saz soils show low levels of environmental hazard, but irrigation results in accumulation of such trace elements as nickel (30 mg kg−1), arsenic (11.75 mg kg−1), bromine (5.00 mg kg−1), antimony (1.48 mg kg−1), cesium (5.00 mg kg−1), and hafnium (2.97 mg kg−1). Irrigation also affects the soil texture and thus increases fine particle percentages in the superficial soil horizons. Thus, the complex chemical characteristics of salinized soils are presented for numerous irrigated landscapes of the region.

Thermal atomic layer etching of cobalt using sulfuryl chloride for chlorination and tetramethylethylenediamine or trimethylphosphine for ligand addition

Thermal atomic layer etching (ALE) of cobalt was developed using sulfuryl chloride (SO2Cl2) for chlorination and either tetramethylethylenediamine (TMEDA) or trimethylphosphine (PMe3) for ligand addition. In situ quartz crystal microbalance (QCM) measurements were used to monitor the thermal ALE of cobalt using the SO2Cl2/TMEDA and SO2Cl2/PMe3 processes. For every SO2Cl2 exposure, there was a mass gain during chlorination. For every TMEDA or PMe3 exposure, there was a mass loss during ligand addition. The result was a net removal of cobalt during each chlorination/ligand-addition reaction cycle. Average etch rates determined from QCM measurements for the SO2Cl2/TMEDA process at 175, 200, 225, 250, 275, and 300 °C were 0.62 ± 0.41, 1.35 ± 0.64, 2.31 ± 0.91, 6.43 ± 1.31, 10.56 ± 2.94, and 7.62 ± 4.87 Å/cycle, respectively. These etch rates were corroborated using x-ray reflectivity (XRR) studies on cobalt thin films on silicon coupons. Quadrupole mass spectroscopy analysis also revealed that the cobalt etch product from TMEDA exposures on CoCl2 powder was CoCl2(TMEDA). The SO2Cl2/TMEDA process could remove the surface chloride layer formed by each SO2Cl2 exposure with one TMEDA exposure. In contrast, the SO2Cl2/PMe3 process required 20–40 individual PMe3 exposures to remove the surface chloride layer formed from each SO2Cl2 exposure at 130–200 °C. An increasing number of PMe3 exposures were needed as the temperature decreased below 130 °C. The etch rates for the SO2Cl2/PMe3 process with multiple PMe3 exposures were 2–4 Å/cycle as determined by the QCM and XRR studies. For both the SO2Cl2/TMEDA and SO2Cl2/PMe3 processes, the etch rate was determined by the amount of CoCl2 created during the SO2Cl2 exposure. Thicker surface CoCl2 layers from larger SO2Cl2 exposures resulted in higher Co etch rates that could exceed one crystalline unit cell length. Atomic force microscopy measurements determined that the cobalt surface roughness decreased after Co ALE with the SO2Cl2/TMEDA process. In contrast, the cobalt surface roughness increased after Co ALE with the SO2Cl2/PMe3 process. The chlorination and ligand-addition mechanism should be generally applicable for metal ALE for metals that form stable chlorides.

Perceptual Visual Inversion Secondary to Inhalation of Fumes of Sulfuryl Chloride (P4-12.003)

<h3>Objective:</h3> To describe a case of alteration of visual perception of objects and faces following Inhalation of Sulfuryl Chloride. <h3>Background:</h3> The neural pathways for object perception and recognition include two information-processing streams originating in occipital cortex. Dorsal stream extends to parietal lobe, and Ventral stream extends to inferior temporal lobe. Damage to each pathway can affect elements of visual perception affecting object recognition (what) and spatial perception (where and how). <h3>Design/Methods:</h3> Case report/literature review. <h3>Results:</h3> Fifty-three-year-old woman presented following inhalation of toxic fumes. Over the following hours and days, she lost the ability to speak her native tongue and could only communicate in her second language. She complained that most objects in her visual field were inverted, but not the whole scene. There are few reports of subjective visual field inversion without robust testing. We formulated novel experiments to probe deficits unique to her. On shape from shading (eggs vs. cavities) test, the light on top looked like cavities, unlike neurotypicals - implying that for her, the sun shines from below. She recognized upside-down faces faster than the correct way up and could easily read upside down. Prosopagnosics identify inverted faces more accurately than neurotypicals. We suggest there is a selective injury to the ventral stream,” What Pathway,” in the inferior temporal lobe (associated with object recognition). The insult relatively spared the dorsal stream “How and Where” in the posterior parietal cortex. This may explain why she exhibited mild Balint syndrome (optic ataxia, simultagnosia, oculomotor apraxia). Alternatively, the initial Balint may have been progressively corrected via visual feedback during reaching. Such correction does not occur for the ventral stream because we do not usually palpate people’s faces. <h3>Conclusions:</h3> Inversion of vision is rare but using stimuli designed to probe specific symptoms, we gain insight into cascade of neural signals that culminate in perception. <b>Disclosure:</b> Dr. Ramachandran has nothing to disclose. Dr. Kakawand has nothing to disclose. Dr. McGeoch has nothing to disclose. Mr. Ahern has nothing to disclose. Dr. Tobias has nothing to disclose.

