Showing papers on "Sodium sulfide published in 1996"

Continuous in-situ combination process for upgrading heavy oil

Abstract: The invention relates to an integrated, continuous process for the removal of organically bound sulfur (e.g., mercaptans, sulfides and thiophenes) comprising the steps of contacting a heavy oil, sodium hydroxide, hydrogen and water at a temperature of from about 380°C to 450°C to partially desulfurize the heavy oil and to form sodium sulfide, contacting said sodium sulfide with a transition metal in water to form a transition metal sulfide, sodium hydroxide and hydrogen. The sodium hydroxide is recirculated and the transition metal sulfide is removed. The partially desulfurized, dewatered heavy oil is treated with sodium metal under desulfurizing conditions, typically at a temperature of from about 340°C to about 450°C, under a hydrogen pressure of at least about 50 psi to essentially desulfurize the oil, and form sodium sulfide. Optionally, the sodium salt generated can be regenerated to sodium metal using regeneration technology. The process advantageously produces essentially sulfur-free product oils having reduced nitrogen, oxygen and metals contents and reduced viscosity, density, molecular weight and heavy ends.

Photo-oxidation of sodium sulfide by sulfonated phthalocyanines in oxygen-saturated aqueous solutions containing detergents or latexes

Abstract: The water-soluble zinc and aluminum complexes and the metal-free derivative of tetrasulfophthalocyanine were employed as sensitizers for the photo-oxidation of sodium sulfide under irradiation with visible light in oxygen-saturated aqueous alkaline solutions containing oppositely charged micelles or latex particles With all photosensitizers the oxidation process was strongly enhanced upon irradiation, and sulfate was the final oxidation product Autoxidation as well as singlet oxygen and hydrogen peroxide formed during the photoreaction contribute to the complex overall process The initial step is dominated by energy transfer In contrast, Co(II)-tetrasulfophthalocyanine exhibits catalytic activity in the dark, and no pronounced additional activity under irradiation, with the formation of thiosulfate as oxidation product In this case an electron transfer mechanism occurs according to known results Detergents strongly increase the photoactivity of sensitizers with high aggregation tendency (eg Zn(II)-tetrasulfophthalocyanine) by stabilizing monomeric dispersions and accumulating oxygen and the substrate Latexes increase the photoactivity and simultaneously the photodegradation of the sensitizer, caused by high local accumulation of the sensitizer and consequently also 1 O 2 Al(III)-tetrasulfophthalocyanine, exhibiting a low aggregation tendency in strongly alkaline solutions, shows high photoactivity and photostability even without detergent

Structural and Morphological Characterization of PbS Nanocrystallites Synthesized in the Bicontinuous Cubic Phase of a Lipid

Abstract: We report the synthesis and characterization of monodispersed lead sulfide (PbS) particles with diameters in the range 4−14 nm, using bicontinuous cubic phase as a matrix. It was found, through polarized optical microscopy and small-angle X-ray scattering studies, that the viscous isotropic bicontinuous cubic phase continued to exist in the ternary sodium dioctyl sulfosuccinate (AOT)/water/sodium sulfide (Na2S) system as long as the concentration of aqueous Na2S solution was below 0.5 M. The exposure of this ternary mixture to aqueous 0.40 M lead nitrate (Pb(NO3)2) solution led to the formation of PbS nanocrystallites within the mesophase. A series of PbS particulate samples were synthesized, using different concentrations of aqueous Na2S solutions ranging between 0.025 and 0.30 M, extracted from the lipid matrix and capped by thiol molecules. The structure and diameter of the particles were determined from X-ray diffraction studies. The particle size was found to increase linearly with increase in Na2S c...

Determination of sodium sulfide and sulfidity in green liquors and smelt solutions

Abstract: A rapid method is provided for the on-line determination of sodium sulfide concentration and/or percent sulfidity in green liquors or smelt solutions used for the production of either kraft or sulfite pulp. The method eliminates manual sampling, and the need for frequent equipment maintenance. The method includes the steps of withdrawing samples of a smelt solution or green liquor from the kraft or sulfite manufacturing process, subjecting the samples to near-infrared spectrophotometry over a predetermined range of wave numbers so as to produce absorbance measurements relative to a reference spectrum of either water or a caustic soda-sodium carbonate solution, determining the absorbance shown by different combinations of sodium sulfide, sodium hydroxide, sodium carbonate and sodium chloride concentrations, correlating by multivariate calibration the relationships between the absorbance measurements of unknown samples and the absorbance shown by different combinations of sodium sulfide, sodium hydroxide, sodium carbonate and sodium chloride so that the amount of sodium sulfide and/or the percent sulfidity can be accurately determined for any levels of TTA or chloride present in the liquor.

