The Experts below are selected from a list of 225 Experts worldwide ranked by ideXlab platform
Xuefeng Jiang - One of the best experts on this subject based on the ideXlab platform.
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sodium Dithionite mediated decarboxylative sulfonylation facile access to tertiary sulfones
Angewandte Chemie, 2020Co-Authors: Shihao Chen, Ming Wang, Xuefeng JiangAbstract:A straightforward multicomponent decarboxylative cross coupling of redox-active esters (N-hydroxyphthalimide ester), sodium Dithionite, and electrophiles was established to construct sterically bulky sulfones. The inorganic salt sodium Dithionite not only served as the sulfur dioxide source, but also acted as an efficient radical initiator for the decarboxylation. Notably, diverse naturally abundant carboxylic acids and artificially prepared carboxyl-containing drugs with multiple heteroatoms and sensitive functional groups successfully underwent this decarboxylative sulfonylation to provide sterically bulky tertiary sulfones. Mechanistic studies further demonstrated that decarboxylation was the rate-determining step and occurred via a single-electron transfer (SET) process with the assistance of sodium Dithionite.
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Sodium Dithionite‐Mediated Decarboxylative Sulfonylation: Facile Access to Tertiary Sulfones
Angewandte Chemie (International ed. in English), 2020Co-Authors: Shihao Chen, Ming Wang, Xuefeng JiangAbstract:A straightforward multicomponent decarboxylative cross coupling of redox-active esters (N-hydroxyphthalimide ester), sodium Dithionite, and electrophiles was established to construct sterically bulky sulfones. The inorganic salt sodium Dithionite not only served as the sulfur dioxide source, but also acted as an efficient radical initiator for the decarboxylation. Notably, diverse naturally abundant carboxylic acids and artificially prepared carboxyl-containing drugs with multiple heteroatoms and sensitive functional groups successfully underwent this decarboxylative sulfonylation to provide sterically bulky tertiary sulfones. Mechanistic studies further demonstrated that decarboxylation was the rate-determining step and occurred via a single-electron transfer (SET) process with the assistance of sodium Dithionite.
José M. Navaza - One of the best experts on this subject based on the ideXlab platform.
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Density and Viscosity of Aqueous Solutions of Sodium Dithionite, Sodium Hydroxide, Sodium Dithionite + Sucrose, and Sodium Dithionite + Sodium Hydroxide + Sucrose from 25 °C to 40 °C
Journal of Chemical & Engineering Data, 1996Co-Authors: Gonzalo Vázquez, Rocío Varela, And Angeles Cancela, Estrella Alvarez, José M. NavazaAbstract:The density and viscosity of aqueous solutions of sodium Dithionite, sodium hydroxide, sodium Dithionite + sucrose, and sodium Dithionite + sodium hydroxide + sucrose were measured at temperatures from (25 to 40) °C. The concentration ranges were (0 to 1.0) mol·dm-3 for sodium Dithionite, (0 to 1.0) mol·dm-3 for sodium hydroxide, and (0 to 171) g·dm-3 for sucrose. The experimental values were correlated with the concentration of sucrose. The maximum deviation was always less than 0.2%.
Philippe Westbroek - One of the best experts on this subject based on the ideXlab platform.
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electrocatalytic oxidation of Dithionite at a cobalt ii tetrasulfonated phthalocyanine and 5 10 15 20 tetrakis 4 sulfonatophenyl porphyrin cobalt ii modified gold electrode in alkaline solution
Electroanalysis, 2005Co-Authors: Karolien De Wael, Philippe Westbroek, Eduard TemmermanAbstract:In this paper it is shown that the charge transfer kinetics of the oxidation of sodium Dithionite at a gold electrode in alkaline solution can be increased by modifying this electrode with cobalt(II)tetrasulfonated phthalocyanine, sodium salt (CoTSPc) or 5,10,15,20-tetrakis-(4-sulfonatophenyl)porphyrin cobalt(II), tetrasodium salt (CoTSPor). Electrodeposition of these catalysts is discussed as well as the oxidation of sodium Dithionite at these immobilized catalysts. Despite an observed acceleration in the charge transfer kinetics, sodium Dithionite is still oxidized irreversibly. However, the improvement in kinetics has beneficial consequences in the field of electroanalysis of sodium Dithionite. Comparison of the oxidation at bare gold and modified gold electrodes showed that with improved charge transfer kinetics at the modified electrodes a higher sensitivity and selectivity and a much lower detection limit is obtained.
