Showing papers on "Sodium sulfide published in 1986"

Sulfate reduction process useful in coal gasification

Abstract: A carbonaceous material, such as coal, is gasified through the catalytic action of an alkali metal salt. The alkali metal is provided as a sulfate which is converted to a sulfide during gasification. In one embodiment, sodium sulfate is converted to sodium sulfide at a temperature effective to form a transitory melt condition at an interface which obtains coal gasification at relatively low temperatures and material residence times for the reaction. An alkaline earth sulfate, such as a gypsum, may be concurrently converted to a sulfide during gasification. The alkali metal sulfide may then be regenerated to a sulfate for process reuse while converting the alkaline earth to a carbonate for environmentally safe disposal with concurrent recovery of valuable sulfur. The evolved carbon gases may be used for fuel, for process feed chemicals, or the like.

Role of sodium sulfide in the flotation of oxidized copper, lead, and zinc ores

Abstract: This paper reviews uses of sodium sulfide in the flotation of oxide minerals of copper, lead, and zinc. The activation and depression effects of sodium sulfide are of particular importance because of their applications with oxidized lead and copper ores. In spite of its industrial importance, the nature of the heterogeneous reactions between sulfide ions in solution and the surface of oxidized minerals has not been fully understood. Hence, proposed mechanisms of the sulfide action in flotation, methods of measuring and monitoring sodium sulfide in flotation pulps, and variables influencing the sulfide addition are analyzed. Recent studies on sodium sulfide addition to flotation pulps, monitoring its concentration, and the optimum dosage control using platinum and/or sulfide specific ion electrodes are discussed.

Process for preparation of polyarylene thioethers having high melt crystallization temperature

Abstract: Polyarylene thioethers having increased melt crystallization temperature are produced by subjecting a polyarylene thioether recovered from a conventional polycondensation of dichlorobenzene with sodium sulfide to a treatment with an aqueous non-oxidative strong acid such as HCl, H₂SO₄ or H₃PO₄ or with an aqueous salt of the non-oxidative strong acid with a weak base such as ammonia.

Formation of uranium oxide sols in bicarbonate solutions

Abstract: Colloidal particles of hydrated uranium oxide were formed by reducing a solution of sodium tricarbonatouranate(Vl) with sodium sulfide. These particles were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, and Fourier Transform infrared spectroscopy. Particle size was determined by photon correlation spectroscopy. Depending on conditions, the particles that formed consisted of either a mixed valency (U(IV) and U(VI)) uranium oxide or a complex uranium(VI) hydrous oxide. The mixed valency uranium oxide particles showed nearly spherical morphology, whereas the complex uranium(VI) hydrous oxide consisted of irregularly shaped particles. Electrokinetic measurements showed that both types of particles were negatively charged in near-neutral media.

Kinetics of hydrogen production from illuminated cadmium sulfide-platinum-sodium sulfide dispersions

Abstract: The production of hydrogen (H/sub 2/) upon illumination of transparent CdS/Pt/Na/sub 2/S dispersions has been studied over the complete life of the catalyst and as a function of the initial concentration of Na/sub 2/S. Our results indicate that the observed decline in, and eventual cessation of, H/sub 2/ production results from the depletion of the electron donor (Na/sub 2/S) and the deactivation of the catalyst (poisoning). Donor depletion dominates when low initial concentrations of donor are used (less than ca. 4 x 10/sup -3/ mol dm/sup -3/), whereas with higher concentrations catalyst poisoning is the main deactivation pathway. Evidence is presented which suggests that polysulfides are responsible for the deactivation of the catalyst. A model reaction scheme is developed which accounts for the experimental observations and provides a detailed description of the Lebenslauf of the catalytic system.

Poly(phenylene sulfide): polymerization kinetics and characterization

Abstract: The polycondensation kinetics of aromatic nucleophilic substitution on 1,4-dichlorobenzene by sodium sulfide has been investigated at 195°C in N-methyl pyrrolidone. The reaction follows second-order kinetics. The rate is bimodal with an initial slow rate till 50% conversion followed by a faster rate between 50 and 97% conversion. The specific reaction rates have been evaluated as 3.97 × 10−3 L m−1 s−1 and 1.02 × 10−2 L m−1 s−1 for the initial and later part (50–97%) of the reaction. The development of the degree of polymerization with reaction time was followed by end-group analysis and intrinsic viscosity measurements of polymer samples collected at different conversions. The reaction differs from conventional polycondensation reactions in two aspects. Polymer formation occurs at low conversions, and a significant amount of uncreacted monomer is present even at very high conversions. Unlike other precipitation polymerization reactions, the polymer chain continues to grow even after precipitation.

