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Sample records for allyl sulfides studies

  1. A Comparative 90 Day Toxicity Study of Allyl Acetate, Allyl Alcohol and Acrolein

    OpenAIRE

    Auerbach, Scott S.; Mahler, Joel; Travlos, Gregory S.; Irwin, Richard D

    2008-01-01

    Allyl acetate (AAC), allyl alcohol (AAL), and acrolein (ACR) are used in the manufacture of detergents, plastics, pharmaceuticals, and chemicals and as agricultural agents. A metabolic relationship exists between these chemicals in which allyl acetate is metabolized to allyl alcohol and subsequently to the highly reactive,α,β-unsaturated aldehyde, acrolein. Due to the weaker reactivity of the protoxicants, allyl acetate and allyl alcohol, relative to acrolien we hypothesized the protoxicants ...

  2. STUDY OF HYDROGEN SULFIDE REMOVAL FROM GROUNDWATER

    Directory of Open Access Journals (Sweden)

    T. Lupascu

    2013-06-01

    Full Text Available The process of the hydrogen sulfide removal from the underground water of the Hancesti town has been investigated. By oxygen bubbling through the water containing hydrogen sulfide, from the Hancesti well tube, sulfur is deposited in the porous structure of studied catalysts, which decreases their catalytic activity. Concomitantly, the process of adsorption / oxidation of hydrogen sulfide to sulfate take place. The kinetic research of the hydrogen sulfide removal from the Hancesti underground water, after its treatment by hydrogen peroxide, proves greater efficiency than in the case of modified carbonic adsorbents. As a result of used treatment, hydrogen sulfide is completely oxidized to sulfates

  3. Isolation determination of garlic allyl sulfides and their antioxidant activity%大蒜烯丙基硫化物的分离鉴定及抗氧化性

    Institute of Scientific and Technical Information of China (English)

    刘玲; 陈琭璐; 张瑶; 白冰; 纪淑娟

    2015-01-01

    为了研究大蒜烯丙基硫化物的抗氧化活性,该文利用离子交换层析与制备液相技术从大蒜中分离得到 S-烯丙基-L-半胱氨酸(S-allyl-L-cysteine,SAC)、S-烯丙基-L-半胱氨酸亚砜(S-allyl-L-cysteine sulfoxide,ACSO)和γ-谷氨酰-S-烯丙基-L-半胱氨酸(γ-L-glutamyl-S-allyl-L-cysteine,GSAC)3种水溶性烯丙基硫化物。分离产物利用高效液相色谱-电喷雾离子化串联质谱联用(high performance liquid chromatography-electrospray ionization-mass/mass spectrometry, HPLC-ESI-MS/MS)、核磁共振氢谱(proton nuclear magnetic resonance,1H NMR)和核磁共振碳谱(carbon-13 nuclear magnetic resonance,13C NMR)技术及比旋光度检测方法鉴定,并与合成标准品比对分析确定。同时,该文以具有半胱氨酸结构的还原型谷胱甘肽(glutathione,GSH)为参照测定了 SAC、ACSO、GSAC 的1,1-二苯基-2-三硝基苯肼(1,1-diphenyl-2-picrylhydrazyl,DPPH)自由基清除能力及铁离子螯合能力。结果表明,SAC和GSAC对DPPH自由基的清除率较高(73.55%,72.68%)且与 GSH(71.14%)无显著性差异(P<0.05);SAC 和 ACSO 对铁离子的螯合率较高(81.21%,79.18%)且与GSH(78.13%)无显著性差异(P<0.05),尤其是GSAC对铁离子螯合率(92.76%)显著性高于GSH(P<0.05),证实了3种硫化物均具有很好的抗氧化性能。研究结果进一步解释和阐述大蒜硫化物的螯合能力,进而为大蒜硫化物以抗氧化为基础的其他功能活性研究提供参考。%The allyl-substituted cysteine derivatives were major components of sulfur compounds in garlic. This study separated and identified 3 allyl-substituted cysteine derivatives, i.e.S-allyl-L-cysteine (SAC),S-allyl-L-cysteine sulfoxide (ACSO) andγ-L-glutamyl-S-allyl-L-cysteine (GSAC). Furthermore, scavenging ability of 1,1-Diphenyl-2-picrylhydrazyl (DPPH) free radical and iron chelating ability were tested

  4. Kinetic Studies that Evaluate the Solvolytic Mechanisms of Allyl and Vinyl Chloroformate Esters

    Directory of Open Access Journals (Sweden)

    Malcolm J. D'Souza

    2013-04-01

    Full Text Available At 25.0 °C the specific rates of solvolysis for allyl and vinyl chloroformates have been determined in a wide mix of pure and aqueous organic mixtures. In all the solvents studied, vinyl chloroformate was found to react significantly faster than allyl chloroformate. Multiple correlation analyses of these rates are completed using the extended (two-term Grunwald-Winstein equation with incorporation of literature values for solvent nucleophilicity (NT and solvent ionizing power (YCl. Both substrates were found to solvolyze by similar dual bimolecular carbonyl-addition and unimolecular ionization channels, each heavily dependent upon the solvents nucleophilicity and ionizing ability.

  5. Structural studies in limestone sulfidation

    Energy Technology Data Exchange (ETDEWEB)

    Fenouil, L.A.; Lynn, S.

    1993-05-01

    This study investigates the sulfidation of limestone at high temperatures (700--900{degree}C) as the first step in the design of a High-Temperature Coal-Gas Clean-Up system using millimeter-size limestone particles. Several workers have found that the rate of this reaction significantly decreases after an initial 10 to 15% conversion of CaCO{sub 3} to CaS. The present work attempts to explain this feature. It is first established that millimeter-size limestone particles do not sinter at temperatures up to the CaCO{sub 3} calcination point (899{degree}C at 1.03 bar CO{sub 2} partial pressure). It is then shown that CaS sinters rapidly at 750 to 900{degree}C if CO{sub 2} is present in the gas phase. Scanning Electron Microscope (SEM) photographs and Electron Dispersive Spectroscopy (EDS) data reveal that the CaS product layer sinters and forms a quasi-impermeable coating around the CaCO{sub 3} grains that greatly hinders more H{sub 2}S from reaching the still unreacted parts of the stone. Moreover, most of the pores initially present within the limestone structure begin to disappear or, at least, are significantly reduced in size. From then on, subsequent conversion is limited by diffusion of H{sub 2}S through the CaS layer, possibly by S{sup 2{minus}} ionic diffusion. The kinetics is then adequately described by a shrinking-core model, in which a sharp front of completely converted limestone is assumed to progress toward the center of the pellet. Finally, experimental evidence and computer simulations using simple sintering models suggest that the CaS sintering, responsible for the sharp decrease in the sulfidation rate, is surface-diffusion controlled.

  6. The allylic chalcogen effect in olefin metathesis

    Directory of Open Access Journals (Sweden)

    Yuya A. Lin

    2010-12-01

    Full Text Available Olefin metathesis has emerged as a powerful tool in organic synthesis. The activating effect of an allylic hydroxy group in metathesis has been known for more than 10 years, and many organic chemists have taken advantage of this positive influence for efficient synthesis of natural products. Recently, the discovery of the rate enhancement by allyl sulfides in aqueous cross-metathesis has allowed the first examples of such a reaction on proteins. This led to a new benchmark in substrate complexity for cross-metathesis and expanded the potential of olefin metathesis for other applications in chemical biology. The enhanced reactivity of allyl sulfide, along with earlier reports of a similar effect by allylic hydroxy groups, suggests that allyl chalcogens generally play an important role in modulating the rate of olefin metathesis. In this review, we discuss the effect of allylic chalcogens in olefin metathesis and highlight its most recent applications in synthetic chemistry and protein modifications.

  7. Experimental and Kinetic Modeling Study of 2-Methyl-2-Butene: Allylic Hydrocarbon Kinetics.

    Science.gov (United States)

    Westbrook, Charles K; Pitz, William J; Mehl, Marco; Glaude, Pierre-Alexandre; Herbinet, Olivier; Bax, Sarah; Battin-Leclerc, Frederique; Mathieu, Olivier; Petersen, Eric L; Bugler, John; Curran, Henry J

    2015-07-16

    Two experimental studies have been carried out on the oxidation of 2-methyl-2-butene, one measuring ignition delay times behind reflected shock waves in a stainless steel shock tube, and the other measuring fuel, intermediate, and product species mole fractions in a jet-stirred reactor (JSR). The shock tube ignition experiments were carried out at three different pressures, approximately 1.7, 11.2, and 31 atm, and at each pressure, fuel-lean (ϕ = 0.5), stoichiometric (ϕ = 1.0), and fuel-rich (ϕ = 2.0) mixtures were examined, with each fuel/oxygen mixture diluted in 99% Ar, for initial postshock temperatures between 1330 and 1730 K. The JSR experiments were performed at nearly atmospheric pressure (800 Torr), with stoichiometric fuel/oxygen mixtures with 0.01 mole fraction of 2M2B fuel, a residence time in the reactor of 1.5 s, and mole fractions of 36 different chemical species were measured over a temperature range from 600 to 1150 K. These JSR experiments represent the first such study reporting detailed species measurements for an unsaturated, branched hydrocarbon fuel larger than iso-butene. A detailed chemical kinetic reaction mechanism was developed to study the important reaction pathways in these experiments, with particular attention on the role played by allylic C-H bonds and allylic pentenyl radicals. The results show that, at high temperatures, this olefinic fuel reacts rapidly, similar to related alkane fuels, but the pronounced thermal stability of the allylic pentenyl species inhibits low temperature reactivity, so 2M2B does not produce "cool flames" or negative temperature coefficient behavior. The connections between olefin hydrocarbon fuels, resulting allylic fuel radicals, the resulting lack of low-temperature reactivity, and the gasoline engine concept of octane sensitivity are discussed. PMID:25822578

  8. Neutron response study using poly allyl diglycol carbonate

    Indian Academy of Sciences (India)

    Basma A El-Badry; M F Zaki; Tarek M Hegazy; A Ahmed Morsy

    2007-10-01

    The results of an experimental work aimed at improving the performance of the CR-39 nuclear track detector for neutron dosimetry applications are reported. A set of CR-39 plastic detectors was exposed to 252Cf neutron source, which has the emission rate of 0.68 × 108 s-1, and neutron dose equivalent rate 1 m apart from the source is equal to 3.8 mrem/h. The detection of fast neutrons performed with CR-39 detector foils, subsequent chemical etching and evaluation of the etched tracks by an automatic track counting system was studied. It is found that the track density increases with the increase of neutron dose and etching time. The track density in the detector is directly proportional to the neutron fluence producing the recoil tracks, provided the track density is in the countable range. This fact plays an important role in determining the equivalent dose in the field of neutron dosimetry. These results are compared with previous work. It is found that our results are in good agreement with their investigations.

  9. Study on the sulfidation behavior of smithsonite

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Dandan; Wen, Shuming, E-mail: shmwen@126.com; Deng, Jiushuai, E-mail: dengshuai689@163.com; Liu, Jian; Mao, Yingbo

    2015-02-28

    Highlights: • Zeta potential showed that the pH{sub IEP} of smithsonite decreased from 7.7 to 6. • ICP test showed the gradual reduction of C{sub S} in the solution. • SEM showed that the mineral surface was partially changed to ZnS film. • XPS indicated that the presence of a characteristic signal peak of sulfur ions. - Abstract: Zinc extraction from low-grade mineral resources of oxidized zinc has recently become a focus of study. Sulfidation is an important process in oxidized ore flotation. In this study, the influence of sulfur ion adsorption on smithsonite surface was investigated with the use of zeta potential, inductively coupled plasma (ICP), scanning electron microscope (SEM), and X-ray photoelectron spectroscopic studies. Zeta potential measurements of sodium sulfide showed that sulfur ions were adsorbed onto the surface of pure smithsonite, as evidenced by the increased negative charge and the decrease in the pH{sub IEP} of smithsonite from 7.7 to 6 after sodium sulfide treatment. The ICP test revealed the gradual reduction in sulfur ion adsorption onto the surface of smithsonite in pulp sulfur. After 30 min of absorption, C{sub S} in the solution declined from 1000 × 10{sup −6} mol/L to 1.4 × 10{sup −6} mol/L. SEM results showed that the mineral surface was partially changed to ZnS film after sodium sulfide treatment, whereas EDS analysis results showed that 2% S is contained on the smithsonite surface. X-ray photoelectron spectroscopy results indicated the presence of a characteristic signal peak of sulfur ions after sulfidation. Sulfur concentration increased to 11.89%, whereas oxygen concentration decreased from 42.31% to 13.74%. Sulfur ions were not only present during chemical adsorption, but were also incorporated into the crystal lattices of minerals by the exchange reaction between S{sup 2−} and CO{sub 3}{sup 2−} ions.

  10. Interplay of metal-allyl and metal-metal bonding in dimolybdenum allyl complexes.

    Energy Technology Data Exchange (ETDEWEB)

    Trovitch, R. J.; John, K. D.; Martin, R. L.; Obrey, S. J.; Sattelberger, A. P.; Scott, B. L.; Baker, R. T.; LANL; Univ. of Ottawa

    2009-01-01

    Addition of PMe{sub 3} to Mo{sub 2}(allyl){sub 4} afforded Mo{sub 2}(allyl){sub 4}(PMe{sub 3}){sub 2}, in which two of the allyl groups adopt an unprecedented {mu}{sub 2}-{eta}{sup 1}, {eta}{sup 3} bonding mode; theoretical studies elucidate the roles of the {sigma}- and {pi}-donor ligands in the interplay of metal-allyl and metal-metal bonding.

  11. β-Elimination of an Aziridine to an Allylic Amine: A Mechanistic Study

    OpenAIRE

    Morgan, Kathleen M.; Brown, Garry; Pichon, Monique A.; Green, Geannette Y.

    2011-01-01

    The base-induced rearrangement of aziridines has been examined using a combination of calculations and experiment. The calculations show that the substituent on nitrogen is a critical feature that greatly affects the favorability of both α-deprotonation, and β-elimination to form an allylic amine. Experiments were carried out to determine whether E2-like rearrangement to the allylic amine with lithium diisopropyl amide (LDA) is possible. N-Tosyl aziridines were found to deprotonate on the tos...

  12. Synthetic Studies on Tricyclic Diterpenoids: Direct Allylic Amination Reaction of Isopimaric Acid Derivatives.

    Science.gov (United States)

    Timoshenko, Mariya A; Kharitonov, Yurii V; Shakirov, Makhmut M; Bagryanskaya, Irina Yu; Shults, Elvira E

    2016-02-01

    A selective synthesis of 7- or 14-nitrogen containing tricyclic diterpenoids was completed according to a strategy in which the key step was the catalyzed direct allylic amination of methyl 14α-hydroxy-15,16-dihydroisopimarate with a wide variety of nitrogenated nucleophiles. It was revealed that the selectivity of the reaction depends on the nature of nucleophile. The catalyzed reaction of the mentioned diterpenoid allylic alcohol with 3-nitroaniline, 3-(trifluoromethyl)aniline, and 4-(trifluoromethyl)aniline yield the subsequent 7α-, 7β- and 14αnitrogen-containing diterpenoids. The reaction with 2-nitroaniline, 4-nitro-2-chloroaniline, 4-methoxy-2-nitroaniline, phenylsulfamide, or tert-butyl carbamate proceeds with the formation of 7α-nitrogen-substituted diterpenoids as the main products. PMID:27308214

  13. An XPS study of pulsed plasma polymerised allyl alcohol film growth on polyurethane

    International Nuclear Information System (INIS)

    The growth of highly functionalised poly allyl alcohol films by pulsed plasma polymerisation of CH2 =CHCH2OH on biomedical grade polyurethane has been followed by X-ray photoelectron spectroscopy (XPS) and contact angle measurements. Film thickness is observed to increase approximately linearly with plasma modification time, suggesting a layer-by-layer growth mode of poly allyl alcohol. Water contact angle measurements reveal the change in the surface free energy of wetting decreases linearly with plasma modification up to the monolayer point after which a constant limiting value of -24 mJ m-2 was attained. Films prepared at 20 W plasma power with a duty cycle of 10 μs:500 μs exhibit a high degree of hydroxyl (-OH) retention with minimal fragmentation of the monomer observed. Increasing the plasma power up to 125 W is found to improve -OH retention at the expense of ether formation generating films close to the monomer stoichiometry. Duty cycle plays an important role in controlling both film composition and thickness, with longer off times increasing -OH retention, while longer on times enhance allyl alcohol film growth

  14. Theoretical study on the gas phase reaction of allyl chloride with hydroxyl radical.

    Science.gov (United States)

    Zhang, Yunju; Chao, Kai; Sun, Jingyu; Zhang, Wanqiao; Shi, Haijie; Yao, Cen; Su, Zhongmin; Pan, Xiumei; Zhang, Jingping; Wang, Rongshun

    2014-02-28

    The reaction of allyl chloride with the hydroxyl radical has been investigated on a sound theoretical basis. This is the first time to gain a conclusive insight into the reaction mechanism and kinetics for important pathways in detail. The reaction mechanism confirms that OH addition to the C=C double bond forms the chemically activated adducts, IM1 (CH2CHOHCH2Cl) and IM2 (CH2OHCHCH2Cl) via low barriers, and direct H-abstraction paths may also occur. Variational transition state model and multichannel RRKM theory are employed to calculate the temperature-, pressure-dependent rate constants. The calculated rate constants are in good agreement with the experimental data. At 100 Torr with He as bath gas, IM6 formed by collisional stabilization is the major products in the temperature range 200-600 K; the production of CH2CHCHCl via hydrogen abstractions becomes dominant at high temperatures (600-3000 K). PMID:24588171

  15. Kinetic studies of cadmium sulfide precipitation from aqueous thiourea solutions

    International Nuclear Information System (INIS)

    Kinetics of cadmium sulfide precipitation by thiourea from aqueous solutions containing ammonia complexes of cadmium(II) under conditions of spontaneous initiation of solid phase within solution volume at temperatures of 298-318 K was studied. It was ascertained that the process activation energy is 77843 J/mol, while the reaction order by initial cadmium complex equals unity. Kinetic equation, which permits control over cadmium sulfide precipitation and preparation of CdS films of desired morphology was derived on the basis of the experimental data

  16. Kinetic Studies of Sulfide Mineral Oxidation and Xanthate Adsorption

    OpenAIRE

    Mendiratta, Neeraj K.

    2000-01-01

    Sulfide minerals are a major source of metals; however, certain sulfide minerals, such as pyrite and pyrrhotite, are less desirable. Froth flotation is a commonly used separation technique, which requires the use of several reagents to float and depress different sulfide minerals. Xanthate, a thiol collector, has gained immense usage in sulfide minerals flotation. However, some sulfides are naturally hydrophobic and may float without a collector. Iron sulfides, such as pyrite and pyrrho...

  17. Morphology and thermal studies of zinc sulfide and cadmium sulfide nanoparticles in polyvinyl alcohol matrix

    Science.gov (United States)

    Osuntokun, Jejenija; Ajibade, Peter A.

    2016-09-01

    Zn(II) and Cd(II) metal complexes of 1-cyano-1-carboethoxyethylene-2,2-dithiolato-κS,S'-bis(N,N-dimethylthiourea-κS) have been synthesized and characterized with analytical and spectroscopic techniques. The complexes were thermolysed in hexadecylamine at 200 °C to prepare ZnS and CdS nanoparticles. The nanoparticles were characterized with scanning electron microscope (SEM), transmission electron microscope (TEM), and powder X-ray diffraction (p-XRD). TEM images showed spherically shaped nanoparticles, whose sizes are in the range 4.33-7.21 nm for ZnS and 4.95-7.7 nm CdS respectively and XRD confirmed cubic crystalline phases for the nanoparticles. The optical band gap energy evaluated from the absorption spectra are 2.88 eV (430 nm) and 2.81 eV (440 nm) for the ZnS and CdS nanoparticles respectively. The as-prepared metal sulfide nanoparticles were further incorporated into polyvinyl alcohol (PVA) to give ZnS/PVA and CdS/PVA composites. The polymer nanocomposites were studied to investigate their morphology and thermal properties relative to the pure PVA. XRD diffractions indicated that the crystalline phases of the nanoparticles and the sizes in PVA matrices remained unaltered. Infra-red spectra studies revealed interactions between the PVA and the metal sulfide nanoparticles and TGA studies show that the ZnS/PVA and CdS/PVA nanocomposites exhibit better thermal stability than the pure PVA.

  18. Study of preparation of radioiodinated allyl diprenorphine as an single photon emission computed tomographic imaging agent for mapping opioid receptors

    International Nuclear Information System (INIS)

    Purpose: To prepare and evaluate radioiodinated allyl diprenorphine (DPN) as a new opioid receptor imaging agent for SPECT study. Methods: 7α-O-stannyl-DPN was obtained from DPN by acetylated it to protect the phenolic 3-OH group of DPN and then introduced the vinylstannane into the tertiary alcohol of the 7α-side chain. [125I]-7α-O-iodoallyl diprenorphine (7α-O-IA-DPN) was prepared by radioiododestannylation under acidic condition using iodobead as an oxidant reagent, and in vitro and in vivo opioid receptor binding assays, metabolism were performed with Kunming mouse brains. Study of distribution in the Wistar rat's brain and naloxone inhibition was carried out. The data were analyzed by statistical method. Results: The radiochemical yields of I-125-7α-O-IA-DPN were more than 90%. In TLC, Rf of 7α-O-IA-DPN and I-125-7α-O-IA-DPN was 0.83 and 0.93, respectively. In ambient temperature the radiochemical purity of I-125-7α-O-IA-DPN in rats showed higher in anterior and posterior colliculi, striatum and hippocampus. It was low in frontal lobe, temporal lobe and brain stem and was low in cerebellum and the other parts of the brain. Among the clearance from the structures in brain, it was fastest in cerebellum. At 20 min when the uptake reached to the peak, the ratio of anterior and posterior colliculi, striatum and hippocampus to the cerebellum was 4.36, 3.7 and 3.12, respectively. There were significant differences between the inhibition experimental group using the naloxone and control. Conclusions: I-125-7α-O-IA-DPN appears to be a potential opioid receptor imaging agent for SPECT study. (authors)

  19. Relationships of isomerization of the allylic type

    Energy Technology Data Exchange (ETDEWEB)

    Levanova, S.V.; Yanshevskaya, I.V.; Asatryan, E.M.; Saakyan, N.L.; Kostand' yan, V.A.; Malkhasyan, A.Ts.; Martirosyan, G.T.

    1986-10-10

    The authors report the results of thermodynamic and kinetic studies of allylic rearrangement of dichlorobutenes. Allylic rearrangements were studied in a thermo-stated glass flask fitted with a stirrer, with the use of various (with respect to total DCB) original mixtures of the three isomers. A solution of copper naphthenate in solvent naphtha, containing 5% Cu, was used as the catalyst. The reaction mixture was analyzed periodically with the aid of the LKhM-8MD chromatograph, using a column 3000 x 3 mm packed with 5% of Apiezone and 5% of polyethylene glycol on Chromosorb W. The operating temperature was 120/sup 0/.

  20. Synthesis and uranyl ion adsorption study of cross-linked allyl propionate-maleic anhydride-styrene terpolymer

    OpenAIRE

    AKPEROV, Elchin; MAHARRAMOV, Abel; AKPEROV, Oktay

    2010-01-01

    Allyl propionate-maleic anhydride-styren terpolymer has been modified with glycerin in order to prepare a new cross-linked functional polymer sorbent. The synthesized cross-linked polymer sorbent has a network structure and contains carboxylic acid, carbonyl, hydroxy, and ester groups, all of which are capable ofinteracting with metal ions. The sorption behavior of UO22+ ions under optimum sorption conditions was determined. The sorption properties of the sorbent were determined unde...

  1. The removal of hydrogen sulfide from gas streams using an aqueous metal sulfate absorbent : Part II. the regeneration of copper sulfide to copper oxide - An experimental study

    NARCIS (Netherlands)

    Ter Maat, H.; Hogendoorn, J. A.; Versteeg, G. F.

    2005-01-01

    Aim of this study was to investigate the possibilities for a selective and efficient method to convert copper(II) sulfide (CuS) into copper(II) oxide (CuO). The oxidation of copper sulfide has been studied experimentally using a thermogravimetric analyzer (TGA) at temperatures ranging from 450 to 75

  2. Transition state region in the A-Band photodissociation of allyl iodide—A femtosecond extreme ultraviolet transient absorption study

    Science.gov (United States)

    Bhattacherjee, Aditi; Attar, Andrew R.; Leone, Stephen R.

    2016-03-01

    Femtosecond extreme ultraviolet (XUV) transient absorption spectroscopy based on a high-harmonic generation source is used to study the 266 nm induced A-band photodissociation dynamics of allyl iodide (CH2 =CHCH2I). The photolysis of the C—I bond at this wavelength produces iodine atoms both in the ground (2P3/2, I) and spin-orbit excited (2P1/2, I*) states, with the latter as the predominant channel. Using XUV absorption at the iodine N4/5 edge (45-60 eV), the experiments constitute a direct probe of not only the long-lived atomic iodine reaction products but also the fleeting transition state region of the repulsive nIσ∗C—I excited states. Specifically, three distinct features are identified in the XUV transient absorption spectrum at 45.3 eV, 47.4 eV, and 48.4 eV (denoted transients A, B, and C, respectively), which arise from the repulsive valence-excited nσ∗ states and project onto the high-lying core-excited states of the dissociating molecule via excitation of 4d(I) core electrons. Transients A and B originate from 4d(I) → n(I) core-to-valence transitions, whereas transient C is best assigned to a 4d(I) →σ∗(C—I) transition. The measured differential absorbance of these new features along with the I/I* branching ratios known from the literature is used to suggest a more definitive assignment, albeit provisional, of the transients to specific dissociative states within the A-band manifold. The transients are found to peak around 55 fs-65 fs and decay completely by 145 fs-185 fs, demonstrating the ability of XUV spectroscopy to map the evolution of reactants into products in real time. The similarity in the energies of transients A and B with analogous features observed in methyl iodide [Attar et al. J. Phys. Chem. Lett. 6, 5072, (2015)] together with the new observation of transient C in the present work provides a more complete picture of the valence electronic structure in the transition state region. The results provide a benchmark for

  3. Mild and Site-Selective Allylation of Enol Carbamates with Allylic Carbonates under Rhodium Catalysis.

    Science.gov (United States)

    Sharma, Satyasheel; Han, Sang Hoon; Oh, Yongguk; Mishra, Neeraj Kumar; Han, Sangil; Kwak, Jong Hwan; Lee, Seok-Yong; Jung, Young Hoon; Kim, In Su

    2016-03-18

    The rhodium(III)-catalyzed mild and site-selective C-H allylation of enol carbamates with 4-vinyl-1,3-dioxolan-2-one and allylic carbonates affords allylic alcohols and terminal allylated products, respectively. The assistance of the carbamoyl directing group provides a straightforward preparation of biologically and synthetically important allylated enol carbamates. PMID:26906724

  4. Why does the Conductivity of a Nickel Catalyst Increase during Sulfidation? An Exemplary Study Using an In Operando Sensor Device

    OpenAIRE

    Peter Fremerey; Andreas Jess; Ralf Moos

    2015-01-01

    In order to study the sulfidation of a catalyst fixed bed, an in operando single pellet sensor was designed. A catalyst pellet from the fixed bed was electrically contacted and its electrical response was correlated with the catalyst behavior. For the sulfidation tests, a nickel catalyst was used and was sulfidized with H2S. This catalyst had a very low conductivity in the reduced state. During sulfidation, the conductivity of the catalyst increased by decades. A reaction from nickel to nicke...

  5. Study of crystallization behavior of poly(phenylene sulfide

    Directory of Open Access Journals (Sweden)

    Liliana B. Nohara

    2006-06-01

    Full Text Available Poly(phenylene sulfide (PPS is an engineering thermoplastic polymer that presents high temperature resistance (glass transition temperature around 85 ºC and melting point at 285 ºC. These properties combined with its mechanical properties and its high chemical resistance allows its use in technological applications such as molding resins and as matrix for structural thermoplastic composites. During the manufacture of thermoplastic composites, the polymer is exposed to repeated melting, quenching and crystallization processes. The properties of semicrystalline polymers, such as PPS, depend on its crystallization behavior. This work deals with the PPS crystallization kinetics under different thermal cycles. This study was performed under isothermal conditions in a differential scanning calorimetry (DSC, coupled to Perkin Elmer crystallization software referred to as Pyris Kinetics - Crystallization. The results were correlated with microscopic analyses carried out in a polarized light microscope, equipped with a controlled heating and cooling accessory. In this case, the experimental conditions were the same adopted for the DSC analyses. From the results, parameters could be established to be used in the composite manufacture.

  6. Using a portable sulfide monitor as a motivational tool: A clinical study

    OpenAIRE

    Ranjit Singh Uppal; Ranjan Malhotra; Vishakha Grover; Deepak Grover

    2012-01-01

    Aims and Objectives: Bad breath has a significant impact on daily life of those who suffer from it. Oral malodor may rank only behind dental caries and periodontal disease as the cause of patient′s visit to dentist. An aim of this study was to use a portable sulfide monitor as a motivational tool for encouraging the patients towards the better oral hygiene by correlating the plaque scores with sulfide monitor scores, and comparing the sulfide monitor scores before and after complete prophylax...

  7. Velocity Map Imaging Study of Ion-Radical Chemistry: Charge Transfer and Carbon-Carbon Bond Formation in the Reactions of Allyl Radicals with C(.).

    Science.gov (United States)

    Pei, Linsen; Farrar, James M

    2016-08-11

    We present an experimental and computational study of the dynamics of collisions of ground state carbon cations with allyl radicals, C3H5, at a collision energy of 2.2 eV. Charge transfer to produce the allyl cation, C3H5(+), is exoergic by 3.08 eV and proceeds via energy resonance such that the electron transfer occurs without a significant change in nuclear velocities. The products have sufficient energy to undergo the dissociation process C3H5(+) → C3H4(+) + H. Approximately 80% of the reaction products are ascribed to charge transfer, with ∼40% of those products decaying via loss of a hydrogen atom. We also observe products arising from the formation of new carbon-carbon bonds. The experimental velocity space flux distributions for the four-carbon products are symmetric about the centroid of the reactants, providing direct evidence that the products are mediated by formation of a C4H5(+) complex living at least a few rotational periods. The primary four-carbon reaction products are formed by elimination of molecular hydrogen from the C4H5(+) complex. More than 75% of the nascent C4H3(+) products decay by C-H bond cleavage to yield a C4H2(+) species. Quantum chemical calculations at the MP2/6-311+g(d,p) level of theory support the formation of a nonplanar cyclic C4H5(+) adduct that is produced when the p-orbital containing the unpaired electron on C(+) overlaps with the unpaired spin density on the terminal carbon atoms in allyl. Product formation then occurs by 1,2-elimination of molecular hydrogen from the cyclic intermediate to form a planar cyclic C4H3(+) product. The large rearrangement in geometry as the C4H3(+) products are formed is consistent with high vibrational excitation in that product and supports the observation that the majority of those products decay to form the C4H2(+) species. PMID:27434380

  8. Molecular Simulation Study on Interaction of Thiophene Sulfides with Transition Metals

    Institute of Scientific and Technical Information of China (English)

    Liu Yujian; Long Jun; Zhou Han; Zhu Yuxia; Da Zhijian

    2003-01-01

    The computer molecular simulation technique was applied to study the chemisorption of thiophene and tetramethylthiophene as the model sulfides on the simple oxides and complex oxides of some transition metals as the catalytic materials. The study disclosed that the thiophene sulfides could enter into chemisorption with metal oxides such as VO, ZnO, NiO and Zn-Al-spinel. This interaction could lead to thiophene molecular structure deformation to be in an activated adsorption state, which could help to promote the conversion of thiophene sulfides in the course of catalytic cracking. The VO with a valence of 2 could provide relatively strong selective adsorption sites for the conversion of thiophene sulfides to apparently transform the molecular structures and electron cloud states of such heterocyclic sulfur compounds such as thiophene and tetramethylthiophene into an activated adsorption state. The effect of this interaction was more pronounced with respect to tetramethylthiophene.

  9. Genesis of new gas oil HDS catalysts. Study of their liquid phase sulfidation

    Energy Technology Data Exchange (ETDEWEB)

    Frizi, Naima; Blanchard, Pascal; Payen, Edmond; Baranek, Pascale; Lancelot, C. [Unite de Catalyse et de Chimie du Solide, UMR CNRS 8181, Universite des Sciences et Technologies, 59655 Villeneuve d' Ascq (France); Rebeilleau, Michael; Dupuy, Carole; Dath, Jean Pierre [Total Petrochemicals Research, Zone industrielle CB-7181, Feluy (Belgium)

    2008-01-15

    The performance of gas oil hydrodesulfurization catalysts was successfully improved through the modification of oxidic precursors with thioglycolic acid. XPS study indicates that addition of this chelating agent affects the sulfidation of the supported metals. The higher catalytic performance was attributed to an optimization of the nature and morphology of the active phase due to the use of this chelating agent which enables a simultaneous sulfidation of both Co and Mo atoms. (author)

  10. Study of crystallization behavior of poly(phenylene sulfide)

    OpenAIRE

    Liliana B. Nohara; Evandro L. Nohara; Andreza Moura; Joseane M. R. P. Gonçalves; Michelle L. Costa; Mirabel C. Rezende

    2006-01-01

    Poly(phenylene sulfide) (PPS) is an engineering thermoplastic polymer that presents high temperature resistance (glass transition temperature around 85 ºC and melting point at 285 ºC). These properties combined with its mechanical properties and its high chemical resistance allows its use in technological applications such as molding resins and as matrix for structural thermoplastic composites. During the manufacture of thermoplastic composites, the polymer is exposed to repeated melting, que...

  11. Why does the Conductivity of a Nickel Catalyst Increase during Sulfidation? An Exemplary Study Using an In Operando Sensor Device

    Directory of Open Access Journals (Sweden)

    Peter Fremerey

    2015-10-01

    Full Text Available In order to study the sulfidation of a catalyst fixed bed, an in operando single pellet sensor was designed. A catalyst pellet from the fixed bed was electrically contacted and its electrical response was correlated with the catalyst behavior. For the sulfidation tests, a nickel catalyst was used and was sulfidized with H2S. This catalyst had a very low conductivity in the reduced state. During sulfidation, the conductivity of the catalyst increased by decades. A reaction from nickel to nickel sulfide occurred. This conductivity increase by decades during sulfidation had not been expected since both nickel and nickel sulfides behave metallic. Only by assuming a percolation phenomenon that originates from a volume increase of the nickel contacts when reacting to nickel sulfides, this effect can be explained. This assumption was supported by sulfidation tests with differently nickel loaded catalysts and it was quantitatively estimated by a general effective media theory. The single pellet sensor device for in operando investigation of sulfidation can be considered as a valuable tool to get further insights into catalysts under reaction conditions.

  12. Why does the Conductivity of a Nickel Catalyst Increase during Sulfidation? An Exemplary Study Using an In Operando Sensor Device.

    Science.gov (United States)

    Fremerey, Peter; Jess, Andreas; Moos, Ralf

    2015-01-01

    In order to study the sulfidation of a catalyst fixed bed, an in operando single pellet sensor was designed. A catalyst pellet from the fixed bed was electrically contacted and its electrical response was correlated with the catalyst behavior. For the sulfidation tests, a nickel catalyst was used and was sulfidized with H₂S. This catalyst had a very low conductivity in the reduced state. During sulfidation, the conductivity of the catalyst increased by decades. A reaction from nickel to nickel sulfide occurred. This conductivity increase by decades during sulfidation had not been expected since both nickel and nickel sulfides behave metallic. Only by assuming a percolation phenomenon that originates from a volume increase of the nickel contacts when reacting to nickel sulfides, this effect can be explained. This assumption was supported by sulfidation tests with differently nickel loaded catalysts and it was quantitatively estimated by a general effective media theory. The single pellet sensor device for in operando investigation of sulfidation can be considered as a valuable tool to get further insights into catalysts under reaction conditions. PMID:26512669

  13. Antifoaming materials studies in G.S. (Girlder sulfide) heavy water plants. Chemical and thermical stability. Pt. 3

    International Nuclear Information System (INIS)

    In Girlder sulfide (G.S.) heavy water plants hydrogen sulfide-water systems are inherentely foaming, so the adding of antifoaming materials is of great importance. These may be of high volatility, pyrolizable or chemically unstable in plant operation conditions (water and hydrogen sulfide at 2 MPa, up to 230 deg C). Five commercial surfactants were studied from the point of view of their chemical and thermical stability in order to select the most suitable. (Author)

  14. Studies on silicone based antifoaming agents to be used in G.S. (Girlder sulfide) heavy water plants

    International Nuclear Information System (INIS)

    In Girlder sulfide (G.S.) heavy water plants hydrogen sulfide-water systems are inherentely foaming, so the adding of antifoaming materials is of great importance. These may be of high volatility, pyrolizable or chemically unstable in plant operation conditions (water and hydrogen sulfide at 2MPa, up to 230 deg C). Six commercial silicone based antifoaming agents were studied from the point of view of their chemical and thermical stability in order to select the most suitable. (Author)

  15. Experimental Study of Gas Explosions in Hydrogen Sulfide-Natural Gas-Air Mixtures

    OpenAIRE

    Gaathaug, André Vagner; Bjerketvedt, Dag; Vågsæther, Knut; Nilsen, Sandra Hennie

    2014-01-01

    An experimental study of turbulent combustion of hydrogen sulfide (H2S) and natural gas was performed to provide reference data for verification of CFD codes and direct comparison. Hydrogen sulfide is present in most crude oil sources, and the explosion behaviour of pure H2S and mixtures with natural gas is important to address. The explosion behaviour was studied in a four-meter-long square pipe.The first two meters of the pipe had obstacles while the rest was smooth. Pressure transducers...

  16. Experimental Study of Gas Explosions in Hydrogen Sulfide-Natural Gas-Air Mixtures

    OpenAIRE

    André Vagner Gaathaug; Dag Bjerketvedt; Knut Vaagsaether; Sandra Hennie Nilsen

    2014-01-01

    An experimental study of turbulent combustion of hydrogen sulfide (H2S) and natural gas was performed to provide reference data for verification of CFD codes and direct comparison. Hydrogen sulfide is present in most crude oil sources, and the explosion behaviour of pure H2S and mixtures with natural gas is important to address. The explosion behaviour was studied in a four-meter-long square pipe. The first two meters of the pipe had obstacles while the rest was smooth. Pressure transducers w...

  17. Allyl-silica Hybrid Monoliths For Chromatographic Application

    Science.gov (United States)

    Guo, Wenjuan

    Column technology continues to be the most investigated topics in the separation world, since the column is the place where the chromatographic separation happens, making it the heart of the separation system. Allyl-silica hybrid monolithic material has been exploited as support material and potential stationary phases for liquid chromatography; the stationary phase anchored to the silica surface by Si-C bond, which is more pH stable than traditional stationary phase. First, nuclear magnetic resonance spectroscopy has been used to study the sol in the synthesis of allyl-silica hybrid monoliths. Allyl-trimethoxysilane (allyl-TrMOS), dimethyldimethoxysilane (DMDMOS) and tetramethoxysilane (TMOS) have been served as co-precursors in the sol-gel synthesis of organo-silica hybrid monolithic columns for liquid chromatography (LC). 29Si nuclear magnetic resonance (NMR) and 1H NMR spectroscopy were employed to monitor reaction profiles for the acid-catalyzed hydrolysis and initial condensation reactions of the individual precursor and the hybrid system. 29Si-NMR has also been used to identify different silane species formed during the reactions. The overall hydrolysis rate has been found to follow the trend DMDMOS > allyl-TrMOS > TMOS, if each precursor is reacted individually (homo-polymerization). Precursors show different hydrolysis rate when reacted together in the hybrid system than they are reacted individually. Cross-condensation products of TMOS and DMDMOS (QD) arise about 10 minutes of initiation of the reaction. The allyl-silica monolithic columns for capillary liquid chromatography can only be prepared in capillaries with 50 im internal diameter with acceptable performance. One of the most prominent problems related to the synthesis of silica monolithic structures is the volume shrinkage. The synthesis of allylfunctionalized silica hybrid monolithic structures has been studied in an attempt to reduce the volume shrinkage during aging, drying and heat treatment

  18. 烯丙基苯并恶嗪改性BT树脂的研究%Study on Bismaleimide-Triazine Resin Modiifed by Allyl Benzoxazine

    Institute of Scientific and Technical Information of China (English)

    陈虹; 寇开昌; 王益群; 张宇; 卓龙海

    2014-01-01

    采用熔融缩聚法合成了烯丙基苯并恶嗪(Boz-allyl),并利用傅立叶变换红外光谱,磁共振氢谱对其表征。用动态扫描量热与热重分析研究了其固化过程及热性能,随后用其对双马来酰亚胺-三嗪树脂(BT树脂)改性,并分析了改性树脂的力学性能。结果表明,Boz-allyl存在两种固化机理,固化物5%和10%热失重温度分别为325,385℃,在800℃时质量保持率仍可达34%,说明其具有优良的热稳定性和耐烧蚀性,用其改性后BT树脂韧性明显提高,当Boz-allyl质量分数为8%时冲击和弯曲强度达到最大值,分别为11.32 kJ/m2和127.11 MPa。%An allyl benzoxazine(Boz-allyl) was synthesized by melt polycondensation method and the structures of Boz-allyl was confirmed by Fourier transform infrared spectroscopy and nuclear magnetic resonance. Using differential scanning calorimetery and thermal gravimetric analysis,the curing behavior and thermal property of it were probed. Then the bismaleimide-triazine resin modified by Boz-allyl was prepared and its mechanical properties was investigated. The results show a dual cure pattern of Boz-allyl ,while the 5%and 10%weight loss temperatures of polybenzoxazine is 325℃and 385℃respectively,with quality retention rate up to 34%at 800℃,which reveals good heat resistance and ablation resistance. The addition of Boz-allyl into BT resin significantly improves toughness and strength,its impact strength and flexural strength is up to their maximums of 11.32 kJ/m2 and 127.11 MPa when the mass fraction of Boz-allyl is 8%.

  19. Petrographic Studies of Sulfide Assemblages in the Allende CV3 Carbonaceous Chondrite

    Science.gov (United States)

    Wetteland, Chris; Brearley, Adrian J.

    2002-01-01

    Studies of sulfides in Allende show that pyrrhotite occurs mainly within chondrules and has been partially replaced by pentlandite. Ni and Co contents of pentlandites within individual chondrules are homogeneous, but are variable between chondrules. Additional information is contained in the original extended abstract.

  20. Reflectivity and microhardness of sulfide minerals as genetic information source (case study: pyrite and arsenopyrite)

    Science.gov (United States)

    Sinkina, E. A.; Korovkin, M. V.; Savinova, O. V.; Makarova, A. A.

    2016-03-01

    Reflectivity and microhardness of pyrite and arsenopyrite of black shale gold-ore deposits in Chertovo Koryto (Patom upland) were studied. It was found that sulfides of different generations are characterized by different values of above-mentioned parameters which is associated mechanical and isomorphic impurities.

  1. A computational study of adhesion between rubber and metal sulfides at rubber–brass interface

    International Nuclear Information System (INIS)

    Highlights: • An atomic level model for brass–rubber interactions has been presented. • The main adhesion force has been tracked to the rubber sulfur–brass zinc or brass copper interaction. • The model gives new understanding of the adhesion and can be used for further developments of the system. - Abstract: Computational study at level of density functional theory has been carried out in order to investigate the adhesion between rubber and brass plated steel cord, which has high importance in tire manufacturing. Adsorption of natural rubber based adsorbate models has been studied on zinc sulfide, ZnS(1 1 0), and copper sulfide, Cu2S(1 1 1) and CuS(0 0 1), surfaces as the corresponding phases are formed in adhesive interlayer during rubber vulcanization. Saturated hydrocarbons exhibited weak interactions, whereas unsaturated hydrocarbons and sulfur-containing adsorbates interacted with the metal atoms of sulfide surfaces more strongly. Sulfur-containing adsorbates interacted with ZnS(1 1 0) surface stronger than unsaturated hydrocarbons, whereras both Cu2S(1 1 1) and CuS(0 0 1) surfaces showed opposite adsorption preference as unsaturated hydrocarbons adsorbed stronger than sulfur-containing adsorbates. The different interaction strength order can play role in rubber–brass adhesion with different relative sulfide concentrations. Moreover, Cu2S(1 1 1) surface exhibits higher adsorption energies than CuS(0 0 1) surface, possibly indicating dominant role of Cu2S in the adhesion between rubber and brass

  2. Optical, XPS and XRD Studies of Semiconducting Copper Sulfide Layers on a Polyamide Film

    International Nuclear Information System (INIS)

    Copper sulfide layers were formed on polyamide PA 6 surface using the sorption-diffusion method. Polymer samples were immersed for 4 and 5 h in 0.15 mol dm-3 K2S5O6 solutions and acidified with HCl (0.1 mol dm-3) at 20 degree C. After washing and drying, the samples were treated with Cu(I) salt solution. The samples were studied by UV/VIS, X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) methods. All methods confirmed that on the surface of the polyamide film a layer of copper sulfide was formed. The copper sulfide layers are indirect band-gap semiconductors. The values of Ebg are 1.25 and 1.3 eV for 4 h and 5 h sulfured PA 6 respectively. Copper XPS spectra analyses showed Cu(I) bonds only in deeper layers of the formed film, while in sulfur XPS S 2p spectra dominating sulfide bonds were found after cleaning the surface with Ar+ ions. It has been established by the XRD method that, beside Cu2S, the layer contains Cu 1.9375 S as well. For PA 6 initially sulfured 4 h, grain size for chalcocite, Cu2S, was 35.60 nm and for djurleite, Cu 1.9375 S, it was 54.17 nm. The sheet resistance of the obtained layer varies from 6300 to 102 O/cm2.

  3. Regioselective hydroformylation of allylic alcohols.

    Science.gov (United States)

    Lightburn, Thomas E; De Paolis, Omar A; Cheng, Ka H; Tan, Kian L

    2011-05-20

    A highly regioselective hydroformylation of allylic alcohols is reported toward the synthesis of β-hydroxy-acid and aldehyde products. The selectivity is achieved through the use of a ligand that reversibly binds to alcohols in situ, allowing for a directed hydroformylation to occur. The application to trisubstituted olefins was also demonstrated, which yields a single diastereomer product consistent with a stereospecific addition of CO and hydrogen. PMID:21504208

  4. Regioselective Hydroformylation of Allylic Alcohols

    Science.gov (United States)

    Lightburn, Thomas E.; De Paolis, Omar A.; Cheng, Ka H.; Tan, Kian L.

    2011-01-01

    A highly regioselective hydroformylation of allylic alcohols is reported towards the synthesis of β-hydroxy-acid and aldehyde products. The selectivity is achieved through the use of a ligand that reversibly binds to alcohols in situ, allowing for a directed hydroformylation to occur. The application to trisubstituted olefins was also demonstrated, which yields a single diastereomer product consistent with a stereospecific addition of CO and hydrogen. PMID:21504208

  5. Studies on ternary silver sulfides; Fukugo gin ryukabutsu ni kansuru kenkyu

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-10-31

    Some sulfides containing silver show high ion mobility based on movability of silver, whose application is expected. Studies have been carried out centrally on synthesis of new compounds of ternary silver sulfides by elucidating the relationship among their compositions, structures and properties by means of crystal chemical studies mainly on their phase relationship. A few new compounds have been synthesized, such as the ones having the argyrodite family compound structure including transition metals. The synthesizing process takes a kind of turbulent liquid state structure at elevated temperatures because of movability of silver, but silver is fixed at low temperatures in different sites between skeleton structures made by other atoms. These studies on phase transfer, structures, and silver movability have been based on X-ray diffraction, infrared and Raman spectroscopic measurements, NMR, measurements of electric and thermal characteristics. For the studies related to compositions and structures of ternary metal sulfides which take compound crystalline structure, a structure analyzing method based on multi-dimensional hyperspatial groups was used. This paper reports the summary of the studies in seven chapters, and dwells on the remaining problems and future prospects. 158 refs., 114 figs., 65 tabs.

  6. Preparation and study of thickness dependent electrical characteristics of zinc sulfide thin films

    Indian Academy of Sciences (India)

    A U Ubale; D K Kulkarni

    2005-02-01

    Zinc sulfide thin films have been deposited onto glass substrates by chemical bath deposition. The various deposition parameters such as volume of sulfide ion source, pH of bath, deposition time, temperature etc are optimized. Thin films of ZnS with different thicknesses of 76–332 nm were prepared by changing the deposition time from 6–20 h at 30°C temperature. The effect of film thickness on structural and electrical properties was studied. The electrical resistivity was decreased from 1.83 × 105 -cm to 0.363 × 105 -cm as film thickness decreased from 332 nm to 76 nm. The structural and activation energy studies support this decrease in the resistivity due to improvement in crystallinity of the films which would increase the charge carrier mobility and decrease in defect levels with increase in the thickness.

  7. Optical, XPS and XRD Studies of Semiconducting Copper Sulfide Layers on a Polyamide Film

    Directory of Open Access Journals (Sweden)

    Mindaugas Andrulevičius

    2009-01-01

    Full Text Available Copper sulfide layers were formed on polyamide PA 6 surface using the sorption-diffusion method. Polymer samples were immersed for 4 and 5 h in 0.15 mol⋅dm−3 K2S5O6 solutions and acidified with HCl (0.1 mol⋅dm−3 at 20∘C. After washing and drying, the samples were treated with Cu(I salt solution. The samples were studied by UV/VIS, X-ray diffraction (XRD and X-ray photoelectron spectroscopy (XPS methods. All methods confirmed that on the surface of the polyamide film a layer of copper sulfide was formed. The copper sulfide layers are indirect band-gap semiconductors. The values of Ebg are 1.25 and 1.3 eV for 4 h and 5 h sulfured PA 6 respectively. Copper XPS spectra analyses showed Cu(I bonds only in deeper layers of the formed film, while in sulfur XPS S 2p spectra dominating sulfide bonds were found after cleaning the surface with Ar+ ions. It has been established by the XRD method that, beside Cu2S, the layer contains Cu1.9375S as well. For PA 6 initially sulfured 4 h, grain size for chalcocite, Cu2S, was ∼35.60 nm and for djurleite, Cu1.9375S, it was 54.17 nm. The sheet resistance of the obtained layer varies from 6300 to 102 Ω/cm2.

  8. Cluster model studies on catalytic sulfidation of MoO3

    International Nuclear Information System (INIS)

    MoS2-based catalysts, initially prepared from MoO3, are known to yield high activity and selectivity for the production of mixed alcohols. This makes research on the sulfidation of MoO3 quite important. Here we apply density-functional theory (DFT) together with large surface clusters (cluster code StoBe) to study the sulfidation of the MoO3(010) surface as well as hydrogen adsorption at an atomic level. Surface oxygen is always found to bind more strongly with its substrate than its sulfur substitute with binding distances that are shorter for oxygen than for sulfur. Sulfur-oxygen exchange reactions are energetically preferred over sulfur adsorption at MoO3(010). Further, sulfur binding is found to be facilitated by the existence of surface oxygen vacancies where sulfur substitution takes place preferentially at the singly coordinated O(1) site. Hydrogen adsorption at the perfect and sulfidic surface leads to stable OH, H2O and SH, H2S groups which are quite weakly bound and may easily adsorb. Thus, the presence of pre-adsorbed hydrogen facilitates oxygen and sulfur removal from the MoO3(010) surface which is in qualitative agreement with earlier findings.

  9. Catalytic deallylation of allyl- and diallylmalonates.

    Science.gov (United States)

    Necas, David; Turský, Matyás; Kotora, Martin

    2004-08-25

    Substituted allylmalonates undergo the selective C-C bond cleavage in the presence of triethylaluminum and a catalytic amount of nickel and ruthenium phosphine complexes, resulting in the loss of the allyl moiety and formation of monosubstituted malonates. Comparison of reactivity of the nickel and ruthenium complexes showed that the use of the former is general with respect to the structure of the substituted allylmalonates, and the activity of the latter depended on the substitution pattern of the double bond of the allylic moiety. The smooth deallylation may encourage the use of the allyl group as a protective group for the acidic hydrogen in malonates. PMID:15315416

  10. Highly enantio- and diastereoselective allylic alkylation of Morita-Baylis-Hillman carbonates with allyl ketones

    KAUST Repository

    Tong, Guanghu

    2013-05-17

    The asymmetric allylic alkylation of Morita-Baylis-Hillman (MBH) carbonates with allyl ketones has been developed. The α-regioselective alkylation adducts, containing a hexa-1,5-diene framework with important synthetic value, were achieved in up to 83% yield, >99% ee, and 50:1 dr by using a commercially available Cinchona alkaloid as the catalyst. From the allylic alkylation adduct, a cyclohexene bearing two adjacent chiral centers was readily prepared. © 2013 American Chemical Society.

  11. Bradykinetic alcohol dehydrogenases make yeast fitter for growth in the presence of allyl alcohol

    OpenAIRE

    Plapp, Bryce V.; Lee, Ann Ting-I.; Khanna, Aditi; Pryor, John M.

    2012-01-01

    Previous studies showed that fitter yeast (Saccharomyces cerevisiae) that can grow by fermenting glucose in the presence of allyl alcohol, which is oxidized by alcohol dehydrogenase I (ADH1) to toxic acrolein, had mutations in the ADH1 gene that led to decreased ADH activity. These yeast may grow more slowly due to slower reduction of acetaldehyde and a higher NADH/NAD+ ratio, which should decrease the oxidation of allyl alcohol. We determined steady-state kinetic constants for three yeast AD...

  12. Experimental Study of Gas Explosions in Hydrogen Sulfide-Natural Gas-Air Mixtures

    Directory of Open Access Journals (Sweden)

    André Vagner Gaathaug

    2014-01-01

    Full Text Available An experimental study of turbulent combustion of hydrogen sulfide (H2S and natural gas was performed to provide reference data for verification of CFD codes and direct comparison. Hydrogen sulfide is present in most crude oil sources, and the explosion behaviour of pure H2S and mixtures with natural gas is important to address. The explosion behaviour was studied in a four-meter-long square pipe. The first two meters of the pipe had obstacles while the rest was smooth. Pressure transducers were used to measure the combustion in the pipe. The pure H2S gave slightly lower explosion pressure than pure natural gas for lean-to-stoichiometric mixtures. The rich H2S gave higher pressure than natural gas. Mixtures of H2S and natural gas were also studied and pressure spikes were observed when 5% and 10% H2S were added to natural gas and also when 5% and 10% natural gas were added to H2S. The addition of 5% H2S to natural gas resulted in higher pressure than pure H2S and pure natural gas. The 5% mixture gave much faster combustion than pure natural gas under fuel rich conditions.

  13. Cationic ruthenium-cyclopentadienyl-diphosphine complexes as catalysts for the allylation of phenols with allyl alcohol: relation between structure and catalytic performance in O- vs. C-allylation

    NARCIS (Netherlands)

    van Rijn, J.A.; Lutz, M.; von Chrzanowski, L.S.; Spek, A.L.; Bouwman, E.; Drent, E.

    2009-01-01

    A new catalytic method has been investigated to obtain either O- or C-allylated phenolic products using allyl alcohol or diallyl ether as the allyl donor. With the use of new cationic ruthenium(II) complexes as catalyst, both reactions can be performed with good selectivity. Active cationic Ru(II) c

  14. N-Allylation of amines with allyl acetates using chitosan-immobilized palladium

    Science.gov (United States)

    A simple procedure for N-Allylation of allyl Acetates has been developed using a biodegradable and easily recyclable heterogeneous chitosan-supported palladium catalyst. The general methodology, applicable to wide range of substrates, has sustainable features that include a ligan...

  15. Compound list: allyl alcohol [Open TG-GATEs

    Lifescience Database Archive (English)

    Full Text Available allyl alcohol AA 00010 ftp://ftp.biosciencedbc.jp/archive/open-tggates/LATEST/Human/in_vitro/allyl_alcohol....Human.in_vitro.Liver.zip ftp://ftp.biosciencedbc.jp/archive/open-tggates/LATEST/Rat/in_vitro/allyl_alcohol...dbc.jp/archive/open-tggates/LATEST/Rat/in_vivo/Liver/Repeat/allyl_alcohol.Rat.in_vivo.Liver.Repeat.zip ftp:/.../ftp.biosciencedbc.jp/archive/open-tggates/LATEST/Rat/in_vivo/Kidney/Single/allyl_alcohol.Rat.in_vivo.Kidney....Single.zip ftp://ftp.biosciencedbc.jp/archive/open-tggates/LATEST/Rat/in_vivo/Kidney/Repeat/allyl_alcohol.Rat.in_vivo.Kidney.Repeat.zip ...

  16. Rotational Spectroscopy of Isocyanic Molecules: Allyl Isocyanide and Diisocyanomethane

    Science.gov (United States)

    Motiyenko, R. A.; Margules, L.; Haykal, I.; Huet, T. R.; Cocinero, E. J.; Ecija, P.; Fernandez, J. A.; Castano, F.; Lesarri, A.; Guillemin, J.-C.

    2012-06-01

    Isocyanides are less stable isomers of nitriles and some of them have already been observed in the interstellar medium (HNC, CH_3NC, HCCNC). But still there exists a lack of experimental spectroscopic data on simple isocyanic molecules that can represent potential astrophysical interest. In this view we have performed high resolution studies of rotational spectra of allyl isocyanide (CH_2=CH--CH_2--NC) and diisocyanomethane (CN--CH_2--NC). The rotational spectra of allyl isocyanide have been measured in the frequency range 6 -- 18 GHz by means of FTMW spectrometer in Bilbao and in the frequency range 150 -- 945 GHz by means of classic absorption spectroscopy in Lille. Two stable confomers of allyl isocyanide have been observed in both series of measurements. In addition, all 13C-monosubstituted isotopologues and 15N isotopologues were detected in natural abundance. Due to much lower kinetic stability the rotational spectrum of diisocyanomethane has been measured only in absorption using the Lille spectrometer. The spectral assignments have been supported by high-level quantum chemical calculations. For both molecules accurate sets of rotational and centrifugal distortion constants (up to the octics) have been produced. As a result, reliable predictions of transitions frequencies suitable for astrophysical detection have been obtained for both molecules. Finally, the effective and substitution structures were determined for the two conformers of allyl isocyanide, comparing the result with ab initio data. This work is supported by Centre Nationale d'Etudes Spatiales (CNES), Action sur Projet Physico-Chimie du Milieu Interstellaire (PCMI-CNRS) and by the contract ANR-08-BLAN-0054. Spanish part acknowledges funding from the MICINN and the MINECO.

  17. A novel method for improving cerussite sulfidization

    Science.gov (United States)

    Feng, Qi-cheng; Wen, Shu-ming; Zhao, Wen-juan; Cao, Qin-bo; Lü, Chao

    2016-06-01

    Evaluation of flotation behavior, solution measurements, and surface analyses were performed to investigate the effects of chloride ion addition on the sulfidization of cerussite in this study. Micro-flotation tests indicate that the addition of chloride ions prior to sulfidization can significantly increase the flotation recovery of cerussite, which is attributed to the formation of more lead sulfide species on the mineral surface. Solution measurement results suggest that the addition of chloride ions prior to sulfidization induces the transformation of more sulfide ions from pulp solution onto the mineral surface by the formation of more lead sulfide species. X-ray diffraction and energy-dispersive spectroscopy indicate that more lead sulfide species form on the mineral surface when chloride ions are added prior to sulfidization. These results demonstrate that the addition of chloride ions prior to sulfidization can significantly improve the sulfidization of cerussite, thereby enhancing the flotation performance.

  18. A STUDY TO EVALUATE CARBON MONOXIDE AND HYDROGEN SULFIDE CONTINUOUS EMISSION MONITORS AT AN OIL REFINERY

    Science.gov (United States)

    An eleven month field evaluation was done on five hydrogen sulfide and four carbon monoxide monitors located at an oil refinery. The hydrogen sulfide monitors sampled a fuel gas feed line and the carbon monoxide monitors sampled the emissions from a fluid cat cracker (FCC). Two o...

  19. Transition‐Metal‐Free Borylation of Allylic and Propargylic Alcohols

    Science.gov (United States)

    Miralles, Núria; Alam, Rauful

    2016-01-01

    Abstract The base‐catalyzed allylic borylation of tertiary allylic alcohols allows the synthesis of 1,1‐disubstituted allyl boronates, in moderate to high yield. The unexpected tandem performance of the Lewis acid–base adduct, [Hbase]+[MeO‐B2pin2]− favored the formation of 1,2,3‐triborylated species from the tertiary allylic alcohols and 1‐propargylic cyclohexanol at 90 °C. PMID:26934578

  20. Transition-Metal-Free Borylation of Allylic and Propargylic Alcohols.

    Science.gov (United States)

    Miralles, Núria; Alam, Rauful; Szabó, Kálmán J; Fernández, Elena

    2016-03-18

    The base-catalyzed allylic borylation of tertiary allylic alcohols allows the synthesis of 1,1-disubstituted allyl boronates, in moderate to high yield. The unexpected tandem performance of the Lewis acid-base adduct, [Hbase](+) [MeO-B2 pin2 ](-) favored the formation of 1,2,3-triborylated species from the tertiary allylic alcohols and 1-propargylic cyclohexanol at 90 °C. PMID:26934578

  1. Study on the occurrence of platinum in Xinjie Cu-Ni sulfide deposits by a combination of SPM and NAA

    International Nuclear Information System (INIS)

    A combination of neutron-activation analysis (NAA) and scanning proton microprobe (SPM) was used to study the distribution of platinum-group elements (PGEs) in rocks and ores from Xinjie Cu-Ni deposit. The minimum detection limits of PGEs by NAA had been much improved by means of a nickel-sulfide fire-assay technique for pre-concentration of PGEs in the ore samples. A simple and effective method was developed for true element mapping in SPM experiments. A pair of moveable absorption filters was set up in the target chamber for high sensitivities of both major and trace elements. The bulk analysis results by NNA indicated that the PGE mineralization occurred at the base of Xinjie layered intrusion in clino-pyroxenite rocks and the Cu-Ni sulfide minerals disseminated within the rocks had high abundance level of PGEs. However, the micro-PIXE analysis of the Cu-Ni sulfide mineral grains did not find PGEs above the MDL of (6-9) x 10-6 for Rh, Ru and Pd, and 6- x 10-6 for Pt. The search for platinum occurrence in sulfide minerals was followed by scanning analysis of SPM when some smaller platinum enriched grains were found in the sulfide minerals. The microscopic analysis results suggested that platinum occurred in the Cu-Ni sulfide matrix as independent arsenide mineral grains. The chemical formula of the arsenide sperrylite was PtAs2. The information of the platinum occurrence was helpful to future mineralogical research and mineral processing and beneficiation of the Cu-Ni deposit

  2. In situ solvothermal growth of metal-organic framework-5 supported on porous copper foam for noninvasive sampling of plant volatile sulfides.

    Science.gov (United States)

    Hu, Yuling; Lian, Haixian; Zhou, Langjun; Li, Gongke

    2015-01-01

    The present study reported on an in situ solvothermal growth method for immobilization of metal-organic framework MOF-5 on porous copper foam support for enrichment of plant volatile sulfides. The porous copper support impregnated with mother liquor of MOF-5 anchors the nucleation and growth of MOF crystallites at its surface, and its architecture of the three-dimensional channel enables accommodation of the MOF-5 crystallite seed. A continuous and well-intergrown MOF-5 layer, evidenced from scanning electron microscope imaging and X-ray diffraction, was successfully immobilized on the porous metal bar with good adhesion and high stability. Results show that the resultant MOF-5 coating was thermally stable up to 420 °C and robust enough for replicate extraction for at least 200 times. The MOF-5 bar was then applied to the headspace sorptive extraction of the volatile organic sulfur compounds in Chinese chive and garlic sprout in combination with thermal desorption-gas chromatography/mass spectrometry. It showed high extraction sensitivity and good selectivity to these plant volatile sulfides owing to the extraordinary porosity of the metal-organic framework as well as the interaction between the S-donor sites and the surface cations at the crystal edges. Several primary sulfur volatiles containing allyl methyl sulfide, dimethyl disulfide, diallyl sulfide, methyl allyl disulfide, and diallyl disulfide were quantified. Their limits of detection were found to be in the range of 0.2-1.7 μg/L. The organic sulfides were detected in the range of 6.0-23.8 μg/g with recoveries of 76.6-100.2% in Chinese chive and 11.4-54.6 μg/g with recoveries of 77.1-99.8% in garlic sprout. The results indicate the immobilization of MOF-5 on copper foam provides an efficient enrichment formats for noninvasive sampling of plant volatiles. PMID:25435245

  3. Enantioselective synthesis of fluorinated branched allylic compounds via Ir-catalyzed allylations of functionalized fluorinated methylene derivatives.

    Science.gov (United States)

    Zhang, Hongbo; Chen, Jiteng; Zhao, Xiao-Ming

    2016-08-14

    Enantioselective introduction of the functionalized monofluorinated methylenes into the allylic fragment under Ir catalysis has been realized, which gave the fluorinated branched allyl products in good to high yields with excellent regio- and enantioselectivities. PMID:27383920

  4. Kinetic Resolution of Racemic and Branched Monosubstituted Allylic Acetates by a Ruthenium-Catalyzed Regioselective Allylic Etherification.

    Science.gov (United States)

    Shinozawa, Toru; Terasaki, Shou; Mizuno, Shota; Kawatsura, Motoi

    2016-07-01

    We demonstrated the kinetic resolution of racemic and branched monosubstituted allylic acetates by a ruthenium-catalyzed regioselective allylic etherification. The reaction was effectively catalyzed by the chiral ruthenium catalyst, which was generated by [RuCl2(p-cymene)]2 and (S,S)-iPr-pybox and a catalytic amount of TFA, and both the allylic etherification product and recovered allylic acetate were obtained as an enantiomerically enriched form with up to a 103 s value. PMID:27276556

  5. Allylic Nitro Compounds as Nitrite Donors

    OpenAIRE

    Chakrapani, Harinath; Gorczynski, Michael J.; King, S Bruce

    2006-01-01

    Allylic nitro compounds were synthesized and evaluated as organic sources of nitrite and nitric oxide. Unactivated allylic nitro compounds do not spontaneously release nitrite and nucleophile promoted nitrite release is slow. However, 2-(nitromethyl)-cyclohex-1-ene-3-one spontaneously dissociates in buffer (pH = 7.4) to release nitrite with a kobs = 1.6 × 10−5 s−1. In the presence of L-cysteine, this compound rapidly yields nitrite and reacts with hemoglobin similarly to sodium nitrite. Struc...

  6. A study on the mechanism of stress corrosion cracking of duplex stainless steels in hot alkaline-sulfide solution

    Science.gov (United States)

    Chasse, Kevin Robert

    Duplex stainless steels (DSS) generally have superior strength and corrosion resistance as compared to most standard austenitic and ferritic stainless grades owing to a balanced microstructure of austenite and ferrite. As a result of having favorable properties, DSS have been selected for the construction of equipment in pulp and paper, chemical processing, nuclear, oil and gas as well as other industries. The use of DSS has been restricted in some cases because of stress corrosion cracking (SCC), which can initiate and grow in either the ferrite or austenite phase depending on the environment. Thorough understanding of SCC mechanisms of DSS in chloride- and hydrogen sulfide-containing solutions has been useful for material selection in many environments. However, understanding of SCC mechanisms of DSS in sulfide-containing caustic solutions is limited, which has restricted the capacity to optimize process and equipment design in pulp and paper environments. Process environments may contain different concentrations of hydroxide, sulfide, and chloride, altering corrosion and SCC susceptibility of each phase. Crack initiation and growth behavior will also change depending on the relative phase distribution and properties of austenite and ferrite. The role of microstructure and environment on the SCC of standard grade UNS S32205 and lean grade UNS S32101 in hot alkaline-sulfide solution were evaluated in this work using electrochemical, film characterization, mechanical testing, X-ray diffraction, and microscopy techniques. Microstructural aspects, which included residual stress state, phase distribution, phase ratio, and microhardness, were related to the propensity for SCC crack initiation in different simulated alkaline pulping liquors at 170 °C. Other grades of DSS and reference austenitic and superferritic grades of stainless steel were studied using exposure coupons for comparison to understand compositional effects and individual phase susceptibility

  7. Interfacial tension studies between Fe-Cu-Ni sulfide and halo-norilsk basalt slag system

    Institute of Scientific and Technical Information of China (English)

    SU; Shangguo

    2005-01-01

    The interfacial tension of the matte/halo-Norilsk basalt slag systems of FeS-Cu2S-Ni3S2 and FeO-FeS were investigated using the sessile drop technique. The results indicate that interfacial tension decreases with increasing copper and nickel contents in the matte of FeS-Cu2S-Ni3S2 system while it increases with increasing oxygen content in the matte of FeO-FeS system. It is inferred from these results that two conditions are critical for the formation of giant Cu-Ni sulfide deposits. One is that mafic-ultramafic parent magma of sulfide deposits should be rich in copper and nickel where due to the low interfacial tension, it is difficult to form sulfide droplet in the early stage of magma evolution. In other words, sulfide liquid conglomeration occurs more difficultly. The other condition is that the magma emplacement should be shallow; and a lot of faults occur in the magma emplacement field. Since oxygen content is high in the environment, interfacial tension is high, which helps sulfide liquid conglomeration and consequently Cu-Ni sulfide deposits form.