A Search for the Mechanism of Direct Copper Plating via Bridging Ligands

Abstract: The mechanism of copper deposition by direct plating on a nonconductive substrate has been investigated. Studies using electron spectroscopic chemical analysis show that the immersion of a sodium sulfide solution does lead to the formation of palladium sul ide. Sulfide acts as a bridging ligand ; it can increase the speed of direct plating dramatically. Compounds with similar bridging property were later found to show the same promotion effect in the direct plating process. These compounds include thiourea, sodium thiocyanate, potassium iodide, and sodium cyanide. It was also found that the addition of these compounds could cause a shift of the rest potential. In addition, copper was found to partially dissolve if the current was interrupted. These phenomena can all be explained by the proposed mechanism.

Method of manufacturing 3-mercaptopropylalkoxy silane

Abstract: After reacting sodium sulfide anhydride and hydrogen sulfide, 3-halopropylalkoxy silane represented by the general formula X (CH2)3 Si (OR)a R3-a (I) is added reacted, wherein X denotes Cl or Br; R denotes a methyl, ethyl or propyl group wherein R's can be all identical or different from each other; and "a" denotes an integer 1, 2 or 3.

Simultaneous Sulfur Dioxide Absorption and Hydrogen Sulfide Generation in an Aqueous Solution of Sodium Sulfide

Abstract: In flue gas desulfurization (FGD) processes, elemental sulfur is the desirable end product for SO2 producers located in remote areas, since it is easier to handle and transport. To convert sulfur dioxide to elemental sulfur via the Claus reaction, hydrogen sulfide is needed as a reductant. In the present work, an attempt was made to generate H2S from aqueous sodium sulfide using SO2. The behavior of the Na2S(aq)−SO2(g)−H2S(g) system was studied experimentally and by modeling. A three-stage pattern was observed in a semi flow batch reactor (SFBR) in regard to chemical properties of this system. It was concluded that aqueous Na2S solution can be used to absorb SO2 in flue gas and to generate H2S under conditions of the second stage. The simultaneous SO2 absorption and H2S generation in an aqueous Na2S solution were confirmed using a continuous flow tank reactor (CFTR). To simulate both the SFBR and the CFTR, two mathematical models were developed based on chemical equilibria of acid−base reactions and mass ...

Effects of selected reducing agents on microbiologically mediated reductive dechlorination of aroclor® 1242

Abstract: The effect of various chemical reducing agents on the anaerobic microbial reductive biotransformation of polychlorinated biphenyls (PCBs) was investigated using Aroclor® 1242 at a concentration of 600 μg/g soil and microorganisms eluted from Hudson River sediments. The investigation sought to determine how various reducing agents influenced PCB dechlorination rates, patterns, and acclimation periods. Three reducing agents were incorporated into culture media : amorphous ferrous sulfide, sodium sulfide with sodium thioglycollate, and sodium sulfide with amorphous ferrous sulfide. All cultures were incubated statically under methanogenic conditions and ambient incubation temperatures of about 20°C. Cultures utilizing both sodium sulfide and ferrous sulfide together demonstrated the most extensive removal of meta- and para-chlorines, the highest average dechlorination rate, the greatest dechlorination of tri- and tetrachlorinated biphenyls, and the greatest accumulation of dichlorobiphenyl homologues. Overall, treatments incorporating ferrous sulfide, alone or in combination with sodium sulfide, demonstrated the ability to more effectively dechlorinate tri-ortho-substituted tetrachlorobiphenyls and pentachlorobiphenyls which had commonly positioned chlorines. Under these same conditions, dichlorobiphenyls, which are more amenable to aerobic dechlorination conditions, increased from 25% (molar basis) initially to levels greater than 60%.

Process for the Regeneration of Sodium Hydroxide from Sodium Sulfide

Abstract: The present invention is directed toward a process for regenerating sodium hydroxide (NaOH) from aqueous solutions of sodium sulfide (Na2S) comprising heating aqueous sodium sulfide in the presence of a metal selected from the group consisting of iron and cobalt, for a time and at a temperature sufficient to form a metal sulfide, sodium hydroxide and molecular hydrogen.