Effect of sulfides on the electrochemical behavior of aisi 304 stainless steel in neutral buffered solutions

Abstract: This work studied electrochemical behavior in buffered neutral media containing sodium sulfide and mixtures of sodium chloride and sodium sulfide using potentiodynamic techniques complemented with scanning electron microscopy (SEM) and energy dispersive x-ray analysis (EDXA) to obtain information on pitting. The presence of sodium sulfide hinders oxide growth and decreases the amount of ferric oxide formed which leads to a complex sulfide/oxide film. The presence of the sulfide/oxide film on the surface reduces the breakdown resistance as a result of chloride ions shifting the breakdown potential toward more negative values.

Dissolving reactions of anthraquinone at high temperatures

Abstract: The conversion of anthraquinone (AQ) to anthrahydroqutnone (AHQ) was determined by mixing AQ with typical pulping constituents (or models of) in a flow-through cell and filtering while hot. The very limited solubility of AQ in W NaOH at 160°C is increased significantly (by conversion to soluble AHQ−2) with glucose, kraft lignin, or sodium sulfide. The flow-through filtering cell has also been used to estimate effective methods for reducing AQ and AQ-analogs to AHQ species and to attempt to recover AQ from pulping liquors.

Sodium sulfide analyzer

Abstract: The invention provides a method and apparatus for measuring the sodium sulfide content of liquid industrial process streams. According to this method, a sample of the liquid is passed through a heated filter to remove solids and reduce viscosity and a portion of the sample is then mixed with carbon dioxide to generate hydrogen sulfide gas. The hydrogen sulfide gas is separated from the reacted liquid sample, and a portion of the gas is mixed with dilution air and then analyzed quantitively for hydrogen sulfide.

Corrosion of dental amalgams in solutions of sodium chloride, sodium sulfide and ammonia

Abstract: — Specimens were prepared from three different dental amalgams and were immersed in 0.5% aqueous solutions of sodium sulfide, ammonia and sodium chloride. Every month and over a 6-month experimental period the solutions were replaced with fresh electrolyte and were analyzed in an atomic absorption spectrophotometer with respect to their content in silver, mercury, copper, tin and zinc. In sulfide solutions large amounts of tin and mercury were released from the amalgams while none of the other elements could be detected. Copper, tin and mercury were mostly dissolved in ammonia solutions. An increased silver dissolution could also be observed. Zinc was the first element to be released in sodium chloride solutions. After a 4-month immersion, considerable amounts of copper and mercury could also be found in the same solutions.

Polymerization by phase‐transfer catalysis 3: Poly(1,4‐oxylylene thioethers) synthesis

Abstract: Poly(1,4-oxylylenethioethers) were synthesized from 2,5-disubstituted-1,4-bis(chloromethyl)-benzenes and sodium sulfide under phase-transfer conditions. The polythioethers were characterized by elemental analysis and infrared spectroscopy. The effect of the catalyst, solvent, and temperature were studied. Their glass transition temperature and thermal decomposition were determined.

Catalytic and stoichiometric hydrogen formation by UV irradiation of sodium and zinc sulfide