  8. Palladium Catalyzed Allylic C-H Alkylation

    DEFF Research Database (Denmark)

    Engelin, Casper Junker; Fristrup, Peter

    2011-01-01

    The atom-efficiency of one of the most widely used catalytic reactions for forging C-C bonds, the Tsuji-Trost reaction, is limited by the need of preoxidized reagents. This limitation can be overcome by utilization of the recently discovered palladium-catalyzed C-H activation, the allylic C...

  9. Stereochemistry of ring-opening/cross metathesis reactions of exo- and endo-7-oxabicyclo[2.2.1]hept-5-ene-2-carbonitriles with allyl alcohol and allyl acetate

    Directory of Open Access Journals (Sweden)

    Piotr Wałejko

    2015-10-01

    Full Text Available The ROCM reactions of exo- and endo-2-cyano-7-oxanorbornenes with allyl alcohol or allyl acetate promoted by different ruthenium alkylidene catalysts were studied. The stereochemical outcome of the reactions was established. The issues concerning chemo- (ROCM vs ROMP, regio- (1-2- vs 1-3-product formation, and stereo- (E/Z isomerism selectivity of reactions under various conditions are discussed. Surprisingly good yields of the ROCM products were obtained under neat conditions.

  10. Anti-Markovnikov Hydroalkylation of Allylic Amine Derivatives via a Palladium–Catalyzed Reductive Cross-Coupling Reaction

    OpenAIRE

    DeLuca, Ryan J.; Sigman, Matthew S.

    2011-01-01

    A palladium-catalyzed hydroalkylation reaction of allylic amine derivatives by alkylzinc reagents is reported. This reductive cross-coupling yields anti-Markovnikov products using a variety of allylic amine protecting groups. Preliminary mechanistic studies suggest that a reversible β-hydride elimination/hydride insertion process furnishes the primary Pd-alkyl intermediate, which then undergoes transmetallation followed by reductive elimination to form a new sp3-sp3 carbon-carbon bond.

  11. Electrochemical Studies of Microwave Synthesised Bimetallic Sulfides Nanostructures As Faradaic Electrodes

    International Nuclear Information System (INIS)

    Highlights: • Use of microwave technology for production of nanostructured materials. • Hydrothermal microwave irradiation of NixCoyS4 with different stoichiometry. • Materials produced exhibited good Faradaic behaviour. - Abstract: A microwave irradiation method has been used to prepare mixed nickel cobalt sulfide (NixCoyS4) nanosheets with different stoichiometric composition as electrodes for electrochemical capacitors. This study has been undertaken to determine the effect of synthesis time and concentration of nickel on the morphology and pseudocapacitance behavior of the NixCoyS4. It was observed that the time had an effect on the morphology of NixCoyS4, producing sheet-like (leaf-like) morphology which curls in flower-like shapes with increase in growth (synthesis) time. The effect of morphology on the electrochemical behavior was studied by cyclic voltammetry (CV), chronopotentiometry (CP) and electrochemical impedance spectroscopy (EIS) techniques in aqueous solutions. The sample with a concentration ratio of 2:1 of nickel and cobalt (NixCoyS4-3) shows higher faradaic performance when compared to other samples grown under similar conditions but with different ratios. The maximum specific capacitance values obtained for was 1110 F g−1 at a scan rate of 5 mV s−1 for this sample. The Coulombic efficiency of the sample was ∼80% after 2000 galvanostatic charge-discharge cycles at a current density of 5 A g−1

  12. Sulfur isotope values in the sulfidic Frasassi cave system, central Italy: A case study of a chemolithotrophic S-based ecosystem

    Science.gov (United States)

    Zerkle, Aubrey L.; Jones, Daniel S.; Farquhar, James; Macalady, Jennifer L.

    2016-01-01

    Sulfide oxidation forms a critical step in the global sulfur cycle, although this process is notoriously difficult to constrain due to the multiple pathways and highly reactive intermediates involved. Multiple sulfur isotopes (δ34S and Δ33S) can provide a powerful tool for unravelling sulfur cycling processes in modern (and ancient) environments, although they have had limited application to systems with well-resolved oxidative S cycling. In this study, we report the major (δ34S) and minor (Δ33S) isotope values of sulfur compounds in streams and sediments from the sulfidic Frasassi cave system, Marche Region, Italy. These microaerophilic cave streams host prominent white biofilms dominated by chemolithotrophic organisms that oxidize sulfide to S0, allowing us to estimate S isotope fractionations associated with in situ sulfide oxidation and to evaluate any resulting isotope biosignatures. Our results demonstrate that chemolithotrophic sulfide oxidation produces 34S enrichments in the S0 products that are larger than those previously measured in laboratory experiments, with 34εS0-H2S of up to 8‰ calculated. These small reverse isotope effects are similar to those produced during phototrophic sulfide oxidation (⩽7‰), but distinct from the small normal isotope effects previously calculated for abiotic oxidation of sulfide with O2 (∼-5‰). An inverse correlation between the magnitude of 34εS0-H2S effects and sulfide availability, along with substantial differences in Δ33S, both support complex sulfide oxidation pathways and intracellular recycling of S intermediates by organisms inhabiting the biofilms. At the ecosystem level, we calculate fractionations of less than 40‰ between sulfide and sulfate in the water column and in the sediments. These fractionations are smaller than those typically calculated for systems dominated by sulfate reduction (>50‰), and contrast with the commonly held assumption that oxidative recycling of sulfide generally

  13. Synthesis of (-)-Piperitylmagnolol Featuring ortho-Selective Deiodination and Pd-Catalyzed Allylation.

    Science.gov (United States)

    Ikoma, Atsushi; Ogawa, Narihito; Kondo, Daiki; Kawada, Hiroki; Kobayashi, Yuichi

    2016-05-01

    A 1,4-addition strategy using an enone and a copper reagent was studied for the synthesis of (-)-piperitylmagnolol. A MOM-protected biphenol copper reagent was added to BF3·OEt2-activated 4-isopropylcyclohexenone, whereas 1,4-addition of protected monophenol reagents possessing an allyl group was found to be unsuccessful. The allyl group was later attached to the p-,p'-diiodo-biphenol ring by Pd-catalyzed coupling with allylborate. The aforementioned iodide was synthesized using a new method for ortho-selective deiodination of o-,p-diiodophenols. PMID:27109890

  14. Pressure Dependent Product Formation in the Photochemically Initiated Allyl + Allyl Reaction

    Directory of Open Access Journals (Sweden)

    Thomas Zeuch

    2013-11-01

    Full Text Available Photochemically driven reactions involving unsaturated radicals produce a thick global layer of organic haze on Titan, Saturn’s largest moon. The allyl radical self-reaction is an example for this type of chemistry and was examined at room temperature from an experimental and kinetic modelling perspective. The experiments were performed in a static reactor with a volume of 5 L under wall free conditions. The allyl radicals were produced from laser flash photolysis of three different precursors allyl bromide (C3H5Br, allyl chloride (C3H5Cl, and 1,5-hexadiene (CH2CH(CH22CHCH2 at 193 nm. Stable products were identified by their characteristic vibrational modes and quantified using FTIR spectroscopy. In addition to the (re- combination pathway C3H5+C3H5 → C6H10 we found at low pressures around 1 mbar the highest final product yields for allene and propene for the precursor C3H5Br. A kinetic analysis indicates that the end product formation is influenced by specific reaction kinetics of photochemically activated allyl radicals. Above 10 mbar the (re- combination pathway becomes dominant. These findings exemplify the specificities of reaction kinetics involving chemically activated species, which for certain conditions cannot be simply deduced from combustion kinetics or atmospheric chemistry on Earth.

  15. SYNTHESIS OF ALLYL PHENYL ETHER AND CLAISEN REARRANGEMENT

    Directory of Open Access Journals (Sweden)

    Gagik Torosyan

    2011-12-01

    Full Text Available It has been established the possibility for phenol allylation on natural zeolites and them analogs. Here is demonstrated the synthesis of allyl phenol, which has wide industrial applications. The offered method in comparison with the traditional methods has more advantages – higher selectivity, smaller material and power resources consumption. It has been obtained the mixture of allylating phenols (30% in general with allyl phenyl ether (1 with 80% yields. At 600 K is obtained allylphenyl ether, at 700 K beginning the formation of allyl phenols, which is the result of direct C-allylation of the aromatic ring. It has been investigated the possibility of Claisen rearrangement in the same conditions. All of that are established by gas-liquid chromatography and liquid chromatography data.

  16. Transient overexpression of adh8a increases allyl alcohol toxicity in zebrafish embryos.

    Science.gov (United States)

    Klüver, Nils; Ortmann, Julia; Paschke, Heidrun; Renner, Patrick; Ritter, Axel P; Scholz, Stefan

    2014-01-01

    Fish embryos are widely used as an alternative model to study toxicity in vertebrates. Due to their complexity, embryos are believed to more resemble an adult organism than in vitro cellular models. However, concerns have been raised with respect to the embryo's metabolic capacity. We recently identified allyl alcohol, an industrial chemical, to be several orders of magnitude less toxic to zebrafish embryo than to adult zebrafish (embryo LC50 = 478 mg/L vs. fish LC50 = 0.28 mg/L). Reports on mammals have indicated that allyl alcohol requires activation by alcohol dehydrogenases (Adh) to form the highly reactive and toxic metabolite acrolein, which shows similar toxicity in zebrafish embryos and adults. To identify if a limited metabolic capacity of embryos indeed can explain the low allyl alcohol sensitivity of zebrafish embryos, we compared the mRNA expression levels of Adh isoenzymes (adh5, adh8a, adh8b and adhfe1) during embryo development to that in adult fish. The greatest difference between embryo and adult fish was found for adh8a and adh8b expression. Therefore, we hypothesized that these genes might be required for allyl alcohol activation. Microinjection of adh8a, but not adh8b mRNA led to a significant increase of allyl alcohol toxicity in embryos similar to levels reported for adults (LC50 = 0.42 mg/L in adh8a mRNA-injected embryos). Furthermore, GC/MS analysis of adh8a-injected embryos indicated a significant decline of internal allyl alcohol concentrations from 0.23-58 ng/embryo to levels below the limit of detection (< 4.6 µg/L). Injection of neither adh8b nor gfp mRNA had an impact on internal allyl alcohol levels supporting that the increased allyl alcohol toxicity was mediated by an increase in its metabolization. These results underline the necessity to critically consider metabolic activation in the zebrafish embryo. As demonstrated here, mRNA injection is one useful approach to study the role of candidate enzymes involved in

  17. Studying inhibition of calcium oxalate stone formation: an in vitro approach for screening hydrogen sulfide and its metabolites

    Directory of Open Access Journals (Sweden)

    S. Vaitheeswari

    2015-06-01

    Full Text Available ABSTRACTPurpose:Calcium oxalate urolithiasis is one of the most common urinary tract diseases and is of high prevalence. The present study proposes to evaluate the antilithiatic property of hydrogen sulfide and its metabolites like thiosulfate & sulfate in an in vitro model.Materials and Methods:The antilithiatic activity of sodium hydrogen sulfide (NaSH, sodium thiosulfate (Na2S2O3 and sodium sulfate (Na2SO4 on the kinetics of calcium oxalate crystal formation was investigated both in physiological buffer and in urine from normal and recurrent stone forming volunteers. The stones were characterized by optical and spectroscopic techniques.Results:The stones were characterized to be monoclinic, prismatic and bipyramidal habit which is of calcium monohydrate and dihydrate nature. The FTIR displayed fingerprint corresponding to calcium oxalate in the control while in NaSH treated, S=O vibrations were visible in the spectrum. The order of percentage inhibition was NaSH>Na2S2O3>Na2SO4.Conclusion:Our study indicates that sodium hydrogen sulfide and its metabolite thiosulfate are inhibitors of calcium oxalate stone agglomeration which makes them unstable both in physiological buffer and in urine. This effect is attributed to pH changes and complexing of calcium by S2O32-and SO42- moiety produced by the test compounds.

  18. Antifoaming materials studies in G.S. (Girlder sulfide) heavy water plants. Chemical stability. Pt. 1

    International Nuclear Information System (INIS)

    As in Girlder sulfide (G.S.) heavy water plants the system is inherently foaming, it is necessary to use antifoaming materials to solve this problem. This work describes the assays and results of some surfactants that can be employed to this purpose, under the corresponding temperature and pressure conditions of the plant. (Author)

  19. Studies of the surface reactivity of metal oxyhydroxides and sulfides with relevance to environmental chemistry

    Science.gov (United States)

    Pierre-Louis, Andro-Marc

    With the benefits of an ever increasing advance of industrialization around the globe come formidable environmental problems. Three environmental problems that have relevance to the research described in this thesis are the 1) buildup of atmospheric CO2 gas through the burning of fossil fuels, 2) eutrophication of aquatic systems, and 3) the acidification of environments from acid mine drainage (AMD) resulting from coal-mining activities. In particular research is presented in this thesis that investigated the surface chemistry of CO2 and phosphate (PO43-) on a suite of environmentally relevant iron oxyhydroxide materials and the chemistry of phospholipid molecules on environmentally relevant iron sulfide surfaces to suppress AMD. To develop a microscopic understanding of the surface chemistry of the different systems, an array of experimental and computational techniques were used in the research. Techniques included X-ray photoelectron spectroscopy, atomic adsorption, X-ray diffraction, scanning transmission microscopy with electron dispersive X-ray spectroscopy (STEM/EDS), ion chromatography (IC), and attenuated total reflectance Fourier transform Infrared (ATR-FTIR). Results from the latter technique were interpreted with the aid of density function theory (DFT) calculations. Iron oxyhydroxides, which consisted of ferrihydrite (FeOOH), goethite (α-FeOOH), ferrimagnetic ferrihydrite (FerriFh), and aluminum-doped iron oxyhydroxide (content from 0-100 mol%) were synthesized and studied before and after exposure to gaseous CO2, CO32-, and PO43- species. FeOOH and mixed Al/Fe oxyhydroxide surfaces showed high affinities for the formation of carbonate and bicarbonate species upon exposure to gaseous CO2. Within the Al/Fe oxyhydroxide circumstance, a low Al level of incorporation in the iron oxyhydroxide structure caused a slight increase in surface area and increase in the amount of oxyanion (e.g., CO32- or PO43-) adsorption up to an Al level of 30 mol%. Significant

  20. Experimental study on liquid immiscibility of lamprophyre-sulfide melt at high temperature and high pressure and its geological significance

    Institute of Scientific and Technical Information of China (English)

    LI Bo; HUANG Zhilong; ZHU Chengming

    2009-01-01

    With lamprophyre and pyrite from the Laowangzhai gold deposit, Yunnan Province, China, as starting materials, and at pressures from 1.5 to 3.0 GPa and temperatures from 1160 to 1560℃, an experimental study was carried out on the liquid immiscibility of lamprophyre-sulfide melt at high temperature and ultra-high pressure in the DS-29A cubic 3600T/6-type high pressure apparatus. Results showed that the liquid immiscibility of lampropyre-sulfide melt in the magmatic system would happen during the early magmatic evolution (high temperature and high pressure conditions) and was controlled by temperature and pressure. The sulfide melt which was separated from the lamprophyric melt would make directional movement in the temperature and pressure field and assemble in the low-temperature and low-pressure region. Because the density of SM is higher than that of the lamprophyric melt, the former would gather together at the bottom of the magma chamber and there would exist a striking boundary between the two melts. On the other hand, the results also suggested that there would be little possibility for lamprophyric magma to carry massive gold, and lamprophyres can't provide many of ore-forming materials (Au) in the processes of gold mineralization.

  1. Silicon-directed rhenium-catalyzed allylic carbaminations and oxidative fragmentations of γ-silyl allylic alcohols.

    Science.gov (United States)

    Chavhan, Sanjay W; Cook, Matthew J

    2014-04-22

    A highly regioselective allylic substitution of β-silyl allylic alcohols has been achieved that provides the branched isomer as a single product. This high level of regiocontrol is achieved through the use of a vinyl silane group that can perform a Hiyama coupling providing 1,3-disubstituted allylic amines. An unusual oxidative fragmentation product was also observed at elevated temperature that appears to proceed by a Fleming-Tamao-type oxidation-elimination pathway. PMID:24677380

  2. Temperature-controlled redox-neutral ruthenium(ii)-catalyzed regioselective allylation of benzamides with allylic acetates.

    Science.gov (United States)

    Manikandan, Rajendran; Jeganmohan, Masilamani

    2016-08-10

    Substituted aromatic amides reacted efficiently with allylic acetates in the presence of a cationic ruthenium complex in ClCH2CH2Cl at room temperature providing ortho allylated benzamides in a highly regioselective manner without any oxidant and base. The whole catalytic reaction occurred in a Ru(ii) oxidation state and thus the oxidation step is avoided. By tuning the reaction temperature, ortho allyl and vinyl benzamides were prepared exclusively. Later, ortho allyl and vinylated benzamides were converted into biologically useful six- and five-membered benzolactones in the presence of HCl. PMID:27456467

  3. Inhibition of sulfide mineral oxidation by surface coating agents: batch and field studies.

    Science.gov (United States)

    Ji, Min-Kyu; Gee, Eun-Do; Yun, Hyun-Shik; Lee, Woo-Ram; Park, Young-Tae; Khan, Moonis Ali; Jeon, Byong-Hun; Choi, Jaeyoung

    2012-08-30

    The potential of several surface coating agents to inhibit the oxidation of metal sulfide minerals from Young-Dong coal mine and the Il-Gwang gold mine was examined by conducting laboratory scale batch experiments and field tests. Powdered pyrite as a standard sulfide mineral and rock samples from two mine outcrops were mixed with six coating agents (KH(2)PO(4), MgO and KMnO(4) as chemical agents, and apatite, cement and manganite as mineral agents) and incubated with oxidizing agents (H(2)O(2) or NaClO). For the observed time period (8 days), Young-Dong coal mine samples exhibited the least sulfate (SO(4)(2-)) production in the presence of KMnO(4) (16%) or cement (4%) while, for Il-Gwang mine samples, the least SO(4)(2-) production was observed in presence of KH(2)PO(4) (8%) or cement (2%) compared to control. Field-scale pilot tests at the Il-Gwang site also showed that addition of KH(2)PO(4) decreased SO(4)(2-) production from 200 to 13 mg L(-1) and it also reduced Cu and Mn from 8 and 3 mg L(-1), respectively to detection limits). The experimental results suggested that the use of surface coating agents is a promising alternative for sulfide oxidation inhibition at acid mine drainage sites. PMID:22727481

  4. Toward Efficient Palladium-Catalyzed Allylic C-H Alkylation

    DEFF Research Database (Denmark)

    Jensen, Thomas; Fristrup, Peter

    2009-01-01

    Recent breakthroughs have proved that direct palladium (II)-catalyzed allylic C-H alkylation can be achieved. This new procedure shows that the inherent requirement for a leaving group in the Tsuji-Trost palladium-catalyzed allylic alkylation can be lifted. These initial reports hold great promise...

  5. [Studies on the structure-activity relationship of allyl substituted oxopyrimidines searching for the novel antagonist or agonist of barbiturates to the sleep mechanism based on the uridine receptor theory--barbituric acid to uridine (part I)].

    Science.gov (United States)

    Yamamoto, Ikuo

    2005-01-01

    Thirty-six allyl substituted oxopyrimidine analogues such as barbituric acid (BA), barbiturates, uracil, thymine, and related derivatives including 13 new compounds were synthesized and their pharmacologic effects ([hypnotic activity, anticonvulsant activity against pentylentetrazol (PTZ)-induced seizures, and LD(50)]) and interactions with the barbiturates were evaluated in mice and rats. The results are briefly and parially summarized as follows. BA prolonged pentobarbital (PB)-induced sleep and had some central depressant effects. N,5,5-triallyl-BA exhibited some hypnotic and anticonvulsant activities, although the other 5,N-allyl-compounds did not show any activity except for allobarbital (AlloB). N-allyl-BA, 5-allyl-BA, N(1),N(3),5-triallyl-BA, N,5,5-triallyl-BA, and N(1),N(3),5,5-tetraallyl-BA also prolonged PB-induced sleep. Interestingly, N,5,5-triallyl-BA was the most potent in the interaction with AlloB, phenobarbital (PheB), amobarbital (AB), PB, and thiopental (TP) but not barbital (B). N(1),N(3),5,5-tetraallyl-BA prolonged AlloB-, PB-, and AB-induced sleep but not B-, PheB-, and TP-induced sleep. N(1),N(3),5-triallyl-B prolonged only PB- and TP-induced sleep. 5,5-diallyl-BA prolonged PheB- and TP-induced sleep. N,5-diallyl-BA prolonged only TP-induced sleep. In contrast, BA and N(1),N(3),5-triallyl-AB tended to antagonize AlloB, AB, and B. N(1),N(3),5,5-tetraallyl-BA also slightly antagonized B, PheB, and TP. 5,5-diallyl-BA antagonized only AB. The prolonging effects of BA, N,5,5-triallyl-BA, and N(1),N(3),5,5-tetraallyl-BA on PB-induced sleep were dose dependent. These results indicate that the position and number of allyl groups substituted on the structure of BA play an important role in their depressant activities. This review deals with the structure-activity relationship of allyl-substituted oxopyrimidines as part of our search for antagonists and agonists of barbiturates as well as their mechanisms of action. PMID:15635282

  6. Sulfide intrusion and detoxification in seagrasses ecosystems

    DEFF Research Database (Denmark)

    Hasler-Sheetal, Harald; Holmer, Marianne

    Sulfide intrusion in seagrasses represents a global threat to seagrasses and thereby an important parameter in resilience of seagrass ecosystems. In contrast seegrasses colonize and grow in hostile sediments, where they are constantly exposed to invasion of toxic gaseous sulfide. Remarkably little...... is known about the strategies of seagrasses to survive sulfide intrusion, their potential detoxification mechanisms and sulfur nutrition in general. By a global review of sulfide intrusion, coupled with a series of field studies and in situ experiments we elucidate sulfide intrusion and different...... strategies of seagrasses to sustain sulfide intrusion. Using stable isotope tracing, scanning electron microscopy with x-ray analysis, tracing sulfur compounds combined with ecosystem parameters we found different spatial, intraspecific and interspecific strategies to cope with sulfidic sediments. 1...

  7. Study on application of biological iron sulfide composites in treating vanadium-extraction wastewater containing chromium (VI) and chromium reclamation.

    Science.gov (United States)

    Xie, Yi-Fei; Li, Xu-Dong; Li, Fu-De

    2013-04-01

    In this study, the Cr(VI)-resistant properties and regeneration characteristics of biological iron sulfide composites were investigated, which consist of sulfate reducing bacteria (SRB) and its in situ synthesized nanosized iron sulfides. Then the application of the composites in treating vanadium-extraction wastewater containing high concentration Cr(VI) and reclaiming Cr were performed. It was found that SRB in composites still survived after being used to treat vanadium-extraction wastewater, which could reduce reaction products Fe3+ and sulphur into Fe2+ and S2 by using them as the electron accepters and thus regenerating biological iron sulfide composites. The SRB also could be resistant to 600 mgl(-1) Cr(VI) and reduce it gradually. Based on the Cr(VI)-resistant properties and regeneration characteristics of the composites, a reduction-regeneration recirculation process for treating vanadium-extraction wastewater and reclamation of Cr was developed. The results indicated that the contaminants in effluent reached the Chinese discharge standard of pollutants for vanadium industry (GB 26452-2011), i.e. the concentration of total Cr(TCr) was less than 0.912 mgl(-1), Cr(VI) was less than 0.017 mgl(-1) and V was less than 0.260 mgl(-1). After 10 cycles of treatment, the Cr2O3 content in sludge reached 41.03%, and the ratio of Cr2O3/FeO was 7.35. The sludge reached the chemical and metallurgical (hydrometallurgy) grade of chromite ore and could be reclaimed. PMID:24620597

  8. Congested C-C Bonds by Pd-Catalyzed Enantioselective Allyl-Allyl Cross-Coupling, A Mechanism-Guided Solution

    OpenAIRE

    Ardolino, Michael J.; Morken, James P.

    2014-01-01

    Under the influence of a chiral bidentate diphosphine ligand, the Pd-catalyzed asymmetric cross-coupling of allylboron reagents and allylic electrophiles establishes 1,5-dienes with adjacent stereocenters in high regio- and stereoselectivity. . A mechanistic study of the coupling utilizing reaction calorimetry and density functional theory analysis suggests that the reaction operates through an inner-sphere 3,3'-reductive elimination pathway, which is both rate- and stereodefining. Coupled wi...

  9. Glutathione-Garlic Sulfur Conjugates: Slow Hydrogen Sulfide Releasing Agents for Therapeutic Applications

    Directory of Open Access Journals (Sweden)

    Ashif Iqbal Bhuiyan

    2015-01-01

    Full Text Available Natural organosulfur compounds (OSCs from Allium sativum L. display antioxidant and chemo-sensitization properties, including the in vitro inhibition of tumor cell proliferation through the induction of apoptosis. Garlic water- and oil-soluble allyl sulfur compounds show distinct properties and the capability to inhibit the proliferation of tumor cells. In the present study, we optimized a new protocol for the extraction of water-soluble compounds from garlic at low temperatures and the production of glutathionyl-OSC conjugates during the extraction. Spontaneously, Cys/GSH-mixed-disulfide conjugates are produced by in vivo metabolism of OSCs and represent active molecules able to affect cellular metabolism. Water-soluble extracts, with (GSGaWS or without (GaWS glutathione conjugates, were here produced and tested for their ability to release hydrogen sulfide (H2S, also in the presence of reductants and of thiosulfate:cyanide sulfurtransferase (TST enzyme. Thus, the TST catalysis of the H2S-release from garlic OSCs and their conjugates has been investigated by molecular in vitro experiments. The antiproliferative properties of these extracts on the human T-cell lymphoma cell line, HuT 78, were observed and related to histone hyperacetylation and downregulation of GAPDH expression. Altogether, the results presented here pave the way for the production of a GSGaWS as new, slowly-releasing hydrogen sulfide extract for potential therapeutic applications.

  10. Glutathione-garlic sulfur conjugates: slow hydrogen sulfide releasing agents for therapeutic applications.

    Science.gov (United States)

    Bhuiyan, Ashif Iqbal; Papajani, Vilma Toska; Paci, Maurizio; Melino, Sonia

    2015-01-01

    Natural organosulfur compounds (OSCs) from Allium sativum L. display antioxidant and chemo-sensitization properties, including the in vitro inhibition of tumor cell proliferation through the induction of apoptosis. Garlic water- and oil-soluble allyl sulfur compounds show distinct properties and the capability to inhibit the proliferation of tumor cells. In the present study, we optimized a new protocol for the extraction of water-soluble compounds from garlic at low temperatures and the production of glutathionyl-OSC conjugates during the extraction. Spontaneously, Cys/GSH-mixed-disulfide conjugates are produced by in vivo metabolism of OSCs and represent active molecules able to affect cellular metabolism. Water-soluble extracts, with (GSGaWS) or without (GaWS) glutathione conjugates, were here produced and tested for their ability to release hydrogen sulfide (H2S), also in the presence of reductants and of thiosulfate:cyanide sulfurtransferase (TST) enzyme. Thus, the TST catalysis of the H2S-release from garlic OSCs and their conjugates has been investigated by molecular in vitro experiments. The antiproliferative properties of these extracts on the human T-cell lymphoma cell line, HuT 78, were observed and related to histone hyperacetylation and downregulation of GAPDH expression. Altogether, the results presented here pave the way for the production of a GSGaWS as new, slowly-releasing hydrogen sulfide extract for potential therapeutic applications. PMID:25608858

  11. Palladium/N-heterocyclic carbene catalysed regio and diastereoselective reaction of ketones with allyl reagents via inner-sphere mechanism.

    Science.gov (United States)

    Bai, Da-Chang; Yu, Fei-Le; Wang, Wan-Ying; Chen, Di; Li, Hao; Liu, Qing-Rong; Ding, Chang-Hua; Chen, Bo; Hou, Xue-Long

    2016-01-01

    The palladium-catalysed allylic substitution reaction is one of the most important reactions in transition-metal catalysis and has been well-studied in the past decades. Most of the reactions proceed through an outer-sphere mechanism, affording linear products when monosubstituted allyl reagents are used. Here, we report an efficient Palladium-catalysed protocol for reactions of β-substituted ketones with monosubstituted allyl substrates, simply by using N-heterocyclic carbene as ligand, leading to branched products with up to three contiguous stereocentres in a (syn, anti)-mode with excellent regio and diastereoselectivities. The scope of the protocol in organic synthesis has been examined preliminarily. Mechanistic studies by both experiments and density functional theory (DFT) calculations reveal that the reaction proceeds via an inner-sphere mechanism-nucleophilic attack of enolate oxygen on Palladium followed by C-C bond-forming [3,3']-reductive elimination. PMID:27283477

  12. STUDY ON GREY FORECASTING MODEL OF COPPER EXTRACTION RATE WITH BIOLEACHING OF PRIMARY SULFIDE ORE

    Institute of Scientific and Technical Information of China (English)

    A.X. Wu; Y. Xi; B.H. Yang; X.S. Chen; H.C. Jiang

    2007-01-01

    A model GM (grey model) (1,1) for forecasting the rate of copper extraction during the bioleaching of primary sulphide ore was established on the basis of the mathematical theory and the modeling process of grey system theory. It was used for forecasting the rate of copper extraction from the primary sulfide ore during a laboratory microbial column leaching experiment. The precision of the forecasted results were examined and modified via "posterior variance examination". The results show that the forecasted values coincide with the experimental values. GM (1,1) model has high forecast accuracy; and it is suitable for simulation control and prediction analysis of the original data series of the processes that have grey characteristics, such as mining, metallurgical and mineral processing, etc. The leaching rate of such copper sulphide ore is low. The grey forecasting result indicates that the rate of copper extraction is approximately 20% even after leaching for six months.

  13. An Ion Microprobe Study of Fractionated Sulfur Isotopes in Hydrothermal Sulfides of the Kaidun Meteorite Breccia

    Science.gov (United States)

    McSween, H. Y., Jr.; Riciputi, L. R.; Paterson, B. A.

    1996-03-01

    The Kaidun breccia contains diverse clasts of enstatite and carbonaceous chondrite, identified by their petrography and oxygen isotopic compositions. One distinctive lithology, classified as CM1 to reflect its CM parentage and highly altered state, contains texturally unusual pyrrhotite needles wrapped in sheaths of phyllosilicate, as well as aggregates and crosscutting veins of pentlandite. The unique textures and associated alteration minerals (serpentine, saponite, melanite garnet, framboidal magnetite) indicate that these sulfides formed in a precursor parent body by reactions with hydrothermal fluids at temperatures as high as 450 degrees C . The alteration conditions recorded by these clasts are extreme in comparison to other carbonaceous chondrites, and coated, jackstraw pyrrhotites are unknown from other meteorites. Thus, it is important to document the reaction products as completely as possible. Here we report the results of in situ analyses of sulfur isotopes in Kaidun pyrrhotite and pentlandite, obtained using a Cameca ims-4f ion microprobe.

  14. An experimental study on the treatment of nude mice with liver carcinoma by intratumoral injection with 188Re rhenium sulfide suspension

    International Nuclear Information System (INIS)

    Objective: To prepare a [188Re] rhenium sulfide suspension and to evaluate its therapeutic effects on liver carcinoma by intratumoral injection. Methods: 30 nude mice bearing SMMC-7721 human liver carcinoma were used for the biodistribution study after intratumoral injection of [188Re] rhenium sulfide suspension or sodium [188Re] perrhenate solution. Another 30 tumor-bearing nude mice were divided into six groups, four groups of them were treated with a 0.1 mL [188Re] rhenium sulfide suspension at doses of 3.7, 7.4, 18.5, 29.6 MBq by a single intratumoral injection. For control studies, the remaining two groups were injected with nonradioactive rhenium sulfide suspension and Hanks' balanced salt solution, respectively. Every injection was repeated 6 days later. Results: The retention percentages of radioactivity (% ID) in tumors injected with [188Re] rhenium sulfide suspension were (90.96 +- 6.63)%, (86.09 +- 22.58)% and (87.62 +- 13.97)% at 1, 24 and 48 h, respectively, which were much higher than retention in normal organs evaluated. In the case of sodium 188Re-perrhenate solution, the % ID values were only (1.66 +- 0.35)%, (0.02 +- 0.01)% and (0.01 +- 0.01)%, respectively. Tumor inhibition ratios were as high as 89% when the peripheral portion of tumor (0.5 - 0.6 cm from center) absorbed an activity share of about 507.6 Gy . Conclusion: Intratumoral injection of [188Re] rhenium sulfide suspension results in significant tumor restraint and it is indicated that this is a highly potential approach to the treatment of hepatic carcinoma

  15. Biotechnological reduction of sulfide in an industrial primary wastewater treatment system: A sustainable and successful case study

    Energy Technology Data Exchange (ETDEWEB)

    Rajamani, S. [Central Leather Research Institute, Madras (India)

    1996-12-31

    The leather industry is an important export-oriented industry in India, with more than 3,000 tanneries located in different clusters. Sodium sulfide, a toxic chemical, is used in large quantities to remove hair and excess flesh from hides and skins. Most of the sodium sulfide used in the process is discharged as waste in the effluent, which causes serious environmental problems. Reduction of sulfide in the effluent is generally achieved by means of chemicals in the pretreatment system, which involves aerobic mixing using large amounts of chemicals and high energy, and generating large volumes of sludge. A simple biotechnological system that uses the residual biosludge from the secondary settling tank was developed, and the commercial-scale application established that more than 90% of the sulfide could be reduced in the primary treatment system. In addition to the reduction of sulfide, foul smells, BOD and COD are reduced to a considerable level. 3 refs., 2 figs., 1 tab.

  16. Chiral allyl silane additions to chiral α-substituted aldehydes

    International Nuclear Information System (INIS)

    Chiral allyl silane 3 reacted with chiral α-methyl-β-siloxy-aldehydes to afford the corresponding 1,4-syn-products with good diastereo-selectivities independent of the absolute stereochemistry of these aldehydes. The best selectivities are observed when the reactions are carried out by trans metallation of the allyl silane 3 using Tin (IV) Chloride in CH2 CL2 at -78 deg C, before addition of the aldehydes. (author)

  17. Zinc Mediated Tandem Fragmentation-Allylation of Methyl 5-Iodopentofuranosides

    DEFF Research Database (Denmark)

    Hyldtoft, Lene; Madsen, Robert

    1999-01-01

    In the presence of zinc and allyl bromide methyl 5-iodopentofuranosides undergo a tandem fragmentation alkylation to give functionalized dienes. These can undergo ring-closing olefin metathesis to produce cyclohexenes which on dihydroxylation give quercitols.......In the presence of zinc and allyl bromide methyl 5-iodopentofuranosides undergo a tandem fragmentation alkylation to give functionalized dienes. These can undergo ring-closing olefin metathesis to produce cyclohexenes which on dihydroxylation give quercitols....

  18. Moessbauer study on microwave synthesized (Cu,Fe) sulfide composites and correlation with natural mineral-cubanite

    International Nuclear Information System (INIS)

    In nature, the mineral 'Cubanite' with composition CuFe2S3 occurs in orthorhombic structure in the matrix of chalcopyrite and pyrrhotite. Synthesis of this mineral in the laboratory conditions has not been reported yet. An attempt to synthesize the orthorhombic Cu-Fe-Sulfide (cubanite) by resistive as well as microwave heating technique is reported. MW-heated sample shows the presence of orthorhombic component along with isocubanite and pyrrhotite. The synthesized samples were studied in details through XRD and Moessbauer spectroscopy. The synthesis process, responsible for different proportions of the minerals, may indicate the conditions of their genesis in nature. Formation of isocubanite (cubic cubanite) seems unavoidable under the conditions of synthesis. The striking indistinguishable character of cubanite and chalcopyrite could be challenged through Moessbauer hyperfine parameter-the hyperfine field of chalcopyrite (∼37 T) being quite different from that of cubanite (∼33 T).

  19. Moessbauer study on microwave synthesized (Cu,Fe) sulfide composites and correlation with natural mineral-cubanite

    Energy Technology Data Exchange (ETDEWEB)

    Pareek, Sarita [University of Rajasthan, High-Pressure Physics Laboratory, Department of Physics (India); Rais, Anwar [Geological Survey of India (India); Tripathi, Amita [J. N. V. University, Moessbauer Lab., Department of Physics (India); Chandra, Usha, E-mail: ushac_jp1@sancharnet.in [University of Rajasthan, High-Pressure Physics Laboratory, Department of Physics (India)

    2008-09-15

    In nature, the mineral 'Cubanite' with composition CuFe{sub 2}S{sub 3} occurs in orthorhombic structure in the matrix of chalcopyrite and pyrrhotite. Synthesis of this mineral in the laboratory conditions has not been reported yet. An attempt to synthesize the orthorhombic Cu-Fe-Sulfide (cubanite) by resistive as well as microwave heating technique is reported. MW-heated sample shows the presence of orthorhombic component along with isocubanite and pyrrhotite. The synthesized samples were studied in details through XRD and Moessbauer spectroscopy. The synthesis process, responsible for different proportions of the minerals, may indicate the conditions of their genesis in nature. Formation of isocubanite (cubic cubanite) seems unavoidable under the conditions of synthesis. The striking indistinguishable character of cubanite and chalcopyrite could be challenged through Moessbauer hyperfine parameter-the hyperfine field of chalcopyrite ({approx}37 T) being quite different from that of cubanite ({approx}33 T).

  20. Allylation of Intraerythrocytic Hemoglobin by Raw Garlic Extracts

    OpenAIRE

    Bonaventura, Joseph; Rodriguez, Eva N.; Beyley, Veronica; Vega, Irving E.

    2010-01-01

    Recent studies have shown that deoxygenated human red blood cells (RBCs) converted garlic-derived polysulfides into hydrogen sulfide, which in turn produced vasorelaxation in aortic ring preparations. The vasoactivity was proposed to occur via glucose- and thiol-dependent acellular reactions. In the present study, we investigated the interaction of garlic extracts with human deoxygenated RBCs and its effect on intracellular hemoglobin molecules. The results showed that garlic extract covalent...

  1. Study on the Size-Dependent Oxidation Reaction Kinetics of Nanosized Zinc Sulfide

    Directory of Open Access Journals (Sweden)

    Qing-Shan Fu

    2014-01-01

    Full Text Available Numerous oxidation problems of nanoparticles are often involved during the preparation and application of nanomaterials. The oxidation rate of nanomaterials is much faster than bulk materials due to nanoeffect. Nanosized zinc sulfide (nano-ZnS and oxygen were chosen as a reaction system. The influence regularities were discussed and the influence essence was elucidated theoretically. The results indicate that the particle size can remarkably influence the oxidation reaction kinetics. The rate constant and the reaction order increase, while the apparent activation energy and the preexponential factor decrease with the decreasing particle size. Furthermore, the logarithm of rate constant, the apparent activation energy and the logarithm of preexponential factor are linearly related to the reciprocal of particle diameter, respectively. The essence is that the rate constant is influenced by the combined effect of molar surface energy and molar surface entropy, the reaction order by the molar surface area, the apparent activation energy, by the molar surface energy, and the preexponential factor by the molar surface entropy. The influence regularities and essence can provide theoretical guidance to solve the oxidation problems involved in the process of preparation and application of nanomaterials.

  2. Study on hydrogen sulfide removal based on bench-scale experiment by bio-trickling filter

    Institute of Scientific and Technical Information of China (English)

    TIAN Shu-lei; ZHANG Lan-he; WANG Qun-hui; WANG Xu-ming; XIE Wei-min

    2007-01-01

    A bench-scale experiment for control of hydrogen sulfide (H2S) emissions was carried out continuously for nearly four months by using bio-trickling filter packed with ZX01 stuffing. The results suggested that the bio-trickling filter had proven excellent performance over substantial operational periods. Removal efficiency of H2S was nearly 100% when volumetric loading of the bio-trickling filter varied from 0.64 g/(m3·h)to 38.20 g/(m3·h) and metabolism products of H2S were mainly composed of SO42-. When inlet concentration of H2S was 250 mg/m3, the optimum gas retention time was 30 s and the optimum spray water not blocked during experiments for nearly four months during which resistance was maintained at relatively lower value, so that the bio-trickling filter need not carry out back washing frequently and can be operated steadily for long-term.

  3. A chemical assessment of the suitability of allyl- iso-propyltelluride as a Te precursor for metal organic vapour phase epitaxy

    Science.gov (United States)

    Hails, Janet E.; Cole-Hamilton, David J.; Stevenson, John; Bell, William; Foster, Douglas F.; Ellis, David

    2001-04-01

    The chemical studies, which led to the testing of allyl- iso-propyltelluride (allylTePr i) as a Te precursor in metal organic vapour phase epitaxy are presented. The pyrolysis in hydrogen of allylTePr i gave products including 1,5-hexadiene, propane and propene. Co-pyrolysis of dimethylcadmium (Me 2Cd) and allylTePr i gave the hydrocarbons expected from the pyrolysis of the individual precursors plus additional hydrocarbons including 2-methylpropane and 1-butene. Plots of percentage decomposition versus temperature, which proved extremely useful in determining the likely growth temperatures for both CdTe and HgTe, showed that allylTePr i is less stable than both Pr 2iTe (di- iso-propyltelluride) and Me 2Cd. The possible role of Hg in the growth of CdTe is also discussed. The chemistry of allylTePr i is well suited for use as an efficient precursor for epitaxial growth of tellurium containing semiconductors since there is very little formation of other organotellurium compounds on pyrolysis.

  4. On the key role of water in the allylic activation catalysed by Pd (II) bisphosphinite complexes

    Indian Academy of Sciences (India)

    Rakesh Kumar Sharma; Ashoka G Samuelson

    2006-11-01

    Palladium and platinum complexes of bisphosphinites and bisphosphines derived from mandelic acid have been prepared and characterized. Their ability to catalyze allylation of imines with allyltributylstannane has been studied. Bisphophinite complexes of Pd (II) are shown to be ideal and they work best in the presence of one equivalent of water. The near neutral conditions employed make the catalysts suitable for a wide variety of substrates.

  5. Tether-directed synthesis of highly substituted oxasilacycles via an intramolecular allylation employing allylsilanes

    Directory of Open Access Journals (Sweden)

    Cox Liam R

    2007-02-01

    Full Text Available Abstract Background Using a silyl tether to unite an aldehyde electrophile and allylsilane nucleophile into a single molecule allows a subsequent Lewis-acid-mediated allylation to proceed in an intramolecular sense and therefore receive all the benefits associated with such processes. However, with the ability to cleave the tether post allylation, a product that is the result of a net intermolecular reaction can be obtained. In the present study, four diastereoisomeric β-silyloxy-α-methyl aldehydes, which contain an allylsilane tethered through the β-carbinol centre, have been prepared, in order to probe how the relative configuration of the two stereogenic centres affects the efficiency and selectivity of the intramolecular allylation. Results Syn-aldehydes, syn-4a and syn-4b, both react poorly, affording all four possible diastereoisomeric oxasilacycle products. In contrast, the anti aldehydes anti-4a and anti-4b react analogously to substrates that lack substitution at the α-site, affording only two of the four possible allylation products. Conclusion The outcome of the reaction with anti-aldehydes is in accord with reaction proceeding through a chair-like transition state (T.S.. In these systems, the sense of 1,3-stereoinduction can be rationalised by the aldehyde electrophile adopting a pseudoaxial orientation, which will minimise dipole-dipole interactions in the T.S. The 1,4-stereoinduction in these substrates is modest and seems to be modulated by the R substituent in the starting material. In the case of the syn-substrates, cyclisation through a chair T.S. is unlikely as this would require the methyl substituent α to the reacting carbonyl group to adopt an unfavourable pseudoaxial position. It is therefore proposed that these substrates react through poorly-defined T.S.s and consequently exhibit essentially no stereoselectivity.

  6. The soft X-ray absorption spectrum of the allyl free radical.

    Science.gov (United States)

    Alagia, M; Bodo, E; Decleva, P; Falcinelli, S; Ponzi, A; Richter, R; Stranges, S

    2013-01-28

    The first experimental study of the X-ray absorption spectrum (XAS) of the allyl free radical, CH(2)CHCH(2), is reported. A supersonic He seeded beam of hyperthermal allyl radicals was crossed by a high resolution synchrotron radiation (SR) in the focus of a 3D ion momentum imaging time-of-flight (TOF) spectrometer to investigate the soft X-ray absorption and fragmentation processes. The XAS, recorded as Total-Ion-Yield (TIY), is dominated by C1s electron excitations from either the central carbon atom, C(C), or the two terminal carbon atoms, C(T), to the frontier orbitals, the semi-occupied-molecular-orbital (SOMO) and the lowest-unoccupied-molecular-orbital (LUMO). All of the intense features in the XAS could only be assigned with the aid of ab initio spectral simulation at the Multi-Configuration Self-Consistent-Field (MCSCF) level of theory, this level being required because of the multi-reference nature of the core-excited state wavefunctions of the open shell molecule. The ionization energies (IEs) of the singlet and triplet states of the C1s ionized allyl radical (XPS) were also calculated at the MCSCF level. PMID:23232557

  7. New biologically active hydrogen sulfide donors.

    Science.gov (United States)

    Roger, Thomas; Raynaud, Francoise; Bouillaud, Frédéric; Ransy, Céline; Simonet, Serge; Crespo, Christine; Bourguignon, Marie-Pierre; Villeneuve, Nicole; Vilaine, Jean-Paul; Artaud, Isabelle; Galardon, Erwan

    2013-11-25

    Generous donors: The dithioperoxyanhydrides (CH3 COS)2 , (PhCOS)2 , CH3 COSSCO2 Me and PhCOSSCO2 Me act as thiol-activated hydrogen sulfide donors in aqueous buffer solution. The most efficient donor (CH3 COS)2 can induce a biological response in cells, and advantageously replace hydrogen sulfide in ex vivo vascular studies. PMID:24115650

  8. Study on Influencing Factors of Ferrous Sulfide Formation%影响硫化亚铁产生的因素实验研究

    Institute of Scientific and Technical Information of China (English)

    修丽群; 穆超; 刘丽丽; 刘帅

    2015-01-01

    随着以蒸汽吞吐为主要手段的热力开采技术的应用,油井套管气中开始出现硫化氢,伴随着热采时间的增加和 SAGD 技术的应用,含硫化氢油井数目不断增加,硫化氢浓度不断升高,产生腐蚀产物——硫化亚铁。硫化亚铁具有自燃性,在常温下与空气中的氧气接触能迅速反应放热而引起自燃。为了避免设备发生硫化亚铁自燃事故,必须对硫化亚铁自燃机理开展深入研究。通过室内试验研究本文发现:常温下,干燥的环境中干燥的 H2S 气体能与铁的氧化物比较容易发生硫化反应。温度、H2S 的湿度、不同的铁氧化物,均对硫化亚铁的生成有重要影响。铁氧化物的含水量不同,其硫化产物 FeS 的量也不同。%During application of the steam stimulation as the thermal mining technology, hydrogen sulphide appears in oil well casing gas. Along with the increase of thermal recovery time and application of SAGD technology, the number of hydrogen sulfide-bearing wells increases, the concentration of hydrogen sulfide is also rising, and ferrous sulfide as corrosion products forms. Ferrous sulfide has the feature of spontaneous combustion, if it contacts with oxygen in air at room temperature, they can quickly react to cause spontaneous combustion. In order to avoid the occurrence of ferrous sulfide self-ignition accident, it is necessary to conduct in-depth research on ferrous sulfide self-ignition mechanism. Laboratory studies show that, under normal temperature, dry H2S gas and iron oxide can react easily in the dry environment. Temperature, H2S humidity and iron oxide have important influence on the formation of ferrous sulfide. If the water content of iron oxide is different, then the quantity of FeS is also different..

  9. Scalable and sustainable electrochemical allylic C–H oxidation

    Science.gov (United States)

    Horn, Evan J.; Rosen, Brandon R.; Chen, Yong; Tang, Jiaze; Chen, Ke; Eastgate, Martin D.; Baran, Phil S.

    2016-05-01

    New methods and strategies for the direct functionalization of C–H bonds are beginning to reshape the field of retrosynthetic analysis, affecting the synthesis of natural products, medicines and materials. The oxidation of allylic systems has played a prominent role in this context as possibly the most widely applied C–H functionalization, owing to the utility of enones and allylic alcohols as versatile intermediates, and their prevalence in natural and unnatural materials. Allylic oxidations have featured in hundreds of syntheses, including some natural product syntheses regarded as “classics”. Despite many attempts to improve the efficiency and practicality of this transformation, the majority of conditions still use highly toxic reagents (based around toxic elements such as chromium or selenium) or expensive catalysts (such as palladium or rhodium). These requirements are problematic in industrial settings; currently, no scalable and sustainable solution to allylic oxidation exists. This oxidation strategy is therefore rarely used for large-scale synthetic applications, limiting the adoption of this retrosynthetic strategy by industrial scientists. Here we describe an electrochemical C–H oxidation strategy that exhibits broad substrate scope, operational simplicity and high chemoselectivity. It uses inexpensive and readily available materials, and represents a scalable allylic C–H oxidation (demonstrated on 100 grams), enabling the adoption of this C–H oxidation strategy in large-scale industrial settings without substantial environmental impact.

  10. Scalable and sustainable electrochemical allylic C-H oxidation.

    Science.gov (United States)

    Horn, Evan J; Rosen, Brandon R; Chen, Yong; Tang, Jiaze; Chen, Ke; Eastgate, Martin D; Baran, Phil S

    2016-05-01

    New methods and strategies for the direct functionalization of C-H bonds are beginning to reshape the field of retrosynthetic analysis, affecting the synthesis of natural products, medicines and materials. The oxidation of allylic systems has played a prominent role in this context as possibly the most widely applied C-H functionalization, owing to the utility of enones and allylic alcohols as versatile intermediates, and their prevalence in natural and unnatural materials. Allylic oxidations have featured in hundreds of syntheses, including some natural product syntheses regarded as "classics". Despite many attempts to improve the efficiency and practicality of this transformation, the majority of conditions still use highly toxic reagents (based around toxic elements such as chromium or selenium) or expensive catalysts (such as palladium or rhodium). These requirements are problematic in industrial settings; currently, no scalable and sustainable solution to allylic oxidation exists. This oxidation strategy is therefore rarely used for large-scale synthetic applications, limiting the adoption of this retrosynthetic strategy by industrial scientists. Here we describe an electrochemical C-H oxidation strategy that exhibits broad substrate scope, operational simplicity and high chemoselectivity. It uses inexpensive and readily available materials, and represents a scalable allylic C-H oxidation (demonstrated on 100 grams), enabling the adoption of this C-H oxidation strategy in large-scale industrial settings without substantial environmental impact. PMID:27096371

  11. Transition metal catalysed Grignard-like allylic activation across tetragonal tin(II) oxide

    Indian Academy of Sciences (India)

    Pradipta Sinha; Moloy Banerjee; Abhijit Kundu; Sujit Roy

    2002-08-01

    The reaction of allyl halide and a carbonyl compound under the aegis of tetragonal tin(II) oxide and catalytic 8, 10 metal complexes provides the corresponding homoallylic alcohol, via a novel allyl tin intermediate.

  12. A convenient procedure for the synthesis of allyl and benzyl ethers from alcohols and phenols

    Indian Academy of Sciences (India)

    H Surya Prakash Rao; S P Senthilkumar

    2001-06-01

    Allyl and benzyl ethers of alcohols can be prepared conveniently and in high yield with allyl and benzyl bromide in the presence of solid potassium hydroxide without use of any solvent. Phenols can be converted to allyl ethers but are inert to benzylation under above conditions.

  13. 40 CFR 721.7000 - Polymer of disodium maleate, allyl ether, and ethylene oxide.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Polymer of disodium maleate, allyl... New Uses for Specific Chemical Substances § 721.7000 Polymer of disodium maleate, allyl ether, and... substance identified generically as a polymer of disodium maleate, allyl ether, and ethylene oxide...

  14. Study of benzotriazole as corrosion inhibitors of carbon steel in chloride solution containing hydrogen sulfide using electrochemical impedance spectroscopy (EIS)

    International Nuclear Information System (INIS)

    Corrosion and inhibition studies on API 5LX65 carbon steel in chloride solution containing various concentrations of benzotriazole has been conducted at temperature of 70°C using Electrochemical Impedance Spectroscopy (EIS). Corroded carbon steel surface with and without inhibitor have been observed using X-ray Diffraction (XRD), Scanning Electron Microscope (SEM), and Energy Dispersive Spectroscopy (EDS). The objectives of this research are to study the performance of benzotriazole as corrosion inhibitors. The experimental results of carbon steel corrosion in 3.5% NaCl solution containing 500 mg/l H2S at different BTAH concentrations showed that corrosion rate of carbon steel decreases with increasing of BTAH concentrations from 0 to 10 mmol/l. The inhibition efficiency of BTAH was found to be affected by its concentration. The optimum efficiency obtained of BTAH is 93% at concentration of 5 mmol/l. The result of XRD and EDS analysis reveal the iron sulfide (FeS) formation on corroded carbon steel surface without inhibitor. The EDS spectrum show the Nitrogen (N) bond on carbon steel surface inhibited by BTAH

  15. Measurement of dissolved sulfide in geothermal condensate

    Energy Technology Data Exchange (ETDEWEB)

    Chang, D.P.Y.; Corsi, R.L.; McNeece, C.

    1985-01-01

    The objective of this study was to develop a reliable method for determining the concentration of sulfide ions in laboratory solutions and in field samples containing geothermal condensate. A method based upon a sulfide selective ion electrode has been tested successfully on both. The method is straightforward to apply, involving collection of filtered samples into a sulfide anti-oxidant buffer (SAOB), subsequent measurement by electrodes and comparison with a calibration curve prepared from solutions containing known concentrations of sulfide ions. The importance of filtering the samples was demonstrated by a marked reduction of electrode potential after sample filtration. For replicate solutions of known composition containing greater than 1 x 10/sup -6/ M (0.032 ppm) of dissolved sulfide the estimated accuracy of the method was about 5%. For geothermal condensate of unknown composition, the mean of replicate samples was estimated to be within about 20% of the true value.

  16. Direct activation of allylic alcohols in palladium catalyzed coupling reactions

    OpenAIRE

    Gümrükçü, Y.

    2014-01-01

    The direct use of allylic alcohols in substitution reactions without pre-activation of the hydroxyl-group into a better leaving group or the use of additional stoichiometric in situ activators remains challenging due to the poor leaving group ability of the hydroxyl-group. Hence, it is important to develop new methods to activate (bio-mass derived) allyl-alcohols, which allow ‘green’ chemical processes for a broad substrate range. This may have a considerable impact on the methodology for fin...

  17. Iridium-Catalyzed Selective Isomerization of Primary Allylic Alcohols.

    Science.gov (United States)

    Li, Houhua; Mazet, Clément

    2016-06-21

    This Account presents the development of the iridium-catalyzed isomerization of primary allylic alcohols in our laboratory over the past 8 years. Our initial interest was driven by the long-standing challenge associated with the development of a general catalyst even for the nonasymmetric version of this seemingly simple chemical transformation. The added value of the aldehyde products and the possibility to rapidly generate molecular complexity from readily accessible allylic alcohols upon a redox-economical isomerization reaction were additional sources of motivation. Certainly influenced by the success story of the related isomerization of allylic amines, most catalysts developed for the selective isomerization of allylic alcohols were focused on rhodium as a transition metal of choice. Our approach has been based on the commonly accepted precept that hydrogenation and isomerization are often competing processes, with the latter being usually suppressed in favor of the former. The cationic iridium complexes [(Cy3P)(pyridine)Ir(cod)]X developed by Crabtree (X = PF6) and Pfaltz (X = BArF) are usually considered as the most versatile catalysts for the hydrogenation of allylic alcohols. Using molecular hydrogen to generate controlled amounts of the active form of these complexes but performing the reaction in the absence of molecular hydrogen enabled deviation from the typical hydrogenation manifold and favored exclusively the isomerization of allylic alcohols into aldehydes. Isotopic labeling and crossover experiments revealed the intermolecular nature of the process. Systematic variation of the ligand on the iridium center allowed us to identify the structural features beneficial for catalytic activity. Subsequently, three generations of chiral catalysts have been investigated and enabled us to reach excellent levels of enantioselectivity for a wide range of 3,3-disubstituted aryl/alkyl and alkyl/alkyl primary allylic alcohols leading to β-chiral aldehydes. The

  18. Study and modeling of the evolution of gas-liquid partitioning of hydrogen sulfide in model solutions simulating winemaking fermentations.

    Science.gov (United States)

    Mouret, Jean-Roch; Sablayrolles, Jean-Marie; Farines, Vincent

    2015-04-01

    The knowledge of gas-liquid partitioning of aroma compounds during winemaking fermentation could allow optimization of fermentation management, maximizing concentrations of positive markers of aroma and minimizing formation of molecules, such as hydrogen sulfide (H2S), responsible for defects. In this study, the effect of the main fermentation parameters on the gas-liquid partition coefficients (Ki) of H2S was assessed. The Ki for this highly volatile sulfur compound was measured in water by an original semistatic method developed in this work for the determination of gas-liquid partitioning. This novel method was validated and then used to determine the Ki of H2S in synthetic media simulating must, fermenting musts at various steps of the fermentation process, and wine. Ki values were found to be mainly dependent on the temperature but also varied with the composition of the medium, especially with the glucose concentration. Finally, a model was developed to quantify the gas-liquid partitioning of H2S in synthetic media simulating must to wine. This model allowed a very accurate prediction of the partition coefficient of H2S: the difference between observed and predicted values never exceeded 4%. PMID:25763810

  19. Study of structural, optical and photoluminescence properties of indium-doped zinc sulfide thin films for optoelectronic applications

    Science.gov (United States)

    Jrad, Abdelhak; Ben Nasr, Tarek; Turki-Kamoun, Najoua

    2015-12-01

    In the present work, we have deposited indium-doped zinc sulfide (ZnS:In) thin films by chemical bath deposition technique (CBD). The structural properties studied by X-ray diffraction indicate that ZnS:In has a cubic structure with an average crystallite size 4.7-11.0 nm. Transmission and reflection spectra reveal the presence of interference fringes indicating thickness uniformity and surface homogeneity of deposited material. All the films were transparent in the visible and infrared regions (⩾60%), which allows us to use this material as an optical window or a buffer layer in solar cells. The obtained band gap energy Eg is in the range of 3.70-3.76 eV. The refractive index and thickness of ZnS:In thin films was calculated using envelope method. The variation of the refractive index along the Cauchy distribution was observed in all ZnS:In thin films. The analysis of the refractive index data through the Wemple-DiDomenico model leads to the single oscillator energy (E0) and the dispersion energy (Ed).

  20. The effect of sulfide inhibition on the ANAMMOX process.

    Science.gov (United States)

    Jin, Ren-Cun; Yang, Guang-Feng; Zhang, Qian-Qian; Ma, Chun; Yu, Jin-Jin; Xing, Bao-Shan

    2013-03-01

    The feasibility of anaerobic ammonium oxidation (ANAMMOX) process to treat wastewaters containing sulfide was studied in this work. Serum bottles were used as experimental containers in batch tests to analyze the short-term response of the ANAMMOX process under sulfide stress. The IC(50) of sulfide-S for ANAMMOX biomass was substrates-dependent and was calculated to be 264 mg L(-1) at an initial total nitrogen level of 200 mg L(-1) (molar ratio of ammonium and nitrite was 1:1). The long-term effects and the performance recovery under sulfide stress were continuously monitored and evaluated in an upflow anaerobic sludge blanket reactor. The performance of the ANAMMOX system was halved at an sulfide-S level of 32 mg L(-1) within 13 days; however, the nitrogen removal rate (NRR) decreased by only 17.2% within 18 days at an sulfide-S concentration of 40 mg L(-1) after long-time acclimatization of sludge in the presence of sulfide. The ANAMMOX performance recovered under sulfide-S level of 8 mg L(-1) with a steady NRR increasing speed, linear relationship between the NRR and operation time. The synchronic reduce in the specific ANAMMOX activity and the biomass extended the apparent doubling time of the nitrogen removal capacity and decreased biomass growth rate. PMID:23273856

  1. Highly Enantioselective Formation of α-Allyl-α-Arylcyclopentanones via Pd-Catalysed Decarboxylative Asymmetric Allylic Alkylation.

    Science.gov (United States)

    Akula, Ramulu; Doran, Robert; Guiry, Patrick J

    2016-07-11

    A highly enantioselective Pd-catalysed decarboxylative asymmetric allylic alkylation of cyclopentanone derived α-aryl-β-keto esters employing the (R,R)-ANDEN-phenyl Trost ligand has been developed. The product (S)-α-allyl-α-arylcyclopentanones were obtained in excellent yields and enantioselectivities (up to >99.9 % ee). This represents one of the most highly enantioselective formations of an all-carbon quaternary stereogenic center reported to date. This reaction was demonstrated on a 4.0 mmol scale without any deterioration of enantioselectivity and was exploited as the key enantioselective transformation in an asymmetric formal synthesis of the natural product (+)-tanikolide. PMID:27191198

  2. Se, As, Mo, Ag, Cd, In, Sb, Pt, Au, Tl, Re traces in biogenic and abiogenic sulfides from Black Shales (Selwyn Basin, Yukon territories, Canada): A nuclear microprobe study

    International Nuclear Information System (INIS)

    Black shales can be an important source of rare metals such as Cu, Ag, As, Mo, Se, Tl, Cd, platinum group elements (PGE) and gold (Pasava et al., Econ. Geol. 91 (1996) 63). However, especially in the case of noble metals, carriers such as discrete minerals could not be identified. This nuclear microprobe study brings new data on the partition of rare metals in Fe-, Fe (Ni)-, Ni- (Fe)-, Ni- and Zn-sulfides from the Ni-Zn-Mo-PGE mineralized marin black shales (Selwyn Basin, Yukon Territories). Sulfides are present as mineralized vestimentiferan tube-worms which are pyritized. Fluid-mineral interaction led to transformation of these biogenic Fe-sulfides successively to Fe-Ni- and Ni-Fe-sulfides which is indicated by increasing Se contents. Ni-sulfides which are interstital to the tube worms represent remobilized material, they are richest in Se. Several tens to thousands ppm of Cu, Zn, As, Se, Mo were located in the biomineralized and transformed tube worms. Antimony was located in Fe-Ni and Ni-, and Zn sulfides and Ag was present in Fe-Ni and Ni-Fe-sulfides. Pt and Au can also be related to submicron-sized inclusions in Fe-Ni sulfides. Hydrothermal fluids (at least 250 deg. C) precipitated silica around tube worms, intercalating submicron-sized sphalerites. Larger Zn-sulfides contain about 5000 ppm Cd and locally about 60 ppm In. Ba-rich K-feldspar contains Cl-rich Ag-Cd alloys

  3. Textural, mineralogical and stable isotope studies of hydrothermal alteration in the main sulfide zone of the Great Dyke, Zimbabwe and the precious metals zone of the Sonju Lake Intrusion, Minnesota, USA

    Science.gov (United States)

    Li, C.; Ripley, E.M.; Oberthur, T.; Miller, J.D., Jr.; Joslin, G.D.

    2008-01-01

    Stratigraphic offsets in the peak concentrations of platinum-group elements (PGE) and base-metal sulfides in the main sulfide zone of the Great Dyke and the precious metals zone of the Sonju Lake Intrusion have, in part, been attributed to the interaction between magmatic PGE-bearing base-metal sulfide assemblages and hydrothermal fluids. In this paper, we provide mineralogical and textural evidence that indicates alteration of base-metal sulfides and mobilization of metals and S during hydrothermal alteration in both mineralized intrusions. Stable isotopic data suggest that the fluids involved in the alteration were of magmatic origin in the Great Dyke but that a meteoric water component was involved in the alteration of the Sonju Lake Intrusion. The strong spatial association of platinum-group minerals, principally Pt and Pd sulfides, arsenides, and tellurides, with base-metal sulfide assemblages in the main sulfide zone of the Great Dyke is consistent with residual enrichment of Pt and Pd during hydrothermal alteration. However, such an interpretation is more tenuous for the precious metals zone of the Sonju Lake Intrusion where important Pt and Pd arsenides and antimonides occur as inclusions within individual plagioclase crystals and within alteration assemblages that are free of base-metal sulfides. Our observations suggest that Pt and Pd tellurides, antimonides, and arsenides may form during both magmatic crystallization and subsolidus hydrothermal alteration. Experimental studies of magmatic crystallization and hydrothermal transport/deposition in systems involving arsenides, tellurides, antimonides, and base metal sulfides are needed to better understand the relative importance of magmatic and hydrothermal processes in controlling the distribution of PGE in mineralized layered intrusions of this type. ?? Springer-Verlag 2007.

  4. Sulfonium-based Ionic Liquids Incorporating the Allyl Functionality

    Directory of Open Access Journals (Sweden)

    Paul J. Dyson

    2007-04-01

    Full Text Available A series of sulfonium halides bearing allyl groups have been prepared andcharacterized. Anion metathesis with Li[Tf2N] and Ag[N(CN2] resulted in sulfonium-basedionic liquids which exhibit low viscosities at room temperature. The solid state structure ofone of the halide salts was determined by single crystal X-ray diffraction.

  5. Design of the passive personal dosimeter for miners using an allyl diglycol carbonate plastic. Phase 1

    International Nuclear Information System (INIS)

    The report summarizes the results of the feasibility study on the design and development of a passive personal dosimeter incorporating an allyl diglycol carbonate plastic (CR39) detector, for use by uranium miners. Based upon the feasibility study, a passive personal dosimeter using a capacitor-type electrostatic enhancement device has been designed. Preliminary tests indicate that the prototype could be used in the mine environment to differentiate radon and thoron daughters with a detection efficiency comparable to that of a typical active device. Further study is required, however, into the possible influence in the mine environment of local variations in charged fraction, upon the calibration of this dosimeter

  6. EQCM Study of Influence of Anion Nature on Electrochemical Reduction of Bismuth Sulfide in Nickel Plating Solution

    Directory of Open Access Journals (Sweden)

    Loreta TAMAŠAUSKAITĖ-TAMAŠIŪNAITĖ

    2011-03-01

    Full Text Available The influence of anion nature on the reduction of bismuth sulfide film deposited on gold using the successive ionic layer adsorption and reaction method in solutions containing Ni2+ ions has been investigated by electrochemical quartz crystal microbalance combined with cyclic voltammetry and X-ray photoelectron spectroscopy. It has been determined that the reduction of bismuth sulfide film in the nickel plating solution depends on the anion nature: larger cathodic current and mass changes (Dƒ are observed in the solution containing acetate anion as compared to those in the solution containing sulfate anion. As the reduction of bismuth sulfide film in the background solutions depends on the nature of anion, it influences the cathodic reduction of Ni2+ ions prior to OPD of Ni. A greater current and mass change (Dƒ is conditioned by simultaneously occurring reduction of bismuth sulfide film when the film is reduced in the acetate nickel plating electrolyte in contrast to that in the sulfate one.http://dx.doi.org/10.5755/j01.ms.17.1.244

  7. Study of atomic layer deposition of indium oxy-sulfide films for Cu(In,Ga)Se2 solar cells

    International Nuclear Information System (INIS)

    This paper explores the growth mechanism of plasma enhanced atomic layer deposition of In2(S,O)3 films. The films were deposited using indium acetylacetonate (In(acac)3), hydrogen sulfide (H2S) and Ar/O2 plasma as oxygen precursor. The films were characterized using X-ray reflectometry, spectrophotometry, energy dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy. To understand the growth mechanism and especially the interactions between Ar/O2 plasma and In2(S,O)3 growing film, in-situ analyses were performed using quadrupole mass spectrometry. In-situ qualitative analysis revealed good correlation between the species detected in vapor phase and thin film properties. High concentrations of atomic and molecular oxygen were measured in the vapor phase during O2 plasma pulses. Significant decrease of these species could be observed by varying the plasma power from 2600 to 300 W, while the optical band gap remained at high values (> 2.6 eV). The analysis of the O2-free/Ar plasma process showed that some of these oxygen species originate either from the indium precursor or from the substrate surface. This study explains the high oxygen content of the films, and allows us to reduce and control it. Generally, this report provides keys to understand the effect of plasma reactivity for the elaboration of oxide based materials. - Highlights: • In2(S,O)3 films were synthesized by plasma enhanced atomic layer deposition. • Growth mechanism was studied via gas phase analysis by Quadrupole Mass Spectrometry. • Good correlation between the vapor phase species and thin films properties was observed. • The film compositions and band gaps can be controlled by varying the plasma power

  8. Impact history of the Chelyabinsk meteorite: Electron microprobe and LA-ICP-MS study of sulfides and metals

    Science.gov (United States)

    Andronikov, A. V.; Andronikova, I. E.; Hill, D. H.

