Automatic Carbon,Hydrogen, Nitrogen,Sulfur Analyzer Ciiemistry of Sulfur Reactions

Abstract

An automatic analyzer for the simultaneous microdetermination of carbon, hydrogen, nitrogen, and sulfur is described. The method is based on the uncatalyzed, dynamic, flash-combustion of the sample in an oxygen/helium atmosphere in a quartz tube. Separation of the combustion gases, N₂, CO₂, SO₂, and H₂O is accomplished by using gas chromatography and a thermal conductivity detector. Reactions of SO₂ formation are given in detail.     

Sampling and Analysis of Odorous Compounds in Water Treatment Plants

Abstract

The following analytical method has been used to identify some odorous compounds in the air of the water treatment plant Werdholzli, Zurich: sampling of contaminated air with the help of activated carbon, desorption by the solvents carbon disulphide and methylene chloride, separation of the carbon disulfide extract into a polar and a nonpolar fraction by adsorption column chromatography on silica. Hereafter gaschromatographic analysis of the polar fraction on glass capillary column (Ucon HB 5100); detection and identification were achieved by flame ionisation, thermoionic nitrogen selective detector and computerized mass spectrometry (Finnigan 3200 F, data system 6110).

The results show the presence of sulfur compounds: thiophenes, thiazoles; nitrogen compounds: pyrazines; oxygen compounds: phenols, alcohols and some unsatured hydrocarbons. The malodorous compounds were sulfur and nitrogen compounds in the range of 0.01-0.1 ppm.     

SuFEx Chemistry of Thionyl Tetrafluoride (SOF4) with Organolithium Nucleophiles: Synthesis of Sulfonimidoyl Fluorides,Sulfoximines, Sulfonimidamides,and Sulfonimidates

Thionyl tetrafluoride (SOF₄) is a valuable connective gas for sulfur fluoride exchange (SuFEx) click chemistry that enables multidimensional linkages to be created via sulfur–oxygen and sulfur–nitrogen bonds. Herein, we expand the available SuFEx chemistry of SOF₄ to include organolithium nucleophiles, and demonstrate, for the first time, the controlled projection of sulfur–carbon links at the sulfur center of SOF₄‐derived iminosulfur oxydifluorides (R¹−N=SOF₂). This method provides rapid and modular access to sulfonimidoyl fluorides (R¹−N=SOFR²), another array of versatile SuFEx connectors with readily tunable reactivity of the S−F handle. Divergent connections derived from these valuable sulfonimidoyl fluoride units are also demonstrated, including the synthesis of sulfoximines, sulfonimidamides, and sulfonimidates.     

SuFEx Chemistry of Thionyl Tetrafluoride (SOF4) with Organolithium Nucleophiles: Synthesis of Sulfonimidoyl Fluorides,Sulfoximines, Sulfonimidamides,and Sulfonimidates

Thionyl tetrafluoride (SOF₄) is a valuable connective gas for sulfur fluoride exchange (SuFEx) click chemistry that enables multidimensional linkages to be created via sulfur–oxygen and sulfur–nitrogen bonds. Herein, we expand the available SuFEx chemistry of SOF₄ to include organolithium nucleophiles, and demonstrate, for the first time, the controlled projection of sulfur–carbon links at the sulfur center of SOF₄‐derived iminosulfur oxydifluorides (R¹?N=SOF₂). This method provides rapid and modular access to sulfonimidoyl fluorides (R¹?N=SOFR²), another array of versatile SuFEx connectors with readily tunable reactivity of the S?F handle. Divergent connections derived from these valuable sulfonimidoyl fluoride units are also demonstrated, including the synthesis of sulfoximines, sulfonimidamides, and sulfonimidates.     

