Showing papers on "Sodium sulfide published in 1991"

Mechanism of poly(p-phenylene sulfide) growth from p-dichlorobenzene and sodium sulfide

Abstract: The chemistry of poly(p-phenylene sulfide) (PPS) growth from Na 2 S and p-dichlorobenzene in NMP is dominated by the ionic S N Ar mechanism. Consistent with this mechanism are model reactions that obey discrete second-order reaction kinetics in both independent and competition experiments. Reaction rates are as well affected by substituents in a fashion predicted by the S N Ar mechanism. Diagnostic reactions to probe radical mechanisms provide no evidence for radical intermediates with the possible exception of certain anomalous side reactions

Fermi-level movement at GaAs(001) surfaces passivated with sodium sulfide solutions

Abstract: Reflectance anisotropy spectrometry is used to study the electronic properties of sulfide‐passivated GaAs. The optical technique allows measurement of the Fermi‐level displacement at the surface in situ, while the sample is immersed into a sulfide solution. The kinetics of the process was found to be very sensitive to conductivity type and doping level in GaAs.

N-[1-(Benzotriazol-1-yl)alkyl]amides, Versatile Amidoalkylation Reagents. Part 3.1 Syntheses of Open-Chain N-Protected-Hemithioaminals

Abstract: N-[(1-Benzotriazol-1-yl)alkyl]amides 1 react readily with a variety of thiols (both aliphatic and aromatic) and sodium sulfide under mild conditions to give N-acylhemithioaminals in good yields

Hydrogen Gas Production by an Ectothiorhodospira vacuolata Strain

Abstract: A hydrogen gas (H(2))-producing strain of Ectothiorhodospira vacuolata isolated from Soap Lake, Washington, possessed nitrogenase activity. Increasing evolution of H(2) with decreasing ammonium chloride concentrations provided evidence that nitrogenase was the catalyst in gas production. Cells were grown in a mineral medium plus 0.2% acetate with sodium sulfide as an electron donor. Factors increasing H(2) production included addition of reduced carbon compounds such as propionate and succinate, increased reducing power by increasing sodium sulfide concentrations, and increased energy charge (ATP) by increasing light intensity.

Stress Corrosion Cracking Behavior of 90/10 Cu-Ni Alloy in Sodium Sulfide Solutions

Abstract: The stress corrosion cracking (SCC) of 90/10 Cu-Ni alloy in sulfide solutions is not reported in the literature. The SCC behavior of the alloy was studied in dilute and concentrated Na2S s...

Production of high-molecular weight polyphenylene sulfide

Abstract: PURPOSE:To obtain the subject moderately branched polyphenylene sulfide by mixing an alkali metal sulfide with a dihalobenzene and a specific aromatic compound in the presence of an organic amide solvent, followed by reaction under heating. CONSTITUTION:In the presence of an organic amide solvent such as N,N- dimethylacetamide, (A) an alkali metal sulfide such as sodium sulfide is mixed with (B) a dihalobenzene such as p-dichlorobenzene and (C) an aromatic compound of the formula (Ar is 3-20C aromatic group; X is halogen; Y is H or alkali metal; (m) is 0-2; (n) is 1-6; (m+n)>=3), e.g. 2,3-dichlorothiophenol followed by reaction under heating, thus obtaining the objective polyphenylene sulfide.

Method for treating chelant solutions to remove metals in solution

Abstract: A process for removing at least a portion of any iron, copper, nickel and chromium ions that are chelated by a alkylenepolyamine polyacetic acid or salt in an aqueous liquid waste. The process comprises the steps of (a) adjusting the pH of the liquid to above about 10; (b) adding sufficient sodium sulfide to react with at least a portion of the copper ions; (c) separating precipitated iron and copper compounds; (d) adding nitric acid to adjust the pH to the range of about 6 to 8; (e) adding sufficient sodium nitrite to the liquid to react with at least a portion of the nickel and chromium present; (f) heating the liquid to above about 575° F. for at least about 15 minutes to facilitate precipitation of nickel and chromium; and (g) separating precipitated solids to leave a non-hazardous filtrate.

