Determination of Chloride by Molecular Absorption Spectrophotometry in the Gas Phase Following Oxidation

Abstract

In the proposed method, chloride is oxidized to chlorine gas and the transient absorbance signal of the latter is measured using atomic absorption instrumentation. Instead of the flame, a flow-through absorption cell is used. The method is rapid and direct. The detection limit is 14 μg/mL Cl.     

Photocatalytic Oxidation of Aniline in the Gas Phase Using Porous TiO2 Thin Films

The gas-phase photocatalytic oxidation of aniline on a new kind of porous nano-TiO₂ composite films is investigated. The composite film was prepared on glass fiber with the water glass as binders and dilute H₂SO₄ solution as solidifying reagent. The surface characters were observed by scanning electron microscope. The photocatalytic degradation of aniline on the composite films was carried out in a TiO₂/UV system. Some important factors affecting the photodegradation, such as the concentration of TiO₂, the initial concentration of aniline, and the existing water vapor, are also studied. The product of photocatalytic oxidation was detected by Fourier transform-Infrared. The partial intermediate products were absorbed on TiO₂ surface, which resulted in catalyst deactivation. But when it was irradiated under UV illumination or solar irradiation for some time, the catalyst could be reused without loss of catalytic activity. Translated from the Journal of Wuhan University (Natural Science Edition), 2005, 51(2) (in Chinese)     

气体放电对SO_2和SO_3~(2-)氧化的影响

研究气体放电对SO2和亚硫酸盐氧化的影响,采用了直流电源和交直流叠加电源进行气体放电.结果表明,气体放电对于SO2氧化促进作用很少;但对溶液中的SO2-3的氧化则有明显促进作用.通过对两个反应过程的机理分析,认为亚硫酸盐溶液氧化快是因为气体放电产生的OH等自由基和液相里的亚硫酸根起作用,引发链反应,促进了溶液中四价硫被空气中的O2氧化为六价硫的过程.而气相中的SO2与OH等自由基作用不能形成链反应,所以影响不明显.实验表明,选择交直流叠加电源进行气体放电比用纯粹直流电源放电效果更好.     

Benzene Oxidation by ‘Bare’ FeO+ in the Gas Phase

Bare FeO⁺ reacts in the gas phase with benzene at collision rate (k = 1.3 × 10^?9 cm³ molecule^?1 s^?1), giving rise to the formation of Fe(C₆H₄)⁺/H₂O(5%), Fe(C₅H₆)⁺/CO(37%), Fe(C₅H₅)⁺/CO/H. (2%), and Fe⁺/C₆H₅OH (56%). Neither the reaction rate nor the product distribution are subject to a significant kinetic isotope effect, thus, ruling out several mechanistic variants described in the literature to the operative for ‘analogous’ arene oxidation processes in solution. A mechanism is suggested which is in keeping with the experimental findings, and which also accounts for some remarkable results obtained, when two [Fe, C₆,H₆H₆O]⁺ isomers are generated and subjected to a neutralization-re-ionization experiment in the gas phase.     

A Proposed Mechanism of Photocatalytic Oxidation of Trichloroethylene in Gas Phase

Heterogeneous photocatalytic oxidation (PCO) using TiO, is attracting more and moreresearch groups with great promise as a simple and inexpensive method to mineralizevolatile organic compounds (VOCs)'. There has been a great deal of interest in thephotocatalytic oxidation of TCE due to its role as a significant environmentalcontain inant2-6.In the ideal PCO reaction, TCE is completely mineralized into CO, and HCIby, TiO'C,C13 3/2O= H,O ~ ZCOZ 3 HCI fUnfortunately the comple…     

气相中Y^＋活化CS2中的C—S键

以Y+与CS2反应作为第二行前过渡金属离子与CS2反应的范例体系.采用密度泛函UB3LYP方法,对于Y+采用Stuttgart赝势基组,对于CS2采用6-311+G(2d)基组,计算研究了Y+离子在基态和激发态时与CS2气相反应的机理.并用UCCSD(T)方法在相同的基组水平上对各驻点作了单点能量校正.结果表明Y+离子与CS2的反应是插入-消去反应,在反应过程中会发生系间窜越,并且找到了两个势能面的能量最低交义点.     

Synthesis of Sulfoxides by Phase Transfer Catalyzed Oxidation of Sulfides by Cerium(IV) Ammonium Nitrate

Diaryl, dialkyl and alkyl aryl sulfides are oxidized by cerium (IV) ammonium nitrate in H₂ O/CH ₂ Cl ₂, in the presence of tetra-n-butylammonium bromide, at room temperature, to give sulfoxides in yields ranging between 90 and 100%.     

单硫代和双硫代甘油醚在直链淀粉-三（3,5-二甲基苯基氨基甲酸酯）固定相上的手性拆分

合成了直链淀粉三(3,5二甲基苯基氨基甲酸酯)手性固定相。用该固定相对6种单硫代甘油醚和4种双硫代甘油醚进行了手性拆分。单硫代甘油醚对映异构体得到了较好的分离,而双硫代甘油醚完全不能拆分。提出了样品与固定相的作用模式。     

Chlorine-radical Induced Oxidation of Glyoxal and Glyoxal-S（IV） Adducts in the Aqueous Phase

A laser flash photolysis study of the reactivity of Clwith glyoxal, glyoxal mono- and dibisulfite adducts, 1-hydroxy-2, 2-diol-ethanesulfonate and 1, 2-dihydroxy-1, 2-ethanedi sulfonate in the aqueous phase was carried out. The obtained rate constants can be used for atmospheric modeling.     

模拟唾液浸泡塑料玩具溶出的邻苯二甲酸二(乙基己基)酯的固相微萃取-气相色谱法测定

利用新型溶胶 -凝胶富勒烯C60 涂渍的萃取头 ,采用顶空固相微萃取 -气相色谱法 ,研究了用模拟唾液浸泡塑料玩具溶出的邻苯二甲酸二(乙基己基)酯(DEHP)的固相微萃取(SPME)条件 ,并对聚氯乙烯玩具制品的模拟唾液浸泡液中增塑剂进行了分析和测定 ,方法的检出限为1.02μg/L ,实际样品的检出限为10.2×10-6(w) ,相对标准偏差RSD=10.5 %(n=7)。     

CO2 Activation by Zr+ and ZrO+ in Gas Phase

The gas-phase reduction of carbon dioxide to carbon monoxide, induced by Zr⁺ and ZrO⁺ catalysts, was investigated at density functional level of theory. Calculations were carried out using both hybrid and pure exchange-correlation functionals in order to reproduce adequately the energetic gap between the Zr^{+ 4}F and ²D electronic states and experimental reaction heats. In agreement with a guided ion beam tandem mass spectrometer study, we have found that carbon dioxide activation by Zr⁺ presents a spin-forbidden mechanism because of a spin inversion process occurring during reaction in the rate- determining step. ZrO⁺ interacts with CO₂ through two possible pathways both endothermic: formation of ZrO ₂ ⁺ and CO products is less unfavourable. Information about ground and excited states of ZrO⁺ and ZrO ₂ ⁺ oxides and bond dissociation energies of species present on the reaction paths was also given.     

Die Bestimmung von Propan-1,3-diol (Trimethylenglykol) in Glycerin

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