Potassium Ethyl Xanthate Research Articles

A novel method based on solid phase extraction and liquid chromatography-tandem mass spectrometry warrants occurrence of trace xanthates in water

Huge volumes of wastewater containing organic flotation reagents such as xanthates have been released into the environment via mining activities, greatly threatening the eco-environment safety. A simple and fast method is urgently needed for accurate analysis of various xanthates in mining and environmental water. Here, a robust method is realized for simultaneous determination of three trace xanthates (i.e., potassium ethyl xanthate, potassium butyl xanthate, and potassium isopropyl xanthate) in environmental water samples, including eutrophic water and flotation wastewater using solid phase extraction (SPE) and HPLC-MS/MS. HPLC-MS/MS parameters, SPE cartridges and eluting solvents, pH values, and SPE procedures were optimized. The new method had an excellent linearity in the range of 1–1000 μg/L (R2 ≥ 0.998), low limits of detection (0.02–0.68 μg/L), and satisfactory accuracy and precision (72.9%–107.6% of average recoveries and <5% of relative standard deviations at 1, 10, 50, and 500 μg/L of xanthates). This is a first method developed for determination of trace xanthates in water samples. It was successfully applied to determine the target analytes in outdated flotation wastewater and river water samples, warranting the occurrence of trace xanthates (0.13–16.9 μg/L) in water and necessity of systematic investigation on environmental fate and risk of xanthates.

Trifunctional mesoporous magnetic adsorbent-photocatalyst nanocomposite for efficient removal of potassium ethyl xanthate from mining wastewater

Xanthates are largely used in the mining industry as mineral flotation agents, causing serious environmental problems, and therefore, removing them effectively is a significant barrier for sustainable green mining that needs to be addressed. Here, nanostructured mesoporous CoFe2O4/Co3Fe7@carbon prepared by clean and facile mechanochemical-molten salt process is employed as a trifunctional magnetic adsorbent-photocatalyst agent (M-APh) for the efficient adsorption of potassium ethyl xanthate (KEX) from its solutions in dark, and the photocatalytic degradation of the compound under LED-light irradiation. The surface- and bulk‑carbon content of M-APh is evaluated to be around 88 and 80 wt%, with the surface area of 355 m2/g and the average pore size of 3.7 nm, enabling the adsorption of 6.12 wt% KEX on its surfaces in dark. The ferromagnetic performance of M-APh, characterized by the coercivity (Hc), saturation magnetization (Ms) and remnant (Mr) values of 735 Oe, 17.9 emu/g and of 6.1 emu/g, respectively, is an asset supporting the facile separation of the agent from its suspensions. The effects of various parameters including the concentration of KEX in the solution, the dosage of M-APh, the wavelength of the LED-light, and the initial pH on the KEX removal performance of M-APh are studied. Within 5 h of LED-light irradiation of wavelengths 450, 385 and 365 nm, the KEX removal rates are recorded at 96.59, 98.61 and 99.49 %, respectively. Possible mechanisms involved in the adsorption and photocatalytic degradation of KEX are discussed.

AFM Image Analysis of the Adsorption of Xanthate and Dialkyl Dithiophosphate on Chalcocite

Atomic force microscopy (AFM) has been applied to study the adsorption morphology of various collectors, i.e., potassium ethyl xanthate (KEX) and potassium amyl xanthate (PAX) and Cytec Aerofloat 238 (sodium dibutyl dithiophosphate), on chalcocite in situ in aqueous solutions. The AFM images show that all these collectors adsorb strongly on chalcocite. Xanthate adsorbs mainly in the form of insoluble cuprous xanthate (CuX), which binds strongly with the mineral surface without being removed by flushing with ethanol alcohol. This xanthate/chalcocite adsorption mechanism is very similar to the one obtained with the xanthate/bornite system; while it is different from the one of the xanthate/chalcopyrite systems, for which oily dixanthogen is the main adsorption product on chalcopyrite surface. On the other hand, dibutyl dithiophosphate adsorbs on chalcocite in the form of hydrophobic patches, which can be removed by rinsing with ethanol alcohol. AFM images show that the adsorption of collectors increases with increasing adsorption time and collectors’ concentration. In addition, increasing the solution pH to 10 does not prevent the adsorption of xanthate and Aerofloat 238 on chalcocite and the result is in line with the fact that chalcocite floats well in a wide pH range up to 12 with xanthate and dialkyl dithiophosphate being used as collectors. The blending collectors study shows that xanthate and dialkyl dithiophosphate can co-adsorb with both insoluble cuprous xanthate and oily Cu(DTP)2 (Cu dibutyl dithiophosphate) on a chalcocite surface. The present study helps to clarify the flotation mechanism of chalcocite in industry practice using xanthate and dialkyl dithiophosphate as collectors.

