Showing papers on "Sodium sulfide published in 2005"

Method for manufacturing chalcopyrite thin-film solar cell

Abstract: Disclosed is a method for manufacturing a chalcopyrite thin-film solar cell wherein adhesion between an electrode layer and a light absorption layer composed of a chalcopyrite compound is good, and the multilayer structure is stable even when the concentration of an alkali metal-containing liquid constituting an alkali layer is relatively high and no problem is caused in appearance. This method comprises a first step wherein a precursor is formed by forming an In metal layer and a Cu-Ga alloy layer on an Mo electrode layer (2) by a sputtering process, a second step wherein an alkali metal-containing liquid is applied to the precursor, a selenization step wherein a substrate (1) which has gone through the first and second steps is selenized, and a transparent electrode forming step wherein a light-transmitting conductive layer is formed as a film. As the alkali metal-containing liquid, there is used an aqueous solution of an alkali metal compound such as sodium tetraborate, sodium sulfide or sodium aluminum sulfate.

Liquid‐Liquid‐Liquid Phase Transfer Catalysis: A Novel and Green Concept for Selective Reduction of Substituted Nitroaromatics

Abstract: The selective reduction of nitroaromatics to the corresponding amines is an important transformation since many aromatic amines exhibit biological activities and find a multitude of industrial applications, being intermediates for the synthesis of dyes, pharmaceuticals and agrochemicals. A variety of nitroaromatics dissolved in organic solvents was reduced by using aqueous sodium sulfide, and tetrabutylammonium bromide (TBAB) as the phase transfer catalyst by choosing appropriate concentrations which resulted in three immiscible liquid phases. Compared to L-L PTC, the L-L-L PTC offers much higher rates of reaction, better selectivities and repeated use of catalyst. The selectivities for the desired products were 100%.

Kinetics of the reaction between dissolved sodium sulfide and biologically produced sulfur

Abstract: The kinetics of the heterogeneous reaction between dissolved sodium sulfide and biologically produced sulfur particles has been studied by measuring the formation of polysulfide ions, Sx2-, in time (pH = 8.0, T = 30-50 °C). Detailed knowledge of this reaction is essential to understand its effect on a biotechnological hydrogen sulfide removal process. The data were fitted with a reaction rate model in which heterogeneous reaction kinetics, decreasing particle size, and a nonuniform particle size distribution were incorporated. Polysulfide ions formed in this reaction have an autocatalytic effect. The observed reaction rate of the autocatalyzed reaction is limited by chemical reaction, contrary to earlier reports for the reaction of sulfide with "inorganic" granular sulfur, which was diffusion-rate-limited. The small particle size or the specific hydrophilic surface properties probably make the surface of the biologically produced sulfur particles more easily available for reaction than the surface of granular sulfur.

Lignin polymers and composites

Abstract: This chapter focuses on lignin-based bioproducts. Lignin is found as a cell wall component in all vascular plants and in the woody stems of arborescent angiosperms and gymnosperms. Delignification, the process of extracting lignin from plant sources, can be done using a variety of chemical and solvent methods. Industrially, the two most widely used methods of delignification are sulfite and alkaline or kraft pulping. Kraft lignin is obtained by treatment of lignocellulosic materials with kraft pulping liquor, which contains mainly sodium hydroxide and sodium sulfide, with other sodium salts as minor components. Chemical modification of lignin is another area of significant scientific work. It is largely based on the knowledge of lignin modifications used to dissolve lignin in organic solvents and applied in the determination of lignin functional groups. Chemical modifications of lignins include acetylation, esterification, etherification, sulfonation, sulfomethylation, amination, halogenation, and nitration. Properties and applications of chemically modified lignins in polymers are discussed in the chapter.

[5C + 1S] annulation: a facile and efficient synthetic route toward functionalized 2,3-dihydrothiopyran-4-ones.

Abstract: A facile and efficient synthetic route toward highly substituted 2,3-dihydrothiopyran-4-ones 2 has been developed via a formal [5C + 1S] annulation of readily available α-alkenoyl ketene-(S,S)-acetals 1 with sodium sulfide nonahydrated salt (Na2S·9H2O) and utilized in the synthesis of 2-(4-chlorophenyl)-6-(morpholin-4-yl)-4H-thiopyran-4-one 5l, an inhibitor of DNA-dependent protein kinase (DNA-PK).

Na5(In4S)(InS4)3.6H2O, a zeolite-like structure with unusual SIn4 tetrahedra.