Comparative Experiments on the Role of CO2 in the Gold Distribution between Pyrite and a High-Salinity Fluid

Experimental studies were conducted to identify the physical and chemical features of gold’s behaviour in hydrothermal processes linked to ore formation and involving CO2 in oxidized deposits. With the aid of the autoclave method, in a temperature range of between 200 and 400 °C, the isochoric dependences of the PVT parameters of concentrated sulphate chloride fluids were plotted, both in the presence and absence of CO2. Our experiments established that concentrated sulphate–chloride fluids (22 wt % Na2SO4 + 2.2 wt % NaCl) that lack CO2 are characterized by a wide supercritical temperature range, with homogenization temperatures of between 250 and 325 °C. In the presence of CO2, the same type of fluids showed heterogenization at a molar fraction of XCO2 = 0.18 (t = 192 °C, P = 176 bar). The process of homogenization for these low-density and high-salinity fluids was impossible at temperatures between 375 and 400 °C and at pressures between 600 and 700 bar. The behaviour of gold was studied during its interaction with a basic composition fluid of sulphate–chloride. We applied the autoclave method under the conditions of a simultaneous synthesis of pyrite and gold dissolution (metallic Au), at a temperature of 340 °C and at a pressure of 440 bar. High Au concentrations (up to 4410 ppm of Au in CO2-bearing fluids) were attained at high gold solubilities (up to 13.5 ppm in the presence of CO2), owing to the process of Au reprecipitation within the pyrite phase. We did not detect Au in the pyrite when we used the XRD or SEM methods, which suggested that it might be present as invisible gold. High values of the distribution coefficient (KD = CAu(solid)/CAu(solution)) in the fluids lacking (KD = 62) and bearing CO2 (KD = 327) empirically confirmed the possibility that gold concentrates in pyrite in structurally non-binding forms.

CATALYSIS BY PHOSPHORUS AND SILICON COMPOUNDS IN THE SYNTHESIS OF OXYNAPHTOIC ACID ANILIDES

Catalysis of the acylation of aniline with 3-­hydroxy-2-naphthoic, 1-hydroxy-2-naphthoic, 2-hydroxy-1-naphthoic and 1-hydroxy-4-naphthoic acids by phosphorus P(III) and silicon Si(IV) compounds leads to the formation anilides of the corresponding hydroxy­naphthoic acids under mild conditions (ortho-xylene, 146.5–147 °C) in almost quantitative yield.&#x0D; Among P(III) phosphorus trichloride and tribromide; phosphorous, 1-hydroxyethyli­de­ne-di­phos­phonic, pyrophosphorous and me­ta­phos­phorous acids; trimethyl-, dimethyl- and diethylphosphites; phosph(III)azan proved to be active catalysts; among Si(IV) – tri­chloro-(methyl)silane, dichloro(ethyl)silane, dichloro­(dimethyl)silane, tetrachlorosilane and tet­ra­ethoxysilane are active.&#x0D; The catalysts were used in an amount of only 2% mole. from hydroxynaphthoic acid, which is 15–35 times less than the conventional use of the same compounds as condensing agents in the synthesis of carboxylic acid arylamides. P(V) compounds, thionyl chloride, and sulfuryl chloride practically do not exhibit catalytic activity. The presence of catalytic activity only in P(III) compounds, capable of forming phosphorous acid in the reaction mass, does not contradict to the previously proposed mechanism of P = O-nucleophilic catalysis for the reaction of substituted benzoic acids with aniline catalyzed by PCl3.&#x0D; In general, the use of P(III) and Si(IV) compounds as catalysts in the preparation of hydroxybenzoic and hydroxynaphthoic acid anilides successfully complements the range of catalysts, based on Ti(IV) compounds, previously used in the formation of substituted benzoic and naphthoic acid anilides (containing no aromatically bonded hydroxy group), allowing to create a universal method for their synthesis.

