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David N Harpp - One of the best experts on this subject based on the ideXlab platform.
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diselenide assisted Sulfuration of dienes
Tetrahedron Letters, 2004Co-Authors: Andrzej Z Rys, Imad A Abuyousef, Yihua Hou, David N HarppAbstract:Abstract Various diselenides assist in the Sulfuration of dienes giving cyclic di- and tetrasulfides as main products. The reaction requires a 2-fold excess of diselenides to be efficient. Catalytic amounts of diselenides result in lower yields. This is likely due to secondary reactions (polymerization, aromatization) occurring during extended reaction times under catalytic conditions. It was verified that the Sulfur-transferring properties of diselenatetrasulfides are virtually identical to those of diselenides combined with Sulfur. Contrary to previous claims, not only the cyclic diselenatetrasulfide but also linear diselenatetrasulfides (RSeS n SeR) transfer Sulfur to dienes. A mechanism is proposed and its implications to the nature of Diatomic Sulfur are discussed.
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sulfenyl chloride chemistry precursors for Diatomic Sulfur transfer
ChemInform, 1995Co-Authors: Imad A Abuyousef, David N HarppAbstract:When triphenylmethanesulfenyl chloride (1) (or its thio homologue 2) are treated with various bicycles, norbornene (5), or bicyclo[2.2.2]octene (6), dithio adducts 7 and 8 were produced in good isolated yields. Final products were obtained via an episulfide intermediate. The stereochemistry of addition has been determined by X-ray analysis. Treatment of thiosulfenyl chloride 2 (or its dithio homologue 3) with other olefins, cyclopentene (10), cyclohexene (11), or 1,4-dioxene (12), leads to the formation of disulfides (13−15 from 2) and trisulfides (16 and 17 from 3) in high isolated yields (ca. 92%). The structures of 7, 8, and 13−17 were established by 1H and 13C NMR and elemental analysis as well as by X-ray determination. When these adducts are warmed with a 1,3-diene 42, they deliver Diatomic Sulfur-trapped derivatives, cyclic di-49 and tetrasulfide adducts 46. A variety of solvents, temperatures, times, and concentrations were employed to optimize the yield of 46 and 49. The tetrasulfide adduct 46 is...
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sulfenyl chloride chemistry Sulfur transfer to double bonds
ChemInform, 1993Co-Authors: Imad A Abuyousef, Rosemary C Hynes, David N HarppAbstract:Abstract When triphenylmethanesulfenyl chloride (1) (or its thio homolog 2) are treated with various bicycles 1,2 addition reactions take place. Final products occur via an episulfide intermediate. The stereochemistry of addition has been determined by x-ray analysis. Finally, evidence has been obtained for the delivery of Diatomic Sulfur, likely via intermediate 3.
A. N. Startsev - One of the best experts on this subject based on the ideXlab platform.
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Diatomic Sulfur a mysterious molecule
Journal of Sulfur Chemistry, 2019Co-Authors: A. N. StartsevAbstract:Diatomic gaseous Sulfur obtained in thermal processes of elemental Sulfur dissociation and hydrogen sulfide decomposition is considered. It is shown that the thermodynamic parameters of this substa...
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the reaction mechanisms of h2s decomposition into hydrogen and Sulfur application of classical and biological thermodynamics
Journal of Thermodynamics and Catalysis, 2017Co-Authors: A. N. StartsevAbstract:Four possible pathways of H2S decomposition into hydrogen and elemental Sulfur are considered. In the thermal reversible process, H2S dissociation results in the formation of Diatomic both hydrogen and Sulfur in the singlet state according to the rule of spin conservation: (i) On the surface of sulfide catalysts, irreversible H2S splitting proceeds at low temperature through the stage of disulfane, H2S2 formation as a key surface intermediate, followed by its decomposition due to release of hydrogen into the gas phase and recombination of the adsorbed singlet Sulfur into cyclooctaSulfur: (ii) On metal catalysts, irreversible H2S decomposition occurs at low temperature through the stage of H2S dissociation into the adsorbed atomic surface species resulted in the formation of both Diatomic reaction products in the ground electronic state -the singlet hydrogen and the triplet Diatomic Sulfur: (iii) The reactions (ii) and (iii) are considered to be realized under the principles of biological thermodynamics, in the absence of catalyst both reactions are thermodynamically prohibited in the gas phase. The mechanism of H2S assimilation by Sulfur bacteria is suggested to occur in the processes of chemosynthesis resulted in the formation of colorless Sulfur globules and activated hydrogen: (iv) Similar to the bacterial process, the hydrogen production from H2S is realized with the efficiency of 99.6% on metal catalysts immersed into the liquid which is capable well-dissolving H2S.