Abstract: A hydrated sodium indium sulfide, Na5(In4S)(InS4)3·6H2O, has been prepared by hydrothermal synthesis. This material contains a tetrahedral sulfur site coordinated to four trivalent indium ions, an unusual bonding pattern not previously observed in open framework chalcogenides. The structure is related to the perovskite (CaTiO3) type with simultaneous substitutions of Ti by SIn4, O by InS4, and Ca2+ by [Na5(H2O)6]5+. It is a wide-gap semiconductor and shows photocatalytic activity under UV light for hydrogen generation from aqueous solution without use of any cocatalyst.

Efficient oxidation of sulfides with sodium periodate catalyzed by manganese(III) Schiff base complexes

Abstract: Efficient oxidation of sulfides was achieved. In the chemical system containing Mn(III)–salophen complex as catalyst, sulfides converted efficiently to the corresponding sulfoxides and sulfones with sodium periodate. The ability of various Schiff base complexes in the oxidation of sulfides was also investigated.

Effects of hydrogen sulfide to Vibrio fischeri, Scenedesmus vacuolatus, and Daphnia magna

Abstract: The effects of hydrogen sulfide (H2S) were tested in three ecotoxicological tests in order to evaluate its confounding potential in assessment of pore water and groundwater toxicity. The luminescent bacteria Vibrio fischeri, the water flea Daphnia magna, and the microalgae Scenedesmus vacuolatus often are part of a biotest battery. A new technique for the synthesis of hydrogen sulfide solutions of defined concentrations using an electrochemical generator instead of sodium sulfide solutions was used. Because hydrogen sulfide is volatile, the loss rate of H2S was studied over time to enable estimation of the mean test concentrations over the whole test duration. Loss rates were calculated to be 13 +/- 6% after 30 min, and 39 +/- 11% and 43 +/- 16% after a 24- and 48-h exposure time, respectively. Sensitivities of the test organisms in terms of median effective concentration (EC50), corrected for the above loss rates, varied from 0.28 to 0.0036 and 0.055 mM for the luminescent bacteria, the crustacea, and the algae, respectively. A species-sensitivity distribution using EC and mean lethal concentration literature data for marine and freshwater crustaceans and phytoplankton showed a medium sensitivity of the water flea D. magna, though the bacteria V. fischeri and the algae S. vacuolatus were among the least-sensitive group of organisms. This demonstrates that only the algae and the bacteria are easy to use in the assessment of toxicity of matrices with H2S concentrations above 0.06 mM.

Reactions of benzene oxide with thiols including glutathione

Abstract: S-Phenylmercapturic acid is a minor metabolite of benzene used as a biomarker for human benzene exposures The reaction of intracellular glutathione with benzene oxide-oxepin, the initial metabolite of benzene, is presumed to give 1-(S-glutathionyl)-cyclohexa-3,5-dien-2-ol, which undergoes dehydration to S-phenylglutathione, the precursor of S-phenylmercapturic acid To validate the proposed route to S-phenylglutathione, reactions of benzene oxide-oxepin with glutathione and other sulfur nucleophiles have been studied The reaction of benzene oxide with an excess of aqueous sodium sulfide, followed by acetylation, gave bis-(6-trans-5-acetoxycyclohexa-1,3-dienyl)sulfide, the structure of which was proved by X-ray crystallography Reactions of benzene oxide-oxepin in a 95:5 (v/v) mixture of phosphate buffer in D2O with (CD3)2SO were monitored by 1H NMR spectroscopy In the absence of glutathione, the half-life of benzene oxide-oxepin was ca 34 min at 25 degrees C and pD 70 The half-life was not affected in the range of 2-15 mM glutathione in the presence and absence of a commercial sample of human glutathione S-transferase (at pH 70, 80, 85, or 100) The adduct 1-(S-glutathionyl)-cyclohexa-3,5-diene-2-ol was identified in these reaction mixtures, especially at higher pH, by mass spectrometry and by its acid-catalyzed decomposition to S-phenylglutathione Incubation of benzene oxide with N-acetyl-L-cysteine at 37 degrees C and pH 100 and subsequent mass spectrometric analysis of the mixture showed formation of pre-S-phenylmercapturic acid and the dehydration product, S-phenylmercapturic acid The data validate the premise that benzene oxide-oxepin can be captured by glutathione to give (1R,2R)- and/or (1S,2S)-1-(S-glutathionyl)-cyclohexa-3,5-dien-2-ol, which dehydrate to S-phenylglutathione The capture is a relatively inefficient process at pH 7 that is accelerated at higher pH These studies account for the observation that the metabolism of benzene is dominated by the formation of phenol The pathway leading to S-phenylmercapturic acid is necessarily minor on account of the low efficiency of benzene oxide capture by glutathione at pH 7 vs spontaneous rearrangement to phenol