Abstract: UV irradiation (λ ⩾ 248 nm) of sodium sulfide in aqueous solution leads to hydrogen and disulfide, Φ(H2) = 0.34 at λ = 254 nm. Light absorption occurs by HS− which affords the solvated electron and the HS radical as indicated by flash photolysis and pulse radiolysis. In the presence of formate, hydrogen evolution becomes catalytic with respect to HS−, Φ(H2) = 0.12 at λ = 254 nm. Deuteration experiments indicate that hydrogen formation occurs partially via hydrogen atoms which abstract hydrogen from formate. The latter is finally oxidized to give carbonate. When methanol is used instead of formate, there are produced ethanol, ethylene glycol, methane, and formaldehyde in addition to hydrogen and carbonate. It is shown that the direct homogeneous photolysis of HS− may contribute significantly to the heterogeneous zinc sulfide-catalyzed hydrogen evolution in the presence of sodium sulfide when performed in quartz vessels. Katalytische und stochiometrische Bildung von Wasserstoff bei der UV-Bestrahlung von Natrium- und Zinksulfid UV-Belichtung (λ ⩾ 248 nm) von Natriumsulfid in wasriger Losung fuhrt zu Wasserstoff und Disulfid, Φ(H2) = 0.34 bei λ = 254 nm. Die Lichtabsorption erfolgt durch HS−, dessen Primarreaktion zum HS-Radikal und solvatisierten Elektron durch Blitzlichtspektroskopie und Pulsradiolyse untersucht wurde. In Gegenwart von Natriumformiat wird die Wasserstoffentwicklung katalytisch in bezug auf HS−, Φ(H2) = 0.12 bei λ = 254 nm. Deuterierungsexperimente deuten darauf hin, das die Wasserstoffbildung teilweise uber eine Abstraktionsreaktion zwischen Wasserstoffatomen und Formiatmolekulen erfolgt. Letztere werden schlieslich zu Carbonat oxidiert. Wird Methanol statt Formiat verwendet, werden zusatzlich zu Wasserstoff und Carbonat noch Ethanol, Ethylenglycol, Methan und Formaldehyd gebildet. Die direkte, homogene Photolyse von HS− tragt betrachtlich zur heterogenen, Zinksulfid-katalysierten Wasserstoffentwicklung bei, wenn letztere in Quarzapparaturen in Gegenwart von Natriumsulfid durchgefuhrt wird.

Production of polyarylene sulfide

Abstract: PURPOSE:To produce the titled compound without causing clogging of pipes, etc., by using simple equipment, by reacting a dihaloaromatic compound with an alkali metal sulfide in a solvent in an agitation tank of a specified structure and evaporating liquid components from a reaction slurry in the same tank. CONSTITUTION:A dihaloaromatic compound (e.g., p-dichlorobenzene) is polycondensed with an alkali sulfide (e.g., sodium sulfide in a solvent in an agitation tank equipped with an impeller of a diameter corresponding to 80-99% of the inside diameter of the tank and provided with heating and cooling means. After completion of the reaction, a liquid component is evaporated from the reaction slurry in the same agitation tank to separate a solid component, and a given amount of pure water is added to the solid component to dissolve the alkali metal halide contained in the solid in water. The mixture is centrifuged to produce a polyarylene sulfide. By recovering a solvent subsequently to the reaction in the same agitation tank, the titled compound can be produced with simple equipment without any trouble, such as clogging of pipes during transfer of the reaction product and the recovered solvent can be purified when the vaporized component is fractionated in an attached distillation tower.

Method of extracting gallium from dissociation mother liquor from the production of alumina

Abstract: The process consists in passing CO2 into the mother liquor remained after separation of aluminium hydroxide by carbonation dissociation treatment complete carbonation dissociation, gallium and aluminium are thus precipitated as amorphous hydrate. Separation of the precipitate removes most part of Na2O. Introducing slaked lime into the precipitate to remove alumina, a gallium-rich solution is produced. On passing CO2 into the solution again, a gallium-rich precipitate is obtained. Dissolving the gallium-rich precipitate with sodium hydroxide liquor and adding sodium sulfide to remove heavy metals, a solution containing 3-9 grams gallium per liter for electrolysis is obtained. This solution is electrolyzed in an electrolytic cell with stainless steel anode and cathode, gallium is deposited on the cathode. By treating with hydrochloric acid, gallium metal with a purity of 99.99-99.999% can be produced.