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Low-temperature catalytic decomposition of hydrogen sulfide on metal catalysts under layer of solvent
2016Co-Authors: A. N. Startsev, O. V. Kruglyakova, Yu. A. Chesalov, S. Ph. Ruzankin, E. A. Paukshtis, V. I. Avdeev, A. A. Zhdanov, Yu. I. Molina, L. M. PlyasovaAbstract:When hydrogen sulfide decomposition {2 H2S ↔ 2 H2 + S2(gas)} is carried out in the flow regime at room temperature on metal catalysts placed in a liquid capable of dissolving H2S and Sulfur, the reaction equilibrium can be significantly (up to 100%) shifted to the right yielding the desired product – hydrogen. The process efficiency was demonstrated using aqueous solutions of monoethanolamine (MEA), sodium carbonate, which is widely used in industry for H2S absorption from tail gases, and aqueous hydrazine as examples. IR and Raman spectroscopy data demonstrated that Sulfur obtained in the solutions is in the form of Diatomic molecules. DFT calculations showed that Diatomic Sulfur forms weakly bound coordinative complexes with solvent molecules. Some problems related to Sulfur accumulation and recovery from the solvents are discussed.
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Low Temperature Catalytic Decomposition of Hydrogen Sulfide into Hydrogen and Diatomic Gaseous Sulfur
Topics in Catalysis, 2013Co-Authors: A. N. Startsev, O. V. Kruglyakova, Yu. A. Chesalov, S. Ph. Ruzankin, E. A. Kravtsov, T. V. Larina, E. A. PaukshtisAbstract:A new catalytic reaction of hydrogen sulfide decomposition is discovered, the reaction occurs on metal catalysts in gas phase according to equation $$2{\text{H}}_{2} {\text{S}} \leftrightarrow 2{\text{H}}_{2} + {\text{S}}_{2}^{{({\text{gas}})}}$$ 2 H 2 S ↔ 2 H 2 + S 2 ( gas ) to produce hydrogen and gaseous Diatomic Sulfur, conversion of hydrogen sulfide at room temperature is close to 15 %. The thermodynamic driving force of the reaction is the formation of the chemical Sulfur–Sulfur bond between two hydrogen sulfide molecules adsorbed on two adjacent metal atoms in the key surface intermediate and elimination of hydrogen into gas phase. “Fingerprints” of Diatomic Sulfur adsorbed on the solid surfaces and dissolved in different solvents are studied. In closed vessels in adsorbed or dissolved states, this molecule is stable for a long period of time (weeks). A possible electronic structure of Diatomic gaseous Sulfur in the singlet state is considered. According to DFT/CASSCF calculations, energy of the singlet state of S_2 molecule is over the triplet ground state energy for 10.4/14.4 kcal/mol. Some properties of gaseous Diatomic Sulfur are also investigated. Catalytic solid systems, both bulk and supported on porous carriers, are developed. When hydrogen sulfide is passing through the solid catalyst immersed in liquid solvent which is capable of dissolving Sulfur generated, conversion of hydrogen sulfide at room temperature achieves 100 %, producing hydrogen in gas phase. This gives grounds to consider hydrogen sulfide as inexhaustible potential source of hydrogen—a very valuable chemical reagent and environmentally friendly energy product.
E. A. Paukshtis - One of the best experts on this subject based on the ideXlab platform.
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Low-temperature catalytic decomposition of hydrogen sulfide on metal catalysts under layer of solvent
2016Co-Authors: A. N. Startsev, O. V. Kruglyakova, Yu. A. Chesalov, S. Ph. Ruzankin, E. A. Paukshtis, V. I. Avdeev, A. A. Zhdanov, Yu. I. Molina, L. M. PlyasovaAbstract:When hydrogen sulfide decomposition {2 H2S ↔ 2 H2 + S2(gas)} is carried out in the flow regime at room temperature on metal catalysts placed in a liquid capable of dissolving H2S and Sulfur, the reaction equilibrium can be significantly (up to 100%) shifted to the right yielding the desired product – hydrogen. The process efficiency was demonstrated using aqueous solutions of monoethanolamine (MEA), sodium carbonate, which is widely used in industry for H2S absorption from tail gases, and aqueous hydrazine as examples. IR and Raman spectroscopy data demonstrated that Sulfur obtained in the solutions is in the form of Diatomic molecules. DFT calculations showed that Diatomic Sulfur forms weakly bound coordinative complexes with solvent molecules. Some problems related to Sulfur accumulation and recovery from the solvents are discussed.
