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.
Interactions between Sulphide Minerals and Alkylxanthate Ions Part 1.-A Vibrational Spectroscopic Study of the Interactions between Sphalerite and Synthetic Zinc(II) and Cadmium(II) Sulphides, and Ethylxanthate Ions in Aqueous and Acetone Solutions
Persson, Per,Malmensten, Bo,Persson, Ingmar
, p. 2769 - 2777 (1991)
The crystal structures of zinc(II) and cadmium(II) sulphides are not affected by the stoichiometry of metal and sulphide ions at the precipitation of the two compounds.The composition and structure of the ultimate surface layers, and thereby the chemical properties of the particles, are on the other hand sensitive to the stoichiometry at the preparation.Chemisorbed ethylxanthate complexes are formed at metal ion sites on the surfaces of sphalerite and synthetic zinc(II) and cadmium(II) sulphides at metal and ethylxanthate ion concentrations where the solubility product of zinc(II) or cadmium(II) ethylxanthate is not exceeded.Two different types of ethylxanthate species co-ordinated to the surfaces have been found.These have been assigned to mono- and bi-dentate co-ordination of the ethylxanthate ion to the surface.Surface complexes are most probably enthalpy stabilized, and the bond(s) between the metal ion site in the surface and the ligand must contain some degree of covalency, as the entropy contribution to the formation of a chemisorbed complex on a surface is small.The stability of complexes of this kind is expected to increase with increasing softness of metal site and ligand.This is indicated as the ethylxanthate and EDTA surface complexes on cadmium(II) sulphide seem to be more stable than the corresponding complexes on zinc(II) sulphide surfaces.The stability of the surface complex is dependent on the solvent used, and seems to be a function of the solvation properties of the solvent.
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.
Synthesis of CO2-philic xanthate-oligo(vinyl acetate)-based hydrocarbon surfactants by RAFT polymerization and their applications on preparation of emulsion-templated materials
Chen, Keping,Grant, Neil,Liang, Liyun,Zhang, Haifei,Tan, Bien
, p. 9355 - 9364 (2010)
Amphiphilic block copolymers poly(ethylene glycol)-block-oligo(vinyl acetate) (PEG-b- OVAc) and OVAc-b-PEG-b-OVAc have been demonstrated to be effective surfactants for CO2-in-water (C/W) emulsions. However, the high cost and difficulty of synthesis process can render the economics of CO2 process unfavorable. In this work, by reversible addition-fragmentation chain transfer (RAFT) polymerization, a series ofwell-defined CO2-philic triblock copolymers X-OVAc-b-PEG-b-OVAc- X(whereXstands for xanthate group) were synthesized. The structures and molecular weights of these copolymers were characterized by 1H NMRand GPC. The results of GPC analysis exhibited relatively narrow polydispersity (PDI1.35). The process of preparation of X-OVAc-based surfactants was much more simple, inexpensive and also easy to control, which could promote industrial-scale applications. The X-OVAc-based surfactants were found effectively to produce highly concentrated stable C/W emulsions. Porous emulsion-templated materials were prepared by the polymerization of the continuous phase of C/W emulsions. The open-cell morphology of the emulsion-templated materials was evidenced by scanning electron microscope. To tune the morphology of the porous structures, the influence of the surfactant concentration and molecular weight ofOVAcblock were also investigated. It was shown that X-OVAc-based surfactants can outperform perfluorinated surfactants and approach OVAc-based surfactants for such applications.
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.
Polyvinyl alcohol as a biocompatible alternative for the passivation of gold nanorods
Kinnear, Calum,Burn, David,Clift, Martin J. D.,Kilbinger, Andreas F. M.,Rothen-Rutishauser, Barbara,Petri-Fink, Alke
, p. 12613 - 12617 (2014)
The functionalization of gold nanorods (GNRs) with polymers is essential for both their colloidal stability and biocompatibility. However, a bilayer of the toxic cationic surfactant cetyl trimethylammonium bromide (CTAB) adsorbed on the nanorods complicates this process. Herein, we report on a strategy for the biocompatible functionalization of GNRs with a hydrophobic polymeric precursor, polyvinyl acetate, which is then transformed into its hydrophilic analogue, polyvinyl alcohol. This polymer was chosen due to its well-established biocompatibility, tunable "stealth" properties, tunable hydrophobicity, and high degree of functionality. The biocompatibility of the functionalized GNRs was tested by exposing them to primary human blood monocyte derived macrophages; the advantages of tunable hydrophobicity were demonstrated with the long-term stable encapsulation of a model hydrophobic drug molecule.
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.
Visible-Light-Driven MADIX Polymerisation via a Reusable, Low-Cost, and Non-Toxic Bismuth Oxide Photocatalyst
Hakobyan, Karen,Gegenhuber, Thomas,McErlean, Christopher S. P.,Müllner, Markus
, p. 1828 - 1832 (2019)
The continuous amalgamation of photocatalysis into existing reversible deactivation radical polymerisation (RDRP) processes has initiated a rapidly propagating area of polymer research in recent years. We introduce bismuth oxide (Bi2O3) as a heterogeneous photocatalyst for polymerisations, operating at room temperature with visible light. We demonstrate formidable control over degenerative chain-transfer polymerisations, such as macromolecular design by interchange of xanthate (MADIX) and reversible addition-fragmentation chain-transfer (RAFT) polymerisation. We achieved narrow molecular weight distributions and attribute the excellent temporal control of a photo-induced electron transfer (PET) process. This methodology was employed to synthesise diblock copolymers combining differently activated monomers. The Bi2O3 catalyst system has the additional benefits of low toxicity, reusability, low-cost, and ease of removal from the reaction mixture.
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.