Desulfurization of petroleum streams using metallic sodium

Abstract: The invention is a method of removing sulfur from a hydrocarbon feed using the steps of dissolving metallic sodium in a solvent and combining the sodium/solvent solution with a liquid hydrocarbon feed containing an organosulfur species. The pressure of combination is above the vapor pressure of the solvent. The combined hydrocarbon feed and solvent solution are placed in a low pressure environment to vaporize the solvent. The resulting stream is combined with hydrogen gas and this stream is heated and pressurized to form a liquid hydrocarbon product containing sodium sulfide. This product is then cooled, and the sodium sulfide is extracted.

Synthesis and characterization of poly(p-phenylene sulfide sulfone/ketone) copolymer

Abstract: High molecular weight poly(phenylene sulfide sulfone/phenylene sulfide ketone) copolymer was synthesized by the step polycondensation of sodium sulfide (Na2S·xH2O) with 4,4′-dichlorobenosulfone (DCDPS), 4,4′-difldibenzophenone (DFBP) between 180∼202 °C at normal pressure. The copolymer was characterized by FT-IR spectrum, UV spectrum, 1H-NMR spectrum, X-ray diffraction and small angle light scattering (SALS), DSC and TGA. The more ketone in the copolymer chain, the better thermal properties of the PPSS/Ks resins have. The copolymer was found to be amorphous but has little local ordering structures with the content of ketone in the range of 0∼45% which is different from other high pressure polymerization.

A study on nickel hydroxide crystallization characteristics

Abstract: The precipitation characteristics of nickel hydroxide as well as carbonate and sulfide were studied to determine the proper treatment condition of the wastewater induced from nickel-plating industry. When the pH value was maintained higher than 10, the nickel concentrations in the effluent could be kept lower than 5 mg/l. The precipitation of nickel salts in the model wastewater was conducted by alkaline addition, such as the uses of sodium hydroxide, sodium carbonate, sodium bicarbonate and sodium sulfide. In case of sulfide treatment, the nickel concentration of treated wastewater showed the lowest value after the removal of precipitates. The change of particle size of the crystal precipitates by the precipitation conditions and precipitants was also investigated. In spite of the various precipitation conditions that were adopted, the change of particle size of the crystal precipitates showed no great differences. The settling rates of the precipitated particles were observed and the free settling period was terminated within 20 minutes. Although the hindered settling as well as bed compaction progressed subsequently, the bed heights were maintained almost the same level after few hours later

Silicate Enhanced Enzymatic Dehairing: A New Lime-Sulfide-Free Process for Cowhides

Abstract: A conventional dehairing process with sodium sulfide and lime is a major source of the pollution from the tanning industry. In other words, conventional dehairing processes degrade the hair to the extent that it cannot be recovered; thus, these processes become a major contributor to wastewater pollution. In this study, an attempt has been made to develop a lime and sulfide-free dehairing process using a commercial enzyme formulation with the activation of a silicate salt. A dip and pile method of application has been standardized. The amount of enzyme and sodium metasilicate has also been optimized based on complete removal of hair. Enhancement of enzyme activity by the addition of silicate has been demonstrated through activity measurements. Hair removal is found to be complete using scanning electron microscope analysis. Strength and bulk properties of the experimental leathers are comparable to that of control leathers. The process enjoys a significant reduction in chemical oxygen demand (COD) and total solids (TS) by 53 and 26%, respectively. More importantly, the application of enzyme for dehairing results in an 8% area increase in the final leather. Also, the process is proven to be techno-economically feasible.

Preparation of sulfide chain-bearing organosilicon compounds

Abstract: By premixing a sulfide chain-bearing organosilicon compound, a halogenoalkyl group-bearing organosilicon compound, and optionally, sulfur, adding anhydrous sodium sulfide Na2S to the premix, and allowing reaction to take place, a sulfide chain-bearing organosilicon compound having a shorter sulfide chain can be prepared in high yields and at a lost cost while minimizing formation of monosulfide-bearing organosilicon compound.