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Low Temperature Catalytic Decomposition of Hydrogen Sulfide into Hydrogen and Diatomic Gaseous Sulfur
Topics in Catalysis, 2013Co-Authors: A. N. Startsev, O. V. Kruglyakova, Yu. A. Chesalov, S. Ph. Ruzankin, E. A. Kravtsov, T. V. Larina, E. A. PaukshtisAbstract:A new catalytic reaction of hydrogen sulfide decomposition is discovered, the reaction occurs on metal catalysts in gas phase according to equation $$2{\text{H}}_{2} {\text{S}} \leftrightarrow 2{\text{H}}_{2} + {\text{S}}_{2}^{{({\text{gas}})}}$$ 2 H 2 S ↔ 2 H 2 + S 2 ( gas ) to produce hydrogen and gaseous Diatomic Sulfur, conversion of hydrogen sulfide at room temperature is close to 15 %. The thermodynamic driving force of the reaction is the formation of the chemical Sulfur–Sulfur bond between two hydrogen sulfide molecules adsorbed on two adjacent metal atoms in the key surface intermediate and elimination of hydrogen into gas phase. “Fingerprints” of Diatomic Sulfur adsorbed on the solid surfaces and dissolved in different solvents are studied. In closed vessels in adsorbed or dissolved states, this molecule is stable for a long period of time (weeks). A possible electronic structure of Diatomic gaseous Sulfur in the singlet state is considered. According to DFT/CASSCF calculations, energy of the singlet state of S_2 molecule is over the triplet ground state energy for 10.4/14.4 kcal/mol. Some properties of gaseous Diatomic Sulfur are also investigated. Catalytic solid systems, both bulk and supported on porous carriers, are developed. When hydrogen sulfide is passing through the solid catalyst immersed in liquid solvent which is capable of dissolving Sulfur generated, conversion of hydrogen sulfide at room temperature achieves 100 %, producing hydrogen in gas phase. This gives grounds to consider hydrogen sulfide as inexhaustible potential source of hydrogen—a very valuable chemical reagent and environmentally friendly energy product.
Imad A Abuyousef - One of the best experts on this subject based on the ideXlab platform.
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diselenide assisted Sulfuration of dienes
Tetrahedron Letters, 2004Co-Authors: Andrzej Z Rys, Imad A Abuyousef, Yihua Hou, David N HarppAbstract:Abstract Various diselenides assist in the Sulfuration of dienes giving cyclic di- and tetrasulfides as main products. The reaction requires a 2-fold excess of diselenides to be efficient. Catalytic amounts of diselenides result in lower yields. This is likely due to secondary reactions (polymerization, aromatization) occurring during extended reaction times under catalytic conditions. It was verified that the Sulfur-transferring properties of diselenatetrasulfides are virtually identical to those of diselenides combined with Sulfur. Contrary to previous claims, not only the cyclic diselenatetrasulfide but also linear diselenatetrasulfides (RSeS n SeR) transfer Sulfur to dienes. A mechanism is proposed and its implications to the nature of Diatomic Sulfur are discussed.
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sulfenyl chloride chemistry precursors for Diatomic Sulfur transfer
ChemInform, 1995Co-Authors: Imad A Abuyousef, David N HarppAbstract:When triphenylmethanesulfenyl chloride (1) (or its thio homologue 2) are treated with various bicycles, norbornene (5), or bicyclo[2.2.2]octene (6), dithio adducts 7 and 8 were produced in good isolated yields. Final products were obtained via an episulfide intermediate. The stereochemistry of addition has been determined by X-ray analysis. Treatment of thiosulfenyl chloride 2 (or its dithio homologue 3) with other olefins, cyclopentene (10), cyclohexene (11), or 1,4-dioxene (12), leads to the formation of disulfides (13−15 from 2) and trisulfides (16 and 17 from 3) in high isolated yields (ca. 92%). The structures of 7, 8, and 13−17 were established by 1H and 13C NMR and elemental analysis as well as by X-ray determination. When these adducts are warmed with a 1,3-diene 42, they deliver Diatomic Sulfur-trapped derivatives, cyclic di-49 and tetrasulfide adducts 46. A variety of solvents, temperatures, times, and concentrations were employed to optimize the yield of 46 and 49. The tetrasulfide adduct 46 is...