The effect of experimental conditions on the formation of dixanthogen by triiodide oxidation in the determination of ethyl xanthate by HPLC–ICP-MS/MS

The rising concern over the environmental impact of xanthates, especially in the arctic region, has increased the need to study these traditional flotation reagents in greater detail. The environmental concern relates mostly to the formation of carbon disulfide (CS2) and the heavy metal complexes of xanthates. Due to the unstable nature and multiple reaction mechanisms of xanthates, their reliable determination at low concentration levels is difficult. In this study, a xanthate pretreatment method was optimized and applied for the determination of ethyl xanthate (EX−) by high performance liquid chromatography–inductively coupled plasma tandem mass spectrometry (HPLC–ICP-MS/MS). Ethyl xanthate was oxidized to diethyl dixanthogen ((EX)2) by triiodide (I3−) in aqueous solution and the formed (EX)2 was extracted into n-hexane. Important experimental parameters, including pH, I3− amount, and oxidation time, were optimized and the detection limit of 0.29 mg L−1 for potassium ethyl xanthate was obtained. During the optimization experiments, it was found that the oxidation reaction resulted in multiple products, decreasing the efficiency of (EX)2 formation and, therefore, the sensitivity of the method. The proposed method was applied to wastewater samples with recoveries of 105–106%. This study provides a selective method for the determination of ethyl xanthate and introduces novel information on the parameters affecting the oxidation of xanthates.Graphical abstract

Effect of strong collectors and frothers on coarse particle flotation using the HydroFloat™ for a North American concentrator

ABSTRACT In conventional flotation, particles larger than 150 μm tend to float poorly, especially those with high specific gravity. The flotation equipment, HydroFloat™, has been implemented in the mining industry and has resulted in significant improvements in coarse particle recovery, particularly when used with strong collectors and frothers. A North American concentrator processing copper-molybdenum (Cu-Mo) ore has been having difficulties in recovering particles coarser than 150 μm. Presently, the concentrator uses sodium ethyl xanthate and X-133 frother (baseline). Previous tests conducted using stronger collectors and frothers showed that potassium amyl xanthate (PAX) and FrothPro 630 increased Cu recovery by 3% using a conventional laboratory flotation machine. In that testwork, chalcopyrite recovery for particles > 300 μm was low (~55%) under a range of testing conditions. Thus, the HydroFloat™ was tested using potassium ethyl xanthate and PAX in an attempt to increase Cu recovery for particles > 300 μm. Results showed that the recovery of chalcopyrite particles > 300 μm increased by more than 10%, depending on the test condition.

Study of gold ore processing by flotation methods

The article deals with the studies of gold-bearing ore benefication by flotation methods. The object of the study is a low-sulfide gold-quartz type of ores with the following petrographic composition: quartz – 90 %, quartz-chlorite schists – 10 %. The ore from this deposit consists of the weathering crust rocks including iron-mica rocks with veins and spots of granoblastic quartz. The purpose of the research is to develop an optimal flotation regime for obtaining sulfide gold-bearing concentrate. The influence of ore size, reagent mode, flotation redistribution structure, and flotation time on operations was recorded during the experiment. The paper presents the results of studying the chemical composition of the ore by the method of silicate and optical emission analysis. The flotation process used butyl potassium xanthate as a collector and a combination of pine essential oils as a foaming agent. The Hancock concentration efficiency criterion was determined based on a series of experiments. The following technological indicators of ore processing were identified: gravity concentrate with the gold grade of 1165 g/t with the yield of 0.3 % and the recovery of 73.74 %; flotation concentrate (after purification II) with the gold grade of 68.9 g/t with the yield of 1.52 % and a recovery of 22.05 %. Its silver content was 15.9 g/t. The total gold recovery was 95.79 %, with the yield of 1.82 % and the gold grade of 249.9 g/t. The gold grade in the flotation tailings was 0.19 g/t.

