Chlorine oxide analysis

Some reaction is found to occur between 0( D) atoms (produced from the photolysis of ozone at 253.7 nm and 25 C) and COCIF, as indicated by the high value of the quantum yield for ozone removal. However, no products were found (although analysis was not made for CO 2 which could be the major product), unlike the COCl 2 0( D) reaction, in which evidence was obtained for the formation of both CO and chlorine oxides [1038]. The rate constant for the reaction of COCIF with 0( D) atoms was estimated to be 2.8 times the value... 

The electronic absorption spectra of molecular O2F2 and of the radical O2F have been measured in liquid Ar and in other solvents in the region 190—600 nm/° An analysis of the data concerning the nature of the unstable violet and blue compounds that were first reported in 1962 by Streng and Grosse suggests that the colours are due to oxygen fluoride radicals, such as O2F, and not to chlorine oxide fluorides. Thus, it has now been shown that intensely coloured species are formed by O2 salts in liquid HF these species show the same characteristics as the violet and blue compounds . 

Water samples taken for chlorine dioxide analysis must be analyzed immediately after sampling. Most of the methods worked out for free chlorine measurements can be used for chlorine dioxide analysis if other oxidizing agents are not present. 

Chlorine and chlorine dioxide are other oxidizing agents that may be present in drinking water along with iron (III). Their interference can be removed by purging with nitrogen (for chlorine dioxide) or treatment with sodium oxalate (for chlorine) before analysis for iron (III). Nitrite can be decomposed with ammonium chloride in feebly acidic medium. 

Beggs, K.M.H., Summers, R.S., andMcKnight, D.M. (2009). Characterizing chlorine oxidation of dissolved organic matter and disinfection by-product formation with fluorescence spectroscopy and parallel factor analysis, J. Geophys. Res., 114, G04001. 

This is an indirect method of analysis because the chlorine-containing species do not react with the titrant. Instead the total chlorine residual oxidizes l to l3 , and the amount of 13 is determined by the redox titration with Na282 03. 

In the DPD colorimetric method for the free chlorine residual, which is reported as parts per million of CI2, the oxidizing power of free chlorine converts the colorless amine N,N-diethyl-p-phenylenediamine to a colored dye that absorbs strongly over the wavelength range of 440-580 nm. Analysis of a set of calibration standards gave the following results... 

The second form consists of Pt metal but the iridium is present as iridium dioxide. Iridium metal may or may not be present, depending on the baking temperature (14). Titanium dioxide is present in amounts of only a few weight percent. The analysis of these coatings suggests that the platinum metal acts as a binder for the iridium oxide, which in turn acts as the electrocatalyst for chlorine discharge (14). In the case of thermally deposited platinum—iridium metal coatings, these may actually form an intermetallic. Both the electrocatalytic properties and wear rates are expected to differ for these two forms of platinum—iridium-coated anodes. 

Reagents similai to those used in the analysis of chloiine are commonly employed in the quantitation of gaseous and aqueous chloiine dioxide as well as its reaction coproducts chlorine, chlorite, and chlorate. The volatihty of the gas from aqueous solutions as well as its reactivity to light must be considered for accurate analysis. Other interferences that must be taken into account include other oxidizers such as chloramine, hydrogen peroxide, permanganate, and metal impurities such as ferrous and ferric iron. 

In quantitative analysis we are chiefly concerned with reactions which take place in solution, i.e. ionic reactions. We shall therefore limit our discussion of oxidation-reduction to such reactions. The oxidation of iron(II) chloride by chlorine in aqueous solution may be written ... 

Trace amounts of chlorine suppress the total oxidation. This effect was discovered inadvertently when the selectivity of the process in an industrial plant rose spontaneously from one day to the other. Analysis of the catalyst revealed traces of chlorine, originating from a newly commissioned neighboring chlorine plant. Consequently, small amounts of a chlorine-containing compound, such as ethylene dichloride, are nowadays added to the feed. 

The analysis methods are national in scope and address emissions from a wide variety of industrial and community source types. The materials reviewed are of widely disparate natures. They include metals, and bulk and trace hydrocarbons, including chlorinated and oxide derivatives of hydrocarbons. The analyses are intended to be preliminary screening analyses for use in scoping and prioritizing regulatory attention to toxic exposures from the chemicals studied. 

Starting from the Ni mrao-formyloctaethylporphyrin oxime complex, the meso-cyanooctaethylporphyrin N-oxide complex has been synthesized for the first time. The double addition of the nitrile oxide to 2,5-norbornadiene afford a porphyrin dimer, whose structure has been established by X-ray diffraction analysis (485). The 1,3-dipolar cycloaddition reaction of w< .so-tetraarylporphyrins with 2,6-dichlorobenzonitrile oxide yields isoxazoline-fused chlorins and stereoiso-metric bacteriochlorins. The crystal structure of one of bacteriochlorins has been characterized by X-ray diffraction (486, 487). 

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