Preparation of coal liquefying catalyst

Abstract: PURPOSE:To obtain a highly active fine coal liquefying catalyst, by mixing sulfur with the solid separated from a slurry mixture consisting of a sulfur ion- containing alkaline aqueous solution and an iron ion-containing acidic aqueous solution before reacting both of them at 200-700 degC CONSTITUTION:A sulfur ion-containing alkaline aqueous solution containing sodium sulfide, ammonium sulfide or potassium sulfide in concn of 01-4mol as a sulfur ion is prepared while an iron ion-containing acidic aqueous solution containing iron acetate, iron sulfate or iron nitrate in concn of 01-4mol as an iron ion and adjusted to pH 2-7 is prepared and both solution are mixed to form a slurry From this slurry, a fine solid with a particle size of 05-2mum is obtained by solid-liquid separation and sulfur is mixed with said solid while the resulting mixture is reacted at 200-700 degC to prepare a coal liquefying catalyst

Process for production of high molecular-weight polyarylene sulfides

Abstract: OF THE DISCLOSURE A process for the preparation of a high-molecular-weight polyarylene sulfide, which comprises subjecting an alkali metal sulfide such as sodium sulfide and a dihalo aromatic compound such as dichlorobenzene to dehalogenation sulfidation reaction in an organic amide solvent, wherein the reaction is carried out by using a reaction vessel in which at least the portion which the reaction liquid contacts is made of titanium, through at least the following two steps: (1) the step of carrying out the reaction at a temperature of 180 to 235°C in the presence of water in an amount of 2.4 to 10 moles per mole of the alkali metal sulfide so that the conversion of the dihalo aromatic compound is at least 50% and the melt viscosity of the formed polyarylene sulfide does not exceed 500 P, and (2) the step of elevating the temperature to 245 to 290°C in the presence of water in an amount of 2.5 to 10 moles per mole of the alkali metal sulfide by or without adding water to the reaction system and carrying out the reaction. The titanium reaction vessel is used for at least the step (1) and, preferably, for both the steps (1) and (2). The two-step reaction is advantageous in producing high molecular weight polyarylene sulfide.

Corrosion of Nickel‐200 and AISI‐1008 Steel in Sodium Polysulfides and Sulfur at 350°C

Abstract: Essais de corrosion dans Na 2 S 5 , Na 2 S 4 et Na 2 S 3 , pendant 1 a 25 h. Cinetique de corrosion et morphologie de la couche de corrosion

Production of sodium sulfide or sodium hydrosulfide

Abstract: PURPOSE: To easily obtain the titled high purity compd. by reacting vapor of single sulfur with an excess of H 2 over the theoretical amt. in the presence of a catalyst and by bringing the resulting gaseous H 2 S contg. unreacted H 2 into contact with an aq. NaOH soln. CONSTITUTION: High purity sulfur S of ≥99.5% purity produced by the Claus process or other process is put in a melting vessel 1, melted by heating with a steam heater or the like, sent to an evaporator 3 by a pump 2 and evaporated by heating to about 300°C. High purity H 2 is fed to the evaporator 3 through an H 2 compressor 8 and a line 9 by an amt. satisfying ≥1 molar ratio of H 2 to S, e.g., 5W20 molar ratio during circulation of H 2 . The high purity H 2 is well mixed with generated sulfur vapor and introduced into a reactor 4 packed with a catalyst such as Co-Mo or Ni-Mo supported on an alumina carrier. In the reactor 4, they are brought into a reaction at 250W500°C under 0.1W10kg/cm 2 G pressure to obtain gaseous H 2 S. This gaseous H 2 S contg. unreacted H 2 is fed to the lower part of an absorption reaction tower 6 through a heat exchanger 5 and 20W30% aq. NaOH soln. is fed to the upper part of the tower 6 and brought into countercurrent contact with the gaseous H 2 S. Part of the soln. accumulated on the bottom of the tower 6 is drawn out by a pump 7, Na 2 S or NaHS is recovered and the remainder is circulated. COPYRIGHT: (C)1988,JPO&Japio

4-Mercaptobenzonitriles and process for their preparation

Abstract: 4-Mercaptobenzonitrile werden hergestellt, indem man die entsprechenden 4-Halogenbenzonitrile mit Natriumsulfid oder Natriumhydrogensulfid in Gegenwart eines inerten organischen Losungsmittels umsetzt und anschliesend ansauert. 4-Mercaptobenzonitrile be prepared by reacting the corresponding 4-Halogenbenzonitrile with sodium sulfide or sodium hydrogen sulfide in the presence of an inert organic solvent and then acidifying. Die so zuganglichen 4-Mercaptobenzonitrile sind mit Ausnahme des unsubstituierten 4-Mercaptobenzonitrils neu und konnen als Zwischenprodukte zur Herstellung von nematischen flussig-kristallinen Produkten, Herbiziden und Pflanzenwachtstumsregulatoren verwendet werden. The so accessible 4-Mercaptobenzonitrile are new with the exception of the unsubstituted 4-Mercaptobenzonitrils and can be used as intermediates for the preparation of nematic liquid-crystalline products, herbicides and Pflanzenwachtstumsregulatoren.