Selective separation of chalcopyrite from pyrite using an acetylacetone-based lime-free process

• Acetylacetone (AA) can selectively collect chalcopyrite from pyrite without lime at pH 9.0. • Fe atoms on chalcopyrite surface interact with AA to form a six-membered ring complex. • The reactivity of Fe atoms on chalcopyrite surface is higher than that on pyrite surface. • The adsorption energy of AA on chalcopyrite is greater than that on pyrite. In the flotation separation of chalcopyrite and pyrite, the commonly used high-lime process often causes problems such as losses of precious metals, blockage in pipelines and environmental pollution. In this study, acetylacetone (AA) was used as a novel collector to separate chalcopyrite from pyrite without adding limes. The flotation results indicate that AA can selectively separate chalcopyrite from pyrite without depressants at pH 9.0. Flotation kinetics and entrainment calculations show that compared with potassium ethyl xanthate (KEX), AA reduces pyrite entrainment and produces the concentrate with a higher Cu grade and a higher separation efficiency. Solution chemistry calculations show that enolate (AAE - ) and ketone (AAK) are the dominant species of AA at pH 9.0. Contact angle measurements, zeta potential measurements and Fourier transform infrared (FTIR) analysis indicate that the dominant species of AA chemically adsorb onto chalcopyrite surfaces at pH 9.0 while the adsorption on pyrite is minimal. Density functional theory (DFT) analysis reveals that the Fe atoms on chalcopyrite are the active sites interacting with AA to form six-membered ring complexes. The selective adsorption of AA relies on the spatial distribution and reactivity of Fe atoms on the commonly exposed cleavage surfaces of chalcopyrite and pyrite. After surface relaxation, a layer of Fe atoms appears on the outermost layer of chalcopyrite (1 1 2) surface, which is beneficial for the adsorption of AA species while a layer of S atoms for pyrite (1 0 0) surface. The Fe (III) on chalcopyrite (1 1 2) surface has a higher reactivity than the Fe (II) on pyrite (1 0 0) surface, leading to a higher adsorption energy of AA species on the chalcopyrite. Therefore, this acetylacetone-based lime-free process has a great potential for industrial application in the separation of chalcopyrite from pyrite.

Dimerization of 3-Chlorooxindoles Mediated by Potassium Ethyl­xanthate: Synthesis of Isoindigos

AbstractA novel dimerization of 3-chlorooxindoles promoted by potassium ethylxanthate to access isoindigo derivatives is described. The reactions proceeded readily at room temperature in short reaction times. A mechanistic study revealed that the 3-chlorooxindole is initially converted into O-ethyl S-(2-oxo-2,3-dihydro-1H-indol-3-yl) dithiocarbonate, which subsequently undergoes dimerization with elimination of carbon disulfide. In almost all cases, analytically pure isoindigos were isolated in moderate to good yields without a requirement for chromatographic purification.

Depression Effect of Thioglycolic Acid (TGA) on Flotation Separation of Molybdenite from Copper Sulfides with different Collectors: An Experimental and Theoretical Study

AbstractIn the present study, the depression effect of thioglycolic acid (TGA) on chalcopyrite and pyrite in the presence of different collectors, including potassium ethyl xanthate (PEX), sodium isopropyl xanthate (SIPX), and mercaptobenzothiazole (MBT) in the flotation separation of molybdenite from copper and iron sulfide minerals was evaluated by micro‐flotation and bench‐scale flotation experiments. Surface characterization and adsorption mechanism were investigated by the density functional theory (DFT) method. The flotation experiment results demonstrated that the depression effect of TGA depends on the type of collector applied in the previous stages. DFT calculation provided strong evidence for the results of experiments. It was found that both chalcopyrite and pyrite were effectively depressed in the selective flotation of molybdenite from copper and iron sulfides by TGA when PEX was used as the collector in the bulk flotation stage. It was also found that the use of MBT causes effective flotation of chalcopyrite and molybdenite in the bulk flotation stage, however, its removal from the mineral surface by TGA was not as convenient as PEX.

