Showing papers on "Sodium sulfide published in 1990"

Enhanced electronic properties of GaAs surfaces chemically passivated by selenium reactions

Abstract: We describe chemical modifications of GaAs surfaces which produce robust selenium layers that significantly enhance the electronic properties of the surface. The terminating layers are produced by depositing elemental selenium on GaAs surfaces under alkaline conditions followed by conversion to selenide and selenate using sodium sulfide. These selenium phases are more stable against photo‐oxidation than their sulfide counterparts. On the chemically modified surface, photoluminescence is enhanced 400× and Raman spectroscopy indicates that surface band bending has been reduced to ∼0.1 eV. X‐ray photoelectron spectroscopy reveals significant AsSe bond formation at the surface and a complicated interfacial structure with selenium present in oxidation states varying from 2− to 4+.

In situ x‐ray photoelectron spectroscopic study of remote plasma enhanced chemical vapor deposition of silicon nitride on sulfide passivated InP

Abstract: The changes in chemical composition and Fermi level position of n‐ and p‐InP surfaces induced by reactions with sodium sulfide and ammonium sulfide solutions and with vapor from ammonium sulfide solution have been characterized by x‐ray photoelectron spectroscopy (XPS). Further, in situ XPS analysis was used to study interfaces formed on sulfide passivated surfaces by remote plasma enhanced chemical vapor deposition of silicon nitride. We found that both indium and phosphorus sulfide phases were formed as a result of exposing InP to sulfide vapor at room temperature. However, most of the surface native sulfides dissolved in water and the resultant surface was then covered with about one monolayer of indium sulfide. Further, reduction in donor states in the upper band gap was evident by these sulfide treatments. However, heating the sulfide passivated sample caused an increase in surface states. Sulfur doping effect was also observed upon heating InP covered with the air oxidation products of the sulfide v...

Process of producing kraft pulping liquor by the oxidation of white liquor in the presence of lime mud

Abstract: Sodium sulfide or hydrosulfide is oxidized to produce sodium polysulfide and sodium hydroxide. Under appropriate conditions, the oxidation may be pursued further to convert all the sodium sulfide into sodium thiosulfate. The oxidation is carried out at or above atmospheric pressure in a mixed reactor or in a pipeline reactor, by sparging oxygen or air, in a mixture of white liquor and lime mud particles produced in the recausticizing plant of a kraft mill.

Kinetics of reactions of benzyl chloride/p-chlorobenzyl chloride with sodium sulfide : Phase-transfer catalysis and the role of the omega phase

Abstract: The reactions of benzyl chloride and p-chlorobenzyl chloride with sodium sulfide were carried out both in the solid-liquid and liquid-liquid modes with phase-transfer catalysis. Tetrabutylammonium bromide was found to be the most efficient catalyst for the system among six catalysts tried. In the solid-liquid mode, the reaction was found to be mass transfer controlled with an activation energy of 2.3 kcal/mol, whereas the liquid-liquid reaction was found to be kinetically controlled with an activation energy of 11.3 kcal/mol. The reactivities of benzyl chloride and p-chlorobenzyl chloride were compared under different controlling regimes. The effect of the Ω phase on the rate of solid-liquid reaction was also studied. A maximum rate enhancement by factors of 12 and 57 was obtained for benzyl chloride and p-chlorobenzyl chloride, respectively, with a calculated amount of water compared to no extra water. The importance of mass-transfer resistance was assessed at the maximum rate.

Process for making an 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 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 state, which products differ due to significant elimination or minimization of hydrazoic acid and other contaminant metal ion species above mentioned.