    2015-12-01

    Electron microprobe and LA-ICP-MS study of sulfides and metals from two fragments of the LL5 Chelyabinsk meteorite were conducted. The fragments are impact breccias, one fragment contains both chondritic and shock vein lithologies, and the other contains shock-darkened chondritic clasts and vesicular impact melts. The chondritic lithology and shock veins display very similar opaque mineral compositions. The mineral compositions in the impact-melt breccias are distinctly different. The brecciated state of the Chelyabinsk meteorite suggests strong involvement of shock-related processes during the evolution of the parent body. Multiple heavy impact events occurred on the parent asteroid and on the Chelyabinsk meteoroid itself over the time period from ca. 4.5 Ga until ca. 1.2 Ma. The shock veins were produced in situ on the parent body. The impact-melt breccias could have formed because of the dramatic impact to the parent LL-chondrite body that could be partly disintegrated. The fragment containing shock-darkened chondritic clasts and vesicular impact melt lithologies preserves a record of melting, volatilization, partial degassing, and quenching of the molten material. The abundance and size (up to 1 mm) of the vesicles suggest that the impact melt must have been buried at some depth after formation. After impact and subsequent melting occurred, the impact-induced pressure on the shallow asteroid interior was released that caused "boiling" of volatiles and generation of S-rich bubbles. Such an impact excavated down to depths of the body generating multiple fragments with complicated histories. These fragments reaccumulated into a gravitational aggregate and formed the parental meteoroid for the Chelyabinsk meteorite.

  9. Phase Engineering of 2D Tin Sulfides.

    OpenAIRE

    Mutlu, Z; Wu, RJ; Wickramaratne, D.; Shahrezaei, S; Liu, C; Temiz, S; Patalano, A; M Ozkan; Lake, RK; Mkhoyan, KA; Ozkan, CS

    2016-01-01

    Tin sulfides can exist in a variety of phases and polytypes due to the different oxidation states of Sn. A subset of these phases and polytypes take the form of layered 2D structures that give rise to a wide host of electronic and optical properties. Hence, achieving control over the phase, polytype, and thickness of tin sulfides is necessary to utilize this wide range of properties exhibited by the compound. This study reports on phase-selective growth of both hexagonal tin (IV) sulfide SnS2...

  10. Studies on the Tolerating Mechanism for Sulfide in Urechis unicinctus ( Echiura : Urechidae) ——Cytological Observation on Urechis unicinctus in Different Hydrogen Sulfide Environment

    Institute of Scientific and Technical Information of China (English)

    张志峰; 邵明瑜; 康庆浩; 金在敏

    2003-01-01

    This study on the cytological changes of the body wall, aspiratory intestine and crissalbursa in Urechis unicinctus by light microscope (LM) and transmission electron microscope (TEM)showed that the difference between the body wall and the natural environment rich in H2 S was notobvious; that the wall color of the aspiratory intestine in H2 S rich environment changed from normalsemitransparency to dark brown; that its epithelia were disassembled and the electron density of itscytoplasm matrix was lower; and that in H2 S rich enviromnent many basophilic granules occurred inthe epithelia of the crissal bursa. Granules with single membrane and myelinefingure were foundwith TEM.

  11. First-Principles Studies of Transition Metal Oxides and Sulfides in Electrochemical Energy Storage Applications

    OpenAIRE

    Liu, Chi-Ping

    2015-01-01

    Unlike batteries, electrochemical supercapacitors require not only high energy density, but also very high rates of charge and ionic transport. In this thesis, first-principles calculations, such as Density Functional Theory (DFT), Molecular Dynamics (MD), and Monte Carlo (MC) are applied to study charge storage mechanisms and factors that affect ion intercalation / diffusion in transition metal compounds (Nb2O5, WO3, and MoS2).Recent experimental results show that niobium oxide exhibits an o...

  12. Stability and aging studies of lead sulfide quantum dot films: Photoabsorption, morphology, and chemical state characteristics

    International Nuclear Information System (INIS)

    The stability of colloidal PbS quantum dot (QD) films deposited on glass substrates was studied over a short term and a long term periods, when left unprotected in air under ambient conditions. Two deposition approaches were used, traditional solvent deposition method (SDM) and supercritical fluid CO2 deposition (SFD). To track possible changes to the QDs over time, near infrared (NIR) spectrometry, X-ray photoelectron spectroscopy (XPS), powder X-ray diffraction (XRD), transmission electron microscopy (TEM), and optical microscopy, were employed. Evidence points towards initial oxidation-induced shrinking of the active QD volume causing a blue shift of the absorption over the first four months, and then experiencing competition from oxidation and sintering/ripening of the QDs, resulting in a red shift. The presented studies have important consequences for the long term reliability of light emitters based on PbS QDs. - Highlights: • The optical and morphological stability of colloidal PbS QD films deposited on glass substrates was characterized. • Optical microscopy, TEM, NIR, XPS and XRD were used to characterize the QD films. • Two QD deposition approaches were compared: traditional solvent deposition and supercritical fluid CO2 deposition. • The study examined the QD stability over a short term and a long term periods. • The PbS QD characteristics were found to be affected by two simultaneous processes, oxidation and sintering/ripening

  13. Functional Analysis of Three Sulfide:Quinone Oxidoreductase Homologs in Chlorobaculum tepidum▿ †

    OpenAIRE

    Chan, Leong-Keat; Morgan-Kiss, Rachael M; Hanson, Thomas E.

    2008-01-01

    Sulfide:quinone oxidoreductase (SQR) catalyzes sulfide oxidation during sulfide-dependent chemo- and phototrophic growth in bacteria. The green sulfur bacterium Chlorobaculum tepidum (formerly Chlorobium tepidum) can grow on sulfide as the sole electron donor and sulfur source. C. tepidum contains genes encoding three SQR homologs: CT0117, CT0876, and CT1087. This study examined which, if any, of the SQR homologs possess sulfide-dependent ubiquinone reduction activity and are required for gro...

  14. Thermophysical properties and reaction kinetics of γ-irradiated poly allyl diglycol carbonates nuclear track detector

    Science.gov (United States)

    Elmaghraby, Elsayed K.; Seddik, Usama

    2015-07-01

    Kinetic thermogravimetric technique was used to study the effect of gamma irradiation on the poly allyl diglycol carbonates (PADC) within the dose range from 50 to ? Gy. The approach of Coats-Redfern was used to analyze the data. Results showed that low doses around 50 Gy make the polymer slightly more resistive to heat treatment. Higher radiation doses cause severe effects in the samples accompanied by the formation of lower molecular mass species and consequent crosslinking. Results support the domination of re-polymerization and crosslinking for the γ radiation interaction PADC at dose below about ? Gy, while the situation is inverted above ? Gy in which chain secession dominates.

  15. Allyl Isothiocyanate Increases MRP1 Function and Expression in a Human Bronchial Epithelial Cell Line

    OpenAIRE

    Dian-lei Wang; Chen-yin Wang; Yin Cao; Xian Zhang; Xiu-hua Tao; Li-li Yang; Jin-pei Chen; Shan-shan Wang; Ze-geng Li

    2014-01-01

    Multidrug resistance-associated protein 1 (MRP1), a member of the ATP-binding cassette (ABC) superfamily of transporters, plays an important role in normal lung physiology by protecting cells against oxidative stress and toxic xenobiotics. The present study investigates the effects of allyl isothiocyanate (AITC) on MRP1 mRNA and MRP1 protein expression and transporter activity in the immortalised human bronchial epithelial cell line 16HBE14o-. MRP1 mRNA and MRP1 protein expression in 16HBE14o...

  16. Mechanistic Investigation of Palladium–Catalyzed Allylic C–H Activation

    DEFF Research Database (Denmark)

    Engelin, Casper Junker; Jensen, Thomas; Rodríguez-Rodríguez, Sergio;

    2013-01-01

    The mechanism for the palladium–catalyzed allylic C–H activation was investigated using a combination of experimental and theoretical methods. A Hammett study revealed a buildup of a partial negative charge in the rate-determining step, while determination of the kinetic isotope effect (KIE...... acetate acts as a base in an intramolecular fashion during the C–H activation step. The re-oxidation of palladium was found to reach a similar energy level as that of the C–H activation. Calculations of turnover frequencies (TOF) for the entire catalytic cycle for the C–H alkylation were used to acquire a...

  17. First-principles study of structures and electronic properties of cadmium sulfide clusters

    Institute of Scientific and Technical Information of China (English)

    Chu He-Ying; Liu Zhao-Xia; Qiu Guo-Li; Kong De-Guo; Wu Si-Xin; Li Yun-Cai; Du Zu-Liang

    2008-01-01

    The lowest-energy structures and the electronic properties of CdnSn(n=1-8) clusters have been studied by using density-functional theory simulating package DMol3 in the generalized gradient approximation (GGA). The ring-like structures are the lowest-energy configurations for n=2,3 and the three-dimensional spheroid configurations for n=4-8. The three-dimensional structures may be considered as being built from the Cd2S2 and Cd3S3 rings. Compared to the previous reports, we have found the more stable structures for CdnSn(n=7,8). Calculations show that the magic numbers of CdnSn(n=1-8) clusters are n=3 and 6. As cluster size increases, the properties of CdnSn clusters tend to bulk-like ones in binding energy per CdS unit and Mulliken atomic charge, obtained by comparing with the calculated results of the wurtzite and zinc blende CdS for the same simulating parameters.

  18. Branching Out: Rhodium-Catalyzed Allylation with Alkynes and Allenes.

    Science.gov (United States)

    Koschker, Philipp; Breit, Bernhard

    2016-08-16

    We present a new and efficient strategy for the atom-economic transformation of both alkynes and allenes to allylic functionalized structures via a Rh-catalyzed isomerization/addition reaction which has been developed in our working group. Our methodology thus grants access to an important structural class valued in modern organic chemistry for both its versatility for further functionalization and the potential for asymmetric synthesis with the construction of a new stereogenic center. This new methodology, inspired by mechanistic investigations by Werner in the late 1980s and based on preliminary work by Yamamoto and Trost, offers an attractive alternative to other established methods for allylic functionalization such as allylic substitution or allylic oxidation. The main advantage of our methodology consists of the inherent atom economy in comparison to allylic oxidation or substitution, which both produce stoichiometric amounts of waste and, in case of the substitution reaction, require prefunctionalization of the starting material. Starting out with the discovery of a highly branched-selective coupling reaction of carboxylic acids with terminal alkynes using a Rh(I)/DPEphos complex as the catalyst system, over the past 5 years we were able to continuously expand upon this chemistry, introducing various (pro)nucleophiles for the selective C-O, C-S, C-N, and C-C functionalization of both alkynes and the double-bond isomeric allenes by choosing the appropriate rhodium/bidentate phosphine catalyst. Thus, valuable compounds such as branched allylic ethers, sulfones, amines, or γ,δ-unsaturated ketones were successfully synthesized in high yields and with a broad substrate scope. Beyond the branched selectivity inherent to rhodium, many of the presented methodologies display additional degrees of selectivity in regard to regio-, diastereo-, and enantioselective transformations, with one example even proceeding via a dynamic kinetic resolution. Many advances

  19. Mesostructured metal germanium sulfides

    Energy Technology Data Exchange (ETDEWEB)

    MacLachlan, M.J.; Coombs, N.; Bedard, R.L.; White, S.; Thompson, L.K.; Ozin, G.A.

    1999-12-29

    A new class of mesostructured metal germanium sulfide materials has been prepared and characterized. The synthesis, via supramolecular assembly of well-defined germanium sulfide anionic cluster precursors and transition-metal cations in formamide, represents a new strategy for the formation of this class of solids. A variety of techniques were employed to examine the structure and composition of the materials. Structurally, the material is best described as a periodic mesostructured metal sulfide-based coordination framework akin to periodic hexagonal mesoporous silica, MCM-41. At the molecular scale, the materials strongly resemble microstructured metal germanium sulfides, in which the structure of the [Ge{sub 4}S{sub 10}]{sup 4{minus}} cluster building-blocks are intact and linked via {mu}-S-M-S bonds. Evidence for a metal-metal bond in mesostructured Cu/Ge{sub 4}S{sub 10} is also provided.

  20. Corrosion Study of Super Ferritic Stainless Steel UNS S44660 (26Cr-3Ni-3Mo) and Several Other Stainless Steel Grades (UNS S31603, S32101, and S32205) in Caustic Solution Containing Sodium Sulfide

    Science.gov (United States)

    Chasse, Kevin R.; Singh, Preet M.

    2013-11-01

    Electrochemical techniques, scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS) were used in this study to show how the corrosion mechanism of several commercial grades of stainless steel in hot caustic solution is strongly influenced by the presence of sodium sulfide. Experimental results from super ferritic stainless steel UNS S44660 (26Cr-3Ni-3Mo) were compared to austenitic stainless steel UNS S31603, lean duplex stainless steel (DSS) UNS S32101, and standard DSS UNS S32205 in caustic solution, with and without sodium sulfide, at 443 K (170 °C). Weight loss measurements indicated that corrosion rates of UNS44660 were much lower than the other grades of stainless steel in the presence of the sodium sulfide. Potentiodynamic polarization and linear polarization resistance measurements showed that the electrochemical behavior was altered by the adhesion of sulfur species, which reduced the polarization resistances and increased the anodic current densities. SEM and XPS results imply that the surface films that formed in caustic solution containing sodium sulfide were defective due to the adsorption of sulfide, which destabilized the passive film and led to the formation of insoluble metal sulfide compounds.

  1. The utilization of the mesoporous Ti-SBA-15 catalyst in the epoxidation of allyl alcohol to glycidol and diglycidyl ether in the water medium

    Directory of Open Access Journals (Sweden)

    Wróblewska Agnieszka

    2015-12-01

    Full Text Available This work presents the studies on the optimization the process of allyl alcohol epoxidation over the Ti-SBA-15 catalyst. The optimization was carried out in an aqueous medium, wherein water was introduced into the reaction medium with an oxidizing agent (30 wt% aqueous solution of hydrogen peroxide and it was formed in the reaction medium during the processes. The main investigated technological parameters were: the temperature, the molar ratio of allyl alcohol/hydrogen peroxide, the catalyst content and the reaction time. The main functions the process were: the selectivity of transformation to glycidol in relation to allyl alcohol consumed, the selectivity of transformation to diglycidyl ether in relation to allyl alcohol consumed, the conversion of allyl alcohol and the selectivity of transformation to organic compounds in relation to hydrogen peroxide consumed. The analysis of the layer drawings showed that in water solution it is best to conduct allyl alcohol epoxidation in direction of glycidol (selectivity of glycidol 54 mol% at: the temperature of 10–17°C, the molar ratio of reactants 0.5–1.9, the catalyst content 2.9–4.0 wt%, the reaction time 2.7–3.0 h and in direction of diglycidyl ether (selectivity of diglycidyl ether 16 mol% at: the temperature of 18–33°C, the molar ratio of reactants 0.9–1.65, the catalyst content 2.0–3.4 wt%, the reaction time 1.7–2.6 h. The presented method allows to obtain two very valuable intermediates for the organic industry.

  2. Os and S isotope studies of ultramafic rocks in the Duke Island Complex, Alaska: variable degrees of crustal contamination of magmas in an arc setting and implications for Ni-Cu-PGE sulfide mineralization

    Science.gov (United States)

    Stifter, Eric C.; Ripley, Edward M.; Li, Chusi

    2016-03-01

    The Duke Island Complex is one of the several "Ural-Alaskan" intrusions of Cretaceous age that occur along the coast of SE Alaska. Significant quantities of magmatic Ni-Cu-PGE sulfide mineralization are locally found in the complex, primarily within olivine clinopyroxenites. Sulfide mineralization is Ni-poor, consistent with petrologic evidence which indicates that sulfide saturation was reached after extensive olivine crystallization. Olivine clinopyroxenites were intruded by magmas that produced sulfide-poor, adcumulate dunites. As part of a study to investigate the potential for Ni-rich sulfide mineralization in association with the dunites, a Re-Os and S isotope study of the dunites, as well as sulfide mineralization in the olivine clinopyroxenites, was initiated. Importantly, recent drilling in the complex identified the presence of sulfidic and carbonaceous country rocks that may have been involved in the contamination of magmas and generation of sulfide mineralization. γOs (110 Ma) values of two sulfidic country rocks are 1022 and 2011. δ34S values of the country rocks range from -2.6 to -16.1 ‰. 187Os/188Os ratios of sulfide minerals in the mineralization hosted by olivine clinopyroxenites are variable and high, with γOs (110 Ma) values between 151 and 2059. Extensive interaction with Re-rich sedimentary country rocks is indicated. In contrast, γOs (110 Ma) values of the dunites are significantly lower, ranging between 2 and 16. 187Os/188Os ratios increase with decreasing Os concentration. This inverse relation is similar to that shown by ultramafic rocks from several arc settings, as well as altered abyssal dunites and peridotites. The relation may be indicative of magma derivation from a sub-arc mantle that had experienced metasomatism via slab-derived fluids. Alternatively, the relation may be indicative of minor contamination of magma by crustal rocks with low Os concentrations but high 187Os/188Os ratios. A third alternative is that the low Os

  3. Preparation and reactivity of metal-containing monomers. Communication 2. Radiation graft polymerization of allyl alcohol complexed on polyethylene

    International Nuclear Information System (INIS)

    A study of the postradiation graft polymerization of complexed allyl alcohol was carried out for the first time. Copolymers were obtained containing up to 2.4 mass % polyallyl alcohol and 2.4 mass % metal. The grafting rate is constant for several hours and increases with an increase in the concentration of the complexing agent in the reaction mixture up to [CoCl2]:[AA] mole ratio equal to 1:5

  4. Air-water transfer of hydrogen sulfide

    DEFF Research Database (Denmark)

    Yongsiri, C.; Vollertsen, J.; Rasmussen, M. R.;

    2004-01-01

    The emissions process of hydrogen sulfide was studied to quantify air–water transfer of hydrogen sulfide in sewer networks. Hydrogen sulfide transfer across the air–water interface was investigated at different turbulence levels (expressed in terms of the Froude number) and pH using batch...... experiments. By means of the overall mass–transfer coefficient (KLa), the transfer coefficient of hydrogen sulfide (KLaH2S), referring to total sulfide, was correlated to that of oxygen (KLaO2) (i.e., the reaeration coefficient). Results demonstrate that both turbulence and pH in the water phase play...... a significant role for KLaH2S. An exponential expression is a suitable representation for the relationship between KLaH2S and the Froude number at all pH values studied (4.5 to 8.0). Because of the dissociation of hydrogen sulfide, KLaH2S increased with decreasing pH at a constant turbulence level. Relative...

  5. Enantioconvergent synthesis by sequential asymmetric Horner-Wadsworth-Emmons and palladium-catalyzed allylic substitution reactions

    DEFF Research Database (Denmark)

    Pedersen, Torben Møller; Hansen, E. Louise; Kane, John;

    2001-01-01

    A new method for enantioconvergent synthesis has been developed. The strategy relies on the combination of an asymmetric Horner-Wadsworth-Emmons (HWE) reaction and a palladium-catalyzed allylic substitution. Different $alpha@-oxygen-substituted, racemic aldehydes were initially transformed by...... asymmetric HWE reactions into mixtures of two major $alpha@,$beta@-unsaturated esters, possessing opposite configurations at their allylic stereocenters as well as opposite alkene geometry. Subsequently, these isomeric mixtures of alkenes could be subjected to palladium-catalyzed allylic substitution...

  6. Regiochemical Control in the Metal-Catalyzed Transposition of Allylic Silyl Ethers

    OpenAIRE

    Hansen, Eric C.; Lee, Daesung

    2006-01-01

    A novel mode of regiochemical control over the allylic [1,3]-transposition of silyloxy groups catalyzed by Re2O7 has been developed. This strategy relies on a cis-oriented vinyl boronate, generated from the Alder ene reaction of homoallylic silyl ethers and alkynyl boronates, to trap out the allylic hydroxyl group. The resulting cyclic boronic acids are excellent partners for cross coupling reactions. High chirality transfer is observed for the rearrangement of enantioenriched allylic silyl e...

  7. Extraction of Nanosized Cobalt Sulfide from Spent Hydrocracking Catalyst

    OpenAIRE

    Samia A. Kosa; Hegazy, Eman Z.

    2013-01-01

    The processes used for the extraction of metals (Co, Mo, and Al) from spent hydrotreating catalysts were investigated in this study. A detailed mechanism of the metal extraction process is described. Additionally, a simulation study was performed to understand the sulfidizing mechanism. The suggested separation procedure was effective and achieved an extraction of approximately 80–90%. In addition, the sulfidization mechanism was identified. This sulfidizing process for Co was found to involv...

  8. The pure rotational spectrum of a Claisen rearrangement precursor Allyl Phenyl Ether using CP-FTMW spectroscopy

    Science.gov (United States)

    Grubbs, G. S.; Frank, Derek S.; Obenchain, Daniel A.; Cooke, S. A.; Novick, Stewart E.

    2016-06-01

    The pure rotational spectrum of a Claisen rearrangement precursor, Allyl Phenyl Ether (APE), has been measured on a chirped pulse Fourier transform microwave (CP-FTMW) spectrometer in the 8-14 GHz region. Rotational and centrifugal distortion constants for multiple conformations have been determined and are reported for the first time. This is the first study of a phenyl-containing ether where multiple conformers were experimentally observed all within their ground vibrational states. Quantum chemical calculations have been performed to isolate low energy geometries of APE and are implemented to aid in spectral assignment. Other structural parameters such as planar moments and inertial defects for the Allyl Phenyl Ether conformers are presented and compared to similar molecules.

  9. Allyl thiourea as a corrosion inhibitor for cold rolled steel in H3PO4 solution

    International Nuclear Information System (INIS)

    Highlights: ► Allyl thiourea (ATU) acts as a good inhibitor for steel in 1.0 M H3PO4. ► Inhibition efficiency increases slightly with the temperature at 0.2–0.5 mM. ► The adsorption of ATU on steel surface obeys Langmuir adsorption isotherm. ► ATU behaves as a mixed-type inhibitor. - Abstract: The inhibition effect of allyl thiourea (ATU) on the corrosion of cold rolled steel (CRS) in 1.0 M H3PO4 solution at 20–50 °C was studied by weight loss, potentiodynamic polarisation, electrochemical impedance spectroscopy (EIS) and scanning electron microscopy (SEM) methods. The results show that ATU is a good inhibitor, and the maximum inhibition efficiency of 0.5 mM inhibitor is higher than 95% at all studied temperatures. The adsorption of ATU obeys Langmuir adsorption isotherm. Polarisation curves show that ATU behaves as a mixed-type inhibitor. EIS spectra exhibit one capacitive loop. The inhibition action is also evidenced by SEM.

  10. Comparative geochemical study of soils developed on characteristic black and yellow polymetallic massive sulfide deposits in Eastern Pontides (NE Turkey)

    OpenAIRE

    KÖPRÜBAŞI, Nezihi; ÇİFTÇİ, Emin; CORDAN, Sait; KÖPRÜBAŞI, Necla; ÖZKUL, Cafer; TÜKEL, Fatma ŞİŞMAN

    2014-01-01

    The Harşit-Köprübaşı (Tirebolu) and Killik (Espiye) volcanogenic massive sulfide (VMS) deposits occur in the Eastern Pontide tectonic belt, one of the major tectonic units comprising Anatolia. They are hosted by Late Cretaceous dacitic to rhyolitic rocks overlain by thin layers of pelitic sediments. The region is considered as a metallogenic province since it is a host to numerous VMS deposits, mainly of the Kuroko type, with varying sizes and reserves and with fairly similar geochemical and ...

  11. Iron complexes of tetramine ligands catalyse allylic hydroxyamination via a nitroso–ene mechanism

    Science.gov (United States)

    Porter, David; Poon, Belinda M-L

    2015-01-01

    Summary Iron(II) complexes of the tetradentate amines tris(2-pyridylmethyl)amine (TPA) and N,N′-bis(2-pyridylmethyl)-N,N′-dimethylethane-1,2-diamine (BPMEN) are established catalysts of C–O bond formation, oxidising hydrocarbon substrates via hydroxylation, epoxidation and dihydroxylation pathways. Herein we report the capacity of these catalysts to promote C–N bond formation, via allylic amination of alkenes. The combination of N-Boc-hydroxylamine with either FeTPA (1 mol %) or FeBPMEN (10 mol %) converts cyclohexene to the allylic hydroxylamine (tert-butyl cyclohex-2-en-1-yl(hydroxy)carbamate) in moderate yields. Spectroscopic studies and trapping experiments suggest the reaction proceeds via a nitroso–ene mechanism, with involvement of a free N-Boc-nitroso intermediate. Asymmetric induction is not observed using the chiral tetramine ligand (+)-(2R,2′R)-1,1′-bis(2-pyridylmethyl)-2,2′-bipyrrolidine ((R,R′)-PDP). PMID:26734101

  12. Iron complexes of tetramine ligands catalyse allylic hydroxyamination via a nitroso–ene mechanism

    Directory of Open Access Journals (Sweden)

    David Porter

    2015-12-01

    Full Text Available Iron(II complexes of the tetradentate amines tris(2-pyridylmethylamine (TPA and N,N′-bis(2-pyridylmethyl-N,N′-dimethylethane-1,2-diamine (BPMEN are established catalysts of C–O bond formation, oxidising hydrocarbon substrates via hydroxylation, epoxidation and dihydroxylation pathways. Herein we report the capacity of these catalysts to promote C–N bond formation, via allylic amination of alkenes. The combination of N-Boc-hydroxylamine with either FeTPA (1 mol % or FeBPMEN (10 mol % converts cyclohexene to the allylic hydroxylamine (tert-butyl cyclohex-2-en-1-yl(hydroxycarbamate in moderate yields. Spectroscopic studies and trapping experiments suggest the reaction proceeds via a nitroso–ene mechanism, with involvement of a free N-Boc-nitroso intermediate. Asymmetric induction is not observed using the chiral tetramine ligand (+-(2R,2′R-1,1′-bis(2-pyridylmethyl-2,2′-bipyrrolidine ((R,R′-PDP.

  13. Microaeration for hydrogen sulfide removal in UASB reactor.

    Science.gov (United States)

    Krayzelova, Lucie; Bartacek, Jan; Kolesarova, Nina; Jenicek, Pavel

    2014-11-01

    The removal of hydrogen sulfide from biogas by microaeration was studied in Up-flow Anaerobic Sludge Blanket (UASB) reactors treating synthetic brewery wastewater. A fully anaerobic UASB reactor served as a control while air was dosed into a microaerobic UASB reactor (UMSB). After a year of operation, sulfur balance was described in both reactors. In UASB, sulfur was mainly presented in the effluent as sulfide (49%) and in biogas as hydrogen sulfide (34%). In UMSB, 74% of sulfur was detected in the effluent (41% being sulfide and 33% being elemental sulfur), 10% accumulated in headspace as elemental sulfur and 9% escaped in biogas as hydrogen sulfide. The efficiency of hydrogen sulfide removal in UMSB was on average 73%. Microaeration did not cause any decrease in COD removal or methanogenic activity in UMSB and the elemental sulfur produced by microaeration did not accumulate in granular sludge. PMID:25270045

  14. Synchrotron Photoionization Mass Spectrometry Measurements of Kinetics and Product Formation in the Allyl Radical (H2CCHCH2)Self Reaction

    Science.gov (United States)

    Selby, Talitha M.; Melini, giovanni; Goulay, Fabien; Leone, Stephen R.; Fahr, Askar; Taatjes, Craig A.; Osborn, David L.

    2008-01-01

    Product channels for the self-reaction of the resonance-stabilized allyl radical, C3H5 + C3H5, have been studied with isomeric specificity at temperatures from 300-600 K and pressures from 1-6 Torr using time-resolved multiplexed photoionization mass spectrometry. Under these conditions 1,5-hexadiene was the only C6H10 product isomer detected. The lack of isomerization of the C6H10 product is in marked contrast to the C6H6 product in the related C3H3 + C3H3 reaction, and is due to the more saturated electronic structure of the C6H10 system. The disproportionation product channel, yielding allene + propene, was also detected, with an upper limit on the branching fraction relative to recombination of 0.03. Analysis of the allyl radical decay at 298 K yielded a total rate coefficient of (2.7 +/- 0.8) x 10(exp -11) cu cm/molecule/s, in good agreement with pre.vious experimental measurements using ultraviolet kinetic absorption spectroscopy and a recent theoretical determination using variable reaction coordinate transition state theory. This result provides independent indirect support for the literature value of the allyl radical ultraviolet absorption cross-section near 223 nm.

  15. Exciton Coupling in Circular Dichroic Spectroscopy as a Tool for Establishing the Absolute Configuration of alpha,beta-Unsaturated Esters of Allylic Alcohols

    DEFF Research Database (Denmark)

    Lauridsen, A.; Cornett, Claus; Christensen, S. B.

    1991-01-01

    alpha-beta-Unsaturated esters of allylic alcohols have been shown to exhibit exciton coupling by circular dichroic spectroscopy. This coupling permits the establishment of the absolute configuration. The method was used to prove the absolute configuration at C-2 of archangelolide. Detailed NMR sp...... spectral studies of the prepared model structures may be used as a reference for stereoisomeric guaianolides....

  16. Carbon steel protection in G.S. (Girlder sulfide) plants. Iron sulfide scales formation conditions. Pt. 1

    International Nuclear Information System (INIS)

    An ASTM A 516 degree 60 carbon steel superficial protection technique submitted to a hydrogen-water sulfide corrosive medium at 2 MPa of pressure and 40-125 deg C forming on itself an iron sulfide layer was tested. Studies on pH influence, temperature, passivating mean characteristics and exposure time as well as the mechanical resistance of sulfide layers to erosion are included. (Author)

  17. Investigation into leaching of indium-containing sulfide cake

    International Nuclear Information System (INIS)

    Data are given of laboratory investigations into indium leaching from commercial-grade sulfide cake. Two indium extraction methods are studied: exchange sulfide decomposition by blue vitriol treatment, sulfide destruction by means of an oxidizer where manganese ore containing manganese dioxide and zinc cake containing zinc ferrite have been used. The influence of the reagent consumption temperature, duration of leaching on the indium extraction is estimated as well as into on the Copper and arsenic transport into the solution. Optimal conditions for the indium extraction from sulfide cake under salt leaching and oxidizing treatment are established

  18. Limitation of Sulfide Capacity Concept for Molten Slags

    Science.gov (United States)

    Jung, In-Ho; Moosavi-Khoonsari, Elmira

    2016-04-01

    The sulfide capacity concept has been widely used in pyrometallurgy to define sulfur removal capacities of slags. Typically, the sulfide capacity is considered to be a unique slag property depending only on temperature regardless of partial pressures of oxygen and sulfur. In the present study, it is demonstrated that sulfide capacities of slags in particular those of Na2O-containing slags can vary with partial pressures of oxygen and sulfur due to large solubility of sulfide in Na2O-containing slag systems.

  19. Activity studies of sesquiterpene oxides and sulfides from the plant Hyptis suaveolens (Lamiaceae) and its repellency on Ixodes ricinus (Acari: Ixodidae).

    Science.gov (United States)

    Ashitani, T; Garboui, S S; Schubert, F; Vongsombath, C; Liblikas, I; Pålsson, K; Borg-Karlson, A-K

    2015-12-01

    Hyptis suaveolens (Lamiaceae), a plant traditionally used as a mosquito repellent, has been investigated for repellent properties against nymphs of the tick Ixodes ricinus. Essential oils and volatile compounds of fresh and dried leaves, from plants originating from Laos and Guinea-Bissau, were identified by GC-MS and tested in a tick repellency bioassay. All the essential oils were strongly repellent against the ticks, even though the main volatile constituents differed in their proportions of potentially tick repellent chemicals. (+)/(-)-sabinene were present in high amounts in all preparations, and dominated the emission from dry and fresh leaves together with 1,8-cineol and α-phellandrene. 1,8-Cineol and sabinene were major compounds in the essential oils from H. suaveolens from Laos. Main compounds in H. suaveolens from Guinea-Bissau were (-)-sabinene, limonene and terpinolene. Among the sesquiterpene hydrocarbons identified, α-humulene exhibited strong tick repellency (96.8 %). Structure activity studies of oxidation or sulfidation products of germacrene D, α-humulene and β-caryophyllene, showed increased tick repellent activity: of mint sulfide (59.4 %), humulene-6,7-oxide (94.5 %) and caryophyllene-6,7-oxide (96.9 %). The substitution of oxygen with sulfur slightly lowered the repellency. The effects of the constituents in the oils can then be regarded as a trade off between the subsequently lower volatility of the sesquiterpene derivatives compared to the monoterpenes and may thus increase their potential usefulness as tick repellents. PMID:26385208

  20. SULFIDE METHOD PLUTONIUM SEPARATION

    Science.gov (United States)

    Duffield, R.B.

    1958-08-12

    A process is described for the recovery of plutonium from neutron irradiated uranium solutions. Such a solution is first treated with a soluble sullide, causing precipitation of the plutoniunn and uraniunn values present, along with those impurities which form insoluble sulfides. The precipitate is then treated with a solution of carbonate ions, which will dissolve the uranium and plutonium present while the fission product sulfides remain unaffected. After separation from the residue, this solution may then be treated by any of the usual methods, such as formation of a lanthanum fluoride precipitate, to effect separation of plutoniunn from uranium.

  1. Catalyst-controlled switch of regioselectivity in the asymmetric allylic alkylation of oxazolones with MBHCs.

    Science.gov (United States)

    Zhu, Gongming; Yang, Junxian; Bao, Guangjun; Zhang, Ming; Li, Jing; Li, Yiping; Sun, Wangsheng; Hong, Liang; Wang, Rui

    2016-06-14

    A catalyst-controlled switch of regioselectivity in asymmetric allylic alkylation of oxazolones with MBHCs was described. The SN2'-SN2' reaction catalysed by a quinine-derived base produced γ-selective secondary allylic oxazolone derivatives, whereas the addition-elimination reaction catalysed by an amino acid-derived bifunctional urea catalyst provided β-selective primary adducts. PMID:27250517

  2. Memory effects in palladium-catalyzed allylic Alkylations of 2-cyclohexen-1-yl acetate

    DEFF Research Database (Denmark)

    Svensen, Nina; Fristrup, Peter; Tanner, David Ackland;

    2007-01-01

    The objective of this work was to characterize the enantiospecificity of the allylic alkylation of enantioenriched 2-cyclohexen-1-yl acetate with the enolate ion of dimethyl malonate catalyzed by unsymmetrical palladium catalysts. The precatalysts employed were (eta(3)-allyl)PdLCl, where L is a...

  3. Magnetic silica supported palladium catalyst: synthesis of allyl aryl ethers in water

    Science.gov (United States)

    A simple and benign procedure for the synthesis of aryl allyl ethers has been developed using phenols, allyl acetates and magnetically recyclable silica supported palladium catalyst in water; performance of reaction in air and easy separation of the catalyst using an external mag...

  4. Palladium(0)-Catalyzed Intermolecular Allylic Dearomatization of Indoles by a Formal [4+2] Cycloaddition Reaction.

    Science.gov (United States)

    Gao, Run-Duo; Xu, Qing-Long; Zhang, Bo; Gu, Yiting; Dai, Li-Xin; You, Shu-Li

    2016-08-01

    Bridged indoline derivatives were synthesized by an intermolecular Pd-catalyzed allylic dearomatization reaction of substituted indoles. The reaction between indoles and allyl carbonates bearing a nucleophilic alcohol side-chain proceeds in a cascade fashion, providing bridged indolines in excellent enantioselectivity. PMID:27321285

  5. Trifluoromethylallylation of Heterocyclic C-H Bonds with Allylic Carbonates under Rhodium Catalysis.

    Science.gov (United States)

    Choi, Miji; Park, Jihye; Sharma, Satyasheel; Jo, Hyeim; Han, Sangil; Jeon, Mijin; Mishra, Neeraj Kumar; Han, Sang Hoon; Lee, Jong Suk; Kim, In Su

    2016-06-01

    The rhodium(III)-catalyzed γ-trifluoromethylallylation of various heterocyclic C-H bonds with CF3-substituted allylic carbonates is described. These reactions provide direct access to linear CF3-containing allyl frameworks with complete trans-selectivity via C-H bond activation followed by a formal SN-type reaction pathway. PMID:27187625

  6. Z-Selective copper-catalyzed asymmetric allylic alkylation with Grignard reagents.

    Science.gov (United States)

    Giannerini, Massimo; Fañanás-Mastral, Martín; Feringa, Ben L

    2012-03-01

    Allylic gem-dichlorides undergo regio- and enanantioselective (er up to 99:1) copper-catalyzed allylic alkylation with Grignard reagents affording chiral Z-vinyl chlorides. This highly versatile class of synthons can be subjected to Suzuki cross coupling affording optically active Z-alkenes and 1,3-cis,trans dienes. PMID:22352853

  7. Z-Selective Copper-Catalyzed Asymmetric Allylic Alkylation with Grignard Reagents

    OpenAIRE

    Giannerini, Massimo; Fananas-Mastral, Martin; Feringa, Ben L.; Fañanás-Mastral, Martín

    2012-01-01

    Allylic gem-dichlorides undergo regio- and enanantioselective (er up to 99:1) copper-catalyzed allylic alkylation with Grignard reagents affording chiral Z-vinyl chlorides. This highly versatile class of synthons can be subjected to Suzuki cross coupling affording optically active Z-alkenes and 1,3-cis,trans dienes.

  8. Green Synthesis and Regioselective Control of Sn/I2 Mediated Allylation of Carbonyl Compounds with Crotyl Halide in Water

    Institute of Scientific and Technical Information of China (English)

    ZHANG,Yan; ZHA,Zhang-Gen; ZHOU,Yu-Qing; WANG,Zhi-Yong

    2004-01-01

    @@ Barbier-type carbonyl allylation is particularly useful due to ease of operation and the availability and tractability of allylic substrates,[1] Metals such as indium, zinc and tin are often used as the mediator. Here we present a green approach toward the synthesis, that is, Sn/I2 mediated allylation of carbonyl compounds with crotyl halide in water.

  9. Titanocene sulfide chemistry

    Czech Academy of Sciences Publication Activity Database

    Horáček, Michal

    2016-01-01

    Roč. 314, MAY 2016 (2016), s. 83-102. ISSN 0010-8545 R&D Projects: GA ČR(CZ) GAP207/12/2368 Institutional support: RVO:61388955 Keywords : titanocene sulfide chemistry * photolysis * titanocene hydrosulfides Ti-(SH)n Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 12.239, year: 2014

  10. Construction of an Asymmetric Quaternary Carbon Center via Allylation of Hydrazones

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jin Bum; Satyender, Apuri; Jang, Doo Ok [Yonsei Univ., Wonju (Korea, Republic of)

    2013-11-15

    Asymmetric indium-mediated allylation of imine derivatives bearing a chiral auxiliary is a reliable strategy for the synthesis of chiral homoallylic amines. Various techniques for indium-mediated stereoselective allylation of imines bearing a chiral auxiliary have been reported. In 1997 Loh and co-workers reported indium-mediated allylation with imines derived from L-valine methyl ester. Since then, many forms of indium-mediated allylation bearing a chiral auxiliary have been reported, including imines derived from (S)-valinol, (R)-phenylglycinol, uracil, (R)-phenylglycinol methyl ester, N-tert-butanesufinamide, and (1R,2S)-1-amino-2-indanol. However, the synthesis of chiral auxiliaries often involves a laborious multi-step synthesis with expensive reagents. Therefore, the development of readily accessible chiral auxiliaries for asymmetric indium-mediated all-ylation is in high demand.

  11. 烯丙基酚醛树脂的固化动力学%Curing Kinetics of Allyl Phenolic Resin

    Institute of Scientific and Technical Information of China (English)

    刘洋; 刘诗薇; 李志强; 于景坤

    2012-01-01

    The curing behavior of allyl phenolic resin was analyzed at different heating rates using differential scanning calorimetry.The obtained kinetic data were treated by Kissinger and KAS(Kissinger-Akahira-Sunose) methods to obtain the curing reaction kinetic parameters.A curing kinetics model was established for allyl phenolic resin.Compared with phenolic resin,the curing temperature of allyl phenolic resin is higher,the reaction order is closer to 1,and the average activation energy of the curing reaction is lower,111.45 kJ/mol.The activation energy of allyl phenolic resin is almost constant and changes little with temperature in the curing process.The curing kinetics model of allyl phenolic resin provides a theoretical basis for the study of curing process parameters.%利用差示扫描量热法分析了烯丙基酚醛树脂在不同升温速率下的固化行为,用Kissinger法和KAS(Kissinger-Akahira-Sunose)法对获得的动力学数据进行处理,得到了固化反应动力学参数,并建立了烯丙基酚醛树脂的固化动力学模型.结果表明:与纯酚醛树脂相比,烯丙基酚醛树脂固化温度较高,反应级数更接近于1,固化反应所需的平均表观活化能较低,为111.45kJ/mol;在整个固化过程中,烯丙基酚醛树脂的活化能较为恒定,随温度变化不大;烯丙基酚醛树脂固化动力学模型为研究该体系固化工艺参数提供了理论依据.

  12. Cutting thin sheets of allyl diglycol carbonate (CR-39) with a CW CO2, laser

    International Nuclear Information System (INIS)

    Recent studies have shown that Allyl Diglycol Carbonate, commercially known as CR-39 (the most sensitive among etch track detectors) can detect relativistic oxygen and other heavier nuclei. We are using large sheets of special grade CR-39 (DOP) in our experiment in Space Shuttle-Spacelab-3. As CR-39 is a highly brittle substance, special care is required to cut CR-39 shetts, especially in case of large sheets and circular cuts. A study of cutting of CR-39 sheets using laser light is described in this paper. It has been found that this method is sufficiently fast to handle large number of sheets and also equally safe for big sheets. A maximum speed up to 200 cm/min with a 5 x 104 W/cm2 laser is obtained during the present study. This study also shows that laser cutting does not affect the track properties of CR-39. (orig.)

  13. Phase Engineering of 2D Tin Sulfides.

    Science.gov (United States)

    Mutlu, Zafer; Wu, Ryan J; Wickramaratne, Darshana; Shahrezaei, Sina; Liu, Chueh; Temiz, Selcuk; Patalano, Andrew; Ozkan, Mihrimah; Lake, Roger K; Mkhoyan, K A; Ozkan, Cengiz S

    2016-06-01

    Tin sulfides can exist in a variety of phases and polytypes due to the different oxidation states of Sn. A subset of these phases and polytypes take the form of layered 2D structures that give rise to a wide host of electronic and optical properties. Hence, achieving control over the phase, polytype, and thickness of tin sulfides is necessary to utilize this wide range of properties exhibited by the compound. This study reports on phase-selective growth of both hexagonal tin (IV) sulfide SnS2 and orthorhombic tin (II) sulfide SnS crystals with diameters of over tens of microns on SiO2 substrates through atmospheric pressure vapor-phase method in a conventional horizontal quartz tube furnace with SnO2 and S powders as the source materials. Detailed characterization of each phase of tin sulfide crystals is performed using various microscopy and spectroscopy methods, and the results are corroborated by ab initio density functional theory calculations. PMID:27099950

  14. Thermodynamics of Complex Sulfide Inclusion Formation in Ca-Treated Al-Killed Structural Steel

    Science.gov (United States)

    Guo, Yin-tao; He, Sheng-ping; Chen, Gu-jun; Wang, Qian

    2016-05-01

    Controlling the morphology of the sulfide inclusion is of vital importance in enhancing the properties of structural steel. Long strip-shaped sulfides in hot-rolled steel can spherize when, instead of the inclusion of pure single-phase MnS, the guest is a complex sulfide, such as an oxide-sulfide duplex and a solid-solution sulfide particle. In this study, the inclusions in a commercial rolled structural steel were investigated. Spherical and elongated oxide-sulfide duplex as well as single-phase (Mn,Ca)S solid solution inclusions were observed in the steel. A thermodynamic equilibrium between the oxide and sulfide inclusions was proposed to understand the oxide-sulfide duplex inclusion formation. Based on the equilibrium solidification principle, thermodynamic discussions on inclusion precipitation during the solidification process were performed for both general and resulfurized structural steel. The predicted results of the present study agreed well with the experimental ones.

  15. Studies of high temperature ternary phases in mixed-metal-rich early transition metal sulfide and phosphide systems

    Energy Technology Data Exchange (ETDEWEB)

    Marking, G.A.

    1994-01-04

    Investigations of ternary mixed early transition metal-rich sulfide and phosphide systems resulted in the discovery of new structures and new phases. A new series of Zr and Hf - group V transition metal - sulfur K-phases was synthesized and crystallographically characterized. When the group V transition metal was Nb or Ta, the unit cell volume was larger than any previously reported K-phase. The presence of adventitious oxygen was determined in two K-phases through a combination of neutron scattering and X-ray diffraction experiments. A compound Hf{sub 10}Ta{sub 3}S{sub 3} was found to crystallize in a new-structure type similar to the known gamma brasses. This structure is unique in that it is the only reported {open_quotes}stuffed{close_quotes} gamma-brass type structure. The metal components, Hf and Ta, are larger in size and more electropositive than the metals found in normal gamma brasses (e.g. Cu and Zn) and because of the larger metallic radii, sulfur can be incorporated into the structure where it plays an integral role in stabilizing this phase relative to others. X-ray single-crystal, X-ray powder and neutron powder refinements were performed on this structure. A new structure was found in the ternary Nb-Zr-P system which has characteristics in common with many known early transition metal-rich sulfides, selenides, and phosphides. This structure has the simplest known interconnection of the basic building blocks known for this structural class. Anomalous scattering was a powerful tool for differentiating between Zr and Nb when using Mo K{alpha} X-radiation. The compounds ZrNbP and HfNbP formed in the space group Prima with the simple Co{sub 2}Si structure which is among the most common structures found for crystalline solid materials. Solid solution compounds in the Ta-Nb-P, Ta-Zr-P, Nb-Zr-P, Hf-Nb-P, and Hf-Zr-S systems were crystallographically characterized. The structural information corroborated ideas about bonding in metal-rich compounds.

  16. Radiation polymerization of allyl derivatives of glycerin

    International Nuclear Information System (INIS)

    Radiation polymerization of 1 allyloxi-3-(chlorine)-alkoxipropanol-2, 1-cro otoxy-3=ethyloxypropanol-2, 1-allylamino-3-amyloxypropanol-2, 1-butoxy-2-allyloxi-3-chlorpropane has been carried out. Some kinetic character ristics of the polymerization process have been obtained. A dependence of the polymerization rate on exposure doze rate, on the persence of modifier (orthopho osphoric acid) and its ratio to the manometer has been studied

  17. Sol-gel processing of metal sulfides

    Science.gov (United States)

    Stanic, Vesha

    Metal sulfides were synthesised via a sol-gel process using various metal alkoxides and hydrogen sulfide in toluene. Colloidal gels were prepared from germanium ethoxide, germanium isopropoxide, zinc tert-butoxide and tungsten (VI) ethoxide, whereas colloidal powder was produced from tungsten (V) dichloride ethoxide. Special precautions were necessary to protect the reaction mixture from water contamination which produced metal oxides. Results indicated that the main source of water is the hydrogen sulfide gas. In addition, synthesis of metal sulfides from a mixture of metal oxide and sulfide was demonstrated by the example of monoclinic germanium disulfide. It was produced by reaction of the sol-gel product with sulfur. Heat treatment of the sol-gel product and sulfur yielded single phase GeSsb2. The sol-gel prepared materials and their heat treated products were characterized by various methods. A chemical kinetics study of the functional groups -OR, -SH and Ssp{2-} was carried out for the sol-gel processing of GeSsb2 from of hydrogen sulfide and two different alkoxides, germanium ethoxide and germanium isopropoxide. The study was performed for different concentrations of precursors at different molar ratios and temperatures. The results indicate that the proposed reaction mechanism was simplified under appropriate reaction conditions. Experimentally determined rate constants of thiolysis and condensations demonstrate that thiolysis is slow and that condensations are fast steps, regardless of the studied reaction conditions. A study of the temperature effect on the reaction rate constant shows that it increases with temperature in accord with both Arrhenius law and transition-state theory. Activation energies, Esba, and activation parameters DeltaSsp{ddagger}, DeltaHsp{ddagger} and DeltaGsp{ddagger}, were determined for thiolysis and condensation reactions. The potentiometric tiration method was used for quantitative determination of germanium sulfide and

  18. Hydrogen sulfide and vascular relaxation

    Institute of Scientific and Technical Information of China (English)

    SUN Yan; TANG Chao-shu; DU Jun-bao; JIN Hong-fang

    2011-01-01

    Objective To review the vasorelaxant effects of hydrogen sulfide (H2S) in arterial rings in the cardiovascular system under both physiological and pathophysiological conditions and the possible mechanisms involved.Data sources The data in this review were obtained from Medline and Pubmed sources from 1997 to 2011 using the search terms "hydrogen sulfide" and ""vascular relaxation".Study selection Articles describing the role of hydrogen sulfide in the regulation of vascular activity and its vasorelaxant effects were selected.Results H2S plays an important role in the regulation of cardiovascular tone.The vasomodulatory effects of H2S depend on factors including concentration,species and tissue type.The H2S donor,sodium hydrosulfide (NarS),causes vasorelaxation of rat isolated aortic rings in a dose-dependent manner.This effect was more pronounced than that observed in pulmonary arterial rings.The expression of KATP channel proteins and mRNA in the aortic rings was increased compared with pulmonary artery rings.H2S is involved in the pathogenesis of a variety of cardiovascular diseases.Downregulation of the endogenous H2S pathway is an important factor in the pathogenesis of cardiovascular diseases.The vasorelaxant effects of H2S have been shown to be mediated by activation of KATP channels in vascular smooth muscle cells and via the induction of acidification due to activation of the CI/HCO3 exchanger.It is speculated that the mechanisms underlying the vasoconstrictive function of H2S in the aortic rings involves decreased NO production and inhibition of cAMP accumulation.Conclusion H2S is an important endogenous gasotransmitter in the cardiovascular system and acts as a modulator of vascular tone in the homeostatic regulation of blood pressure.

  19. Fault locator of an allyl chloride plant

    Directory of Open Access Journals (Sweden)

    Savković-Stevanović Jelenka B.

    2004-01-01

    Full Text Available Process safety analysis, which includes qualitative fault event identification, the relative frequency and event probability functions, as well as consequence analysis, was performed on an allye chloride plant. An event tree for fault diagnosis and cognitive reliability analysis, as well as a troubleshooting system, were developed. Fuzzy inductive reasoning illustrated the advantages compared to crisp inductive reasoning. A qualitative model forecast the future behavior of the system in the case of accident detection and then compared it with the actual measured data. A cognitive model including qualitative and quantitative information by fuzzy logic of the incident scenario was derived as a fault locator for an ally! chloride plant. The obtained results showed the successful application of cognitive dispersion modeling to process safety analysis. A fuzzy inductive reasoner illustrated good performance to discriminate between different types of malfunctions. This fault locator allowed risk analysis and the construction of a fault tolerant system. This study is the first report in the literature showing the cognitive reliability analysis method.

  20. Identifying the Prospective Area of Sulfide Groundwater within the Area of Palvantash Oil and Gas Deposit

    Directory of Open Access Journals (Sweden)

    M. R. Zhurayev

    2014-03-01

    Full Text Available This paper describes the methodology of prospecting for sulfide groundwater in the area of Palvantash oil fields. In result of study allowed determining the favorable conditions for the sulfide waters formation, and mapping the areas of different sulfide water concentration. The relatively permeable areas were established and the water borehole positions were recommended.

  1. Acute inhalation toxicity of carbonyl sulfide

    Energy Technology Data Exchange (ETDEWEB)

    Benson, J.M.; Hahn, F.F.; Barr, E.B. [and others

    1995-12-01

    Carbonyl sulfide (COS), a colorless gas, is a side product of industrial procedures sure as coal hydrogenation and gasification. It is structurally related to and is a metabolite of carbon disulfide. COS is metabolized in the body by carbonic anhydrase to hydrogen sulfide (H{sub 2}S), which is thought to be responsible for COS toxicity. No threshold limit value for COS has been established. Results of these studies indicate COS (with an LC{sub 50} of 590 ppm) is slightly less acutely toxic than H{sub 2}S (LC{sub 50} of 440 ppm).

  2. Ultrafine particles derived from mineral processing: A case study of the Pb-Zn sulfide ore with emphasis on lead-bearing colloids.

    Science.gov (United States)

    Mikhlin, Yuri; Vorobyev, Sergey; Romanchenko, Alexander; Karasev, Sergey; Karacharov, Anton; Zharkov, Sergey

    2016-03-01

    Although mining and mineral processing industry is a vast source of heavy metal pollutants, the formation and behavior of micrometer- and nanometer-sized particles and their aqueous colloids entered the environment from the technological media has received insufficient attention to date. Here, the yield and characteristics of ultrafine mineral entities produced by routine grinding of the Pb-Zn sulfide ore (Gorevskoe ore deposit, Russia) were studied using laser diffraction analysis (LDA), dynamic light scattering (DLS) and zeta potential measurement, microscopy, X-ray photoelectron spectroscopy, with most attention given to toxic lead species. It was revealed, in particular, that the fraction of particles less that 1 μm in the ground ore typical reaches 0.4 vol. %. The aquatic particles in supernatants were micrometer size aggregates with increased content of zinc, sulfur, calcium as compared with the bulk ore concentrations. The hydrodynamic diameter of the colloidal species decreased with time, with their zeta potentials remaining about -12 mV. The colloids produced from galena were composed of 20-50 nm PbS nanoparticles associated with lead sulfate and thiosulfate, while the surface oxidation products at precipitated galena were largely lead oxyhydroxides. The size and zeta potential of the lead-bearing colloids decreased with time down to about 100 nm and from -15 mV to -30 mV, respectively. And, conversely, lead sulfide nanoparticles were mobilized before the aggregates during redispersion of the precipitates in fresh portions of water. The potential environmental impact of the metal-bearing colloids, which is due to the large-scale production and relative stability, is discussed. PMID:26761598

  3. Low-temperature Electrodeposition of Aluminium from Lewis Acidic 1-Allyl-3-methylimidazolium Chloroaluminate Ionic Liquids

    Institute of Scientific and Technical Information of China (English)

    郑勇; 张锁江; 吕兴梅; 王倩; 左勇; 刘恋

    2012-01-01

    Lewis acidic 1-allyl-3-methylimidazolium chloroaluminate ionic liquids were used as promising electrolytes in the low-temperature electrodeposition of aluminium. Systematic studies on deposition process have been performed by cYClic voltammetry and chronoamperometry. The surface morphology and X-ray diffraction (XRD) patterns of deposits prepared at different experimental conditions were also investigated. It was shown that the nucleation density and growth rate of crystallites had a great effect on the structure of aluminium deposited. The crys- tallographic orientation of deposits was mainly influenced by temperature and current density. Smooth, dense and well adherent aluminium coatings were obtained on copper substrates at 10-25 mA.cm^-2 and 313.2-353.2 K. More- over, the current efficiency of deposition and purity of aluminium have been significantly improved, demonstrating that the ionic liquids tested have a prospectful potential in electroplating and electrorefining of aluminium.

  4. Analysis of allyl diglycol carbonate by laser induced-breakdown spectroscopy

    International Nuclear Information System (INIS)

    Laser-induced breakdown spectroscopy (LIBS) has been used to identify the impurities in the allyl diglycol carbonate, which is used as a charged particle track recording material in solid-state nuclear track detectors. Impurities of magnesium, calcium, sodium and silicon are detected. Plasma parameters such as temperature and electron density are also calculated at optimized conditions in air and argon atmosphere using the silicon lines. The temperature of the LIBS plasma produced in argon atmosphere was higher than the temperature of the LIBS plasma produced in air. Variation in the emission intensity of the carbon I line (247.8561 nm) with respect to acquisition delay and laser power is also studied. It is found that the intensities of Ca and Na lines from LIBS spectra were enhanced 30–40 times in an argon atmosphere as compared to air. Hence LIBS in an argon atmosphere can be used for better identification of impurities in plastics. (paper)

  5. Oxidation study of the synthetic sulfides molybdenite (MoS2) and covellite (CuS) by acidithiobacillus ferrooxidants using respirometric experiments

    International Nuclear Information System (INIS)

    This paper analyses the oxidation of covellite and molybdenite by Acidithiobacillus ferrooxidans strain LR using respirometric experiments. The results showed that both sulfides were oxidized by A. ferrooxidans, however, the covellite oxidation was much higher than molybdenite. Regarding the kinetic oxidation, the findings revealed that just molybdenite oxidation followed the classical Michaelis-Menten kinetic. It is probably associated with the pathway which these sulfides react to chemistry-bacterial attack, what is influenced by its electronic structures. Besides, experiments conducted in the presence of Fe3+ did not indicate alterations in molybdenite oxidation. Thus, ferric ions seem not to be essential to the sulfide oxidations. (author)

  6. Effect of Soluble Sulfide on the Activity of Luminescent Bacteria

    Directory of Open Access Journals (Sweden)

    Feng Wang

    2012-05-01

    Full Text Available Sulfide is an important water pollutant widely found in industrial waste water that has attracted much attention. S2−, as a weak acidic anion, is easy hydrolyzed to HS and H2S in aqueous solution. In this study, biological tests were performed to establish the toxicity of sulfide solutions on luminescent bacteria. Considering the sulfide solution was contained three substances—S2−, HS and H2S—the toxicity test was performed at different pH values to investigate which form of sulfide increased light emission and which reduced light emission. It was shown that the EC50 values were close at pH 7.4, 8.0 and 9.0 which were higher than pH 5 and 10. The light emission and sulfide concentrations displayed an inverse exponential dose-response relationship within a certain concentration range at pH 5, 6.5 and 10. The same phenomenon occurred for the high concentration of sulfide at pH 7.4, 8 and 9, in which the concentration of sulfide was HS >> H2S > S2−. An opposite hormesis-effect appeared at the low concentrations of sulfide.

  7. Influence of Water Salinity on Air Purification from Hydrogen Sulfide

    Directory of Open Access Journals (Sweden)

    Leybovych L.I.

    2015-12-01

    Full Text Available Mathematical modeling of «sliding» water drop motion in the air flow was performed in software package FlowVision. The result of mathematical modeling of water motion in a droplet with diameter 100 microns at the «sliding» velocity of 15 m/s is shown. It is established that hydrogen sulfide oxidation occurs at the surface of phases contact. The schematic diagram of the experimental setup for studying air purification from hydrogen sulfide is shown. The results of the experimental research of hydrogen sulfide oxidation by tap and distilled water are presented. The dependence determining the share of hydrogen sulfide oxidized at the surface of phases contact from the dimensionless initial concentration of hydrogen sulfide in the air has been obtained.

  8. A Facile and Mild Synthesis of Trisubstituted Allylic Sulfones from Morita-Baylis-Hillman Carbonates

    Directory of Open Access Journals (Sweden)

    Lin Jiang

    2015-05-01

    Full Text Available An efficient and catalyst-free synthesis of trisubstituted allylic sulfones through an allylic sulfonylation reaction of Morita-Baylis-Hillman (MBH carbonates with sodium sulfinates has been developed. Under the optimized reaction conditions, a series of trisubstituted allylic sulfones were rapidly prepared in good to excellent yields (71%–99% with good to high selectivity (Z/E from 79:21 to >99:1. Compared with known synthetic methods, the current protocol features mild reaction temperature, high efficiency and easily available reagents.

  9. Sulfide oxidation in a biofilter

    DEFF Research Database (Denmark)

    Pedersen, Claus Lunde; Dezhao, Liu; Hansen, Michael Jørgen;

    oxidizing bacteria but several fungal families including Trichocomaceae. A positive correlation was found between the presence of mold and sulfide uptake. However there have been no reports on fungi metabolizing hydrogen sulfide. We hypothesize that the mold increases the air exposed surface, enabling...... higher hydrogen sulfide uptake followed by oxidation catalyzed by iron-containing enzymes such as cytochrome c oxidase in a process uncoupled from energy conservation....

  10. Sulfide oxidation in a biofilter

    DEFF Research Database (Denmark)

    Pedersen, Claus Lunde; Liu, Dezhao; Hansen, Michael Jørgen;

    2012-01-01

    oxidizing bacteria but several fungal families including Trichocomaceae. A positive correlation was found between the presence of mold and sulfide uptake. However there have been no reports on fungi metabolizing hydrogen sulfide. We hypothesize that the mold increases the air exposed surface, enabling...... higher hydrogen sulfide uptake followed by oxidation catalyzed by iron-containing enzymes such as cytochrome c oxidase in a process uncoupled from energy conservation....

  11. Catalytic Reduction of Noble Metal Salts by Sodium Hypophosphite Promoted by the Film Poly-(p-Allyl Ether Benzenesulfonic Acid).

    Science.gov (United States)

    Costa, M I C F; Steter, J R; Purgato, F L S; Romero, J R

    2011-01-01

    Glassy carbon electrodes were coated with the film poly-(p-allyl ether benzenesulfonic acid) by an anodic procedure. Nickel, platinum, and palladium ions were introduced into the film by ion exchange of H(+) with the corresponding salts. These ions were catalytically reduced to their corresponding metals using the known electroless reducing agent sodium hypophosphite. Scanning electron microcopy and energy dispersive X-ray spectroscopy were carried out to demonstrate the occurrence of the catalytic process. To compare this method with another one carried out in our laboratory, the electrocatalytic reduction of H(+) was studied using the same modified electrodes. A suggested mechanism for the catalysis is proposed. PMID:24052832

  12. Asymmetric Catalysis with CO2 : The Direct α-Allylation of Ketones.

    Science.gov (United States)

    Pupo, Gabriele; Properzi, Roberta; List, Benjamin

    2016-05-10

    Quaternary stereocenters are found in numerous bioactive molecules. The Tsuji-Trost reaction has proven to be a powerful C-C bond forming process, and, at least in principle, should be well suited to access quaternary stereocenters via the α-allylation of ketones. However, while indirect approaches are known, the direct, catalytic asymmetric α-allylation of branched ketones has been elusive until today. By combining "enol catalysis" with the use of CO2 as a formal catalyst for asymmetric catalysis, we have now developed a solution to this problem: we report a direct, highly enantioselective and highly atom-economic Tsuji-Trost allylation of branched ketones with allylic alcohol. Our reaction delivers products bearing quaternary stereocenters with high enantioselectivity and water as the sole by-product. We expect our methodology to be of utility in asymmetric catalysis and inspire the design of other highly atom-economic transformations. PMID:27071633

  13. Solid radiation curable polyene compositions containing liquid polythiols and solid styrene-allyl copolymer based polyenes

    International Nuclear Information System (INIS)

    Novel styrene-allyl alcohol copolymer based solid polyene compositions which when mixed with liquid polythiols can form solid curable polyene-polythiol systems are claimed. These solid polyenes, containing at least two reactive carbon-to-carbon unsaturated bonds, are urethane or ester derivatives of styrene-allyl alcohol copolymers. The solid polyenes are prepared by treating the hydroxyl groups of a styrene-allyl alcohol copolymer with a reactive unsaturated isocyanate, e.g., allyl isocyanate or a reactive unsaturated carboxylic acid, e.g., acrylic acid. Upon exposure to a free radical generator, e.g., actinic radiation, the solid polyene-polythiol compositions cure to solid, insoluble, chemically resistant, cross-linked polythioether products. Since the solid polyene-liquid polythiol composition can be cured in a solid state, such a curable system finds particular use in preparation of coatings, imaged surfaces such as photoresists, particularly solder-resistant photoresists, printing plates, etc

  14. Total Synthesis of Clavosolide A via Tandem Allylic Oxidation/Oxa-Conjugate Addition Reaction

    Science.gov (United States)

    Baker, Joseph B.; Kim, Hyoungsu; Hong, Jiyong

    2015-01-01

    The tandem allylic oxidation/oxa-conjugate addition reaction promoted by the gem-disubstituent effect in conjunction with the NHC-mediated oxidative esterification was explored for the facile synthesis of clavosolide A. PMID:26236051

  15. Facile synthesis of allyl resinate monomer in an aqueous solution under microwave irradiation

    Indian Academy of Sciences (India)

    Yanju Lu; Mixia Wang; Zhendong Zhao; Yuxiang Chen; Shichao Xu; Jing Wang; Liangwu Bi

    2015-07-01

    We have developed a facile method for production of allyl resinate monomer (allyl rosin ester) via a phase transfer reaction under microwave irradiation. The synthesis of allyl resinate was conducted using allyl chloride and sodium resinate as starting materials in aqueous solution at 50°C for 30 min with a yield of 94.7%, which is 20% higher than conventional heating method. The products precipitated spontaneously from the aqueous phase after reaction, which significantly facilitated the subsequent separation of monomer products. The synthesized monomer product appeared as a viscous liquid, with a viscosity of 460 mPa·s at 25°C and a density of 1.0469 g/cm3. The physical and chemical properties suggested that the synthesized monomer has great potential for free radical polymerization.

  16. Monitoring sulfide and sulfate-reducing bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Tanner, R.S.

    1995-12-31

    Simple yet precise and accurate methods for monitoring sulfate-reducing bacteria (SRB) and sulfide remain useful for the study of bacterial souring and corrosion. Test kits are available to measure sulfide in field samples. A more precise methylene blue sulfide assay for both field and laboratory studies is described here. Improved media, compared to that in API RP-38, for enumeration of SRB have been formulated. One of these, API-RST, contained cysteine (1.1 mM) as a reducing agent, which may be a confounding source of sulfide. While cysteine was required for rapid enumeration of SRB from environmental samples, the concentration of cysteine in medium could be reduced to 0.4 mM. It was also determined that elevated levels of yeast extract (>1 g/liter) could interfere with enumeration of SRB from environmental samples. The API-RST medium was modified to a RST-11 medium. Other changes in medium composition, in addition to reduction of cysteine, included reduction of the concentration of phosphate from 3.4 mM to 2.2 mM, reduction of the concentration of ferrous iron from 0.8 mM to 0.5 mM and preparation of a stock mineral solution to ease medium preparation. SRB from environmental samples could be enumerated in a week in this medium.

  17. Selective epoxidation of allylic alcohols with a titania-silica aerogel

    Energy Technology Data Exchange (ETDEWEB)

    Dusi, M.; Mallat, T.; Baiker, A. [Lab. of Technical Chemistry, Swiss Federal Inst. of Technology, ETH-Zentrum, Zuerich (Switzerland)

    1998-12-31

    An amorphous mesoporous titania-silica aerogel (20 wt%TiO{sub 2} - 80 wt% SiO{sub 2}) and tert.-butylhydroperoxide (TBHP) have been used for the epoxidation of various allylic alcohols. Allylic alcohols possessing an internal double bond were more reactive than those with a terminal C=C bond. Epoxide selectivities could be improved by addition of (basic) zeolite 4 A and NaHCO{sub 3} to the reaction mixture. (orig.)

  18. Highly selective palladium–benzothiazole carbene-catalyzed allylation of active methylene compounds under neutral conditions

    OpenAIRE

    Antonio Monopoli; Pietro Cotugno; Zambonin, Carlo G.; Francesco Ciminale; Angelo Nacci

    2015-01-01

    The Pd–benzothiazol-2-ylidene complex I was found to be a chemoselective catalyst for the Tsuji–Trost allylation of active methylene compounds carried out under neutral conditions and using carbonates as allylating agents. The proposed protocol consists in a simplified procedure adopting an in situ prepared catalyst from Pd2dba3 and 3-methylbenzothiazolium salt V as precursors. A comparison of the performance of benzothiazole carbene with phosphanes and an analogous imidazolium carbene ligand...