Method for fixing heavy metal by hydrothermal treatment of fly ash

Abstract: PURPOSE: To sufficiently fix heavy metals at the time of treating a heavy metal- contg. fly ash with water and/or a heavy metal fixing agent and cement by heat-treating the entire treated material at a specified temp. CONSTITUTION: Water or an aq. soln. of a heavy metal fixing agent is added to a heavy metal-contg. fly ash and heated to 40-200 deg.C. Otherwise, water, cement and a heavy metal filing agent are added to the fly ash and heated to 40-200 deg.C. In thus case, 10-50 parts of water, 0.5-5 parts of the fixing agent and 1-50 parts, preferably 5-25 parts, of cement are added to 100 parts of the fly ash. The heavy metal fixing agent forms a water-insoluble sulfide or chelate together with the heavy metals such as lead, chromium, copper, mercury and nickel in the fly ash, and sodium sulfide, potassium sulfide or a polyamine derivative such as ethyldiamine are exemplified as the agent.

Effect of temperature and water as additive on the MW and thermal properties of copoly(p-phenylene/biphenylene sulfide)s

Abstract: Copoly(p-phenylene/biphenylene sulfide)s, PPBS were prepared from sodium sulfide trihydate(Na 2 S.3H 2 0), p-dichlorobenzene (DCB), and 4,4'-dibromobiphenyl (DBB) comonomers in N-methyl-2-pyrrolidinone (NMP) solvent using an autoclave. The molecular weights of PPBS copolymers were determined by high temperature (210°C) GPC in 1-chloronaphthalene solvent. The reaction temperature had little effect on the molecular weights of PPBS copolymers with water as additive at the level of 3 mol H 2 O per 1 mol Na 2 S. PPBS copolymer, however, showed maximum molecular weight of M w = 24.1 x l0 3 with the total water content of 9 mol H 2 O per 1 mol Na 2 S at an optimum polymerization temperature of 270°C. The resulting PPBS copolymer sample showed higher T g (by 30°C) and lower T m (by 10°C) than PPS homopolymer prepared under similar conditions.

Sulfide as electron source for H2-photoproduction in the cyanobacterium Synechococcus sp., strain Miami BG 043511, under stress conditions

Abstract: Synechococcus sp., strain Miami BG 043511, was used as biological material to examine whether cyanobacteria, like photosynthetic bacteria, can utilize sulfide as electron source for H2 photoproduction. We found that sulfide can have either an inhibiting or a stimulating effect on the H2 production of the cyanobacterium, depending on growth conditions, age and sulfide concentration in the nutrient solution. When sodium sulfide (more than 5 mM) was added, H2 production was inhibited in three-day-old cells. The inhibition was negligible with seven-day-old cells, whereas a stimulating effect was measured with 15-day-old cells in the stationary growth phase. At the latter stage the limited light intensity and the deficiency in nutrients represent extreme stress conditions for the organism. The stimulating effect of sulfide under these stress conditions could be enhanced by increasing sulfide concentrations. The stimulating effect of sulfide on H2 production was further confirmed by administering gradually increasing sulfide concentrations to immobilized cells. Our results suggest that Synechococcus sp. strain Miami BG 043511 is able to use sulfide as electron donor for H2 photoproduction, especially under stress conditions.

Kraf-liquor alkali analysis using near-infrared spectroscopy

Abstract: NIR (near-infrared) spectroscopy was used to measure sodium hydroxide, effective alkali, hydrosulfide ion, and sodium carbonate concentrations in kraft liquor. Measurements were made using a multiple-component liquid process analyzer capable of scanning between 1100-2200 nm. Partial least-squares regression analysis was used to correlate the concentrations of individual components to signal intensities at different wavelengths. The study also investigated the interaction of sodium sulfide on the prediction of sodium sulfide on the prediction accuracy of sodium hydroxide in the liquor. The results show that the spectrometer can be calibrated to measure either the sodium hydroxide or effective-alkali concentration with equal predictive ability. Moreover, the multivariate analysis method developed can determine hydroxide concentration in the presence of Na 2 S and Na 2 CO 2 . The proposed method can be used in on-line process monitoring and control applications. Application : this information provides a method for on-line measurement and control of kraft liquor content.