Electroless nickel-phosphorus plating solution

Abstract: PURPOSE: To improve the stability of an electroless Ni-P alloy plating soln. and to form a uniform plating film having fine luster by adding a ferrocyanogen compd. as well as a known stabilizer to the plating soln. CONSTITUTION: An aq. soln. contg. the water-soluble sulfate, chloride, acetate, nitrate, etc., of Ni as an Ni ion source, a hypophosphite such as sodium hypophosphite as an Ni ion reducing agent and oxycarboxylic acid or dicarboxylic acid as an Ni ion complexing agent is prepd. and 1-30ppm ferrocyanogen compd. such as sodium ferrocyanide or potassium ferrocyanide and 0.1-10ppm, in total, of two ror more among a sulfide such as sodium sulfide or potassium sulfide, an iodic acid compd. such as sodium iodate and a lead compd. such as lead sulfide or lead acetate are added to the aq. soln. This soln. is then adjusted to pH 4.5-6.8 with Na0H, an aq. ammonia soln., etc., to obtain an electroless Ni-P alloy plating soln. COPYRIGHT: (C)1992,JPO&Japio

Cyclization versus polymerization in phase transfer catalyzed polytioetherification

Abstract: Some unexpected results were observed in the phase transfer of catalyzed (PTC) (two phase, aqueous-organic) polymerization of α,ω-dibromoalkanes with sodium sulfide. Alkane dielectrophiles containing fewer than six methylene units give rise to large, and sometimes quantitative, amounts of cyclic thioethers. These cyclic sulfides are formed under “polymerization” conditions and can be minimized by using only the monomer as the organic phase. Alkane dielectrophiles containing more than six methylene units yield only polymer. When a comonomer system composed of a 1:1 mixture of 1,4-dibromobutane (DBB) and 1,8-dibromooctane (DBO) is employed, the resulting copolymer's molecular weight and polydispersity are vastly improved compared to the corresponding homopolymerizations. Microstructurally, this copolymer is formed by complete consumption of DBO and partial incorporation of DBB. The remaining DBB forms tetrahydrothiophene (THT). These two odd and seemingly conflicting results could not be explained by “normal” or “inverse” PTC extraction mechanisms. Support of this new mechanism is given in the PTC polymerization of DBO with sodium sulfide in the presence of a catalytic amount of THT. The resulting polymer is of very high molecular weight and narrow polydispersity; it also does not contain tetramethylene sequences. Using this new mechanism, all results suggest the participation of cyclic sulfides either facilitates cyclic formation or enhance polymer reactivity as controlled by the length of the alkane dielectrophile.

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.

Bimechanistic phase transfer catalyzed polythioetherification

Abstract: Relative concentrations of catalysts, sulfide catalyst structure, and organic phase monomer concentration were studied for the bimechanistic phase transfer catalyzed (BPTC) polymerization of aqueous sodium sulfide with 1,8-dibromooctane (DBO). BPTC is a new phase transfer mechanism which combines the effects of normal phase transfer with “inverse” phase transfer catalyzed reactions. Two catalysts are used: an ammonium salt and a cyclic or acyclic sulfide. With hexadecyltrimethylammonium chloride (CTMAC) and tetrahydrothiophene (THT), the optimum catalyst concentrations were found to be 10 mol-% and 5 mol-%, respectively, per DBO, but each was independent of the other. Diluting the monomer with o-dichlorobenzene did not significantly alter the mechanism's profile, but expectedly lowered obtainable molecular weight. Of five sulfide catalysts examined, pentamethylene sulfide and dimethyl sulfide were the best, producing the highest molecular weight polyaliphatic sulfides with polydispersities Mw/Mn of ca. 1,3.

Directed synthesis of macrocyclic phenylene sulfides

Abstract: A method has been developed for the directed synthesis of macrocyclic phenylene sulfides with 4–8 phenylene sulfide fragments, by condensation of dihaloaromatic compounds of various types with sodium sulfide or dithiophenate. A combination of this method with high dilution techniques has afforded pure macrocycles in high yields, and the macrocycle with six phenylene sulfide fragments in yields as high as 73%.

Oil soluble sulfurized olefins and two temperature zone process for their preparation

Abstract: Sulfurized olefins such as isobutylene which are soluble in hydrotreated oils are prepared by reacting a basic, aqueous alcoholic solution of sodium sulfide with an adduct formed by adding olefin to sulfur monochloride at low temperatures until the mole ratio of olefin to sulfur monochloride is between about 1.7-1.9 to 1.