2-aminophenol derivative, its preparation and remedy containing same as active ingredient

Abstract: NEW MATERIAL:A compound of formula I (R , R are H, allyl, 4-methoxybenzyl; R is n-pentyl, formula II, formula III). EXAMPLE:2-Amino-4-(2-benzofuranylthio)phenol. USE:It is used as a preventive or remedy for a variety of inflammations caused by prostaglandins and a variety of allergic inflammation caused by leucotriene. PREPARATION:The nitro group in the compound of formula IV is selectively reduced into an amino group, e.g., in the presence of a nickel or platinum catalyst with hydrogen or with iron, zinc, titanium trichloride in benzene, with sodium sulfide in water or aqueous alcohol or hydrosulfite with aqueous ammonia to give the compound of formula I.

Treatment by flocculation and precipitation of waste water

Abstract: PURPOSE:To prevent the elution of mercury, cadmium and lead from sludge by mixing sulfides with the sludge separated in a precipitation vessel. CONSTITUTION:In a sludge concentrating vessel 12 or a solfide mixing vessel 19 provided with a sulfide feeding pipe 17 and a stirring apparatus 18, sulfides such as sodium sulfide, sodium hydrogensulfide and sodium polysulfide are mixed with the concentrated sludge. Thereby, all parts of mercury, cadmium and lead incorporated in the dehydrated sludge are hardly eluted owing to the sulfides thereof.

Wet technology for preparing sodium pyroantimonate from fine antimony ore

Abstract: This technology suits for fine ore of antimony sulfide with high content of Pb, As and Se, or antimony sulfide only, or mixed fine Sb ore. Using aq. solution of sodium sulfide to extract Sb from ore and turn it into soluble Sb compound. After filtering out residue, oxygen or air is blown into the soluble Sb compound (soluble Cu salt and paradioxybenzene are added as catalyst), and the Sb compound is oxidized to be insol. sodium pyroantimonate. Finally, the industrial pure products of sodium pyroantimonate can be obtd. by filtration, washing and drying.

Electrochemical refining method of liquid sodium

Abstract: PURPOSE:To utilize the electromotive force generated from battery reaction to refine liquid sodium by combining and using two sells made in the construction each consisting of the cathode chamber and anode chamber partitioned by a solid electrolyte. CONSTITUTION:The cathode chamber 2A and anode chamber 3A of the 1st sodium.sulfur battery 1A is partitioned by the solid electrolyte 4A. The impurity- contg. liquid sodium is put into the chamber 2A and the mixture composed of molten sulfur and liquid sodium is put into the chamber 3A. The electrolyte 4A allows the passage of only the Na ions to the chamber 3A and therefore the sulfur changes to the sodium sulfide in the chamber 3A, thus generating the electromotive force. The refined sodium sulfide is put into the anode chamber 3B of the 2nd battery 1B and the liquid sodium contg. no impurities is put into the chamber 2B isolated by the solid electrolyte 4B. The charging reaction arises when the electromotive force generated by the 1st battery is impressed, then the Na ions migrate to the chamber 3B and are regenerated to pure metallic Na.

Production of polyarylene polyether

Abstract: PURPOSE:To produce a polyarylene polyether without necessitating dehydration treatment, in high efficiency, by reacting a dihalobenzenoid compound with a dialkali metal salt of diphenol in the presence of a quaternary phosphonium salt catalyst. CONSTITUTION:The polyarylene polyether of formula I [R and R are H, halogen or 1-8C hydrocarbon group; a and b are 0-4; Ar is bivalent aromatic group of formula II, formula III, etc. (R -R are H or 1-8C hydrocarbon group; c-e are 0-4; Y is single bond, O, S, etc.); Z is SO, SO2, etc.; m and n are numbers satisfying the formula IV] containing sulfur in the main chain, can be produced by reacting (A) a dihalobenzonoid compound having electron- attracting group at o- and/or p-position based on the halogen atom with (B) a dialkali metal salt of a diphenol (preferably hydroquinone, etc.) and/or an alkali metal sulfide (preferably sodium sulfide) in the presence of (C) a quaternary phosphonium salt catalyst. The amount of the component A is 0.7-1.3mol per 1mol of the component B.