A novel protocol to recycle zirconium from zirconium alloy cladding from used nuclear fuel rods

A potential new zirconium recycling protocol has been demonstrated using unirradiated Zircaloy-based claddings and depleted uranium oxide for the chemical removal of zirconium alloy cladding in used nuclear fuel (UNF) rods from light water reactors. This protocol is based on the application of three new scientific findings. First, a new lower temperature chlorination reaction of zirconium with sulfur monochloride is described. Second, the high solubility of zirconium chloride in thionyl chloride is used to separate it from uranium oxide fuel and fission and activation contaminants. Finally, in the third step, the zirconium chloride is purified by simple recrystallization from thionyl chloride. Utilizing sulfur chloride solvents for a lower temperature liquid-based chemical digestion and purification of zirconium alloy claddings reduces technical complications experienced by current high temperature gas phase chlorination strategies, such as contamination of product streams. This novel protocol has been demonstrated on a 3–50 g scale of unirradiated zirconium alloy, with no significant change in the time required for complete chlorination (3–4 h). This zirconium chlorination protocol has also been performed in the presence of depleted uranium oxide pellets. The depleted fuel pellets do not affect zirconium chlorination, and the chlorination protocol does not chemically or physically alter the fuel pellets. A preliminary description of an industrial protocol to recycle nuclear grade zirconium from UNF rods is presented.

Consideration on Use of the Corn Plant Ash-Based Concrete related to the Salt and Acid Attack: A Review

Many concrete buildings are found around the seashore, such as bridges, ports, piers, jetty, break water, etc. During the service life, contact between concrete and seawater cannot be avoided. The seawater can cause damage to concrete. This condition can affect the durability of concrete, which in turn will reduce the mechanical properties and structural performance of concrete. In addition, rainwater can be acidic, which caused of large number of industries or factories in Indonesia, motor vehicle emissions, forest fires, volcanic eruptions, etc. Some of chemicals contained in acid rain include sulfuric acid (H 2 SO 4), nitric acid (HNO 3), and chloride acid (HCl). Acid solution also can give rise to deterioration to the concrete constructions. It is necessary to develop a concrete technology that can inhibit or resist the attack of these salts and acids. But the adding cement is not the solution. Currently, many researches are being carried out on how waste or garbage can be utilized as a cementitious material, which is expected able to improve the quality of concrete, and be environmentally friendly. In this research, the corn plant waste is considered as the material to be investigated that related to the concrete durability due to the salt and acid attack.

Nitrate–nitrite–nitric oxidation of porphyry copper ore with subsequent activated sulfuric acid-and chloride leaching of copper and noble metals

Nitrate–nitrite–nitric oxidation of porphyry copper ore with subsequent activated sulfuric acid-and chloride leaching of copper and noble metals

Copper-promoted indirect trifluoromethylthiolation of sulfuryl chloride with TMSCF3: facile access to trifluoromethyl thioethers

Trifluoromethyl thioether compounds were synthesized by a simple, mild and efficient method.

The deterioration mechanisms of hardened cement paste exposed to combined action of cyclic wetting–drying, salt attack and carbonation

In saline soil or salt lake regions, cement-based materials suffer from combined action of salt attack (SA), carbonation, and cyclic wetting–drying (CWD), and its deterioration mechanism remains an open question. Taking advantage of multiple techniques, this study is dedicated to unveiling the deterioration mechanism of hardened cement paste (HCP) exposed to combined action of SA (sulfate salt or sulfate–chloride salt), carbonation (natural carbonation, 0.035 vol.% CO2 or accelerated carbonation, 20 vol.% CO2) and CWD. The results show that, when exposed to combined action of SA, carbonation and CWD, HCP exhibits distinct deterioration mechanisms depending on the concentration of carbon dioxide: chemical sulfate attack (i.e., formation of ettringite and gypsum) is mainly responsible for the deterioration of HCP in the case of natural carbonation, whereas decomposition of C-S-H and formation of gypsum are both responsible for the deterioration of HCP in the case of accelerated carbonation. The presence of sodium chloride in sulfate–chloride solution inhibits the sulfate attack as well as carbonation attack of HCP.

