The interaction of the ethyl xanthate (EX) anion with a copper electrode in a borate buffer solution, pH 9.2, has been investigated by cyclic voltammetry (CV), electrochemical quartz crystal microbalance (EQCM), electrochemical impedance spectroscopy (EIS), and measurements of contact angle (CA) under controlled potential. The results obtained allow establishing that, in the potential range from -0.80 and -0.60 V, two parallel reactions were characterized. These reactions were the ethyl xanthate electroadsorption and the hydrogen evolution reaction (HER). This last reaction has not been described by previous authors. Besides, the EIS measurements show that the mechanism of the HER on copper electrodes is not affected by the presence of a ethyl xanthate species. The EQCM study shows that in the electrodesorption process the departure of each ethyl xanthate species from the copper electrode is accompanied with the simultaneous entry of four to five water molecules. This fact is in accordance with the number of copper atoms involved in the adsorption of one ethyl xanthate species.
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http://dx.doi.org/10.1021/jp054477e | DOI Listing |
Angew Chem Int Ed Engl
January 2025
School of Chemistry and Chemical Engineering, Shandong University, Jinan, 250100, China.
In this contribution, we designed a new xanthate RAFT agent by introducing (5,6,7,8-tetrahydro-2-naphthalenyl)oxy (TNO) as the Z group, namely 2-[(((5,6,7,8-Tetrahydro-2-naphthalenyl)oxycarbonothioyl)thio)ethyl propanoate] (TNXEP). Due to the presence of the TNO group, TNXEP enabled highly controlled and ultrafast photoiniferter RAFT polymerization under violet (λ=405 nm) and blue (λ=450 nm) light. This approach was effectively extended to aqueous media for polymerization-induced self-assembly (PISA), facilitating the synthesis of polymeric nanoparticles.
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January 2025
School of Resources, Environment and Materials, Guangxi University, Nanning 530004, China.
Ester collectors have rapidly developed into the main flotation collectors for copper sulfide minerals since they were developed. In this study, the collecting performance of four collectors, O-isopropyl-N-ethyl thionocarbamate ester (IPETC), 3-pentyl xanthate acrylate ester (PXA), O-isobutyl-N-allyl-thionocarbamate (IBALTC), and O-isobutyl-N-isobutoxycarbonyl-thionocarbamate (IBIBCTC), was investigated through microflotation tests, microcalorimetric measurements, and quantum chemical calculations. The results of the microflotation tests show that IBALTC and IPETC have stronger collecting abilities than IBIBCTC and PXA; the order of collecting ability is IBALTC > IPETC > IBIBCTC > PXA.
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December 2024
Syensqo, Centre de Recherche et Innovation Aubervilliers, 52 Rue de la Haie Coq, 93308 Aubervilliers Cedex, France.
Rhodixan A1 is the trade name for -ethyl -(1-methoxycarbonylethyl)dithiocarbonate, a RAFT/MADIX agent used by Syensqo to produce block copolymer additives for aqueous formulations on an industrial scale. Chain transfer coefficients to Rhodixan A1 determined for 25 different styrenic, acrylate, and acrylamide monomers were relatively low (0.6 < C < 3.
View Article and Find Full Text PDFAdv Mater
November 2024
College of Chemical and Biological Engineering, Zhejiang University, Hangzhou, 310027, China.
Lithium-sulfide (LiS) has long been pursued as a lithium-containing cathode material for high-energy-density lithium-sulfur (Li-S) batteries. Unfortunately, its direct oxidation generally has a large overpotential, giving rise to low energy efficiency. The use of redox mediators to accelerate the conversion of solid LiS to polysulfides represents a possible solution to lower the initial oxidation overpotential.
View Article and Find Full Text PDFPolymers (Basel)
August 2024
Industrial Chemistry Laboratory, Department of Chemistry, National and Kapodistrian University of Athens, Panepistimiopolis Zografou, 15771 Athens, Greece.
Amphiphilic block copolymers of N-vinyl pyrrolidone (NVP) and various vinyl esters (VEs), PNVP--PVEs, namely vinyl butyrate (VBu), vinyl decanoate (VDc), and vinyl stearate (VSt), were synthesized through RAFT polymerization techniques. The sequential addition of the monomers methodology was employed starting from the polymerization of NVP followed by the polymerization of the Ves' monomer. The polymerization of NVP was conducted at 60 °C in benzene solution using AIBN as the initiator and O-ethyl S-(phthalimidylmethyl) xanthate as the CTA.
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