Cl+F2→ClF+F和F+ClF′→ClF+F′反应机理的密度泛函理论研究

用密度泛函理论(DFT)B3LYP方法, 在6-311G基组下,计算研究了反应Cl+F2→ClF+F和对称反应F+ClF′→ClF+F′的机理。求得前者的过渡态为三角形,活化能为15.57 kJ*mol-1;后者的过渡态为线形和三角形,活化能分别为11.52和196.25 kJ*mol-1。结果均经过振动分析和IRC计算验证。     

An AB Initio Correlated Computation of Vibrations in the CIONO2 Molecule

Abstract

ClONO₂ is treated ab initio by the second order M?ller-Plesset perturbation approach with the 6-31G? basis set. The minimum-energy structure is planar (C_s symmetry) while in the activated complex for internal rotation around the NO bond the Cl atom exhibits torsion by 90° but the structure has the C_s symmetry, too. For both structures harmonic vibrational frequencies and IR intensities are calculated. The agreement with available observed data from matrix isolation is very good. The MP₂ frequencies are mostly somewhat lower comparing to related SCF values. The energetics is also evaluated in the MP4 fourth order perturbation treatment. The best value found for the barrier of internal rotation is 31 kJ/mol, i.e. significantly low.     

A Computational Study of CIONO2H+: Structure and Vibrations

Two protonated forms of chlorine nitrate, HClONO⁺ ₂ and ClONO₂H⁺, are treated ab initio by the Hartree-Fock and the second order Møller-Plesset perturbation approach with the standard 6–31G* basis set. Both minimum energy structures are planar (C ₃ symmetry) and their structural, energy, and vibrational parameters are reported. The computations conclude that the proton attacks the chlorine nitrate at its central, not end, oxygen atom. The protonation causes a considerable elongation of the central ON bond which becomes most probable place of cleavage. The dissociation should yield the neutral HOCl and NO⁺ ₂. These quantum-chemical findings well agree with the previous experimental indications.

     

三氧消毒杀菌与紫外线消毒杀菌效果的研究

对三氧消毒杀菌与紫外线对空气杀菌消毒的效果进行了比较，选择供应室无菌间的两间面积相同的房间，使用三氧消毒机和紫外线灯，照射到各自规定的时间进行空气采样，暴露15min后，置37℃培养24h，观察结果并进行菌落计数。结果表明，三氧消毒杀菌机的消毒作用优于紫外线灯，其消毒杀菌的安全性高，杀菌效果明确，是空气消毒理想的一种新型消毒方法。     

Gas-diffusion flow injection assay for the selective determination of chlorine dioxide based on the fluorescence quenching of chromotropic acid

The present work reports the first spectrofluorimetric gas-diffusion flow injection (GD-FI) assay for the determination of chlorine dioxide in water samples (tap, mineral and soda water). The method is based on the fluorescence quenching of chromotropic acid (CA) (λ_ex. = 347 nm, λ_em. = 371 nm) caused by the analyte. The chemical and instrumental variables of the system were studied in terms of maximum sensitivity. The gas-diffusion cell was thermostated at 40 °C to enhance the vaporization of chlorine dioxide and thus the sensitivity of the method. The quenching effect of chlorine dioxide on CA was linear in the range 0.09-3.41 mg l^− 1, while the precisions either close to the quantitation limit or near to the middle of the linear section of the calibration graph were satisfactory in both cases (s_r = 2.6% and 1.5% (n = 10) at 0.17 and 1.71 mg l^− 1 level, respectively). The developed method proved to be adequately selective and sensitive with 3σ limit of detection equal to c_L = 0.03 mg l^− 1. The application of the assay to spiked tap, mineral and soda water samples yielded accurate results with recovery values in the range 94.1-105.9%.     

Determination of Chlorine Dioxide Using Capillary On-Line Concentration Coupled with Flow Injection Analysis

A new method for the determination of chlorine dioxide (ClO₂) using capillary (Teflon filter tube) on-line concentration coupled with a flow injection system is proposed. The method is based on the color reaction of 4-aminoantipyrine (4-AAP) with phenol in the presence of ClO₂. The colored product is proportional to the concentration of ClO₂ and can be efficiently concentrated in the Teflon filter tube, following elution and spectrophotometric detection in a flow-through cell. The sensitivity of the method increases about 100 times after concentration. As a result, one of the most sensitive methods of determining ClO₂ (ppb) is obtained. The linear range after concentration is 5–250µg·L^–1 ClO₂. The detection limit is 0.5µg·L^–1. The interferences from other chlorinated compounds and metal ions were eliminated by utilizing gas-phase separation via porous polytetrafluoroethylene (PTFE) membrane for pretreatment.     

硝酸氯在冰表面上反应的研究

对硝酸氯与一，二，三个水分子的反应作为硝酸氯在冰表面上反应的模型进行了理论研究．MP2     

Reaction with N,N‐Diethyl‐p‐phenylenediamine: A Procedure for the Sensitive Square‐Wave Voltammetric Detection of Chlorine

The reaction of chlorine and N,N‐diethyl‐p‐phenylenediamine has been studied as a means of generating an analytical voltammetric signal of much improved sensitivity and selectivity for the detection of the former than is possible via direct electrolysis. A reaction mechanism is suggested whereby the chlorine attacks the primary amine of DEPD to form the N‐chlorinated product that shows a much enhanced signal under conditions of square‐wave voltammetry than does chlorine itself. The analytical parameters were found to vary with concentration of DEPD and a linear range from 17 to 495 μM was achievable with a corresponding limit of detection of 6.8 μM     

Optosensing of chlorine gas using a dry reagent strip and diffuse reflectance spectrophotometry

Chlorine gas concentrations in the range 0–5 ppm can be measured with a limit of detection of 0.043 ppm using an immobilized reagent (o-tolidine is best) and refiectance spectrophotometry. The system described utilizes a nylon tape dry reagent carrier whose change in reflectance over 10 s is probed in real time by means of an optical fibre.     

Weak Interionic Interactions in 2‐Haloimidazolium Hexahalotellurates(IV) [1]

The 2‐haloimidazolium salts [C₁₁H₂₀N₂X]X [ 1 ; X = Cl ( a ), Br ( b )] react with TeX₄ to give the salts [C₁₁H₂₀N₂X]₂[TeX₆] [ 2 ; X = Cl ( a ), Br ( b )]. The crystal structure analyses of 2a and 2b · CH₂Cl₂ reveal the presence of ionic pairs linked by weak halogen to halogen interactions.