Chlorine, gaseous

Disinfeetion. Chlorine, as gaseous chlorine or as the h5rpochlorite ion, is widely used as a disinfectant. However, its use in some cases can lead to the formation of toxic organic chlorides, and the discharge of excess chlorine can be harmful. Ozone as an alternative disinfectant leads to products that have a lower toxic potential. Treatment is enhanced by ultraviolet light. Indeed, disinfection can be achieved by ultravifflet light on its own. 

The presence of chloric(I) acid makes the properties of chlorine water different from those of gaseous chlorine, just as aqueous sulphur dioxide is very different from the gas. Chloric(I) acid is a strong oxidising agent, and in acid solution will even oxidise sulphur to sulphuric acid however, the concentration of free chloric(I) acid in chlorine water is often low and oxidation reactions are not always complete. Nevertheless when chlorine bleaches moist litmus, it is the chloric(I) acid which is formed that produces the bleaching. The reaction of chlorine gas with aqueous bromide or iodide ions which causes displacement of bromine or iodine (see below) may also involve the reaction... 

The smell of chlorine water, somewhat different from that of gaseous chlorine, may be due to minute amounts of evolved dichlorine monoxide ... 

Acetic acid can be chlorinated by gaseous chlorine in the presence of red phosphorus as catalyst to yield successively mono-, di-, and tri-chloroacetic acid the reaction proceeds better in bright sunlight. If the chlorination is stopped when approximately one molecule of chlorine per molecule of acetic acid is absorbed the main product is monochloroacetic acid ... 

Note 2. Introduction of gaseous chlorine may lead to an explosion, owing to reaction with the diethyl ether. 

Chlorine is produced as a gas that is used captively, transferred to customers via pipeline, or Hquefied. Liquid chlorine, of higher purity than gaseous chlorine, is either used internally by the producers or marketed. The percentage of U.S. chlorine gas production subsequently Hquefied has increased over the past ten years reflecting higher demand for high purity chlorine. This percentage was 60.7% in 1978 and 81.1% in 1987 (5). The majority of this chlorine is consumed captively. 

Fig. 31. Density of gaseous chlorine as a function of temperature at various pressures. To convert kPa to psig, multiply by 0.145 and subtract 14.6. (77).

Chlorine Monofluoride. Chlorine monofluoride is a colorless gas that condenses to a Hquid with a slight yeUow cast and free2es to a white soHd. The infrared spectmm of gaseous chlorine monofluoride and the Raman spectmm of the Hquid have been studied (36). The uv-absorption spectmm (37) and vapor pressure data are also available (11). 

A proposed method which avoids cyanide consists of treating gold ore with gaseous chlorine at elevated (<250° C) temperatures to volatilise gold as chloride Au2Clg [12446-79-6] or AuMCl, (M = Fe [12523-43-2] A1 [73334-09-5], or Ga [73334-08-4]) and recovering it by condensation (23). 

The clarified and acidified brine is treated with gaseous chlorine which is injected into the solution in a small excess over the theoretical stoichometric relation by weight of 0.28 1 chlorine to iodide. The oxidation occurs according to... 

Part of the continuously recirculated solution is bled off and sent to the iodine finishing process. Iodine finishing consists of contacting this bleed of concentrated acidic iodide solution with gaseous chlorine, through which iodine is formed by oxidation and precipitated. After iodine precipitation, the resulting acidic mother Hquor, saturated with free iodine, is pumped back to acidify the clarified brine and to recover the remaining iodine. 

Opa.nte. There are two methods used at various plants in Russia for loparite concentrate processing (12). The chlorination technique is carried out using gaseous chlorine at 800°C in the presence of carbon. The volatile chlorides are then separated from the calcium—sodium—rare-earth fused chloride, and the resultant cake dissolved in water. Alternatively, sulfuric acid digestion may be carried out using 85% sulfuric acid at 150—200°C in the presence of ammonium sulfate. The ensuing product is leached with water, while the double sulfates of the rare earths remain in the residue. The titanium, tantalum, and niobium sulfates transfer into the solution. The residue is converted to rare-earth carbonate, and then dissolved into nitric acid. 

Two oxidants commonly used are chlorine and potassium permanganate. The Roe chlorine number, the uptake of gaseous chlorine by a known weight of unbleached pulp (ie. Technical Association of the Pulp and Paper Industry (TAPPl) Standard Method T202 ts-66) has been superseded by the simpler hypo number (ie, TAPPl Official Test Method T253 om-86), eg, chlorine consumption in treatment of the pulp with acidified sodium or calcium hypochlorite. 

Fabric preparation is often considered to be the most important stage to obtain good color yields, levelness, and brightness on wool fabric (104). This is done almost exclusively by an oxidative chlorination process, the most popular commercial methods using either a batch treatment with dichloroisocyanuric acid (DCCA), or a continuous fabric treatment with gaseous chlorine, called the Kroy process. 

Hypochlorites. A common dry form of chlorine used as a bleach or water purifier is made by reaction of gaseous chlorine and high calcium hydrated lime ... 

Anhydrous hypochlorites ate oxidi2ed to chlorates by CI2O (176). The rate of chlorate formation decreases in the order Na > Ba > Si > Li > Ca. In the presence of gaseous chlorine, dry hypochlorites decompose in two ways ... 

Commercial chlorohydrin reactors are usually towers provided with a chlorine distributor plate at the bottom, an olefin distributor plate about half way up, a recirculation pipe to allow the chlorohydrin solution to be recycled from the top to the bottom of the tower, a water feed iato the recirculation pipe, an overflow pipe for the product solution, and an effluent gas takeoff (46). The propylene and chlorine feeds are controlled so that no free gaseous chlorine remains at the poiat where the propylene enters the tower. The gas lift effect of the feeds provides the energy for the recirculation of the reaction solution from the top of the tower. 

Environment Internal Entering water temperature 85°F (29 C), exiting water temperature 115°F (46°C), pressure -120 psig (0.82 MPa), pH 7.5-7.6, gaseous chlorination 0.3-0.6 ppm free with spike of 3 ppm weekly 14-16 ppm orthophosphate 3.0-3.5 ppm zinc dispersant. External Cracked gasoline, 130 psi (0.9 MPa)... 

C. W. Scheele prepared and studied gaseous chlorine (Mn02 -f- HCl) but thought it was a compound 1785 Chemical bleaching (eau de Javel aqueous KOH 4-CI2) introduced by C.-L. Berthollet... 

Some crevice attack upon titanium can also occur in the presence of gaseous chlorine gas at temperatures below 100°C, but this is mainly confined to crevices formed between titanium and organic sealing compounds. Here again, the Ti-0- 15Pd alloy is less prone to attack. 

Other media in which titanium is subject to pyrophoricity are anhydrous liquid or gaseous chlorine , liquid bromine, hot gaseous fluorine, or oxygen-enriched atmospheres at moderately low pressures. 

The bulbs contain tleft to right) gaseous chlorine and the vapors in equilibrium with liquid bromine and solid iodine. 

Anode processes yield gaseous chlorine, fluorine, carbon chloride or fluoride. In the case of melts containing dissolved tantalum oxide, carbon oxides (mostly carbon dioxide) are formed on the graphite anode [28,37]. 

Zinc metal dissolves in a solution of gaseous chlorine in water as follows ... 

The chlorine used to purify your drinking water was possibly made by electrolyzing molten Nad to produce liquid sodium and gaseous chlorine. 

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