  19. Field method for sulfide determination

    Energy Technology Data Exchange (ETDEWEB)

    Wilson, B L; Schwarser, R R; Chukwuenye, C O

    1982-01-01

    A simple and rapid method was developed for determining the total sulfide concentration in water in the field. Direct measurements were made using a silver/sulfide ion selective electrode in conjunction with a double junction reference electrode connected to an Orion Model 407A/F Specific Ion Meter. The method also made use of a sulfide anti-oxidant buffer (SAOB II) which consists of ascorbic acid, sodium hydroxide, and disodium EDTA. Preweighed sodium sulfide crystals were sealed in air tight plastic volumetric flasks which were used in standardization process in the field. Field standards were prepared by adding SAOB II to the flask containing the sulfide crystals and diluting it to the mark with deionized deaerated water. Serial dilutions of the standards were used to prepare standards of lower concentrations. Concentrations as low as 6 ppB were obtained on lake samples with a reproducibility better than +- 10%.

  20. Sulfide elimination by intermittent nitrate dosing in sewer sediments

    Institute of Scientific and Technical Information of China (English)

    Yanchen Liu; Chen Wu; Xiaohong Zhou; David Z.Zhu; Hanchang Shi

    2015-01-01

    The formation of hydrogen sulfide in biofilms and sediments in sewer systems can cause severe pipe corrosions and health hazards,and requires expensive programs for its prevention.The aim of this study is to propose a new control strategy and the optimal condition for sulfide elimination by intermittent nitrate dosing in sewer sediments.The study was carried out based on lab-scale experiments and batch tests using real sewer sediments.The intermittent nitrate dosing mode and the optimal control condition were investigated.The results indicated that the sulfide-intermittent-elimination strategy by nitrate dosing is advantageous for controlling sulfide accumulation in sewer sediment.The oxidation-reduction potential is a sensitive indicator parameter that can reflect the control effect and the minimum N/S (nitrate/sulfide)ratio with slight excess nitrate is necessary for optimal conditions ofefficient sulfide control with lower carbon source loss.The opth-nal control condition is feasible for the sulfide elimination in sewer systems.

  1. Study on effect of the scavenger for eliminating hydrogen sulfide%硫化氢捕消剂清除硫化氢效果研究

    Institute of Scientific and Technical Information of China (English)

    邹兵; 朱胜杰; 石昕

    2012-01-01

    硫化氢气体是高毒性气体,当其发生泄漏事故时将产生严重危害.目前,应对硫化氢泄漏事故的方法较少,主要为消防水喷淋和人员疏散,不能完全消除硫化氢的危害.针对硫化氢气体的特点,研制了在泄漏事故中用于清除硫化氢气体的捕消剂.硫化氢捕消剂为干粉状的,由吸附载体、反应组分和疏水组分组成.当发生硫化氢泄漏时,将捕消剂喷洒在泄漏源周围的空气中,使捕消剂与硫化氢充分接触反应以降低危害程度和范围.清除硫化氢实验结果表明,硫化氢捕消剂能够有效地清除泄漏在空气中的硫化氢气体.%Hydrogen sulfide is a kind of gas with high toxic, and it will cause serious harm in the event of a leakage. At present, the response to hydrogen sulfide leakage is mainly water spray and personnel evacuation, which can not completely eliminate the hazards of hydrogen sulfide. Hydrogen sulfide scavenger was developed to remove hydrogen sulfide in gas leak. The scavenger was made up of adsorption carrier, reaction components and hydropho-bic friction. When hydrogen sulfide leak, the scavenger will be sprayed into the air. At the same time, the scavenger will react with the hydrogen sulfide in the air to reduce the extent and scope of damage. Experimental results showed that hydrogen sulfide scavenger could effectively eliminate hydrogen sulfide gas in the air.

  2. Primordial Xenon in Allende Sulfides

    Science.gov (United States)

    Lee, J. T.; Manuel, O. K.

    1995-09-01

    The Allende C3V carbonaceous chondrite incorporated isotopically anomalous components of several medium-heavy elements (Z=36-62) from nucleosynthesis [1]. Isotopically distinct Xe (Z=54) has been found in grains ranging from several _ to a few mm in size. Diamond [2] is the host of Xe that is enriched in isotopes produced by the very rapid p- and r-processes in a supernova explosion [3]. Silicon carbide [4] is the host of Xe that is enriched in the middle isotopes, 128-132Xe, produced by slow neutron capture [3] before a star reaches the supernova stage. The present study was undertaken to identify the isotopic composition of primitive Xe initially trapped in sulfides of the Allende meteorite. Two FeS mineral separates were analyzed by stepwise heating. One sample was first irradiated in a neutron flux to generate a tracer isotope, 131*Xe, by the 130Te(n, gamma beta-)131*Xe reaction. The release pattern of this tracer isotope, 131*Xe, closely paralleled the release of primordial 132Xe up to 950 degrees C, when the sulfide melted and released the bulk of its trapped Xe (Figure 1). The Xe released from both samples at 950 deg C was terrestrial in isotopic composition, except for enrichments from spallogenic and radiogenic components (Figure 2). From the results of this and earlier analyses of Xe in meteoritic FeS [5, 6, 7], we conclude that terrestrial-type Xe was dominant in the central region of the protoplanetary nebula, and it remains a major component in the FeS of diverse meteorites and in the terrestrial planets that are rich in Fe, S [8]. References: [1] Begemann F. (1993) Origin and Evolution of the Elements (N. Prantzos et al., eds.), 518-527, Cambridge Univ. [2] Lewis R. S. and Anders E. (1988) LPS XIX, 679-680. [3] Burbidge et al. (1957) Rev. Modern Phys., 29, 547-650. [4] Tang M. and Anders E. (1988) GCA, 52, 1235-1244. [5] Niemeyer S. (1979) GCA, 43, 843-860. [6] Lewis et al. (1979) GCA, 43, 1743-1752. [7] Hwaung G. and Manuel O. K. (1982) Nature, 299

  3. γ‐ and δ-Lactams through Palladium-Catalyzed Intramolecular Allylic Alkylation: Enantioselective Synthesis, NMR Investigation, and DFT Rationalization

    DEFF Research Database (Denmark)

    Bantreil, Xavier; Prestat, Guillaume; Moreno, Aitor;

    2011-01-01

    The Pd-catalyzed intramolecular allylic alkylation of unsaturated amides to give gamma- and delta-lactams has been studied in the presence of chiral ligands. Ligand (R)-3,5-tBu-MeOBIPHEP (MeOBIPHEP=6,6'-dimethoxybiphenyl-2,2-diyl)bis(diphenylphosphine)) afforded the best results and allowed the c...... reaction pathways. The calculated energy differences were in good agreement with the experimentally observed enantiomeric ratios....

  4. Anti-inflammatory potential of allyl-isothiocyanate – role of Nrf2, NF-κB and microRNA-155

    OpenAIRE

    Wagner, Anika Eva; Boesch-Saadatmandi, Christine; Dose, Janina; Schultheiss, Gerhard; Rimbach, Gerald

    2012-01-01

    Abstract In this study, the underlying mechanisms of the potential anti-inflammatory properties of allyl-isothiocyanate (AITC) were analysed in vitro and in vivo. Murine RAW264.7 macrophages stimulated with lipopolysaccharide (LPS) were supplemented with increasing concentrations of AITC. In addition, C57BL/6 mice (n= 10 per group) were fed a pro-inflammatory high-fat diet and AITC was administered orally via gavage for 7 days. Biomarkers of inflammation were determined both in cultured cells...

  5. Azo dye decolorization assisted by chemical and biogenic sulfide

    Energy Technology Data Exchange (ETDEWEB)

    Prato-Garcia, Dorian [Laboratory for Research on Advanced Processes for Water Treatment, Unidad Académica Juriquilla, Instituto de Ingeniería, Universidad Nacional Autónoma de México, Blvd. Juriquilla 3001, Querétaro 76230 (Mexico); Cervantes, Francisco J. [División de Ciencias Ambientales, Instituto Potosino de Investigación Científica y Tecnológica, Camino a la Presa de San José 2055, San Luis Potosí 78216 (Mexico); Buitrón, Germán, E-mail: gbuitronm@ii.unam.mx [Laboratory for Research on Advanced Processes for Water Treatment, Unidad Académica Juriquilla, Instituto de Ingeniería, Universidad Nacional Autónoma de México, Blvd. Juriquilla 3001, Querétaro 76230 (Mexico)

    2013-04-15

    Highlights: ► Azo dyes were reduced efficiently by chemical and biogenic sulfide. ► Biogenic sulfide was more efficient than chemical sulfide. ► There was no competition between dyes and sulfate for reducing equivalents. ► Aromatic amines barely affected the sulfate-reducing process. -- Abstract: The effectiveness of chemical and biogenic sulfide in decolorizing three sulfonated azo dyes and the robustness of a sulfate-reducing process for simultaneous decolorization and sulfate removal were evaluated. The results demonstrated that decolorization of azo dyes assisted by chemical sulfide and anthraquinone-2,6-disulfonate (AQDS) was effective. In the absence of AQDS, biogenic sulfide was more efficient than chemical sulfide for decolorizing the azo dyes. The performance of sulfate-reducing bacteria in attached-growth sequencing batch reactors suggested the absence of competition between the studied azo dyes and the sulfate-reducing process for the reducing equivalents. Additionally, the presence of chemical reduction by-products had an almost negligible effect on the sulfate removal rate, which was nearly constant (94%) after azo dye injection.

  6. Azo dye decolorization assisted by chemical and biogenic sulfide

    International Nuclear Information System (INIS)

    Highlights: ► Azo dyes were reduced efficiently by chemical and biogenic sulfide. ► Biogenic sulfide was more efficient than chemical sulfide. ► There was no competition between dyes and sulfate for reducing equivalents. ► Aromatic amines barely affected the sulfate-reducing process. -- Abstract: The effectiveness of chemical and biogenic sulfide in decolorizing three sulfonated azo dyes and the robustness of a sulfate-reducing process for simultaneous decolorization and sulfate removal were evaluated. The results demonstrated that decolorization of azo dyes assisted by chemical sulfide and anthraquinone-2,6-disulfonate (AQDS) was effective. In the absence of AQDS, biogenic sulfide was more efficient than chemical sulfide for decolorizing the azo dyes. The performance of sulfate-reducing bacteria in attached-growth sequencing batch reactors suggested the absence of competition between the studied azo dyes and the sulfate-reducing process for the reducing equivalents. Additionally, the presence of chemical reduction by-products had an almost negligible effect on the sulfate removal rate, which was nearly constant (94%) after azo dye injection

  7. The electrochemical behavior of sulfide ions in molten cryolite

    International Nuclear Information System (INIS)

    The electrochemical behavior of sulfide ions in molten cryolite (Na3A1F6) has been studied by cyclic voltammetry using graphite electrodes at 1323 K. The oxidation of sulfide ions is found to proceed via a quasi-reversible mechanism, i.e., one in which the current is controlled by both diffusion and charge transfer kinetics. The transfer coefficient BETA and the standard rate constant k /SUB s/ are estimated to be 0.5 and 0.0042 cm/sec, respectively. The apparent diffusion coefficient for sulfide ions in cryolite at 1323 K is about 3.93 x 10-5 cm2/sec

  8. Effect of Soluble Sulfide on the Activity of Luminescent Bacteria

    OpenAIRE

    Feng Wang; Ling-Ling Wu; Hong-Wen Gao; Ying Shao

    2012-01-01

    Sulfide is an important water pollutant widely found in industrial waste water that has attracted much attention. S2−, as a weak acidic anion, is easy hydrolyzed to HS and H2S in aqueous solution. In this study, biological tests were performed to establish the toxicity of sulfide solutions on luminescent bacteria. Considering the sulfide solution was contained three substances—S2−, HS

  9. Palladium-Catalyzed Dearomative Allylic Alkylation of Indoles with Alkynes To Synthesize Indolenines with C3-Quarternary Centers.

    Science.gov (United States)

    Gao, Shang; Wu, Zijun; Fang, Xinxin; Lin, Aijun; Yao, Hequan

    2016-08-01

    A palladium-catalyzed dearomative allylic alkylation of indoles with alkynes to construct indolenines with C3-quarternary centers was reported. The in situ formed arylallene intermediate omitted the need to install leaving groups on the allylic compounds and employ extra oxidants to oxidize the allylic C-H bonds. The reaction exhibited good functional group tolerance and high atom economy. Moreover, the reaction was further expanded to synthesize pyrroloindolines and furanoindolines. PMID:27442021

  10. Rice: Sulfide-induced Barriers to Root Radial Oxygen Loss, Fe2+ and Water Uptake, and Lateral Root Emergence

    OpenAIRE

    ARMSTRONG, JEAN; Armstrong, William (Canadian painter, civil engineer, photographer, 1822-1914)

    2005-01-01

    • Background and Aims Akagare and Akiochi are diseases of rice associated with sulfide toxicity. This study investigates the possibility that rice reacts to sulfide by producing impermeable barriers in roots.

  11. A Review on Mutagenicity Testing for Hazard Classification of Chemicals at Work: Focusing on in vivo Micronucleus Test for Allyl Chloride.

    Science.gov (United States)

    Rim, Kyung-Taek; Kim, Soo-Jin

    2015-09-01

    Chemical mutagenicity is a major hazard that is important to workers' health. Despite the use of large amounts of allyl chloride, the available mutagenicity data for this chemical remains controversial. To clarify the mutagenicity of allyl chloride and because a micronucleus (MN) test had not yet been conducted, we screened for MN induction by using male ICR mice bone marrow cells. The test results indicated that this chemical is not mutagenic under the test conditions. In this paper, the regulatory test battery and several assay combinations used to determine the genotoxic potential of chemicals in the workplace have been described. Further application of these assays may prove useful in future development strategies of hazard evaluations of industrial chemicals. This study also should help to improve the testing of this chemical by commonly used mutagenicity testing methods and investigations on the underlying mechanisms and could be applicable for workers' health. PMID:26929826

  12. Structure and stability of acrolein and allyl alcohol networks on Ag(111) from density functional theory based calculations with dispersion corrections

    Science.gov (United States)

    Ferullo, Ricardo M.; Branda, Maria Marta; Illas, Francesc

    2013-11-01

    The interaction of acrolein and allyl alcohol with the Ag(111) surface has been studied by means of periodic density functional theory based calculations including explicitly dispersion terms. Different coverage values have been explored going from isolated adsorbed molecules to isolated dimers, interacting dimers or ordered overlayers. The inclusion of the dispersion terms largely affects the calculated values of the adsorption energy and also the distance between adsorbed molecule and the metallic surface but much less the adsorbate-adsorbate interactions. Owing to the large dipole moment of acrolein, the present calculations predict that at high coverage this molecule forms a stable extensive two-dimensional network on the surface, caused by the alignment of the adsorbate dipoles. For the case of allyl alcohol, dimers and complex networks exhibit similar stability.

  13. α-Sulfonyl succinimides: versatile sulfinate donors in Fe-catalyzed, salt-free, neutral allylic substitution.

    Science.gov (United States)

    Jegelka, Markus; Plietker, Bernd

    2011-09-01

    Allyl sulfones are versatile intermediates in organic chemistry. The presence of two distinct functional groups sets the stage for a plethora of subsequent transformations. However, despite these advantages the preparation of regioisomerically enriched sulfones is not easy. The use of sulfinate salts as nucleophiles in substitutions is frequently accompanied by side reactions such as π-bond migration, β-elimination, and so on. Herein we present a preparatively simple way to synthesize a variety of different aryl or alkyl allyl sulfones starting from readily accessible allylic carbonates. By employing aryl or alkyl α-sulfonyl succinimides as sulfinate synthons, mild and regioselective ipso substitution of diverse allylic carbonates was realized. PMID:21818793

  14. Construction of quaternary stereogenic carbon centers through copper-catalyzed enantioselective allylic cross-coupling with alkylboranes.

    Science.gov (United States)

    Hojoh, Kentaro; Shido, Yoshinori; Ohmiya, Hirohisa; Sawamura, Masaya

    2014-05-01

    A combination of an in situ generated chiral Cu(I) /DTBM-MeO-BIPHEP catalyst system and EtOK enabled the enantioselective SN 2'-type allylic cross-coupling between alkylborane reagents and γ,γ-disubstituted primary allyl chlorides with enantiocontrol at a useful level. The reaction generates a stereogenic quaternary carbon center having three sp(3) -alkyl groups and a vinyl group. This protocol allowed the use of terminal alkenes as nucleophile precursors, thus representing a formal reductive allylic cross-coupling of terminal alkenes. A reaction pathway involving addition/elimination of a neutral alkylcopper(I) species with the allyl chloride substrate is proposed. PMID:24668885

  15. Allyl thiourea as a corrosion inhibitor for cold rolled steel in H{sub 3}PO{sub 4} solution

    Energy Technology Data Exchange (ETDEWEB)

    Li Xianghong, E-mail: xianghong-li@163.com [Faculty of Science, Southwest Forestry University, Kunming 650224 (China) and Key Laboratory for Forest Resources Conservation and Use in the Southwest Mountains of China Ministry of Education, Southwest Forestry University, Kunming 650224 (China); Deng Shuduan [Faculty of Materials Engineering, Southwest Forestry University, Kunming 650224 (China); Fu Hui [Faculty of Science, Southwest Forestry University, Kunming 650224 (China)

    2012-02-15

    Highlights: Black-Right-Pointing-Pointer Allyl thiourea (ATU) acts as a good inhibitor for steel in 1.0 M H{sub 3}PO{sub 4}. Black-Right-Pointing-Pointer Inhibition efficiency increases slightly with the temperature at 0.2-0.5 mM. Black-Right-Pointing-Pointer The adsorption of ATU on steel surface obeys Langmuir adsorption isotherm. Black-Right-Pointing-Pointer ATU behaves as a mixed-type inhibitor. - Abstract: The inhibition effect of allyl thiourea (ATU) on the corrosion of cold rolled steel (CRS) in 1.0 M H{sub 3}PO{sub 4} solution at 20-50 Degree-Sign C was studied by weight loss, potentiodynamic polarisation, electrochemical impedance spectroscopy (EIS) and scanning electron microscopy (SEM) methods. The results show that ATU is a good inhibitor, and the maximum inhibition efficiency of 0.5 mM inhibitor is higher than 95% at all studied temperatures. The adsorption of ATU obeys Langmuir adsorption isotherm. Polarisation curves show that ATU behaves as a mixed-type inhibitor. EIS spectra exhibit one capacitive loop. The inhibition action is also evidenced by SEM.

  16. UV RADIATION INDUCED GRAFT COPOLYMERIZATION OF ALLYL ACETATE ONTO POLY(ETHYLENE TEREPHTHALATE) (PET) FILMS FOR FUEL CELL MEMBRANES

    Institute of Scientific and Technical Information of China (English)

    Mostak Ahmed; Mubarak A. Khan; Nazia Rahman; M. Anwar H. Khan

    2012-01-01

    Ultraviolet (UV)-induced graft copolymerization of allyl acetate (AA) monomer onto poly(ethylene terephthalate) (PET) films and the subsequent sulfonation on the monomer units in the grafting chain using chlorosulfonic acid (C1SO3H) were carried out to prepare proton exchange membranes (PEMs) for fuel cells.A maximum grafting value of 12.8% was found for 35 vol% allyl acetate after 3 h radiation time.Optimum concentration of ClSO3H was selected for the sulfonation reaction to be 0.05 mol/L based on the degree of sulfonation and the tensile strength studies of the membrane.The degree of sulfonation increased as the sulfonation reaction temperature and sulfonation time were increasing.The radiation grafting and the sulfonation have been confirmed by titrimetric and gravimetric analyses as well as FTIR spectroscopy.The maximum ion exchange capacity (IEC) of 0.04125 mmol g-1 was found at 12.1% degree of sulfonation and the maximum proton conductivity was found to be 0.035 S cm-1 at 30℃ and a relative humidity of 60%.The various physical and chemical properties of the PEMs such as water uptake,mechanical strength,thermal durability and oxidative stability were also studied.To investigate the suitability of the prepared membrane for fuel cell applications,its properties were compared with those of Nation 117.

  17. Allyl isothiocyanate enhances shelf life of minimally processed shredded cabbage.

    Science.gov (United States)

    Banerjee, Aparajita; Penna, Suprasanna; Variyar, Prasad S

    2015-09-15

    The effect of allyl isothiocyanate (AITC), in combination with low temperature (10°C) storage on post harvest quality of minimally processed shredded cabbage was investigated. An optimum concentration of 0.05μL/mL AITC was found to be effective in maintaining the microbial and sensory quality of the product for a period of 12days. Inhibition of browning was shown to result from a down-regulation (1.4-fold) of phenylalanine ammonia lyase (PAL) gene expression and a consequent decrease in PAL enzyme activity and o-quinone content. In the untreated control samples, PAL activity increased following up-regulation in PAL gene expression that could be linearly correlated with enhanced o-quinone formation and browning. The efficacy of AITC in extending the shelf life of minimally processed shredded cabbage and its role in down-regulation of PAL gene expression resulting in browning inhibition in the product is reported here for the first time. PMID:25863635

  18. Alternating current electroluminescent properties of zinc sulfide powders

    OpenAIRE

    Salimian, Alireza

    2012-01-01

    In order to investigate the alternating current electroluminescent properties of zinc sulfide powders the following experiments were conducted: synthesis of zinc sulfide phosphors (comprised of zinc, sulfur and copper dopant); thermal shocking of phosphor materials (sudden cooling, using liquid nitrogen, of phosphor particles heated up to 500oC) and analysis of their alternating current electroluminescent properties as well as studies of particle crystal structures by synchrotron and conventi...

  19. Pyrophoric nature of iron sulfides

    Energy Technology Data Exchange (ETDEWEB)

    Walker, R. [Univ. of Surrey, Guildford (United Kingdom). Dept. of Materials Science and Engineering; Steele, A.D.; Morgan, D.T.B. [Shell Research Centre Ltd., Chester (United Kingdom). Thornton Research Centre

    1996-05-01

    Hydrogen sulfide, often present in crude oil tankers, can react with rust to form various sulfides including mackinawite (FeS), greigite (Fe{sub 3}S{sub 4}), and pyrite (FeS{sub 2}). The tendency for these compounds to react with oxygen in air to form potentially explosive mixtures depends upon their morphology and the environmental conditions. The experimentally determined heat of oxidation of finely divided mackinawite was {minus}7.45 kJ/g. For samples with a larger particle size and smaller surface area the values measured were lower due to incomplete oxidation of the sulfide. All the sulfides produced, whether from magnetite or acicular, prismatic or spherical geothite, were approximately spherical in form. The heat of oxidation of greigite was found to be approximately {minus}2100 kJ/mol, and the heat of formation of greigite is approximately {minus}320 kJ/mol.

  20. Mechanochemical reduction of copper sulfide

    DEFF Research Database (Denmark)

    Balaz, P.; Takacs, L.; Jiang, Jianzhong; Soika, V.; Luxova, M.

    The mechanochemical reduction of copper sulfide with iron was induced in a Fritsch P-6 planetary mill, using WC vial filled with argon and WC balls. Samples milled for specific intervals were analyzed by XRD and Mossbauer spectroscopy. Most of the reaction takes place during the first 10 min of...... milling and only FeS and Cu are found after 60 min. The main chemical process is accompanied by phase transformations of the sulfide phases as a result of milling. Djurleite partially transformed to chalcocite and a tetragonal copper sulfide phase before reduction. The cubic modification of FeS was formed...... first, transforming to hexagonal during the later stages of the process. The formation of off-stoichiometric phases and the release of some elemental sulfur by copper sulfide are also probable....

  1. Co-settling of Chromite and Sulfide Melt Droplets and Trace Element Partitioning between Sulfide and Silicate Melts

    Science.gov (United States)

    Manoochehri, S.; Schmidt, M. W.; Guenther, D.

    2013-12-01

    Gravitational settling of immiscible, dense sulfide melt droplets together with other cumulate phases such as chromite, combined with downward percolation of these droplets through a cumulate pile, is thought to be one of the possible processes leading to the formation of PGE rich sulfide deposits in layered mafic intrusions. Furthermore some chromitite seams in the Merensky Reef (Bushveld Complex) are considered to be acting as a filter or barrier for further downward percolation of sulfide melts into footwall layers. To investigate the feasibility of such mechanical processes and to study the partitioning behavior of 50 elements including transition metals and REEs (but not PGEs) between a silicate and a sulfide melt, two separate series of high temperature (1250-1380 °C) centrifuge-assisted experiments at 1000 g, 0.4-0.6 GPa were conducted. A synthetic silicate glass with a composition representative of the parental magma of the Bushveld Complex (~ 55 wt% SiO2) was mixed with pure FeS powder. For the first series of experiments, 15 or 25 wt% natural chromite with average grain sizes of ~ 5 or 31 μm were added to a mixture of silicate glass and FeS (10 wt%) adding 1 wt% water. For the second series, a mixture of the same glass and FeS was doped with 50 trace elements. These mixtures were first statically equilibrated and then centrifuged. In the first experimental series, sulfide melt droplets settled together with, but did not segregate from chromite grains even after centrifugation at 1000 g for 12 hours. A change in initial chromite grain size and proportions didn't have any effect on segregation. Without chromite, the starting mixture resulted in the formation of large sulfide melt pools together with finer droplets still disseminated through the silicate glass and both at the bottom of the capsule. The incomplete segregation of sulfide melt is interpreted as being due to high interfacial energies between sulfide and silicate melts/crystals which hinder

  2. Study of atomic layer deposition of indium oxy-sulfide films for Cu(In,Ga)Se{sub 2} solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Bugot, Cathy, E-mail: cathy-externe.bugot@edf.fr [Institut de Recherche et Développement sur l' Energie Photovoltaïque (IRDEP, UMR 7174 CNRS-EDF-Chimie Paristech), Chatou (France); Schneider, Nathanaelle [Institut de Recherche et Développement sur l' Energie Photovoltaïque (IRDEP, UMR 7174 CNRS-EDF-Chimie Paristech), Chatou (France); Bouttemy, Muriel; Etcheberry, Arnaud [Institut Lavoisier de Versailles, UMR 8180 (CNRS-UVSQ), Versailles (France); Lincot, Daniel; Donsanti, Frédérique [Institut de Recherche et Développement sur l' Energie Photovoltaïque (IRDEP, UMR 7174 CNRS-EDF-Chimie Paristech), Chatou (France)

    2015-05-01

    This paper explores the growth mechanism of plasma enhanced atomic layer deposition of In{sub 2}(S,O){sub 3} films. The films were deposited using indium acetylacetonate (In(acac){sub 3}), hydrogen sulfide (H{sub 2}S) and Ar/O{sub 2} plasma as oxygen precursor. The films were characterized using X-ray reflectometry, spectrophotometry, energy dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy. To understand the growth mechanism and especially the interactions between Ar/O{sub 2} plasma and In{sub 2}(S,O){sub 3} growing film, in-situ analyses were performed using quadrupole mass spectrometry. In-situ qualitative analysis revealed good correlation between the species detected in vapor phase and thin film properties. High concentrations of atomic and molecular oxygen were measured in the vapor phase during O{sub 2} plasma pulses. Significant decrease of these species could be observed by varying the plasma power from 2600 to 300 W, while the optical band gap remained at high values (> 2.6 eV). The analysis of the O{sub 2}-free/Ar plasma process showed that some of these oxygen species originate either from the indium precursor or from the substrate surface. This study explains the high oxygen content of the films, and allows us to reduce and control it. Generally, this report provides keys to understand the effect of plasma reactivity for the elaboration of oxide based materials. - Highlights: • In{sub 2}(S,O){sub 3} films were synthesized by plasma enhanced atomic layer deposition. • Growth mechanism was studied via gas phase analysis by Quadrupole Mass Spectrometry. • Good correlation between the vapor phase species and thin films properties was observed. • The film compositions and band gaps can be controlled by varying the plasma power.

  3. Micro-PIXE Analysis of Trace Elements in Sulfides

    International Nuclear Information System (INIS)

    Micro-scale Proton-induced X-ray Emission (PIXE) of trace elements (TE) in sulfides provides insights into geologic processes including magmatic system evolution, ore forming events, and fluid-flow processes. The Los Alamos nuclear microprobe was used to determine TE concentrations and ratios in sulfides from diverse geologic environments including hydrothermal ore deposits, coal seams, and metamorphic rocks. Pyrrhotite (Po) from silicic volcanics contains high Cu and Ni; Po from the Clear Lake volcanic field has higher Mo than does Po from other volcanic fields. Coal pyrites contain high Cu, As, Se, Mo and Pb, and show high As/Se and Mo/Se in marine influenced sulfides from the Lower Kittanning coal, but not in other marine-influenced coals. Sulfides are amenable to micro-PIXE studies because of the difficulties in obtaining the homogeneous standards required for many other TE microanalytical techniques

  4. The hydrogen sulfide metabolite trimethylsulfonium is found in human urine

    Science.gov (United States)

    Lajin, Bassam; Francesconi, Kevin A.

    2016-06-01

    Hydrogen sulfide is the third and most recently discovered gaseous signaling molecule following nitric oxide and carbon monoxide, playing important roles both in normal physiological conditions and disease progression. The trimethylsulfonium ion (TMS) can result from successive methylation reactions of hydrogen sulfide. No report exists so far about the presence or quantities of TMS in human urine. We developed a method for determining TMS in urine using liquid chromatography-electrospray ionization-triple quadrupole mass spectrometry (LC-ESI-QQQ), and applied the method to establish the urinary levels of TMS in a group of human volunteers. The measured urinary levels of TMS were in the nanomolar range, which is commensurate with the steady-state tissue concentrations of hydrogen sulfide previously reported in the literature. The developed method can be used in future studies for the quantification of urinary TMS as a potential biomarker for hydrogen sulfide body pools.

  5. Development of bituminous coal liquefaction technology. ; Study using a small device (study on synthetic iron sulfide catalyst). Rekiseitan ekika gijutsu no kaihatsu. ; Kogata sochi ni yoru kenkyu (gosei ryukatetsu shokubai no kenkyu)

    Energy Technology Data Exchange (ETDEWEB)

    Ueda, S. (New Energy and Industrial Technology Development Organization, Tokyo (Japan))

    1993-09-01

    This paper reports the execution of device procurement and building construction of small equipment to manufacture synthetic iron sulfide for catalysts used in the NEDOL bituminous coal liquefaction process, carried out in the fiscal year 1992. To study synthetic iron sulfide catalysts manufactured by the dry manufacturing method, it has been planned to install small equipment with a catalyst manufacturing capacity of 10 kg/hr in a process supporting unit (PSU) plant. Major devices and electric measuring instruments have been procured. The construction work included civil engineering and building constructions for part of buildings to accommodate the whole equipment used in the sintering process and an electric room adjoining thereto. Because this small equipment serves also as a PSU exhaust gas treatment facility to treat exhaust gas containing SO2 produced as a sub-product in the sintering process, the PSU exhaust gas treatment process was modified, and the trial operation was carried out in September 1992. Technical standards and operation methods were discussed on each of the sintering process and the exhaust gas treatment process in the small equipment. A process instruction document, and an operation standard for steady operation, start-up and shutdown were prepared.

  6. Preferential desulfurization of dibenzyl sulfide by an isolated Gordonia sp. IITR100

    OpenAIRE

    Ahmad, Abrar; Chauhan, Ashok Kumar; Kushwaha, Hari Narayan; Javed, Saleem; Kumar, Ashwani

    2014-01-01

    Several organosulfur compounds are present in the crude oil, and are required to be removed before its processing into transport fuel. For this reason, biodesulfurization of thiophenic compounds has been studied extensively. However, studies on the sulfide compounds are scarce. In this paper, we describe desulfurization of a model sulfidic compound, dibenzyl sulfide (DBS) by an isolated Gordonia sp. IITR100. The reaction was accompanied with the formation of metabolites dibenzyl sulfoxide, di...

  7. Rapid formation of β-allyl substituted isotetronic acid derivatives via Claisen rearrangement using a microfludic device

    Institute of Scientific and Technical Information of China (English)

    Xia Ping Ma; Zhi Ming Li; Quan Rui Wang

    2011-01-01

    The thermal Claisen rearrangement of O-allyl substituted isotetronic acids 1 was successfully carried out within a glass microreactor operated with temperature at 150 ℃ and a flow rate of 1 mL/h. The strategy provides an efficient alternative way to β-allyl substituted isotetronic acid derivatives 2 in high yields with much accelerated reaction speed.

  8. Dicyano-Functionalized MCM-41-Supported Palladium Complex as An Efficient Catalyst for Allylation of Aldehydes and Ketones

    Institute of Scientific and Technical Information of China (English)

    ZHAO Hong; CAI Ming-Zhong

    2006-01-01

    Dicyano-functionalized MCM-41-supported palladium complex was prepared from dicyano-functionalized MCM-41 and palladium chloride. This complex exhibited high catalytic activity in the allylation of aldehydes and ketones with allylic chlorides in the presence of SnCl2. This polymeric palladium complex can be recovered and reused without noticeable loss of activity.

  9. Structure and reactivity of zinc sulfide precipitates formed in the presence of sulfate-reducing bacteria

    International Nuclear Information System (INIS)

    Highlights: → Biogenic zinc sulfides exhibit short-range structural order. → This structural order increases resistance to re-oxidation. → Dissolved Fe and Zn formed distinct sulfide phases. - Abstract: The biologically mediated formation of metal sulfide precipitates in anoxic sediments represents a potentially important mechanism for the sequestration of toxic metals. Current knowledge of the structure and reactivity of these biogenic metal sulfides is scarce, limiting the ability to effectively assess contaminant sequestration in, and remobilization from, these solids. In this study, SO4-reducing bacteria (Desulfovibrio sp.) were grown for 5 days in a high-SO4, minimal metal media amended with Zn at either 30 or 300 micromolar. Zinc speciation in the reactor solids was determined using X-ray absorption spectroscopy, and the results compared to spectra of known metal sulfide mineral phases and freshly formed metal sulfides synthesized through purely chemical processes. Biogenically mediated Zn sulfides showed significantly more short range crystallographic order than the abiotically prepared amorphous precipitates. The presence of dissolved Fe2+ at similar concentrations did not affect the nature of the Zn precipitates formed. The biogenic ZnS solids were also more resistant to re-oxidation than the chemical precipitates but more soluble than sphalerite mineral samples. These results suggest that Zn sulfides formed in anaerobic sediments are likely to be more resistant to re-oxidation than would be expected based on dissolution of Fe sulfides and/or sediment acid volatile sulfides.

  10. Synthesis of allyl dimethyl dehydroabietyl ammonium chloride and its surface activities

    International Nuclear Information System (INIS)

    Allyl dimethyl dehydroabietyl ammonium chloride (ADMDHAC) was synthesized from dehydroabietylamine (DHA) and allyl chloride. The synthesis was carried out in two steps. First, DHA was transformed into N,N-dimethyl dehydroabietyl amine (DMDHA) through Eschweiler-Clarke Reaction. Second, the ADMDHAC was obtained after the DMDHA had reacted with allyl chloride and recrystallized using a solvent composed of diethyl ether and ethanol. Critical micelle concentrations (cmc) of ADMDHAC at 25 degree C was found to be 2.851*10-4 mol.L-1, and its surface tension value at cmc (gamma cmc) was determined to be 30.6 mN.m-1, these data suggested that ADMDHAC could be used as a good alternative of benzalkonium chloride (BC). (author)

  11. How phenyl makes a difference: mechanistic insights into the ruthenium( ii )-catalysed isomerisation of allylic alcohols

    KAUST Repository

    Manzini, Simone

    2013-10-16

    [RuCl(η5-3-phenylindenyl)(PPh3)2] (1) has been shown to be a highly active catalyst for the isomerisation of allylic alcohols to the corresponding ketones. A variety of substrates undergo the transformation, typically with 0.25-0.5 mol% of catalyst at room temperature, outperforming commonly-used complexes such as [RuCl(Cp)(PPh3) 2] and [RuCl(η5-indenyl)(PPh3) 2]. Mechanistic experiments and density functional theory have been employed to investigate the mechanism and understand the effect of catalyst structure on reactivity. These investigations suggest a oxo-π-allyl mechanism is in operation, avoiding intermediate ruthenium hydride complexes and leading to a characteristic 1,3-deuterium shift. Important mechanistic insights from DFT and experiments also allowed for the design of a protocol that expands the scope of the transformation to include primary allylic alcohols. © 2013 The Royal Society of Chemistry.

  12. Allyl isothiocyanates and cinnamaldehyde potentiate miniature excitatory postsynaptic inputs in the supraoptic nucleus in rats.

    Science.gov (United States)

    Yokoyama, Toru; Ohbuchi, Toyoaki; Saito, Takeshi; Sudo, Yuka; Fujihara, Hiroaki; Minami, Kouichiro; Nagatomo, Toshihisa; Uezono, Yasuhito; Ueta, Yoichi

    2011-03-25

    Allyl isothiocyanates (AITC) and cinnamaldehyde are pungent compounds present in mustard oil and cinnamon oil, respectively. These compounds are well known as transient receptor potential ankyrin 1 (TRPA1) agonists. TRPA1 is activated by low temperature stimuli, mechanosensation and pungent irritants such as AITC and cinnamaldehyde. TRPA1 is often co-expressed in TRPV1. Recent study showed that hypertonic solution activated TRPA1 as well as TRPV1. TRPV1 is involved in excitatory synaptic inputs to the magnocellular neurosecretory cells (MNCs) that produce vasopressin in the supraoptic nucleus (SON). However, it remains unclear whether TRPA1 may be involved in this activation. In the present study, we examined the role of TRPA1 on the synaptic inputs to the MNCs in in vitro rat brain slice preparations, using whole-cell patch-clamp recordings. In the presence of tetrodotoxin, AITC (50μM) and cinnamaldehyde (30μM) increased the frequency of miniature excitatory postsynaptic currents without affecting the amplitude. This effect was significantly attenuated by previous exposure to ruthenium red (10μM), non-specific TRP channels blocker, high concentration of menthol (300μM) and HC-030031 (10μM), which are known to antagonize the effects of TRPA1 agonists. These results suggest that TRPA1 may exist at presynaptic terminals to the MNCs and enhance glutamate release in the SON. PMID:21266172

  13. Study of caffeine as corrosion inhibitors of carbon steel in chloride solution containing hydrogen sulfide using electrochemical impedance spectroscopy (EIS)

    Science.gov (United States)

    Solehudin, Agus; Berman, Ega Taqwali; Nurdin, Isdiriayani

    2015-09-01

    The corrosion behaviour of steel surface in the absence and presence of caffeine in 3.5% NaCl solution containing dissolved H2S gas is studied using electrochemical impedance spectroscopy (EIS). The experimental results of carbon steel corrosion in 3.5% NaCl solution containing 500 mg/l H2S at different caffeine concentrations showed that corrosion rate of carbon steel decreases with increasing of caffeine concentrations from 0 to 0,1 mmol/l. Whereas, the corrosion rate increase with increasing of caffeine concentrations from 1 to 10 mmol/l. It is clear that no inhibition efficiency increases with increasing inhibitor concentration. The optimum value of inhibition efficiency was 90% at a caffeine concentration of 0.1 mmol/l. This suggests that caffeine's performance as a corrosion inhibitor is more effective at a concentration of 0.1 mmol/l.

  14. The development of a potassium-sulfide glass fiber cell and studies on impurities in alkali metal-sulfur cells

    Science.gov (United States)

    Tsang, F. Y.

    1977-01-01

    Potassium sulfur rechargeable cells, having as the electrolyte the thin walls of hollow glass fibers made from permeable glass, were developed. The cells had short lives, probably due to the construction materials and impurities in the potassium. The effect of the impurities in the analogous NA-S system was studied. Calcium, potassium, and NaOH/oxide impurities caused increased resistance or corrosion of the glass fibers. For long lived cell operation, the Na must contain less than 1 ppm Ca and less than a few ppm of hydroxide/oxide. Up to 150 ppm K can be tolerated. After purification of the Na anolyte, cell lifetimes in excess of 1000 deep charge-discharge cycles or over 8 months on continuous cycling at 10-30 percent depth of discharge were obtained.

  15. Ultraviolet Photodissociation Dynamics of the Allyl Radical via the B̃(2)A1(3s), C̃(2)B2(3py), and Ẽ(2)B1(3px) Electronic Excited States.

    Science.gov (United States)

    Song, Yu; Lucas, Michael; Alcaraz, Maria; Zhang, Jingsong; Brazier, Christopher

    2015-12-17

    Ultraviolet (UV) photodissociation dynamics of jet-cooled allyl radical via the B̃(2)A1(3s), C̃(2)B2(3py), and Ẽ(2)B1(3px) electronically excited states are studied at the photolysis wavelengths from 249 to 216 nm using high-n Rydberg atom time-of-flight (HRTOF) and resonance-enhanced multiphoton ionization (REMPI) techniques. The photofragment yield (PFY) spectra of the H atom products are measured using both allyl chloride and 1,5-hexadiene as precursors of the allyl radical and show a broad peak centered near 228 nm, whereas the previous UV absorption spectra of the allyl radical peak around 222 nm. This difference suggests that, in addition to the H + C3H4 product channel, another dissociation channel (likely CH3 + C2H2) becomes significant with increasing excitation energy. The product translational energy release of the H + C3H4 products is modest, with the P(ET) distributions peaking near 8.5 kcal/mol and the fraction of the average translational energy in the total excess energy, ⟨fT⟩, in the range 0.22-0.18 from 249 to 216 nm. The P(ET)'s are consistent with production of H + allene and H + propyne, as suggested by previous experimental and theoretical studies. The angular distributions of the H atom products are isotropic, with the anisotropy parameter β ≈ 0. The H atom dissociation rate constant from the pump-probe study gives a lower limit of 1 × 10(8)/s. The dissociation mechanism is consistent with unimolecular decomposition of the hot allyl radical on the ground electronic state after internal conversion of the electronically excited state. PMID:26334360

  16. Asymmetric epoxidation of allylic alcohols catalyzed by vanadium-binaphthylbishydroxamic Acid complex.

    Science.gov (United States)

    Noji, Masahiro; Kobayashi, Toshihiro; Uechi, Yuria; Kikuchi, Asami; Kondo, Hisako; Sugiyama, Shigeo; Ishii, Keitaro

    2015-03-20

    A vanadium-binaphthylbishydroxamic acid (BBHA) complex-catalyzed asymmetric epoxidation of allylic alcohols is described. The optically active binaphthyl-based ligands BBHA 2a and 2b were synthesized from (S)-1,1'-binaphthyl-2,2'-dicarboxylic acid and N-substituted-O-trimethylsilyl (TMS)-protected hydroxylamines via a one-pot, three-step procedure. The epoxidations of 2,3,3-trisubstituted allylic alcohols using the vanadium complex of 2a were easily performed in toluene with a TBHP water solution to afford (2R)-epoxy alcohols in good to excellent enantioselectivities. PMID:25714329

  17. Highly selective palladium–benzothiazole carbene-catalyzed allylation of active methylene compounds under neutral conditions

    Directory of Open Access Journals (Sweden)

    Antonio Monopoli

    2015-06-01

    Full Text Available The Pd–benzothiazol-2-ylidene complex I was found to be a chemoselective catalyst for the Tsuji–Trost allylation of active methylene compounds carried out under neutral conditions and using carbonates as allylating agents. The proposed protocol consists in a simplified procedure adopting an in situ prepared catalyst from Pd2dba3 and 3-methylbenzothiazolium salt V as precursors. A comparison of the performance of benzothiazole carbene with phosphanes and an analogous imidazolium carbene ligand is also proposed.

  18. Allyl Isothiocyanate Inhibits Actin-Dependent Intracellular Transport in Arabidopsis thaliana

    Directory of Open Access Journals (Sweden)

    Bjørnar Sporsheim

    2015-12-01

    Full Text Available Volatile allyl isothiocyanate (AITC derives from the biodegradation of the glucosinolate sinigrin and has been associated with growth inhibition in several plants, including the model plant Arabidopsis thaliana. However, the underlying cellular mechanisms of this feature remain scarcely investigated in plants. In this study, we present evidence of an AITC-induced inhibition of actin-dependent intracellular transport in A. thaliana. A transgenic line of A. thaliana expressing yellow fluorescent protein (YFP-tagged actin filaments was used to show attenuation of actin filament movement by AITC. This appeared gradually in a time- and dose-dependent manner and resulted in actin filaments appearing close to static. Further, we employed four transgenic lines with YFP-fusion proteins labeling the Golgi apparatus, endoplasmic reticulum (ER, vacuoles and peroxisomes to demonstrate an AITC-induced inhibition of actin-dependent intracellular transport of or, in these structures, consistent with the decline in actin filament movement. Furthermore, the morphologies of actin filaments, ER and vacuoles appeared aberrant following AITC-exposure. However, AITC-treated seedlings of all transgenic lines tested displayed morphologies and intracellular movements similar to that of the corresponding untreated and control-treated plants, following overnight incubation in an AITC-absent environment, indicating that AITC-induced decline in actin-related movements is a reversible process. These findings provide novel insights into the cellular events in plant cells following exposure to AITC, which may further expose clues to the physiological significance of the glucosinolate-myrosinase system.

  19. Study of copper sulfide counter electrode on the performances of CdS/CdSe/ZnS-sensitized hierarchical TiO2 spheres quantum dots solar cells

    Science.gov (United States)

    Buatong, Nattha; Tang, I.-Ming; Pon-On, Weeraphat

    2015-07-01

    The effects of using copper sulfide (CuS) counter electrodes on the performances of solar cells made with CdS/CdSe/ZnS quantum dots co-sensitized onto hierarchical TiO2 spheres (HTS) used as photoelectrode is reported. The HTS in the QDSSCs is composed of an assembly of numerous TiO2 spheres made by the solvolthermal method. The photoelectrical performance of HTS/CdS/CdSe/ZnS coupled to CuS counter electrode was compared to those coupled to Pt CE. The HTS/CdS/CdSe/ZnS coupled to the CuS CE showed the highest power conversion efficiency η (of 1.310 %.) which is significantly higher than those using a standard Pt CE (η = 0.374%) (3.50 fold). This higher efficiency is the results of the higher electrocatalytic activities when the copper sulfide CEs is used.

  20. Study and properties of materials. Dry corrosion of materials. Industrial cases: sulfidation, nitridation; Etude et proprietes des metaux. Corrosion seche des metaux. Cas industriels: sulfuration, nitruration

    Energy Technology Data Exchange (ETDEWEB)

    Antoni, L. [Ecole Nationale Superieure d' Electrochimie et d' Electrometallurgie, 38 - Grenoble (France)

    2002-12-01

    This paper presents the corrosion mechanisms of materials for the sulfidation and the nitridation. The sulfur is one of the most corrosive pollutants existing in the high temperature industrial processes. The nitridation is a surface hardening processing but also a corrosion mode. The nitridation becomes a problem at high temperature, if the oxygen content in the atmosphere is insufficient or when the nitrogen exists at the atomique state. (A.L.B.)

  1. Antifoaming materials in G.S. (Girlder sulfide) heavy water plants. Thermical stability. Pt. 2

    International Nuclear Information System (INIS)

    In Girlder sulfide (G.S.) heavy water plants hydrogen sulfide-water systems are inherentely foaming, so the adding of antifoaming materials is of great importance. These may be of high volatility, pyrolizable or chemically unstable in plant operation conditions (water and hydrogen sulfide at 2 MPa, up to 230 deg C). About twenty commercial surfactants were studied from the point of view of their thermical stability. (Author)

  2. Research of the Plasma Sulfide Layer Formed on the Nitrocarburizing Layer

    Institute of Scientific and Technical Information of China (English)

    LI Xin; MA Shi-ning; HU Chun-hua; QIU Ji; HUANG Yuan-lin

    2004-01-01

    Low-temperature sulfurizing after nitrocarburizing are compared with only low-temperature sulfurizing on the surface of CrMoCu alloyed cast iron, the surface morphologies and microstructures are investigated by SEM and EDS.Results show that under proper treatment parameters, there are sulfide layer on both of the surfaces, and can more easily obtain sulfide layers on the surface of nitrocarburizing. Forming mechanism of sulfides were also studied elementarily.

  3. Marine mineral resources The Global Rare Element Endowment of Seafloor Massive Sulfide Deposits

    OpenAIRE

    Monecke, Thomas; Petersen, Sven; Hannington, Mark D.; Grant, Hannah

    2015-01-01

    Over the past three decades, a large number of seafloor hydrothermal vent sites and associated sulfide deposits have been discovered in the worlds' oceans. Geochemical analysis of samples collected from vent sites worldwide suggests that seafloor sulfide deposits may contain significant base and precious metal concentrations. The present study provides the first estimate of the global rare metal endowment of these deposits. It is shown that seafloor sulfide accumulations can contain elevated ...

  4. Solvent-Controlled, Tunable β-OAc and β-H Elimination in Rh(III)-Catalyzed Allyl Acetate and Aryl Amide Coupling via C-H Activation.

    Science.gov (United States)

    Dai, Huimin; Yu, Chao; Wang, Zihao; Yan, Hong; Lu, Changsheng

    2016-07-15

    The Heck reaction between arenes and allyl acetate has led to cinnamyl derivatives and allyl products depending on the regioselectivity of β-elimination. The regioselectivity can be controlled by the solvent in the Rh(III)-catalyzed arene-allyl acetate coupling via C-H activation: (1) in THF, cinnamyl derivatives via β-H elimination were generated; (2) in MeOH, allyl products via β-OAc elimination were produced. Both routes have advantages such as excellent γ-selectivity toward allyl acetate, good to excellent yields, and broad substrate scope. PMID:27351917

  5. Enhanced performance of denitrifying sulfide removal process under micro-aerobic condition

    International Nuclear Information System (INIS)

    The denitrifying sulfide removal (DSR) process with bio-granules comprising both heterotrophic and autotrophic denitrifiers can simultaneously convert nitrate, sulfide and acetate into di-nitrogen gas, elementary sulfur and carbon dioxide, respectively, at high loading rates. This study determines the reaction rate of sulfide oxidized into sulfur, as well as the reduction of nitrate to nitrite, would be enhanced under a micro-aerobic condition. The presence of limited oxygen mitigated the inhibition effects of sulfide on denitrifier activities, and enhanced the performance of DSR granules. The advantages and disadvantages of applying the micro-aerobic condition to the DSR process are discussed.

  6. Synthesis of furan from allenic sulfide derivatives

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    In this paper, we report the synthesis of furan derivatives from allenic sulfides. By the reaction with NaH, β-Hydroxyl allenic sulfides were found to generate furan products in excellent yields with the removal of phenylthio group. β-Aldehyde allenic sulfides were found to give similar furan products with one more substituent when treated with additional nucleophilic reagents. β-ketone allenic sulfides can also cyclize to give furan derivatives with the promotion of P2O5.

  7. Synthesis of furan from allenic sulfide derivatives

    Institute of Scientific and Technical Information of China (English)

    PENG LingLing; ZHANG Xiu; MA Jie; ZHONG ZhenZhen; ZHANG Zhe; ZHANG Yan; WANG JianBo

    2009-01-01

    In this paper, we report the synthesis of furan derivatives from allenic sulfides. By the reaction with NaH.,β-Hydroxyl allenic sulfides were found to generate furan products in excellent yields with the removal of phenylthio group.β-Aldehyde allenic sulfides were found to give similar furan products with one more substituent when treated with additional nucleophilic reagents. β-ketone allenic sulfides can also cyclize to give furan derivatives with the promotion of P2O5.

  8. Spontaneous electrochemical treatment for sulfur recovery by a sulfide oxidation/vanadium(V) reduction galvanic cell.

    Science.gov (United States)

    Kijjanapanich, Pimluck; Kijjanapanich, Pairoje; Annachhatre, Ajit P; Esposito, Giovanni; Lens, Piet N L

    2015-02-01

    Sulfide is the product of the biological sulfate reduction process which gives toxicity and odor problems. Wastewaters or bioreactor effluents containing sulfide can cause severe environmental impacts. Electrochemical treatment can be an alternative approach for sulfide removal and sulfur recovery from such sulfide rich solutions. This study aims to develop a spontaneous electrochemical sulfide oxidation/vanadium(V) reduction cell with a graphite electrode system to recover sulfide as elemental sulfur. The effects of the internal and external resistance on the sulfide removal efficiency and electrical current produced were investigated at different pH. A high surface area of the graphite electrode is required in order to have as less internal resistance as possible. In this study, graphite powder was added (contact area >633 cm(2)) in order to reduce the internal resistance. A sulfide removal efficiency up to 91% and electrical charge of more than 400 C were achieved when using five graphite rods supplemented with graphite powder as the electrode at an external resistance of 30 Ω and a sulfide concentration of 250 mg L(-1). PMID:25463589

  9. 30 CFR 250.808 - Hydrogen sulfide.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 2 2010-07-01 2010-07-01 false Hydrogen sulfide. 250.808 Section 250.808... OPERATIONS IN THE OUTER CONTINENTAL SHELF Oil and Gas Production Safety Systems § 250.808 Hydrogen sulfide. Production operations in zones known to contain hydrogen sulfide (H2S) or in zones where the presence of...

  10. 30 CFR 250.490 - Hydrogen sulfide.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 2 2010-07-01 2010-07-01 false Hydrogen sulfide. 250.490 Section 250.490... OPERATIONS IN THE OUTER CONTINENTAL SHELF Oil and Gas Drilling Operations Hydrogen Sulfide § 250.490 Hydrogen... black lettering as follows: Letter height Wording 12 inches Danger. Poisonous Gas. Hydrogen Sulfide....

  11. 30 CFR 250.604 - Hydrogen sulfide.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 2 2010-07-01 2010-07-01 false Hydrogen sulfide. 250.604 Section 250.604... OPERATIONS IN THE OUTER CONTINENTAL SHELF Oil and Gas Well-Workover Operations § 250.604 Hydrogen sulfide. When a well-workover operation is conducted in zones known to contain hydrogen sulfide (H2S) or...

  12. 30 CFR 250.504 - Hydrogen sulfide.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 2 2010-07-01 2010-07-01 false Hydrogen sulfide. 250.504 Section 250.504... OPERATIONS IN THE OUTER CONTINENTAL SHELF Oil and Gas Well-Completion Operations § 250.504 Hydrogen sulfide. When a well-completion operation is conducted in zones known to contain hydrogen sulfide (H2S) or...

  13. α-Regioselective Barbier Reaction of Carbonyl Compounds and Allyl Halides Mediated by Praseodymium.

    Science.gov (United States)

    Wu, San; Li, Ying; Zhang, Songlin

    2016-09-01

    The first utility of praseodymium as a mediating metal in the Barbier reaction of carbonyl compounds with allyl halides was reported in this paper. In contrast to the traditional metal-mediated or catalyzed Barbier reactions, exclusive α-adducts were obtained in this one-pot reaction with a broad scope of substrates and feasible reaction conditions. PMID:27490708

  14. Catalytic asymmetric allylation of aliphatic aldehydes by chiral bipyridine N,N'-dioxides

    Czech Academy of Sciences Publication Activity Database

    Hrdina, R.; Boyd, T.; Valterová, Irena; Hodačová, Jana; Kotora, Martin

    -, č. 20 (2008), s. 3141-3144. ISSN 0936-5214 Grant ostatní: GA MŠk(CZ) LC06070 Institutional research plan: CEZ:AV0Z40550506 Keywords : allylations * aldehydes * Lewis base * asymmetric catalysis * solvent effect Subject RIV: CC - Organic Chemistry Impact factor: 2.659, year: 2008

  15. Synthesis of telechelic vinyl/allyl functional siloxane copolymers with structural control

    DEFF Research Database (Denmark)

    Madsen, Frederikke Bahrt; Javakhishvili, Irakli; Jensen, Rasmus Egekjær;

    2014-01-01

    Multifunctional siloxane copolymers with terminal vinyl or allyl functional groups are synthesised through the borane-catalysed polycondensation of hydrosilanes and alkoxysilanes. Copolymers of varying mole- cular weights ( M ̄ w =13200 – 70 300 g mol − 1 ), spatially well-distributed functional ...

  16. Allylic and benzylic sp3 C-H oxidation in water.

    Science.gov (United States)

    Ang, Wei Jie; Lam, Yulin

    2015-01-28

    A copper-catalyzed method for the oxidation of allylic and benzylic sp(3) C-H by aqueous tert-butyl hydroperoxide (T-Hydro) in water using a recyclable fluorous ligand has been developed. The reaction procedure is tolerant to additional functional groups and the fluorous ligand could be reused with little loss of catalytic activity. PMID:25412371

  17. Polystyrene-supported Selenides and Selenoxide:Versatile Routes to Synthesize Allylic Alcohols

    Institute of Scientific and Technical Information of China (English)

    Wei Ming XU; You Chu ZHANG; Xian HUANG

    2003-01-01

    Several polystyrene-supported selenides and selenoxide have been prepared firstly. These novel reagents were treated with LDA to produce selenium stabilized carbanions, which reacted with aldehydes and alkyl halides, followed by selenoxide syn-elimination and [2,3] sigmatropic rearrangement respectively to give Z-allylic alcohols stereoselectively.

  18. In(OTf)3 catalyzed allylation reaction of imines with tetraallyltin

    Institute of Scientific and Technical Information of China (English)

    Xiao Ning Wei; Ling Yan Liu; Bing Wang; Wei Xing Chang; Jing Li

    2009-01-01

    In the presence of catalytic amount of In(OTf)3 (10 mol%), a series of aldimines reacted with tetraallyltin in a 2:1 molar ratio to afford the corresponding homoallylic amines in good yields. The good atom efficiency was achieved under mild reaction conditions and a new protocol (allyl)4Sn/In(OTf)3 for simple imines was developed.

  19. Syntheses of a Flobufen Metabolite and Dapoxetine Based on Enantioselective Allylation of Aromatic Aldehydes

    Czech Academy of Sciences Publication Activity Database

    Hessler, F.; Korotvička, A.; Nečas, D.; Valterová, Irena; Kotora, M.

    2014-01-01

    Roč. 2014, č. 12 (2014), s. 2543-2548. ISSN 1434-193X Grant ostatní: GA ČR(CZ) GAP207/11/0587 Institutional support: RVO:61388963 Keywords : synthetic methods * asymmetric catalysis * organocatalysis * allylation * aldehydes * enantioselectivity Subject RIV: CC - Organic Chemistry Impact factor: 3.065, year: 2014

  20. Organocatalytic asymmetric allylic amination of Morita–Baylis–Hillman carbonates of isatins

    Directory of Open Access Journals (Sweden)

    Hang Zhang

    2012-08-01

    Full Text Available The investigation of a Lewis base catalyzed asymmetric allylic amination of Morita–Baylis–Hillman carbonates derived from isatins afforded an electrophilic pathway to access multifunctional oxindoles bearing a C3-quaternary stereocenter, provided with good to excellent enantioselectivity (up to 94% ee and in high yields (up to 97%.

  1. Method of preparing water purification membranes. [polymerization of allyl amine as thin films in plasma discharge

    Science.gov (United States)

    Hollahan, J. R.; Wydeven, T. J., Jr. (Inventor)

    1974-01-01

    Allyl amine and chemically related compounds are polymerized as thin films in the presence of a plasma discharge. The monomer compound can be polymerized by itself or in the presence of an additive gas to promote polymerization and act as a carrier. The polymerized films thus produced show outstanding advantages when used as reverse osmosis membranes.

  2. Rationalizing Ring-Size Selectivity in Intramolecular Pd-Catalyzed Allylations of Resonance-Stabilized Carbanions

    DEFF Research Database (Denmark)

    Norrby, Per-Ola; Mader, Mary M.; Vitale, Maxime; Prestat, Guillaume; Poli, Giovanni

    2003-01-01

    Computational methods were applied to the Pd-catalyzed intramolecular allylations of resonance-stabilized carbanions obtained from amide and ketone substrates, with the aim of rationalizing the endo- vs. exo-selectivity in the cyclizations. In addition, ester substrates were prepared and subjecte...

  3. Oxidative allylic rearrangement of cycloalkenols: Formal total synthesis of enantiomerically pure trisporic acid B

    Directory of Open Access Journals (Sweden)

    Bernhard Westermann

    2011-04-01

    Full Text Available Enantiomerically highly enriched unsaturated β-ketoesters bearing a quaternary stereocenter can be utilized as building blocks for the synthesis of natural occurring terpenes, i. a., trisporic acid and its derivatives. An advanced building block has been synthesized in a short reaction sequence, which involves an oxidative allylic rearrangement initiated by pyridinium dichromate (PDC as the key step.

  4. Enantioselective copper catalyzed allylic alkylation using Grignard reagents; Applications in synthesis

    NARCIS (Netherlands)

    Zijl, Anthoni Wouter van

    2009-01-01

    Enantioselective copper catalyzed allylic alkylation is a powerful carbon-carbon bond forming reaction. In this thesis the development of a new catalyst for the use of Grignard reagents in this reaction is described. This catalyst is based on copper and the ligand Taniaphos. The high regio- and enan

  5. Phototrophic sulfide oxidation: environmental insights and a method for kinetic analysis

    Directory of Open Access Journals (Sweden)

    Thomas E Hanson

    2013-12-01

    Full Text Available Previously, we presented data that indicated microbial sulfide oxidation would out-compete strictly chemical, abiotic sulfide oxidation reactions under nearly all conditions relevant to extant ecosystems (Luther et al., 2011. In particular, we showed how anaerobic microbial sulfide oxidation rates were several orders of magnitude higher than even metal catalyzed aerobic sulfide oxidation processes. The fact that biotic anaerobic sulfide oxidation is kinetically superior to abiotic reactions implies that nearly all anaerobic and sulfidic environments should host microbial populations that oxidize sulfide at appreciable rates. This was likely an important biogeochemical process during long stretches of euxinia in the oceans suggested by the geologic record. In particular, phototrophic sulfide oxidation allows the utilization of carbon dioxide as the electron acceptor suggesting that this process should be particularly widespread rather than relying on the presence of other chemical oxidants. Using the Chesapeake Bay as an example, we argue that phototrophic sulfide oxidation may be more important in many environments than is currently appreciated. Finally, we present methodological considerations to assist other groups that wish to study this process.

  6. Selenium content of sulfide ores related to ophiolites of Greece.

    Science.gov (United States)

    Economou-Eliopoulos, M; Eliopoulos, D G

    1998-01-01

    Several deposits of sulfide mineralization have been described in the ophiolites of Greece. Based on their mineralogical and chemical composition and the host rocks, two types can be distinguished: (1) the Fe-Cu-Ni-Co type consisting of pyrrhotite, chalcopyrite, Co-pentlandite, pyrite, magnetite + arsenides, +/- chromite, hosted in serpentinites, gabbros or diabases, which have variable geochemical characteristics, and (2) sulfide mineralization of the Cyprus type containing variable proportions of pyrite, chalcopyrite, bornite, and sphalerite. The spatial association with shear zones and fault systems, which is a common feature in both types of mineralization, provided the necessary permeability for the circulation of the responsible mineralized hydrothermal fluids. The selenium (Se) content in representative samples of both types of mineralization from the ophiolites of Pindos (Kondro, Perivoli, and Neropriona), Othrys (Eretria and A. Theodoroi), Veria (Trilofon), and Argolis (Ermioni) shows a wide variation. The highest values of Se (130 to 1900 ppm) were found in massive Fe-Cu sulfide ores from Kondro, in particular the Cu-rich portions (average 1300 ppm Se). The average values of Se for the Othrys sulfides are low (< 40 ppm Se). The Se content in a diabase breccia pipe (50 x 200 m) with disseminated pyrite mineralization (Neropriona) ranges from < 1 to 35 ppm Se. The highest values were noted in strongly altered samples that also exhibited a significant enrichment in platinum (1 ppm Pt). Sulfide mineralization (irregular to lens-like masses and stringers) associated with magnetite, hosted in gabbros exposed in the Perivoli area (Tsouma hill), shows a content ranging from 40 to 350 ppm Se. The distribution of Se in the studied type of the sulfide mineralization may be of genetic significance, indicating that the Se level, which often is much higher than in typical magmatic sulfides related to mafic-ultramafic rocks (average 90-100 ppm Se), may positively affect

  7. 21 CFR 172.515 - Synthetic flavoring substances and adjuvants.

    Science.gov (United States)

    2010-04-01

    ...-hexadienoate. Allyl sulfide. Allyl tiglate; allyl trans-2-methyl-2-butenoate. Allyl 10-undecenoate. Ammonium isovalerate. Ammonium sulfide. Amyl alcohol; pentyl alcohol. Amyl butyrate. α-Amylcinnamaldehyde. α... hexanoate. Butyl p-hydroxybenzoate. Butyl isobutyrate. Butyl isovalerate. Butyl lactate. Butyl...

  8. N-allyl epiderpride: An extremely potent SPECT radioligand for the dopamine D2 receptor

    Energy Technology Data Exchange (ETDEWEB)

    Kessler, R.M.; Mason, N.S.; Ansari, M.S. [Vanderbilt Univ., Nashville, TN (United States)] [and others

    1994-05-01

    We have previously reported that epidepride is a potent (K{sub D} 24pM) and specific SPECT radioligand for the dopamine D2 receptor which can be used to study striatal and extrastriatal dopamine D2 receptors in man. We have synthesized and evaluated the N-allyl analogue of epiderpride (APID) as a potential SPECT radioligand for the dopamine D2 receptor. In comparison to epidepride it is even more potent at the dopamine D2 receptor, the K{sub D} for APID being 11 frontal cortical homogenate. The lipophilicity, evaluated using the log kw pH 7.5, was 2.9 versus 2.05 for epidepride. Competitive binding studies using rat striatal, hippocampal and frontal cortical homogenates showed high affinity for only dopamine D2 like cerebellar ratio of 275:1 at 320 minutes post injection-similar to that seen with epidepride, but with nearly four times higher brain uptake. Of interest was the off-rate from the dopamine D2 receptor; it was 0.0046 min{sup -1} in vitro at 25{degrees}C-corresponding to an t 1/2 of 150 minutes. Studies in rhesus monkeys show an in vivo off rate (following 2.5 mg/kg raclopride IV) of about 0.0082 min{sup -1} seen that with epidepride. SPECT studies in rhesus monkeys reveal APID is a promising SPECT radioligand that appears to be similar to epidepride, but with higher brain uptake due to its more optimal lipophilicity for entry into brain.

  9. New copolymer of acrylamide with allyl methacrylate and its capacity for the removal of azo dyes

    Directory of Open Access Journals (Sweden)

    Yeliz Yildirim

    2015-04-01

    Full Text Available The copolymerization reactions of Acrylamide (AA with the different mole ratios of allyl methacrylate (AMA such as 25/75, 50/50 and 75/25 were studied by radical polymerization under argon atmosphere using 2,2’-Azobis (isobutyronitri1e (AIBN as initiator. The copolymers were characterized with Fourier transform infrared spectroscopy (FTIR and thermogravimetric analysis (TG. FTIR spectra showed that the C=O, C-N and N-H groups in copolymers remained during the copolymerization. It is concluded from the thermograms that Poly(AA-co-AMA copolymers which contained different ratios of monomer and comonomer exhibit similar thermal behavior. Adsorption capacity, kinetic and isotherm studies of Direct Brown 2 onto the copolymers have been evaluated. Different factors such as the monomer ratio, pH, initial dye concentration, copolymer dosage and contact time affecting the removal process were studied. It was found that the adsorption process agreed with the Freundlich and Dubinin-Raduskevich model and the adsorption of Direct Brown 2 depended on the acrylamide content and pH of the solution. The standard Gibb’s free energy was determined as - 14.7 kJ/mol, which means that adsorption occurred spontaneously and the process is feasible. Increasing the acrylamide content led to increased adsorption of Direct Brown 2 on the copolymer. Moreover, adsorption kinetic studies showed that the adsorption followed a pseudo-second-order kinetic model, indicating that the chemical adsorption was the rate-limiting step. These results show that Poly(AA-co-AMA can be used as adsorbent for water pollutants such as Direct Brown 2 and has potential applications in related industrial and environmental areas.

  10. Enhanced durability and reactivity for zinc ferrite desulfurization sorbent. Volume 2, Single particle kinetic studies of sulfidation and regeneration reactions of candidate zinc ferrite sorbents

    Energy Technology Data Exchange (ETDEWEB)

    Silaban, A.; Harrison, D.P. [Louisiana State Univ., Baton Rouge, LA (United States). Dept. of Chemical Engineering

    1989-05-02

    AMAX Research & Development Center (AMAX R&D) has been investigating methods for enhancing the reactivity and durability of the zinc ferrite desulfurization sorbent. Zinc ferrite sorbents are intended for use in desulfurization of hot coal gas in integrated gasification combined cycle (IGCC) or molten carbonate fuel cell (MCFC) applications. For the present program, the reactivity of the sorbent may be defined as its sulfur sorption capacity at the breakthrough point and at saturation in a bench-scale, fixed-bed reactor. Durability may be defined as the ability of the sorbent to maintain important physical characteristics such as size, strength, and specific surface area during 10 cycles of sulfidation and oxidation.