Degradation of potassium alkyl xanthogenate in wet air oxidation: Enhancement method, degradation mechanism and structure impact

Wet air oxidation (WAO) is suitable for high concentration organic wastewater treatment, but the oxidation efficiency still needs to be improved and the reaction mechanism is not clear. This work explored the enhancement of different chemicals to the WAO of typical pollutants in metallurgical wastewater and found that persulfate promoted WAO (PWAO) is very efficient in mineralization of potassium ethyl xanthate. The degradation rate and COD removal rate was over 99% and 96% after 30 min reaction, respectively. The oxidation of alkyl xanthate followed the pseudo first-order kinetics, with the constant order of potassium amyl xanthate > potassium ethyl xanthate > potassium butyl xanthate > potassium isopropyl xanthate. The EPR result confirmed that hydroxyl radicals (·OH) was the dominant active species in the WAO and PWAO processes, and persulfate significantly increased the production of ·OH. It was found that the electrophilic reactivity s-(1S) of the S atom in the -CS and the lipophilic coefficient ClgP of xanthate were the main factors affecting the degradation of xanthate, by constructing a quantitative structure–activity relationship model. The results reveal that PWAO can be used in efficient degradation of flotation reagents, based on which a green metal leaching process and simultaneous organics degradation can be possibly developed in future.

Enhanced degradation of residual potassium ethyl xanthate in mineral separation wastewater by dielectric barrier discharge plasma and peroxymonosulfate

• DBD was used to activate PMS for synergetic degradation of residual PEX. • Approximately 90.5% of PEX was achieved in the DBD/PMS system. • SO4-, O· H, O2– and 1O2 contributed to PEX degradation especially ·SO4- and O· H. • The addition of PMS increased the dissolved O3 and H2O2 concentration. In the study, dielectric barrier discharge (DBD) plasma was used to activate peroxymonosulfate (PMS) for synergetic degradation of residual potassium ethyl xanthate (PEX) in mineral separation wastewater. The degradation efficiency of PEX in the combined system was obviously higher, indicating that the system had a significant synergistic effect on PEX degradation. After 25 min, approximately 90.5% of PEX and 1.637 of synergetic factors were achieved in the DBD/PMS system at 27.5 kV. The increase of PMS concentration resulted in the balance between the consumption and formation reaction of active species. The degradation efficiency of PEX under acidic conditions was higher. The addition of Cl - , CO3 2– and HA had an inhibition effect on PEX degradation due to the consumption of ·OH and ·SO4 - , and the presence of Cu 2+ promoted PEX degradation. The introduction of EtOH had a significant inhibitory effect, indicating that ·SO4 - and ·OH played a crucial part. The addition of PMS increased the dissolved O3 and H2O2 concentration in the combined system. The COD degradation and TOC mineralization efficiency gradually improved with the extension of treatment time for actual xanthate wastewater. A possible degradation pathway of PEX was proposed based on the degradation products.

Flotation behavior of a complex lead-zinc ore using individual collectors and its blends for lead sulfide

The effect of the collector and its blends on sequential flotation of a complex lead-zinc ore has been investigated. Lead-zinc ore collected from Rajasthan, India showed the presence of PbS-2.21%, ZnS-5.92%, FeS2-8.03%, SiO2-20.21%, Al2O3-5.25%, MgO-10.53%, SO3-6.48% and CaO-22.16%. The copper and silver were also traced as minor fractions. Xanthates of different alkyl chain lengths as a collector (individual or mixture in various proportions) were used in the lead circuit to evaluate valuables’ performance in the mineralized pulp. The study could enhance the lead and zinc grade up to 27.95% and 22.6% using PEX (potassium ethyl xanthate) and SIPX (sodium isopropyl xanthate) as a blend. The best overall performance in the recovery of lead and zinc was 74.39% and 82.23%, respectively. However, the studies carried out with individual collectors, PEX and SIPX, showed their best result: 22.06% lead and 20.99% zinc grade, 60.54% lead, and 78.73% zinc recovery. The study confirms the synergies between the two alkyl chain length xanthates in the blend.

Determination of Ethyl Xanthate in Aqueous Solution by High Performance Liquid Chromatography–Inductively Coupled Plasma–Tandem Mass Spectrometry and Spectrophotometry

Xanthates are commonly used collectors in flotation processes but are highly toxic to the aquatic environment. However, there are few methods for reliable determination of low xanthate concentrations in water samples. In this work, a sensitive, selective, and fast method is presented for the determination of potassium ethyl xanthate (KEX). KEX was determined by high-performance liquid chromatography–inductively coupled plasma–mass spectrometry (HPLC-ICP-MS/MS) directly and as diethyl dixanthogen [(EX)2] after oxidation with triiodide. The HPLC method was optimized for (EX)2 and the separated compounds were detected by ICP-MS/MS. The ICP-MS/MS was used in mass-shift mode using O2 as the cell gas and S+ was measured as SO+ to reduce spectral interferences. Detection limits of 88 µg L−1 for KEX and 20 µg L−1 for (EX)2 calculated from the peak area were obtained using mass-shift 32S+ → 32S16O+. No significant matrix effects were present when spiking experiments of (EX)2 were done to a sample collected from the tailings of a flotation process. The developed method demonstrates the potential of the HPLC-ICP-MS/MS for the determination of ethyl xanthate. This method may be extended to analyzing other xanthates and similarly structured sulfur containing collectors.

