Photoemission studies of rhenium disulfide oxidation: Altered core-level structure and reactivity of defect sites

X-ray photoemission was used to investigate the initial stages of rhenium disulfide oxidation and the altered reactivity and core-level electronic structure of defect sites produced by argon ion sputtering of single crystal and polycrystalline ReS₂-basal plane surfaces. Oxidation of polycrystalline-ReS₂ with O₂ at 100–300 ° C produced a mixture of surface oxides containing rhenium in the + 4 and + 7 oxidation states. Oxidation was facilitated by the presence of low coordination defect sites and was reversible upon resulfidization with H₂S/H₂ at 300 °C.     

Optimization of oxidative desulfurization of thiophene using Cu/titanium silicate-1 by box-behnken design

The oxidative desulfurization of thiophene in a synthetic mixture of thiophene and iso-octane was investigated with copper loaded titanium silicate-1 (TS-1) catalyst in presence of hydrogen peroxide as oxidising agent and the conversion was enhanced by 22% at 240 min on addition of 1.05 wt.% copper in TS-1. The optimal design of experiments using box-behnken method was employed to evaluate the effects of individual process variables such as, reaction temperature, amount of catalyst and moles of hydrogen peroxide per mole of thiophene and their optimum values were found to be 70 °C, 0.45 g (22.5 mol/L of iso-octane) and 19.9 mol (in 20 ml of iso-octane), respectively, to achieve a conversion of 93%. The influence of mass transfer effects on the desulfurization reaction was minimized by selecting proper degree of agitation and catalyst size. An empirical kinetic model was used to interpret the rate data. The apparent activation energy was found to be 28.67 kJ/mol.     

Monte Carlo simulations of phase behavior and microscopic structure for supercritical CO2 and thiophene mixtures

The phase equilibria of thiophene in supercritical carbon dioxide are calculated by Monte Carlo simulations in Gibbs ensemble using a united atom force field. To validate the simulations, binary vapor–liquid coexistence curves were computed for two different temperatures using Monte Carlo simulations. An excellent agreement between simulations and experimental data is obtained. The effects of pressure on structural properties were studied for thiophene–CO₂ binary mixtures. The radial distribution functions and local composition of thiophene in CO₂ were investigated over a range of pressures. A weak dependence of thiophene structural properties with pressure was observed in supercritical phase. Local solution structure of thiophene in supercritical CO₂ was studied by computing angular–radial distribution functions and spatial distribution functions with three-dimensional probability distributions. The characteristic angular–radial distributions show a mutually parallel arrangement between thiophene plane and CO₂ molecules within the first solvation shell. Spatial distribution functions (SDFs) results show that CO₂ molecules have two higher probability distributions around thiophene molecules located above and below the thiophene ring.     

介孔碳片的合成及吸附脱硫性能

采用溶胶-凝胶法,以三嵌段共聚物聚氧化乙烯氧化丙烯氧化乙烯EO27- PO61-EO27 (P104)为模板剂,蔗糖为共模板,正硅酸乙酯(TEOS)为硅源,在强酸性及无机盐存在条件下制备出介孔硅片,并以此为硬模板,通过浓硫酸处理的方法成功制备了介孔碳片.并采用扫描电子显微镜、N2吸附-脱附实验对合成的介孔碳片进行了表征...     

双三氟甲基磺酰亚胺离子液体萃取氧化脱硫

分别以N-甲基咪唑和吡啶为阳离子,合成了10种通式为CnMimNTf2(n=2,3,4,5,6)和CnPyNTf2(n=2,3,4,5,6)的双三氟甲基磺酰亚胺类离子液体;并以离子液体为萃取剂,以质量分数35％的H2 O2为氧化剂,考察了各离子液体与H2 O2组成的氧化体系对模拟油品中含硫化合物噻吩的氧化萃取能力,比较...     

Copolymer from electropolymerization of thiophene and 3,4-ethylenedioxythiophene and its use as cathode for lithium ion battery

Electropolymerizations (EPs) of thiophene (Th), 3,4-ethylenedioxythiophene (EDOT) and the mixed monomers of Th and EDOT in 0.05 M Et₄NClO₄/propylene carbonate (PC) solution were performed to prepare polymer films as potential cathode materials in lithium ion battery. The incorporation of EDOT units into pure polythiophene (PTh) chain leads to large alternations on the experimental conditions of EPs and the properties of the resulting polymer films. Onset potential of the EPs was reduced with the participation of EDOT component. The resulting polymers, PTh, poly(3,4-ethylenedioxythiophene) (PEDOT) and poly(thiophene-co-3,4-ethylenedioxythiophene) (PTh-EDOT) were then served as cathode materials to test their capabilities to transport lithium ion in 1.0 M LiPF₆/ethylene carbonate/dimethyl carbonate solution. With the inherent EDOT unit, PEDOT and PTh-EDOT have better charge capacity, stability and response rate than pure PTh. Among the copolymers, PTh-EDOT (1/1) even shows better stability than pure PEDOT homopolymer, advantage of using EDOT as copolymer component is thus evaluated.     

The influence of the monomer and the ionic liquid on the electrochemical preparation of polythiophene

Thiophene, bithiophene and terthiophene have been electropolymerised using ionic liquids as the growth medium and the supporting electrolyte. Both imidazolium and pyrrolidinium-based ionic liquids were used to assess the influence of the nature of the ionic liquid on the morphology and electrochemical activity of the conducting polymers. The pyrrolidinium-based ionic liquid produced slightly smoother films for all the thiophene species studied. A number of the polymers displayed multiple redox peaks, the possible origins of which are discussed. Both the ionic liquid and the choice of monomer had a significant influence on the polymer produced.     

噻吩生产及市场应用

本总结了噻吩生产及应用情况．介绍了各种噻吩衍生物的制备方法及用途，对国内噻吩市场做了初步分析，并对噻吩行业的发展提出了建议。     

Synthesis and optical properties of novel, thermally stable phenanthrolines bearing an arylthienyl-imidazo conjugation pathway

Six new hyperpolarizable chromophores based on functionalized arylthiophene donors and an imidazo-phenanthroline acceptor moiety have been designed and synthesized for the first time in good to excellent yields by condensation of 5,6-phenantroline-dione with formyl-arylthiophene derivatives in the presence of ammonium acetate in glacial acetic acid. The thermal stability, solvatochromic and nonlinear optical properties of these compounds were evaluated.     

Visible light photocatalytic degradation of thiophene using Ag–TiO2/multi-walled carbon nanotubes nanocomposite

Ag–TiO₂ nanocatalyst, supported on multi-walled carbon nanotubes, was synthesized successfully via a modified sol–gel method, and the prepared photocatalyst was used to remediate aqueous thiophene environmentally by photocatalytic oxidation under visible light. The prepared Ag–TiO₂/multi-walled carbon nanotubes nanocomposite photocatalyst was characterized through X-ray diffraction, Brunauer–Emmett–Teller (BET), transmission electron microscopy, and UV–vis spectra (UV–vis). The results showed that both Ag and TiO₂ nanoparticles were well-dispersed over the MWCNTs and formed a uniform nanocomposite. Ag doping can eliminate the recombination of electron–hole pairs in the catalyst, and the presence of MWCNTs in the TiO₂ composite can change surface properties to achieve sensitivity to visible light. The optimum mass ratio of MWCNT:TiO₂:Ag was 0.02:1.0:0.05, which resulted in the photocatalyst's experimental performance in oxidizing about 100% of the thiophene in a 600 mg/L solution within 30 min and with 1.4 g L⁻¹ amount of catalyst used.