Radiolytic evaluation of select sulfur chlorides (S2Cl2 and SOCl2) for advanced low temperature chlorination of zirconium-based used nuclear fuel cladding

New sulfur chloride compounds—sulfur monochloride (S2Cl2) and thionyl chloride (SOCl2)—have been proposed as alternative chlorinating agents for the chemical decladding of zirconium-based used nuclear fuel cladding materials. However, the radiation stability of these compounds has not been thoroughly evaluated, despite envisioned process conditions involving intense, multi-component radiation fields. Knowledge of the radiation chemistry of these sulfur chlorides is essential for the development and optimization of alternative chlorination technologies. To this end, we present preliminary findings on the gamma radiolysis of neat S2Cl2 and SOCl2 at ambient temperature up to ∼ 34 MGy. In this study, Raman spectroscopy and density functional theory calculations were used to identify the Raman-active degradation products from S2Cl2 and SOCl2 radiolysis. Both sulfur chloride compounds exhibited significant radiation resistance, with respect to changes in the Raman signatures of the parent compounds and the ingrowth of Raman-active degradation products. For S2Cl2, molecular chlorine (Cl2) was directly identified as the predominant degradation product, which was completely consumed at higher absorbed doses (> 9 MGy). Similarly, the main degradation product from SOCl2 radiolysis was also Cl2, although in this system it continued to grow in with dose over the entire dose range. An “SO” containing degradation product(s) was also identified as a compliment to Cl2. Overall, the perceived radiation resistance of these sulfur chloride compounds makes them suitable for inclusion in a used nuclear fuel chemical decladding process, especially as radiolytically formed Cl2 can be used to reform the parent compounds, thereby increasing the longevity of the solvents used.

Cl- and Al-Doped Argyrodite Solid Electrolyte Li6PS5Cl for All-Solid-State Lithium Batteries with Improved Ionic Conductivity.

Argyrodite solid electrolytes such as lithium phosphorus sulfur chloride (Li6PS5Cl) have recently attracted great attention due to their excellent lithium-ion transport properties, which are applicable to all-solid-state lithium batteries. In this study, we report the improved ionic conductivity of an argyrodite solid electrolyte, Li6PS5Cl, in all-solid-state lithium batteries via the co-doping of chlorine (Cl) and aluminum (Al) elements. Electrochemical analysis was conducted on the doped argyrodite structure of Li6PS5Cl, which revealed that the substitution of cations and anions greatly improved the ionic conductivity of solid electrolytes. The ionic conductivity of the Cl- and Al-doped Li6PS5Cl (Li5.4Al0.1PS4.7Cl1.3) electrolyte was 7.29 × 10-3 S cm-1 at room temperature, which is 4.7 times higher than that of Li6PS5Cl. The Arrhenius plot of the Li5.4Al0.1PS4.7Cl1.3 electrolyte further elucidated its low activation energy at 0.09 eV.

Effects of torrefaction on ash-related issues during biomass combustion and co-combustion with coal. Part 1: Elemental partitioning and particulate matter emission