Production of arylene thioether copolymer

Abstract: PURPOSE: To obtain the title polymer having a high degree of polymerization and excellent solution stability, etc., by polymerizing a prepolymer derived from a polyarylene thioether with a dihaloaromatic compound in a water- containing polar organic solvent. CONSTITUTION: A polyarylene thioether mainly consisting of repeating units of formula I (wherein R 1 is 1-6C alkyl; and (l) is 0 or 1-4) is depolymerized by treatment with an alkali metal sulfide (e.g. sodium sulfide) in a water- containing polar organic solvent (e.g. water-containing N-methylpyrrolidone) to produce a prepolymer having an alkali thiolate group at least at either terminal thereof. This prepolymer is polymerized with a dihaloaromatic compound (e.g. p-dichlorobenzene) of formula II (wherein R 2 is alkyl, aryl or alkoxy; (j) is 0 or 1-4; and X is halogen) in a water-containing polar organic solvent to obtain an arylene thioether polymer. COPYRIGHT: (C)1992,JPO&Japio

Block copolymer, its production and resin composition

Abstract: PURPOSE:To produce a block copolymer of improved heat resistance by forming a polyphenylene sulfide-containing reaction solution in the first step and performing the formation and bonding of a phenylene sulfide ketone part in the second step by using the reaction solution. CONSTITUTION:An aprotic polar organic solvent (e.g., N-methyl-2-pyrrolidone) containing a dihalobenzene (e.g., p-dichlorobenzene) and an alkali metal sulfide (e.g., sodium sulfide) is heated to form a reaction solution containing a polyphenylene sulfide (step 1). A dihaloaromatic ketone (e.g., 4,4'- dichlorobenzophenone) is added to this reaction solution, and the obtained mixture is heated in the presence of an alkali metal sulfide and an aprotic polar organic solvent to form a block copolymer (step 2). Thus, a block copolymer comprising a polyphenylene sulfide part and a polyphenylene sulfide ketone part can be obtained, and this copolymer is excellent in heat resistance.

Preparation of polysulfide

Abstract: PURPOSE: To increase intrinsic viscosity, decrease reaction time, and improve mechanical strengths by conducting the polycondensation of an alkali metal sulfide with a dihalide compd. in the presence of a specific quaternary ammonium salt. CONSTITUTION: An alkali metal sulfide (e.g. sodium sulfide nona-hydrate) and a dihalide compd. of formula I (wherein R 5 and R 6 are each H or a hydrocarbon group; and R 7 is a direct bond or a hydrocarbon group) (e.g. 1,6-dibromohexane) are polycondensed in the presence of a phase transfer catalyst comprising a quaternary ammonium salt of formula II (wherein R 1 to R 4 are each an aliph. alkyl group provided that at least two of them are 6C or higher alkyl) (e.g. trioctylmethylammonium chloride) in a solvent at 50-150°C. COPYRIGHT: (C)1992,JPO&Japio

Anaerobic bacteria immobilizing gel and production thereof

Abstract: PURPOSE: To stably fix anaerobic bacteria while maintaining activity by removing the dissolved oxygen in a gel base material or lowering an oxidation reduction potential. CONSTITUTION: Reducing agents, such as sodium thioglycolate, potassium thioglycolate, cysteine-hydrochloate, sodium sulfide, potassium sulfide, ascorbic acid, sodium sulfite, and sodium hydrogensilfite are charged into the gel base material to stably fix the anaerobic bacteria while holding the same or the reducing agents are charged into a solidifying liquid or washing liquid when the solidifying liquid is required for gelatinization or when washing is required. The dissolved oxygen is decreased to ≤0.1ppm or the oxidation reduction potential is lowered to ≤0mV by charging of the reducing agents in such a manner. Further, the atmosphere is substd. with nitrogen, helium, argon, carbon dioxide, etc., under the perfect anaerobic condition. The utilization to a methane fermentation treatment, etc., is possible and the industrial value is extremely high. COPYRIGHT: (C)1991,JPO&Japio

PPS Preparation. A Kinetic Study and the Effect of Water on the Polymerization

Abstract: A kinetic study on poly (p-phenylene sulfide) formation from p-dichlorobenzene (1) and sodium sulfide reveals that the initiation rection is first order with respect to 1 and sodium sulfide, respectively. Reaction on the surface of solid sodium sulfide has proved to be negligible when the reaction is carried out in the presence of the solid. The time course of the concentration of 1 and its dimer can be explained with a simplified eight step kinetic model for the initial stage, in which each of the step is firest order with respect to the reactant in concern. Kinetic parameters for each of the steps were estimatied. Increase in [Na2S]/[1] ratio causes the increase both in polymer yield and in the degree of polymerization. Presence of a small amount of water enhances cosiderably the rate of polymerization and increases the polymer yield, but the highest degree of polymerization was observed in the presence of water approximately equimolar to 1.