Catalytic Spectrophotometric Determination of an Ultra-Trace Amount of Lead by Reduction of Resazurin by Sodium Sulfide

Abstract: A Kinetic spectrophotometric method for the determination of ultra-trace amounts of lead(II) is described. This method is based on the catalytic action of this ion on the reduction of resazurin by sulfide. The course of the chemical reaction is followed spectrophotometrically by the measurement of reduction in absorbance of resazurin at 605 nm. The calibration range of Pb(II) is dependent on the sulfide concentration. With this method 1 ng m1−1 lead can be detected. The method is used for determination of Pb(II) in KNO3 (Fluka) and in water.

Spectrophotometric determination of trace amounts of selenium based on catalytic reduction of toluidine blue by sulfide ion

Abstract: A simple, rapid, and sensitive kinetic method for the determination of trace selenium (0.03–1.5 μg cm−3) based on its catalytic effect on the reduction reaction of toluidine blue and sodium sulfide is reported. The reaction is monitored spectrophotometrically by measuring the decreasing absorbance of toluidine blue at 605 nm by the variable time method. The detection limit is 8 ng cm−3 and the relative standard deviation for 1 μg cm−3 selenium is 1.4%. The procedure was successfully applied to the determination of selenium in real samples.

Method for removing mercury in gas containing unsaturated hydrocarbon

Abstract: PURPOSE:To provide a method for removing mercury from unsatd. hydrocarbon- contg. gas incorporating mercury such as condensate decomposition gas. CONSTITUTION:Unsatd. hydrocarbon-contg. gas is brought into contact with a reacting agent consisting of the aq. soln. of multiple sulfide compd. expressed by MM'Sx (M and M' are sodium or potassium and may be the same or different and (x) is 2-9). By this method, mercury in the unsatd. hydrocarbon-contg. gas is removed as mercury sulfide., When the mixture soln. of multiple sulfide with sodium sulfide is used as a reacting agent, mercury can be dissolved to a high concn. Since this method can be operated at a normal temp., polymn. of olefilns can be relaxed and the influence of the decomposed gas containing unsated. hydrocarbon is suppressed.

The effect of sodium sulfide on the equilibrium of the kraft causticization reaction

Abstract: On a cherche a etendre un modele thermodynamique precedemment developpe pour qu'il inclue les effets du taux de Na 2 S. On a realise 58 essais de basification avec des taux de 0%, 15% et 30%. On a cherche egalement a determiner le parametre de Pitzer decrivant les interactions du sodium avec les ions bisulfure.

Production of halogenothiophenol

Abstract: PURPOSE: To readily produce a mono- or di-halogenothiophenol by reacting a monohalogenophenylthioglycolic acid or a dihalogenophenylthioglycolic acid respectively industrially readily available or producible with a sulfide. CONSTITUTION: A halogenophenylthioglycolic acid (e.g. 2,5- dichlorophenylthioglycolic acid) of formula I [X is Cl or Br. (m) is 1 or 2] is reacted with a sulfide (e.g. sodium sulfide, sodium hydrosulfide or thiophenol) in the presence of a base such as NaOH in a solvent (preferably water as the solvent) to obtain a halogenothiophenol (e.g. 2,5-dichlorthiophenol) of formula II. Mono- and di-halogenothiophenols are useful as an intermediate for synthesis of a medicine, an agricultural chemical, a functional material, etc. COPYRIGHT: (C)1993,JPO&Japio