Sodium sulfide leaching of low-grade jamesonite concentrate in production of sodium pyroantimoniate

Abstract: Sodium sulfide leaching of a low-grade jamesonite concentrate in the production of sodium pyroantimoniate through the air oxidation process and the influencing factors on the leaching rate of antimony were investigated In order to decrease the consumption of sodium sulfide and increase the concentration of antimony in the leaching solution, two-stage leaching of jamesonite concentrate and combination leaching of high-grade stibnite concentrate and jamesonite concentrate were used The experimental results show that the consumptions of sodium sulfide for the two-stage leaching process and the combination leaching process are decreased by 20% and 60% compared to those of one-stage leaching process respectively The final concentrations of antimony in the leaching solutions of both processes are above 100 g/L

Method for recovering nickel and cobalt

Abstract: PURPOSE:To preferentially precipitate and recover Ni and Co at high yields by adding an alkali sulfide compd to an acid soln obtd by leaching Ni- and Co-contg raw materials with a mineral acid to precipitate and form the Ni and Co as sulfides CONSTITUTION:The ore oxide, waste media and other raw materials in which the Ni and Co coexist are treated with the mineral acids, such as sulfuric acid, hydrochloric acid and nitric acid, to prepare an acid aq soln of pH >15 in which the Ni and Co or further, simultaneously contained components, such as Fe, Al, Mn, Mg and Cr, are acid-leached After this aq acid soln is heated to and held at <=100 degC, the alkali sulfide compd, such as sodium sulfide or sodium hydrosulfide, is added thereto at 11 to 13 times the theoretical equiv for formation of NiS and CoS to effect reaction for 5 to 60 minutes The Ni and Co are preferentially deposited and precipitated as NiS and CoS and are filtered The Ni and Co are thus recovered in the form of the sulfides at the good yields

Surface modification of cvd polymer films

Abstract: The present invention relates to a method for forming a conformal coating having a reactive surface. In the method, an ultrathin layer composed of a polymer having repeating units derived from unsubstituted p-xylylene, substituted p-xylylene, phenylene vinylene, phenylene ethynylene, 1,4-methylene naphthalene, 2,6-methylene naphthalene, 1,4-vinylene naphthalene, 2,6-vinylene naphthalene, 1,4-ethynylene naphthalene, 2,6-ethynylene naphthalene, combinations thereof, precursors therefor or combinations of precursors therefor, is deposited on a substrate by a thermal CVD process. The ultrathin layer is optionally exposed to a source of oxygen and then exposed to a reagent selected from ammonium hydroxide, tetramethylammonium hydroxide, ammonium sulfide, dimethyl sulfide, thioacetic acid, sodium hydrosulfide, sodium sulfide, hydrazine, acetamide and combinations thereof. The surface may be modified readily after the treatment.

Polysulfide Reagent in Solid-Phase Synthesis of Phosphorothioate Oligonucleotides: Greater than 99.8% Sulfurization Efficiency

Abstract: A solution of sulfur (0.1 M) and sodium sulfide (0.01M) in 3-picoline, referred to as polysulfide reagent, rapidly converts trialkyl and triaryl phosphite triesters to the corresponding phosphorothioate derivatives. Greater than 99.8% average stepwise sulfurization efficiency is obtained in the solid-phase synthesis of DNA and RNA phosphorothioate olgonucleotides via the phosphoramidite approach.

Sulphidization flotation for recovery of lead and zinc from oxide-sulfide ores

Abstract: A new flowsheet was developed to recover the valuable minerals from oxide or oxide-sulfide ores of lead and zinc. The flowsheet consisted of flotation of sulfide minerals, desliming and sulphidization-flotation of oxide minerals. The corresponding reagent system and techniques to the flowsheet were investigated. Batch and continuous tests show that the dosage of sodium sulfide, temperature, and collector type are main affecting factors on the recovery of smithsonite and cerussite. For the flotation of cerussite, there is an appropriate dosage of sodium sulfide at which the recovery reaches its maximum value. The required sodium sulfide for smithsonite flotation is higher than that for cerussite and the recovery of smithsonite flotation increases with the dosage of sodium sulfide at low level and becomes insensitive at high dosage. The appropriate temperature for smithsonite and cerussite flotation is found to be 25 - 40 ℃. Amines are found to be the effective collectors for the flotation of smithsonite after sulphidization. Investigation also shows that desliming prior to sulphidization-flotation is essential to the effective recovery of smithsonite and cerussite, and the desliming process of two-stage hydrocyclon is well feasible and effective for the treatment of lead-zinc oxide ores. A further treatment on the cerussite flotation concentrate by shaking table is proposed to obtain higher lead grade.