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electrochemical behaviour of sodium Dithionite and sulfite at a gold electrode in alkaline solution
Journal of Electroanalytical Chemistry, 2001Co-Authors: Philippe Westbroek, J De Strycker, K Van Uytfanghe, E. TemmermanAbstract:Abstract The role of the surface condition of a gold electrode in the electrochemical behaviour of sodium Dithionite and sulfite has been studied in alkaline solution. Dithionite is oxidised to sulfate in two steps, with sulfite as the intermediate. Both limiting currents of the corresponding waves obey the Levich equation. Hydroxide ions are consumed in both oxidation steps and when the free hydroxide ion–Dithionite concentration ratio is lower than 8 the second wave, due to the oxidation of Dithionite to sulfate, splits and a new wave appears, shifted by approximately 200 mV in the positive direction. In this wave hydroxide ions released by the dissociation of water are consumed. The oxidation of Dithionite to sulfate becomes inhibited by the formation of Au(III)hydroxide at the electrode surface, while the oxidation of the free hydroxide ions is not inhibited. Hysteresis effects observed between the forward positive and a reverse negative scans can be explained by assuming that the inhibitory effect is eliminated by the formation and subsequent chemisorption of oxygen at the gold electrode surface.
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influence of changes of platinum electrode surface condition on the kinetics of the oxidation of sodium Dithionite and sulfite in alkaline solution
Electrochemistry Communications, 2000Co-Authors: Emmanuel Gasana, Philippe Westbroek, Eduard Temmerman, H. P. Thun, F TwagiramunguAbstract:Abstract The influence of the surface condition of a platinum electrode on the kinetics of the electrochemical oxidation of sodium Dithionite and sulfite was investigated. It was found that the oxidation of sulfite does only occur at platinum oxide while the oxidation of Dithionite takes place at platinum oxide as well as at platinum hydroxide and bare platinum. However, Dithionite cannot be oxidised at rearranged platinum hydroxide, which is formed during the reduction of platinum oxide, a process that is strongly dependent on the applied anodic vertex potential. For both substances a hysteresis effect was observed between forward and backward scan but in both cases the effects could be explained considering the platinum surface condition. As well in the absence as in the present of sulfite and/or Dithionite reproducible current-potential curve were obtained after cycling three times between the applied vertex potentials. The observed difference between the first and subsequent scans again could be explained when the variation of the platinum surface condition as a function of potential and number of cycles was taken into consideration.
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Electrochemical behaviour of sodium Dithionite at a platinum electrode and determination of diffusion coefficient in alkaline solution
Analytical Communications, 1999Co-Authors: Emmanuel Gasana, Philippe Westbroek, Eduard Temmerman, H. P. ThunAbstract:The electrochemical behaviour of sodium Dithionite at a platinum electrode has been investigated in this paper. Two oxidation waves of sodium Dithionite were observed with formation of sulfite as a stable intermediate species. It has been found that the oxidation of sodium Dithionite to sulfite, according to the first wave, is controlled by the rate of mass transport, the oxidation of sulfite to sulfate, however, is not purely controlled by transport phenomena. Using the ratio of the limiting currents of both oxidation waves it was possible to determine the diffusion coefficient of sodium Dithionite by extrapolation to the small rotation rate of the platinum electrode. From the obtained results it is also advisable to make use of the first oxidation reaction for analytical purposes.