Production of anhydrous sodium sulfide crystal

Abstract: PURPOSE:To obtain dense cubic system anhydrous sodium sulfide crystal having little deliquescence and liability to be oxidized by heating highly hydrated sodium sulfide crystal under a specified combination of pressure, temp. and time. CONSTITUTION:The highly hydrated sodium sulfide crystal is heated at the phase transition temp. from highly hydrated sodium sulfide to sodium sulfide monohydrate + or -10 deg.C under =2hr. Then it is heated at 90-200 deg.C under atmospheric or reduced pressure for >=2hr to obtain the targeted crystal. As raw highly hydrated sodium sulfide crystal, Na2S.6H2O, Na2S.5.5H2O, Na2 S.5H2O, etc., are used. These highly hydrated sodium sulfide crystals are obtd. by concentrating or cooling an aq. soln. of sodium sulfide. The transition from highly hydrated to monohydrated crystal proceeds without melting of the highly hydrated crystal. Therefore, lumping or sticking to a vessel of the raw material is prevented and thus uniform stirring can be easily carried out.

Organomolybdenum compound and use thereof

Abstract: NEW MATERIAL:A compound by formula I (R 1 and R 2 are 4-24C hydrocarbon; X is 0.5-2.3; Y is 3.5-1.7 with the proviso that X+Y=4). USE: An additive for lubricating oil having excellent storage stability and oil solubility. PREPARATION: Carbon disulfide and a secondary amine (e.g. ethyl-tridecylamine) shown by formula II are added to an aqueous solution of molybdenum trioxide or an alkali metal salt of molybdic acid (e.g. sodium molybdate) and an alkali hydrosulfide (e.g. sodium hydrosulfide) or an alkali sulfide (sodium sulfide) having pH8.5-11, preferably pH9.0-10. COPYRIGHT: (C)1992,JPO&Japio

New Approach on Kinetics of Mercury Removal by Sulfide Regenerated Weak Base Anion Exchange Resin

Abstract: The kinetics of mercury removal by a conventional type weak base anion exchange resin, regenerated by sodium sulfide solution was studied. Assuming that the active centers of sulfide regenerated resin are located on the surface of macropores, a mathematical model which explains the extremely high specificity of this resin towards mercury was developed.

Passivation oxide conversion wherein an anodically grown oxide is converted to the sulfide

Abstract: A method of passivation of Hg 1-x Cd x Te and similar semiconductors by surface oxidation (such as anodic) followed by chemical conversion of the oxide to either sulfide or selenide or a combination of both is disclosed. Preferred embodiments provide sulfide conversion by immersion of the oxide coated Hg 1-x Cd x Te in a sodium sulfide solution in water with optional ethylene glycol and the selenidization by immersion in a solution of sodium selenide plus sodium hydroxide in water and ethylene glycol. Also, infrared detectors incorporating such sulfide and selenide passivated Hg 1-x Cd x Te are disclosed.

Method of turning industrial waste containing harmful heavy metal into harmless substance

Abstract: PURPOSE:To prevent harmful metal ion from eluting and carry out landfill waste disposal or marine waste disposal by adding water solution of organic high molecule containing a chemical agent for liberating sulfur ion and carboxylic acid, kneading therein, adding soil cement and solidifying the same or making the same into a solid CONSTITUTION:Water of property volume is added to an industrial waste such as slag containing harmful heavy metal, smuts and slug to form a paste-like material, and a chemical agent for liberating sulfur ion and water solution of organic high molecule containing carboxylic acid are added and kneaded while the material is agitated, and soil cement is added, solidified or made into a solid to prevent harmful metal ion from eluting, and disposed The organic high molecule containing carboxylic acid is chemically adsorbed with sulfide crystallites to bond a number of particles and form strong, rough and large particles, and the molecule is composed mainly of sodium polyacrylic acid and containing amide and ester partly As for the chemical agent for liberating sulfur ion, sodium sulfide, sodium hydrosulfide, sodium polysulfide or the like is used