Heterocycles with a Bridging Nitrogen Atom. 17. Unexpected Formation of Indolizine during the Preparation of (2-Thioxopyridin-1-yl) Acetate

Abstract: Ethyl 2-hydroxy-1-(2-thioxopyridin-1(2H)-yl)indolizin-3-carboxylate was formed along with ethyl (2-thioxopyridin-1(2H)-acetate from the reaction of 2-bromo-1-(ethoxycarbonylmethyl)pyridinium bromide with sodium sulfide. The structures of all compounds were confirmed by X-ray crystallography.

Effect of pulp potential on the flotation of a sulfide copper ore

Abstract: Surface oxidation of secondary minerals, such as chalcocite, bornite and digenite, present in the Salobo copper ore makes their flotation difficult and requires excessive reagent consumptions. Two possibilities for reducing the collector and fr other additions were investigated. These were sulfidization of the pulp prior toflotation and using nitrogen to replace air in flotation. Sulfidization requires pulp potential control to keep this parameter in the range of 0 to +100 mV, yielding high copper recoveries at minimum collector (90 git) and fr other (60 git) dosages. Flotation with nitrogen reduces the sodium sulfide dosages required to keep the pulp potential within the optimum range.

Separation and Enrichment of Valuable Elements from Copper Residue Leached by Chlorine

Abstract: The separation and enrichment of valuable elements in copper residue slag leached by chlorine in Jinchuan company were studied by the method of sodium sulfide leaching and SO_2 neutralization. The effect of temperature, concentration of Na_2S, molar ratio of Na_2S to S~0 and leaching time on leaching process were researched. The experimental results show that the average residue ratio is (26.52%) and the leaching ratio of noble metals is 10.63% when the temperature is 25 ℃, concentration of Na_2S is 0.5 mol/L, n(Na_2S)/n(S~0)=1∶4 and the leaching time is (60 min.) And the content of noble metals is enriched 3.96 times in the leached residue. The element sulphur deposits from solution by bubbling SO_2 into solution. The quality of element sulphur may reach 99.08% and the recycle ratio of sulphur is 54.6%74.19%.

Selective Separation of Cu, Zn and Ni by Sulfuration of Electroplating Wastewater

Abstract: Selective recovery of copper, zinc and nickel from electroplating wastewater was studied by precipitating the metal sulfides formed by sulfuration treatment. CuSO4, ZnSO4 and NiSO4 involved in model solutions and those of plating wastewater were adjusted to 100-120mg dm−3 of the initial metal concentration. Two kinds of sulfurating agents, sodium sulfide (Na2S) and sodium hydrosulfide (NaHS) of 6.8×10−2 mol dm−3, were employed.As a result, it was found that Na2S was more effective for the separation of the metal sulfides precipitated. The formation of metal sulfides was dependent on the pH value of the solution. In the sulfuration process using Na2S, copper was first separated from the solution as copper sulfide in pH1.4-1.5, followed by the formation of zinc sulfide in pH2.4-2.5. Subsequently, nickel sulfide was precipitated after the formation of copper and zinc sulfides in the residual solution in pH5.5-6.0.The same results of the formation behavior of copper sulfide, zinc sulfide and nickel sulfide in a simulated plating solution were obtained for those in an electroplating solution.

Method for treating sawage generated by preparing carbide slag

Abstract: A process for treating the sewage generated by preparing acetylene from calcium carbide includs such steps as adding the solution of the Fe salt, Zn salt and Cu salt to the sewage to make the pollutants become metal compounds, depositing, acid hydrolyzing to generate H2S gas and the solution of Fe salt, En salt and Cu salt, spraying NaOH solution to absorb H2S and generate sodium sulfide (or hydrosulfide), and reusing said solution to treat sewage.

IVB family compound of schiff base containing olefine oxo and its use in ethylene polymerization

Abstract: A IV B-family match of Schiff base containing oxyl, which can be used as catalyst for polymerizing ethene, is prepared through p-nitrophenyloxyether, reducing it by sodium sulfide and sulfur to become vinoxy phenylamine, reacting on alkyl substituted salicylaldehyde in absolute alcohol under catalysis of molecular sieve to obtain Schiff base ligand, reacting on n-butyl lithium to obtain salt, and reacting on the halide of transition metal in IVB family. It has high catalyti activity.