Computational Study on Production Mechanism of Nano-Graphene Oxide/Poly Diallyl Dimethyl Ammonium Chloride (NGO/PDADMAC) Nanocomposite

Nanographene oxide (NGO) is one of the most attractive carbon nanomaterials, which due to its high surface-to-mass ratio and epoxy functional groups on the plate, carboxy and hydroxy on the edges, is easily dispersed in water and is one of the most effective materials for the surface adsorbent. Poly diallyl dimethyl ammonium chloride (PDADMAC) nanocomposite with nano-graphene oxide (NGO/PDADMAC) is used to treat pollutions of negatively charged colloidal materials in water. To form nano-composite with diallyl dimethyl ammonium chloride monomer in the form of live radical polymerization, are used two intermediates of 2-bromopropyl bromide (BPB) and potassium ethyl xanthate (EX). In this study, nano-graphene oxide is exposed to 2-bromopropionyl bromide (NGO/BPB), is investigated the possibility of interacting with three functional groups (carboxy, hydroxy, and proxy) of the graphene oxide nano-sphere. Potassium ethyl xanthate (EX) and Poly diallyl dimethyl ammonium chloride are then added to their nano-complex (NGO/BPB). Thermodynamic and structural parameters based on B3LYP/6-31 + G** show that the structure of the complex created in the carboxy and hydroxy positions has better structural properties than the epoxy group, with comparing of the groups in the IR spectra of experimental and computational, is more the probability of overlap the hydroxy agent. The thermodynamic, structural, and computational parameters indicate the possibility of forming a composite with the hydroxy agent group to be used as filler.

CuI/L‐proline‐catalyzed synthesis of bis(2‐(4,5‐diaryl‐1H‐imidazol‐2‐yl)phenyl)sulfane derivatives using potassium ethylxanthate as a sulfur source

AbstractA CuI/L‐proline‐catalyzed reaction of 2‐(2‐bromophenyl)‐4,5‐diaryl‐1H‐imidazole and potassium ethylxanthate unexpectedly gave bis(2‐(4,5‐diaryl‐1H‐imidazol‐2‐yl)phenyl)sulfane derivatives in high yields, rather than 2,3‐diphenyl‐5H‐benzo[e]imidazo[1,2‐c]thiazine‐5‐thione. This cascade procedure provided an efficient method to synthesize diphenylsulfanes using potassium ethylxanthate as a new type of sulfur source via the Csp2S bond Ullmann reaction twice.

Synthesis and study of aroylethyl(ethyl)-xanthates as stabilizers of polymeric materials

The number of aroylethyl (ethyl)xanthates have been synthesized by the reaction of the exchange decomposition of β-dimethylaminopropiophenone hydrochlorides with potassium xanthate containing several functional groups (C=O, C=S, C–OH), which determine the use of these xanthates as stabilizers with internal synergy to polymeric materials. It was shown that the thermal stability of the compounds, depending on the nature of the substituent in the benzene ring of the molecule was observed in the temperature range of 149–196 °C. It was revealed that aroylethyl(ethyl)xanthates had a stabilizing effect due to the suppression of thermo-oxidative destruction of polyethylene; they increased the induction period of polyethylene oxidation by 2–6 times, and the oxidation rate was reduced by about 3–9 times. Among the studied compounds, 4-hydroxybenzoylethyl (ethyl)xanthate had the greatest stabilizing effect. The study of the mechanism of the stabilizing action of the compounds showed that xanthates react with cumene hydroperoxide (CHP), which proceeded through the stage of formation of an intermediate product that actively decomposed CHP, i.e., the oxidation chain was terminated by the decomposition of the CHP not by the initial xanthates but by their transformation products.