Torrefaction is a promising technology to scale up the utilization of biomass for power purposes. The ash-related issues during biomass combustion and co-combustion are essential to be addressed, however, on which the effects of torrefaction are seldom concerned and need in-depth and comprehensive investigation. To provide useful information related, the authors conducted a series of studies. In the present work, the particulate matter (PM) emission during combustion is focused on. Three biomasses were torrefied at a fixed-bed reactor, and the elemental release and transformation during torrefaction were characterized through chemical fractionation analysis. The combustion tests of the raw and torrefied biomass and their blends with two typical coals were conducted on a drop-tube furnace at 1300℃ in air. The PM10 (particulate matter with an aerodynamic particle size below 10 μm) collected by a Dekati low-pressure impactor and PM10+ (particulate matter with an aerodynamic particle size above 10 μm) collected by a Dekati cyclone were characterized by a scanning electron microscope equipped with energy dispersive spectrometer (SEM-EDS). The results indicate that torrefaction effectively reduces S and Cl in biomass while slightly reducing the alkalis. The contents of refractory elements (Mg, Ca, and Fe) are hardly influenced. Torrefaction promotes the transformation of AAEMs (alkaline and alkaline earth metals) into less-reactive forms (HCl-soluble and insoluble). The vaporization of alkalis, S, and Cl during biomass combustion is reduced and the retention of AAEMs into aluminosilicates is promoted after torrefaction. This reduces the emission of PM1 (particulate matter with an aerodynamic particle size below 1 μm) from biomass combustion. During co-combustion, the PM emission largely depends on the combined effects of elemental vaporization, competing reactions (alkalis against Mg, Ca, and Fe), retention of metals into aluminosilicates, and sulfation of chlorides. The inhibited effect of torrefaction on mineral vaporization reduces the formation of PM1 by condensation. The emission of PM1-10 (particulate matter with an aerodynamic particle size between 1 and 10 μm) either increases due to the promoted retention of the metals in coarse particles or decreases by agglomerating into PM10+. Torrefaction shows a preferable performance concerning its effects on PM emission during biomass combustion and co-combustion with coal.

Influence of Chlorinating Agents on the Formation of Stable Biomarkers in Hair for the Retrospective Verification of Exposure.

Chlorine, as a dual-use chemical, is an essential industrial chemical which has been used as a chemical weapon in the past due to its toxicity and availability. The retrospective verification of chlorine intoxication is often especially challenging, and unambiguous markers are still missing. In this study, the effects of different chlorinating and oxidizing agents on human hair were investigated. Samples were exposed to a variety of chlorinating chemicals for a short time and then completely hydrolyzed by a HBr solution to break down their keratin proteins into individual amino acids. After derivatization and targeted liquid chromatography-mass spectrometry analysis, 3-chlorotyrosine and 3,5-dichlorotyrosine were unambiguously identified from human hair exposed to chlorine, hypochlorite, and sulfuryl chloride. Our results show long-term stability of these markers in the biological matrix, as the chlorotyrosines can still be found 10 months post-exposure at the same levels. Finally, an untargeted analysis was able to discriminate between some of the different intoxicants.

High-efficiency leaching of Al and Fe from fly ash for preparation of polymeric aluminum ferric chloride sulfate coagulant for wastewater treatment

Preparation of inorganic polymer coagulants from circulating fluidized bed (CFB) fly ash is one of the most significant value-added and environment-friendly approaches. Nevertheless, CFB fly ash presents relatively low solubility in acidic systems, which limits its utilization efficiency. In this paper, enhanced metal leaching from CFB fly ash using combined HCl-H2SO4 leaching process for polymeric aluminum ferric chloride sulfate (PAFCS) preparation was proposed. PAFCS with the different molar ratios of Al3+/SO42− and Al3+/Fe3+ were prepared from as-obtained leaching liquors and characterized by SEM, XRD, FTIR, and coagulation experiments. The leaching efficiencies of Al and Fe in CFB fly ash were up to 96.75% and 97.64% by combined HCl-H2SO4 leaching process. The optimal molar ratios of Al3+/SO42− and Al3+/Fe3+ for the turbidity and UV254 removal were 10:1 and 10:1, respectively, due to the three-dimensional chain-net structure and the highest [Al + Fe]b content. When applied to biochemical effluent of coking wastewater treatment, PAFCS exhibited excellent removal performance on both humic acid-like and fulvic acid-like matters. The resultant flocs of PAFCS presented the largest recovery factor (Rf = 0.37) and strength factor (Sf = 0.79) in contrast with PAC and PAFC. This work provides a novel and high-efficient Al and Fe leaching strategy from CFB fly ash to prepare Al-Fe coagulant.