Production of 2-substituted benzo(b)thiophene and its intermediate

Abstract: PURPOSE: To industrially and advantageously obtain the subject compound useful as a raw material, etc, for medicines, agricultural chemicals and functional polymers by reacting a halobenzaldehyde with an alkali metallic hydrosulfide or an alkali metallic sulfide in the presence of a polar solvent and then reacting the resultant compound with a halo compound CONSTITUTION: A halobenzaldehyde (eg 2-bromobenzaldehyde) is made to react with an alkali metallic hydrosulfide (eg sodium hydrosulfide) or an alkali metallic sulfide (eg sodium sulfide) in the presence of a polar solvent such as N,N-dimethylformamide to provide 2-mercaptobenzaldehyde or its alkali metallic mercaptide, which is then made to react with a halo compound (eg chloroacetone) expressed by the formula XCH 2 COY (X is Cl or Br; Y is CH 3 , OH, ONa, OK, OCH 3 or OC 2 H 5 ) to afford the objective 2-substituted benzo[b]thiophene (eg 2-acetylbenzo[b]thiophene), expressed by the formula and useful as an intermediate for medicines, agricultural chemicals, functional polymers, etc COPYRIGHT: (C)1993,JPO&Japio

Discoloration of Dental Cements and Composites in a Sulfide Solution

Abstract: In an early study the discoloration of certain hardened silicate cements, after exposure to an atmosphere of hydrogen sulfide (H2S) for 24 h at room temperature, was ascribed to the formation of dark-colored sulfides of base metal impurities (Paffenbarger et al. JADA 25, 32, 1938). A recent study noted that, in general, silicate and glass ionomer cements were more prone to color shifts than composites after exposure to H2S for 9 weeks (Sugawara, Ph. D. Thesis, Nihon Univ.). The aim of the present study was to devise a simple, aqueous sulfide exposure test for esthetic restorative materials. The general procedure was to expose specimen disks to a 0.1% (w/v) sodium sulfide solution, adjusted to pH 9, for 1-7 days at 37° or 55°C. The 55°C-Na2S exposure was designed as an accelerated test. Materials studied included : 1 silicate and 2 silicophosphate cements of known lead content, a glass ionomer cement (FIIF), several commercial composites and an experimental, hydrophilic composite. Known amounts of base metal contaminants in the form of appropriate salt solutions were added to the liquid components of FIIF and the composites. Specimens exposed to distilled water under the same conditions served as controls. Exposure to the aqueous sulfide medium resulted in the following ranking in order of decreasing discoloration : Glass ionomer cement> silicophosphate cement> silicate cement> hydrophilic composite> hydrophobic composite. Generally, the results of the aq. Na2S test paralleled those obtained with H2S. The degree of discoloration is dependent on a number of factors : the nature, concentration and leachability of the metal impurities, and the hydrophilicity and permeability to sulfide of the esthetic restoratives.

Enhanced thermal and ignition stability azide gas generant

Abstract: Multiple processes and apparatuses for improving the prior system of making gas generant pellets or tablets made of sodium azide, molybdenum disulfide and sulfur wherein powdered ingredients thereof are slurried in water, subjected to wet grinding, spray dried to a powdered material which is molded into pellets or tablets which find use in vehicle crash bags or inflators. The first improvement to the old process and apparatus involves adjusting the basicity of the water to a pH of greater than 8.0 up to about 12.5 via the addition of sodium hydroxide, followed by the addition of sulfur and molybdenum disulfide and finally the sodium azide whereby azide addition is made to a basic mixture of the other ingredients thereby keeping hydrazoic acid concentration levels below about 3×10EXP(-3) moles per liter. The second improvement to the old process and apparatus involves (1) softening the water before its use in slurrying the powdered ingredients to remove undesirable Ca and Mg ions and/or (2) adding sodium sulfide and/or tri-sodium phosphate to the slurry to precipitate any remaining undesirable Ca, Mg, Pb, Fe, Mn and Cu ions as non-hazardous compounds. Each of these metal ions is reduced to no more than about 25 ppm or less. Also these two improvements are joined together to form a system wherein even better safety results occur. The improvements not only extend to the final product produced, but to the intermediates at the slurry stage as well as at the spray dried stage, which products differ due to significant elimination or minimization of hydrazoic acid and other contaminant metal ion species above mentioned.