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Possibilities to measure the concentration of sodium Dithionite in textile applications by means of amperometric sensors
Autex Research Journal, 1999Co-Authors: Philippe Westbroek, Emmanuel Gasana, Filip Govaert, E. Temmerman, Paul KiekensAbstract:By using linear sweep voltammetry and chronoamperometry at a rotating disc electrode it was found that sodium Dithionite can be oxidised at several electrode materials. At platinum, palladium, glassy carbon and gold an oxidation reaction was observed that showed promising characteristics for analytical purposes and sensor development. The limiting current signal at a potential of +0.3 V vs. SSE is proportional to the concentration of sodium Dithionite, the electrode reacts almost immediately on a change of concentration of sodium Dithionite and experimental proof is given that the electrode is stable for at least 3 days without recalibration. The electrode can be calibrated by a one point calibration because the calibration curve is linear and goes through the origin.
Shihao Chen - One of the best experts on this subject based on the ideXlab platform.
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sodium Dithionite mediated decarboxylative sulfonylation facile access to tertiary sulfones
Angewandte Chemie, 2020Co-Authors: Shihao Chen, Ming Wang, Xuefeng JiangAbstract:A straightforward multicomponent decarboxylative cross coupling of redox-active esters (N-hydroxyphthalimide ester), sodium Dithionite, and electrophiles was established to construct sterically bulky sulfones. The inorganic salt sodium Dithionite not only served as the sulfur dioxide source, but also acted as an efficient radical initiator for the decarboxylation. Notably, diverse naturally abundant carboxylic acids and artificially prepared carboxyl-containing drugs with multiple heteroatoms and sensitive functional groups successfully underwent this decarboxylative sulfonylation to provide sterically bulky tertiary sulfones. Mechanistic studies further demonstrated that decarboxylation was the rate-determining step and occurred via a single-electron transfer (SET) process with the assistance of sodium Dithionite.
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Sodium Dithionite‐Mediated Decarboxylative Sulfonylation: Facile Access to Tertiary Sulfones
Angewandte Chemie (International ed. in English), 2020Co-Authors: Shihao Chen, Ming Wang, Xuefeng JiangAbstract:A straightforward multicomponent decarboxylative cross coupling of redox-active esters (N-hydroxyphthalimide ester), sodium Dithionite, and electrophiles was established to construct sterically bulky sulfones. The inorganic salt sodium Dithionite not only served as the sulfur dioxide source, but also acted as an efficient radical initiator for the decarboxylation. Notably, diverse naturally abundant carboxylic acids and artificially prepared carboxyl-containing drugs with multiple heteroatoms and sensitive functional groups successfully underwent this decarboxylative sulfonylation to provide sterically bulky tertiary sulfones. Mechanistic studies further demonstrated that decarboxylation was the rate-determining step and occurred via a single-electron transfer (SET) process with the assistance of sodium Dithionite.
Gonzalo Vázquez - One of the best experts on this subject based on the ideXlab platform.
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Density and Viscosity of Aqueous Solutions of Sodium Dithionite, Sodium Hydroxide, Sodium Dithionite + Sucrose, and Sodium Dithionite + Sodium Hydroxide + Sucrose from 25 °C to 40 °C
Journal of Chemical & Engineering Data, 1996Co-Authors: Gonzalo Vázquez, Rocío Varela, And Angeles Cancela, Estrella Alvarez, José M. NavazaAbstract:The density and viscosity of aqueous solutions of sodium Dithionite, sodium hydroxide, sodium Dithionite + sucrose, and sodium Dithionite + sodium hydroxide + sucrose were measured at temperatures from (25 to 40) °C. The concentration ranges were (0 to 1.0) mol·dm-3 for sodium Dithionite, (0 to 1.0) mol·dm-3 for sodium hydroxide, and (0 to 171) g·dm-3 for sucrose. The experimental values were correlated with the concentration of sucrose. The maximum deviation was always less than 0.2%.