  11. Formation and evolution stages of gold rich Barika massive sulfide deposit, east of Sardasht, northern Sanandaj-Sirjan zone: based on structural, textural and fluid inclusion studies

    Directory of Open Access Journals (Sweden)

    Hossein Ali Tajeddin

    2010-05-01

    Full Text Available Barika gold (and silver rich massive sulfide deposit is located 18 km east of Sardasht, north western part of Sanandaj-Sirjan metamorphic zone. Rock units outcropped in this area are Cretaceous metamorphosed volcano-sedimentary rocks in green schist facies, and include association of meta-andesite, meta-tuffite, phyllite and slate rocks, where the meta-andesitic unit (Kmv1 is host rock to the deposit. Barika deposit is composed of stratiform ore and stringer zone. Stratiform part contains massive and banded sulfide and barite associated with subordinary silica bands underlain by stringer silicic zone. The massive and banded ore is surrounded by an extensive zone of silicic stringer veins and disseminated mineralization within strongly altered and deformed andesitic volcanic rocks. Ore mineral assemblages in stratiform part of the deposit are quite variable and consist of pyrite, sphalerite, galena, stibnite, a variety of sulfosalt minerals and gold (electrum. Ore mineral assemblages in silicic veins in the stringer zone are simpler and consist of pyrite, galena, sphalerite, tetrahedrrite and trace chalcopyrite. Average gold and silver grades in stratiform ore are 8.3 and 420 g/t respectively and in silicic stringer veins are 0.7 and 30 g/t. Base metal content in both parts of the deposit are less than 1%. Based on our research, Barika is an immature Kuroko type massive sulfide deposit, which contains only black ore. The Barika deposit underwent low-grade metamorphism and high grade deformation after the ore deposition event. Geologic processes appear to control the mode of occurrence of gold in the deposit. In synvolcanism stage, deposition of a gold–bearing low temperature (140-200°C and low salinity (1-9.6 wt% NaCl hydrothermal fluid formed a Kuroko black ore type deposit. In the stage of mineralization, invisible gold was concentrated in framboidal pyrite and other sulfide minerals. The main effect of progressive metamorphism (D1 on gold

  12. Gold(I)-Catalyzed Intramolecular Hydroamination of N-Allylic,N′-Aryl Ureas to form Imidazolidin-2-ones

    OpenAIRE

    Li, Hao; Song, Feijie; Widenhoefer, Ross A.

    2011-01-01

    Treatment of N-allylic,N′-aryl ureas with a catalytic 1:1 mixture of di-tert-butyl-o-biphenylphoshphine gold(I) chloride and silver hexafluorophosphate (1 mol %) in chloroform at room temperature led to 5-exo hydroamination to form the corresponding imidazolidin-2-ones in excellent yield. In the case of N-allylic ureas that possessed an allylic alkyl, benzyloxymethyl, or acetoxymethyl substituent, gold(I)-catalyzed 5-exo hydroamination leads to formation of the corresponding trans-3,4-disubst...

  13. Gold(I)-Catalyzed Intramolecular Hydroamination of N-Allylic,N'-Aryl Ureas to form Imidazolidin-2-ones.

    Science.gov (United States)

    Li, Hao; Song, Feijie; Widenhoefer, Ross A

    2011-04-18

    Treatment of N-allylic,N'-aryl ureas with a catalytic 1:1 mixture of di-tert-butyl-o-biphenylphoshphine gold(I) chloride and silver hexafluorophosphate (1 mol %) in chloroform at room temperature led to 5-exo hydroamination to form the corresponding imidazolidin-2-ones in excellent yield. In the case of N-allylic ureas that possessed an allylic alkyl, benzyloxymethyl, or acetoxymethyl substituent, gold(I)-catalyzed 5-exo hydroamination leads to formation of the corresponding trans-3,4-disubstituted imidazolidin-2-ones in excellent yield with ≥50:1 diastereoselectivity. PMID:21709731

  14. Stratospheric carbonyl sulfide (OCS) burden

    Science.gov (United States)

    Kloss, Corinna; Walker, Kaley A.; Deshler, Terry; von Hobe, Marc

    2015-04-01

    An estimation of the global stratospheric burden of carbonyl sulfide (OCS) calculated using satellite based measurements from the Atmospheric Chemistry Experiment - Fourier Transform Spectrometer (ACE-FTS) will be presented. OCS is the most abundant sulfur containing gas in the atmosphere in the absence of volcanic eruptions. With a long lifetime of 2-6 years it reaches the stratosphere where it is photolyzed and the sulfur oxidized and condensed to aerosols, contributing to the stratospheric aerosol layer. The aerosol layer is the one factor of the middle-atmosphere with a direct impact on the Earth's climate by scattering incoming solar radiation back to space. Therefore it is crucial to understand and estimate the different processes and abundances of the species contributing to the aerosol layer. However, the exact amount of OCS in the stratosphere has not been quantified yet. A study on the OCS mixing ratio distribution based on ACE-FTS data has already been made by Barkley et al. (2008), also giving an estimation for the total atmospheric OCS mass. ACE-FTS is an infrared solar occultation spectrometer providing high- resolution profile observations since 2004. In the scope of this work the focus lies on the stratospheric OCS burden, calculated by integrating the ACE profiles. A global overview on the stratospheric OCS amount in the past and present based on the ACE data as well as a look at regional and seasonal variability will be given. Furthermore, the results of this work will be useful for further studies on OCS fluxes and lifetimes, and in quantifying the contribution of OCS to the global stratospheric sulfur burden. Barkley et al., 2008, Geophys. Res. Lett., 35, L14810.

  15. Electrochemical Behavior Of Copper Electrode In Potassium Sulfide Solutions

    Directory of Open Access Journals (Sweden)

    I. Zaafarany

    2014-09-01

    Full Text Available The electro chemical behavior of copper electrode in 2M potassium sulfide solution was studied using cyclic voltammograms and potentiostatic polarization techniques. The morphology studies were applied using scanning electron microscope (SEM and energy dispersive analysis of X-rays (EDAX and X-ray powder diffraction. Three anodic peaks were observed in the anodic scan of cyclic voltammograms. SEM and EDAX analysis show the formation of an anodic copper sulfide layer on the surface of copper. Chemical sulfidization of the copper shown to be an important layer growth pathway. The sulfide layers do not passivate copper and the formation of passivating oxide layer is suppressed. The sulfide layer on copper has a Cu2S stoichiometry with roxybyite and digenite structure and it grows by a nucleation. A small patches were consistent with a CuS composition. The formation of KCu7S4 or any other ternary compound could not be observed. Only a presumable polysulfide phase very similar to KCuS4 could be detected.

  16. Does 1-Allyl-3-methylimidazolium chloride Act as a Biocompatible Solvent for Stem Bromelain?

    Science.gov (United States)

    Jha, Indrani; Bisht, Meena; Venkatesu, Pannuru

    2016-06-30

    The broader scope of ILs in chemical sciences particularly in pharmaceutical, bioanalytical and many more applications is increasing day by day. Hitherto, a very less amount of research is available in the depiction of conformational stability, activity, and thermal stability of enzymes in the presence of ILs. In the present study, the perturbation in the structure, stability, and activity of stem bromelain (BM) has been observed in the presence of 1-allyl-3-methylimidazolium chloride ([Amim][Cl]) using various techniques. This is the first report in which the influence of [Amim][Cl] has been studied on the enzyme BM. Fluorescence spectroscopy has been utilized to map out the changes in the environment around tryptophan (Trp) residues of BM and also to discuss the variations in the thermal stability of BM as an outcome of its interaction with the IL at different concentrations. Further, the work delineates the denaturing effect of high concentration of IL on enzyme structure and activity. It dictates the fact that low concentrations (0.01-0.10 M) of [Amim][Cl] are only changing the structural arrangement of the protein without having harsh consequences on its activity and stability. However, high concentrations of IL proved to be totally devastating for both activity and stability of BM. The observed decrease in the stability of BM at high concentration may be due to the combined effect of cation and anion interactions with the protein residues. The present work is successful in dictating the probable mechanism of interaction between BM and [Amim][Cl]. These results can prove to be fruitful in the studies of enzymes in aqueous IL systems since the used IL is thermally stable and nonvolatile in nature thereby providing a pathway of alteration in the activity of enzymes in potentially green systems. PMID:27268069

  17. Atomic layer deposition of aluminum sulfide thin films using trimethylaluminum and hydrogen sulfide

    International Nuclear Information System (INIS)

    Sequential exposures of trimethylaluminum and hydrogen sulfide are used to deposit aluminum sulfide thin films by atomic layer deposition (ALD) in the temperature ranging from 100 to 200 °C. Growth rate of 1.3 Å per ALD cycle is achieved by in-situ quartz crystal microbalance measurements. It is found that the growth rate per ALD cycle is highly dependent on the purging time between the two precursors. Increased purge time results in higher growth rate. Surface limited chemistry during each ALD half cycle is studied by in-situ Fourier transformed infrared vibration spectroscopy. Time of flight secondary ion-mass spectroscopy measurement is used to confirm elemental composition of the deposited films

  18. Sulfide Catalysts Supported on Porous Aromatic Frameworks for Naphthalene Hydroprocessing

    Directory of Open Access Journals (Sweden)

    Eduard Karakhanov

    2016-08-01

    Full Text Available This paper describes the first example of using porous aromatic frameworks as supports for sulfide catalysts for the hydrogenation of aromatic hydrocarbons. The synthesis of bimetallic Ni-W and Ni-Mo sulfides was performed by in situ decomposition of [(n-Bu4N]2[Ni(MeS42] (Me = W, Mo complexes, supported on mesoporous aromatic framework with a diamond-like structure. It is shown that the highest naphthalene conversions were achieved in the case of additional sulfidation with sulfur. After the reaction, catalysts were characterized by X-ray photoelectron spectroscopy and high-resolution transmission electron microscopy. The activity of synthesized catalysts has been studied using naphthalene as a model substrate. The materials used in this study were substantially active in hydrogenation and slightly in hydrocracking of naphthalene.

  19. Extraction of Nanosized Cobalt Sulfide from Spent Hydrocracking Catalyst

    Directory of Open Access Journals (Sweden)

    Samia A. Kosa

    2013-01-01

    Full Text Available The processes used for the extraction of metals (Co, Mo, and Al from spent hydrotreating catalysts were investigated in this study. A detailed mechanism of the metal extraction process is described. Additionally, a simulation study was performed to understand the sulfidizing mechanism. The suggested separation procedure was effective and achieved an extraction of approximately 80–90%. In addition, the sulfidization mechanism was identified. This sulfidizing process for Co was found to involve an intermediate, the structure of which was proposed. This proposed intermediate was confirmed through simulations. Moreover, the activities of the spent and the regenerated catalyst were examined in the cracking of toluene. The modification of the spent catalyst through the use of different iron oxide loadings improved the catalytic activity.

  20. Substrate and stereocontrolled iodocycloetherification of highly functionalized enantiomerically pure allylic alcohols: application to synthesis of cytotoxic 2-epi jaspine B and its biological evaluation.

    Science.gov (United States)

    Kundooru, Somireddy; Das, Pintu; Meena, Sanjeev; Kumar, Vikash; Siddiqi, Mohammad Imran; Datta, Dipak; Shaw, Arun K

    2015-08-14

    Stereoselectivities of electrophilic additions of molecular iodine to enantiomerically pure highly functionalized allylic alcohols with internal nucleophiles have been investigated. The intramolecular nucleophilic attack on the I2-π complex by an oxygen nucleophile to obtain tri- and tetrasubstituted THFs is highly regio-, stereoselective and substrate controlled. The application of this study has been shown by utilizing one of the THFs 4a as a key intermediate to complete the total synthesis of marine anti-cancer natural product 2-epi jaspine B. PMID:26133669

  1. Proton conductive membranes based on poly (styrene-co-allyl alcohol semi-IPN

    Directory of Open Access Journals (Sweden)

    Felipe Augusto Moro Loureiro

    2014-01-01

    Full Text Available The optimization of fuel cell materials, particularly polymer membranes, for PEMFC has driven the development of methods and alternatives to achieve systems with more adequate properties to this application. The sulfonation of poly (styrene-co-allyl alcohol (PSAA, using sulfonating agent:styrene ratios of 2:1, 1:1, 1:2, 1:4, 1:6, 1:8 and 1:10, was previously performed to obtain proton conductive polymer membranes. Most of those membranes exhibited solubility in water with increasing temperature and showed conductivity of approximately 10-5 S cm-1. In order to optimize the PSAA properties, especially decreasing its solubility, semi-IPN (SIPN membranes are proposed in the present study. These membranes were obtained from the diglycidyl ether of bisphenol A (DGEBA, curing reactions in presence of DDS (4,4-diaminodiphenyl sulfone and PSAA. Different DGEBA/PSAA weight ratios were employed, varying the PSAA concentration between 9 and 50% and keeping the mass ratio of DGEBA:DDS as 1:1. The samples were characterized by FTIR and by electrochemical impedance spectroscopy. Unperturbed bands of PSAA were observed in the FTIR spectra of membranes, suggesting that chemical integrity of the polymer is maintained during the synthesis. In particular, bands involving C-C stretching (1450 cm-1, C=C (aromatic, ~ 3030 cm-1 and C-H (2818 and 2928 cm-1 were observed, unchanged after the synthesis. The disappearance or reduction of the intensity of the band at 916 cm-1, attributed to the DGEBA epoxy ring, is evidenced for all samples, indicating the epoxy ring opening and the DGEBA crosslinking. Conductivity of H3PO4 doped membranes increases with temperature, reaching 10-4 S cm-1.

  2. S-Allyl-Cysteines Reduce Amelioration of Aluminum Induced Toxicity in Rats

    Directory of Open Access Journals (Sweden)

    Sadhana Shrivastava

    2011-01-01

    Full Text Available Problem statement: Aluminum (Al is a trivalent cation found in its ionic form in most kinds of animal tissues and in natural waters everywhere. Approach: It is a potent neurotoxin and has been associated in the pathogenesis of several clinical disorders including Alzheimer’s disease. Results: The aim of the study was to demonstrate the protective effect of S-Allyl-Cysteines (SAC against Al-induced toxicity in rat model on certain biochemical parameters, lipid peroxidation and oxidative stress enzymes of white albino rats. Six rats per group were divided into various treatment groups. Group one rats were given normal saline and served as control group. Group two animals received Al as aluminum nitrate 32.5 mg (i.p. for the induction of toxicity. Group three to five received different doses of SAC (25, 50 and 100 mg kg-1 for 3 days after 24 h of Al toxicity. Rats were orally administered their respective doses every day for 3 days. Evaluations were made in blood and tissues. The activity of Acetylcholinesterase (AchE was inhibited in all the parts of brain after Al intoxication. Significant rise were observed the Activities of Serum Transaminases (AST and ALT after toxicant exposure. The activity of â-Aminolevulinic acid Dehydratase (ALAD in blood and â-Aminolevulinic Acid Synthetase (ALAS in brain was decreased after Al exposure. Al significant increased cholesterol, triglyceride, creatinine and urea level in serum. TBARS level was significantly higher and GSH content were significantly lower during toxicity. Total and esterified cholesterol in liver, kidney and brain were increased after Al exposure. Histopathological changes in liver, kidney and brain were also recouped with the therapy. Conclusion/Recommendations: Our data proved that SAC which is a bioactive and bioavailable component of garlic has organosulfur compounds which regulates the thiol status of the cell and scavenges free radicals and work as an antioxidant. Thus SAC

  3. Vibronic spectra of the allyl radical at 6-8 eV with resonance-enhanced multiphoton ionization technique

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The allyl radical was produced in molecular beam by pyrolysis of allyl iodide. The vibronic spectra from ground state to six new electronic states of the allyl radical at 6-8 eV, p?3dxz , p?3dxy, and p?ns (n=4, 6, 7, 8) were observed firstly with the aid of time-of-flight mass spectroscopy and resonance-enhanced multiphoton ionization technique. Vibrational progression of n7 (C3 bend) with gross spacing of about 430 cm-1 was observed in ns Rydberg states. The adiabatic ionization potential of the allyl radical was obtained to be (65641 ± 20) cm-1 ((8.138 ± 0.002) eV) by fitting the term values of ns (n=4,6,7,8) Rydberg states with Rydberg formula.

  4. Sulfide mineralization in ultramafic rocks of the Faryab ophiolite complex, southern Kerman

    Directory of Open Access Journals (Sweden)

    Mohammad Ali Rajabzadeh

    2015-10-01

    Full Text Available Introduction Worldwide, Ni-Cu and PGE magmatic sulfide deposits are confined to the lower parts of stratiform mafic and ultramafic complexes. However, ophiolite mafic and ultramafic complexes have been rarely explored for sulfide deposits despite the fact that they have been extensively explored and exploited for chromite. Sulfide saturation during magmatic evolution is necessary for sulfide mineralization, in which sulfide melts scavenge chalcophile metals from the parent magma and concentrate them in specific lithological zones. The lack of exploration for sulfides in this environment suggests that sulfide saturation is rarely attained in ophiolite-related magmas. Some ophiolites, however, contain sulfide deposits, such as at Acoje in Philippines, and Cliffs in Shetland, U.K. (Evans, 2000; Naldrett, 2004. The Faryab ophiolite complex in southern Kerman Province, the most important mining area for chromite deposits in Iran, is located in the southwest part of the Makran Zone. Evidence of sulfide mineralization has been reported there by some authors (e.g. Rajabzadeh and Moosavinasab, 2013. This paper discusses the genesis of sulfides in the Faryab ophiolite using mineral chemistry of the major mineral phases in different rocks of the ophiolite column in order to determine the possible lithological location of sulfide deposits. Materials and methods Seventy three rock samples from cumulate units were collected from surficial occurrences and drill core. The samples were studied using conventional microscopic methods and the mineralogy confirmed by x-ray diffraction. Electron microprobe analysis was carried out on different mineral phases in order to determine the chemistry of the minerals used in the interpretation of magma evolution in the Faryab ophiolite. Lithologically, the Faryab ophiolite complex is divided into two major parts: the northern part includes magmatic rocks and the southern part is comprised of rocks residual after partial

  5. Mechanism of sulfide effect on viscosity of HPAM polymer solution

    Institute of Scientific and Technical Information of China (English)

    康万利; 周阳; 王志伟; 孟令伟; 刘述忍; 白宝君

    2008-01-01

    The effect of sulfide on HPAM solution viscosity was studied using BROOKFIELD DV-II viscometer,and the interaction mechanism was discussed.The HPAM solution viscosity was investigated through fully reducing sulfide by the addition of hydrogen peroxide oxidation,and the mechanism of increasing polymer viscosity was investigated.The experimental results also show that there is a critical concentration of 15 mg/L.Below it,the loss rate of HPAM solution viscosity increases more rapidly,but becomes slowly above the critical concentration.A theoretical guidance for oilfields to prepare polymer solution using sewage-water by eliminating sulfide,and it is also importance to prepare polymer solution using sewage-water and save fresh water.

  6. Confirming the existence of π-allyl-palladium intermediates during the reaction of meta photocycloadducts with palladium(ii) compounds

    OpenAIRE

    Penkett, Clive S; Brann, Paul J; Woolford, Jason A.; Kahan, Rachel J

    2013-01-01

    The transient existence of π-allyl-palladium intermediates formed by the reaction of Pd(OAc)2 and anisole-derived meta photocycloadducts has been demonstrated using NMR techniques. The intermediates tended to be short-lived and underwent rapid reductive elimination of palladium metal to form allylic acetates, however this degradation process could be delayed by changing the reaction solvent from acetonitrile to chloroform.

  7. Enantioselective Allylic C-H Oxidation of Terminal Olefins to Isochromans by Palladium(II)/Chiral Sulfoxide Catalysis.

    Science.gov (United States)

    Ammann, Stephen E; Liu, Wei; White, M Christina

    2016-08-01

    The enantioselective synthesis of isochroman motifs has been accomplished by palladium(II)-catalyzed allylic C-H oxidation from terminal olefin precursors. Critical to the success of this goal was the development and utilization of a novel chiral aryl sulfoxide-oxazoline (ArSOX) ligand. The allylic C-H oxidation reaction proceeds with the broadest scope and highest levels of asymmetric induction reported to date (avg. 92 % ee, 13 examples with greater than 90 % ee). PMID:27376625

  8. Growth kinetics of hydrogen sulfide oxidizing bacteria in corroded concrete from sewers

    International Nuclear Information System (INIS)

    Hydrogen sulfide oxidation by microbes present on concrete surfaces of sewer pipes is a key process in sewer corrosion. The growth of aerobic sulfur oxidizing bacteria from corroded concrete surfaces was studied in a batch reactor. Samples of corrosion products, containing sulfur oxidizing bacteria, were suspended in aqueous solution at pH similar to that of corroded concrete. Hydrogen sulfide was supplied to the reactor to provide the source of reduced sulfur. The removal of hydrogen sulfide and oxygen was monitored. The utilization rates of both hydrogen sulfide and oxygen suggested exponential bacterial growth with median growth rates of 1.25 d-1 and 1.33 d-1 as determined from the utilization rates of hydrogen sulfide and oxygen, respectively. Elemental sulfur was found to be the immediate product of the hydrogen sulfide oxidation. When exponential growth had been achieved, the addition of hydrogen sulfide was terminated leading to elemental sulfur oxidation. The ratio of consumed sulfur to consumed oxygen suggested that sulfuric acid was the ultimate oxidation product. To the knowledge of the authors, this is the first study to determine the growth rate of bacteria involved in concrete corrosion with hydrogen sulfide as source of reduced sulfur.

  9. What do we really know about the role of microorganisms in iron sulfide mineral formation?

    Science.gov (United States)

    Picard, Aude; Gartman, Amy; Girguis, Peter

    2016-06-01

    Iron sulfide mineralization in low-temperature systems is a result of biotic and abiotic processes, though the delineation between these two modes of formation is not always straightforward. Here we review the role of microorganisms in the precipitation of extracellular iron sulfide minerals. We summarize the evidence that links sulfur-metabolizing microorganisms and sulfide minerals in nature and we present a critical overview of laboratory-based studies of the nucleation and growth of iron sulfide minerals in microbial cultures. We discuss whether biologically derived minerals are distinguishable from abiotic minerals, possessing attributes that are uniquely diagnostic of biomineralization. These inquiries have revealed the need for additional thorough, mechanistic and high-resolution studies to understand microbially mediated formation of a variety of sulfide minerals across a range of natural environments.

  10. New Findings in Hydrogen Sulfide Related Corrosion of Concrete Sewers

    DEFF Research Database (Denmark)

    Nielsen, Asbjørn Haaning; Jensen, Henriette Stokbro; Hvitved-Jacobsen, Thorkild;

    2009-01-01

    This paper summarizes major findings of a long-term study of hydrogen sulfide gas (H2S) adsorption and oxidation on concrete and plastic sewer pipe surfaces. The processes have been studied using a pilot-scale setup designed to replicate conditions in a gravity sewer located downstream of a force...

  11. Application of Borehole SIP Technique to Sulfide Mineral Exploration

    Science.gov (United States)

    Kim, Changryol; Park, Mi Kyung; Park, Samgyu; Sung, Nak Hoon; Shin, Seung Wook

    2016-04-01

    In the study, SIP (Spectral Induced Polarization) well logging probe system was developed to rapidly locate the metal ore bodies with sulfide minerals in the boreholes. The newly developed SIP logging probe employed the non-polarizable electrodes, consisting of zinc chloride (ZnCl2), sodium chloride (NaCl), gypsum (CaSO4·2H2O), and water (H2O), instead of existing copper electrodes, leading to eliminating the EM coupling effect in the IP surveys as much as possible. In addition, the SIP logging system is designed to make measurements down to maximum 500 meters in depth in the boreholes. The SIP well logging was conducted to examine the applicability of the SIP probe system to the boreholes at the ore mine in Jecheon area, Korea. The boreholes used in the SIP logging are known to have penetrated the metal ore bodies with sulfide minerals from the drilling investigations. The ore mine of the study area is the scarn deposits surrounded by the limestone or lime-silicate rocks in Ordovician period. The results of the SIP well logging have shown that the borehole segments with limestone or lime-silicate rocks yielded the insignificant SIP responses while the borehole segments with sulfide minerals (e.g. pyrite) provided the significant phase shifts of the SIP responses. The borehole segments penetrating the metal ore body, so-called cupola, have shown very high response of the phase shift, due to the high contents of the sulfide mineral pyrite. The phase shifts of the SIP response could be used to estimate the grade of the ore bodies since the higher contents of the sulfide minerals, the higher magnitudes of the phase shifts in the SIP responses. It is, therefore, believed that the borehole SIP technique can be applied to investigate the metal ore bodies with sulfide minerals, and that could be used to estimate the ore grades as a supplementary tool in the future.

  12. Redox Biochemistry of Hydrogen Sulfide*

    OpenAIRE

    Kabil, Omer; Banerjee, Ruma

    2010-01-01

    H2S, the most recently discovered gasotransmitter, might in fact be the evolutionary matriarch of this family, being both ancient and highly reduced. Disruption of γ-cystathionase in mice leads to cardiovascular dysfunction and marked hypertension, suggesting a key role for this enzyme in H2S production in the vasculature. However, patients with inherited deficiency in γ-cystathionase apparently do not present vascular pathology. A mitochondrial pathway disposes sulfide and couples it to oxid...

  13. The solubility of iron sulfides and their role in mass transport in Girdler-Sulfide heavy water plants

    International Nuclear Information System (INIS)

    The solubilities of several iron sulfides, mackinawite FeSsub((1-x)), troilite FeS, pyrrhotite Fesub((1-x))S (monoclinic and hexagonal), and pyrite FeS2 have been determined in aqueous H2S solution at 0.1 MPa and 1.8 MPa H2S pressures between 25 deg and 125 deg C. The dependence of solubility on the pH of the medium has also been studied. It is concluded that since mackinawite is the most soluble of the iron sulfides, and has the highest dissolution rate and the steepest decline in solubility with temperature, its prolonged formation during plant operation should be avoided to minimize iron transport from lower to higher temperature areas in Girdler-Sulfide (G.S.) heavy water plants. This can be achieved by a preconditioning of carbon steel surfaces to convert mackinawite to pyrrhotite and pyrite

  14. First detection of doubly deuterated hydrogen sulfide

    CERN Document Server

    Vastel, C; Ceccarelli, C; Pearson, J

    2003-01-01

    This work was carried out with using the Caltech Submillimeter Observatory and presents the observational study of HDS and D2S towards a sample of Class 0 sources, and dense cores. We report the first detection of doubly deuterated hydrogen sulfide (D2S) in two dense cores and analyze the chemistry of these molecules aiming to help understand the deuteration processes in the interstellar medium. The observed values of the D2S/HDS ratio, and upper limits, require an atomic D/H ratio in the accreting gas of 0.1-1. The study presented in this Letter supports the hypothesis that formaldehyde, methanol and hydrogen sulfide are formed on the grain surfaces, during the cold pre-stellar core phase, where the CO depleted gas has large atomic D/H ratios. The high values for the D/H ratios are consistent with the predictions of a recent gas-phase chemical model that includes H3+ and its deuterated isotopomers, H2D+, D2H+ and D3+ (Roberts et al. 2003).

  15. Crystal structure of (E-3-allyl-2-sulfanylidene-5-[(thiophen-2-ylmethylidene]thiazolidin-4-one

    Directory of Open Access Journals (Sweden)

    Rahhal El Ajlaoui

    2015-06-01

    Full Text Available Molecules of the title compound, C11H9NOS3, are built up by one thiophene and one 2-thioxathiazolidin-4-one ring which are connected by a methylene bridge. In addition, there is an allyl substituent attached to nitrogen. The two rings are almost coplanar, making a dihedral angle between them of 0.76 (11°. The allyl group is oriented perpendicular to the mean plane through both ring systems. The crystal structure exhibits inversion dimers in which molecules are linked by pairs of C—H...O hydrogen bonds. Additional π–π interactions between neighboring thiophene and 2-thioxathiazolidin-4-one rings [intercentroid distance = 3.694 (2 Å] lead to the formation of a three-dimensional network.

  16. Rheology and viscosity scaling of gelatin/1-allyl-3-methylimidazolium chloride solution

    Science.gov (United States)

    Qiao, Congde; Li, Tianduo; Zhang, Ling; Yang, Xiaodeng; Xu, Jing

    2014-05-01

    Gelatin/1-allyl-3-methylimidazolium chloride solutions are prepared by using the ionic liquid 1-allyl-3-methylimidazolium chloride as solvent. The rheological properties of the gelatin solutions have been investigated by steady shear and oscillatory shear measurements. In the steady shear measurements, the gelatin solutions with high concentration show a shear-thinning flow behavior at high shear rates, while another shear thinning region can be found in the dilute gelatin solutions at low shear rates. The overlap concentration of gelatin in [amim]Cl is 1.0 wt% and the entanglement concentration is a factor of 4 larger (4.0 wt%). The high intrinsic viscosity (295 mL/g) indicates that the gelatin chains dispersed freely in the ionic liquid and no aggregation phenomenon occurs in dilute gelatin solution. The frequency dependences of modulus changed obviously with an increase in gelatin concentration. The empirical time-temperature superposition principle holds true at the experimental temperatures.

  17. Hydrogen evolution from water through metal sulfide reactions

    International Nuclear Information System (INIS)

    Transition metal sulfides play an important catalytic role in many chemical reactions. In this work, we have conducted a careful computational study of the structures, electronic states, and reactivity of metal sulfide cluster anions M2SX− (M = Mo and W, X = 4–6) using density functional theory. Detailed structural analysis shows that these metal sulfide anions have ground state isomers with two bridging sulfide bonds, notably different in some cases from the corresponding oxides with the same stoichiometry. The chemical reactivity of these metal sulfide anions with water has also been carried out. After a thorough search on the reactive potential energy surface, we propose several competitive, energetically favorable, reaction pathways that lead to the evolution of hydrogen. Selectivity in the initial water addition and subsequent hydrogen migration are found to be the key steps in all the proposed reaction channels. Initial adsorption of water is most favored involving a terminal metal sulfur bond in Mo2S4− isomers whereas the most preferred orientation for water addition involves a bridging metal sulfur bond in the case of W2S4− and M2S5− isomers. In all the lowest energy H2 elimination steps, the interacting hydrogen atoms involve a metal hydride and a metal hydroxide (or thiol) group. We have also observed a higher energy reaction channel where the interacting hydrogen atoms in the H2 elimination step involve a thiol (–SH) and a hydroxyl (–OH) group. For all the reaction pathways, the Mo sulfide reactions involve a higher barrier than the corresponding W analogues. We observe for both metals that reactions of M2S4− and M2S5− clusters with water to liberate H2 are exothermic and involve modest free energy barriers. However, the reaction of water with M2S6− is highly endothermic with a considerable barrier due to saturation of the local bonding environment

  18. Non-hydrolytic Sol-gel Synthesis of Tin Sulfides

    Science.gov (United States)

    Kaur, Rajvinder

    systematic study was carried out to understand the influence of all reaction variables, which include tin halides, thioethers, solvents, time, temperature, stoichiometry and concentration. Fine tuning of all reaction variables was carried out. The crystallization and phase stability of the as-recovered products was further studied by heat treatments of the samples. A detailed investigation of synthetic variables during NHSG reactions resulted in controlled synthesis of two crystalline tin sulfide polymorphs, SnS and SnS2. A third polymorph, Sn2S3, could be obtained after heat treatments in the temperature range of 400 to 500 °C. Conditions for the targeted synthesis of particles with various sizes and morphologies were established. Samples were characterized by powder X-ray diffraction, electron microscopy in combination with EDS, CHNS analysis and thermo gravimetric/differential thermal analysis.

  19. Hydrogen sulfide intervention in focal cerebral ischemia/reperfusion injury in rats

    Directory of Open Access Journals (Sweden)

    Xin-juan Li

    2015-01-01

    Full Text Available The present study aimed to explore the mechanism underlying the protective effects of hydrogen sulfide against neuronal damage caused by cerebral ischemia/reperfusion. We established the middle cerebral artery occlusion model in rats via the suture method. Ten minutes after middle cerebral artery occlusion, the animals were intraperitoneally injected with hydrogen sulfide donor compound sodium hydrosulfide. Immunofluorescence revealed that the immunoreactivity of P2X 7 in the cerebral cortex and hippocampal CA1 region in rats with cerebral ischemia/reperfusion injury decreased with hydrogen sulfide treatment. Furthermore, treatment of these rats with hydrogen sulfide significantly lowered mortality, the Longa neurological deficit scores, and infarct volume. These results indicate that hydrogen sulfide may be protective in rats with local cerebral ischemia/reperfusion injury by down-regulating the expression of P2X 7 receptors.

  20. Nano Transition Metal Sulfide Catalyst for Solvolysis Liquefaction of Soda Lignin

    International Nuclear Information System (INIS)

    Solvolysis liquefaction of soda lignin in the presence of various transition metal sulfide catalysts was studied to investigate the catalyst effects on the oil and gas yields, conversion rate and higher heating value (HHV) of oil. Nano sized copper sulfide, iron sulfide and molybdenum sulfide were successfully synthesized via a simple hydrothermal method under reaction temperature 200 degree Celsius for 90 min. The addition of transition metal sulfide based catalysts (CuS, MoS2 and FeS2) enhanced both production of the oils and gas and the higher heating value (HHV) of oil products. A high oil and gas yields of 82.1 % and 2890 cm3 was obtained with MoS2 at 250 degree Celsius for 60 min. Elemental analyses for the oils revealed that the liquid products have much higher heating values than the crude soda lignin powder. (author)

  1. Synthesis of rare earth sulfides and their UV-vis absorption spectra

    Institute of Scientific and Technical Information of China (English)

    YUAN Haibin; ZHANG Jianhui; YU Ruijin; SU Qiang

    2009-01-01

    Rare earth sulfides were systematically synthesized via the sulfurization of their commercial oxide powders using CS2 gas to shorten sulfurization time, and their UV-vis absorption spectra were investigated. The appropriate sulfurization conditions were studied. For the rare earth sulfides with the same crystal structure, the sulfurization temperature showed increasing tendency with the decrease of rare earth element atomic radii. The UV-vis absorption spectra of rare earth sulfides did not depend on the crystal structure of rare earth sulfides, but on the 4f electronic structure of rare earth element. The data showed that the optical band gaps of rare earth sulfides were irregular, and the values ranged from 1.65 to 3.75 eV.

  2. Sulfide intrusion in seagrasses assessed by stable sulfur isotopes—a synthesis of current results

    DEFF Research Database (Denmark)

    Holmer, Marianne; Hasler-Sheetal, Harald

    2014-01-01

    Sulfide intrusion in seagrasses, as assessed by stable sulfur isotope signals, is widespread in all climate zones, where seagrasses are growing. Seagrasses can incorporate substantial amounts of 34S-depleted sulfide into their tissues with up to 87% of the total sulfur in leaves derived from...... sedimentary sulfide. Correlations between δ34S in leaves, rhizomes, and roots show that sedimentary sulfide is entering through the roots, either in the form of sulfide or sulfate, and translocated to the rhizomes and the leaves. The total sulfur content of the seagrasses increases as the proportion of...... sulfur in the tissue, and other sulfur containing compounds such as thiols, organic sulfur, and sulfate contribute to the accumulated sulfur pool. Experimental studies with seagrasses exposed to environmental and biological stressors show decreasing δ34S in the tissues along with reduction in growth...

  3. Allyl isothiocyanate induced stress response in Caenorhabditis elegans

    OpenAIRE

    Saini AkalRachna K; Tyler Robert T; Shim Youn; Reaney Martin JT

    2011-01-01

    Abstract Background Allyl isothiocyanate (AITC) from mustard is cytotoxic; however the mechanism of its toxicity is unknown. We examined the effects of AITC on heat shock protein (HSP) 70 expression in Caenorhabditis elegans. We also examined factors affecting the production of AITC from its precursor, sinigrin, a glucosinolate, in ground Brassica juncea cv. Vulcan seed as mustard has some potential as a biopesticide. Findings An assay to determine the concentration of AITC in ground mustard ...

  4. Iron(III) chloride catalyzed glycosylation of peracylated sugars with allyl/alkynyl alcohols

    Energy Technology Data Exchange (ETDEWEB)

    Narayanaperumal, Senthil; Silva, Rodrigo Cesar da; Monteiro, Julia L.; Correa, Arlene G.; Paixao, Marcio W., E-mail: mwpaixao@ufscar.br [Universidade Federal de Sao Carlos (UFSCAR), SP (Brazil). Dept. de Quimica

    2012-11-15

    In this work, the use of ferric chloride as an efficient catalyst in glycosylation reactions of sugars in the presence of allyl and alkynyl alcohols is described. The corresponding glycosides were obtained with moderate to good yields. This new procedure presented greater selectivity when compared to classic methods found in the literature. Principal features of this simple method include non-hazardous reaction conditions, low-catalyst loading, good yields and high anomeric selectivity (author)

  5. Lewis base catalyzed enantioselective allylic hydroxylation of Morita-Baylis-Hillman carbonates with water

    KAUST Repository

    Zhu, Bo

    2011-08-19

    A Lewis base catalyzed allylic hydroxylation of Morita-Baylis-Hillman (MBH) carbonates has been developed. Various chiral MBH alcohols can be synthesized in high yields (up to 99%) and excellent enantioselectivities (up to 94% ee). This is the first report using water as a nucleophile in asymmetric organocatalysis. The nucleophilic role of water has been verified using 18O-labeling experiments. © 2011 American Chemical Society.

  6. Iron(III) chloride catalyzed glycosylation of peracylated sugars with allyl/alkynyl alcohols

    International Nuclear Information System (INIS)

    In this work, the use of ferric chloride as an efficient catalyst in glycosylation reactions of sugars in the presence of allyl and alkynyl alcohols is described. The corresponding glycosides were obtained with moderate to good yields. This new procedure presented greater selectivity when compared to classic methods found in the literature. Principal features of this simple method include non-hazardous reaction conditions, low-catalyst loading, good yields and high anomeric selectivity (author)

  7. Photochemical Synthesis and Versatile Functionalization Method of a Robust Porous Poly(ethylene glycol methacrylate-co-allyl methacrylate) Monolith Dedicated to Radiochemical Separation in a Centrifugal Microfluidic Platform

    OpenAIRE

    Marion Losno; Ivan Ferrante; René Brennetot; Jérôme Varlet; Cécile Blanc; Bernard Grenut; Etienne Amblard; Stéphanie Descroix; Clarisse Mariet

    2016-01-01

    The use of a centrifugal microfluidic platform is an alternative to classical chromatographic procedures for radiochemistry. An ion-exchange support with respect to the in situ light-addressable process of elaboration is specifically designed to be incorporated as a radiochemical sample preparation module in centrifugal microsystem devices. This paper presents a systematic study of the synthesis of the polymeric porous monolith poly(ethylene glycol methacrylate-co-allyl methacrylate) used as ...

  8. Rhodium-catalysed asymmetric allylic arylation of racemic halides with arylboronic acids

    Science.gov (United States)

    Sidera, Mireia; Fletcher, Stephen P.

    2015-11-01

    Csp2-Csp2 cross-coupling reactions between arylboronic acid and aryl halides are widely used in both academia and industry and are strategically important in the development of new agrochemicals and pharmaceuticals. Csp2-Csp3 cross-coupling reactions have been developed, but enantioselective variations are rare and simply retaining the stereochemistry is a problem. Here we report a highly enantioselective Csp2-Csp3 bond-forming method that couples arylboronic acids to racemic allyl chlorides. Both enantiomers of a cyclic chloride are converted into a single enantiomer of product via a dynamic kinetic asymmetric transformation. This Rh-catalysed method uses readily available and inexpensive building blocks and is mild and broadly applicable. For electron-deficient, electron-rich or ortho-substituted boronic acids better results are obtained with racemic allyl bromides. Oxygen substitution in the allyl halide is tolerated and the products can be functionalized to provide diverse building blocks. The approach fills a significant gap in the methods for catalytic asymmetric synthesis.

  9. Nouvelles Réactions d'Allylation Radicalaire : Exploitation de la Rupture homolytique de Liaisons Carbone-Oxygène et Carbone-Carbone

    OpenAIRE

    Debien, Laurent

    2013-01-01

    This PhD thesis is divided in eight chapters. The first three bibliographic chapters present the general principles of radical chemistry, the possibility offered by the xanthate radical chemistry and a review of the radical allylation methods, main focus of this work. The three next chapters are dedicated to the exploitation of the radical allylation of allylic alcohols, recently discovered in our laboratory. The use of such a technology enabled the preparation of functionalized enol ethers, ...

  10. Experimental constraints on gold and silver solubility in iron sulfides

    Energy Technology Data Exchange (ETDEWEB)

    Pal' yanova, Galina [Institute of Geology and Mineralogy, Siberian Branch of the Russian Academy of Sciences, 3, Koptyuga, Novosibirsk, 630090 (Russian Federation); Novosibirsk State University, Russia, 2, Pirogova, Novosibirsk, 630090 (Russian Federation); Mikhlin, Yuri [Institute of Chemistry and Chemical Technology, Siberian Branch of the Russian Academy of Sciences, Akademgorodok, 50/24, Krasnoyarsk, 660036 (Russian Federation); Kokh, Konstantin, E-mail: k.a.kokh@gmail.com [Institute of Geology and Mineralogy, Siberian Branch of the Russian Academy of Sciences, 3, Koptyuga, Novosibirsk, 630090 (Russian Federation); Novosibirsk State University, Russia, 2, Pirogova, Novosibirsk, 630090 (Russian Federation); Siberian Physical–Technical Institute of Tomsk State University, 1, Novosobornaya, Tomsk, 634050 (Russian Federation); Karmanov, Nick [Institute of Geology and Mineralogy, Siberian Branch of the Russian Academy of Sciences, 3, Koptyuga, Novosibirsk, 630090 (Russian Federation); Seryotkin, Yurii [Institute of Geology and Mineralogy, Siberian Branch of the Russian Academy of Sciences, 3, Koptyuga, Novosibirsk, 630090 (Russian Federation); Novosibirsk State University, Russia, 2, Pirogova, Novosibirsk, 630090 (Russian Federation)

    2015-11-15

    Experiments were performed to determine crystallization of Fe,S-melts (pyriti≿ and troilitic with molar ratio S/Fe ratios of 2 and 1, respectively) containing traces of gold and silver at (Ag/Au){sub wt} ratios varying from 10 to 0.1. The solid products were studied by optical microscopy, scanning electron microscopy, X-ray powder diffraction (XRD), microprobe analysis, and X-ray photoelectron spectroscopy (XPS) in order to reveal the concentration limits of “invisible” gold and silver in magmatic iron sulfides, and to determine the influence of sulfur on forms of precious metals in the Fe–S system with different Ag/Au ratios. Au–Ag phases do not form inclusions but instead concentrate on the grain boundaries in the synthetic pyrrhotite and troilite, while pyrite comprises micro- (1–5 μm) and macroinclusions of Au–Ag alloys and Au–Ag sulfides. In “pyriti≿” systems, the fineness of alloys increases from 650 to 970‰ and the composition of sulfides changes from acanthite (Ag{sub 2}S) to uytenbogaardtite (Ag{sub 3}AuS{sub 2}) and petrovskaite (AgAuS) as the Ag/Au ratio decreases. The concentrations of “invisible” precious metals revealed in troilite were 0.040 ± 0.013 wt.% Au and 0.079 ± 0.016 wt.% Ag. Measured concentrations in pyrite and pyrrhotite were <0.024 wt.% Au and <0.030 wt.% Ag. The surface layers of iron sulfides probed with XPS were enriched in the precious metals, and in silver relative to gold, especially in the systems with Fe/S = 1, probably, due to depletion of the metallic alloy surfaces with gold. Au- and Ag-bearing iron sulfides crystallized primarily from melts may be the source of redeposited phases in hydrothermal and hypergene processes. - Highlights: • The samples of Fe–S–Au–Ag system were synthesized. • Coupled solubility of gold and silver in iron sulfides was specified. • Ag–Au inclusions on surfaces of iron sulfides are likely to be enriched in silver. • Au–Ag sulfides can exist along with

  11. Experimental constraints on gold and silver solubility in iron sulfides

    International Nuclear Information System (INIS)

    Experiments were performed to determine crystallization of Fe,S-melts (pyriti≿ and troilitic with molar ratio S/Fe ratios of 2 and 1, respectively) containing traces of gold and silver at (Ag/Au)wt ratios varying from 10 to 0.1. The solid products were studied by optical microscopy, scanning electron microscopy, X-ray powder diffraction (XRD), microprobe analysis, and X-ray photoelectron spectroscopy (XPS) in order to reveal the concentration limits of “invisible” gold and silver in magmatic iron sulfides, and to determine the influence of sulfur on forms of precious metals in the Fe–S system with different Ag/Au ratios. Au–Ag phases do not form inclusions but instead concentrate on the grain boundaries in the synthetic pyrrhotite and troilite, while pyrite comprises micro- (1–5 μm) and macroinclusions of Au–Ag alloys and Au–Ag sulfides. In “pyriti≿” systems, the fineness of alloys increases from 650 to 970‰ and the composition of sulfides changes from acanthite (Ag2S) to uytenbogaardtite (Ag3AuS2) and petrovskaite (AgAuS) as the Ag/Au ratio decreases. The concentrations of “invisible” precious metals revealed in troilite were 0.040 ± 0.013 wt.% Au and 0.079 ± 0.016 wt.% Ag. Measured concentrations in pyrite and pyrrhotite were <0.024 wt.% Au and <0.030 wt.% Ag. The surface layers of iron sulfides probed with XPS were enriched in the precious metals, and in silver relative to gold, especially in the systems with Fe/S = 1, probably, due to depletion of the metallic alloy surfaces with gold. Au- and Ag-bearing iron sulfides crystallized primarily from melts may be the source of redeposited phases in hydrothermal and hypergene processes. - Highlights: • The samples of Fe–S–Au–Ag system were synthesized. • Coupled solubility of gold and silver in iron sulfides was specified. • Ag–Au inclusions on surfaces of iron sulfides are likely to be enriched in silver. • Au–Ag sulfides can exist along with native gold in pyrite

  12. H2S exposure elicits differential expression of candidate genes in fish adapted to sulfidic and non-sulfidic environments.

    Science.gov (United States)

    Tobler, Michael; Henpita, Chathurika; Bassett, Brandon; Kelley, Joanna L; Shaw, Jennifer H

    2014-09-01

    Disentangling the effects of plasticity, genetic variation, and their interactions on organismal responses to environmental stressors is a key objective in ecological physiology. We quantified the expression of five candidate genes in response to hydrogen sulfide (H2S) exposure in fish (Poecilia mexicana, Poeciliidae) from a naturally sulfide-rich environment as well as an ancestral, non-sulfidic population to test for constitutive and environmentally dependent population differences in gene expression patterns. Common garden raised individuals that had never encountered environmental H2S during their lifetime were subjected to short or long term H2S exposure treatments or respective non-sulfidic controls. The expression of genes involved in responses to H2S toxicity (cytochrome c oxidase, vascular endothelial growth factor, and cytochrome P450-2J6), H2S detoxification (sulfide:quinone oxidoreductase), and endogenous H2S production (cystathionine γ lyase) was determined in both gill and liver tissues by real time PCR. The results indicated complex changes in expression patterns that--depending on the gene--not only differed between organs and populations, but also on the type of H2S exposure. Populations differences, both constitutive and H2S exposure dependent (i.e., plastic), in gene expression were particularly evident for sulfide:quinone oxidoreductase, vascular endothelial growth factor, and to a lesser degree for cytochrome P450-2J6. Our study uncovered putatively adaptive modifications in gene regulation that parallel previously documented adaptive changes in phenotypic traits. PMID:24813672

  13. On the Nature of the Intermediates and the Role of Chloride Ions in Pd-Catalyzed Allylic Alkylations: Added Insight from Density Functional Theory

    DEFF Research Database (Denmark)

    Fristrup, Peter; Ahlquist, Mårten Sten Gösta; Tanner, David Ackland;

    2008-01-01

    The reactivity of intermediates in palladium-catalyzed allylic alkylation was investigated using DFT (B3LYP) calculations including a PB-SCRF solvation model. In the presence of both phosphine and chloride ligands, the allyl intermediate is in equilibrium between a cationic eta(3)-allylPd complex...... with two phosphine ligands, the corresponding neutral complex with one phosphine and one chloride ligand, and a neutral eta(1)-allylPd complex with one chloride and two phosphine ligands. The eta(1)-complex is unreactive toward nucleophiles. The cationic eta(3)-complex is the intermediate most...

  14. Sulindac sulfide selectively increases sensitivity of ABCC1 expressing tumor cells to doxorubicin and glutathione depletion

    Science.gov (United States)

    Whitt, Jason D.; Keeton, Adam B.; Gary, Bernard D.; Sklar, Larry A.; Sodani, Kamlesh; Chen, Zhe-Sheng; Piazza, Gary A.

    2016-01-01

    Abstract ATP-binding cassette (ABC) transpo rters ABCC1 (MRP1), ABCB1 (P-gp), and ABCG2 (BCRP) contribute to chemotherapy failure. The primary goals of this study were to characterize the efficacy and mechanism of the non­steroidal anti-inflammatory drug (NSAID), sulindac sulfide, to reverse ABCC1 mediated resistance to chemother­apeutic drugs and to determine if sulindac sulfide can influence sensitivity to chemotherapeutic drugs independently of drug efflux. Cytotoxicity assays were performed to measure resistance of ABC-expressing cell lines to doxoru­bicin and other chemotherapeutic drugs. NSAIDs were tested for the ability to restore sensitivity to resistance selected tumor cell lines, as well as a large panel of standard tumor cell lines. Other experiments characterized the mechanism by which sulindac sulfide inhibits ABCC1 substrate and co-substrate (GSH) transport in isolated membrane vesicles and intact cells. Selective reversal of multi-drug resistance (MDR), decreased efflux of doxor­ubicin, and fluorescent substrates were demonstrated by sulindac sulfide and a related NSAID, indomethacin, in resistance selected and engineered cell lines expressing ABCC1, but not ABCB1 or ABCG2. Sulindac sulfide also inhibited transport of leukotriene C4 into membrane vesicles. Sulindac sulfide enhanced the sensitivity to doxoru­bicin in 24 of 47 tumor cell lines, including all melanoma lines tested (7-7). Sulindac sulfide also decreased intra­cellular GSH in ABCC1 expressing cells, while the glutathione synthesis inhibitor, BSO, selectively increased sensitivity to sulindac sulfide induced cytotoxicity. Sulindac sulfide potently and selectively reverses ABCC1-mediated MDR at clinically achievable concentrations. ABCC1 expressing tumors may be highly sensitive to the direct cytotoxicity of sulindac sulfide, and in combination with chemotherapeutic drugs that induce oxidative stress.

  15. Sulfide Oxidation in the Anoxic Black-Sea Chemocline

    DEFF Research Database (Denmark)

    JØRGENSEN, BB; FOSSING, H.; WIRSEN, CO; JANNASCH, HW

    1991-01-01

    The depth distributions of O2 and H2S and of the activity of chemical or bacterial sulfide oxidation were studied in the chemocline of the central Black Sea. Relative to measurements from earlier studies, the sulfide zone had moved upwards by 20-50 m and was now (May 1988) situated at a depth of 81...... per day, occurred in anoxic water at the top of the sulfide zone concurrent with the highest rates of dark CO2 assimilation. The main soluble oxidized products of sulfide were thiosulfate (68-82%) and sulfate. Indirect evidence was presented for the formation of elemental sulfur which accumulated to a...... that the measured H2S oxidation rates were 4-fold higher than could be explained by the downward flux of organic carbon and too high to balance the availability of electron acceptors such as oxidized iron or manganese. A nitrate maximum at the lower boundary of the O2 zone did not extend down to the...

  16. In vitro study on arsenic sulfide (realgar)-induced apoptosis of retinoic acid susceptible or resistant acute promyelocytic leukemia cell lines

    Institute of Scientific and Technical Information of China (English)

    CHEN Si-yu; LIU Shan-xi; LI Xin-min

    2002-01-01

    Objective: To further understand the possible mechanisms of arsenic sulfide (realgar) in the treatment of acute promyelocytic leukemia (APL). Methods: All-trans retinoic acid (ATRA)-susceptible APL cell line (NB4 cells) and ATRA-resistant APL cell line (MR2 subclone) were used as models in vitro. At various times after incubated with various concentrations of realgar, NB4 and MR2 cells were observed by cell viability, cell proliferation and cell morphology; cell cycle and the expression of Annexin V were assayed by flow cytometry. Results: Cell viability and proliferation of NB4 and MR2 cells were inhibited after the treatment,to some extent, in a dose and time dependent manner. 177-711 μg/L of realgar treated NB4 and MR2 cell presented morphologically some features of apoptotic cells such as intact cell membrane, chromatin condensation and nuclear fragmentation, apoptosis body could be found by electron microscopy as well. Sub-G1 ceils andcell cycle arrest were observed by flow cytometry. The proportion of Annexin V -FITC+/PI cells, which represent apoptotic cells, was up-regulated. Conclusion: Realgar could induce apoptosis of acute promyelocytic leukemia cell despite its susceptibility to retinoic acid in the way that may be different from retinoic acid.

  17. Synthetic and Mechanistic Studies of Strained Heterocycle Opening Reactions Mediated by Zirconium(IV) Imido Complexes

    OpenAIRE

    Blum, Suzanne A.; Rivera, Vicki A.; Ruck, Rebecca T.; Michael, Forrest E.; Bergman, Robert G.

    2005-01-01

    The reactions of the bis(cyclopentadienyl)(tert-butylimido)zirconium complex (Cp2Zr=N-t-Bu)(THF) (1) with epoxides, aziridines, and episulfides were investigated. Heterocycles without accessible β-hydrogens undergo insertion/protonation of the C–X bond to produce 1,2-amino alcohols (X = O) and 1,2-diamines (X = NR), whereas heterocycles with accessible β-hydrogens undergo elimination/protonation to produce allylic alcohols (X = O) and allylic sulfides (X = S). Mechanistic investigations suppo...

  18. Separate recovery of copper and zinc from acid mine drainage using biogenic sulfide

    International Nuclear Information System (INIS)

    Precipitation of metals from acid mine drainage (AMD) using sulfide gives the possibility of selective recovery due to different solubility product of each metal. Using sulfate reducing bacteria to produce sulfide for that purpose is advantageous due to in situ and on-demand sulfide production. In this study, separate precipitation of Cu and Zn was studied using sulfide produced in anaerobic baffled reactor (ABR). ABR fed with ethanol (1340 mg/L chemical oxygen demand (COD)) and sulfate (2000 mg/L) gave a stable performance with 65% sulfate reduction, 85% COD removal and around 320 mg/L sulfide production. Cu was separately precipitated at low pH (pH 2 gas. Cu precipitation was complete within 45-60 min and Zn did not precipitate during Cu removal. The Cu precipitation rate increased with initial Cu concentration. After selective Cu precipitation, Zn recovery was studied using ABR effluent containing sulfide and alkalinity. Depending on initial sulfide/Zn ratio, removal efficiency varied between 84 and 98%. The low pH of Zn bearing AMD was also increased to neutral values using alkalinity produced by sulfate reducing bacteria in ABR. The mode of particle size distribution of ZnS and CuS precipitates was around 17 and 46 μm, respectively.

  19. Variation in sulfide tolerance of photosystem II in phylogenetically diverse cyanobacteria from sulfidic habitats

    Science.gov (United States)

    Miller, Scott R.; Bebout, Brad M.

    2004-01-01

    Physiological and molecular phylogenetic approaches were used to investigate variation among 12 cyanobacterial strains in their tolerance of sulfide, an inhibitor of oxygenic photosynthesis. Cyanobacteria from sulfidic habitats were found to be phylogenetically diverse and exhibited an approximately 50-fold variation in photosystem II performance in the presence of sulfide. Whereas the degree of tolerance was positively correlated with sulfide levels in the environment, a strain's phenotype could not be predicted from the tolerance of its closest relatives. These observations suggest that sulfide tolerance is a dynamic trait primarily shaped by environmental variation. Despite differences in absolute tolerance, similarities among strains in the effects of sulfide on chlorophyll fluorescence induction indicated a common mode of toxicity. Based on similarities with treatments known to disrupt the oxygen-evolving complex, it was concluded that sulfide toxicity resulted from inhibition of the donor side of photosystem II.

  20. Sulfide stress cracking of pipeline steels

    International Nuclear Information System (INIS)

    The problem of the sulfide stress corrosion cracking of pipeline steels and their welded joints have been presented for pipeline steels. Results of hydrogen sulfide stress cracking inhibitors and corrosion inhibitors of three types protective actions on pipeline steels of two grades petroleum range of products are given. (author)

  1. Ammonia and hydrogen sulfide removal using biochar

    Science.gov (United States)

    Reducing ammonia and hydrogen sulfide emissions from livestock facilities is an important issue for many communities and livestock producers. Ammonia has been regarded as odorous, precursor for particulate matter (PM), and contributed to livestock mortality. Hydrogen sulfide is highly toxic at elev...

  2. Alloy selection for sulfidation: oxidation resistance in coal gasification environments

    Energy Technology Data Exchange (ETDEWEB)

    Bradshaw, R.W.; Stoltz, R.E.

    1980-01-01

    A series of iron-nickel-chromium and nickel-chromium alloys were studied for their combined sulfidation-oxidation resistance in simulated coal gasification environments. All alloys contained a minimum of 20 w/o chromium, and titanium and aluminum in the range 0 to 4 w/o. Corrosion resistance was evaluated at 1255/sup 0/K (1800/sup 0/F) in both high BTU and low BTU coal gasification atmospheres with 1 v/o H/sub 2/S. Titanium at levels greater than 1 w/o imparted significant sulfidation resistance due to an adherent, solid solution chromium-titanium oxide layer which prevented sulfur penetration. Aluminum was less effective in preventing sulfidation since surface scales were not adherent. Of the commercial alloys tested, Nimomic 81, Pyromet 31, IN801, and IN825 exhibited the best overall corrosion resistance. However, futher alloy development, tailored to produce solid solution chromium-titanium oxide scales, may lead to alloys with greater sulfidation-oxidation resistance than those investigated here.

  3. Adsorption characteristics of thiobacillus ferrooxidans on surface of sulfide minerals

    Institute of Scientific and Technical Information of China (English)

    LIU Jian-she; XIE Xue-hui; LI Bang-mei; DONG Qing-hai

    2005-01-01

    By using thiobacillus ferrooxidans (T.f) from Qixiashan, Hubei Province, China, the adsorption characteristics of T.f on surface of sulfide mineral were studied. The influences of adsorption time, pH value, temperature, initial inoculated concentration of bacteria, concentration of sulfide mineral powder, and variety of minerals on the adsorption characteristics were firstly investigated by using the ninhydrin colorimetric method, and the changes of contact angles and Zeta potentials of mineral surface during the bacterial adsorption were then determined. The results show that when the leaching experiments are performed for a long time from several days to a month, the maximal quantity of adsorption of T.f on the surface of pyrite is obtained under the following conditions: leaching for 20 d, pH value in range of 1-2 and temperature at 30 ℃, respectively; when the bio-leaching experiments are performed for a shorter leaching time, the maximal quantity of adsorption is obtained under the conditions: bio-leaching for 2 h, at 2.4×10 7 cell/mL of initial inoculated bacteria concentration, and at 10% of mineral powder concentration; and the adsorption quantities are different form one sulfide mineral to another, and the adsorption of T.f on the surface of sulfide minerals includes three phases: increasing phase, stationary phase and decreasing phase.

  4. Weathering of sulfides on Mars

    Science.gov (United States)

    Burns, Roger G.; Fisher, Duncan S.

    1987-01-01

    Pyrrhotite-pentlandite assemblages in mafic and ultramafic igneous rocks may have contributed significantly to the chemical weathering reactions that produce degradation products in the Martian regolith. By analogy and terrestrial processes, a model is proposed whereby supergene alteration of these primary Fe-Ni sulfides on Mars has generated secondary sulfides (e.g., pyrite) below the water table and produced acidic groundwater containing high concentrations of dissolved Fe, Ni, and sulfate ions. The low pH solutions also initiated weathering reactions of igneous feldspars and ferromagnesian silicates to form clay silicate and ferric oxyhydroxide phases. Near-surface oxidation and hydrolysis of ferric sulfato-and hydroxo-complex ions and sols formed gossan above the water table consisting of poorly crystalline hydrated ferric sulfates (e.g., jarosite), oxides (ferrihydrite, goethite), and silica (opal). Underlying groundwater, now permafrost contains hydroxo sulfato complexes of Fe, Al, Mg, Ni, which may be stabilized in frozen acidic solutions beneath the surface of Mars. Sublimation of permafrost may replenish colloidal ferric oxides, sulfates, and phyllosilicates during dust storms on Mars.

  5. Inhibition of bladder cancer cell proliferation by allyl isothiocyanate (mustard essential oil)

    Energy Technology Data Exchange (ETDEWEB)

    Sávio, André Luiz Ventura, E-mail: savio.alv@gmail.com [UNESP – Universidade Estadual Paulista, Faculdade de Medicina de Botucatu, Departamento de Patologia, Botucatu, SP (Brazil); Nicioli da Silva, Glenda [UFOP – Universidade Federal de Ouro Preto, Escola de Farmácia, Departamento de Análises Clínicas, Ouro Preto, MG (Brazil); Salvadori, Daisy Maria Fávero [UNESP – Universidade Estadual Paulista, Faculdade de Medicina de Botucatu, Departamento de Patologia, Botucatu, SP (Brazil)

    2015-01-15

    Highlights: • AITC inhibits mutant and wild-type TP53 cell proliferation. • Morphological changes and cells debris were observed after AITC treatment in both cells. • BAX and BCL2 expression modulation was observed in wild-type TP53 cells. • BCL2, BAX and ANLN increased and S100P decreased expression was detected in mutated TP53 cells. • AITC effects in gene modulation are dependent TP53 gene status. - Abstract: Natural compounds hold great promise for combating antibiotic resistance, the failure to control some diseases, the emergence of new diseases and the toxicity of some contemporary medical products. Allyl isothiocyanate (AITC), which is abundant in cruciferous vegetables and mustard seeds and is commonly referred to as mustard essential oil, exhibits promising antineoplastic activity against bladder cancer, although its mechanism of action is not fully understood. Therefore, the aim of this study was to investigate the effects of AITC activity on bladder cancer cell lines carrying a wild type (wt; RT4) or mutated (T24) TP53 gene. Morphological changes, cell cycle kinetics and CDK1, SMAD4, BAX, BCL2, ANLN and S100P gene expression were evaluated. In both cell lines, treatment with AITC inhibited cell proliferation (at 62.5, 72.5, 82.5 and 92.5 μM AITC) and induced morphological changes, including scattered and elongated cells and cellular debris. Gene expression profiles revealed increased S100P and BAX and decreased BCL2 expression in RT4 cells following AITC treatment. T24 cells displayed increased BCL2, BAX and ANLN and decreased S100P expression. No changes in SMAD4 and CDK1 expression were observed in either cell line. In conclusion, AITC inhibits cell proliferation independent of TP53 status. However, the mechanism of action of AITC differed in the two cell lines; in RT4 cells, it mainly acted via the classical BAX/BCL2 pathway, while in T24 cells, AITC modulated the activities of ANLN (related to cytokinesis) and S100P. These data confirm

  6. Inhibition of bladder cancer cell proliferation by allyl isothiocyanate (mustard essential oil)

    International Nuclear Information System (INIS)

    Highlights: • AITC inhibits mutant and wild-type TP53 cell proliferation. • Morphological changes and cells debris were observed after AITC treatment in both cells. • BAX and BCL2 expression modulation was observed in wild-type TP53 cells. • BCL2, BAX and ANLN increased and S100P decreased expression was detected in mutated TP53 cells. • AITC effects in gene modulation are dependent TP53 gene status. - Abstract: Natural compounds hold great promise for combating antibiotic resistance, the failure to control some diseases, the emergence of new diseases and the toxicity of some contemporary medical products. Allyl isothiocyanate (AITC), which is abundant in cruciferous vegetables and mustard seeds and is commonly referred to as mustard essential oil, exhibits promising antineoplastic activity against bladder cancer, although its mechanism of action is not fully understood. Therefore, the aim of this study was to investigate the effects of AITC activity on bladder cancer cell lines carrying a wild type (wt; RT4) or mutated (T24) TP53 gene. Morphological changes, cell cycle kinetics and CDK1, SMAD4, BAX, BCL2, ANLN and S100P gene expression were evaluated. In both cell lines, treatment with AITC inhibited cell proliferation (at 62.5, 72.5, 82.5 and 92.5 μM AITC) and induced morphological changes, including scattered and elongated cells and cellular debris. Gene expression profiles revealed increased S100P and BAX and decreased BCL2 expression in RT4 cells following AITC treatment. T24 cells displayed increased BCL2, BAX and ANLN and decreased S100P expression. No changes in SMAD4 and CDK1 expression were observed in either cell line. In conclusion, AITC inhibits cell proliferation independent of TP53 status. However, the mechanism of action of AITC differed in the two cell lines; in RT4 cells, it mainly acted via the classical BAX/BCL2 pathway, while in T24 cells, AITC modulated the activities of ANLN (related to cytokinesis) and S100P. These data confirm

  7. Chemical foundations of hydrogen sulfide biology.

    Science.gov (United States)

    Li, Qian; Lancaster, Jack R

    2013-11-30

    Following nitric oxide (nitrogen monoxide) and carbon monoxide, hydrogen sulfide (or its newer systematic name sulfane, H2S) became the third small molecule that can be both toxic and beneficial depending on the concentration. In spite of its impressive therapeutic potential, the underlying mechanisms for its beneficial effects remain unclear. Any novel mechanism has to obey fundamental chemical principles. H2S chemistry was studied long before its biological relevance was discovered, however, with a few exceptions, these past works have received relatively little attention in the path of exploring the mechanistic conundrum of H2S biological functions. This review calls attention to the basic physical and chemical properties of H2S, focuses on the chemistry between H2S and its three potential biological targets: oxidants, metals and thiol derivatives, discusses the applications of these basics into H2S biology and methodology, and introduces the standard terminology to this youthful field. PMID:23850631

  8. Modulation of hydrogen sulfide by vascular hypoxia

    Directory of Open Access Journals (Sweden)

    Osmond JM

    2014-08-01

    Full Text Available Jessica M Osmond, Nancy L KanagyVascular Physiology Group, Department of Cell Biology and Physiology, University of New Mexico Health Sciences Center, Albuquerque, NM, USAAbstract: Hydrogen sulfide (H2S has emerged as a key regulator of cardiovascular function. This gasotransmitter is produced in the vasculature and is involved in numerous processes that promote vascular homeostasis, including vasodilation and endothelial cell proliferation. Although H2S plays a role under physiological conditions, it has become clear in recent years that hypoxia modulates the production and action of H2S. Furthermore, there is growing evidence that H2S is cytoprotective in the face of hypoxic insults. This review focuses on the synthesis and signaling of H2S in hypoxic conditions in the vasculature, and highlights recent studies providing evidence that H2S is a potential therapy for preventing tissue damage in hypoxic conditions.Keywords: H2S, cystathionine γ-lyase, vascular smooth muscle, endothelium

  9. Feasibility of sulfide control in sewers by reuse of iron rich drinking water treatment sludge.

    Science.gov (United States)

    Sun, Jing; Pikaar, Ilje; Sharma, Keshab Raj; Keller, Jürg; Yuan, Zhiguo

    2015-03-15

    Dosage of iron salt is the most commonly used method for sulfide control in sewer networks but incurs high chemical costs. In this study, we experimentally investigate the feasibility of using iron rich drinking water treatment sludge for sulfide control in sewers. A lab-scale rising main sewer biofilm reactor was used. The sulfide concentration in the effluent decreased from 15.5 to 19.8 mgS/L (without dosing) to below 0.7-2.3 mgS/L at a sludge dosing rate achieving an iron to total dissolved inorganic sulfur molar ratio (Fe:S) of 1:1, with further removal of sulfide possible by prolonging the reaction time. In fact, batch tests revealed an Fe consumption to sulfide removal ratio of 0.5 ± 0.02 (mole:mole), suggesting the possible occurrence of other reactions involving the removal of sulfide. Modelling revealed that the reaction between iron in sludge and sulfide has reaction orders of 0.65 ± 0.01 and 0.77 ± 0.02 with respect to the Fe and sulfide concentrations, respectively. The addition of sludge slightly increased the total chemical oxidation demand (tCOD) concentration (by approximately 12%) as expected, but decreased the soluble chemical oxidation demand (sCOD) concentration and methane formation by 7% and 20%, respectively. Some phosphate removal (13%) was also observed at the sludge dosing rate of 1:1 (Fe:S), which is beneficial to nutrient removal from the wastewater. Overall, this study suggests that dosing iron-rich drinking water sludge to sewers could be an effective strategy for sulfide removal in sewer systems, which would also reduce the sludge disposal costs for drinking water treatment works. However, its potential side-effects on sewer sedimentation and on the wastewater treatment plant effluent remain to be investigated. PMID:25616115

  10. Controlled synthesis and morphology evolution of nickel sulfide micro/nanostructure

    International Nuclear Information System (INIS)

    Research highlights: → A facile hydrothermal method has been developed for synthesis of nickel sulfide micro/nanostructure using Ni(NO3)2.6H2O as nickel source, S=C(NH2)2 as sulfur source and 1, 2-ethylenediamin/sodium dodecyl sulfate as surfactant. → Different morphologies such as petal-, urchin- and sphere-like nickel sulfide structures have been synthesized by tuning the reaction time, reaction temperature, and the surfactant. → The relationship of the fluorescence properties with their morphology and phase was studied, and the possible growth mechanism of nickel sulfide structure was proposed based on the morphology evolution of nickel sulfide. → A hydrothermal method to prepare the nickel sulfide, and the phases can be controlled to adjust the photoluminescence intensities in ultraviolet light band. - Abstract: A facile hydrothermal method has been developed for synthesis of nickel sulfide micro/nanostructure using Ni(NO3)2.6H2O as nickel source, S=C(NH2)2 as sulfur source and 1,2-ethylenediamin/sodium dodecyl sulfate as surfactant. Different morphologies such as petal-, urchin- and sphere-like nickel sulfide structures have been synthesized by tuning the reaction time, reaction temperature, and the surfactant. The as-prepared products were characterized by X-ray diffraction, Field-emission scanning electron microscope, and Photoluminescence spectra. The relationship of the fluorescence properties with their morphology and phase was studied, and the possible growth mechanism of nickel sulfide structure was proposed based on the morphology evolution of nickel sulfide.