Synthesis,characterization, and crystal structure determination of palladacycles of para-substituted 2-thiobenzylazobenzenes

Bichelated neutral palladacycles (1–3), [Pd(L)Cl], were synthesized from reaction of the new potential tridentate (C,N,S) ligands, 2-thiobenzylazobenzene (L₁), 4′-methyl-2-thiobenzylazobenzene (L₂), and 4′-chloro-2-thiobenzylazobenzene (L₃) with sodium tetrachloropalladate(II), Na₂[PdCl₄], in ethanol. The compounds were characterized by elemental analysis, FT-IR, ¹H NMR, UV–visible, and thermogravimetric analysis. The crystal structures of L₂ and 1–3 were determined by single-crystal X-ray diffraction. In 1–3, the geometry around palladium remains almost square planar, coordinated to carbon, nitrogen, and sulfur of the ligand forming a bichelated cyclopalladate complex. The C–H…Cl type intermolecular hydrogen bonds, weak π…π, C–H…π, and van der Waals interactions are believed to be the stabilizing forces for the crystal packing of these palladacycles.     

Controllable Sulfur,Nitrogen Co‐doped Porous Carbon for Ethylbenzene Oxidation: The Role of Nano‐CaCO3

Heteroatom‐doped porous carbon materials have exhibited promising applications in various fields. In this work, sulfur, nitrogen co‐doped carbon materials (SNCs) with abundant pore structure were prepared by pyrolysis of sulfur, nitrogen‐containing porous organic polymers (POPs) mixed with nano‐CaCO₃ at high temperature. Among the resultant materials, SNC‐Ca‐850 possesses a relatively high level of doped heteroatoms and exhibits an excellent catalytic performance for the selective oxidation of benzylic C?H bonds. It is noteworthy that nano‐CaCO₃ increases the doped sulfur content in the synthesized carbon materials to a large extent and impacts the existence modes of sulfur. In addition, it enhances the porous structure and specific surface area of the resultant SNCs significantly. This work provides a viable strategy to promote the doping of sulfur into carbon materials during the pyrolysis process.     

CARBOHYDRATES CONTAINING SULFUR

Abstract

Thioglycosides with sulfur as the glycosidic bridge are naturally occurring. They have been examined chemically and also biochemically wherein they aid in establishment of enzyme activity. Sugars and sugar nucleoside derivatives with sulfur—and sometimes selenium and nitrogen—replacing the ring oxygen show interesting chemistry and are of great potential usefulness in medicine as indicated by initial biochemical investigations. Their value in biochemistry as analogs of natural structures is proving of useful interest. Carbohydrates with sulfur at positions other than at the anomeric carbon or with ring involvement have interesting chemical properties. This review presents a general survey of carbohydrates containing sulfur, of their special methods of synthesis, their special chemical properties and reactions and a very brief review of their biochemistry and potential clinical value.     

AMIDO- AND AMINO-ALKYLATION OF SULFIMIDES,SULFOXIMIDES, AND SULFODIIMIDES

Abstract

Sulfimides, Sulfoximides and Sulfodiimides are polyfunctional compounds with nucleophilic/basic nitrogen and acidic hydrogen adjacent to sulfur. From these Mannich-type-reaction products 1 were prepared. For example, amidomethylation on nitrogen was achieved either directly via three-component condensation (pathway (a) or, after conversion of the S-Imide into the sodium salt by treatment with N-chloromethyl-amides (pathway (b)). With highly reactive methylene-iminium halides pathway (b) provided N-aminomethylated sulfoximides, the stability of which mainly depends on the substituents on sulfur. Surprisingly stable, however, are their monoquaternary salts. These are of pharmaceutical interest with respect to anticholinergic and antihistamine activity, which was found in this series and will briefly be discussed. Of similar interest but spasmolytically less active are C-Mannich-bases of type 2 as well as N-aminoalkylated sulfodiimides 3, which were synthesized by different reaction routes.     

Changes in Reduced Gaseous Sulfur Compounds Collected in Glass Gas Sampling Bulbs

Abstract

Changes which volatile reduced sulfur species (hydrogen sulfide, carbonyl sulfide, methanethiol, dimethyl sulfide and carbon disulfide) undergo in glass gas sampling bulbs were determined as influenced by the balance gas matrix and moisture. Results have shown that differences in reduced sulfur gas concentrations compared with the initial values were less than 5% in each sulfur compounds within 24 hours if the balance gas was dry nitrogen. There was no change in composition if dry air sample was measured within 3 hours. Significant decrease in hydrogen sulfide and methanethiol concentrations was observed with a short period of time following sampling if moisture was present within the bulb atmosphere.     