Optimizing combination process for producing caustic soda

Abstract: This process includes four cyclic steps: producing sodium sulfate from sodium chloride, producing sodium sulfide from sodium sulfate, producing caustic soda and its by-prod.-zinc sulfide from sodium sulfide and zinc oxide, and producing sulfuric acid and its by-prod.-zinc oxide from zinc sulfide. It is featured as follows: a purification is used to sodium sulfide; the mole ratio of sodium sulfide to zinc oxide is 1:(0.96-0.99); a filter aid is used to separate out zinc sulfide and a desulfurizer is used to remove less quantity of sodium sulfide in reaction liquor. Its running in an industrial apparatus whose annual output of caustic soda is 500 tons shows that it has the advantages of feasible technology, better reasonableness and economy, and saving energy.

Polysulfide resin and preparation thereof

Abstract: PURPOSE:To improve heat resistance, moldability, mechanical characteristics, chem resistance etc, by reacting a dihalogeno-benzonitrile with a specified compd CONSTITUTION:The title resin with a reduced viscosity (measured in a soln of 02g/dl in concd sulfuric acid at 30 degC) of 01dl/g or larger and repeating units of the formula is obtd by reacting a dihalogenobenzonitrile (A) (eg 2,6- dichlorobenzonitrile) with an alkali metal sulfide (a) (eg sodium sulfide) and/or an alkali metal salt of trithicarbonate (b) obtd by reacting the component (a) with CS2 in an atomic ratio of the halogen atom of the component A to the alkali metal atom of the component (a) or (b) of 085-115:1 in an aprotic polar solvent (eg N-methyl-2-pyrrolidone), if necessary, in the presence of a catalyst and a reducing agent for 1-10hr

Production of p-aminothiophenol

Abstract: PURPOSE:To readily obtain the above substance which is a raw material intermediate for medicines, engineering plastics, etc., without forming by-products by reacting a p-halogenated nitrobenzene as a starting raw material with sodium sulfide in water solvent containing a surfactant. CONSTITUTION:A p-halogenated nitrobenzene (e.g. p-chloronitrobenzene or p-bromonitrobenzene) is used as a starting raw material and a surfactant is added into water solvent to disperse the raw material therein. Sodium sulfide is subsequently dropped (the sodium sulfide is preferably fed as an aqueous solution and the concentration thereof is 5-30wt.%, especially 15-25wt.% at 20-80 deg.C temperature in dropping with holding time of 0.5-4hr after the dropping). Reductive reaction is then preferably carried out at 85-150 deg.C in an inert gas atmosphere to afford the objective compound.

Hydrotreated oil soluble sulfurized olefins and their preparation

Abstract: Sulfurized olefins such as isobutylene which are soluble in hydrotreated oils are prepared by reacting a basic, aqueous alcoholic solution of sodium sulfide with an adduct formed by adding olefin to sulfur monochloride at low temperatures until the mole ratio of olefin to sulfur monochloride is between 17-19 to 1

pH and conductivity of concentrated aqueous sodium sulfide/sodium carbonate solutions undergoing carbonation

Abstract: The extent of conversion of Na2S to H2S in a concentrated aqueous solution of sodium sulfide and sodium carbonate undergoing carbonation can be monitored by measuring the pH and conductivity. A simple linear equation has been developed to correlate the percentage of Na as Na2S with the temperature, pH, and conductivity. The apparent hydrolysis constants for carbonate and sulfide were calculated at temperatures ranging between 25°C and 65°C, and the reaction enthalpies and entropies determined. Le degre de conversion du Na2S en H2S dans une solution aqueuse concentree de sulfure de sodium et de carbonate de sodium lors de leur carbonation, peut ětre controle en mesurant le pH et la conductivite. On a elabore une equation lineaire simple pour correler le pourcentage de Na comme Na2S avec la temperature, le pH et la conductivite. Les constantes d'hydrolyse apparente pour le carbonate et le sulfure ont ete calculees a des temperatures comprises entre 25 et 65°C, et on a determine les enthalpies et entropies de la reaction.