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sulfenyl chloride chemistry Sulfur transfer to double bonds
ChemInform, 1993Co-Authors: Imad A Abuyousef, Rosemary C Hynes, David N HarppAbstract:Abstract When triphenylmethanesulfenyl chloride (1) (or its thio homolog 2) are treated with various bicycles 1,2 addition reactions take place. Final products occur via an episulfide intermediate. The stereochemistry of addition has been determined by x-ray analysis. Finally, evidence has been obtained for the delivery of Diatomic Sulfur, likely via intermediate 3.
O. V. Kruglyakova - One of the best experts on this subject based on the ideXlab platform.
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Low-temperature catalytic decomposition of hydrogen sulfide on metal catalysts under layer of solvent
2016Co-Authors: A. N. Startsev, O. V. Kruglyakova, Yu. A. Chesalov, S. Ph. Ruzankin, E. A. Paukshtis, V. I. Avdeev, A. A. Zhdanov, Yu. I. Molina, L. M. PlyasovaAbstract:When hydrogen sulfide decomposition {2 H2S ↔ 2 H2 + S2(gas)} is carried out in the flow regime at room temperature on metal catalysts placed in a liquid capable of dissolving H2S and Sulfur, the reaction equilibrium can be significantly (up to 100%) shifted to the right yielding the desired product – hydrogen. The process efficiency was demonstrated using aqueous solutions of monoethanolamine (MEA), sodium carbonate, which is widely used in industry for H2S absorption from tail gases, and aqueous hydrazine as examples. IR and Raman spectroscopy data demonstrated that Sulfur obtained in the solutions is in the form of Diatomic molecules. DFT calculations showed that Diatomic Sulfur forms weakly bound coordinative complexes with solvent molecules. Some problems related to Sulfur accumulation and recovery from the solvents are discussed.
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Low Temperature Catalytic Decomposition of Hydrogen Sulfide into Hydrogen and Diatomic Gaseous Sulfur
Topics in Catalysis, 2013Co-Authors: A. N. Startsev, O. V. Kruglyakova, Yu. A. Chesalov, S. Ph. Ruzankin, E. A. Kravtsov, T. V. Larina, E. A. PaukshtisAbstract:A new catalytic reaction of hydrogen sulfide decomposition is discovered, the reaction occurs on metal catalysts in gas phase according to equation $$2{\text{H}}_{2} {\text{S}} \leftrightarrow 2{\text{H}}_{2} + {\text{S}}_{2}^{{({\text{gas}})}}$$ 2 H 2 S ↔ 2 H 2 + S 2 ( gas ) to produce hydrogen and gaseous Diatomic Sulfur, conversion of hydrogen sulfide at room temperature is close to 15 %. The thermodynamic driving force of the reaction is the formation of the chemical Sulfur–Sulfur bond between two hydrogen sulfide molecules adsorbed on two adjacent metal atoms in the key surface intermediate and elimination of hydrogen into gas phase. “Fingerprints” of Diatomic Sulfur adsorbed on the solid surfaces and dissolved in different solvents are studied. In closed vessels in adsorbed or dissolved states, this molecule is stable for a long period of time (weeks). A possible electronic structure of Diatomic gaseous Sulfur in the singlet state is considered. According to DFT/CASSCF calculations, energy of the singlet state of S_2 molecule is over the triplet ground state energy for 10.4/14.4 kcal/mol. Some properties of gaseous Diatomic Sulfur are also investigated. Catalytic solid systems, both bulk and supported on porous carriers, are developed. When hydrogen sulfide is passing through the solid catalyst immersed in liquid solvent which is capable of dissolving Sulfur generated, conversion of hydrogen sulfide at room temperature achieves 100 %, producing hydrogen in gas phase. This gives grounds to consider hydrogen sulfide as inexhaustible potential source of hydrogen—a very valuable chemical reagent and environmentally friendly energy product.