  11. Indium sulfide precipitation from hydrochloric acid solutions of calcium and sodium chlorides

    International Nuclear Information System (INIS)

    The effect of precipitation duration, acid concentration, indium complexing with chloride ions on the process of indium sulfide chemical precipitation in hydrochloric acid solutions, precipitate composition and dispersity are studied. It is established that indium sulfide solubility increases in solutions with acid concentration exceeding 0.40-0.45 mol/l. Calcium and indium chloride addition to diluted hydrochloric solutions greatly increases the solubility of indium sulfide. The effect of calcium chloride on In2S3 solubility is higher than that of sodium chloride

  12. Effect of Sulfide on Nitrogen Fixation in a Stream Sediment-Water System

    OpenAIRE

    Tam, Tat-Yee; Mayfield, Colin I.; Inniss, William E.; Knowles, Roger

    1982-01-01

    Nitrogen fixation (C2H2 reduction) in a sediment-water system was studied under anaerobic incubation conditions. Sodium sulfide at low concentrations stimulated activity, with a twofold increase in C2H4 production occurring in the presence of 8 μmol of S2− per ml of stream water. Sodium sulfide at concentrations of 16 μmol of S2− per ml or greater inhibited nitrogen fixation, with 64 μmol of S2− per ml being completely inhibitory. Sulfide at levels of 16 μmol/ml or above inhibited CO2 product...

  13. Ni-sulfide particles in NaY-zeolite for combined hydrodesulfurization and hydrocracking purposes

    Science.gov (United States)

    de Bont, P. W.; Vissenberg, M. J.; Boellaard, E.; de Beer, V. H. J.; van Veen, J. A. R.; van Santen, R. A.; van der Kraan, A. M.

    1998-12-01

    The influence of physisorbed water on the formation of nickel-sulfide species in a 57Co doped ion exchange type 57Co:NiNaY catalyst is studied by Mössbauer Emission Spectroscopy. The absence or presence of physisorbed water during sulfidation seems to have no influence on the local nickel environment of the formed Ni-sulfide species. This result is confirmed by EXAFS measurements. In spite of the resemblance found in MES and EXAFS a large difference is found for the initial HDS activities, which is explained by the different particle sizes (HREM) found at the outer surface of the zeolite.

  14. Selective allylic hydroxylation of acyclic terpenoids by CYP154E1 from Thermobifida fusca YX

    Directory of Open Access Journals (Sweden)

    Anna M. Bogazkaya

    2014-06-01

    Full Text Available Allylic alcohols are valuable precursors in the synthesis of pharmaceutical intermediates, agrochemicals and natural products. Regioselective oxidation of parental alkenes is a challenging task for chemical catalysts and requires several steps including protection and deprotection. Many cytochrome P450 enzymes are known to catalyse selective allylic hydroxylation under mild conditions. Here, we describe CYP154E1 from Thermobifida fusca YX that enables this type of oxidation. Several acyclic terpenoids were tested as possible substrates for CYP154E1, and the regio- and chemoselectivity of their oxidation was investigated. Using a previously established bioinformatics approach we identified position 286 in the active site of CYP154E1 which is putatively involved in substrate binding and thereby might have an effect on enzyme selectivity. To tune regio- and chemoselectivity of the enzyme three mutants at position 286 were constructed and used for substrate oxidation. All formed products were analysed with GC–MS and identified using chemically synthesised authentic samples and known compounds as references. Best regioselectivity towards geraniol and nerol was observed with the wild type enzyme mainly leading to 8-hydroxy derivatives (8-hydroxygeraniol or 8-hydroxynerol with high selectivity (100% and 96% respectively. Highest selectivities during the oxidation of geranylacetone and nerylacetone were observed with the following variants: V286F led mainly to 7-hydroxygeranylacetone (60% of the total product and V286A produced predominantly 12-hydroxynerylacetone (75% of total product. Thus, CYP154E1 and its mutants expand the tool-box for allylic hydroxylation in synthetic chemistry.

  15. Enhanced performance of the catalytic conversion of allyl alcohol to 3-hydroxypropionic acid using bimetallic gold catalysts.

    Science.gov (United States)

    Falletta, Ermelinda; Della Pina, Cristina; Rossi, Michele; He, Qian; Kiely, Christopher J; Hutchings, Graham J

    2011-01-01

    One of the strategic building blocks in organic synthesis is 3-hydroxypropionic acid, which is particularly important for the manufacture of high performance polymers. However, to date, despite many attempts using both biological and chemical routes, no large scale effective process for manufacturing 3-hydroxypropionic acid has been developed. One potentially useful starting point is from allyl alcohol, as this can be obtained in principle from the dehydration of glycerol, thereby presenting a bio-renewable green pathway to this important building block. The catalytic transformation of allyl alcohol to 3-hydroxypropionic acid presents interesting challenges in catalyst design, particularly with respect to the control of selectivity among the products that can be expected, as acrylic acid, acrolein and glyceric acid can also be formed. In this paper, we present a novel eco-sustainable catalytic pathway leading to 3-hydroxypropionic acid, which highlights the outstanding potential of gold-based and bimetallic catalysts in the aerobic oxidation of allyl alcohol. PMID:22455056

  16. Synthesis, structural characterization and biological activities of organotin(IV) complexes with 5-allyl-2-hydroxy-3-methoxybenzaldehyde-4-thiosemicarbazone

    Indian Academy of Sciences (India)

    Rosenani A Haque; M A Salam

    2015-09-01

    The organotin(IV) complexes [MeSnCl(L)] (2), [BuSnCl(L)] (3), [PhSnCl(L)] (4) and [Me2Sn(L)] (5) were synthesized by reacting organotin(IV) chloride(s) with 5-allyl-2-hydroxy-3-methoxybenzaldehyde- 4-thiosemicarbazone [H2L], (1)] in presence of KOH in 1:2:1 molar ratio (metal salt: base:ligand). All the complexes have been characterized by elemental analyses, UV-Vis, FT-IR, 1H, 13C and 119Sn NMR spectral studies. The molecular structure of complex 5 has been confirmed by single crystal X-ray diffraction analysis. The ligand, H2L coordinates to Sn(IV) in thiolate form through phenoxide-O, azomethine-N and thiolate-S atoms. The C-Sn-C angle measured from coupling constant 1 (119Sn, 13C) for dimethyltin(IV) complex 5 is 123.4°. The 2 (119Sn, 1H) coupling constant values for complex 2 and 5 are 72.4 and 76.3 Hz, respectively. Proposed geometry for five coordinated Sn(IV) atom is a strongly distorted trigonal bipyramid. Biological studies were preformed in vitro against four bacterial strains which have shown better activities and potential as antibacterial agents.

  17. Two Related Copper(I) π-Complexes Based on 2-Allyl-5-(2-pyridyl)-2H-tetrazole Ligand: Synthesis and Structure of [Cu(2-apyt)NO3] and [Cu(2-apyt)(H2O)](BF4) Compounds.

    Science.gov (United States)

    Slyvka, Yurii; Goreshnik, Evgeny; Pokhodylo, Nazariy; Pavlyuk, Oleksiy; Mys'kiv, Marian

    2016-01-01

    By means of the alternating current electrochemical technique two new π-compounds [Cu(2-apyt)NO3] (1) and [Cu (2-apyt)(H2O)](BF4) (2) have been obtained starting from the mixture of 1-allyl-5-(2-pyridyl)-2H-tetrazole (1-apyt), 2-allyl-5-(2-pyridyl)-2H-tetrazole (2-apyt) and corresponding copper(II) salts, and have been structurally studied. Selective complexation towards 2-allyl- isomer results in a formation of 2-apyt complexes. Copper(I) ion in both 1 and 2 complexes coordinates the allylic C=C bond, one pyridyl and one tetrazole N atoms. In both structures Cu+ center adopts distorted tetrahedral surrounding which additionally includes oxygen of NO3 - in 1 and H2O moiety in 2. Structure 1 is built from [Cu(2-apyt)NO3]2 dimeric fragments. Contrary, participation of H2O in the metal coordination in 2 leads to the infinite [Cu(2-apyt)(H2O)]+n chain construction. To analyze interactions between the particles in 1 and 2 Hirshfeld surface analysis was performed. PMID:27333565

  18. Combined experimental and theoretical mechanistic investigation of the Barbier allylation in aqueous media

    DEFF Research Database (Denmark)

    Dam, Johan Hygum; Fristrup, Peter; Madsen, Robert

    2008-01-01

    The Barbier allylation of a series of para-substituted benzaldehydes with allylbromide in the presence of Zn, In, Sn, Sb, Bi, and Mg was investigated using competition experiments. In all cases, the slope of the Hammett plots indicated a build-up of negative charge in the selectivity-determining ...... effect of solvent described by a polarized continuum model. The calculated secondary deuterium isotope effects based on this mechanism were found to be in good agreement with experimental values, thus adding further support to this mechanistic scenario....

  19. Synthesis of Aryl Allyl Ether in the Recyclable Ionic Liquid [bmim]PF6

    Institute of Scientific and Technical Information of China (English)

    Zhou Mei-Yun; Li Yi-Qun; Xu Xin-Ming

    2004-01-01

    Ionic liquids, especially imidazonium salts, have recently gained recognition as possible environmentally benign alternative chemical process solvents. This is mainly due to their nonvolatile nature, insolubility in some solvents as well as their ability to dissolve a wide range of organic and inorganic materials, allowing the ionic liquids easy recovery and recycling. Examples of their application in organic reactions have been summarized in a number of recent review articles.1Aryl allyl ether is very useful intermediate in organic synthesis. The Williamson reaction is a well knows method for the preparation ethers. However, the reaction of alkylating agents with the phenoxide ions was conventionally carried out in the organic solvents. The usual solvents for this type of reaction are DCM, 2 DMSO, 3 DMF, 4 CH3CN5 etc. With the current desire to avoid the use of organic molecular solvents in organic synthesis, we decide to investigate the use of the ionic liquid for the alternative solvent for the Williamson reaction to prepare the aryl allyl ethers. The ionic liquid employed here was the moisture stable 1-butyl-3-methylimidazolium hexafluorophosphate [bmim]PF6.6 The ionic liquid is non-volatile, thermally stable, and depending on the anion, can present low immiscible with water,alkanes and dialky ethers. We have now found that aryl allyl ethers can have been obtained from various phenols and allyl bromide in the presence of potassium hydroxide in [bmim]PF6 as a replacement for classical organic solvents in the ambient temperature. The results are shown in Scheme 1.The reaction were carried out by simple mixing the phenolwith the ally bromide and potassium hydroxide in [bmim]PF6 and stirred at room temperature for 4h. The results are summarized in Table 1.In conclusion, Williamson reaction can be successfully conducted in ionic liquid [bmim]PF6 with a number of advantages: the procedure is simple, the reaction condition is mild and the yields are excellent

  20. Non-thermal plasma destruction of allyl alcohol in waste gas: kinetics and modelling

    Science.gov (United States)

    DeVisscher, A.; Dewulf, J.; Van Durme, J.; Leys, C.; Morent, R.; Van Langenhove, H.

    2008-02-01

    Non-thermal plasma treatment is a promising technique for the destruction of volatile organic compounds in waste gas. A relatively unexplored technique is the atmospheric negative dc multi-pin-to-plate glow discharge. This paper reports experimental results of allyl alcohol degradation and ozone production in this type of plasma. A new model was developed to describe these processes quantitatively. The model contains a detailed chemical degradation scheme, and describes the physics of the plasma by assuming that the fraction of electrons that takes part in chemical reactions is an exponential function of the reduced field. The model captured the experimental kinetic data to less than 2 ppm standard deviation.

  1. N-(2-Allyl-4-ethoxy-2H-indazol-5-yl-4-methylbenzenesulfonamide

    Directory of Open Access Journals (Sweden)

    Hakima Chicha

    2014-05-01

    Full Text Available The indazole ring system of the title compound, C19H21N3O3S, is almost planar (r.m.s. deviation = 0.0192 Å and forms dihedral angles of 77.99 (15 and 83.9 (3° with the benzene ring and allyl group, respectively. In the crystal, centrosymmetrically related molecules are connected by pairs of N—H...O hydrogen bonds into dimers, which are further linked by C—H...O hydrogen bonds, forming columns parallel to the b axis.

  2. N-(1-Allyl-3-chloro-4-ethoxy-1H-indazol-5-yl-4-methylbenzenesulfonamide

    Directory of Open Access Journals (Sweden)

    Hakima Chicha

    2014-06-01

    Full Text Available In the title compound, C19H20ClN3O3S, the benzene ring is inclined to the indazole ring system by 51.23 (8°. In the crystal, molecules are linked by pairs of N—H...O hydrogen bonds, forming inversion dimers which stack in columns parallel to [011]. The atoms in the allyl group are disordered over two sets of sites with an occupancy ratio of 0.624 (8:0.376 (8.

  3. Non-thermal plasma destruction of allyl alcohol in waste gas: kinetics and modelling

    International Nuclear Information System (INIS)

    Non-thermal plasma treatment is a promising technique for the destruction of volatile organic compounds in waste gas. A relatively unexplored technique is the atmospheric negative dc multi-pin-to-plate glow discharge. This paper reports experimental results of allyl alcohol degradation and ozone production in this type of plasma. A new model was developed to describe these processes quantitatively. The model contains a detailed chemical degradation scheme, and describes the physics of the plasma by assuming that the fraction of electrons that takes part in chemical reactions is an exponential function of the reduced field. The model captured the experimental kinetic data to less than 2 ppm standard deviation

  4. Unusual selectivity-determining factors in the phosphine-free Heck arylation of allyl ethers

    DEFF Research Database (Denmark)

    Ambrogio, I.; Fabrizi, G.; Cacchi, S.;

    2008-01-01

    tolerates a variety of functional groups, including ether, amide, alcohol, aldehyde, ketone, ester, cyano, carboxylic acid, and nitro groups. Ortho-substituted arylating agents afforded moderate yields in some cases, though good to high yields were obtained with o-iodotoluene, iodovanillin, and 1......The Heck reaction of aryl iodides and bromides with allyl ethers has been investigated. Using phosphinefree Pd(OAc)(2) in DNIF at 90 degrees C in the presence of Bu4NOAc, the reaction gave cinnamyl derivatives, usually in good to high yields, with a wide range of aryl halides. The reaction...

  5. Mild and selective vanadium-catalyzed oxidation of benzylic, allylic, and propargylic alcohols using air.

    Science.gov (United States)

    Hanson, Susan K; Wu, Ruilian; Silks, L A Pete

    2011-04-15

    Transition metal-catalyzed aerobic alcohol oxidation is an attractive method for the synthesis of carbonyl compounds, but most catalytic systems feature precious metals and require pure oxygen. The vanadium complex (HQ)(2)V(V)(O)(O(i)Pr) (2 mol %, HQ = 8-quinolinate) and NEt(3) (10 mol %) catalyze the oxidation of benzylic, allylic, and propargylic alcohols with air. The catalyst can be easily prepared under air using commercially available reagents and is effective for a wide range of primary and secondary alcohols. PMID:21434606

  6. Direct asymmetric allylic alkenylation of N-itaconimides with Morita-Baylis-Hillman carbonates

    KAUST Repository

    Yang, Wenguo

    2012-08-03

    The asymmetric allylic alkenylation of Morita-Baylis-Hillman (MBH) carbonates with N-itaconimides as nucleophiles has been developed using a commercially available Cinchona alkaloid catalyst. A variety of multifunctional chiral α-methylene-β-maleimide esters were attained in moderate to excellent yields (up to 99%) and good to excellent enantioselectivities (up to 91% ee). The origin of the regio- and stereoselectivity was verified by DFT methods. Calculated geometries and relative energies of various transition states strongly support the observed regio- and enantioselectivity. © 2012 American Chemical Society.

  7. Lanthanum triflate triggered synthesis of tetrahydroquinazolinone derivatives of N-allyl quinolone and their biological assessment

    Directory of Open Access Journals (Sweden)

    Jardosh Hardik H.

    2012-01-01

    Full Text Available A series of 24 derivatives of tetrahydroquinazolinone has been synthesized by one-pot cyclocondensation reaction of N-allyl quinolones, cyclic β-diketones and (thiourea/N-phenylthiourea in presence of lanthanum triflate catalyst. This methodology allowed us to achieve the products in excellent yield by stirring at room temperature. All the synthesized compounds were investigated against a representative panel of pathogenic strains using broth microdilution MIC (minimum inhibitory concentration method for their in vitro antimicrobial activity. Amongst these sets of heterocyclic compounds 5h, 6b, 6h, 5f, 5l, 5n and 6g found to have admirable activity.

  8. Can Hydrogen Sulfide Gas Be a Biosignature in a Habitable Exoplanet?

    Science.gov (United States)

    Hu, Renyu; Seager, S.; Bains, W.

    2011-05-01

    A group of microorganisms can disproportionate sulfite and elemental sulfur into sulfide and sulfate to obtain energy for a living. We explore if the sulfide produced by microorganisms can alter the atmospheric composition to manifest in the spectrum of a habitable exoplanet. We consider a dry (i.e., limited ocean cover) habitable planet of Earth size and mass, orbiting a Sun-like star. As on Earth, volcanoes release sulfur as sulfur dioxide and hydrogen sulfide, but the volcanic production of hydrogen sulfide is limited by the scarcity of water. In the meantime, in our scenario, microbes can flourish in the ocean and effectively make use of the energy gained from the sulfur disproportion and release sulfide as the metabolic byproduct. The metabolic sulfur disproportion can enhance the overall outgassing rate of hydrogen sulfide by nearly one order of magnitude over the non-biological emission. To study the atmospheric response to this enhancement, we build a one-dimensional chemical transport model that treats all O, H and S bearing species and the relevant photochemical and chemical reactions. The vertical transport is approximated with the eddy diffusion. We also consider the formation and the sedimentation of elemental sulfur aerosols and sulfate aerosols in the atmosphere and explore the effect of aerosol particle size on the chemistry and the radiative transfer. To establish hydrogen sulfide as a biosignature, we need to understand the atmospheric response to the sulfide outgassing, the spectral features of hydrogen sulfide and its photochemical products, and the volcanic release of H2S. The current work will address the first two problems, and the main uncertainty will remain at the possible false positives due to the volcanism.

  9. Hydrogen sulfide production from subgingival plaque samples.

    Science.gov (United States)

    Basic, A; Dahlén, G

    2015-10-01

    Periodontitis is a polymicrobial anaerobe infection. Little is known about the dysbiotic microbiota and the role of bacterial metabolites in the disease process. It is suggested that the production of certain waste products in the proteolytic metabolism may work as markers for disease severity. Hydrogen sulfide (H2S) is a gas produced by degradation of proteins in the subgingival pocket. It is highly toxic and believed to have pro-inflammatory properties. We aimed to study H2S production from subgingival plaque samples in relation to disease severity in subjects with natural development of the disease, using a colorimetric method based on bismuth precipitation. In remote areas of northern Thailand, adults with poor oral hygiene habits and a natural development of periodontal disease were examined for their oral health status. H2S production was measured with the bismuth method and subgingival plaque samples were analyzed for the presence of 20 bacterial species with the checkerboard DNA-DNA hybridization technique. In total, 43 subjects were examined (age 40-60 years, mean PI 95 ± 6.6%). Fifty-six percent had moderate periodontal breakdown (CAL > 3  7 mm) on at least one site. Parvimonas micra, Filifactor alocis, Porphyromonas endodontalis and Fusobacterium nucleatum were frequently detected. H2S production could not be correlated to periodontal disease severity (PPD or CAL at sampled sites) or to a specific bacterial composition. Site 21 had statistically lower production of H2S (p = 0.02) compared to 16 and 46. Betel nut chewers had statistically significant lower H2S production (p = 0.01) than non-chewers. Rapid detection and estimation of subgingival H2S production capacity was easily and reliably tested by the colorimetric bismuth sulfide precipitation method. H2S may be a valuable clinical marker for degradation of proteins in the subgingival pocket. PMID:25280920

  10. Pelletizing of sulfide molybdenite concentrates

    Science.gov (United States)

    Palant, A. A.

    2007-04-01

    The results of a pelletizing investigation using various binding components (water, syrup, sulfite-alcohol distillery grains, and bentonite) of the flotation sulfide molybdenite concentrate (˜84% MoS2) from the Mongolian deposit are discussed. The use of syrup provides rather high-strength pellets (>3 N/pellet or >300 g/pellet) of the required size (2 3 mm) for the consumption of 1 kg binder per 100 kg concentrate. The main advantage of the use of syrup instead of bentonite is that the molybdenum cinder produced by oxidizing roasting of raw ore materials is not impoverished due to complete burning out of the syrup. This fact exerts a positive effect on the subsequent hydrometallurgical process, decreasing molybdenum losses related to dump cakes.

  11. Adequate hydrogen sulfide, healthy circulation

    Institute of Scientific and Technical Information of China (English)

    DU Jun-bao; CHEN Stella; JIN Hong-fang; TANG Chao-shu

    2011-01-01

    Previously,hydrogen sulfide (H2S) was considered to be a toxic gas.However,recently it was discovered that it could be produced in mammals and even in plants,throughtheproductionandmetabolismof sulfur-containing amino acids.In mammals,H2S is mainly catalyzed by cystathionine-γ-lyase (CSE),cystathionin-β-lyase (CBS) and 3-mercaptopyruvate sulfurtransferase (MPST) with the substrate of L-cysteine.Endogenous H2S exerts many important physiological and pathophysiological functions,including hypotensive action,vasorelaxation,myocardial dilation,inhibition of smooth muscle cell proliferation,and antioxidatve actions.Importantly,it plays a very important role in the pathogenesis of systemic hypertension,pulmonary hypertension,atherosclerosis,myocardialinjury,angiogenesis,hyperhomocysteinemi aandshock.Therefore,H2S is now being considered to be a novel gasotransmitter after nitric oxide and carbon monoxide in the regulation of circulatory system.

  12. How selection offsets sulfide corrosion

    International Nuclear Information System (INIS)

    Steels in Girdler heavy water plants are generally required to withstand wet hydrogen sulfide or its aqueous solution. The reasons for selecting various grades for various locations are explained. Information on welding methods is given, and the codes applicable are listed. Carbon steel can be used only where fluid velocity is low. Sections which fail completely if pitted are made of AISI 316 stainless steel. Diaphragms and other very thin parts located in the stagnant fluid are made of Inconel 625. Where solution-annealing of stainless steels at 1000 deg C after welding is not feasible, low-carbon grades (304L, 316L) are used. Some failures are depicted. All castings are completely radiographically examined. (N.D.H.)

  13. Re-Os sulfide (chalcopyrite, pyrite and molybdenite) systematics and fluid inclusion study of the Duobaoshan porphyry Cu (Mo) deposit, Heilongjiang Province, China

    Science.gov (United States)

    Liu, Jun; Wu, Guang; Li, Yuan; Zhu, Mingtian; Zhong, Wei

    2012-04-01

    The Duobaoshan porphyry deposit, located in the northwestern part of the Lesser Hinggan Range, is one of the biggest porphyry Cu (Mo) deposits in the Central Asian orogenic belt in China. The Duobaoshan porphyry deposit occurs in granodiorite and volcanic rocks of the Middle Ordovician Duobaoshan Formation. Six types of veins have been identified in three ore-forming stages as follows: a quartz-potassic feldspar vein in the early ore-forming stage, an early stage quartz-molybdenite vein, late stage quartz-molybdenite and quartz-chalcopyrite-pyrite veins in the middle ore-forming stage, and quartz-pyrite and calcite-quartz veins in the late ore-forming stage. The following four types of fluid inclusions are distinguished from various quartz veins: two-phase aqueous, pure gas phase, CO2-bearing and daughter mineral-bearing inclusions. The ore-forming fluid for the early ore-forming stage belongs to the H2O-CO2-NaCl system, which is characterized by high temperatures (>550 °C), intermediate salinities (16.2-18.1 wt% NaCl eqv.) and high CO2 content. The ore-forming fluid from the middle ore-forming stage evolved to the H2O-CO2-NaCl system, which is characterized by intermediate to high temperatures (230-450 °C) and high/low salinities (0.8 to >65.3 wt% NaCl eqv.) and is also rich in CO2 and metals. The ore-forming fluid finally reached cool temperatures (110-200 °C), low salinities (3.9-8.4 wt% NaCl eqv.) and was CO2-poor. Intensive fluid immiscibility or boiling occurred when the ore-forming fluid with temperatures of 230-450 °C and pressures of 10-41 MPa ascended to 4.1 km, inducing the escape of CO2, depressing the solubility of fluid, and depositing abundant metal sulfides. The total Re and Os concentrations of chalcopyrite and pyrite range from 0.15 to 2.95 μg/g and 0.74 to 15.01 ng/g, respectively. Analyses of seven chalcopyrite and pyrite samples yielded isochron ages of 482-486 Ma, and the model age of one molybdenite sample is 485.6 ± 3.7 Ma. The

  14. Framework to predict optimal buffer layer pairing for thin film solar cell absorbers: A case study for tin sulfide/zinc oxysulfide

    Energy Technology Data Exchange (ETDEWEB)

    Mangan, Niall M.; Brandt, Riley E.; Steinmann, Vera; Jaramillo, R.; Poindexter, Jeremy R.; Chakraborty, Rupak; Buonassisi, Tonio [Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Yang, Chuanxi; Park, Helen Hejin; Zhao, Xizhu; Gordon, Roy G. [Harvard University, Cambridge, Massachusetts 02138 (United States)

    2015-09-21

    An outstanding challenge in the development of novel functional materials for optoelectronic devices is identifying suitable charge-carrier contact layers. Herein, we simulate the photovoltaic device performance of various n-type contact material pairings with tin(II) sulfide (SnS), a p-type absorber. The performance of the contacting material, and resulting device efficiency, depend most strongly on two variables: conduction band offset between absorber and contact layer, and doping concentration within the contact layer. By generating a 2D contour plot of device efficiency as a function of these two variables, we create a performance-space plot for contacting layers on a given absorber material. For a simulated high-lifetime SnS absorber, this 2D performance-space illustrates two maxima, one local and one global. The local maximum occurs over a wide range of contact-layer doping concentrations (below 10{sup 16 }cm{sup −3}), but only a narrow range of conduction band offsets (0 to −0.1 eV), and is highly sensitive to interface recombination. This first maximum is ideal for early-stage absorber research because it is more robust to low bulk-minority-carrier lifetime and pinholes (shunts), enabling device efficiencies approaching half the Shockley-Queisser limit, greater than 16%. The global maximum is achieved with contact-layer doping concentrations greater than 10{sup 18 }cm{sup −3}, but for a wider range of band offsets (−0.1 to 0.2 eV), and is insensitive to interface recombination. This second maximum is ideal for high-quality films because it is more robust to interface recombination, enabling device efficiencies approaching the Shockley-Queisser limit, greater than 20%. Band offset measurements using X-ray photoelectron spectroscopy and carrier concentration approximated from resistivity measurements are used to characterize the zinc oxysulfide contacting layers in recent record-efficiency SnS devices. Simulations representative of these

  15. Framework to predict optimal buffer layer pairing for thin film solar cell absorbers: A case study for tin sulfide/zinc oxysulfide

    International Nuclear Information System (INIS)

    An outstanding challenge in the development of novel functional materials for optoelectronic devices is identifying suitable charge-carrier contact layers. Herein, we simulate the photovoltaic device performance of various n-type contact material pairings with tin(II) sulfide (SnS), a p-type absorber. The performance of the contacting material, and resulting device efficiency, depend most strongly on two variables: conduction band offset between absorber and contact layer, and doping concentration within the contact layer. By generating a 2D contour plot of device efficiency as a function of these two variables, we create a performance-space plot for contacting layers on a given absorber material. For a simulated high-lifetime SnS absorber, this 2D performance-space illustrates two maxima, one local and one global. The local maximum occurs over a wide range of contact-layer doping concentrations (below 1016 cm−3), but only a narrow range of conduction band offsets (0 to −0.1 eV), and is highly sensitive to interface recombination. This first maximum is ideal for early-stage absorber research because it is more robust to low bulk-minority-carrier lifetime and pinholes (shunts), enabling device efficiencies approaching half the Shockley-Queisser limit, greater than 16%. The global maximum is achieved with contact-layer doping concentrations greater than 1018 cm−3, but for a wider range of band offsets (−0.1 to 0.2 eV), and is insensitive to interface recombination. This second maximum is ideal for high-quality films because it is more robust to interface recombination, enabling device efficiencies approaching the Shockley-Queisser limit, greater than 20%. Band offset measurements using X-ray photoelectron spectroscopy and carrier concentration approximated from resistivity measurements are used to characterize the zinc oxysulfide contacting layers in recent record-efficiency SnS devices. Simulations representative of these present-day devices suggest

  16. Microbial control of hydrogen sulfide production

    Energy Technology Data Exchange (ETDEWEB)

    Montgomery, A.D.; Bhupathiraju, V.K.; Wofford, N.; McInerney, M.J. [Univ. of Oklahoma, Tulsa, OK (United States)] [and others

    1995-12-31

    A sulfide-resistant strain of Thiobacillus denitrificans, strain F, prevented the accumulation of sulfide by Desulfovibrio desulfuricans when both organisms were grown in liquid medium. The wild-type strain of T. denitrificans did not prevent the accumulation of sulfide produced by D. desulfuricans. Strain F also prevented the accumulation of sulfide by a mixed population of sulfate-reducing bacteria enriched from an oil field brine. Fermentation balances showed that strain F stoichiometrically oxidized the sulfide produced by D. desulfuricans and the oil field brine enrichment to sulfate. The ability of a strain F to control sulfide production in an experimental system of cores and formation water from the Redfield, Iowa, natural gas storage facility was also investigated. A stable, sulfide-producing biofilm was established in two separate core systems, one of which was inoculated with strain F while the other core system (control) was treated in an identical manner, but was not inoculated with strain F. When formation water with 10 mM acetate and 5 mM nitrate was injected into both core systems, the effluent sulfide concentrations in the control core system ranged from 200 to 460 {mu}M. In the test core system inoculated with strain F, the effluent sulfide concentrations were lower, ranging from 70 to 110 {mu}M. In order to determine whether strain F could control sulfide production under optimal conditions for sulfate-reducing bacteria, the electron donor was changed to lactate and inorganic nutrients (nitrogen and phosphate sources) were added to the formation water. When nutrient-supplemented formation water with 3.1 mM lactate and 10 mM nitrate was used, the effluent sulfide concentrations of the control core system initially increased to about 3,800 {mu}M, and then decreased to about 1,100 {mu}M after 5 weeks. However, in the test core system inoculated with strain F, the effluent sulfide concentrations were much lower, 160 to 330 {mu}M.

  17. From a Sequential to a Concurrent Reaction in Aqueous Medium: Ruthenium-Catalyzed Allylic Alcohol Isomerization and Asymmetric Bioreduction.

    Science.gov (United States)

    Ríos-Lombardía, Nicolás; Vidal, Cristian; Liardo, Elisa; Morís, Francisco; García-Álvarez, Joaquín; González-Sabín, Javier

    2016-07-18

    The ruthenium-catalyzed redox isomerization of allylic alcohols was successfully coupled with the enantioselective enzymatic ketone reduction (mediated by KREDs) in a concurrent process in aqueous medium. The overall transformation, formally the asymmetric reduction of allylic alcohols, took place with excellent conversions and enantioselectivities, under mild reaction conditions, employing commercially and readily available catalytic systems, and without external coenzymes or cofactors. Optimization resulted in a multistep approach and a genuine cascade reaction where the metal catalyst and biocatalyst coexist from the beginning. PMID:27258838

  18. Iodine-Catalyzed Decarboxylative Amidation of β,γ-Unsaturated Carboxylic Acids with Chloramine Salts Leading to Allylic Amides.

    Science.gov (United States)

    Kiyokawa, Kensuke; Kojima, Takumi; Hishikawa, Yusuke; Minakata, Satoshi

    2015-10-26

    The iodine-catalyzed decarboxylative amidation of β,γ-unsaturated carboxylic acids with chloramine salts is described. This method enables the regioselective synthesis of allylic amides from various types of β,γ-unsaturated carboxylic acids containing substituents at the α- and β-positions. In the reaction, N-iodo-N-chloroamides, generated by the reaction of a chloramine salt with I2 , function as a key active species. The reaction provides an attractive alternative to existing methods for the synthesis of useful secondary allylic amine derivatives. PMID:26493878

  19. Cobalt-Catalyzed Cross-Coupling of Grignards with Allylic and Vinylic Bromides: Use of Sarcosine as a Natural Ligand.

    Science.gov (United States)

    Frlan, Rok; Sova, Matej; Gobec, Stanislav; Stavber, Gaj; Časar, Zdenko

    2015-08-01

    Sarcosine was discovered to be an excellent ligand for cobalt-catalyzed carbon-carbon cross-coupling of Grignard reagents with allylic and vinylic bromides. The Co(II)/sarcosine catalytic system is shown to perform efficiently when phenyl and benzyl Grignards are coupled with alkenyl bromides. Notably, previously unachievable Co-catalyzed coupling of allylic bromides with Grignards to linearly coupled α-products was also realized with Co(II)/sarcosine catalyst. This method was used for efficient preparation of the key intermediate in an alternative synthesis of the antihyperglycemic drug sitagliptin. PMID:26158563

  20. The sulfide oxidation in an electrolytic sulfide oxidizing bioreactor using graphite anode

    International Nuclear Information System (INIS)

    The goal of the present research was the direct conversion of sulfide (an important contaminant in various industrial wastewaters) to sulfate, whose discharge limits are much less stringent than those for sulfide. The electrolysis of sodium sulfide was investigated under different conditions such as: ph, current density and working area etc. along with cyclic voltammetry. By the use of a graphite anode, we achieved near-quantitative electrochemical conversion of sulfide ions to sulfate with current efficiency of 88%. Kinetically, the reaction is first order in current density. The experimental results revealed that the sulfide removal rate of more than 88% could be achieved under the conditions T=30 deg. C, ph = 7, current density of 1 mA/cm/sup 2/ at anode area of 225 cm/sup 2/.The process can be practically coupled with bioreactor for an effective sulfide removal. (author)

  1. Structure formation of soil dispersions in the presence of polyelectrolytes on the basis of allyl alcohol and acryl acid derivatives

    Directory of Open Access Journals (Sweden)

    Amankait Asanov

    2015-09-01

    Full Text Available Some changes of structural composition and surface properties of soil dispersions in the presence of polyelectrolytes, based on allyl alcohol and acryl acid derivatives, have been studied. The results show, that the changes in the structure of soil dispersions composition are connected with the added concentration and pH value, that depend on mole ratio and nature of functional groups, as well as on the nature of counterions and concomitant electrolytes, changing with the conditions of polymer analogous conversion and neutralization reaction. Experimental data show, that the change in the conformational state and the length of the macromolecule has a significant impact on the structure-forming effect and the amount of polyelectrolyte, needed to achieve the same degree of structure-forming effect of soil dispersions. The causes for the revealed reasons are shown on the basis of the results of the experiment. Along with this, it was found that particular changes of structural composition and surface properties of the soil dispersions depend on the type and concentration of the added polyelectrolyte.

  2. Statistic evaluation of cysteine and allyl alcohol as additives for Cu-Zn coatings from citrate baths

    Directory of Open Access Journals (Sweden)

    Julyana Ribeiro Garcia

    2013-04-01

    Full Text Available In the present work, cysteine and allyl alcohol were added to citrate baths as additives to Cu-Zn coatings on steel substrates. In order to verify the effects of the deposition parameters (current density, mechanical stirring speed, and additives on the coating composition, electrochemical behavior, morphology, and microstructure properties of Cu-Zn coatings, the electrodeposition of the alloy was carried out using an experimental composite design 2³, in which these parameters were considered the entry variables and the measured properties were the response variables. The confidence level was 95% and the results were shown as response surface diagrams. It was possible to verify that the current density affected the zinc content in the coating, while the coating produced from cysteine-contained bath presented the worse anticorrosive performance. In a general way, it was possible to observe that the studied parameters affected the morphology, grain size, and the electrochemical behavior of these coatings, although only a few response variables were statistically influenced by them.

  3. Statistic evaluation of cysteine and allyl alcohol as additives for Cu-Zn coatings from citrate baths

    Directory of Open Access Journals (Sweden)

    Julyana Ribeiro Garcia

    2012-01-01

    Full Text Available In the present work, cysteine and allyl alcohol were added to citrate baths as additives to Cu-Zn coatings on steel substrates. In order to verify the effects of the deposition parameters (current density, mechanical stirring speed, and additives on the coating composition, electrochemical behavior, morphology, and microstructure properties of Cu-Zn coatings, the electrodeposition of the alloy was carried out using an experimental composite design 2³, in which these parameters were considered the entry variables and the measured properties were the response variables. The confidence level was 95% and the results were shown as response surface diagrams. It was possible to verify that the current density affected the zinc content in the coating, while the coating produced from cysteine-contained bath presented the worse anticorrosive performance. In a general way, it was possible to observe that the studied parameters affected the morphology, grain size, and the electrochemical behavior of these coatings, although only a few response variables were statistically influenced by them.

  4. Fabrication of Cellulose Film with Enhanced Mechanical Properties in Ionic Liquid 1-Allyl-3-methylimidaxolium Chloride (AmimCl

    Directory of Open Access Journals (Sweden)

    Jinhui Pang

    2013-03-01

    Full Text Available More and more attention has been paid to environmentally friendly bio-based renewable materials as the substitution of fossil-based materials, due to the increasing environmental concerns. In this study, regenerated cellulose films with enhanced mechanical property were prepared via incorporating different plasticizers using ionic liquid 1-allyl-3-methylimidazolium chloride (AmimCl as the solvent. The characteristics of the cellulose films were investigated by scanning electron microscopy (SEM, atomic force microscopy (AFM, thermal analysis (TG, X-ray diffraction (XRD, 13C Solid-state cross-polarization/magic angle spinning nuclear magnetic resonance (CP/MAS NMR and tensile testing. The results showed that the cellulose films exhibited a homogeneous and smooth surface structure. It was noted that the thermal stability of the regenerated cellulose film plasticized with glycerol was increased compared with other regenerated cellulose films. Furthermore, the incorporation of plasticizers dramatically strengthened the tensile strength and improved the hydrophobicity of cellulose films, as compared to the control sample. Therefore, these notable results exhibited the potential utilization in producing environmentally friendly cellulose films with high performance properties.

  5. Influence of the antimicrobial compound allyl isothiocyanate against the Aspergillus parasiticus growth and its aflatoxins production in pizza crust.

    Science.gov (United States)

    Quiles, Juan M; Manyes, Lara; Luciano, Fernando; Mañes, Jordi; Meca, Giuseppe

    2015-09-01

    Aflatoxins (AFs) are secondary metabolites produced by different species of Aspergillus, such as Aspergillus flavus and Aspergillus parasiticus, which possess mutagenic, teratogenic and carcinogenic activities in humans. In this study, active packaging devices containing allyl isothiocyanate (AITC) or oriental mustard flour (OMF) + water were tested to inhibit the growth of A. parasiticus and AFs production in fresh pizza crust after 30 d. The antimicrobial and anti-aflatoxin activities were compared to a control group (no antimicrobial treatment) and to a group added with commercial preservatives (sorbic acid + sodium propionate). A. parasiticus growth was only inhibited after 30 d by AITC in filter paper at 5 μL/L and 10 μL/L, AITC sachet at 5 μL/L and 10 μL/L and OMF sachet at 850 mg + 850 μL of water. However, AFs production was inhibited by all antimicrobial treatments in a dose-dependent manner. More importantly, AITC in a filter paper at 10 μL/L, AITC sachet at 10 μL/L, OMF sachet at 850 mg + 850 μL of water and sorbic acid + sodium propionate at 0.5-2.0 g/Kg completely inhibited AFs formation. The use of AITC in active packaging devices could be a natural alternative to avoid the growth of mycotoxinogenic fungi in refrigerated bakery products in substitution of common commercial preservatives. PMID:26146190

  6. Ocean color and atmospheric dimethyl sulfide: On their mesoscale variability

    OpenAIRE

    Matrai, Patricia A.; Balch, William M; Cooper, David J; Saltzman, Eric S.

    1993-01-01

    The mesoscale variability of dimethyl sulfide (DMS) and ocean color is explored to determine the feasibility of a predictive relationship. During NASA's Global Tropospheric Experiment/Chemical Instrumentation Test and Evaluation (GTE/CITE 3), simultaneous shipboard and aircraft studies were carried out in the North Atlantic, followed by aircraft studies in the South Atlantic. Surface concentrations of chlorophyll a were measured with an airborne spectroradiometer, the Ocean Data Acquisition S...

  7. Kinetics of Indigenous Nitrate Reducing Sulfide Oxidizing Activity in Microaerophilic Wastewater Biofilms

    Science.gov (United States)

    Villahermosa, Desirée; Corzo, Alfonso; Garcia-Robledo, Emilio; González, Juan M.; Papaspyrou, Sokratis

    2016-01-01

    Nitrate decreases sulfide release in wastewater treatment plants (WWTP), but little is known on how it affects the microzonation and kinetics of related microbial processes within the biofilm. The effect of nitrate addition on these properties for sulfate reduction, sulfide oxidation, and oxygen respiration were studied with the use of microelectrodes in microaerophilic wastewater biofilms. Mass balance calaculations and community composition analysis were also performed. At basal WWTP conditions, the biofilm presented a double-layer system. The upper microaerophilic layer (~300 μm) showed low sulfide production (0.31 μmol cm-3 h-1) and oxygen consumption rates (0.01 μmol cm-3 h-1). The anoxic lower layer showed high sulfide production (2.7 μmol cm-3 h-1). Nitrate addition decreased net sulfide production rates, caused by an increase in sulfide oxidation rates (SOR) in the upper layer, rather than an inhibition of sulfate reducing bacteria (SRB). This suggests that the indigenous nitrate reducing-sulfide oxidizing bacteria (NR-SOB) were immediately activated by nitrate. The functional vertical structure of the biofilm changed to a triple-layer system, where the previously upper sulfide-producing layer in the absence of nitrate split into two new layers: 1) an upper sulfide-consuming layer, whose thickness is probably determined by the nitrate penetration depth within the biofilm, and 2) a middle layer producing sulfide at an even higher rate than in the absence of nitrate in some cases. Below these layers, the lower net sulfide-producing layer remained unaffected. Net SOR varied from 0.05 to 0.72 μmol cm-3 h-1 depending on nitrate and sulfate availability. Addition of low nitrate concentrations likely increased sulfate availability within the biofilm and resulted in an increase of both net sulfate reduction and net sulfide oxidation by overcoming sulfate diffusional limitation from the water phase and the strong coupling between SRB and NR-SOB syntrophic

  8. The loss of the hemoglobin H2S-binding function in annelids from sulfide-free habitats reveals molecular adaptation driven by Darwinian positive selection.

    Science.gov (United States)

    Bailly, Xavier; Leroy, Riwanon; Carney, Susan; Collin, Olivier; Zal, Franck; Toulmond, Andre; Jollivet, Didier

    2003-05-13

    The hemoglobin of the deep-sea hydrothermal vent vestimentiferan Riftia pachyptila (annelid) is able to bind toxic hydrogen sulfide (H(2)S) to free cysteine residues and to transport it to fuel endosymbiotic sulfide-oxidising bacteria. The cysteine residues are conserved key amino acids in annelid globins living in sulfide-rich environments, but are absent in annelid globins from sulfide-free environments. Synonymous and nonsynonymous substitution analysis from two different sets of orthologous annelid globin genes from sulfide rich and sulfide free environments have been performed to understand how the sulfide-binding function of hemoglobin appeared and has been maintained during the course of evolution. This study reveals that the sites occupied by free-cysteine residues in annelids living in sulfide-rich environments and occupied by other amino acids in annelids from sulfide-free environments, have undergone positive selection in annelids from sulfide-free environments. We assumed that the high reactivity of cysteine residues became a disadvantage when H(2)S disappeared because free cysteines without their natural ligand had the capacity to interact with other blood components, disturb homeostasis, reduce fitness and thus could have been counterselected. To our knowledge, we pointed out for the first time a case of function loss driven by molecular adaptation rather than genetic drift. If constraint relaxation (H(2)S disappearance) led to the loss of the sulfide-binding function in modern annelids from sulfide-free environments, our work suggests that adaptation to sulfide-rich environments is a plesiomorphic feature, and thus that the annelid ancestor could have emerged in a sulfide-rich environment. PMID:12721359

  9. The bioleaching of different sulfide concentrates using thermophilic bacteria

    Science.gov (United States)

    Torres, F.; Blázquez, M. L.; González, F.; Ballester, A.; Mier, J. L.

    1995-05-01

    The bioleaching of different mineral sulfide concentrates with thermophilic bacteria (genus Sulfolobus @#@) was studied. Since the use of this type of bacteria in leaching systems involves stirring and the control of temperature, the influence of the type of stirring and the pulp density on dissolution rates was studied in order to ascertain the optimum conditions for metal recovery. At low pulp densities, the dissolution kinetic was favored by pneumatic stirring, but for higher pulp densities, orbital stirring produced the best results. A comparative study of three differential concentrates, one mixed concentrate, and one global concentrate was made. Copper and iron extraction is directly influenced by bacterial activity, while zinc dissolution is basically due to an indirect mechanism that is activated in the presence of copper ions. Galvanic interactions between the different sulfides favors the selective bioleaching of some phases (sphalerite and chalcopyrite) and leads to high metal recovery rates. However, the formation of galvanic couples depends on the type of concentrate.

  10. Conversion kinetics for smelt anions: cyanate and sulfide

    Energy Technology Data Exchange (ETDEWEB)

    DeMartini, N.

    2004-07-01

    Cyanate and sulfide are two anions found in the molten salts (smelt) from the kraft recovery boiler of the chemical recovery cycle. Their concentrations in smelt are significantly different, as are their origins. The concentration of cyanate in smelt ranges between 0.4 and 2.1 g OCN{sup -}/kg smelt while the concentration of sulfide ranges between 78 and 115 g S{sup 2-}/kg smelt. Cyanate is a by-product of black liquor combustion. It is formed from organic nitrogen compounds in black liquor during the char burning stage. The charge of the cyanate anion is balanced by the alkali metals found in smelt, namely sodium and potassium. It has been found that the nitrogen in cyanate represents about 30% of the nitrogen entering the recovery boiler with the black liquor. This flow is similar in magnitude to the flows of black liquor nitrogen exiting the recovery boiler as the gaseous compounds NO and N{sub 2}. The method for cyanate analysis used in this work is presented in the Methods chapter of this thesis and Paper I. The results from nitrogen balances at three European kraft pulp mills are discussed in this thesis and Papers II and III, with a focus on the fate of cyanate in the recovery boiler and recausticizing process. Cyanate exits the recovery boiler with the smelt and reacts to form ammonia in the recausticizing solutions of the chemical recovery cycle. Papers IV and V of this thesis focus on the rate of ammonia formation from cyanate in model solutions and in kraft green liquors. The experiments were carried out at temperatures of 80 to 95 deg C, which are temperatures similar to those found in the recausticizing process of a kraft pulp mill. The kinetic studies help clarify the catalytic effect of bicarbonate. A rate equation applicable for use in describing ammonia formation from cyanate in highly alkaline solutions such as pulp mill recovery streams is presented. The sulfide anion, on the other hand, is a desired product of black liquor combustion as the

  11. Formation of Copper Sulfide Artifacts During Electrolytic Dissolution of Steel

    Science.gov (United States)

    Tan, Jia; Pistorius, P. Chris

    2013-06-01

    Based on equilibrium considerations, copper sulfide is not expected to form in manganese-containing steel, yet previous workers reported finding copper sulfide in transmission electron microscope samples which had been prepared by electropolishing. It is proposed that copper sulfide can form during electrolytic dissolution because of the much greater stability of copper sulfide relative to manganese sulfide in contact with an electrolyte containing copper and manganese cations. This mechanism has been demonstrated with aluminum-killed steel samples.

  12. High temperature sulfide corrosion and transport properties of transition metal sulfides

    International Nuclear Information System (INIS)

    An overview is presented of the role of the defect and transport properties of transition metal sulfides on the kinetics and mechanism of high-temperature sulfide corrosion of metals and alloys. It has been shown that due to the very high concentration of defects in common metal sulfides, not only pure metals but also conventional high-temperature alloys (chromia and alumina formers) undergo very rapid degradation in highly sulfidizing environments. Refractory metals (Mo, Nb), on the other hands, are highly resistant to sulfide corrosion, their sulfidation rates being comparable with the oxidation rate of chromium. Also, alloying of common metals by niobium and molybdenum improve considerably corrosion resistance with respect to highly sulfidizing atmospheres. It has demonstrated that Al.-Mo and Al.-Mo-Si alloys shown excellent resistant to sulfidizing environments, these materials being also simultaneously oxidation resistant. Thus, new prospects have been created for the development of a new generation of coating materials, resistant to multicomponent sulfidizing-oxidizing atmospheres, often encountered in many branches of modern technology. (author)

  13. Allyl ethers of the 1-alkoxy-2,3-propandiol

    International Nuclear Information System (INIS)

    With the purpose of study of 1-alkoxy-2,3-propandiol allying reaction wasobtained their mono- and diallyl ethers by authors of this article. Theinitial 1-alkoxy-2,3-propandiol was synthesised from mono chlor-hydrin ofglycerin and alcoholates of alcohols of saturated line (C1-C5) and theirisomers

  14. Polymerizations of beta-substituted allylic arsonium ylides with catalytic amounts of organoboron compounds

    International Nuclear Information System (INIS)

    My Ph.D. work consisted in the generalization and optimization of a new polymerization reaction involving allylic arsonium ylides and catalytic amounts of various boron compounds. Thus, various β-substituted allylic arsonium salts were produced according to synthetic strategies that depended on the nature of the functional group born by the salt. These salts were converted in situ to the corresponding arsonium ylides which were then treated with boron compounds to yield polymers. Our new method of polymerization afforded either non conjugated polyenes that are functionalized every three atoms of carbon, or statistic copolymers, depending on the nature of the group R born on the β position of the ylide. These new polymers cannot be synthesized by usual methods of polymerization. Initial molar ratios of reactants were found to give molar mass control of the synthesized polymers. This controlled polymerization allowed us to produce several bloc copolymers. All the polymers were characterized by NMR techniques, by size exclusion chromatography and, for some of them, by mass spectrometry. Investigation of their physicochemical properties will need additional experiments. (author)

  15. Further exploration of the heterocyclic diversity accessible from the allylation chemistry of indigo

    Directory of Open Access Journals (Sweden)

    Alireza Shakoori

    2015-04-01

    Full Text Available Diversity-directed synthesis based on the cascade allylation chemistry of indigo, with its embedded 2,2’-diindolic core, has resulted in rapid access to new examples of the hydroxy-8a,13-dihydroazepino[1,2-a:3,4-b']diindol-14(8H-one skeleton in up to 51% yield. Additionally a derivative of the novel bridged heterocycle 7,8-dihydro-6H-6,8a-epoxyazepino[1,2-a:3,4-b']diindol-14(13H-one was produced when the olefin of the allylic substrate was terminally disubstituted. Further optimisation also produced viable one-pot syntheses of derivatives of the spiro(indoline-2,9'-pyrido[1,2-a]indol-3-one (65% and pyrido[1,2,3-s,t]indolo[1,2-a]azepino[3,4-b]indol-17-one (72% heterocyclic systems. Ring-closing metathesis of the N,O-diallylic spiro structure and subsequent Claisen rearrangement gave rise to the new (1R,8aS,17aS-rel-1,2-dihydro-1-vinyl-8H,17H,9H-benz[2',3']pyrrolizino[1',7a':2,3]pyrido[1,2-a]indole-8,17-(2H,9H-dione heterocyclic system.

  16. Managing hydrogen sulfide the natural way

    Energy Technology Data Exchange (ETDEWEB)

    Beasley, T.; Abry, R.G.F. [New Paradigm Gas Processing Ltd., Calgary, AB (Canada)

    2003-07-01

    This paper explores the benefits and costs associated with acid gas injection versus flaring and venting. It provides an update of Shell Paques biological gas desulfurization technology and the world's first high pressure application of the technology at the EnCana Bantry Project. The process is particularly well suited to treat sour (acid) natural gases that are currently being flared. It can also be used as an alternative to acid gas injection. Complete removal of hydrogen sulfide can be achieved by selective biotechnological conversion of hydrogen sulfide to elemental sulfur. Compared to conventional processes, this breakthrough technology achieves greater savings in terms of capital and operational costs. The Shell-Paque process produces up to 50 tonnes of sulfur per day with virtually complete conversion of hydrogen sulfide to elemental sulfur, resulting in no hydrogen sulfide based airborne emissions. 2 refs., 2 tabs., 35 figs.

  17. Inorganic sorbents for concentration of hydrogen sulfide

    International Nuclear Information System (INIS)

    Present work is devoted to application of inorganic sorbents for concentration of hydrogen sulfide. The elaboration of method is conducted under controlled concentrations of hydrogen sulphide from 1.00 til 0.01 mg/l.

  18. Sites and reactivity of sulfides in hydro-treatment catalysis: theoretical ab-initio study; Sites et reactivite des sulfures en catalyse d`hydrotraitement: etude theorique ab-initio

    Energy Technology Data Exchange (ETDEWEB)

    Raybaud, P.

    1998-10-28

    Ab-initio calculations within the DFT and GGA have been carried out in an attempt to understand better which property sets the activity of transition metal sulfides (TMS) in the hydro-desulfurization reaction (HDS), a most important step in the refining of crude oil. A systematic study of the structural cohesive and electronic properties of more than thirty bulk TMS has allowed us to find a new simple relationship between the experimental catalytic activities known in HDS, and the properly defined sulfur-metal (S-M) bond energy. On this volcano curve reminiscent of the Sabatier principles, ionic metallic sulfides (as Ni{sub 3}S{sub 2}, Ci{sub 9}S{sub 8}) exhibit the weakest bonds whereas ion-covalent semi-conductors (as MoS{sub 2}) exhibit the strongest bonds: the highest activities correspond to intermediate bond strengths (RuS{sub 2}). Our study of the electronic structure of the MoS{sub 2} edge surfaces has revealed acceptor surface states localized on Coordinatively Unsaturated Mo ions and the significance of those states for the activation of hetero-aromatic molecules like thiophene. On such surfaces, the energetic profiles we establish for the thiophene HDS reaction point out the surface anionic vacancy regeneration steps as rate determining. We have calculated the optimal positions of Co (Ni) in decoration on the MoS{sub 2} edge planes, in excellent agreement with available EXAFS data on real catalysts. Introducing the promoter Co (Ni) induces a lower optimal sulfur coverage and a lower surface S-M bond strength in proportion of the Co (Ni) coverage, and lower for Ni than for Co. Simplified energy profiles for the thiophene HDS reactions on promoted (101-bar 0) surfaces show that the C-S scission step is likely to become rate determining. Our results show altogether that bulk and surface S-M strengths in TMS systems show similar trends, insofar as they are primarily determined by the local electronic structure. (author)

  19. The Search for Interstellar Sulfide Grains

    Science.gov (United States)

    Keller, Lindsay P.; Messenger, Scott

    2010-01-01

    The lifecycle of sulfur in the galaxy is poorly understood. Fe-sulfide grains are abundant in early solar system materials (e.g. meteorites and comets) and S is highly depleted from the gas phase in cold, dense molecular cloud environments. In stark contrast, sulfur is essentially undepleted from the gas phase in the diffuse interstellar medium, indicating that little sulfur is incorporated into solid grains in this environment. It is widely believed that sulfur is not a component of interstellar dust grains. This is a rather puzzling observation unless Fe-sulfides are not produced in significant quantities in stellar outflows, or their lifetime in the ISM is very short due to rapid destruction. Fe sulfide grains are ubiquitous in cometary samples where they are the dominant host of sulfur. The Fe-sulfides (primarily pyrrhotite; Fe(1-x)S) are common, both as discrete 0.5-10 micron-sized grains and as fine (5-10 nm) nanophase inclusions within amorphous silicate grains. Cometary dust particles contain high abundances of well-preserved presolar silicates and organic matter and we have suggested that they should contain presolar sulfides as well. This hypothesis is supported by the observation of abundant Fe-sulfides grains in dust around pre- and post-main sequence stars inferred from astronomical spectra showing a broad 23 micron IR feature due to FeS. Fe-sulfide grains also occur as inclusions in bona fide circumstellar amorphous silicate grains and as inclusions within deuterium-rich organic matter in cometary dust samples. Our irradiation experiments show that FeS is far more resistant to radiation damage than silicates. Consequently, we expect that Fe sulfide stardust should be as abundant as silicate stardust in solar system materials.

  20. Biological removal of air loaded with a hydrogen sulfide and ammonia mixture

    Institute of Scientific and Technical Information of China (English)

    CHEN Ying-xu; YIN Jun; FANG Shi

    2004-01-01

    The nuisance impact of air pollutant emissions from wastewater pumping stations is a major issue of concern to China. Hydrogen sulfide and ammonia are commonly the primary odor and are important targets for removal. An alternative control technology, biofiltration, was studied. The aim of this study is to investigate the potential of unit systems packed with compost in terms of ammonia and hydrogen sulfide emissions treatment, and to establish optimal operating conditions for a full-scale conceptual design. The laboratory scale biofilter packed with compost was continuously supplied with hydrogen sulfide and ammonia gas mixtures. A volumetric load of less than 150 gH2S/(m3· d) and 230 gNH3/(m3· d) was applied for about fifteen weeks. Hydrogen sulfide and ammonia elimination occurred in the biofilter simultaneously. The removal efficiency, removal capacity and removal kinetics in the biofilter were studied. The hydrogen sulfide removal efficiency reached was very high above 99%, and ammonia removal efficiency was about 80%. Hydrogen sulfide was oxidized into sulphate. The ammonia oxidation products were nitrite and nitrate. Ammonia in the biofilter was mainly removed by adsorption onto the carrier material and by absorption into the water fraction of the carrier material. High percentages of hydrogen sulfide or ammonia were oxidized in the first section of the column. Through kinetics analysis, the presence of amrronia did not hinder the hydrogen sulfide removal. According to the relationship between pressure drop and gas velocity for the biofilter and Reynolds number, non-Darcy flow can be assumed to represent the flow in the medium.

  1. Synthesis of zinc sulfide by chemical vapor deposition using an organometallic precursor: Di-tertiary-butyl-disulfide

    Energy Technology Data Exchange (ETDEWEB)

    Vasekar, Parag, E-mail: psvasekar@yahoo.com [Center for Autonomous Solar Power, State University of New York at Binghamton, Binghamton, New York 13902 (United States); Dhakal, Tara; Ganta, Lakshmikanth; Vanhart, Daniel [Center for Autonomous Solar Power, State University of New York at Binghamton, Binghamton, New York 13902 (United States); Desu, Seshu [State University of New York at Binghamton, Binghamton, New York 13902 (United States)

    2012-12-01

    Zinc sulfide has gained popularity in the last few years as a cadmium-free heterojunction partner for thin film solar cells and is seen as a good replacement for cadmium sulfide due to better blue photon response and non-toxicity. In this work, zinc sulfide films are prepared using an organic sulfur source. We report a simple and repeatable process for development of zinc sulfide using a cost-effective and less hazardous organic sulfur source. The development of zinc sulfide has been studied on zinc oxide-coated glass where the zinc oxide is converted into zinc sulfide. Zinc oxide grown by atomic layer deposition as well as commercially available zinc oxide-coated glass was used. The zinc sulfide synthesis has been studied and the films are characterized using scanning electron microscopy, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and a UV-VIS spectrophotometer. XRD, XPS and optical characterization confirm the zinc sulfide phase formation. - Highlights: Black-Right-Pointing-Pointer Synthesis of ZnS using a less-hazardous precursor, di-tertiary-butyl-disulfide. Black-Right-Pointing-Pointer ZnS process optimized for two types of ZnO films. Black-Right-Pointing-Pointer Preliminary results for a solar cell show an efficiency of 1.09%.

  2. Synthesis of zinc sulfide by chemical vapor deposition using an organometallic precursor: Di-tertiary-butyl-disulfide

    International Nuclear Information System (INIS)

    Zinc sulfide has gained popularity in the last few years as a cadmium-free heterojunction partner for thin film solar cells and is seen as a good replacement for cadmium sulfide due to better blue photon response and non-toxicity. In this work, zinc sulfide films are prepared using an organic sulfur source. We report a simple and repeatable process for development of zinc sulfide using a cost-effective and less hazardous organic sulfur source. The development of zinc sulfide has been studied on zinc oxide-coated glass where the zinc oxide is converted into zinc sulfide. Zinc oxide grown by atomic layer deposition as well as commercially available zinc oxide-coated glass was used. The zinc sulfide synthesis has been studied and the films are characterized using scanning electron microscopy, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and a UV–VIS spectrophotometer. XRD, XPS and optical characterization confirm the zinc sulfide phase formation. - Highlights: ► Synthesis of ZnS using a less-hazardous precursor, di-tertiary-butyl-disulfide. ► ZnS process optimized for two types of ZnO films. ► Preliminary results for a solar cell show an efficiency of 1.09%.

  3. Microbial communities and arsenic biogeochemistry at the outflow of an alkaline sulfide-rich hot spring

    Science.gov (United States)

    Jiang, Zhou; Li, Ping; Van Nostrand, Joy D.; Zhang, Ping; Zhou, Jizhong; Wang, Yanhong; Dai, Xinyue; Zhang, Rui; Jiang, Dawei; Wang, Yanxin

    2016-01-01

    Alkaline sulfide-rich hot springs provide a unique environment for microbial community and arsenic (As) biogeochemistry. In this study, a representative alkaline sulfide-rich hot spring, Zimeiquan in the Tengchong geothermal area, was chosen to study arsenic geochemistry and microbial community using Illumina MiSeq sequencing. Over 0.26 million 16S rRNA sequence reads were obtained from 5-paired parallel water and sediment samples along the hot spring’s outflow channel. High ratios of As(V)/AsSum (total combined arsenate and arsenite concentrations) (0.59–0.78), coupled with high sulfide (up to 5.87 mg/L), were present in the hot spring’s pools, which suggested As(III) oxidation occurred. Along the outflow channel, AsSum increased from 5.45 to 13.86 μmol/L, and the combined sulfide and sulfate concentrations increased from 292.02 to 364.28 μmol/L. These increases were primarily attributed to thioarsenic transformation. Temperature, sulfide, As and dissolved oxygen significantly shaped the microbial communities between not only the pools and downstream samples, but also water and sediment samples. Results implied that the upstream Thermocrinis was responsible for the transformation of thioarsenic to As(III) and the downstream Thermus contributed to derived As(III) oxidation. This study improves our understanding of microbially-mediated As transformation in alkaline sulfide-rich hot springs. PMID:27126380

  4. Microbial communities and arsenic biogeochemistry at the outflow of an alkaline sulfide-rich hot spring

    Science.gov (United States)

    Jiang, Zhou; Li, Ping; van Nostrand, Joy D.; Zhang, Ping; Zhou, Jizhong; Wang, Yanhong; Dai, Xinyue; Zhang, Rui; Jiang, Dawei; Wang, Yanxin

    2016-04-01

    Alkaline sulfide-rich hot springs provide a unique environment for microbial community and arsenic (As) biogeochemistry. In this study, a representative alkaline sulfide-rich hot spring, Zimeiquan in the Tengchong geothermal area, was chosen to study arsenic geochemistry and microbial community using Illumina MiSeq sequencing. Over 0.26 million 16S rRNA sequence reads were obtained from 5-paired parallel water and sediment samples along the hot spring’s outflow channel. High ratios of As(V)/AsSum (total combined arsenate and arsenite concentrations) (0.59–0.78), coupled with high sulfide (up to 5.87 mg/L), were present in the hot spring’s pools, which suggested As(III) oxidation occurred. Along the outflow channel, AsSum increased from 5.45 to 13.86 μmol/L, and the combined sulfide and sulfate concentrations increased from 292.02 to 364.28 μmol/L. These increases were primarily attributed to thioarsenic transformation. Temperature, sulfide, As and dissolved oxygen significantly shaped the microbial communities between not only the pools and downstream samples, but also water and sediment samples. Results implied that the upstream Thermocrinis was responsible for the transformation of thioarsenic to As(III) and the downstream Thermus contributed to derived As(III) oxidation. This study improves our understanding of microbially-mediated As transformation in alkaline sulfide-rich hot springs.

  5. Microbial communities and arsenic biogeochemistry at the outflow of an alkaline sulfide-rich hot spring.

    Science.gov (United States)

    Jiang, Zhou; Li, Ping; Van Nostrand, Joy D; Zhang, Ping; Zhou, Jizhong; Wang, Yanhong; Dai, Xinyue; Zhang, Rui; Jiang, Dawei; Wang, Yanxin

    2016-01-01

    Alkaline sulfide-rich hot springs provide a unique environment for microbial community and arsenic (As) biogeochemistry. In this study, a representative alkaline sulfide-rich hot spring, Zimeiquan in the Tengchong geothermal area, was chosen to study arsenic geochemistry and microbial community using Illumina MiSeq sequencing. Over 0.26 million 16S rRNA sequence reads were obtained from 5-paired parallel water and sediment samples along the hot spring's outflow channel. High ratios of As(V)/AsSum (total combined arsenate and arsenite concentrations) (0.59-0.78), coupled with high sulfide (up to 5.87 mg/L), were present in the hot spring's pools, which suggested As(III) oxidation occurred. Along the outflow channel, AsSum increased from 5.45 to 13.86 μmol/L, and the combined sulfide and sulfate concentrations increased from 292.02 to 364.28 μmol/L. These increases were primarily attributed to thioarsenic transformation. Temperature, sulfide, As and dissolved oxygen significantly shaped the microbial communities between not only the pools and downstream samples, but also water and sediment samples. Results implied that the upstream Thermocrinis was responsible for the transformation of thioarsenic to As(III) and the downstream Thermus contributed to derived As(III) oxidation. This study improves our understanding of microbially-mediated As transformation in alkaline sulfide-rich hot springs. PMID:27126380

  6. Mechanism of mechanical activation for sulfide ores

    Institute of Scientific and Technical Information of China (English)

    HU Hui-ping; CHEN Qi-yuan; YIN Zhou-lan; HE Yue-hui; HUANG Bai-yun

    2007-01-01

    Structural changes for mechanically activated pyrite, sphalerite, galena and molybdenite with or without the exposure to ambient air, were systematically investigated using X-ray diffraction analysis(XRD), particle size analysis, gravimetrical method, X-ray photo-electron spectroscopy(XPS) and scanning electron microscopy(SEM), respectively. Based on the above structural changes for mechanically activated sulfide ores and related reports by other researchers, several qualitative rules of the mechanisms and the effects of mechanical activation for sulfide ores are obtained. For brittle sulfide ores with thermal instability, and incomplete cleavage plane or extremely incomplete cleavage plane, the mechanism of mechanical activation is that a great amount of surface reactive sites are formed during their mechanical activation. The effects of mechanical activation are apparent. For brittle sulfide ores with thermal instability, and complete cleavage plane, the mechanism of mechanical activation is that a great amount of surface reactive sites are formed, and lattice deformation happens during their mechanical activation. The effects of mechanical activation are apparent. For brittle sulfide ores with excellent thermal stability, and complete cleavage plane, the mechanism of mechanical activation is that lattice deformation happens during their mechanical activation. The effects of mechanical activation are apparent. For sulfide ores with high toughness, good thermal stability and very excellent complete cleavage plane, the mechanism of mechanical activation is that lattice deformation happens during their mechanical activation, but the lattice deformation ratio is very small. The effects of mechanical activation are worst.