Strong Lithium Polysulfide Chemisorption on Electroactive Sites of Nitrogen‐Doped Carbon Composites For High‐Performance Lithium–Sulfur Battery Cathodes

Despite the high theoretical capacity of lithium–sulfur batteries, their practical applications are severely hindered by a fast capacity decay, stemming from the dissolution and diffusion of lithium polysulfides in the electrolyte. A novel functional carbon composite (carbon‐nanotube‐interpenetrated mesoporous nitrogen‐doped carbon spheres, MNCS/CNT), which can strongly adsorb lithium polysulfides, is now reported to act as a sulfur host. The nitrogen functional groups of this composite enable the effective trapping of lithium polysulfides on electroactive sites within the cathode, leading to a much improved electrochemical performance (1200 mAh g^?1 after 200 cycles). The enhancement in adsorption can be attributed to the chemical bonding of lithium ions by nitrogen functional groups in the MNCS/CNT framework. Furthermore, the micrometer‐sized spherical structure of the material yields a high areal capacity (ca. 6 mAh cm^?2) with a high sulfur loading of approximately 5 mg cm^?2, which is ideal for practical applications of the lithium–sulfur batteries.     

FeCl3模板辅助法由质子盐制备氮、硫、铁三掺杂碳纳米片及其催化氧还原反应

作为一种新型能源技术,燃料电池具有能源转化效率高、燃料可再生、运行安全清洁等优点,因而在应对全球持续增长的能源、环境问题方面受到广泛的研究.但是,燃料电池的阴极氧还原反应(ORR)存在动力学缓慢的固有特性,其反应过电位高,需要在催化剂的辅助下才能顺利发生反应并提供足够的电极电势.目前ORR催化性能最优的是铂基催化剂,但其存在着资源稀缺、价格昂贵、循环寿命差等缺陷,这也是制约燃料电池商业化应用的主要因素.因而要想实现燃料电池的大规模应用,寻找新的可替代铂基催化剂、且储量丰富、价格低廉的优秀ORR催化剂成为了研究的热点.近几年来,杂原子掺杂的碳材料以其价格低、催化性能卓越、优异的稳定性和抗甲醇性能等优点,逐渐发展成为最有前景的ORR催化剂.本文以FeCl3为模板和铁源,质子盐对苯二胺(PPS)为碳、氮、硫源,采用简单的一步中和法制备氮、硫、铁三掺杂的二维介孔碳纳米片催化剂(NSFC).TEM和BET结果显示,FeCl3不仅起到了二维模板的作用,同时在热处理过程中与无定形碳发生作用形成了丰富的介孔,大大提高了材料的比表面积和结构开放性,为ORR反应提供了反应场所.XPS结果显示,质子盐中和合成法不仅有效地简化了NSFC的合成步骤,而且能够灵活地控制材料的元素组成,实现了氮和硫的原位掺杂,有效构筑了杂原子掺杂活性位;同时FeCl3也为催化剂材料引入了Fe元素,进而形成催化活性更加优异的Fe-Nx活性位.电化学测试结果表明,通过调整FeCl3和PPS的比例,NSFC-3催化剂材料在结构形貌和表面功能达到了同时最优化,获得了与商业30 wt%Pt/C可比的催化性能,其起始电位和极限电流密度分别达到了–0.03 V和5.05 mA/cm2,同时NSFC-3具有优于商业30 wt%Pt/C的催化选择性、稳定性和抗甲醇性能.这源于稳定的二维纳米片层结构、丰富的表面介孔结构、大的比表面积和活性位点暴露率以及多种催化活性位点的协同催化效应.     