Fractional recovery of lead and zinc from incinerated ash

Abstract: PURPOSE:To successively precipitate the lead and zinc in an incinerated ash as the sulfides and to fractionally recover the lead and zinc efficiently by supplying sodium sulfide to a soln. containing eluted heavy metals from the ash and regulating the pH of the soln. CONSTITUTION:The incinerated ash of refuse, etc., is mixed with hydrochloric acid to elute the heavy metals from the ash, and solid is separated from liq. to prepare the soln. of the heavy metals. Sodium sulfide or gaseous hydrogen sulfide is supplied while agitating the soln., and the pH is regulated to 0.4-1.2 to precipitate lead as the sulfide, which is separated and recovered. Sodium sulfide or gaseous hydrogen sulfide is then supplied to the soln. separated from the precipitate, and the pH is regulated to >=2 to precipitate the zinc as the sulfide, which is separated and recovered. Consequently, lead and zinc are fractionally separated from the incinerated ash efficiently, and the waste water generated in the recovery is made harmless.

Production of water soluble protein

Abstract: PURPOSE: To readily obtain the subject protein useful as a cosmetic, an additive for foods, a modifying agent for clothes, coatings, etc., by treating a water- insoluble protein raw material with a reducing agent, then treating the treated raw material in an aqueous solution containing an oxidizing agent, subsequently adding an alkali thereto and alkalinizing the liquidity. CONSTITUTION: A water-insoluble protein raw material comprising a feather, an egg, hair, a nail, a horn, skin, meat or a fish scale which is a protein derived from an animal, a silk or a cocoon that is a protein derived from an insect or beans, gluten, rice bran or their processed products, etc., which are proteins derived from a plant is treated with a reducing agent such as sodium sulfide, sodium sulfite, mercaptoethanol, thioglycolic acid, an ammonium salt, a tialkylphosphine or monoethanolamine sulfide, then treated in an aqueous solution containing an oxidizing agent such as hydrogen peroxide, peracetic acid or performic acid and an alkali such as an aqueous ammonia, an aqueous solution of sodium hydroxide or an aqueous solution of sodium carbonate is subsequently added to alkalinize the liquidity. Thereby, the waste liquor treatment is simplified to afford the objective water soluble protein in high yield.

Synthesis of thiol- and carboxyl-terminated poly(p-phenylene sulfide) oligomers

Abstract: Poly(p-phenylene sulfide) (PPS) oligomers were synthesized from sodium sulfide (SS) and p-dichlorobenzene (p-DCB) in hexamethylphosphoramide (HMPA) under atmospheric pressure. The effects of reaction time, temperature, and monomer ratio on end groups and molecular weight of PPS oligomers were investigated. The results show that the molecular weight is controlled by the above parameters. Thiol-terminated PPS oligomers were prepared by two routes. One was the polycondensation of p-DCB with equimolar SS followed by the reaction with an extra amount of SS. The other was the depolymerization of high molecular weight PPS with SS in HMPA. The results show that the second route is the best one for preparation of thiol-terminated PPS oligomers. Carboxyl-terminated PPS telechelic oligomers were produced through the reaction of thiol-terminated PPS oligomers with p-chlorobenzoic acid.

Solubility of anthraquinone in alkaline solutions of sodium sulfide

Abstract: The reduction of anthraquinone (AQ) with alkaline solutions of sodium sulfide, which takes place in the kraft pulping process, has been studied. The reduction product is the disodium salt of 9,10-dihydroxyanthracene (Na2AQ). A 24 factorial design has been used to check the effects of sodium sulfide, anthraquinone and sodium hydroxide concentrations and temperature on the reaction. From statistical results, it has been concluded that the concentration of reducing agent has a limiting effect on Na2AQ yield, while the temperature has a negative effect because it favours the oxidation of sodium sulfide in alkaline solutions. Therefore, a maximum reduction of quinone can be obtained with the highest concentration of reagents and low temperatures.

The effect of solvents and polyethylene glycol on the synthesis of linear and cyclic poly(methylene sulfide)

Abstract: The condensation polymerization of sodium sulfide with methylene chloride in various solvents was studied in order to assess the influence of polarity on the yield and composition of condensation products. The effect of addition of polyethylene glycol was also studied. It has been found that the overall yield of polythiomethylenes rises from 13.9% in methanol to 85.2% (methanol, PEG15000). The use of solvents of higher polarity promotes the linear oligomers, whereas in methanol the cyclic products predominate. In presence of PEG the this equilibrium is shifted towards tetrathiane. The observed phenomena are discussed in terms of solvents polarity and reaction media viscosity.

