Chlorination, effectiveness

Sodium Hydroxide. Before World War 1, nearly all sodium hydroxide [1310-93-2], NaOH, was produced by the reaction of soda ash and lime. The subsequent rapid development of electrolytic production processes, resulting from growing demand for chlorine, effectively shut down the old lime—soda plants except in Eastern Europe, the USSR, India, and China. Recent changes in chlorine consumption have reduced demand, putting pressure on the price and availabiHty of caustic soda (NaOH). Because this trend is expected to continue, there is renewed interest in the lime—soda production process. EMC operates a 50,000 t/yr caustic soda plant that uses this technology at Green River it came onstream in mid-1990. Other U.S. soda ash producers have aimounced plans to constmct similar plants (1,5). 

As to the praise manner in which chlorine effects the destruction of coloring principles, this is a question upon which there is much difference of opinion. It cannot be questioned, however, that tho injurious action of free chlorine on the substance of oils is owing to its "powerful affinity for hydrogen, and that by the abstraction of this element mere at less completely from the oil, entirely new -and probably substitution compounds are produced, which will account for iliq alteration in the color and consistence of the oil.. ... 

Chlorine Effect on Molecular Descriptors for QSAR Analysis... 

Chlorine Effective. Widely used. Variety of possible application points. Inexpensive. Appropriate as both primary and secondary disinfectant. Harmful halogenated byproducts. Potential conflict with corrosion control pH levels, when used as a secondary disinfectant. 

Approximately 0.99 mg of calcium thiosulfate is required to neutralize 1 mg of residual chlorine at pH 7.35. At pH 11,0.45 mg/L of calcium thiosulfate is sufficient to neutralize 1 mg of chlorine residual. On a weight basis, approx 1.30 parts are needed per part of chlorine at pH 6.5. Although calcium thiosulfate is reported to neutralize combined chlorine effectively, the reactions involved are not currently known. Chlorine neutralization produces HCl and H2SO4 that may result in lower pH. It does not scavenge oxygen significantly, and does not produce SO2. 

Effect of Hydrolyzable Chlorine on Activity of Tin Catalysts. The effect of small amounts of hydrolyzable chlorine on the catalytic activity of DBTDL was studied on the model aliphatic system—isocy-anatoethyl methacrylate and n-butanol. The presence of the hydrolyzable chlorine in isocyanate usually decreases the reactivity of isocyanates in the urethane reaction. The results of measurements of the chlorine effect on the change of the rate constant is summarized in Figure 8. It was determined that the very small amounts of the hydrolyzable chlorine, especially in the form of carbamoyl chloride, increased at the beginning the rate constant for the urethane reaction catalyzed by DBTDL and after achieving the maximum at 500 ppm of chlorine the reactivity decreased. This effect was not observed when benzoyl chloride was used in place of carbamoyl chloride. It was assumed that the activation effect of the chlorine was due to the interaction of the carbamoyl chloride with the DBTDL catalyst. In order to understand this effect, the interaction of DBTDL with carbamoyl chloride of hexamethylene diisocyanate (with and without the presence of n-butanol) was studied using the IR technique. Results are summarized in Figure 9. 

Alben K. 1980. Gas chromatographic-mass spectrometric analysis of chlorination effects on commercial coal-tar leachate. Anal Chem 52 1825-1828. 

Bromimtion. The combination of bromine and chlorine effects, under irradiation, bromination at the site where chlorine normally appears in chlori-nations. The reaction is catalyzed by the hydrogen chloride formed. Straight... 

Fig. 6-12, Propylene chlorination effect of reaction temperature on product compositions.

In this study, hair effects were measured by following changes in hair fiber friction. In general, the effect of chlorine was to increase the coefficient of fiber friction and to decrease the differential friction effect in hair. Changes in hair friction were observed even at parts-per-million levels of chlorine. Effects increased with the number of treatments and with decreasing pH from 8 to 2. 

Figure 3.2 Chlorine effects on tenacity of XLA fiber and elastane fiber. Casey et al. (2008)...

Chemical Chlorine Effective inactivation Relatively low cost Carries residual Membrane degradation. THMs.HAAs formation Toxic gas ... 

Jolley, R.L., et al. Determination of chlorination effects on organic constituents in natural and process waters, in Identification and Analysis of Organic Pollutants in Water [Keith (Ed.)], Ann Arbor (1977)... 

Schiitze M and Hald M (1997), Improvement of the oxidation resistance of TiAl alloys by using the chlorine effect , Mater Sd Eng, A239-240, 847-858. 

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