A facile soft-template synthesis of nitrogen doped mesoporous carbons for hydrogen sulfide removal

A series of nitrogen-doped mesoporous carbons (NMCs) were prepared using Pluronic F127 as a structure directing agent, phloroglucinol and formaldehyde as carbon precursor and dicyandiamide as nitrogen source. The obtained nitrogen-doped mesoporous carbons possess high nitrogen content of 6.37–19.28 wt%. Due to the feature of high nitrogen contents, NMCs show superior H₂S adsorption performance with breakthrough sulfur capacity of 0.48 mmol g^?1 at room temperature and ambient pressure. It is revealed that in addition to the nitrogen content, nitrogen configuration and porosity of the carbon materials also influence significantly their sulfur capacity. This work offers a facile strategy for the synthesis of porous carbon materials with excellent performance in the adsorptive removal of H₂S.     

Synthesis and characterization of mononuclear copper(II) and cadmium(II) complexes with di-(2-picolyl)sulfur

The reaction of Cu(ClO₄)₂·6H₂O and Cd(ClO₄)₂ with di-(2-picolyl)sulfur (dps) leads to the formation of mononuclear complexes [Cu(dps)(H₂O)(ClO₄)](ClO₄) (1) and [Cd(dps)₂](ClO₄)₂ (2). The crystal structure of 1 exhibits a distorted square pyramidal geometry, coordinated by one sulfur and two nitrogen atoms from the dps ligand, one water molecule and one perchlorate oxygen atom. For 2, the environment around cadmium atom is in a distorted octahedron with four nitrogen and two sulfur atoms from the dps ligand. Cyclic voltammetric data show that complexes undergo two waves of a one-electron transfer corresponding to M(II)/M(III) and M(II)/M(I) processes. Spectral and electrochemical behaviors of the complexes are also discussed.     

MECHANISM OF THE REACTION OF DIPHENYL N-BROMOSULFILIMINE WITH SULFIDES,PHOSPHINES AND TERTIARY AMINES

Abstract

The mechanism of the reactions of diphenyl N-bromosulfilimine (I) with such nucleophiles as sulfides, phosphines and tertiary amines was investigated. In the presence of water, (I) reacts with sulfides or phosphines to afford the corresponding sulfoxides or the phosphine oxides in moderate yields; however, the reaction with tertiary amine gave only the N-t-aminosulfilimine derivative. The effect of ring size in the reaction with cyclic sulfides suggests that the reaction proceeds via initial bromine transfer from the nitrogen atom to the sulfur atom of the cyclic sulfides followed by S_N2 type substitution of bromide on the sulfur atom of the cyclic sulfide with the sulfilimino group. The phosphine oxide obtained in the reaction of (I) with optically active methyl n-propyl phenyl phosphine was racemized but retained a small portion of the optical activity. In the case of tertiary amines, even 1,4-diazabicyclo-(2,2,2)-octane (DABCO), in which the back side of the nitrogen atom is blocked, reacted smoothly to afford the corresponding ammonium salts, suggesting the reaction to be of S_N2 type on the nitrogen atom of the sulfilimine.     

SOME SULFUR AND NITROGEN SUBSTITUTED XYLOQUINONES

Abstract

This paper reports reactions of dihalogeno-xyloquinone with sulfur and nitrogen nucleophiles, leading to the di-and mono-substituted derivatives, respectively. The mixed nitrogen-sulfur and carbon-nitrogen derivatives were also synthesized. New reactions, oxidation of dimethylthioxyloquinone to yield a mono-sulfinyl derivative and treatment of the latter with thionyl chloride, are described.

Although dihalogeno-xyloquinones are known compounds^{2a, b} their reactions with sulfur and nitrogen nucleophiles have not been reported. These reactions seemed to be of interest in view of potential biological activity of the expected thio-and amino-substituted xyloquinones, in comparison with the naphthoquinone and benzoquinone analogues.³     

Synthesis,characterization, and crystal structure of cobalt(II) complex with 2-oximino-3-thiosemicarbazone-2,3-butanedione