Aromatic polysulfone/polythioethersulfone copolymer and its production

Abstract: PURPOSE:The reaction between dihalodiphenylsulfone, diphenols and an alkali metal sulfide gives a novel copolymer which can be formed into precise parts such as electric parts, because of its high heat resistance, mechanical properties and melt flowability. CONSTITUTION:(A) A diphenol whose aromatic residue is formulas I-III (R -R are H, hydrocarbon of 1-8 carbon atoms; c-e are 0-4; f, g are 0-3; Y is O, S, SO) such as hydroquinone is made into its alkali metal salt. Then, the salt is allowed to react with (B) a diaholdiphenyl sulfone of formula IV (X is halogen in the o- or p-positon; R , R are H, halogen; a, b are 0-4) such as bis (4-chlorophenyl) sulfone and (C) an alkali metal sulfide such as sodium sulfide in a solvent such as dimethyl sulfoxide to give the objective copolymer of formula V (m, n satisfy 0

Preparation of trithiocyclohexene chlorohydric acid

Abstract: The reaction takes place when mixing sodium sulfide with 2-dimethylamine-1-thiosulfyl-3-sodium thiosulfyl-propane at 0-30 deg.C in water and toluene solution. Hydrogen chloride is passed into the organic phase immediately after the latter is separated from the aqueous phase. the white sediment thus obtained, after drying through filtration, is designated as product A, which is actually a novel pesticide of high efficiency, low toxicity and broad range. Its particular function is to kill oncomelania.

Photoassisted Reduction of Carbon and Nitrogen Compounds with Semiconductors

Abstract: The conversion of visible light into the stored energy of chemical fuel was studied, using semiconductors as photosensitizers. The reactions investigated were the reduction of carbonate ions to organic compounds and of nitrogen oxyanions to ammonia. Using suspensions of CdS, ZnS-CdS or TiO2 in 1M KOH and 0.1M Na2S at 61° C, illuminated with a 150W Xe-lamp, we found that there was a slow release of ammonia, 0.014 micromol h−1 cm−2 (illuminated area) which was the same whether the mixture was purged with argon or nitrogen gas. Addition of 0.2M potassium nitrate did not change the rate of release of ammonia. However, addition of potassium nitrite caused a marked increase in the rate of production of ammonia. Using 0.13M potassium nitrite in 1M KOH, 0.1M sodium sulfide at 61° C, the production rate of ammonia was 0.97 micromol/(h cm−2) in the presence of TiO2 (70mg in 70ml reaction solution), 0.60 micromol/(h cm2) in the presence of CdS (same concentration), and 0.55 micromol/(h cm2) in the presence of ZnS-CdS (70mg – 50mg mixture). In the absence of sodium sulfide, and if sodium sulfite was substituted for sodium sulfide, the above photoassisted reduction of nitrite ions to ammonia was negligible. Also, there was no reaction in the dark. With CdS - ZnS in 0.5M potassium carbonate — 0.1M sodium sulfide, illumination caused the production of ammonia, methanol and formaldehyde, at rates of 7.1×10−9, 1.5×10−9 and 0.2×10−9 mol h2212; cm−2, respectively.

Preparation of silver halide emulsion

Abstract: PURPOSE:To enable exact silver ion activity to be measured even if the silver ion concn. in a silver halide emulsion is as low as about 10 mol/l, by using a silver sulfide electrode as a detection control sensor of silver ions. CONSTITUTION:The silver sulfide electrode can be obtained, e.g., by adding silver nitrate into a soln. of sodium sulfide and press molding the precipitated silver sulfide. Hardly soluble silver grains of a silver halide emulsion are prepared by monitoring and controlling pH and PAg with the device widely known in the field of the photographic industry. On the other hand, silver halide includes silver bromide, silver chloride, silver iodide, etc., and preferable diameters of preparable silver halide grains are 0.1-4mum, especially, 0.2-2mum. As the typical silver halide solvents, ammonia, thioethers, compds. having a thiocarbonyl group combining with one of oxygen atoms and a nitrogen atom, etc., are enumerated.