The Chlorites

The chlorite crystal is made up of alternate layers of talc and brucite, as above. Naturally-occurring chlorites may differ somewhat from the above formula, because further substitutions may occur e.g. a further Al may replace Si, or Fe may replace Mg or Al. 

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The reaction involving chlorite and iodide ions in the presence of malonic acid, the CIMA reaction, is another that supports oscillatory behaviour in a batch system (the chlorite-iodide reaction being a classic clock system the CIMA system also shows reaction-diffusion wave behaviour similar to the BZ reaction, see section A3.14.4). The initial reactants, chlorite and iodide are rapidly consumed, producing CIO2 and I2 which subsequently play the role of reactants . If the system is assembled from these species initially, we have the CDIMA reaction. The chemistry of this oscillator is driven by the following overall processes, with the empirical rate laws as given ... 

Consequently, when D /Dj exceeds the critical value, close to the bifurcation one expects to see the appearance of chemical patterns with characteristic lengtli i= In / k. Beyond the bifurcation point a band of wave numbers is unstable and the nature of the pattern selected (spots, stripes, etc.) depends on the nonlinearity and requires a more detailed analysis. Chemical Turing patterns were observed in the chlorite-iodide-malonic acid (CIMA) system in a gel reactor [M, 59 and 60]. Figure C3.6.12(a) shows an experimental CIMA Turing spot pattern [59]. 

Organic Reactions. The chlorite ion, CIO,, is mosdy a weak and slow oxidizer in alkaline aqueous solutions. Aldehydes (qv) can be readily oxidized to the corresponding carboxyhc acids in neutral or weakly acidic solutions. Mixing sohd sodium chlorite with combustible organic materials can result in explosions and fire on shock, exposure to heat, or dames. 

Sodium chlorite is not Hsted by the USEPA or any regulatory authority as a carcinogen. Studies conducted ia mice and rats did not show an increase in tumors in animals exposed to sodium chlorite in thek drinking water. Sodium chlorite has been found to have mutagenic activity in some in vitro test systems such as the Ames Salmonella reverse mutation assay without the presence of metaboHc activators. The significance of these test results in regard to human health is not clear because of the oxidizing effects of the chlorite ion (149). 

In many patent orHterature descriptions, a stabilized chlorine dioxide solution or component is used or described. These stabilized chlorine dioxide solutions are in actuaHty a near neutral pH solution of sodium chlorite that may contain buffer salts or additives to obtain chlorite stabiHty in the pH 6—10 range. The uv spectra of these solutions is identical to that of sodium chlorite. These pH adjusted chlorite solutions can produce the active chlorine dioxide disinfectant from a number of possible organic or inorganic chemical and microbiological reactions that react, acidify, or catalyze the chlorite ion. 

R. M. Harrington, D. Gates, and R. R. Romano, "A Review of the Uses, Chemistry and Health Effects of Chlorine Dioxide and the Chlorite Ion, Chlorine Dioxide Panel of the Chemical Manufacturers Association, Washington, D.C., Api. 1989. 

A major disadvantage of this system is the limitation of the single-pass gas-chlorination phase. Unless increased pressure is used, this equipment is unable to achieve higher concentrations of chlorine as an aid to a more complete and controllable reaction with the chlorite ion. The French have developed a variation of this process using a multiple-pass enrichment loop on the chlorinator to achieve a much higher concentration of chlorine and thereby quickly attain the optimum pH for maximum conversion to chlorine dioxide. By using a multiple-pass recirculation system, the chlorine solution concentrates to a level of 5-6 g/1. At this concentration, the pH of the solution reduces to 3.0 and thereby provides the low pH level necessary for efficient chlorine dioxide production. A single pass results in a chlorine concentration in water of about 1 g/1, which produces a pH of 4 to 5. If sodium chlorite solution is added at this pH, only about 60 percent yield of chlorine dioxide is achieved. The remainder is unreacted chlorine (in solution) and... 

As the result of a mix-up at a distribution center, two tank track drivers received each other s papers. One of the trucks carried a load of sodium chlorite solution, and the other carried epichlorohydrin. The chlorite truck went to the customer who was expecting epichlorohydrin and was off-loaded into a tank that already contained some epichlorohydrin. The result was an explosion and a serious fire fumes and smoke led to the closure of the bridges over the Severn Estuary. UK [12, 13]. 

The C102 ion is nonlinear, as expected, and X-ray studies of NH4CIO2 (at —35°) and of AgC102 lead to the dimensions Cl-O 156 pm, angle O-Cl-O 11 r. The chlorites of the alkali metals and alkaline earth metals are colourless or pale yellow. Heavy metal chlorites tend to explode or detonate when heated or struck (e.g. those of Ag+, Hg+, T1+, Pb + and also those of Cu + and NH4+). Sodium chlorite is the only one to... 

Write the 1 ewis structures of (a) water, H20 (b) methanal, H2CO and (c) the chlorite ion, CI02. Use the rules in Toolbox 2.1 note that we must add one electron for the negative charge of C102. ... 