The reaction of cobalt(II) chloride with the tridentate ligand 2-oximino-3-thiosemicarbazone-2,3-butanedione [Hotsb (1)] leads to the formation of the novel six-coordinated complex [Co(otsb)₂]·2H₂O (2). This complex has been synthesized and characterized by X-ray crystallography, spectroscopic and cyclic voltammetric measurements. The ligand Hotsb (1) obtained by the condensation of 2,3-butanedione monoxime and thiosemicarbazide is used for the preparation of complex 2. The Hotsb (1) crystallizes into a monoclinic lattice with space group P2₁/c. The crystal structure of 2 shows a distorted mer-octahedral geometry in which the ligands are coordinated as uninegatively charged tridentate chelating agents via the hydrazine nitrogen atoms, the azomethine nitrogen atoms, and the thiolate sulfur atoms. The cyclic voltammogram of 2 undergoes two irreversible one-electron waves corresponding to Co^II/Co^III and Co^II/Co^I processes.     

Determining the interaction and characterization of asphaltene in alkylbenzene solvents using nuclear-electron double resonance

This study uses ¹H dynamic nuclear polarization (DNP) methods to determine asphaltene aggregates and the interaction between asphaltene extracted from MC800 asphalt and alkylbenzene solvents, as well as elemental analysis for the characterization of asphaltene. The asphaltene sample was characterized using the elemental analysis of carbon (C), hydrogen (H), nitrogen (N), and sulfur (S). The results show that asphaltenes have the highest carbon content. The sulfur and hydrogen contents are nearly the same and nitrogen content is the smallest. The DNP data provided good results for characterizing asphaltene behavior in alkylbenzene solvents.     

Binuclear paddle-wheel platinum(II) and platinum(III) complexes containing 4-methyl-4H-1,2,4-triazole-3-thiol ligand: Synthesis,X-ray studies,and spectroscopic characterization

The complex [Pt₂(μ-mtrzt)₄(mtrzt)₂] (1) was synthesized from the reaction of a mixture of 4-methyl-4H-1,2,4-triazole-3-thiol (Hmtrzt) and ethylenediamine (en) with K₂PtCl₄ in CH₃OH/H₂O (2:1) as solvent. The complex [Pt₂(μ-mtrzt)₄] (2) was synthesized by the same procedure as described for preparation of complex 1 but in the absence of ethylenediamine. Both complexes were characterized by elemental analysis, IR,¹H NMR,¹³C{¹H}NMR, UV-Vis, as well as luminescence spectroscopy and their structures were analyzed by single-crystal X-ray diffraction method. The X-ray structure determinations show that complexes of 1 and 2 have binuclear structures in a paddle-wheel fashion with Pt-Pt distances of 2.6628(7) and 2.7977(16)Å, respectively. In complex 1, each platinum(III) atom has a distorted octahedral coordination geometry with the sulfur atom and the second platinum subunit in axial positions and two nitrogen and two sulfur atoms in equatorial positions. Also, in complex 2, each platinum(II) atom has a distorted square-pyramidal coordination geometry with the second platinum subunit in axial position and two nitrogen and two sulfur atoms in equatorial positions. In addition, intermolecular C?H···N and C?H···S hydrogen bonds in 1 and 2 as well as intermolecular anagostic C?H···Pt and C?H···π interactions in 2 are effective in the stabilization of the crystal packing of these complexes.     

The Chemical Anisotropy of Polythiozyl, (SN)XElectrode Surfaces

Abstract

Studies on the background currents for polythiozyl electrodes in aqueous media have shown that either a predominantly sulfur or a predominantly nitrogen surface can be obtained. This phenomenon is a function of preparation of the (SN)_X and occurs only on the perpendicular surface of the anisotropic single crystals.     

Microcoulometric Determination of Sulfur and Chlorine by Combustion and Nitrogen by Hydrogenolysis

Abstract

The design of an improved open microcombustion tube and experimental conditions for the rapid, accurate and precise determination of sulfur and chlorine by microcoulometry are described. The design and operating conditions for a catalytic hydrogenolysis tube and scrubber tube for acid removal are also presented for the determination of nitrogen. Examples of the application of the above methods for these elements in petroleum and petrochemicals are presented.