Experimental investigation on the behaviour of crumb rubber concrete columns exposed to chloride–sulphate attack

This research presents an experimental study to investigate the structural behaviour of crumb rubber concrete (CRC) short columns subjected to different exposure conditions. Thus, three different concrete mixtures were designed with varying replacement ratios of crumb rubber (CR) (0 %, 10 %, and 20 %) to the total volume of fine aggregate. The experimental program of this study includes the testing of 27 short columns characterised by three different environmental conditions, that is, laboratory, chloride, and sulphate. Nine columns were kept in a neutral laboratory environment condition. Nine columns were immersed in a sodium chloride solution, and the remaining nine columns were immersed in a magnesium sulphate solution for 90, 180 or 365 days. Experimental results illustrate that the addition of CR to concrete adversely affects the mechanical properties and durability of the CRC. The column strength, stiffness, and toughness continuously degrade with the increase in the CR content and immersion time. The column’s strength, stiffness, and toughness decrease as the level of corrosion damage increases. Specifically, the reduction levels in the strength of the columns immersed in 10 % magnesium sulphate solution are more noticeable than those immersed in 10 % sodium chloride solution.

A simple one-pot oxidation protocol for the synthesis of dehydrohedione from Hedione

A new method for the oxidation of Hedione 1 to dehydrohedione 2, a high value intermediate in the flavour and fragrance industry, has developed based upon one pot α-chlorination-elimination sequence which can be readily scaled. The spontaneous elimination of the α-chloro in methanol was unprecedented and has allowed for the oxidation, typically performed in multiple steps/reactions, to be carried out as a one-pot protocol. A continuous flow process for performing the reaction utilising sulfuryl chloride has also demonstrated allowing for steady, safe evolution of SO2 gas during the reaction.

Catalyst-Tuned Electrophilic Chlorination of Diverse Aromatic Compounds with Sulfuryl Chloride and Regioselective Chlorination of Phenols with Organocatalysts.

In this work, we demonstrate that diverse aromatic compounds can be selectively chlorinated through the fine-tuning of the reactivity of sulfuryl chloride (SO2Cl2) by organocatalysts. Acetonitrile has been identified to activate SO2Cl2 most strongly, thus enabling even chlorination of p-xylene with high yields. 1,4-Dioxane effects chlorination of oxidation-labile aromatic compounds such as p-cresol and 2-naphthol with high yields, 95% and 85%, respectively. An array of potential catalysts has been screened for ortho- and para-selective chlorination of phenols. Thus, we found that acetonitrile, (S)-BINAPO (5 mol %), and diisopropyl ether (4.00 equiv) can catalyze the chlorination of phenols in a para-selective manner (with ≤4:96 o:p ratio), whereas Nagasawa's bis-thiourea (1 mol %), phenyl boronic acid (5 mol %), and (S)-diphenylprolinol (1 mol %) exhibit high ortho selectivity [with ≤99:1 o:p ratio by (S)-diphenylprolinol].

Citizen Science as a Co-Creative Measure to Water Quality: Chemical Data and Local Participation in a Rural Territory

It is becoming increasingly clear that the threat to the use of natural landscapes and persistent droughts are affecting the water quality of rural communities. The socio-ecological fit emerges as an aid to advance in the search for solutions to environmental problems in rural communities. Consequently, between May 2016 and September 2021, an interdisciplinary study of community-based water quality monitoring (CWQM) was implemented at a coastal catchment in the Ñuble region, Central Chile. The objective of the study was to involve the participation of local communities in initiatives to control the water quality of various parameters [pH, total iron (FeT), alkalinity as CaCO3, hardness (Ca2+ and Mg2+), sodium (Na+) and potassium (K+), water temperature, sulfate (SO42−) chloride (Cl−), and nitrate (NO3-)] in groundwater, share local knowledge, and apply co-creative measures for improving water conservation. In situ chemical data were also analyzed in the laboratory to check data quality. The PHREEQC hydrogeochemical model is used to characterize hydrogeochemical parameters of groundwater and to know about hydrogeochemical processes related to water quality. High levels of NO3− and FeT are recorded in 75% of the groundwater samples, mainly when water scarcity is higher during the summer. According to Chilean standards, nitrate levels exceed the maximum permissible limits for drinking water. A type of mainly Ca (Mg)–HCO3− carbonated water was recorded with Ca2+, Na+, Mg2+, and HCO3− as dominant ions. This study demonstrated the opportunity of a rural community group to help fill spatial data gaps in water quality monitoring and reassess water quality protection, especially considering the decrease in water availability in the region. Therefore, the community together with researchers can respond with an early alert system to water quality to collaborate with the implementation of rural drinking established on a community-based water quality monitoring. Moreover, to prioritize the level of urgency of rural water, minimize water pollution and improve the perception of the water and the resilience of their social–ecological system.