Chapter 3 – Sulfide Polymers

Abstract: Publisher Summary This chapter discusses sulfide polymers based on the polysulfides derived from the reaction of dihalides and sodium di- or polysulfides; polyphenylene sulfides generated from aryl dihalides and sodium sulfide; and polyalkylene sulfides generated from ethylene episulfide or dimercaptan-olefin or diolefin-diketone reactions. The sulfide polymers are used because of their resistance to oils and solvents, and they are used as specialty plastics or as gaskets, hoses, printing rolls, etc. Polymers based on ethylene sulfide have not been developed into commercial products yet. Polysulfides are used in synthetic rubber compositions, epoxy resin modifiers, coatings, adhesives, sealants, and many other products. The poly(alkylene sulfides) can be deodorized by treatment with aqueous acetaldehyde. Poly(propylene sulfide) has also found applications in the photo and radiation sensitive resins for use in resists. The thermal properties of poly(ethylene sulfide) and poly(isobutylene sulfide) and copolymers are reported via differential scanning calorimetry.

Method for treating material containing mercury

Abstract: PURPOSE: To prevent mercury vapor from diffusing into exhaust gas by a method in which ash containing mercury is added with water, divalent iron, a pH adjusting agent, and sulfide in sequence, and the mixture is heated with stirring CONSTITUTION: Heavy metals in waste are dissolved in water by adding water for kneading The wet mixture 3 is added with acid and divalent iron, and after pH is adjusted at 70-115, the temperature is kept at 50-95 degC so that the divalent iron in the mixture 3 is crystallized gradually into ferrite In the course of the formation of the crystal lattice of ferrite, heavy metals are taken into the position in place of iron to be fixed Since mercury (Hg ), among heavy metals, is not incorporated into ferrite, the mixture 3, after pH is adjusted at 70-115, is added with sulfide (sodium sulfide, iron sulfide) to react with mercury, and the mercury is fixed in the form of mercury sulfide (HgS)

Physiolosical activator for fishes, and feed additive for pisciculture

Abstract: PURPOSE: To obtain the subject readily mass producible additive, containing green sulfur bacteria as an active ingredient, capable of manifesting effectivenesses such as improvements in body color and yield, and excellent in economical efficiency and the efficiency in adding to the feeds, and without having any evasion of feed ingestion and toxicity. CONSTITUTION: This feed additive contains green sulfur bacteria as an active ingredient [preferably, bacteria of the genus Chlorobiaceae such as Chlorobium limicola (DSM 245)]. The amount of the green sulfur bacteria added to a feed for rearing fishes may be small and sufficient at 0.1%, and in the case of a culturing solution, 1-5% is preferable. Furthermore, culturing of the green sulfur bacteria is preferably performed by using a medium containing somewhat higher concentrations of sodium sulfide and sodium thiosulfate than those in the medium for red sulfur bacteria, and containing 0.05% sodium acetate added as an organic substance, at pH 7.5-6.3 under an irradiation of light at an illuminance so as to provide >=2000 luxes luminous intensity on the surface of culturing vessels at 20-30 deg.C and under completely anaerobic conditions.

Chapter 28 – Polysulfides

Abstract: Publisher Summary This chapter provides an overview of polysulfides; whether aliphatic or aromatic, have excellent physical and chemical properties, which make them one of the leaders in petrochemical industries as elastomers and engineering thermoplastics. Both types are synthesized by a nucleophilic substitution reaction between a dihalide and sodium sulfide. The number of sulfur atoms incorporated into the polysulfide chains differs and depends on the particular reaction system. Aliphatic polysulfides, commonly known as polysulfide rubbers (thiokols), are commercially produced by the nucleophilic substitution polymerization of an aliphatic dihalide with aqueous sodium sulfide of the type Na2Sx. The synthesis of aromatic polysulfides dates back to the late 19th century when a number of chemists described the preparation of these polymeric materials from benzene and sulfur compounds using electrophilic and nucleophilic substitution reactions.

Process for preparing polyphenylen sulfides

Abstract: The polyphenylene sulfide of high Mw is prepared by (a) dissolving sodium sulfide in NMP in a dissolving tank(1) of 80-130deg.C; (b) removing 1.5-3.0M of crystal water within Na2S based on 1M Na2S from the 1st dehydrator(2) equipped with distillation tower(7) at 180-210deg.C and 1atm. for 1-2hrs.; (c) firstly synthesizing prepolymer from obtd. Na2S from (b) and melted p-dichlorobenzene in the 1st polymn. tank(3) equipped with melting tank(10) at 240-260deg.C and 7-15 atm. for 1-2hrs.; (d)completely removing remaining crystal water within prepolymer in the second dehydrator(4) at 200-220deg.C and 1atm. for 1-2hrs.; (e) continuously polymerizing obtd. cpd.. from (d) in the 2nd and 3rd polymn. tank(B,6) at 240-260deg.C and 7-13atm for 1-2hrs.