Selective depression of millerite (β-NiS) by polysaccharides in alkaline solutions in Cu-Ni sulphides flotation separation

The presence of a nickel sulphide mineral – millerite (β-NiS) has a significant impact on the Cu/Ni flotation separation efficiency in the plant operations. In this study, the feasibility of using corn dextrin as a representative of polysaccharides to depress millerite (β-NiS) in the differential Cu-Ni sulphides flotation at pH 9 and pH 12 was examined. Micro-flotation tests showed that dextrin can depress xanthate-treated millerite without deteriorating chalcopyrite (CuFeS2) recovery when using potassium ethyl xanthate (KEX) as a collector, resulting in efficient Cu/Ni separation at both pH 9 and pH 12. X-ray photoelectron spectroscopy (XPS) analysis revealed that dextrin adsorption on millerite at alkaline pH was identified as a chemisorption process. Dextrin’s hydroxyl functional group can interact with the metal hydroxide on the mineral surface. At pH 12, dextrin can adsorb on xanthate-treated millerite while negligible adsorption was observed on xanthate-treated chalcopyrite. Mineral dissolution tests and ethylenediaminetetraacetic acid (EDTA) extraction tests suggested the preferential adsorption of dextrin on millerite over chalcopyrite might be associated with the predominant passivation layer of nickel hydroxide formed on the millerite surface at alkaline pH due to the extensive nickel dissolution. Atomic force microscopy (AFM) imaging was used to visually investigate the adsorption of dextrin on millerite and xanthate-treated chalcopyrite at pH 12. Overall, this study provided a feasible depression strategy for millerite in the copper concentrate using a cost-effective and environmental-friendly reagent.

An Investigation of the Adsorption of Xanthate on Bornite in Aqueous Solutions Using an Atomic Force Microscope

An atomic force microscope (AFM) was applied to study of the adsorption of xanthate on bornite surfaces in situ in aqueous solutions. AFM images showed that xanthate, i.e., potassium ethyl xanthate (KEX) and potassium amyl xanthate (PAX), adsorbed strongly on bornite, and the adsorbate bound strongly with the mineral surface without being removed by flushing with ethanol alcohol. The AFM images also showed that the adsorption increased with the increased collector concentration and contact time. Xanthate adsorbed on bornite in a similar manner when the solution pH changed to pH 10. The AFM force measurement results showed that the probe–substrate adhesion increased due to the adsorption of xanthate on bornite. The sharp “jump-in” and “jump-off” points on force curve suggest that the adsorbate is not “soft” in nature, ruling out the existence of dixanthogen, an oily substance. Finally, the ATR-FTIR (attenuated total reflection-Fourier-transform infrared) result confirms that the adsorbate on bornite in xanthate solutions is mainly in the form of insoluble cuprous xanthate (CuX) instead of dixanthogen. This xanthate/bornite adsorption mechanism is very similar to what is obtained with the xanthate/chalcocite system, while it is different from the xanthate/chalcopyrite system, for which oily dixanthogen is the main adsorption product on the chalcopyrite surface. The present study helps clarify the flotation mechanism of bornite in industry practice using xanthate as a collector.

The copper-catalyzed synthesis of (Z)-2H-naphtho[1,8-bc]thiophenes with solid emission.

In recent years, one of the main research interests of our group has been the construction of 6/5 π-systems through the regioselective conversion of parallel alkynes in naphthalene with the aim of exploiting potential fluorescent materials. Herein, the copper-catalyzed synthesis of polysubstituted (Z)-2H-naphtho[1,8-bc]thiophenes from 8-halo-1-ethynylnaphthalenes using potassium ethylxanthate as the sulfur source is reported. In this protocol, a series of thiophene-fused 6/5 π-system compounds was synthesized via copper-catalyzed Ullmann-type C(aryl)-S bond formation and the α-addition of an alkyne bond with high selectivity and in high yields. The synthesized polysubstituted (Z)-2H-naphtho[1,8-bc]thiophenes exhibited solid emission, which made them potential candidates for use in optoelectronic conjugated materials. By using DMSO/D2O (3 : 1) as the reaction solvent, the deuterated products could be obtained in good yields under standard conditions.

Transition Metal‐Free Synthesis of Substituted Isothiazoles via Three‐Component Annulation of Alkynones, Xanthate and NH4I

AbstractA protocol was described to access diverse isothiazoles with functionalization potential via transition metal‐free three‐component annulation of alkynones, potassium ethylxanthate (EtOCS2K) and ammonium iodide (NH4I). A sequential regioselective hydroamination/thiocarbonylation/intramolecular cyclization cascade achieved the efficient formation of consecutive C−N, C−S and N−S bonds in a one‐pot process.magnified image