Enhanced thermal and ignition stability azide gas generant, and process and apparatus for making

Abstract: OF THE DISCLOSURE Multiple processes and apparatuses are described for improving the prior system of making gas generant pellets or tablets made of sodium azide, molybdenum disulfide and sulfur wherein powdered ingredients thereof are slurried in water, subjected to wet grinding, spray dried to a powdered materialwhich is molded into pellets or tablets which find use in vehicle crash bags or inflators. The first improvement to the old process and apparatus involves adjusting the basicity of the water to a pH of greater than 8.0 up to about 12.5via the addition of sodium hydroxide, followed by the addition of sulfur and molybdenum disulfide and finally the sodium azide whereby azide addition is made to a basic mixture of the other ingredients thereby keeping hydrazoic acid concentration levels below about 3 x 10EXP(-3) moles per liter. The second improvement to the old process and apparatus involves (1) softening the water before its use in slurrying the powdered ingredients to remove undesirable Ca and Mg ions and/or (2) adding sodium sulfide and/or tri-sodium phosphate to the slurry to precipitate any remaining undesirable Ca, Mg, Pb, Fe, Mn and Cu ions as non-hazardous compounds. Each of these metal ions is reduced to no more than about 25 ppm or less. These two improvements are joined together to form a system wherein even better safety results occur. The improvements not only extend to the final product produced, but to the intermediates at the slurry stage as well as at the spray dried stage, which products differ due to significant elimination or minimization of hydrazoic acid and other contaminant metal ion species above mentioned.

Polyarylene sulfide-added carbonaceous fiber

Abstract: PURPOSE:To provide the title fiber constituted by carbonaceous fiber of specified diameter produced by vapor growth process with polyarylene sulfide portion bound and added thereto, having high dispersibility in and affinity for solvents, rubbers, resins such as polyphenylene sulfide resin. CONSTITUTION:The objective fiber constituted by carbonaceous fiber 0.01-4 (pref. 0.02-1) mum in diameter produced by vapor growth process with polyarylene sulfide portion bound and added thereto. The binding and addition of the polyarylene sulfide portion to the carbonaceous fiber can be accomplished, for example, by the following process: firstly, halogen-bound-and added carbonaceous fiber is synthesized; and this fiber is then reacted by heating with sodium sulfide in combination with a dihaloaromatic compound in a polar solvent.

Recovering method for silver from photographic processing liquid

Abstract: PURPOSE:To recover silver as a silver ion-contg. soln. having comparatively high concn. by electrolyzing photographic processing liquid to deposit metallic silver on a cathode and impressing reverse current in an alkaline soln. and dissolving this metallic silver. CONSTITUTION:While supplying photographic processing liquid contg. silver ion and thiosulfate ion to an electrolyzer main body 2 via a base plate 8, electricity is conducted. Silver ion is reduced in the cathodically polarized part of a fixed bed 5 and deposited as metallic silver. The processing liquid is discharged from a cover body 7 and resupplied to the electrolyzer main body 2 from the bottom plate 8 via a circulation pipe 9. When recovery of metallic silver on the cathode is finished, processing liquid is substituted for an alkaline soln. having >=10pH. Polarities between the electrode terminals 3, 4 are reversed and electrolysis is performed. Metallic silver deposited to the upper part side of the fixed bed 5 is anodically polarized and dissolved in an electrolyte as silver ion. At this time, since silver sulfide deposited on the fixed bed 5 is converted into sodium sulfide or sodium hydrosulfide, a high-concn. silver ion soln. is obtained.

Kinetics of anthraquinone reduction with sodium sulfide in alkaline medium

Abstract: The kinetics of anthraquinone reduction with sodium sulfide in alkaline medium has been studied in a reactor by performing kinetic runs at different temperatures, sodium sulfide concentrations, initial average radius of anthraquinone particles, and sodium hydroxide concentrations. The product was the disodium salt of 9,10-dihydroxyanthracene. The kinetic data treatment was carried out by using the isothermal shrinking-core model for solid-fluid reaction with changing particle size. A reaction rate expression was proposed

