140-89-6Relevant articles and documents
Spectroscopic characterization of ethyl xanthate oxidation products and analysis by ion interaction chromatography
Hao, Fu Ping,Silvester, Ewen,Senior, Geoffrey David
, p. 4836 - 4845 (2000)
An ion interaction chromatographic separation method, coupled with UV spectroscopic detection, has been developed for the analysis of ethyl xanthate (O-ethyl dithiocarbonate) and its oxidative decomposition products in mineral flotation systems. The effects of the ion-pairing agent (tetrabutylammonium ion), pH modifier (phosphoric acid), and organic modifier (acetonitrile) in the eluant upon the retention characteristics of the ethyl xanthate oxidation products have been determined. The optimized separation procedure has been successfully applied to the analysis of ethyl xanthate and its oxidation products in a nickel-iron sulfide mineral suspension containing a number of other anionic species, including cyanide complexes of nickel and iron, as well as sulfur-oxy anions. The ethyl xanthate oxidation products investigated in this study have been isolated as pure compounds and characterized by UV-visible, FT-IR, and NMR spectroscopies. The UV-visible and FT-IR spectroscopic properties of these species are discussed in terms of the chemical modifications of the thiocarbonate group.
VIBRATIONAL ANALYSIS OF ALKYL XANTHATES
Colthup, N. B.,Powell, L. Porter
, p. 317 - 322 (1987)
Rotational isomers are indicated in the Raman spectra of sodium ethyl and other xanthates.Vibrational bands useful for characterizing xanthate solids and aqueous solutions are given.Vibrational analyses are reported for sodium ethyl xanthate, trans and gauche forms, and the methyl and isopropyl analogs using a Cartesian coordinate force field derived from ab initio molecular orbital calculations.
Syntheses, structures, and electrochemical studies of N,N′-bis(alkylthiocarbamate)butane-2,3-diimine Cu(II) complexes as pendent alkoxy derivatives of Cu(ATSM)
Vishnosky, Nicholas S.,Mashuta, Mark S.,Buchanan, Robert M.,Grapperhaus, Craig A.
, p. 45 - 51 (2017)
A series of N2S2-Cu(II) complexes based on N,N′-bis(alkylthiocarbamate)butane-2,3-diimine ligands have been synthesized and characterized by spectroscopic, electrochemical, and single crystal X-ray diffraction methods. This class of ligands contains a conjugated N2S2chelate framework with a non-coordinating, terminal alkoxy (–OR) group. Ligands and Cu(II) complexes were investigated for R = Me, Et,nPr,iPr, and octyl. Additionally, N,N′-bis(ethylthiocarbamate)hexane-3,4-diimine and its Cu(II) complex were analyzed. Single crystal X-ray diffraction studies on all six Cu(II) complexes confirm a square planar Cu(II) environment with no significant changes in the core structure as a function of R. Spectroscopic studies are consistent with a similar electronic environment in all complexes. However, electrochemical investigations reveal significant shifts in the CuII/Iand CuIII/IIreduction potentials throughout the series. The complexes are analogues of the well-known bis(thiosemicarbazone) Cu(II) which contain a similar donor core with terminal, non-coordinating amines. Substitution of the terminal amines of bis(thiosemicarbazones) with the alkoxy groups of N,N′-bis(alkylthiocarbamate)butane-2,3-diimines allows tuning of redox potentials with minimal changes in the physical and electronic structure.
1-Alkyl-4-ethoxythiocarbonyl-5-hydroxy-3-methylpyrazole: Synthesis, copper complexes and solvent extraction studies
Oliva, Alfonso,Molinari, Aurora,Toro, Carolina
, p. 329 - 335 (2008)
1-Alkyl-4-ethoxythiocarbonyl-5-hydroxy-3-methylpyrazole, HETCP, (alkyl = n-octyl ; n-dodecyl) were prepared in high yield by the reaction of 1-alkyl-3-methyl-2-pyrazolin-5-one with bis (ethoxythiocarbonyl)sulfide and sodium acetate in dimethylformamide. These reagents act as O, S bidentate ligands in solvent extraction/reextraction studies of Cu (II) from acid aqueous solutions and the extracted specie resulted to be Cu(ETCP)2.