The chlorite dismutase that generates oxygen from chlorite produced by reduction of chlorate has been purihed and characterized from strain GR-1 (Van Ginkel et al. 1996) and from Ideonella dechloratans (Stenklo et al. 2001). The enzyme from Dechloromonas agitata has been suggested as a metabolic probe for chlorate reduction in the environment (Bender et al. 2002). 

Bender KS, SM O Connor, R Chakraborty, JD Voates, LA Achenbach (2002) Sequencing and transcriptional analysis of the chlorite dismutase gene of Dechloromonas agitata and its use as a metabolic probe. A/ / / Environ Microbiol 68 4820-4826. 

Sheet silicates (Q ) with significant isomorphic replacement of Si by AF+ or Fe +. These were decomposed by poly(acrylic add) to silica gel. The chlorite, thuringite, formed a strong cement but was much affected by water. 

Chlorite is abundant in Cu-Pb-Zn-rich deposits but is scarce in Au-Ag-rich deposits. Fe chlorite is the most common and Fe-Mg chlorite is subordinate (Shirozu, 1969). Almost all of the chlorite is classified as orthochlorite which can be regarded as part of the clinochlore-daphnite solid solution series. In general, chlorite is intimately associated with sulfide minerals such as sphalerite, galena, pyrite, chalcopyrite, and pyrrhotite. A 7 A septechlorite was reported from the Toyoha Pb-Zn deposits (Sawai, 1980). Interstratified chlorite-smectite and vermiculite-saponite are rather common minerals in Au-Ag deposits (e.g., Yoneda and Watanabe, 1981), but they have not yet been reported from other deposits. 

The redox condition of the deep fluids may be buffered by the chlorite-pyrite equilibrium. 

The concentration of chlorine dioxide, chlorite and total oxidants was determined on site using a portable colorimeter (Palintest Photometer 5000) and a modification of the DPD test in which any chlorine species are complexed with glycine to ensure only chlorine dioxide reacts with DPD. The chlorite and total oxidants are then determined on a fresh sample by acidification and neutralisation in the presence of potassium iodide. The initial dose level was set at 0.3ppm chlorine dioxide injected in the water feed to the cold... 

Red phosphorus and the chlorite react very exothermally in aqueous suspension above 50°C, and there may be a sudden and near-explosive stage in the redox reaction after an induction period. 

Sodium chlorite reacts very violently with organic compounds of divalent sulfur, or with free sulfur (which may ignite), even in presence of water. Contact of the chlorite with rubber vulcanised with sulfur or a divalent sulfur compound should therefore be avoided [1]. Application of factorial design techniques to experimental planning gave specific conditions for the safe oxidation of organic sulfides to sulfoxides using sodium chlorite or calcium hypochlorite [2],... 

Carbon, red phosphorus, or sulfur are oxidised violently by the chlorite. 

The chloritic tourmaline ore type contains significant quantities of ferrosilicates, tourmaline and chlorites. 

Fox, R. O., G. Erjaee, and Q. Zou (1994). Bifurcation and stability analysis of micromixing effects in the chlorite-iodide reaction. Chemical Engineering Science 49, 3465-3484. 

Chlorine dioxide can be formed out of the chlorite by either of the reactions described by Equation 25.3 or 25.8. Equation 25.1 describes the chlorite formation. The chlorine concentration in the liquid is normally very low as the reaction with caustic (Equation 25.4) is very fast. The concentration of chlorine and/or hypo-chlorous acid HOCl can increase on depletion of hydroxide ions in the liquid. As in step two of the hypochlorite unit, the caustic concentration is in the order of 4-10 g l-1 and it is possible to conclude that at the gas-liquid interface the concentration might be quite low owing to the fast reaction with chlorine. 

When there is a peak flow of chlorine in the feed-stream the redox potential decreases and the amount of caustic that is dosed increases automatically. Caustic is fed to the jet-loop and its flow is regulated by the measurement of the redox potential. When the lead time is long there is a shortage of caustic, which results in a lower level of free caustic that leads to a higher chlorine concentration. This chlorine subsequently reacts with the chlorite in the hypochlorite solution to form chlorine dioxide. The absorption of chlorine dioxide by the caustic is then very limited in step one and is hardly absorbed at all in the caustic present in step two of the production and is emitted with the inert gas stream. 

Silicate minerals that usually occur as spherulitic aggregates of fibers have formed as a result of the alteration of the many minerals subsumed within the category of biopyriboles. Alteration of the micas under hydrothermal conditions produces compositional variants on recrystallization such as hydrous muscovite. Some of these samples have been labeled asbestiform, probably because they are found in veins that criss-cross rock masses. Fibrous micaceous minerals also occur as discrete disseminated particles, although few detailed analyses of crystallites from the disperse occurrences have been made. Fibrous mica found in veins usually grades (composition-ally) into members of the serpentine mineral group, the clays or the chlorites. 

The chlorites are a group of sheet silicate minerals similar to the micas and talc. The general formula, A5 6T40io(OH) j, is deceptively simple. The range of possible substitutions is enormous, for example, A = Mg, Al, Fe, ... 

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