  7. Is Hydrogen Sulfide-Induced Suspended Animation General Anesthesia?

    OpenAIRE

    Li, Rosie Q.; McKinstry, Andrew R.; Moore, Jason T.; Caltagarone, Breanna M.; Eckenhoff, Maryellen F.; Eckenhoff, Roderic G.; Kelz, Max B.

    2012-01-01

    Hydrogen sulfide (H2S) depresses mitochondrial function and thereby metabolic rates in mice, purportedly resulting in a state of “suspended animation.” Volatile anesthetics also depress mitochondrial function, an effect that may contribute to their anesthetic properties. In this study, we ask whether H2S has general anesthetic properties, and by extension, whether mitochondrial effects underlie the state of anesthesia. We compared loss of righting reflex, electroencephalography, and electromy...

  8. SIP response for volume content of sulfide mineral in artificial specimen

    Science.gov (United States)

    Park, Mi Kyung; Park, Samgyu; Jong Yi, Myeong; Kim, Jung Ho

    2014-05-01

    Spectral Induced Polarization (SIP) method has recently been introduced to enhance mineral resource exploration techniques in metal ore deposit, South Korea. Because the valuable mineral ore contains various sulfide minerals such as pyrite (FeS), chalcopyrite (CuFeS2), and galena (PbS), which show IP (Induced Polarization) effect. The conventional IP method was not adequate to find these various sulfide minerals because of certain restrictions, including limited frequency. In order to solve this problem, the SIP (Spectral Induced Polarization) method was introduced, which measures responses like as amplitude (or resistivity) and phase for a wide frequency band. The application of the SIP method has been increasing as an exploration technology for mineral resources, because it can be used to acquire and analyze high quality IP data according to the spectral frequency. SIP responses are strong in the presence of the sulfide minerals; however, sufficient study on the characteristics of the SIP response for the various sulfide minerals is not available so far. In this study, in order to identify the SIP response characteristics of sulfide minerals, the SIP method was used in the laboratory; on artificial specimens filled with glass beads and sulfide minerals. The experiment was controlled by the changing volume content, and grain size, of three kinds of sulfide minerals (i.e., chalcopyrite, pyrite, and galena). The grain sizes of the sulfide minerals were varied in five steps: under 0.5 mm, 0.5 - 1.0 mm, 1.0 - 2.0 mm, 2.0 - 2.85 mm, and 2.85 - 4.0 mm, while the grain size of the glass beads was in the range of 0.75 - 1.0 mm. Variation of the volume content of the sulfide mineral was divided into eight grades. The sulfide minerals occupied 0.5, 1, 2, 3, 5, 7, 10, and 20 percent of the total volume 250 ml specimens. The volume content was converted from the weight using the density of a standard volume of 100 ml for each grain size. The results show that phase response

  9. Organoselenium-catalyzed, hydroxy-controlled regio- and stereoselective amination of terminal alkenes: efficient synthesis of 3-amino allylic alcohols.

    Science.gov (United States)

    Deng, Zhimin; Wei, Jialiang; Liao, Lihao; Huang, Haiyan; Zhao, Xiaodan

    2015-04-17

    An efficient route to prepare 3-amino allylic alcohols in excellent regio- and stereoselectivity in the presence of bases by orangoselenium catalysis has been developed. In the absence of bases α,β-unsaturated aldehydes were formed in up to 97% yield. Control experiments reveal that the hydroxy group is crucial for the direct amination. PMID:25849818

  10. Mechanistic Dichotomy in the Asymmetric Allylation of Aldehydes with Allyltrichlorosilanes Catalyzed by Chiral Pyridine N-Oxides

    Czech Academy of Sciences Publication Activity Database

    Malkov, A. V.; Stončius, S.; Bell, M.; Castelluzzo, F.; Ramírez-López, P.; Biedermannová, Lada; Langer, V.; Rulíšek, Lubomír; Kočovský, P.

    2013-01-01

    Roč. 19, č. 28 (2013), s. 9167-9185. ISSN 0947-6539 R&D Projects: GA MŠk LC512 Institutional support: RVO:61388963 ; RVO:86652036 Keywords : allylation * allylsilanes * calculations * organocatalysis * pyridine N-oxides Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 5.696, year: 2013

  11. Synthesis of novel chiral phosphine-triazine ligand derived from α-phenylethylamine for Pd-catalyzed asymmetric allylic alkylation

    Institute of Scientific and Technical Information of China (English)

    Jia Di Huang; Xiang Ping Hu; Zhuo Zheng

    2008-01-01

    A novel chiral phosphine-triazine ligand was synthesized from chiral model reaction of Pd-catalyzed allylic alkylation of rac-l,3-diphenylprop-2-en-l-yl pivalate with dimethyl malonate, good enantioselectivity (90% e.e.) was obtained by using this ligand.

  12. Growth behavior prediction of fresh catfish fillet with Pseudomonas aeruginosa under stresses of allyl isothiocyanate, temperature and modified atmosphere

    Science.gov (United States)

    Pseudomonas aeruginosa, a common spoilage microorganism in fish, grows rapidly when temperature rises above 4 degree C. The combination of allyl isothiocyanate (AIT) and modified atmosphere (MA) was applied and proved to be effective to retard the growth of P. aeruginosa. The objective of this resea...

  13. Aldehyde Selective Wacker Oxidations of Phthalimide Protected Allylic Amines : A New Catalytic Route to beta(3)-Amino Acids

    NARCIS (Netherlands)

    Weiner, Barbara; Baeza Garcia, Alejandro; Jerphagnon, Thomas; Feringa, Ben L.

    2009-01-01

    A new method for the synthesis of B-3-amino acids is presented. Phthalimide protected allylic amines are oxidized under Wacker conditions selectively to aldehydes using PdCl2 and CuCl or Pd(MeCN)(2)Cl(NO2) and CuCl2 as complementary catalyst systems. The aldehydes are produced in excellent yields an

  14. Time-resolved fluorescence sensing of pesticides chlorpyrifos, crotoxyphos and endosulfan by the luminescent Eu(III)-8-allyl-3-carboxycoumarin probe

    Science.gov (United States)

    Azab, Hassan A.; Khairy, Gasser M.; Kamel, Rasha M.

    2015-09-01

    This work describes the application of time resolved fluorescence in microtiter plates for investigating the interactions of europium-allyl-3-carboxycoumarin with pesticides chlorpyrifos, endosulfan and crotoxyphos. Stern-Volmer studies at different temperatures for chlorpyrifos and crotoxyphos shows dynamic and static quenching mechanisms respectively. Direct methods for the determination of the pesticides under investigation have been developed using the luminescence variations of the probe in solution. The detection limits are 6.53, 0.004, 3.72 μmol/L for chlorpyrifos, endosulfan, and crotoxyphos, respectively. The binding constants and thermodynamic parameters of the pesticides with probe were evaluated. A thermodynamic analysis showed that the reaction is spontaneous with negative ΔG. Effect of some relevant interferents on the detection of pesticides has been investigated. The new method was applied to the determination of the pesticides in different types of water samples (tap, mineral, and waste water).

  15. Sulfide response analysis for sulfide control using a pS electrode in sulfate reducing bioreactors.

    Science.gov (United States)

    Villa-Gomez, D K; Cassidy, J; Keesman, K J; Sampaio, R; Lens, P N L

    2014-03-01

    Step changes in the organic loading rate (OLR) through variations in the influent chemical oxygen demand (CODin) concentration or in the hydraulic retention time (HRT) at constant COD/SO4(2-) ratio (0.67) were applied to create sulfide responses for the design of a sulfide control in sulfate reducing bioreactors. The sulfide was measured using a sulfide ion selective electrode (pS) and the values obtained were used to calculate proportional-integral-derivative (PID) controller parameters. The experiments were performed in an inverse fluidized bed bioreactor with automated operation using the LabVIEW software version 2009(®). A rapid response and high sulfide increment was obtained through a stepwise increase in the CODin concentration, while a stepwise decrease to the HRT exhibited a slower response with smaller sulfide increment. Irrespective of the way the OLR was decreased, the pS response showed a time-varying behavior due to sulfide accumulation (HRT change) or utilization of substrate sources that were not accounted for (CODin change). The pS electrode response, however, showed to be informative for applications in sulfate reducing bioreactors. Nevertheless, the recorded pS values need to be corrected for pH variations and high sulfide concentrations (>200 mg/L). PMID:24361702

  16. Sulfide-driven autotrophic denitrification significantly reduces N2O emissions.

    Science.gov (United States)

    Yang, Weiming; Zhao, Qing; Lu, Hui; Ding, Zhi; Meng, Liao; Chen, Guang-Hao

    2016-03-01

    The Sulfate reduction-Autotrophic denitrification-Nitrification Integrated (SANI) process build on anaerobic carbon conversion through biological sulfate reduction and autotrophic denitrification by using the sulfide byproduct from the previous reaction. This study confirmed extra decreases in N2O emissions from the sulfide-driven autotrophic denitrification by investigating N2O reduction, accumulation, and emission in the presence of different sulfide/nitrate (S/N) mass ratios at pH 7 in a long-term laboratory-scale granular sludge autotrophic denitrification reactor. The N2O reduction rate was linearly proportional to the sulfide concentration, which confirmed that no sulfide inhibition of N2O reductase occurred. At S/N = 5.0 g-S/g-N, this rate resulted by sulfide-driven autotrophic denitrifying granular sludge (average granule size = 701 μm) was 27.7 mg-N/g-VSS/h (i.e., 2 and 4 times greater than those at 2.5 and 0.8 g-S/g-N, respectively). Sulfide actually stimulates rather than inhibits N2O reduction no matter what granule size of sulfide-driven autotrophic denitrifying sludge engaged. The accumulations of N2O, nitrite and free nitrous acid (FNA) with average granule size 701 μm of sulfide-driven autotrophic denitrifying granular sludge engaged at S/N = 5.0 g-S/g-N were 4.7%, 11.4% and 4.2% relative to those at 3.0 g-S/g-N, respectively. The accumulation of FNA can inhibit N2O reduction and increase N2O accumulation during sulfide-driven autotrophic denitrification. In addition, the N2O gas emission level from the reactor significantly increased from 14.1 ± 0.5 ppmv (0.002% of the N load) to 3707.4 ± 36.7 ppmv (0.405% of the N load) as the S/N mass ratio in the influent decreased from 2.1 to 1.4 g-S/g-N over the course of the 120-day continuous monitoring period. Sulfide-driven autotrophic denitrification may significantly reduce greenhouse gas emissions from biological nutrient removal when sulfur conversion processes are applied. PMID

  17. Ab Initio Investigation of Methanthiol and Dimethyl Sulfide Adsorption on Zeolite

    Institute of Scientific and Technical Information of China (English)

    Lü Renqing

    2006-01-01

    The Hartree-Fock and cluster model methods have been employed to investigate interactions of methanthiol or dimethyl sulfide on zeolites. Molecular complexes formed by adsorption of methanthiol on silanol H3SiOSi(OH)2OSiH3 with five coordination forms and dimethyl sulfide on silanol H3SiOSi(OH)2OSiH3 with four coordination forms, and Br(o)nsted acid sites of bridging hydroxyl H3Si(OH)Al(OH)2OSiH3 entering into interactions with methanthiol or dimethyl sulfide have been investigated. Full optimization and frequency analysis of all cluster models have been carried out using the Hartree-Fock method at 6-31 +G** basis set level for hydrogen, silicon, aluminum, oxygen, carbon, and sulfur atoms. The structures and energy changes of different coordination forms derived from methanthiol and H3Si(OH)Al(OH)2OSiH3, dimethyl sulfide and H3Si(OH)Al(OH)2OSiH3, methanthiol and H3SiOSi(OH)2OSiH3, dimethyl sulfide and H3SiOSi(OH)2OSiH3 complexes have been comparatively studied. The calculated results showed that the nature of interactions leading to the formation of the bridging hydroxyl-methanthiol, silanol-methanthiol,bridging hydroxyl-dimethyl sulfide, silanol-dimethyl sulfide complexes was governed by the Van der Waals force as confirmed by a small change in geometric structures and properties. Methanthiol and dimethyl sulfide molecules were adsorbed on bridging hydroxyl group prior to silanol group as evidenced by the heat of adsorption, and the protonization of methanthiol adsorption on bridging hydroxyl model, which was supposed in the literature, was not found.

  18. Study on the Dealing and Controlling Measures of Hydrogen Sulfide in High 95 Well%高95井硫化氢处理及防治措施研究

    Institute of Scientific and Technical Information of China (English)

    谢立志; 张磊; 顾晓强; 赵荣

    2012-01-01

    This article analyzes and concludes the influence of hydrogen sulfide on the drilling and the precautions for the drilling.Main controlling measures are proposed for the six-time highly displayed hydrogen sulfide in the core drilling process of the high 95 well in Shengli Oilfield,which is highly relevant to the wells of mass hydrogen sulfide in the block.%文章分析总结了硫化氢对钻井的影响及在钻井中应注意的事项,并结合胜利油田高95井现场取芯钻井过程中硫化氢六次高显示的处理工艺,提出了主要防治措施,对该区块的高含硫化氢井有参考借鉴价值.

  19. Simultaneous removal of sulfide, nitrate and acetate under denitrifying sulfide removal condition: Modeling and experimental validation

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Xijun; Chen, Chuan; Wang, Aijie; Guo, Wanqian; Zhou, Xu [State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090 (China); Lee, Duu-Jong, E-mail: djlee@ntu.edu.tw [State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090 (China); Department of Chemical Engineering, National Taiwan University, Taipei 106, Taiwan (China); Department of Chemical Engineering, National Taiwan University of Science and Technology, Taipei 106, Taiwan (China); Ren, Nanqi, E-mail: rnq@hit.edu.cn [State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090 (China); Chang, Jo-Shu [Research Center for Energy Technology and Strategy, National Cheng Kung University, Tainan, Taiwan (China)

    2014-01-15

    Graphical abstract: Model evaluation applied to case study 1: (A-G) S{sup 2−}, NO{sub 3}{sup −}-N, NO{sub 2}{sup −}-N, and Ac{sup −}-C profiles under initial sulfide concentrations of 156.2 (A), 539 (B), 964 (C), 1490 (D), 342.7 (E), 718 (F), and 1140.7 (G) mg L{sup −1}. The solid line represents simulated result and scatter represents experimental result. -- Highlights: • This work developed a mathematical model for DSR process. • Kinetics of sulfur–nitrogen–carbon and interactions between denitrifiers were studied. • Kinetic parameters of the model were estimated via data fitting. • The model described kinetic behaviors of DSR processes over wide parametric range. -- Abstract: Simultaneous removal of sulfide (S{sup 2−}), nitrate (NO{sub 3}{sup −}) and acetate (Ac{sup −}) under denitrifying sulfide removal process (DSR) is a novel biological wastewater treatment process. This work developed a mathematical model to describe the kinetic behavior of sulfur–nitrogen–carbon and interactions between autotrophic denitrifiers and heterotrophic denitrifiers. The kinetic parameters of the model were estimated via data fitting considering the effects of initial S{sup 2−} concentration, S{sup 2−}/NO{sub 3}{sup −}-N ratio and Ac{sup −}-C/NO{sub 3}{sup −}-N ratio. Simulation supported that the heterotrophic denitratation step (NO{sub 3}{sup −} reduction to NO{sub 2}{sup −}) was inhibited by S{sup 2−} compared with the denitritation step (NO{sub 2}{sup −} reduction to N{sub 2}). Also, the S{sup 2−} oxidation by autotrophic denitrifiers was shown two times lower in rate with NO{sub 2}{sup −} as electron acceptor than that with NO{sub 3}{sup −} as electron acceptor. NO{sub 3}{sup −} reduction by autotrophic denitrifiers occurs 3–10 times slower when S{sup 0} participates as final electron donor compared to the S{sup 2−}-driven pathway. Model simulation on continuous-flow DSR reactor suggested that the adjustment of

  20. Activity Variation of Phanerochaete chrysosporium under Nanosilver Exposure by Controlling of Different Sulfide Sources

    Science.gov (United States)

    Guo, Zhi; Chen, Guiqiu; Liu, Lingzhi; Zeng, Guangming; Huang, Zhenzhen; Chen, Anwei; Hu, Liang

    2016-02-01

    Due to the particular activation and inhibition behavior of silver nanoparticles (AgNPs) on microbes at various concentrations, it’s crucial to exploit the special concentration effect in environment. Here, we studied the viability variation of Phanerochaete chrysosporium (P. chrysosporium) under exposure to citrate-coated AgNPs (Citrate-AgNPs) in the presence of different sulfide sources (an inorganic sulfide, NaHS and an organic sulfide, thioacetamide (TAA)). The results indicated that both NaHS and TAA can promote activation of P. chrysosporium by Citrate-AgNPs at a higher concentration, which was initial at toxic level. Treatment with various concentrations of Citrate-AgNPs (0-9 mg/L) demonstrated a maximum activation concentration (MAC) at 3 mg/L. With the increase in sulfide concentration, MAC transferred to higher concentration significantly, indicating the obvious “toxicity to activation” transformation at a higher concentration. Ag+ testing exhibited that variations in sulfide-induced Ag+ concentration (3-7 μg/L Ag+) accounted for the “toxicity to activation” transformation. In addition, the similar results were observed on antibacterial application using Escherichia coli as the model species. Based on the research results, the application of this transformation in improving antibacterial activity was proposed. Therefore, the antibacterial activity of AgNPs can be controlled, even at concentration, via adjusting for the sulfide concentration.

  1. Investigation of the Electrocatalytic Activity of Rhodium Sulfide for Hydrogen Evolution and Hydrogen Oxidation

    International Nuclear Information System (INIS)

    We report the synthesis of unsupported and carbon-supported, mixed phase, rhodium sulfide, using both a hydrogen sulfide source and a solid sulfur source. Samples with several different distributions of rhodium sulfide phases (Rh2S3, Rh17S15, RhS2 and metallic Rh) were obtained by varying the temperature and exposure time to H2S or sulfur to rhodium ratio when using solid sulfur. Samples were characterized by X-ray diffraction (XRD), and the unsupported rhodium sulfide compounds studied using Raman spectroscopy to link Raman spectra to catalyst phases. The electrocatalytic activity of the rhodium sulfide compounds for hydrogen evolution and oxidation was measured using rotating disk electrode measurements in acidic conditions to simulate use in a flow cell. The most active phases for hydrogen evolution were found to be Rh3S4 and Rh17S15 (−0.34 V vs. Ag/AgCl required for 20 mA/cm2), while Rh2S3 and RhS2 phases were relatively inactive (−0.46 V vs. Ag/AgCl required for 20 mA/cm2 using RhS2/C). The hydrogen oxidation activity of all rhodium sulfide phases is significantly lower than the hydrogen evolution activity and is not associated with conductivity limitations

  2. Discrimination among iron sulfide species formed in microbial cultures.

    Science.gov (United States)

    Popa, R; Kinkle, B K

    2000-10-01

    A quantitative method for the study of iron sulfides precipitated in liquid cultures of bacteria is described. This method can be used to quantify and discriminate among amorphous iron sulfide (FeS(amorph)), iron monosulfide minerals such as mackinawite or greigite (FeS(min)), and iron disulfide minerals such as pyrite or marcasite (FeS(2min)) formed in liquid cultures. Degradation of iron sulfides is performed using a modified Cr(2+) reduction method with reflux distillation. The basic steps of the method are: first, separation of FeS(amorph); second, elimination of interfering species of S such as colloidal sulfur (S(c) degrees ), thiosulphate (S(2)O(3)(2-)) and polysulfides (S(x)(2-)); third, separation of FeS(min); and fourth, separation of FeS(2min). The final product is H(2)S which is determined after trapping. The efficiency of recovery is 96-99% for FeS(amorph), 76-88% for FeS(min), and >97% for FeS(2min). This method has a high reproducibility if the experimental conditions are rigorously applied and only glass conduits are used. A well ventilated fume hood must be used because of the toxicity and volatility of several reagents and products. The advantage relative to previously described methods are better resolution for iron sulfide species and use of the same bottles for both incubation of cultures and acid degradation. The method can also be used for Fe/S stoichiometry with sub-sampling and Fe analysis. PMID:11018273

  3. Hydrogen Sulfide and Urogenital Tract.

    Science.gov (United States)

    di Villa Bianca, Roberta d'Emmanuele; Cirino, Giuseppe; Sorrentino, Raffaella

    2015-01-01

    In this chapter the role played by H2S in the physiopathology of urogenital tract revising animal and human data available in the current relevant literature is discussed. H2S pathway has been demonstrated to be involved in the mechanism underlying penile erection in human and experimental animal. Both cystathionine-β synthase (CBS) and cystathionine-γ lyase (CSE) are expressed in the human corpus cavernosum and exogenous H2S relaxes isolated human corpus cavernosum strips in an endothelium-independent manner. Hydrogen sulfide pathway also accounts for the direct vasodilatory effect operated by testosterone on isolated vessels. Convincing evidence suggests that H2S can influence the cGMP pathway by inhibiting the phosphodiesterase 5 (PDE-5) activity. All these findings taken together suggest an important role for the H2S pathway in human corpus cavernosum homeostasis. However, H2S effect is not confined to human corpus cavernosum but also plays an important role in human bladder. Human bladder expresses mainly CBS and generates in vitro detectable amount of H2S. In addition the bladder relaxant effect of the PDE-5 inhibitor sildenafil involves H2S as mediator. In conclusion the H2S pathway is not only involved in penile erection but also plays a role in bladder homeostasis. In addition the finding that it involved in the mechanism of action of PDE-5 inhibitors strongly suggests that modulation of this pathway can represent a therapeutic target for the treatment of erectile dysfunction and bladder diseases. PMID:26162831

  4. Terahertz spectroscopy of hydrogen sulfide

    International Nuclear Information System (INIS)

    Pure rotational transitions of hydrogen sulfide (H2S) in its ground and first excited vibrational states have been recorded at room temperature. The spectrum comprises an average of 1020 scans at 0.005 cm−1 resolution recorded in the region 45–360 cm−1 (1.4 to 10.5 THz) with a globar continuum source using a Fourier transform spectrometer located at the AILES beamline of the SOLEIL synchrotron. Over 2400 rotational lines have been detected belonging to ground vibrational state transitions of the four isotopologues H232S, H233S, H234S, and H236S observed in natural abundance. 65% of these lines are recorded and assigned for the first time, sampling levels as high as J=26 and Ka=17 for H232S. 320 pure rotational transitions of H232S in its first excited bending vibrational state are recorded and analysed for the first time and 86 transitions for H234S, where some of these transitions belong to new experimental energy levels. Rotational constants have been fitted for all the isotopologues in both vibrational states using a standard effective Hamiltonian approach. Comprehensive comparisons are made with previously available data as well as the data available in HITRAN, CDMS, and JPL databases. The 91 transitions assigned to H236S give the first proper characterization of its pure rotational spectrum. -- Highlights: • Over 2400 lines are measured and assigned in the 45–360 cm−1 region. • New rotational transitions are assigned for four isotopologues of H2S. • Rotational transitions within the first excited state of H2S are assigned for the first time. • An improved rotational line list is presented

  5. Enantioselective construction of quaternary N-heterocycles by palladium-catalysed decarboxylative allylic alkylation of lactams

    KAUST Repository

    Behenna, Douglas C.

    2011-12-18

    The enantioselective synthesis of nitrogen-containing heterocycles (N-heterocycles) represents a substantial chemical research effort and resonates across numerous disciplines, including the total synthesis of natural products and medicinal chemistry. In this Article, we describe the highly enantioselective palladium-catalysed decarboxylative allylic alkylation of readily available lactams to form 3,3-disubstituted pyrrolidinones, piperidinones, caprolactams and structurally related lactams. Given the prevalence of quaternary N-heterocycles in biologically active alkaloids and pharmaceutical agents, we envisage that our method will provide a synthetic entry into the de novo asymmetric synthesis of such structures. As an entry for these investigations we demonstrate how the described catalysis affords enantiopure quaternary lactams that intercept synthetic intermediates previously used in the synthesis of the Aspidosperma alkaloids quebrachamine and rhazinilam, but that were previously only available by chiral auxiliary approaches or as racemic mixtures. © 2012 Macmillan Publishers Limited. All rights reserved.

  6. On the allylic hydroxylation of ent-kaurenic acid with SeO2

    Directory of Open Access Journals (Sweden)

    Alexis Peña

    2014-12-01

    Full Text Available Allylic hydroxylation of ent-kaur-16-en-19-oic acid (1a with SeO2 was tried using either dioxane or dichloro-methane as solvents as well as different reagent and reaction time conditions at room temperature. Oxidation of 1a in dioxane with H2O2 decreased reaction time but led to the formation of many by-products on addition to ent-15D-hydroxy-kaur-16-en-19-oic acid (2a, which was the main product. Using dichloromethane as solvent without addition of H2O2 made the reaction slower and yielded mainly 2a (70% at 24 h, 53% at 48 h and ent-17-oxo-kaur- 15,16-en-19-oic acid (3a,18% at 24 h, 43% at 48 h. The course of the reaction was followed by GC-MS, after methylation of the reaction mixtures.

  7. The Effect of Allylic Sulfide-Mediated IrreversibleAddition-Fragment Chain Transfer on the EmulsionPolymerization Kinetics of Styrene

    Directory of Open Access Journals (Sweden)

    Li An

    2015-09-01

    Full Text Available The effect of the irreversible addition-fragment chain transfer agent, butyl(2-phenylallylsulfane (BPAS, on the course of the emulsion polymerization of styrene and on the product molecular weight was investigated. The emulsion polymerizations were performed using various amounts of sodium dodecyl sulfate (SDS as the surfactant and potassium peroxodisulfate (KPS as the initiator. The relationships between the rates of polymerization (\\(R_{p} \\ and the number of particles per volume (\\(N_{c} \\ with respect to the concentrations of KPS, SDS, and BPAS were found to be \\(R_{p} \\propto \\left\\lbrack KPS \\right\\rbrack^{0.29} \\, \\(N_{c} \\propto \\left\\lbrack KPS \\right\\rbrack^{0.26} \\,\\(R_{p} \\propto \\left\\lbrack SDS \\right\\rbrack^{0.68} \\, \\(N_{c} \\propto \\left\\lbrack SDS \\right\\rbrack^{0.72} \\, and \\(R_{p} \\propto \\left\\lbrack BPAS \\right\\rbrack^{- 0.73} \\ . The obtained relationships can be attributed to the exit of the leaving group radicals on BPAS from the polymer particles. The experimental values of the average number of radicals per particle (\\(\\overset{\\_}{n} \\ were strongly dependent on the BPAS concentration and were in good agreement with the theoretical values (\\({\\overset{\\_}{n}}_{theo} \\ from model calculations. The number-average molecular weight (\\(\\overset{\\_}{M_{n}} \\ can be controlled by BPAS over nearly the entire conversion range, which is also in agreement with the mathematical model. In addition, the transfer rate coefficient (\\(k_{tr} \\ of BPAS can be estimated as 326 L/mol/s at 70 \\(^\\circ\\C. Moreover, similar good results were found for the tested redox reactions at 30 \\(^\\circ\\C.

  8. Effect of allyl alcohol on hepatic transporter expression: Zonal patterns of expression and role of Kupffer cell function

    International Nuclear Information System (INIS)

    During APAP toxicity, activation of Kupffer cells is critical for protection from hepatotoxicity and up-regulation of multidrug resistance-associated protein 4 (Mrp4) in centrilobular hepatocytes. The present study was performed to determine the expression profile of uptake and efflux transporters in mouse liver following treatment with allyl alcohol (AlOH), a periportal hepatotoxicant. This study also investigated the role of Kupffer cells in AlOH hepatotoxicity, and whether changes in transport protein expression by AlOH are dependent on the presence of Kupffer cells. C57BL/6J mice received 0.1 ml clodronate liposomes to deplete Kupffer cells or empty liposomes 48 h prior to dosing with 60 mg/kg AlOH, i.p. Hepatotoxicity was assessed by plasma ALT and histopathology. Hepatic transporter mRNA and protein expression were determined by branched DNA signal amplification assay and Western blotting, respectively. Depletion of Kupffer cells by liposomal clodronate treatment resulted in heightened susceptibility to AlOH toxicity. Exposure to AlOH increased mRNA levels of several Mrp genes, while decreasing organic anion transporting polypeptides (Oatps) mRNA expression. Protein analysis mirrored many of these mRNA changes. The presence of Kupffer cells was not required for the observed changes in uptake and efflux transporters induced by AlOH. Immunofluorescent analysis revealed enhanced Mrp4 staining exclusively in centrilobular hepatocytes of AlOH treated mice. These findings demonstrate that Kupffer cells are protective from AlOH toxicity and that induction of Mrp4 occurs in liver regions away from areas of AlOH damage independent of Kupffer cell function. These results suggest that Kupffer cell mediators do not play a role in mediating centrilobular Mrp4 induction in response to periportal damage by AlOH

  9. Effect of allyl alcohol on hepatic transporter expression: Zonal patterns of expression and role of Kupffer cell function

    Science.gov (United States)

    Campion, Sarah N.; Tatis-Rios, Cristina; Augustine, Lisa M.; Goedken, Michael J.; van Rooijen, Nico; Cherrington, Nathan J.; Manautou, José E.

    2015-01-01

    During APAP toxicity, activation of Kupffer cells is critical for protection from hepatotoxicity and up-regulation of multidrug resistance-associated protein 4 (Mrp4) in centrilobular hepatocytes. The present study was performed to determine the expression profile of uptake and efflux transporters in mouse liver following treatment with allyl alcohol (AlOH), a periportal hepatotoxicant. This study also investigated the role of Kupffer cells in AlOH hepatotoxicity, and whether changes in transport protein expression by AlOH are dependent on the presence of Kupffer cells. C57BL/6J mice received 0.1 ml clodronate liposomes to deplete Kupffer cells or empty liposomes 48 h prior to dosing with 60 mg/kg AlOH, i.p. Hepatotoxicity was assessed by plasma ALT and histopathology. Hepatic transporter mRNA and protein expression were determined by branched DNA signal amplification assay and Western blotting, respectively. Depletion of Kupffer cells by liposomal clodronate treatment resulted in heightened susceptibility to AlOH toxicity. Exposure to AlOH increased mRNA levels of several Mrp genes, while decreasing organic anion transporting polypeptides (Oatps) mRNA expression. Protein analysis mirrored many of these mRNA changes. The presence of Kupffer cells was not required for the observed changes in uptake and efflux transporters induced by AlOH. Immunofluorescent analysis revealed enhanced Mrp4 staining exclusively in centrilobular hepatocytes of AlOH treated mice. These findings demonstrate that Kupffer cells are protective from AlOH toxicity and that induction of Mrp4 occurs in liver regions away from areas of AlOH damage independent of Kupffer cell function. These results suggest that Kupffer cell mediators do not play a role in mediating centrilobular Mrp4 induction in response to periportal damage by AlOH. PMID:19371622

  10. Hydrogen sulfide monitoring and the effects of oil and gas activities on migratory birds in southeastern New Mexico [draft

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This study examined the effects of hydrogen sulfide H2S, emitted by oil and gas activities, by focusing on migratory birds in southeastern New Mexico. Study sites...

  11. Hydrogen Sulfide and Endothelium-Dependent Vasorelaxation

    Directory of Open Access Journals (Sweden)

    Jerzy Bełtowski

    2014-12-01

    Full Text Available In addition to nitric oxide and carbon monoxide, hydrogen sulfide (H2S, synthesized enzymatically from l-cysteine or l-homocysteine, is the third gasotransmitter in mammals. Endogenous H2S is involved in the regulation of many physiological processes, including vascular tone. Although initially it was suggested that in the vascular wall H2S is synthesized only by smooth muscle cells and relaxes them by activating ATP-sensitive potassium channels, more recent studies indicate that H2S is synthesized in endothelial cells as well. Endothelial H2S production is stimulated by many factors, including acetylcholine, shear stress, adipose tissue hormone leptin, estrogens and plant flavonoids. In some vascular preparations H2S plays a role of endothelium-derived hyperpolarizing factor by activating small and intermediate-conductance calcium-activated potassium channels. Endothelial H2S signaling is up-regulated in some pathologies, such as obesity and cerebral ischemia-reperfusion. In addition, H2S activates endothelial NO synthase and inhibits cGMP degradation by phosphodiesterase 5 thus potentiating the effect of NO-cGMP pathway. Moreover, H2S-derived polysulfides directly activate protein kinase G. Finally, H2S interacts with NO to form nitroxyl (HNO—a potent vasorelaxant. H2S appears to play an important and multidimensional role in endothelium-dependent vasorelaxation.

  12. Functional consortium for denitrifying sulfide removal process

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Chuan [Harbin Inst. of Technology (CN). State Key Lab. of Water Resource and Environment (SKLWRE); Harbin Inst. of Technology (China). School of Municipal and Environmental Engineering; Ren, Nanqi; Wang, Aijie [Harbin Inst. of Technology (CN). State Key Lab. of Water Resource and Environment (SKLWRE); Liu, Lihong [Harbin Inst. of Technology (China). School of Municipal and Environmental Engineering; Lee, Duu-Jong [Harbin Inst. of Technology (CN). State Key Lab. of Water Resource and Environment (SKLWRE); National Taiwan Univ., Taipei (China). Dept. of Chemical Engineering

    2010-03-15

    Denitrifying sulfide removal (DSR) process simultaneously converts sulfide, nitrate, and chemical oxygen demand from industrial wastewaters to elemental sulfur, nitrogen gas, and carbon dioxide, respectively. This investigation utilizes a dilution-to-extinction approach at 10{sup -2} to 10{sup -6} dilutions to elucidate the correlation between the composition of the microbial community and the DSR performance. In the original suspension and in 10{sup -2} dilution, the strains Stenotrophomonas sp., Thauera sp., and Azoarcus sp. are the heterotrophic denitrifiers and the strains Paracoccus sp. and Pseudomonas sp. are the sulfide-oxidizing denitrifers. The 10{sup -4} dilution is identified as the functional consortium for the present DSR system, which comprises two functional strains, Stenotrophomonas sp. strain Paracoccus sp. At 10{sup -6} dilution, all DSR performance was lost. The functions of the constituent cells in the DSR granules were discussed based on data obtained using the dilution-to-extinction approach. (orig.)

  13. Transition Metal Catalyzed Synthesis of Aryl Sulfides

    Directory of Open Access Journals (Sweden)

    Chad C. Eichman

    2011-01-01

    Full Text Available The presence of aryl sulfides in biologically active compounds has resulted in the development of new methods to form carbon-sulfur bonds. The synthesis of aryl sulfides via metal catalysis has significantly increased in recent years. Historically, thiolates and sulfides have been thought to plague catalyst activity in the presence of transition metals. Indeed, strong coordination of thiolates and thioethers to transition metals can often hinder catalytic activity; however, various catalysts are able to withstand catalyst deactivation and form aryl carbon-sulfur bonds in high-yielding transformations. This review discusses the metal-catalyzed arylation of thiols and the use of disulfides as metal-thiolate precursors for the formation of C-S bonds.

  14. Solar thermal extraction of copper from sulfides

    Energy Technology Data Exchange (ETDEWEB)

    Winkel, L.; Guesdon, C.; Sturzenegger, M.

    2003-03-01

    With the aim to develop a solar-driven process for the extraction of copper from sulfide concentrates re-search on the decomposition of copper sulfides under inert atmospheres has been initiated. Thermogravimetric measurements on chalcocite (Cu{sub 2}S) revealed that copper is formed already at 1823 K. Chalcopyrite (CuFeS{sub 2}) also disintegrates at this temperature, although at a lower rate. Copper and iron have been identified in the solid residue. The results confirm the feasibility of copper extraction by direct decomposition of sulfides under atmospheric pressure. The decomposition under inert atmosphere prevents generation of SO{sub 2}, and is beneficial to the removal of volatile impurities. Chemical equilibrium calculations for CuFeS{sub 2} contaminated with enargite (Cu{sub 3}AsS{sub 4}) have shown that the absence of an oxidic slag allows for a complete evaporation of arsenic and subsequent separation. (author)

  15. Iron-sulfide crystals in probe deposits

    DEFF Research Database (Denmark)

    Laursen, Karin; Frandsen, Flemming

    1998-01-01

    Iron-sulfides were observed in deposits collected on a probe inserted at the top of the furnace of a coal-fired power station in Denmark. The chemical composition of the iron-sulfides is equivalent to pyrrhotite (FeS). The pyrrhotites are present as crystals and, based on the shape of the crystals......, it was deduced that they were not deposited but instead grew within the deposit. The presence of unburned char particles within the deposits supports the concept that a reducing environment existed in the deposits. Two processes are proposed for explaining the existence of pyrrhotite crystals within...... a deposit: (1) impact of low viscous droplets of iron sulfide; and (2) sulfur diffusion. Previous research on the influence of pyrite on slagging focused on the decomposition of pyrite into pyrrhotite and especially on the oxidation stage of this product during impact on the heat transfer surfaces...

  16. Inhibition of Listeria monocytogenes on cooked cured chicken breasts by acidified coating containing allyl isothiocyanate or deodorized Oriental mustard extract.

    Science.gov (United States)

    Olaimat, Amin N; Holley, Richard A

    2016-08-01

    Ready-to-eat meats are considered foods at high risk to cause life-threatening Listeria monocytogenes infections. This study screened 5 L. monocytogenes strains for their ability to hydrolyze sinigrin (a glucosinolate in Oriental mustard), which formed allyl isothiocyanate (AITC) and reduced L. monocytogenes viability on inoculated vacuum-packed, cooked, cured roast chicken slices at 4 °C. Tests involved incorporation of 25-50 μl/g AITC directly or 100-250 mg/g Oriental mustard extract in 0.5% (w/v) κ-carrageenan/2% (w/v) chitosan-based coatings prepared using 1.5% malic or acetic acid. L. monocytogenes strains hydrolyzed 33.6%-48.4% pure sinigrin in MH broth by 21 d at 25 °C. Acidified κ-carrageenan/chitosan coatings containing 25-50 μl/g AITC or 100-250 mg/g mustard reduced the viability of L. monocytogenes and aerobic bacteria on cooked, cured roast chicken slices by 4.1 to >7.0 log10 CFU/g compared to uncoated chicken stored at 4 °C for 70 d. Coatings containing malic acid were significantly more antimicrobial than those with acetic acid. During storage for 70 d, acidified κ-carrageenan/chitosan coatings containing 25-50 μl/g AITC or 250 mg/g mustard extract reduced lactic acid bacteria (LAB) numbers 3.8 to 5.4 log10 CFU/g on chicken slices compared to uncoated samples. Acidified κ-carrageenan/chitosan-based coatings containing either AITC or Oriental mustard extract at the concentrations tested had the ability to control L. monocytogenes viability and delay growth of potential spoilage bacteria on refrigerated, vacuum-packed cured roast chicken. PMID:27052706

  17. 肝脏缺血再灌注损伤中硫化氢的作用新研究%To Study the Role of Hydrogen Sulfide in the Injury of Hepatic Ischemia Reperfusion

    Institute of Scientific and Technical Information of China (English)

    王佩; 王与胜

    2015-01-01

    肝脏缺血再灌注(hepatic ischemia reperfusion,HIRI)会对肝功能造成严重损伤,尤其是当患有肝硬化时,风险便会加剧。合理剂量的硫化氢(H2S)对人体肝脏可起到保护作用。本文通过分析肝脏缺血再灌注损伤的发生机制和硫化氢的生物作用机制,简要分析了硫化氢应用于肝脏缺血再灌注损伤中的作用。以期通过分析,能引起相关研究人员对硫化氢的注意,从而扩展硫化氢在临床上的应用途径,促进临床治疗研究发展。%Liver ischemia-reperfusion (hepatic ischemia reperfusion, HIRI) can cause serious damage to the liver function, especial y when suf ering from cir hosis of the liver, risk wil increase. Reasonable amounts of hydrogen sulfide (H2S) on the human body can protect liver. In this paper, through the analysis of the occurrence of liver ischemia-reperfusion injury mechanism and the biological mechanism of hydrogen sulfide, the brief analysis of the hydrogen sulfide is applied to the role of liver ischemia-reperfusion injury. Through the analysis, in order to can cause the at ention of the relevant researchers of hydrogen sulfide, and hydrogen sulfide in the clinical application of the way, promote the development of clinical research.

  18. 肝脏缺血再灌注损伤中硫化氢的作用新研究%To Study the Role of Hydrogen Sulfide in the Injury of Hepatic Ischemia Reperfusion

    Institute of Scientific and Technical Information of China (English)

    王佩; 王与胜

    2015-01-01

    Liver ischemia-reperfusion (hepatic ischemia reperfusion, HIRI) can cause serious damage to the liver function, especial y when suf ering from cir hosis of the liver, risk wil increase. Reasonable amounts of hydrogen sulfide (H2S) on the human body can protect liver. In this paper, through the analysis of the occurrence of liver ischemia-reperfusion injury mechanism and the biological mechanism of hydrogen sulfide, the brief analysis of the hydrogen sulfide is applied to the role of liver ischemia-reperfusion injury. Through the analysis, in order to can cause the at ention of the relevant researchers of hydrogen sulfide, and hydrogen sulfide in the clinical application of the way, promote the development of clinical research.%肝脏缺血再灌注(hepatic ischemia reperfusion,HIRI)会对肝功能造成严重损伤,尤其是当患有肝硬化时,风险便会加剧。合理剂量的硫化氢(H2S)对人体肝脏可起到保护作用。本文通过分析肝脏缺血再灌注损伤的发生机制和硫化氢的生物作用机制,简要分析了硫化氢应用于肝脏缺血再灌注损伤中的作用。以期通过分析,能引起相关研究人员对硫化氢的注意,从而扩展硫化氢在临床上的应用途径,促进临床治疗研究发展。

  19. Modeling of Sulfide Microenvironments on Mars

    Science.gov (United States)

    Schwenzer, S. P.; Bridges, J. C.; McAdam, A.; Steer, E. D.; Conrad, P. G.; Kelley, S. P.; Wiens, R. C.; Mangold, N.; Grotzinger, J.; Eigenbrode, J. L.; Franz, H. B.; Sutter, B.

    2016-01-01

    Yellowknife Bay (YKB; sol 124-198) is the second site that the Mars Science Laboratory Rover Curiosity investigated in detail on its mission in Gale Crater. YKB represents lake bed sediments from an overall neutral pH, low salinity environment, with a mineralogical composition which includes Ca-sulfates, Fe oxide/hydroxides, Fe-sulfides, amorphous material, and trioctahedral phyllosilicates. We investigate whether sulfide alteration could be associated with ancient habitable microenvironments in the Gale mudstones. Some textural evidence for such alteration may be pre-sent in the nodules present in the mudstone.

  20. Membrane for hydrogen recovery from streams containing hydrogen sulfide

    Science.gov (United States)

    Agarwal, Pradeep K.

    2007-01-16

    A membrane for hydrogen recovery from streams containing hydrogen sulfide is provided. The membrane comprises a substrate, a hydrogen permeable first membrane layer deposited on the substrate, and a second membrane layer deposited on the first layer. The second layer contains sulfides of transition metals and positioned on the on a feed side of the hydrogen sulfide stream. The present invention also includes a method for the direct decomposition of hydrogen sulfide to hydrogen and sulfur.

  1. New Measurements of the Densities of Copper, Nickel, and Iron Sulfide Liquids

    Science.gov (United States)

    Mioduszewski, L.; Kress, V. C.

    2005-12-01

    experience suggests that trivial modifications to the apparatus used in this study may provide an effective and reliable method for measuring liquid-solid surface energies in both sulfide and silicate systems. Such data would prove useful in both melt percolation and bubble nucleation and growth calculations.

  2. Formation of gold clusters on La-Ni mixed oxides and its catalytic performance for isomerization of allylic alcohols to saturated aldehydes

    International Nuclear Information System (INIS)

    Au/NiO catalyzed the isomerization of allylic alcohols to afford saturated aldehydes. La-Ni mixed oxide could stabilize Au(III) and afford gold clusters smaller than 1 nm by H2 reduction. The resulting Au clusters on La-Ni-O exhibited superior catalytic performance to Au/NiO for the isomerization of internal allylic alcohol, 2-octen-1-ol to octanal. (author)

  3. The reaction mechanism of the enantioselective Tsuji allylation: inner-sphere and outer-sphere pathways, internal rearrangements, and asymmetric C–C bond formation

    OpenAIRE

    Keith, John A.; Behenna, Douglas C.; Sherden, Nathaniel; Mohr, Justin T.; Ma, Sandy; Marinescu, Smaranda C.; Nielsen, Robert J.; Oxgaard, Jonas; Stoltz, Brian M.; Goddard, William A.

    2012-01-01

    We use first principles quantum mechanics (density functional theory) to report a detailed reaction mechanism of the asymmetric Tsuji allylation involving prochiral nucleophiles and nonprochiral allyl fragments, which is consistent with experimental findings. The observed enantioselectivity is best explained with an inner-sphere mechanism involving the formation of a 5-coordinate Pd species that undergoes a ligand rearrangement, which is selective with regard to the prochiral faces of the int...

  4. An Efficient Protocol for the Palladium-Catalyzed Asymmetric Decarboxylative Allylic Alkylation Using Low Palladium Concentrations and a Palladium(II) Precatalyst

    OpenAIRE

    Marziale, Alexander N.; Duquette, Douglas C.; Craig, Robert A.; Kim, Kelly E.; Liniger, Marc; Numajiri, Yoshitaka; Stoltz, Brian M.

    2015-01-01

    Enantioselective catalytic allylic alkylation for the synthesis of 2-alkyl-2-allylcycloalkanones and 3,3-disubstituted pyrrolidinones, piperidinones and piperazinones has been previously reported by our laboratory. The efficient construction of chiral all-carbon quaternary centers by allylic alkylation was previously achieved with a catalyst derived in situ from zero-valent palladium sources and chiral phosphinooxazoline (PHOX) ligands. We now report an improved reaction protocol with broad a...

  5. An Efficient Protocol for the Palladium-catalyzed Asymmetric Decarboxylative Allylic Alkylation Using Low Palladium Concentrations and a Palladium(II) Precatalyst

    OpenAIRE

    Marziale, Alexander N.; Duquette, Douglas C.; Craig, Robert A.; Kim, Kelly E.; Liniger, Marc; Numajiri, Yoshitaka; Stoltz, Brian M.

    2015-01-01

    Enantioselective catalytic allylic alkylation for the synthesis of 2-alkyl-2-allylcycloalkanones and 3,3-disubstituted pyrrolidinones, piperidinones and piperazinones has been previously reported by our laboratory. The efficient construction of chiral all-carbon quaternary centers by allylic alkylation was previously achieved with a catalyst derived in situ from zero valent palladium sources and chiral phosphinooxazoline (PHOX) ligands. We now report an improved reaction protocol with broad a...

  6. Study on electronic structures and properties of neutral and charged arsenic sulfides [As n S3 ((-1,0,+1)), n =1-6] with the Gaussian-3 scheme.

    Science.gov (United States)

    Liu, Bin; Yang, Jucai

    2015-12-01

    The structures and energies of neutral and charged arsenic sulfides As n S3 ((-1,0,+1)) (n = 1-6) were studied systematically with the G3 method. The ground-state structures of these species are reported. The ground-state structures of As n S3 with n ≥ 4 can be considered as resulting from the replacement of an As atom of the ground-state structure of neutral As n+1S2 by an S atom. In neutral As n S3, the character of sulfur bonding is edge-bridging. The ground-state structures of anion As n S3 (-) sometimes differ from their corresponding neutral structures. In such case, they exhibit a terminal sulfur atom. The ground-state structures of cationic As n S3 (+) are also sometimes different from the corresponding neutral ones. There, sulfur bonding can exhibit face-capping and arsenic can be four-fold coordinated. The potential energy surfaces of As4S3 (+) and As5S3 (+) are very flat and co-existence of various isomers of As4S3 (+) and As5S3 (+) is possible. Reliable adiabatic electron affinities (AEAs) and adiabatic ionization potentials (AIPs) of As n S3 are predicted. There are odd-even alternations in both AEAs and AIPs as a function of size. In addition, the reliable vertical detachment energies (VDEs) and vertical ionization potentials (VIPs) are presented. The dissociation energies (DEs) of S (and/or its ion S((-/+))) from As n S3 species and their ions were calculated to examine relative stabilities. The hardnesses and HOMO-LUMO gaps of As n S3 (n = 1-6) were evaluated and used to discuss relative chemical reactivity. PMID:26541467

  7. Influence of Gas Components on the Formation of Carbonyl Sulfide over Water-Gas Shift Catalyst B303Q

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Water-gas shift reaction catalyst at lower temperature (200-400 ℃) may improve the conversion of carbon monoxide. But carbonyl sulfide was found to be present over the sulfided cobaltmolybdenum/alumina catalyst for water-gas shift reaction. The influences of temperature, space velocity,and gas components on the formation of carbonyl sulfide over sulfided cobalt-molybdenum/alumina catalyst B303Q at 200-400 ℃ were studied in a tubular fixed-bed quartz-glass reactor under simulated water-gas shift conditions. The experimental results showed that the yield of carbonyl sulfide over B303Q catalyst reached a maximum at 220 ℃ with the increase in temperature, sharply decreased with the increase in space velocity and the content of water vapor, increased with the increase in the content of carbon monoxide and carbon dioxide, and its yield increased and then reached a stable value with the increase in the content of hydrogen and hydrogen sulfide. The formation mechanism of carbonyl sulfide over B303Q catalyst at 200-400 ℃ was discussed on the basis of how these factors influence the formation of COS. The yield of carbonyl sulfide over B303Q catalyst at 200-400 ℃ was the combined result of two reactions, that is, COS was first produced by the reaction of carbon monoxide with hydrogen sulfide,and then the as-produced COS was converted to hydrogen sulfide and carbon dioxide by hydrolysis. The mechanism of COS formation is assumed as follows: sulfur atoms in the Co9Ss-MoS2/Al2O3 crystal lattice were easily removed and formed carbonyl sulfide with CO, and then hydrogen sulfide in the water-gas shift gas reacted with the crystal lattice oxygen atoms in CoO-MoO3/Al2O3 to form Co9Ss-MoS2/Al2O3.This mechanism for the formation of COS over water-gas shift catalyst B303Q is in accordance with the Mars-Van Krevelen's redox mechanism over metal sulfide.

  8. T.O.C.S. : Hydrogen Sulfide Remission System

    OpenAIRE

    ECT Team, Purdue

    2007-01-01

    BioEnviroTech, Inc., (BET) developed Toxicity Odor Corrosion Sulfides (T.O.C.S.) Remission System for hydrogen sulfide reduction in municipal and industrial wastewater sewer, lift stations and force mains. This safe and cost effective biotreatment technology uses safe and natural bacteria to interrupt sulfide generation.

  9. 含硫天然气净化厂硫化氢泄漏分析及对策%Study of hydrogen sulfide leakage and dispersion in sour gas purification plants and countermeasures

    Institute of Scientific and Technical Information of China (English)

    高少华; 邹兵; 严龙; 张贺; 王振

    2012-01-01

    Processing facilities with higher risk of H2S leakage were determined through analyzing purifying process and various causes that may result in leakage from one of the sour gas plants in Northeastern Sichuan. The feed gas in the desulphurization units and acid gas in the sulfur recovery units , mainly consisting of H2S and CO2 ,were selected for the simulation through comparing the process pressures, flow rates and material compositions. Weather conditions and terrains around the plant were studied. According to the statistics of local meteorological data during the last 5 years, low wind speed and cloudy weather were typical weather conditions, and Dl. 5m/s was selected for calculation of hydrogen sulfide dispersion at the plant. Surface roughness length recommended for small refineries by American Petroleum Institute was adopted. The Immediately Dangerous to Life or Health (IDLH ) zones resulted from the hazardous gas dispersions were calculated with PHAST based on three different leakage holes with lmin, 5min and 30min. The IDLH downwind distances range from 41m to 1190m with the farthest one resulting from the large hole release of feed gas from the desulphurization units under the typical weather. The effects of wind speeds and atmospheric stabilities on the H2S dispersion were also simulated and discussed with small hole release. Some suggestions were made for setting online leak detection and interlock systems in order to reduce the risk of H2S leakage It has instructive meanings in avoiding or reducing casualties due to hydrogen sulfide poisoning.%以川东北某含硫天然气净化厂为对象,通过分析该净化厂的处理工艺及可能造成泄漏的各种原因,确定了硫化氢泄漏危险较高的生产单元.通过工艺压力、流量、物料组分的比对,选取了脱硫单元原料气和硫磺回收单元酸性气作为模拟泄漏物料.对该厂所在地的气象条件和厂区的地形地貌进行了调查,净化厂当地近5年风速

  10. Simulation study to determine the feasibility of injecting hydrogen sulfide, carbon dioxide and nitrogen gas injection to improve gas and oil recovery oil-rim reservoir

    Science.gov (United States)

    Eid, Mohamed El Gohary

    This study is combining two important and complicated processes; Enhanced Oil Recovery, EOR, from the oil rim and Enhanced Gas Recovery, EGR from the gas cap using nonhydrocarbon injection gases. EOR is proven technology that is continuously evolving to meet increased demand and oil production and desire to augment oil reserves. On the other hand, the rapid growth of the industrial and urban development has generated an unprecedented power demand, particularly during summer months. The required gas supplies to meet this demand are being stretched. To free up gas supply, alternative injectants to hydrocarbon gas are being reviewed to support reservoir pressure and maximize oil and gas recovery in oil rim reservoirs. In this study, a multi layered heterogeneous gas reservoir with an oil rim was selected to identify the most optimized development plan for maximum oil and gas recovery. The integrated reservoir characterization model and the pertinent transformed reservoir simulation history matched model were quality assured and quality checked. The development scheme is identified, in which the pattern and completion of the wells are optimized to best adapt to the heterogeneity of the reservoir. Lateral and maximum block contact holes will be investigated. The non-hydrocarbon gases considered for this study are hydrogen sulphide, carbon dioxide and nitrogen, utilized to investigate miscible and immiscible EOR processes. In November 2010, re-vaporization study, was completed successfully, the first in the UAE, with an ultimate objective is to examine the gas and condensate production in gas reservoir using non hydrocarbon gases. Field development options and proces schemes as well as reservoir management and long term business plans including phases of implementation will be identified and assured. The development option that maximizes the ultimate recovery factor will be evaluated and selected. The study achieved satisfactory results in integrating gas and oil

  11. Kinetic model for simultaneous leaching of zinc sulfide and manganese dioxide in the presence of iron-oxidizing bacteria

    OpenAIRE

    KAI, Takami; Suenaga, Yo-ich; Migita, Atsuko; TAKAHASHI, Takeshige

    2000-01-01

    The effect of iron-oxidizing bacteria on the simultaneous leaching of zinc sulfide and manganese dioxide was studied. Some researchers have reported the enhancement of the leaching rate during the simultaneous leaching of metal oxides and metal sulfides. In the present study, we examined the effect of the presence of Thiobacillus ferrooxidans in the simultaneous leaching. We also examined the reaction rates during the simultaneous leaching in the presence of the bacteria in order to study the...

  12. Density Functional Investigation of Methanethiol and Dimethyl Sulfide Adsorption on Zeolite

    Institute of Scientific and Technical Information of China (English)

    Renqing Lü; Guangmin Qiu; Chenguang Liu

    2006-01-01

    The density functional theory and cluster model methods have been employed to investigate the interactions between methanethiol, dimethyl sulfide and zeolites. The molecular complexes formed by adsorption of methanethiol or dimethyl sulfide on silanol H3SiOSi(OH)2OSiH3 with five coordination forms or four coordination forms, and complexes formed by interactions of Br(o)nsted acid sites of bridging hydroxyl H3Si(OH)Al(OH)2OSiH3 with methanethiol or dimethyl sulfide have been investigated. Full optimization and frequency analysis of all cluster models have been carried out using the B3LYP hybrid method at 6-31+G (d,p) basis set level for hydrogen, silicon, aluminum, oxygen,carbon, and sulfur atoms. The structures and energy changes of different coordination forms between methanethiol and H3Si(OH)Al(OH)2OSiH3, dimethyl sulfide and H3Si(OH)Al(OH)2OSiH3, methanethiol and H3SiOSi(OH)2OSiH3, dimethyl sulfide and H3SiOSi(OH)2OSiH3 complexes have been comparatively studied. The calculated results showed the nature of interactions that led to the formation of all complexes was van der Waals force confirmed by an insignificant change of geometric structures and properties. The conclusions that methanethiol and dimethyl sulfide molecules were adsorbed on bridging hydroxyl group prior to silanol group were obtained on the basis of adsorption heat, the most stable adsorption models of a 6 ring structure for interaction between bridging hydroxyl and methanethiol, and a 7 ring structure for interaction between bridging hydroxyl and dimethyl sulfide.

  13. Transformation of iron sulfide to greigite by nitrite produced by oil field bacteria.

    Science.gov (United States)

    Lin, Shiping; Krause, Federico; Voordouw, Gerrit

    2009-05-01

    Nitrate, injected into oil fields, can oxidize sulfide formed by sulfate-reducing bacteria (SRB) through the action of nitrate-reducing sulfide-oxidizing bacteria (NR-SOB). When reservoir rock contains siderite (FeCO(3)), the sulfide formed is immobilized as iron sulfide minerals, e.g. mackinawite (FeS). The aim of our study was to determine the extent to which oil field NR-SOB can oxidize or transform FeS. Because no NR-SOB capable of growth with FeS were isolated, the well-characterized oil field isolate Sulfurimonas sp. strain CVO was used. When strain CVO was presented with a mixture of chemically formed FeS and dissolved sulfide (HS(-)), it only oxidized the HS(-). The FeS remained acid soluble and non-magnetic indicating that it was not transformed. In contrast, when the FeS was formed by adding FeCl(2) to a culture of SRB which gradually produced sulfide, precipitating FeS, and to which strain CVO and nitrate were subsequently added, transformation of the FeS to a magnetic, less acid-soluble form was observed. X-ray diffraction and energy-dispersive spectrometry indicated the transformed mineral to be greigite (Fe(3)S(4)). Addition of nitrite to cultures of SRB, containing microbially formed FeS, was similarly effective. Nitrite reacts chemically with HS(-) to form polysulfide and sulfur (S(0)), which then transforms SRB-formed FeS to greigite, possibly via a sulfur addition pathway (3FeS + S(0) --> Fe(3)S(4)). Further chemical transformation to pyrite (FeS(2)) is expected at higher temperatures (>60 degrees C). Hence, nitrate injection into oil fields may lead to NR-SOB-mediated and chemical mineral transformations, increasing the sulfide-binding capacity of reservoir rock. Because of mineral volume decreases, these transformations may also increase reservoir injectivity. PMID:19290520

  14. Long-term field test of an electrochemical method for sulfide removal from sewage.

    Science.gov (United States)

    Pikaar, Ilje; Li, Eugena; Rozendal, René A; Yuan, Zhiguo; Keller, Jürg; Rabaey, Korneel

    2012-06-01

    Corrosion caused by hydrogen sulfide leads to significant costs for the rehabilitation or replacement of corroded sewer pipes. Conventional methods to prevent sewer corrosion normally involve the dosing of significant amounts of chemicals with the associated transport and storage costs as well as considerable maintenance and control requirement. Recently, a novel chemical free method for sulfide abatement based on electrochemical sulfide oxidation was shown to be highly effective for the removal of sulfide from synthetic and real sewage. Here, we report on the electrochemical removal of sulfide using Ta/Ir and Pt/Ir coated titanium electrodes under simulated sewer conditions during field trials. The results showed that sulfide can successfully be removed to levels below the normal target value at the end of a simulated rising main (i.e. Scaling of the electrode and the membrane was observed in the cathode compartment and as a result the cell potentials increased over time. The cathode potentials returned to their original potential after switching the polarity every two days, but a more frequent switching would be needed to reduce the energy requirements of the system. Accelerated lifetime experiments indicated that a lifetime of 6.0 ± 1.9 years can be expected under polarity switching conditions at a pH of 14 and significantly longer at lower pH values. As operating the system without switching simplifies construction as well as operation, the choice whether to switch or not will in practice depend on operational cost (higher/lower energy) versus capital cost (reactor and peripherals). Irrespective of the approach, our study demonstrates that electrochemical sulfide control in sewer systems may be an attractive new option. PMID:22483834

  15. Adsorption of dimethyl sulfide from aqueous solution by a cost-effective bamboo charcoal.

    Science.gov (United States)

    Wang, Ming; Huang, Zheng-Hong; Liu, Guangjia; Kang, Feiyu

    2011-06-15

    The adsorption of dimethyl sulfide from an aqueous solution by a cost-effective bamboo charcoal from Dendrocalamus was studied in comparison with other carbon adsorbents. The bamboo charcoal exhibited superior adsorption on dimethyl sulfide compared with powdered activated carbons at different adsorbent dosages. The adsorption characteristics of dimethyl sulfide onto bamboo charcoal were investigated under varying experimental conditions such as particle size, contact time, initial concentration and adsorbent dosage. The dimethyl sulfide removal was enhanced from 31 to 63% as the particle size was decreased from 24-40 to >300 mesh for the bamboo charcoal. The removal efficiency increased with increasing the adsorbent dosage from 0.5 to 10mg, and reached 70% removal efficiency at 10mg adsorbed. The adsorption capacity (μg/g) increased with increasing concentration of dimethyl sulfide while the removal efficiency decreased. The adsorption process conforms well to a pseudo-second-order kinetics model. The adsorption of dimethyl sulfide is more appropriately described by the Freundlich isotherm (R(2), 0.9926) than by the Langmuir isotherm (R(2), 0.8685). Bamboo charcoal was characterized by various analytical methods to understand the adsorption mechanism. Bamboo charcoal is abundant in acidic and alcohol functional groups normally not observed in PAC. A distinct difference is that the superior mineral composition of Fe (0.4 wt%) and Mn (0.6 wt%) was detected in bamboo charcoal-elements not found in PAC. Acidic functional group and specific adsorption sites would be responsible for the strong adsorption of dimethyl sulfide onto bamboo charcoal of Dendrocalamus origin. PMID:21549503

  16. Crystal structure of (Z-3-allyl-5-(3-bromobenzylidene-2-sulfanylidene-1,3-thiazolidin-4-one

    Directory of Open Access Journals (Sweden)

    Rahhal El Ajlaoui

    2015-12-01

    Full Text Available In the title compound, C13H10BrNOS2, the rhodanine (systematic name: 2-sulfanylidene-1,3-thiazolidin-4-one and the 3-bromobenzylidene ring systems are inclined slightly, forming a dihedral angle of 5.86 (12°. The rhodanine moiety is linked to an allyl group at the N atom and to the 3-bromobenzylidene ring system. The allyl group, C=C—C, is nearly perpendicular to the mean plane through the rhodanine ring, maling a dihedral angle of 87.2 (5°. In the crystal, molecules are linked by pairs of C—H...O hydrogen bonds, forming inversion dimers with an R22(10 ring motif.

  17. Coupling between anammox and autotrophic denitrification for simultaneous removal of ammonium and sulfide by enriched marine sediments.

    Science.gov (United States)

    Rios-Del Toro, E Emilia; Cervantes, Francisco J

    2016-06-01

    In the present study, the capacity of enrichments derived from marine sediments collected from different sites of the Mexican littoral to perform anaerobic ammonium oxidation (anammox) coupled to sulfide-dependent denitrification for simultaneous removal of ammonium and sulfide linked to nitrite reduction was evaluated. Sulfide-dependent denitrification out-competed anammox during the simultaneous oxidation of sulfide and ammonium. Significant accumulation of elemental sulfur (ca. 14-30 % of added sulfide) occurred during the coupling between the two respiratory processes, while ammonium was partly oxidized (31-47 %) due to nitrite limitation imposed in sediment incubations. Nevertheless, mass balances revealed up to 38 % more oxidation of the electron donors available (ammonium and sulfide) than that expected from stoichiometry. Recycling of nitrite, from nitrate produced through anammox, is proposed to contribute to extra oxidation of sulfide, while additional ammonium oxidation is suggested by sulfate-reducing anammox (SR-anammox). The complex interaction between nitrogenous and sulfurous compounds occurring through the concomitant presence of autotrophic denitrification, conventional anammox and SR-anammox may significantly drive the nitrogen and sulfur fluxes in marine environments. PMID:26994921

  18. Phosphorus mobilization by sulfide oxidation in carbonate sediments from seagrass and unvegetated sites in the US Virgin Islands

    DEFF Research Database (Denmark)

    Jensen, Henning; Pedersen, Ole; Koch, M. R.;

    sources of nutrients compared to pristine sites. These results, along with those from our earlier studies in Florida Bay, a carbonate seagrass-dominated estuary, highlight the potential importance of P release from acid dissolution of carbonate-bound P pools. Session #:046 Date: 01-29-09 Time: 16:45......PHOSPHORUS MOBILIZATION BY SULFIDE OXIDATION IN CARBONATE SEDIMENTS FROM SEAGRASS AND UNVEGETATED SITES IN THE US VIRGIN ISLANDS Sulfide produced by sulfate reduction (SR) can be oxidized by seagrass root O2 flux in shallow carbonate sediments low in Fe. The sulfuric acid produced from sulfide...

  19. Measurement and biological significance of the volatile sulfur compounds hydrogen sulfide, methanethiol and dimethyl sulfide in various biological matrices

    NARCIS (Netherlands)

    Tangerman, Albert

    2009-01-01

    This review deals with the measurement of the volatile Sulfur compounds hydrogen sulfide, methanethiol and dimethyl sulfide in various biological matrices of rats and humans (blood, serum, tissues, urine, breath, feces and flatus). Hydrogen sulfide and methanethiol both contain the active thiol (-SH

  20. The diagenesis of carbohydrates by hydrogen sulfide

    Science.gov (United States)

    Mango, Frank D.

    1983-08-01

    Carbohydrates react with hydrogen sulfide under low temperature (100° to 200°C) yielding a variety of organosulfur compounds including thiophenes, thiols, sulfides and sulfones. A polymer is also produced, whose elemental composition is within the range of natural coals. When reductive dehydration is carried out in the presence of hydrocarbon, organosulfur compounds are formed in the carbon number range of the hydrocarbon used. In these processes, an active hydrogen transfer catalyst is produced which facilitates the passage of hydrogen between normal paraffins and saccharide units, distributing sulfur between these two families primarily in the form of thiophene rings. The simplicity of these systems - H 2S, carbohydrates, H 2O, hydrocarbon - and the facility of the chemistry would suggest that the carbohydrates and hydrogen sulfide may be important agents in the diagenetic processes leading to petroleum and coal. Carbohydrate reduction by hydrogen sulfide may constitute an important route through which certain organosulfur compounds found in petroleum and coal entered these materials in early diagenesis.