One-pot synthesis and methylation of 3-[2-(1 H -benzimidazol-2-yl-sulfanyl) -acetyl]-chromen-2-ones
Tasqeeruddin,Dubey
, p. 128 - 134 (2012)
3-(2-Bromoacetyl)coumarins (I), when treated with 2-mercatobenzimidazole (II) in acetone containing K2CO3 (mild base) and tetrabutylammonium bromide (TBAB) as a phase transfer catalyst, at room temperature yielded the title compound 3-[2-(1H-benzimidazole-2-yl-sufanyl)- acetyl]-chromen-2-one (III) in a one-pot synthesis. Alternatively, III could also be prepared by treating dithiocarbonic acid O-ethyl ester, S-[2-oxo-2-(2-oxo-2H-chromen3-yl)-ethyl] ester (V), with o-phenylenediamine (VI). The methylation of the title compound III was performed with dimethyl sulfate (DMS), in acetonitrile containing TBAB and K2CO3 at room temperature, resulting in 3-[2-(N-methyl-benzimidazol-2-yl-sulfanyl)]- acetyl-chromen-2-ones (VII). Alternatively, methylation of III could also be performed with DMS in acetonitrile containing K2CO3 as base and clay as surface catalyst. All the compounds were synthesized in good yields and their structures were confirmed by spectral and analytical data. [Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements for the following free supplemental resource: 1H NMR of IIIB, VB and VIIB] Copyright Taylor and Francis Group, LLC.
Amphiphilic poly(N-vinyl pyrrolidone) grafted graphene by reversible addition and fragmentation polymerization and the reinforcement of poly(vinyl acetate) films
Layek, Rama K.,Kuila, Atanu,Chatterjee, Dhruba P.,Nandi, Arun K.
, p. 10863 - 10874 (2013)
The reversible addition and fragmentation (RAFT) polymerization of vinyl pyrrolidone (VP) from graphene oxide (GO) is used to produce GO-g-PVP (GP) and the grafting is confirmed from Fourier transformed infrared (FTIR) and nuclear magnetic resonance spectra. The average thickness of GP (8.2 nm) obtained from atomic force microscopy is higher than that of GO (1.2 nm), indicating the wrapping of grafted PVP on the GO sheets. Transmission electron microscopy of GP exhibits swollen domains (white spots) characterizing the grafted PVP chains from the GO surface. The dispersibility of the GP sheets becomes greatly improved over that of GO and they are dispersible in the solvents of Hansen solubility parameter (δp + δH) range 6.3-58. Three nanocomposites GP1, GP3 and GP5, produced by mixing with 1, 3 and 5 (w/w)% GP with poly(vinyl acetate) (PVAc), produce a stable dispersion in dimethyl formamide, although mixtures of GO and PVAc do not. The field emission scanning electron microscopy of the GP5 sample indicates a good homogeneous dispersion of GP sheets within the PVAc matrix, although both GO and PVP are individually immiscible with PVAc. The FTIR data indicates a specific interaction between GP and PVAc. The glass transition temperature (Tg) of the pure PVAc increases in the GP composites, but in the GO composite it remains unchanged. In the GPP5 hybrid containing the GO, PVP and PVAc mixture produced at the same composition as in GP5, an increase of Tg is seen to a lesser degree than that of GP, indicating that GO acts as a compatibilizer of a PVP and PVAc immiscible blend. The mechanical properties of PVAc exhibit a strong reinforcement and the Young's modulus & tensile strength data show a 190% and 169% increase over PVAc in the GP5 sample due to the homogenous dispersion and unidirectional (parallel) orientation of GP sheets in the composite film.
Synthesis of oligomer vinyl acetate with different topologies by RAFT/MADIX method and their phase behaviour in supercritical carbon dioxide
Zhang, Shoucun,Chen, Keping,Liang, Liyun,Tan, Bien
, p. 5303 - 5309 (2013)
Poly(vinyl acetate) (PVAc) has been shown to exhibit anomalously high solubility in CO2 as compared to other vinyl hydrocarbon polymers. Understanding the phase behaviour of PVAc with different topologies in CO 2 is very important for its potential applications as suitable surfactant, or phase transfer agent in a CO2 solvent process. In this study, a series of PVAcs with different topologies (bi-arms, tri-arms, tetra-arms) were synthesized by RAFT/MADIX method. The structures and molecular weights of these polymers were characterized by 1H NMR and GPC. The phase behaviours of PVAcs in dense carbon dioxide fluid were determined, and the results show that the PVAc with more arms has lower cloud point pressure.