Production of alkylene thioether-arylene thioether copolymer

Abstract: PURPOSE:To obtain the title copolymer excellent in flexibility, etc., by reacting a polyarylene thioether with an alkali metal sulfide and copolymerizing the resulting depolymerized product with a specific dihalogen-substd. aliph. compd. CONSTITUTION:A polyarylene thioether contg. recurring units of formula I (Ar is arylene) is reacted with arc alkali metal sulfide (e.g. sodium sulfide) in a hydrous polar org. solvent (e.g. N-methylpyrrolidone) to effect depolymn. of the same. The resulting compd. having an alkali thiolate group is copolymerized with a dihalogen-substd. aliph. compd. (e.g. a 1,3-dihalopropane) of formula II (X1 and X2 are each a halogen; R1 to R4 are each H, or 6C or lower alkyl; and R5 is a 1-200C aliph. compd. residue) and, if necessary, an alkali metal sulfide in a hydrous polar org. solvent to obtain an alkylene thioether-arylene thioether copolymer. This copolymer is excellent in solubility in solvents, heat resistance, etc.

Improved sulfurized olefin extreme pressure/antiwear additives and compositions thereof.

Abstract: Reaction products of sulfur, olefins and sodium sulfide hydrates are improved extreme-pressure/antiwear additives for lubricants and liquid hydrocarbyl fuels. These products contain no or substantially no dithiolethiones.

Method and apparatus for thorough treatment of waste electroplating liquid

Abstract: Ferrous chloride is used as flocculant and iron chloride, sodium sulfide and potassium hydroxide respectively as inhibitor (i.e. protector) and catalyst. The cyanogen and six-valence Cr are removed respectively under each proper condition. The apparatus uses the venturi principle in chemicals dose and pH test, and an integrated process of rotation and stabilizing flow in deposition and filtering, so featuring complete functions, novel and simple structure, and no secondary pollution.

Reactivity of aryl chlorides with sodium sulfide in the synthesis of aromatic polyamidethioethers

Abstract: The synthesis of aromatic copolyamidethioethers by reaction of dichlorobenzanilides with Na2S has been studied. The reactivity of chlorine atoms is strongly dependent on the nature of the substituent in para position. It is related to the 13C NMR shifts of the relative carbons-the more deshielded, the more reactive-and hence to charge densities, agreing with aromatic nucleophilic substitution mechanisms. The results are discussed in relation to the various mechanisms which have been put forward for the reaction of Na2S with 1, 4-dichlorobenzene (PPS synthesis).

Bleaching method for cellulose pulp by oxygen

Abstract: PURPOSE:To enable the white liquor in the recovering process in kraft digestion method to be used and the sulfurization degree of digestion white liquor to be retained at a certain level by bleaching, with oxygen, cellulose pulp in the presence of a specific aqueous alkaline solution. CONSTITUTION:When cellulose pulp is to be bleached with oxygen in the presence of an aqueous alkaline solution, such a solution is used as said aqueous alkaline solution that the sodium sulfide contained in an alkaline digestion liquor is oxidized by air or oxygen into sodium polysulfide and sodium thiosulfate.

Image developing method utilizing sodium sulfide and ammonium polysulfide developer solution whereby exposed copper substrate surface changes color

Abstract: An image development method is disclosed. In the method, a photoresist layer on a metal surface is exposed for development. The developer then used is a solution which will both develop the photoresist image and cause any exposed metal surface to change to a predetermined color. The development process then proceeds until the predetermined color is exposed whereupon the process ceases. The preferred metal is copper and the preferred developer is an aqueous solution of sodium sulphide and ammonium polysulfide.

Production of granular polyarylenesulfide having high molecular weight

Abstract: PURPOSE:To obtain the high molecular weight polymer having good physical properties and molding properties without giving bulky product by subjecting a sulfur source to polycondensation with a dihaloaromatic compound in an organic polar solvent in the presence of a polymerization assistant under specific conditions. CONSTITUTION:A sulfur source (preferably sodium sulfide) is subjected to polycondensation with a dihaloaromatic compound (preferably compound containing >=80mol% p-dichlorobenzene) in an organic polar solvent (e.g. DMF) in the presence of a polymerization assistant (preferably lithium chloride) while keeping the temperature from definite time before completion of polycondensation reaction to the point of time of completion of polycondensation reaction to 220-248 deg.C to provide the aimed polymer.