  1. Support Effect in Hydrodesulfurization over Ruthenium Sulfide

    Czech Academy of Sciences Publication Activity Database

    Gulková, Daniela; Kaluža, Luděk; Vít, Zdeněk; Zdražil, Miroslav

    Prague : JHI, 2008, s. 58-s. 59. [Symposium on Catalysis /40./. Prague (CZ), 03.11.2008-05.11.2008] R&D Projects: GA ČR GA104/06/0705 Institutional research plan: CEZ:AV0Z40720504 Keywords : ruthenium sulfide * hydrodesulfurization * support Subject RIV: CF - Physical ; Theoretical Chemistry

  2. Support Effect in Hydrodesulfurization over Ruthenium Sulfide

    Czech Academy of Sciences Publication Activity Database

    Gulková, Daniela; Kaluža, Luděk; Vít, Zdeněk; Zdražil, Miroslav

    2009-01-01

    Roč. 51, č. 2 (2009), s. 146-149. ISSN 1337-7027 R&D Projects: GA ČR GA104/06/0705 Institutional research plan: CEZ:AV0Z40720504 Keywords : ruthenium sulfide * hydrodesulfurization * support effect Subject RIV: CC - Organic Chemistry

  3. Reaction between Hydrogen Sulfide and Limestone Calcines

    Czech Academy of Sciences Publication Activity Database

    Hartman, Miloslav; Svoboda, Karel; Trnka, Otakar; Čermák, Jiří

    2002-01-01

    Roč. 41, č. 10 (2002), s. 2392-2398. ISSN 0888-5885 R&D Projects: GA AV ČR IAA4072711; GA AV ČR IAA4072801 Keywords : hydrogen sulfide * limestone calcines * desulfurization Subject RIV: CI - Industrial Chemistry, Chemical Engineering Impact factor: 1.247, year: 2002

  4. Antioxidant and Hypolipidemic Potential of Aged Garlic Extract and Its Constituent, S-Allyl Cysteine, in Rats

    OpenAIRE

    Syed Mohammed Basheeruddin Asdaq

    2015-01-01

    Aged garlic extract (AGE) is one of the unique preparations standardized with 100% bioavailable active ingredients found in the bloodstream. The current research was aimed at exploring the role of AGE and its chief active constituent, s-allyl cysteine (SAC) as antioxidant and hypolipidemic agent in rats. At the end of treatment of AGE and SAC, separated serum and freshly prepared liver tissue homogenate were analyzed for biochemical enzymes and biomarkers to evaluate and compare potencies of ...

  5. Hydroxymethylation beyond Carbonylation: Enantioselective Iridium-Catalyzed Reductive Coupling of Formaldehyde with Allylic Acetates via Enantiotopic π-Facial Discrimination.

    Science.gov (United States)

    Garza, Victoria J; Krische, Michael J

    2016-03-23

    Chiral iridium complexes modified by SEGPHOS catalyze the 2-propanol-mediated reductive coupling of branched allylic acetates 1a-1o with formaldehyde to form primary homoallylic alcohols 2a-2o with excellent control of regio- and enantioselectivity. These processes, which rely on enantiotopic π-facial discrimination of σ-allyliridium intermediates, represent the first examples of enantioselective formaldehyde C-C coupling beyond aldol addition. PMID:26958737

  6. Statistic evaluation of cysteine and allyl alcohol as additives for Cu-Zn coatings from citrate baths

    OpenAIRE

    Julyana Ribeiro Garcia; Dalva Cristina Baptista do Lago; Fernando Lucas Gonçalves Silva; Eliane D'Elia; Aderval Severino Luna; Lilian Ferreira de Senna

    2013-01-01

    In the present work, cysteine and allyl alcohol were added to citrate baths as additives to Cu-Zn coatings on steel substrates. In order to verify the effects of the deposition parameters (current density, mechanical stirring speed, and additives) on the coating composition, electrochemical behavior, morphology, and microstructure properties of Cu-Zn coatings, the electrodeposition of the alloy was carried out using an experimental composite design 2³, in which these parameters were considere...

  7. Rhodium(III)-catalyzed C-C coupling of 7-azaindoles with vinyl acetates and allyl acetates.

    Science.gov (United States)

    Li, Shuai-Shuai; Wang, Cheng-Qi; Lin, Hui; Zhang, Xiao-Mei; Dong, Lin

    2016-01-01

    The behaviour of electron-rich alkenes with 7-azaindoles in rhodium(III)-catalyzed C-H activation is investigated. Various substituted vinyl acetates and allyl acetates as coupling partners reacted smoothly providing a wide variety of 7-azaindole derivatives, and the selectivity of the coupling reaction is alkene-dependent. In addition, the approaches of rhodium(III)-catalyzed dehydrogenative Heck-type reaction (DHR) and carbonylation reaction were quite novel and simple. PMID:26553424

  8. Hydrogen sulfide and nervous system regulation

    Institute of Scientific and Technical Information of China (English)

    ZHOU Cheng-fang; TANG Xiao-qing

    2011-01-01

    Objective This review discusses the current status and progress in studies on the roles of hydrogen sulfide (H2S) in regulation of neurotoxicity,neuroprotection,and neuromodulator,as well as its therapeutic potential for neurodegenerative disorders.Data sources The data used in this review were mainly from Medline and PubMed published in English from 2001 to August 2011.The search terms were “hydrogen sulfide”,“neuron”,and “neurodegenerative disorders”.Study selection Articles regarding the regulation of neuronal function,the protection against neuronal damage and neurological diseases,and their possible cellular and molecular mechanisms associated with H2S were selected.Results The inhibited generation of endogenous H2S is implicated in 1-methy-4-phenylpyridinium ion,6-OHDA,and homocysteine-triggered neurotoxicity.H2S elicits neuroprotection in Alzheimer's disease and Parkinson's disease models as well as protecting neurons against oxidative stress,ischemia,and hypoxia-induced neuronal death.H2S offers anti-oxidant,anti-inflammatory and anti-apoptotic effects,as well as activates ATP-sensitive potassium channels and cystic fibrosis transmembrane conductance regulator Cl- channels.H2S regulates the long-term potentiation (LTP) and GABAB receptors in the hippocampus,as well as intracellular calcium and pH homeostasis in neurons and glia cells.Conclusions These articles suggest that endogenous H2S may regulate the toxicity of neurotoxin.H2S not only acts as a neuroprotectant but also serves as a novel neuromodulator.

  9. Selective Sulfidation of Lead Smelter Slag with Pyrite and Flotation Behavior of Synthetic ZnS

    Science.gov (United States)

    Han, Junwei; Liu, Wei; Wang, Dawei; Jiao, Fen; Zhang, Tianfu; Qin, Wenqing

    2016-05-01

    The selective sulfidation of lead smelter slag with pyrite in the presence of carbon and Na salts, and the flotation behavior of synthetic ZnS were studied. The effects of temperature, time, pyrite dosage, Na salts, and carbon additions were investigated based on thermodynamic calculation, and correspondingly, the growth mechanism of ZnS particles was studied at high temperatures. The results indicated that the zinc in lead smelter slag was selectively converted into zinc sulfides by sulfidation roasting. The sulfidation degree of zinc was increased until the temperature, time, pyrite, and carbon dosages reached their optimum values, under which it was more than 95 pct. The growth of ZnS particles largely depended upon roasting temperature, and the ZnS grains were significantly increased above 1373 K (1100 °C) due to the formation of a liquid phase. After the roasting, the zinc sulfides generated had a good floatability, and 88.34 pct of zinc was recovered by conventional flotation.

  10. A combined neutron and x-ray diffraction study of short- and intermediate-range structural characteristics of Ge-As sulfide glasses

    International Nuclear Information System (INIS)

    A combination of neutron and x-ray diffraction has been employed to study the compositional dependence of the atomic structures of GexAsxS100-2x glasses with S concentration varying between 33.3 and 70.0 at.%. The nearest-neighbor coordination numbers of Ge and As atoms are always found to be 4 and 3, respectively, irrespective of the glass composition. Ge and As atoms have primarily heteropolar bonding to S atoms in stoichiometric and S-excess glasses with x≤18.2. Low and intermediate levels of deficiency of S (20≤x≤25) are accommodated via the formation of homopolar As-As bonds while Ge atoms remain primarily bonded to four S atoms, resulting in As-rich regions in the glass structure. Ge starts to participate in metal-metal bonding only in the highly S-deficient glasses with 27.5≤x≤33.3. The intermediate-range order and its topological influence on atomic packing in these three compositional regions, in the order of increasing deficiency in S, are controlled by (a) a mixed GeS2 and As2S3 network, (b) the coexistence of a GeS2 network and As clusters, and (c) large Ge-As metal-rich regions. This evolution of the intermediate-range structure with composition is consistent with the corresponding variation of the position, intensity and width of the first sharp diffraction peak in the structure factor

  11. Regioselective synthesis of novel 3-allyl-2-(substituted imino)-4-phenyl-3H-thiazole and 2,2‧-(1,3-phenylene)bis(3-substituted-2-imino-4-phenyl-3H-thiazole) derivatives as antibacterial agents

    Science.gov (United States)

    Abbasi Shiran, Jafar; Yahyazadeh, Asieh; Mamaghani, Manouchehr; Rassa, Mehdi

    2013-05-01

    Several novel 3-allyl-2-(substituted imino)-4-phenyl-3H-thiazole derivatives were synthesized by the reaction of allyl-thioureas and 2-bromoacetophenone. We also report the synthesis of bis-allyl-3H thiazoles using the reaction of various isothiocyanates and 1,3-phenylenediamine. The structures of all compounds were characterized by spectral and elemental analysis. Most of the synthesized compounds exhibited efficient antibacterial activities against Salmonella enterica, Micrococcus luteus, Bacillus subtilis and Pseudomonas aeruginosa.

  12. Nuclear Spin Lattice Relaxation and Conductivity Studies of the Non-Arrhenius Conductivity Behavior in Lithium Fast Ion Conducting Sulfide Glasses

    Energy Technology Data Exchange (ETDEWEB)

    Benjamin Michael Meyer

    2003-05-31

    As time progresses, the world is using up more of the planet's natural resources. Without technological advances, the day will eventually arrive when these natural resources will no longer be sufficient to supply all of the energy needs. As a result, society is seeing a push for the development of alternative fuel sources such as wind power, solar power, fuel cells, and etc. These pursuits are even occurring in the state of Iowa with increasing social pressure to incorporate larger percentages of ethanol in gasoline. Consumers are increasingly demanding that energy sources be more powerful, more durable, and, ultimately, more cost efficient. Fast Ionic Conducting (FIC) glasses are a material that offers great potential for the development of new batteries and/or fuel cells to help inspire the energy density of battery power supplies. This dissertation probes the mechanisms by which ions conduct in these glasses. A variety of different experimental techniques give a better understanding of the interesting materials science taking place within these systems. This dissertation discusses Nuclear Magnetic Resonance (NMR) techniques performed on FIC glasses over the past few years. These NMR results have been complimented with other measurement techniques, primarily impedance spectroscopy, to develop models that describe the mechanisms by which ionic conduction takes place and the dependence of the ion dynamics on the local structure of the glass. The aim of these measurements was to probe the cause of a non-Arrhenius behavior of the conductivity which has been seen at high temperatures in the silver thio-borosilicate glasses. One aspect that will be addressed is if this behavior is unique to silver containing fast ion conducting glasses. more specifically, this study will determine if a non-Arrhenius correlation time, {tau}, can be observed in the Nuclear Spin Lattice Relaxation (NSLR) measurements. If so, then can this behavior be modeled with a new single

  13. Silver-based electrochemical sensors for sulfide monitoring in deep-sea environments: New approaches based on autonomous measurement

    Science.gov (United States)

    Contreira Pereira, Leonardo; Peru, Erwan; Le Bris, Nadine

    2014-05-01

    A large variety of sulfidic environments have been described in the deep-sea since the late seventies, such as hydrothermal vents, cold seeps, organic falls or sub-seafloor microbial habitats. The reactivity of sulfide toward living organisms is a key concern in the exploration and study of these ecosystems, especially at hydrothermal vents where sulfide is a predominant energy source for chemosynthesis. However, the dynamics of sulfide gradients in these marine environments are still poorly documented, constraining the knowledge of their biogeochemical and ecological consequences. In this context, the development of sulfide autonomous sensors became a primary challenge. Measurement tools capable to capture the temporal variability of sulfide concentrations and related parameters are particularly needed, owing to the variability of environments at hydrothermal vents. Silver sulfide potentiometry, which was already applied in situ for punctual measurements, and a new voltammetric method based on bare silver, an electrode material which avoids the need for complex and repeated conditioning of the electrodes, are particularly suitable for unattended use. The advantages and limits of the potentiometric and voltammetric sensing techniques using solid-state electrodes were compared, with respect to the major requirements: concentration ranges; sensitivity to change of pH and temperature; minimum measurement rate; spatial resolution; autonomy; stability and reliability over time. Laboratory tests, combined with unprecedented series of in situ deployments in deep sea and other shallow water sulfidic environments, depict the potential of these tools for monitoring sulfide fluctuations in deep-sea habitats over weeks to months, and their use for investigation of the biogeochemical transformation of sulfur over time. Such sensors, improves the knowledge from these hardly accessible environments and could also reveal usefull to study shallow coastal waters, where sulfidic

  14. Microbial oxidation of mixtures of methylmercaptan and hydrogen sulfide.

    Science.gov (United States)

    Subramaniyan, A; Kolhatkar, R; Sublette, K L; Beitle, R

    1998-01-01

    Refinery spent-sulfidic caustic, containing only inorganic sulfides, has previously been shown to be amenable to biotreatment with Thiobacillus denitrificans strain F with complete oxidation of sulfides to sulfate. However, many spent caustics contain mercaptans that cannot be metabolized by this strict autotroph. An aerobic enrichment culture was developed from mixed Thiobacilli and activated sludge that was capable of simultaneous oxidation of inorganic sulfide and mercaptans using hydrogen sulfide (H2S) and methylmercaptan (MeSH) gas feeds used to simulate the inorganic and organic sulfur of a spent-sulfidic caustic. The enrichment culture was also capable of biotreatment of an actual mercaptan-containing, spent-sulfidic caustic but at lower rates than predicted by operation on MeSH and H2S fed to the culture in the gas phase, indicating that the caustic contained other inhibitory components. PMID:18576062

  15. 降低长坡选矿厂全浮硫化矿中锡损失的试验研究%Experimental study on reducing the loss of cassiterite in bulk flotation sulfides in Changpo plant

    Institute of Scientific and Technical Information of China (English)

    周德炎

    2012-01-01

    针对长坡选矿厂在全浮流程中添加大量药剂回收硫化矿,细粒、微细粒锡石易损失于全浮硫化矿中的特点,采用组合抑制剂BY-6抑制锡石,降低锡损失,使损失于全浮硫化矿中的锡石含量仅为13.48%。%In Changpo plant, amounts of agents were used to recover sulfides, which led to some fine or ultra-fme cassiterites loss in bulk flotation sulfides. In order to solve this problem, a combined depressant named BY-6 was adopted. The results showed the loss of fine or ultra-fine cassiterites could be effectively controlled and the mass ratio of cassiterite in bulk flotation sulfides was only 14.48%.

  16. Hydrogen sulfide at high pressure: change in stoichiometry

    OpenAIRE

    Goncharov, Alexander F.; Lobanov, Sergey; Kruglov, Ivan; Zhao, Xiao-Miao; Chen, Xiao-Jia; Oganov, Artem R.; Konôpková, Zuzana; Prakapenka, Vitali

    2016-01-01

    Hydrogen-sulfide (H2S) was studied by x-ray synchrotron diffraction (XRD) and Raman spectroscopy up to 150 GPa at 180-295 K and by quantum-mechanical variable-composition evolutionary simulations. The experiments show that H2S becomes unstable with respect to formation of new compounds with different structure and composition, including Cccm and a body-centered-cubic (bcc) like (R3m or Im-3m) H3S, the latter one predicted previously to show a record-high superconducting transition temperature...

  17. Dynamic corrosion of copper-nickel sulfide by Acidithiobacillus ferrooxidans

    Institute of Scientific and Technical Information of China (English)

    TONG Lin-lin; JIANG Mao-fa; YANG Hong-ying; YU Juan; FAN You-jing; ZHANG Yao

    2009-01-01

    The dynamic corrosion process of bio-oxidation of copper-nickel sulfide from Karatungk in northern Xinjiang Province of China was studied. The polished wafer of the copper-nickel sulphide was used to carry on a series of oxidation corrosion experiment by Acidithiobacillus ferrooxidans. The changes of superficial corrosion appearance and the mineral dynamic corrosion process were discovered by microscope observation. Then, the galvanic cell model was established, and the bio-oxidation activation order of typical copper-nickel sulphide minerals was ascertained as pyrrhotite>pentlandite>chalocopyrite.

  18. Luminescence of high-doped calcium sulfide crystals

    International Nuclear Information System (INIS)

    Calcium sulfide crystals grown by high-temperatur mineralization tecnique have been studied. Bands peaked at 2.12 and 2.5-2.7 eV are considered the most invariable features of cathodoluminescence and photoluminescence spectra. It has been found that the 2.12 eV band is conditioned by optical electronic transitions in Mn2+ ions substituted for Ca2+ ions in the host lattice. The exciton mechanism of energy transfer to centers, that are responsible for the high-energy luminescence band, is discussed

  19. HYDROGEN SULFIDE ADSORPTION BY ALKALINE IMPREGNATED COCONUT SHELL ACTIVATED CARBON

    OpenAIRE

    HUI SUN CHOO; LEE CHUNG LAU; ABDUL RAHMAN MOHAMED; KEAT TEONG LEE

    2013-01-01

    Biogas is one type of renewable energy which can be burnt to produce heat and electricity. However, it cannot be burnt directly due to the presence of hydrogen sulfide (H2S) which is highly corrosive to gas engine. In this study, coconut shell activated carbon (CSAC) was applied as a porous adsorbent for H2S removal. The effect of amount of activated carbon and flow rate of gas stream toward adsorption capacity were investigated. Then, the activated carbons were impregnated by three types of ...

  20. The Role of Water for Photodecomposition of Aqueous Hydrogen Sulfide Using Stratified Photocatalyst--Experimental Part

    International Nuclear Information System (INIS)

    Splitting of hydrogen sulfide using sunlight is a useful reaction to produce hydrogen. Alkaline sulfide solution, which is prepared by dissolving hydrogen sulfide into alkaline water, is selected as the reaction medium of photocatalytic hydrogen generation reaction. In this system, the photocatalytic reaction is assumed to occur as follows: 2H2O + 2e- → H2 + 2OH- (1) 2S2- + 2h+ → S22- (2) However, as the reaction progresses white solids precipitate in the reaction medium. Furthermore, the HPLC analysis suggested that the ratio between the consumption of sulfide ion and the amount of hydrogen generation was about 3:2, which is not stoichiometric. Thus, in this paper, we characterized the white solid precipitate and tried to optimize the solution condition to prevent the precipitation of the same. From our study, the white solid precipitate was confirmed as sulfur derived from the oxidation of the disulfide ion. It was confirmed that the addition of sulfite ions prevented the oxidation of disulfide ions, which causes the precipitation. In the absence of sulfite ions and for sufide ion concentration less than 0.1M, the precipitation of sulfur occurs in a very short reaction time. On the other hand the hydrogen evolution rate retarded when the sulfide ion concentration is higher than 0.1M. This was due to the degradation of the stratified CdS particles. Thus, the optimal concentration of Na2S solution was determined to be around 0.1M

  1. Formation of Fe-sulfides in cultures of sulfate-reducing bacteria

    International Nuclear Information System (INIS)

    The purpose of this study was to synthesize Fe-sulfides produced with sulfate-reducing bacteria under experimental laboratory conditions. Fe-sulfides were precipitated with biologically produced sulfide in cultures growing at 22, 45, and 60 deg. C for up to 16 weeks. Abiotic controls were prepared by reacting liquid media with Na2S solutions. Precipitates were collected anaerobically, freeze-dried and analyzed by X-ray diffraction. Additional analyses included total Fe and S content, magnetic susceptibility, specific surface area, and scanning electron microscopy. Mackinawite (FeS) and greigite (Fe3S4) were the dominant iron sulfide phases formed in sulfate-reducing bacterial cultures. An increase in the incubation temperature from 22 to 60 deg. C enhanced the crystallinity of the Fe-sulfides. Generally, greigite was more prevalent in abiotic samples and mackinawite in biogenic materials. Pyrite (FeS2) was also found in abiotic precipitates. Abiotic samples had a higher magnetic susceptibility because of the greigite and displayed improved crystallinity compared to biotic materials.

  2. Formation of Fe-sulfides in cultures of sulfate-reducing bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Gramp, Jonathan P. [Department of Microbiology, Ohio State University, 484 W. 12th Avenue, Columbus, OH 43210 (United States); Bigham, Jerry M.; Jones, F. Sandy [School of Environment and Natural Resources, 2021 Coffey Road, Ohio State University, Columbus, OH 43210 (United States); Tuovinen, Olli H., E-mail: tuovinen.1@osu.edu [Department of Microbiology, Ohio State University, 484 W. 12th Avenue, Columbus, OH 43210 (United States) and Department of Chemistry and Bioengineering, Tampere University of Technology, P.O. Box 541, FI 33101 Tampere (Finland)

    2010-03-15

    The purpose of this study was to synthesize Fe-sulfides produced with sulfate-reducing bacteria under experimental laboratory conditions. Fe-sulfides were precipitated with biologically produced sulfide in cultures growing at 22, 45, and 60 deg. C for up to 16 weeks. Abiotic controls were prepared by reacting liquid media with Na{sub 2}S solutions. Precipitates were collected anaerobically, freeze-dried and analyzed by X-ray diffraction. Additional analyses included total Fe and S content, magnetic susceptibility, specific surface area, and scanning electron microscopy. Mackinawite (FeS) and greigite (Fe{sub 3}S{sub 4}) were the dominant iron sulfide phases formed in sulfate-reducing bacterial cultures. An increase in the incubation temperature from 22 to 60 deg. C enhanced the crystallinity of the Fe-sulfides. Generally, greigite was more prevalent in abiotic samples and mackinawite in biogenic materials. Pyrite (FeS{sub 2}) was also found in abiotic precipitates. Abiotic samples had a higher magnetic susceptibility because of the greigite and displayed improved crystallinity compared to biotic materials.

  3. Formation of Fe-sulfides in cultures of sulfate-reducing bacteria.

    Science.gov (United States)

    Gramp, Jonathan P; Bigham, Jerry M; Jones, F Sandy; Tuovinen, Olli H

    2010-03-15

    The purpose of this study was to synthesize Fe-sulfides produced with sulfate-reducing bacteria under experimental laboratory conditions. Fe-sulfides were precipitated with biologically produced sulfide in cultures growing at 22, 45, and 60 degrees C for up to 16 weeks. Abiotic controls were prepared by reacting liquid media with Na(2)S solutions. Precipitates were collected anaerobically, freeze-dried and analyzed by X-ray diffraction. Additional analyses included total Fe and S content, magnetic susceptibility, specific surface area, and scanning electron microscopy. Mackinawite (FeS) and greigite (Fe(3)S(4)) were the dominant iron sulfide phases formed in sulfate-reducing bacterial cultures. An increase in the incubation temperature from 22 to 60 degrees C enhanced the crystallinity of the Fe-sulfides. Generally, greigite was more prevalent in abiotic samples and mackinawite in biogenic materials. Pyrite (FeS(2)) was also found in abiotic precipitates. Abiotic samples had a higher magnetic susceptibility because of the greigite and displayed improved crystallinity compared to biotic materials. PMID:19962824

  4. Modeling the Effect of Dissolved Hydrogen Sulfide on Mg2+-water Complex on Dolomite {104} Surfaces

    CERN Document Server

    Shen, Zhizhang; Brown, Philip E; Szlufarska, Izabela; Xu, Huifang

    2016-01-01

    The key kinetic barrier to dolomite formation is related to the surface Mg2+-H2O complex, which hinders binding of surface Mg2+ ions to the CO3 2- ions in solution. It has been proposed that this reaction can be catalyzed by dissolved hydrogen sulfide. To characterize the role of dissolved hydrogen sulfide in the dehydration of surface Mg 2+ ions, ab initio simulations based on density functional theory (DFT) were carried out to study the thermodynamics of competitive adsorption of hydrogen sulfide and water on dolomite (104) surfaces from solution. We find that water is thermodynamically more stable on the surface with the difference in adsorption energy of -13.6 kJ/mol (in vacuum) and -12.8 kJ/mol (in aqueous solution). However, aqueous hydrogen sulfide adsorbed on the surface increases the Mg2+-H2O distances on surrounding surface sites. Two possible mechanisms were proposed for the catalytic effects of adsorbed hydrogen sulfide on the anhydrous Ca-Mg-carbonate crystallization at low temperature.

  5. Measurements of hydrogen sulfide (H2S) using PTR-MS: calibration, humidity dependence, inter-comparison and results from field studies in an oil and gas production region

    Science.gov (United States)

    Li, R.; Warneke, C.; Graus, M.; Field, R.; Geiger, F.; Veres, P. R.; Soltis, J.; Li, S.-M.; Murphy, S. M.; Sweeney, C.; Pétron, G.; Roberts, J. M.; de Gouw, J.

    2014-10-01

    Natural gas production is associated with emissions of several trace gases, some of them classified as air toxics. While volatile organic compounds (VOCs) have received much attention, hydrogen sulfide (H2S) can also be of concern due to the known health impacts of exposure to this hazardous air pollutant. Here, we present quantitative, fast time-response measurements of H2S using proton-transfer-reaction mass-spectrometry (PTR-MS) instruments. An ultra-light-weight PTR-MS (ULW-PTR-MS) in a mobile laboratory was operated for measurements of VOCs and H2S in a gas and oil field during the Uintah Basin Winter Ozone Study (UBWOS) 2012 campaign. Measurements of VOCs and H2S by a PTR-MS were also made at the Horse Pool ground site in the Uintah Basin during UBWOS 2013. The H2S measurement by PTR-MS is strongly humidity dependent because the proton affinity of H2S is only slightly higher than that of water. The H2S sensitivity of PTR-MS ranged between 0.6-1.4 ncps ppbv-1 during UBWOS 2013. We compare the humidity dependence determined in the laboratory with in-field calibrations and determine the H2S mixing ratios for the mobile and ground measurements. The PTR-MS measurements at Horse Pool are evaluated by comparison with simultaneous H2S measurements using a PTR time-of-flight MS (PTR-ToF-MS) and a Picarro cavity ring down spectroscopy (CRDS) instrument for H2S / CH4. On average 0.6 ± 0.3 ppbv H2S was present at Horse Pool during UBWOS 2013. The correlation between H2S and methane enhancements suggests that the source of H2S is associated with oil and gas extraction in the basin. Significant H2S mixing ratios of up to 9 ppmv downwind of storage tanks were observed during the mobile measurements. This study suggests that H2S emissions associated with oil and gas production can lead to short-term high levels close to point sources, and elevated background levels away from those sources. In addition, our work has demonstrated that PTR-MS can make reliable measurements of

  6. Measurements of hydrogen sulfide (H2S using PTR-MS: calibration, humidity dependence, inter-comparison and results from field studies in an oil and gas production region

    Directory of Open Access Journals (Sweden)

    R. Li

    2014-06-01

    Full Text Available Natural gas production is associated with emissions of several trace gases, some of them classified as air toxics. While volatile organic compounds (VOCs have received much attention, hydrogen sulfide (H2S can also be of concern due to the known health impacts of exposure to this hazardous air pollutant. Here, we present quantitative, fast time-response measurements of H2S using Proton-Transfer-Reaction Mass-Spectrometry (PTR-MS instruments. An Ultra-Light-Weight PTR-MS (ULW-PTR-MS in a mobile laboratory was operated for measurements of VOCs and H2S in a gas and oil field during the Uintah Basin Winter Ozone Study (UBWOS 2012 campaign. Measurements of VOCs and H2S by a PTR-MS were also made at the Horse Pool ground site in the Uintah Basin during UBWOS 2013. The H2S measurement by PTR-MS is strongly humidity dependent because the proton affinity of H2S is only slightly higher than that of water. The H2S sensitivity of PTR-MS ranged between 0.6–1.4 ncps ppbv−1 (normalized counts per second/parts per billion by volume during UBWOS 2013. We compare the humidity dependence determined in the laboratory with in-field calibrations and determine the H2S mixing ratios for the mobile and ground measurements. The PTR-MS measurements at Horse Pool are evaluated by comparison with simultaneous H2S measurements using a PTR Time-of-Flight MS (PTR-ToF-MS and a Picarro cavity ring down spectroscopy (CRDS instrument for H2S/CH4. On average 0.6 ± 0.3 ppbv H2S was present at Horse Pool during UBWOS 2013. The correlation between H2S and methane enhancements suggests that the source of H2S is associated with oil and gas extraction in the basin. Significant H2S mixing ratios of up to 9 ppmv downwind of storage tanks were observed during the mobile measurements. This study suggests that H2S emissions associated with oil and gas production can lead to short-term high levels close to point sources, and elevated background levels away from those sources. In addition

  7. Allyl m-Trifluoromethyldiazirine Mephobarbital: An Unusually Potent Enantioselective and Photoreactive Barbiturate General Anesthetic

    Energy Technology Data Exchange (ETDEWEB)

    Savechenkov, Pavel Y.; Zhang, Xi; Chiara, David C.; Stewart, Deirdre S.; Ge, Rile; Zhou, Xiaojuan; Raines, Douglas E.; Cohen, Jonathan B.; Forman, Stuart A.; Miller, Keith W.; Bruzik, Karol S. (Harvard-Med); (Mass. Gen. Hosp.); (UIC)

    2012-12-10

    We synthesized 5-allyl-1-methyl-5-(m-trifluoromethyl-diazirynylphenyl)barbituric acid (14), a trifluoromethyldiazirine-containing derivative of general anesthetic mephobarbital, separated the racemic mixture into enantiomers by chiral chromatography, and determined the configuration of the (+)-enantiomer as S by X-ray crystallography. Additionally, we obtained the {sup 3}H-labeled ligand with high specific radioactivity. R-(-)-14 is an order of magnitude more potent than the most potent clinically used barbiturate, thiopental, and its general anesthetic EC{sub 50} approaches those for propofol and etomidate, whereas S-(+)-14 is 10-fold less potent. Furthermore, at concentrations close to its anesthetic potency, R-(-)-14 both potentiated GABA-induced currents and increased the affinity for the agonist muscimol in human {alpha}1{beta}2/3{gamma}2L GABA{sub A} receptors. Finally, R-(-)-14 was found to be an exceptionally efficient photolabeling reagent, incorporating into both {alpha}1 and {beta}3 subunits of human {alpha}1{beta}3 GABAA receptors. These results indicate R-(-)-14 is a functional general anesthetic that is well-suited for identifying barbiturate binding sites on Cys-loop receptors.

  8. Enhanced biocompatibility and wound healing properties of biodegradable polymer-modified allyl 2-cyanoacrylate tissue adhesive.

    Science.gov (United States)

    Lee, Young Ju; Son, Ho Sung; Jung, Gyeong Bok; Kim, Ji Hye; Choi, Samjin; Lee, Gi-Ja; Park, Hun-Kuk

    2015-06-01

    As poly L-lactic acid (PLLA) is a polymer with good biocompatibility and biodegradability, we created a new tissue adhesive (TA), pre-polymerized allyl 2-cyanoacrylate (PACA) mixed with PLLA in an effort to improve biocompatibility and mechanical properties in healing dermal wound tissue. We determined optimal mixing ratios of PACA and PLLA based on their bond strengths and chemical structures analyzed by the thermal gravimetric analysis (TGA) and Fourier transform infrared (FT-IR) spectroscopy. In vitro biocompatibility of the PACA/PLLA was evaluated using direct- and indirect-contact methods according to the ISO-10993 cytotoxicity test for medical devices. The PACA/PLLA have similar or even better biocompatibility than those of commercially available cyanoacrylate (CA)-based TAs such as Dermabond® and Histoacryl®. The PACA/PLLA were not different from those exposed to Dermabond® and Histoacryl® in Raman spectra when biochemical changes of protein and DNA/RNA underlying during cell death were compared utilizing Raman spectroscopy. Histological analysis revealed that incised dermal tissues of rats treated with PACA/PLLA showed less inflammatory signs and enhanced collagen formation compared to those treated with Dermabond® or Histoacryl®. Of note, tissues treated with PACA/PLLA were stronger in the tensile strength compared to those treated with the commercially available TAs. Therefore, taking all the results into consideration, the PACA/PLLA we created might be a clinically useful TA for treating dermal wounds. PMID:25842106

  9. Increased presevation of sliced mozzarella cheese by antimibrobial sachet incorporated with allyl isothiocyanate

    Directory of Open Access Journals (Sweden)

    Ana Clarissa dos Santos Pires

    2009-12-01

    Full Text Available There is an increasing tendency to add natural antimicrobials of plant origin into food. The objective of this work was to develop a microbial sachet incorporated with allyl isothiocyanate (AIT, a volatile compound of plant origin, and to test its efficiency against growth of yeasts and molds, Staphylococcus sp. and psychrotrophic bacteria on sliced mozzarella cheese. Another objective was to quantify the concentration of AIT in the headspace of cheese packaging. A reduction of 3.6 log cycles was observed in yeasts and molds counts in the mozzarella packed with the antimicrobial sachet over 15-day storage time. The sachet also showed an antibacterial effect on Staphylococcus sp., reducing 2.4 log cycles after 12-day storage. Psychrotrophic bacteria species were the most resistant to the antimicrobial action. The highest concentration of AIT (0.08µg.mL-1 inside the active packaging system was observed at the 6-day of storage at 12 ºC ± 2 ºC. At the end of the storage time, AIT concentration decreased to only 10% of the initial concentration. Active packaging containing antimicrobial sachet has a potential use for sliced mozzarella, with molds and yeasts being the most sensitive to the antimicrobial effects.

  10. Allyl functionalized phosphinite and phosphonite ligands: Synthesis, transition metal chemistry and orthopalladation reactions

    Indian Academy of Sciences (India)

    Singappagudem Govindaraju; Guddekoppa S Ananthnag; Susmita Naik; Shaikh M Mobin; Maravanji S Balakrishn

    2012-07-01

    Allyl functionalized phosphinite PPh2(OAr) [Ar=C6H4(-C3H5)] (1) and phosphonite PPh(OAr)2 (2) ligands were prepared by the reactions of 2-allylphenol with PPh2Cl and PPhCl2, respectively. The ruthenium(II) complexes, [Ru(6--cymene)(PPh2(OAr))Cl2] (3) and [Ru(6--cymene)(PPh(OAr)2Cl2)] (4) were obtained by reacting 1 or 2 with [Ru(6--cymene)Cl2]2 in 2:1 molar ratios, respectively. Reactions of 1 or 2 with AuCl(SMe2) gave [Au{PPh2(OAr)}Cl] (5) or [Au{PPh(OAr)2}Cl] (6) in good yield. The palladium complex, [Pd{PPh(OAr)2}2Cl2] (7) was prepared by reacting Pd(COD)Cl2 with 2 in 1:2 molar ratio. The reaction between Pd(COD)Cl2 and 1 yielded a mixture of orthopalladated cis- and trans-[Pd(Ph2P(OAr))Cl]2 (8a and 8b). The treatment of 8 with PPh3 and Ph2PCH2PPh2 resulted in the cleavage of chloro bridge to give respectively, [Ph2(OAr)PPd(PPh3)Cl] (9) and [Ph2(ArO)PPd(2-dppm)]OTf (10). Single crystal X-ray structure of the ruthenium complex 3 is described.

  11. Photocatalytic Activities of Copper Doped Cadmium Sulfide Microspheres Prepared by a Facile Ultrasonic Spray-Pyrolysis Method

    OpenAIRE

    Jinzhan Su; Tao Zhang; Yufeng Li; Yubin Chen; Maochang Liu

    2016-01-01

    Ultrasonic spray pyrolysis is a superior method for preparing and synthesizing spherical particles of metal oxide or sulfide semiconductors. Cadmium sulfide (CdS) photocatalysts with different sizes and doped-CdS with different dopants and doping levels have been synthesized to study their properties of photocatalytic hydrogen production from water. The CdS photocatalysts were characterized with scanning electron microscopy (SEM), X-ray fluorescence-spectrometry (XRF), UV-Vis absorption spect...

  12. Improving the sensitivity of the ZnO gas sensor to dimethyl sulfide

    Science.gov (United States)

    Suchorska-Woźniak, P.; Nawrot, W.; Rac, O.; Fiedot, M.; Teterycz, H.

    2016-01-01

    This study was focused on how to improve the gas sensing properties of resistive gas sensors based on zinc oxide to dimethyl sulfide (DMS). The aim of this research was to investigate possible ways of improvement detection of dimethyl sulfide, such as volume doping with synthesized gold nanoparticles or applying sepiolite passive filter. The addition of noble metal into the gas sensing layer is a widely known method of increasing gas sensor response. Sepiolite is a clay mineral with highly porous structure consisting of nanotubes few micrometers long and water absorption abilities. In this work thick-film resistive gas sensors based on zinc oxide were made (pure ZnO, modified by gold nanoparticles, with the addition of filter) and tested for low concentration (2 ppm) of dimethyl sulfide. The sensitivities to DMS of developed sensors were compared. Attention was paid to the analysis of the impact of high humidity (90% RH) on the sensor time response.

  13. Characterization of AISI 1005 corrosion films grown under cyclic voltammetry of low sulfide ion concentrations

    International Nuclear Information System (INIS)

    Highlights: •The corrosion of AISI 1005 in sulfide solutions was investigated. •The mechanism of film growth on carbon steel in sulfide solutions was studied. •Film growth was characterized using SEM, EDX, XRD and Mössbauer spectroscopy. •Growth of AISI 1005 corrosion films under cyclic voltammetry. -- Abstract: The mechanism of AISI 1005 corrosion in sulfide ion solutions has been investigated using cyclic voltammetry, electrochemical impedance spectroscopy, X-ray diffraction (XRD) and Mössbauer spectroscopy (MS). The proposed mechanism occurs with the initial formation of oxygenated ferrous species followed by adsorption of HS− species, precipitation of iron monosulfides and their partial conversion to bisulfide iron. This mechanism was demonstrated by XRD results that revealed Fe-O and Fe-S phases and by MS results that detected pyrite as the major proportion (94%) of the iron species in the corrosion product

  14. Sulfide Intrusion and Detoxification in the Seagrass Zostera marina.

    Directory of Open Access Journals (Sweden)

    Harald Hasler-Sheetal

    Full Text Available Gaseous sulfide intrusion into seagrasses growing in sulfidic sediments causes little or no harm to the plant, indicating the presence of an unknown sulfide tolerance or detoxification mechanism. We assessed such mechanism in the seagrass Zostera marina in the laboratory and in the field with scanning electron microscopy coupled to energy dispersive X-ray spectroscopy, chromatographic and spectrophotometric methods, and stable isotope tracing coupled with a mass balance of sulfur compounds. We found that Z. marina detoxified gaseous sediment-derived sulfide through incorporation and that most of the detoxification occurred in underground tissues, where sulfide intrusion was greatest. Elemental sulfur was a major detoxification compound, precipitating on the inner wall of the aerenchyma of underground tissues. Sulfide was metabolized into thiols and entered the plant sulfur metabolism as well as being stored as sulfate throughout the plant. We conclude that avoidance of sulfide exposure by reoxidation of sulfide in the rhizosphere or aerenchyma and tolerance of sulfide intrusion by incorporation of sulfur in the plant are likely major survival strategies of seagrasses in sulfidic sediments.

  15. Pressure Effects on Product Channels of the Allyl Radical Reactions; C3H5+C3H5 and C3H5+CH3

    Science.gov (United States)

    Halpern, J. B.; N'Doumi, M.; Fahr, A.

    2011-12-01

    Relatively large hydrocarbon molecules (C4, C6 and larger) have been detected in several planetary environments. The mechanism for the formation of such large molecular species and detailed mechanism for their potential destruction are not well understood and are of considerable current interest. Previously we have studied the kinetics and product channels of small unsaturated hydrocarbon radical (C2 and C3s) reactions relevant to planetary atmospheric modeling. Reactions of C2 radicals (such as vinyl, H2CCH and ethynyl C2H) and C3 radicals (such as propargyl, HCCCH2) can affect the abundances of a large number of stable observable C3, C4, C5, C6 and larger molecules, including linear, aromatic and even poly aromatic molecules. Pressure-dependent product yields have been determined experimentally for the self- and cross-radical reactions performed at 298 K and at pressures between ~4 Torr (0.5 kPa) and 760 Torr (101 kPa). Final reaction products were quantitatively determined using a gas chromatograph with mass spectrometry/flame ionization detection (GC/MS/FID). In some cases complementary computational studies extended the pressure and temperature range of the experiments and provided valuable information on the complex reaction mechanisms. Theses studies provide a systematic framework so that important energetic and structural parameters for radical-radical reactions can be assessed. Here we report recent results for the allyl radical reactions H2CCCH3+ H2CCCH3 and H2CCCH3+CH3. For the allyl radical self-reaction, at high pressures the "head -to-head", combination channel forming 1,5-hexadiene is dominant with a combination/disproportionation = 1,5-hexadiene/propyne ratio of about 24 at 500 Torr (67 kPa, T=298K). At low pressures the ratio is substantially reduced to about 1.2 (at 0.3 kPa) and other major products are observed including allene, propene, 1-butene and propyne.

  16. The Evolution of Sulfide Tolerance in the Cyanobacteria

    Science.gov (United States)

    Miller, Scott R.; Bebout, Brad M.; DeVincenzi, Donald L. (Technical Monitor)

    2000-01-01

    Understanding how the function of extant microorganisms has recorded both their evolutionary histories and their past interactions with the environment is a stated goal of astrobiology. We are taking a multidisciplinary approach to investigate the diversification of sulfide tolerance mechanisms in the cyanobacteria, which vary both in their degree of exposure to sulfide and in their capacity to tolerate this inhibitor of photosynthetic electron transport. Since conditions were very reducing during the first part of Earth's history and detrital sulfides have been found in Archean sediments, mechanisms conferring sulfide tolerance may have been important for the evolutionary success of the ancestors of extant cyanobacteria. Two tolerance mechanisms have been identified in this group: (1) resistance of photosystem II, the principal target of sulfide toxicity; and (2) maintenance of the ability to fix carbon despite photosystem II inhibition by utilizing sulfide as an electron donor in photosystem I - dependent, anoxygenic photosynthesis. We are presently collecting comparative data on aspects of sulfide physiology for laboratory clones isolated from a variety of habitats. These data will be analyzed within a phylogenetic framework inferred from molecular sequence data collected for these clones to test how frequently different mechanisms of tolerance have evolved and which tolerance mechanism evolved first. In addition, by analyzing these physiological data together with environmental sulfide data collected from our research sites using microelectrodes, we can also test whether the breadth of an organism's sulfide tolerance can be predicted from the magnitude of variation in environmental sulfide concentration it has experienced in its recent evolutionary past and whether greater average sulfide concentration and/or temporal variability in sulfide favors the evolution of a particular mechanism of sulfide tolerance.

  17. Iron-sulfide redox flow batteries

    Science.gov (United States)

    Xia, Guan-Guang; Yang, Zhenguo; Li, Liyu; Kim, Soowhan; Liu, Jun; Graff, Gordon L

    2013-12-17

    Iron-sulfide redox flow battery (RFB) systems can be advantageous for energy storage, particularly when the electrolytes have pH values greater than 6. Such systems can exhibit excellent energy conversion efficiency and stability and can utilize low-cost materials that are relatively safer and more environmentally friendly. One example of an iron-sulfide RFB is characterized by a positive electrolyte that comprises Fe(III) and/or Fe(II) in a positive electrolyte supporting solution, a negative electrolyte that comprises S.sup.2- and/or S in a negative electrolyte supporting solution, and a membrane, or a separator, that separates the positive electrolyte and electrode from the negative electrolyte and electrode.

  18. Iron-sulfide redox flow batteries

    Energy Technology Data Exchange (ETDEWEB)

    Xia, Guanguang; Yang, Zhenguo; Li, Liyu; Kim, Soowhan; Liu, Jun; Graff, Gordon L

    2016-06-14

    Iron-sulfide redox flow battery (RFB) systems can be advantageous for energy storage, particularly when the electrolytes have pH values greater than 6. Such systems can exhibit excellent energy conversion efficiency and stability and can utilize low-cost materials that are relatively safer and more environmentally friendly. One example of an iron-sulfide RFB is characterized by a positive electrolyte that comprises Fe(III) and/or Fe(II) in a positive electrolyte supporting solution, a negative electrolyte that comprises S.sup.2- and/or S in a negative electrolyte supporting solution, and a membrane, or a separator, that separates the positive electrolyte and electrode from the negative electrolyte and electrode.

  19. Oxidation of Reduced Sulfur Species: Carbonyl Sulfide

    DEFF Research Database (Denmark)

    Glarborg, Peter; Marshall, Paul

    2013-01-01

    A detailed chemical kinetic model for oxidation of carbonyl sulfide (OCS) has been developed, based on a critical evaluation of data from the literature. The mechanism has been validated against experimental results from batch reactors, flow reactors, and shock tubes. The model predicts satisfact......A detailed chemical kinetic model for oxidation of carbonyl sulfide (OCS) has been developed, based on a critical evaluation of data from the literature. The mechanism has been validated against experimental results from batch reactors, flow reactors, and shock tubes. The model predicts...... satisfactorily oxidation of OCS over a wide range of stoichiometric air–fuel ratios (0.5 ≤λ≤7.3), temperatures (450–1700 K), and pressures (0.02–3.0 atm) under dry conditions. The governing reaction mechanisms are outlined based on calculations with the kinetic model. The oxidation rate of OCS is controlled...

  20. Modeling the Effect of Dissolved Hydrogen Sulfide on Mg2+-water Complex on Dolomite {104} Surfaces

    OpenAIRE

    Shen, Zhizhang; Liu, Yun; Brown, Philip E; Szlufarska, Izabela; Xu, Huifang

    2016-01-01

    The key kinetic barrier to dolomite formation is related to the surface Mg2+-H2O complex, which hinders binding of surface Mg2+ ions to the CO3 2- ions in solution. It has been proposed that this reaction can be catalyzed by dissolved hydrogen sulfide. To characterize the role of dissolved hydrogen sulfide in the dehydration of surface Mg 2+ ions, ab initio simulations based on density functional theory (DFT) were carried out to study the thermodynamics of competitive adsorption of hydrogen s...

  1. Zinc-rich clays in supergene non-sulfide zinc deposits

    OpenAIRE

    Choulet, Flavien; Buatier, M.; Barbanson, Luc; Guégan, Régis; Ennaciri, A.

    2015-01-01

    The nature and the origin of zinc clays are poorly understood. With the example of the Bou Arhous Zn-Pb ore deposit in the Moroccan High Atlas, this study presents new data for the mineralogical and chemical characterization of barren and zinc clays associated with non-sulfide zinc ores. In the field, white to ocher granular clays are associated with willemite (Zn2SiO4), while red clays fill karst-related cavities cutting across the non-sulfide ore bodies. Red clays (kaolinite, chlorite, illi...

  2. Hydrolysis of Carbonyl Sulfide in Binary Mixture of Diethylene Glycol Diethyl Ether and Water

    Institute of Scientific and Technical Information of China (English)

    李新学; 刘迎新; 魏雄辉

    2005-01-01

    The solubility and hydrolysis of carbonyl sulfide in binary mixture of diethylene glycol diethyl ether and water are studied as a function of composition. The use of an aqueous solution of diethylene glycol diethyl ether enhances the solubility and hydrolysis rate of carbonyl sulfide compared with that in pure water. The composition of the mixture with maximum hydrolysis rate varies with temperature. The thermophysical properties including density, viscosity, and surface tension as a function of composition at 20℃ under atmospheric pressure as well as liquid-liquid equilibrium (LLE) data over the temperature range from 28℃ to 90℃ are also measured for the binary mixture.

  3. Activity of Transition Metal Sulfides Supported on Al2O3,

    OpenAIRE

    Kaluža, L. (Luděk)

    2015-01-01

    Sulfided conventional transition metals Co, Ni, Mo, and W and noble metals Rh, Pd, Ir, Pt, and Re deposited over conventional support c-Al2O3 (SBET = 262 m2g-1), and unconventional supports TiO2 (anatase, SBET = 140 m2- g-1) and ZrO2 (baddeleyite, SBET = 108 m2g-1) were studied in the parallel hydrodesulfurization of 1-benzothiophene (HDS) and hydrogenation of 1-methylcyclohex- 1-ene (o-HYD) at 360 Cand 1.6 MPa. Mo, W, Co, and Ni sulfided catalysts exhibited relatively low activity in bot...

  4. On the inhibition of hydrogen sulfide corrosion of steel with Schiff Bases

    International Nuclear Information System (INIS)

    The number of the Schiff bases(above 20 compounds) is synthesized. Their impact on the kinetics of electrochemical reactions and steel corrosion behaviour in the two-phase systems electrolyte - hydrocarbon containing H2S, is studied. It is shown, that azomethines, synthesized by the Schiff reaction from aldehydes and aliphatic amines, may serve as water-soluble inhibitors in these systems. The efficiency of steel corrosion protection against hydrogen sulfide corrosion through azomethines depends on their chemical structure and pH media. The effective water-soluble inhibitor of the hydrogen sulfide corrosion - IFKhAN-62 - is developed

  5. Subsurface heaters with low sulfidation rates

    Energy Technology Data Exchange (ETDEWEB)

    John, Randy Carl; Vinegar, Harold J

    2013-12-10

    A system for heating a hydrocarbon containing formation includes a heater having an elongated ferromagnetic metal heater section. The heater is located in an opening in a formation. The heater section is configured to heat the hydrocarbon containing formation. The exposed ferromagnetic metal has a sulfidation rate that goes down with increasing temperature of the heater, when the heater is in a selected temperature range.

  6. Hydrogen sulfide prodrugs-a review.

    Science.gov (United States)

    Zheng, Yueqin; Ji, Xingyue; Ji, Kaili; Wang, Binghe

    2015-09-01

    Hydrogen sulfide (H2S) is recognized as one of three gasotransmitters together with nitric oxide (NO) and carbon monoxide (CO). As a signaling molecule, H2S plays an important role in physiology and shows great potential in pharmaceutical applications. Along this line, there is a need for the development of H2S prodrugs for various reasons. In this review, we summarize different H2S prodrugs, their chemical properties, and some of their potential therapeutic applications. PMID:26579468

  7. Hydrogen sulfide prodrugs—a review

    Directory of Open Access Journals (Sweden)

    Yueqin Zheng

    2015-09-01

    Full Text Available Hydrogen sulfide (H2S is recognized as one of three gasotransmitters together with nitric oxide (NO and carbon monoxide (CO. As a signaling molecule, H2S plays an important role in physiology and shows great potential in pharmaceutical applications. Along this line, there is a need for the development of H2S prodrugs for various reasons. In this review, we summarize different H2S prodrugs, their chemical properties, and some of their potential therapeutic applications.

  8. Efficiently Dispersing Carbon Nanotubes in Polyphenylene Sulfide

    OpenAIRE

    Sommer, Kevin M; Pipes, R. Byron

    2013-01-01

    Thermal plastics are replacing conventional metals in the aerospace, sporting, electronics, and other industries. Thermal plastics are able to withstand relatively high temperatures, have good fatigue properties, and are lighter than metals. Unfortunately, they are not very electrically conductive. However, adding carbon nanotubes to thermal plastics such as polyphenylene sulfide (PPS) can drastically increase the plastic's conductivity at a low weight percent of nanotubes called the percolat...

  9. CuCl-Catalyzed Aerobic Oxidation of Allylic and Propargylic Alcohols to Aldehydes or Ketones with 1 : 1 Combination of Phenanthroline and Bipyridine as the Ligandst%CuCl-Catalyzed Aerobic Oxidation of Allylic and Propargylic Alcohols to Aldehydes or Ketones with 1 : 1 Combination of Phenanthroline and Bipyridine as the Ligandst

    Institute of Scientific and Technical Information of China (English)

    刘宇; 麻生明

    2012-01-01

    We developed a modified protocol for the oxidation of 2,3-allenyl alcohols using CuCI with l : 1 combination of phenanthroline and bipyridine as the catalyst. To further investigate the applicability of this system, other types of alcohols such as allylic and propargylic alcohols have been tested: we found that both allylic and propargylic alcohols may be oxidized to the corresponding aldehydes or ketones using molecular oxygen in air as the oxidant with moderate to excellent yields.

  10. Investigation of the O+allyl addition/elimination reaction pathways from the OCH(2)CHCH(2) radical intermediate.

    Science.gov (United States)

    Fitzpatrick, Benjamin L; Lau, Kai-Chung; Butler, Laurie J; Lee, Shih-Huang; Lin, Jim Jr-Min

    2008-08-28

    These experiments study the preparation of and product channels resulting from OCH(2)CHCH(2), a key radical intermediate in the O+allyl bimolecular reaction. The data include velocity map imaging and molecular beam scattering results to probe the photolytic generation of the radical intermediate and the subsequent pathways by which the radicals access the energetically allowed product channels of the bimolecular reaction. The photodissociation of epichlorohydrin at 193.3 nm produces chlorine atoms and c-OCH(2)CHCH(2) radicals; these undergo a facile ring opening to the OCH(2)CHCH(2) radical intermediate. State-selective resonance-enhanced multiphoton ionization (REMPI) detection resolves the velocity distributions of ground and spin-orbit excited state chlorine independently, allowing for a more accurate determination of the internal energy distribution of the nascent radicals. We obtain good agreement detecting the velocity distributions of the Cl atoms with REMPI, vacuum ultraviolet (VUV) photoionization at 13.8 eV, and electron bombardment ionization; all show a bimodal distribution of recoil kinetic energies. The dominant high recoil kinetic energy feature peaks near 33 kcalmol. To elucidate the product channels resulting from the OCH(2)CHCH(2) radical intermediate, the crossed laser-molecular beam experiment uses VUV photoionization and detects the velocity distribution of the possible products. The data identify the three dominant product channels as C(3)H(4)O (acrolein)+H, C(2)H(4)+HCO (formyl radical), and H(2)CO (formaldehyde)+C(2)H(3). A small signal from C(2)H(2)O (ketene) product is also detected. The measured velocity distributions and relative signal intensities at me=27, 28, and 29 at two photoionization energies show that the most exothermic product channel, C(2)H(5)+CO, does not contribute significantly to the product branching. The higher internal energy onset of the acrolein+H product channel is consistent with the relative barriers en route to

  11. Investigation of the O+allyl addition/elimination reaction pathways from the OCH2CHCH2 radical intermediate

    International Nuclear Information System (INIS)

    These experiments study the preparation of and product channels resulting from OCH2CHCH2, a key radical intermediate in the O+allyl bimolecular reaction. The data include velocity map imaging and molecular beam scattering results to probe the photolytic generation of the radical intermediate and the subsequent pathways by which the radicals access the energetically allowed product channels of the bimolecular reaction. The photodissociation of epichlorohydrin at 193.3 nm produces chlorine atoms and c-OCH2CHCH2 radicals; these undergo a facile ring opening to the OCH2CHCH2 radical intermediate. State-selective resonance-enhanced multiphoton ionization (REMPI) detection resolves the velocity distributions of ground and spin-orbit excited state chlorine independently, allowing for a more accurate determination of the internal energy distribution of the nascent radicals. We obtain good agreement detecting the velocity distributions of the Cl atoms with REMPI, vacuum ultraviolet (VUV) photoionization at 13.8 eV, and electron bombardment ionization; all show a bimodal distribution of recoil kinetic energies. The dominant high recoil kinetic energy feature peaks near 33 kcal/mol. To elucidate the product channels resulting from the OCH2CHCH2 radical intermediate, the crossed laser-molecular beam experiment uses VUV photoionization and detects the velocity distribution of the possible products. The data identify the three dominant product channels as C3H4O (acrolein)+H, C2H4+HCO (formyl radical), and H2CO (formaldehyde)+C2H3. A small signal from C2H2O (ketene) product is also detected. The measured velocity distributions and relative signal intensities at m/e=27, 28, and 29 at two photoionization energies show that the most exothermic product channel, C2H5+CO, does not contribute significantly to the product branching. The higher internal energy onset of the acrolein+H product channel is consistent with the relative barriers en route to each of these product channels

  12. Use of ferric sulfate: acid media for the desulfurization of model compounds of coal. [Dibenzothiophene, diphenyl sulfide, di-n-butyl sulfide

    Energy Technology Data Exchange (ETDEWEB)

    Clary, L.R.; Vermeulen, T.; Lynn, S.

    1980-12-01

    The objective of this work has been to investigate the ability of ferric sulfate-acid leach systems to oxidize the sulfur in model compounds of coal. Ferric iron-acid leach systems have been shown to be quite effective at removal of inorganic sulfur in coal. In this study, the oxidative effect of ferric iron in acid-leach systems was studied using dibenzothiophene, diphenyl sulfide, and di-n-butyl sulfide as models of organic sulfur groups in coal. Nitrogen and oxygen, as well as various transition metal catalysts and oxidants, were utilized in this investigation. Dibenzothiophene was found to be quite refractory to oxidation, except in the case where metavanadate was added, where it appears that 40% oxidation to sulfone could have occurred per hour at 150/sup 0/C and mild oxygen pressure. Diphenyl sulfide was selectively oxidized to sulfoxide and sulfone in an iron and oxygen system. Approximately 15% conversion to sulfone occurred per hour under these conditions. Some of the di-n-butyl sulfide was cracked to 1-butene and 1-butanethiol under similar conditions. Zinc chloride and ferric iron were used at 200/sup 0/C in an attempt to desulfonate dibenzothiophene sulfone, diphenyl sulfone, and di-n-butyl sulfone. Di-n-butyl sulfone was completely desulfurized on one hour and fragmented to oxidized parafins, while dibenzothiophene sulfone and diphenyl sulfone were unaffected. These results suggest that an iron-acid leach process could only selectively oxidize aryl sulfides under mild conditions, representing only 20% of the organic sulfur in coal (8% of the total sulfur). Removal through desulfonation once selective sulfur oxidation had occurred was only demonstrated for alkyl sulfones, with severe oxidation of the fragmented paraffins also occurring in one hour.

  13. Sulfide-oxidizing bacteria establishment in an innovative microaerobic reactor with an internal silicone membrane for sulfur recovery from wastewater.

    Science.gov (United States)

    Valdés, F; Camiloti, P R; Rodriguez, R P; Delforno, T P; Carrillo-Reyes, J; Zaiat, M; Jeison, D

    2016-06-01

    A novel bioreactor, employing a silicone membrane for microaeration, was studied for partial sulfide oxidation to elemental sulfur. The objective of this study was to assess the feasibility of using an internal silicone membrane reactor (ISMR) to treat dissolved sulfide and to characterize its microbial community. The ISMR is an effective system to eliminate sulfide produced in anaerobic reactors. Sulfide removal efficiencies reached 96 % in a combined anaerobic/microaerobic reactor and significant sulfate production did not occur. The oxygen transfer was strongly influenced by air pressure and flow. Pyrosequencing analysis indicated various sulfide-oxidizing bacteria (SOB) affiliated to the species Acidithiobacillus thiooxidans, Sulfuricurvum kujiense and Pseudomonas stutzeri attached to the membrane and also indicated similarity between the biomass deposited on the membrane wall and the biomass drawn from the material support, supported the establishment of SOB in an anaerobic sludge under microaerobic conditions. Furthermore, these results showed that the reactor configuration can develop SOB under microaerobic conditions and can improve and reestablish the sulfide conversion to elemental sulfur. PMID:27003697

  14. 长坡选矿厂锌浮选尾矿硫砷分离试验研究%Experimental study on the separation of pyrite and arsenopyrite for the tailings of zinc sulfides flotation in Changpo plant

    Institute of Scientific and Technical Information of China (English)

    周德炎; 陈志文

    2012-01-01

    In Changpo plant, the arsenic-sulfur minerals were associated with each other and part minerals were not yet hberated m the tailings of zinc sulfides flotation. According to this problem, a new flowsheet was proposed that bulk flotation was firstly adopted, and then the sulfides concentrate was processed for the separation of arsenic-sulfur minerals. In this experiment, a combined agent of hydrogen peroxide and sodium humate (1:1) was used as an arsenic depressant. The results showed when the depressant dosage was 900g/t, desirable indexes could be achieved that the grade and recovery of sulfide concentrate were respectively 44.86% and 87.88%, and the arsenic content could be reduced to below 1%.%针对长坡选矿厂锌浮选尾矿硫砷矿物相互伴生且部分矿物未单体解离的特点,考虑全浮硫化矿,全浮精矿再硫砷分离的原则流程,在硫砷浮选分离过程中采用过氧化氢与腐殖酸钠1:1药剂组合抑制砷矿物,在用量仅为900g/t条件下,硫精矿品位达到44.86%,回收率达到87.88%,硫精矿中砷含量可降低到1%以下。

  15. STUDY ON BULK FLOTATION AND SEPARATION OF MOLYBDENUM AND COPPER IN A COPPER-MOLYBDENUM-SULFIDE POLYMETALLIC ORE%某钼铜硫多金属矿钼铜混合浮选分离研究

    Institute of Scientific and Technical Information of China (English)

    郭月琴; 孙志勇; 吴天骄; 赵笑益

    2014-01-01

    对某铜钼硫多金属矿进行了选矿试验。采用钼铜混合浮选再分离工艺流程,在原矿含 Mo 0.17%、Cu 0.137%、S 5.36%、Pb 0.067%的条件下,获得了含钼49.26%、钼回收率82.66%的钼精矿及含铜15.45%、铜回收率53.52%的铜精矿。实现了钼铜硫矿物与脉石及钼铜硫矿物之间的有效分离,获得了良好的技术指标。%The beneficiation experiment in a copper-molybdenum-sulfide polymetallic ore was done.The molyb-denum copper bulk flotation and separation process was adopted,with the raw ore containing Mo 0.17%,Cu 0.137%,S 5.36%,Pb 0.067%,molybdenum concentrate containing 49.26%molybdenum,the recovery rate of molybdenum 82.66% ,and copper concentrate containing copper 15.45% and copper recovery rate 53.52% has gotten.The effective separation between molybdenum copper sulfide minerals ,gangue and molybdenum copper sulfide minerals was realized and the good technical indexes was obtained.

  16. Analytical modeling of localized surface plasmon resonance in heterostructure copper sulfide nanocrystals

    International Nuclear Information System (INIS)

    Localized surface plasmon resonance (LSPR) in semiconductor nanocrystals is a relatively new field of investigation that promises greater tunability of plasmonic properties compared to metal nanoparticles. A novel process by which the LSPR in semiconductor nanocrystals can be altered is through heterostructure formation arising from solution-based cation exchange. Herein, we describe the development of an analytical model of LSPR in heterostructure copper sulfide-zinc sulfide nanocrystals synthesized via a cation exchange reaction between copper sulfide (Cu1.81S) nanocrystals and Zn ions. The cation exchange reaction produces dual-interface, heterostructure nanocrystals in which the geometry of the copper sulfide phase can be tuned from a sphere to a thin disk separating symmetrically-grown sulfide (ZnS) grains. Drude model electronic conduction and Mie-Gans theory are applied to describe how the LSPR wavelength changes during cation exchange, taking into account the morphology evolution and changes to the local permittivity. The results of the modeling indicate that the presence of the ZnS grains has a significant effect on the out-of-plane LSPR mode. By comparing the results of the model to previous studies on solid-solid phase transformations of copper sulfide in these nanocrystals during cation exchange, we show that the carrier concentration is independent of the copper vacancy concentration dictated by its atomic phase. The evolution of the effective carrier concentration calculated from the model suggests that the out-of-plane resonance mode is dominant. The classical model was compared to a simplified quantum mechanical model which suggested that quantum mechanical effects become significant when the characteristic size is less than ∼8 nm. Overall, we find that the analytical models are not accurate for these heterostructured semiconductor nanocrystals, indicating the need for new model development for this emerging field

  17. Simultaneous removal of sulfide, nitrate and acetate: Kinetic modeling

    International Nuclear Information System (INIS)

    Biological removal of sulfide, nitrate and chemical oxygen demand (COD) simultaneously from industrial wastewaters to elementary sulfur (S0), N2, and CO2, or named the denitrifying sulfide (DSR) process, is a cost effective and environmentally friendly treatment process for high strength sulfide and nitrate laden organic wastewater. Kinetic model for the DSR process was established for the first time on the basis of Activated Sludge Model No. 1 (ASM1). The DSR experiments were conducted at influent sulfide concentrations of 200-800 mg/L, whose results calibrate the model parameters. The model correlates well with the DSR process dynamics. By introducing the switch function and the inhibition function, the competition between autotrophic and heterotrophic denitrifiers is quantitatively described and the degree of inhibition of sulfide on heterotrophic denitrifiers is realized. The model output indicates that the DSR reactor can work well at 0.5 1000 mg/L influent sulfide, however, the DSR system will break down.

  18. Synthesis, molecular modeling and biological evaluation of novel 2-allyl amino 4-methyl sulfanyl butyric acid as α-amylase and α-glucosidase inhibitor

    Science.gov (United States)

    Balan, Kannan; Perumal, Perumal; Sundarabaalaji, Narayanan; Palvannan, Thayumanavan

    2015-02-01

    In the present study 2-allyl amino 4-methyl sulfanyl butyric acid (AMSB) was synthesized in good yield. AMSB was characterized by Fourier transforms infrared spectroscopy (FTIR), Nuclear magnetic resonance (NMR) (1H and 13C) and Liquid chromatography mass spectrometry (LCMS). The radical scavenging activity and reducing power assay of AMSB was assessed using 1-1-diphenyl 2-picryl hydrazyl (DPPH), 2,2‧-azino-bis (3-ethyl benzothiazoline-6-sulfonic acid) (ABTS) and ferric ion reducing antioxidant power assay (FRAP) and was found to be 44.1, 34.71 and 41.7 μg/ml respectively. The compound showed effective inhibition against α-amylase and α-glucosidase. AMSB was identified to be a reversible mixed noncompetitive inhibitor of α-amylase and α-glucosidase. The molecular docking study was carried out to evaluate the specific groove binding properties and affords valuable information of AMSB binding mode in the active site of α-glucosidase the study may lead to the which leads to the rational design of new class of antidiabetic drugs targeting α-glucosidase based on AMSB in near future.

  19. Studies for the synthesis of marine natural products*

    OpenAIRE

    Williams, David R.; Walsh, Martin J.; Claeboe, Christopher D.; Zorn, Nicolas

    2009-01-01

    The process of allylic transposition in SE′ reactions is a significant construct for synthesis. The flexibility of a variety of allylation strategies provides for the rational design of pathways to a diverse array of complex targets. Our recent studies of SE′ reactions will examine issues of stereoselectivity and efficiency in the context of applications toward the synthesis of marine natural products such as the xenicane diterpenes, which feature the strained E-cyclononene ring system, and p...

  20. Effect of dissolved oxygen on elemental sulfur generation in sulfide and nitrate removal process: characterization, pathway, and microbial community analysis.

    Science.gov (United States)

    Wang, Xiaowei; Zhang, Yu; Zhang, Tingting; Zhou, Jiti

    2016-03-01

    Microaerobic bioreactor treatment for enriched sulfide and nitrate has been demonstrated as an effective strategy to improve the efficiencies of elemental sulfur (S(0)) generation, sulfide oxidation, and nitrate reduction. However, there is little detailed information for the effect and mechanism of dissolved oxygen (DO) on the variations of microbial community in sulfur generation, sulfide oxidation, and nitrate reduction systems. Polymerase chain reaction denaturing gradient gel electrophoresis (PCR-DGGE) was employed to evaluate the variations of microbial community structures in a sulfide oxidation and nitrate reduction reactor under different DO conditions (DO 0-0.7 mg · L(-1)). Experimental results revealed that the activity of sulfide-oxidizing bacteria (SOB) and nitrate-reducing bacteria (NRB) could be greatly stimulated in 0.1-0.3 mg-DO · L(-1). However, when the DO concentration was further elevated to more than 0.5 mg · L(-1), the abundance of NRB was markedly decreased, while the heterotrophic microorganisms, especially carbon degradation species, were enriched. The reaction pathways for sulfide and nitrate removal under microaerobic conditions were also deduced by combining batch experiments with functional species analysis. It was likely that the oxidation of sulfide to sulfur could be performed by both aerobic heterotrophic SOB and sulfur-based autotrophic denitrification bacteria with oxygen and nitrate as terminal electron acceptor, respectively. The nitrate could be reduced to nitrite by both autotrophic and heterotrophic denitrification, and then the generated nitrite could be completely converted to nitrogen gas via heterotrophic denitrification. This study provides new insights into the impacts of microaerobic conditions on the microbial community functional structures of sulfide-oxidizing, nitrate-reducing, and sulfur-producing bioreactors, which revealing the potential linkage between functional microbial communities and