Effect of ligands on crystallography, morphology and photo-catalytic ability of ZnS nanostructures
Kaur, Balwinder,Singh, Karamjit,Malik, Ashok Kumar
, p. 153 - 160 (2017)
ZnS nanostructures have been synthesized using zinc complexes: Zn(ethyl xanthate)2] & [Zn(morpholine4-dithiocarbamate)2] from ligands potassium ethyl xanthate (KEX) and morpholine4-dithiocarbamate (MDTC) by solvothermal route of synthesis. Crystallographic and morphological analyses of synthesized ZnS nanostructures have been done by X-ray diffraction (XRD) and electron microscopy [Transmission Electron Microscope (TEM)], respectively. Diffraction and electron microscope studies reveal the formation of hexagonal structured ZnS nanocrystals of various morphologies (nanosheets & nanorods). UV–vis. absorption studies have been carried for the detailed optical analyses. Photoluminescence (PL) study was carried out to check luminescence of synthesized ZnS nanostructures in blue region of electromagnetic spectrum. It has been reported that the morphology of synthesized nanostructures strongly depends upon the precursor complexes prepared from two different classes of ligands; potassium ethyl xanthate and morpholine4-dithiocarbamate. Photo-catalytic activity potential of the synthesized ZnS nanostructures has been tested in UV light using methylene blue (MB) dye as a test contaminant in aqueous media. About 88.49% and 87.96% of MB dye was photo-degraded by ZnS nanostructures synthesized from Zn(EX)2 [ where EX stands for ethyl xanthate] and Zn(MDTC)2, respectively.
Visible-Light-Induced Radical Carbo-Cyclization/ gem-Diborylation through Triplet Energy Transfer between a Gold Catalyst and Aryl Iodides
Hashmi, A. Stephen K.,Rominger, Frank,Si, Xiaojia,Zhang, Lumin
supporting information, p. 10485 - 10493 (2020/07/03)
Geminal diboronates have attracted significant attention because of their unique structures and reactivity. However, benzofuran-, indole-, and benzothiophene-based benzylic gem-diboronates, building blocks for biologically relevant compounds, are unknown. A promising protocol using visible light and aryl iodides for constructing valuable building blocks, including benzofuran-, indole-, and benzothiophene-based benzylic gem-diboronates, via radical carbo-cyclization/gem-diborylation of alkynes with a high functional group tolerance is presented. The utility of these gem-diboronates has been demonstrated by a 10 g scale conversion, by versatile transformations, by including the synthesis of approved drug scaffolds and two approved drugs, and even by polymer synthesis. The mechanistic investigation indicates that the merging of the dinuclear gold catalyst (photoexcitation by 315-400 nm UVA light) with Na2CO3 is directly responsible for photosensitization of aryl iodides (photoexcitation by 254 nm UV light) with blue LED light (410-490 nm, λmax = 465 nm) through an energy transfer (EnT) process, followed by homolytic cleavage of the C-I bond in the aryl iodide substrates.
Photochemical generation of acyl and carbamoyl radicals using a nucleophilic organic catalyst: Applications and mechanism thereof
Balletti, Matteo,De Pedro Beato, Eduardo,Mazzarella, Daniele,Melchiorre, Paolo
, p. 6312 - 6324 (2020/08/24)
We detail a strategy that uses a commercially available nucleophilic organic catalyst to generate acyl and carbamoyl radicals upon activation of the corresponding chlorides and anhydrides via a nucleophilic acyl substitution path. The resulting nucleophilic radicals are then intercepted by a variety of electron-poor olefins in a Giese-type addition process. The chemistry requires low-energy photons (blue LEDs) to activate acyl and carbamoyl radical precursors, which, due to their high reduction potential, are not readily prone to redox-based activation mechanisms. To elucidate the key mechanistic aspects of this catalytic photochemical radical generation strategy, we used a combination of transient absorption spectroscopy investigations, electrochemical studies, quantum yield measurements, and the characterization of key intermediates. We identified a variety of off-the-cycle intermediates that engage in a light-regulated equilibrium with reactive radicals. These regulated equilibriums cooperate to control the overall concentrations of the radicals, contributing to the efficiency of the overall catalytic process and facilitating the turnover of the catalyst. This journal is
