Source of chlorine

The preference is for a process based on ethylene rather than the more expensive acetylene and chlorine rather than the more expensive hydrogen chloride. Electrolytic cells are a much more convenient and cheaper source of chlorine than hydrogen chloride. In addition, we prefer to produce no byproducts. 

There are numerous misconceptions about the sources of various chemical elements in waste, particularly those that are potential acid formers when the waste is incinerated or mechanically converted and used as a refuse-derived fuel. For example, it is often mistakenly stated that the source of chlorine in waste, hence a potential source of HCl emissions, is poly(vinyl chloride). The relative contents of selected, potentially acid-forming elements in the organic portion of a sample of waste collected from various households in one U.S. East Coast city is given in Table 2 (17). In this city, a chief source of chlorine in the waste is NaCl, probably from food waste. 

The recent (since 1993) tightness of the chlorine market, which was accompanied by rising chlorine prices, sparked interest in alternative sources of chlorine, ie, HCl and EDC, where these are available. Some plants no longer operate in a strictly balanced mode, but instead operate with more than half of thek EDC made from oxychlorination (owing to importation of HCl or EDC as a chlorine source, thus bypassing dkect chlorination). The ideal situation is one in which the plant can adapt to any feed combination, allowing operation at the optimum mix of feedstocks as determined by minimization of the sum of raw material and operating costs. 

Other Uses. As a biocide, chlorine dioxide is more effective than chlorine over a wider pH range. Chlorine dioxide is also less corrosive and more compatible with some materials of constmction. Chlorine dioxide has a wide variety of small appHcations in drinking water, food processing (qv), cooling towers, and oil recovery. In these areas, chlorite is the preferred source of chlorine dioxide. 

The chlorophylls produced by bacteria, algae and plants are a natural source of chlorins. The isolation of chlorophylls from natural material is known to be difficult because of their extreme sensitivity to various reactions, such as enolization, epimerization, allomerization, de-methoxycarbonylation, solvolysis, demctalation, dephytylation, photooxidation, etc. Often the... 

With 77 % aqueous acetic acid, the rates were found to be more affected by added perchloric acid than by sodium perchlorate (but only at higher concentrations than those used by Stanley and Shorter207, which accounts for the failure of these workers to observe acid catalysis, but their observation of kinetic orders in hypochlorous acid of less than one remains unaccounted for). The difference in the effect of the added electrolyte increased with concentration, and the rates of the acid-catalysed reaction reached a maximum in ca. 50 % aqueous acetic acid, passed through a minimum at ca. 90 % aqueous acetic acid and rose very rapidly thereafter. The faster chlorination in 50% acid than in water was, therefore, considered consistent with chlorination by AcOHCl+, which is subject to an increasing solvent effect in the direction of less aqueous media (hence the minimum in 90 % acid), and a third factor operates, viz. that in pure acetic acid the bulk source of chlorine ischlorineacetate rather than HOC1 and causes the rapid rise in rate towards the anhydrous medium. The relative rates of the acid-catalysed (acidity > 0.49 M) chlorination of some aromatics in 76 % aqueous acetic acid at 25 °C were found to be toluene, 69 benzene, 1 chlorobenzene, 0.097 benzoic acid, 0.004. Some of these kinetic observations were confirmed in a study of the chlorination of diphenylmethane in the presence of 0.030 M perchloric acid, second-order rate coefficients were obtained at 25 °C as follows209 0.161 (98 vol. % aqueous acetic acid) ca. 0.078 (75 vol. % acid), and, in the latter solvent in the presence of 0.50 M perchloric acid, diphenylmethane was approximately 30 times more reactive than benzene. 

The principal use of sodium chlorate is as a source of chlorine dioxide, C102. The chlorine in C102 has oxidation number +4, and so the chlorate must be reduced to form it. Sulfur dioxide is a convenient reducing agent for this reaction ... 

Aldehydes can be directly converted to acyl chlorides by treatment with chlorine however, the reaction operates only when the aldehyde does not contain an a hydrogen and even then it is not very useful. When there is an a hydrogen, a halogenation (12-4) occurs instead. Other sources of chlorine have also been used, among them S02Cl2 and r-BuOCl. The mechanisms are probably of the free-radical type. V-Bromosuccinimide, with AIBN (p. 912) as a catalyst, has been used to convert aldehydes to acyl bromides. 

There are many natural sources of chlorine compounds, which is not surprising considering that it is the 20th most abundant element. Salt and salt water are widely available the Great Salt Lake contains 23% salt, and the Dead Sea contains about 30%. Because salt is so abundant, most minerals that contain chlorine are not important sources for economic reasons. Bromine is found in some salt brines and in the sea, as are some iodine compounds. 

Additional details regarding the samples were obtained by inferring from the elemental analysis the amount of cobalt present as oxide and chloride. The only source of chlorine in these samples is the cobalt chloride dopant. Thus, based on the chlorine concentration we can estimate the amount of cobalt that must be present as cobalt chloride. For example, film t5 is calculated to contain 78.7% of the cobalt as chloride and by difference about 21% as cobalt oxide. Film 7 (which is film 5 after both a 24 hour soa)c and a 24 hour extraction with DMAc) contains 20% of the cobalt... 

To use potassium nitrate in colored flame mixtures, it is necessary to include magnesium as a fuel to raise the flame temperature. A source of chlorine is also needed for formation of volatile BaCl (green), or SrCl (red) emitters. The presence of chlorine in the flame also aids by hindering the formation of magnesium oxide and strontium or barium oxide, all of which will hurt the color quality. Shidlovskiy suggests a minimum of 15% chlorine donor in a color composition when magnesinm metal is nsed as a fuel [5]. 

In the case of the chlorine reactions, the involvement of H+ in the second step means that these reactions are efficient sources of chlorine atoms only at a pH less than about 4. Br can be converted to Br atoms in reactions analogous to those for chlorine, but in this case, generation of atomic bromine occurs up to a pH of about 11 (Zellner and Herrmann, 1995). 

Fig. 53a). Take two small U-tubes, close their upper openings with rubber stoppers, and their side offtakes with short rubber tubes having glass rods inserted into them. Weigh the tubes. Fill one U-tube with the prepared activated carbon, and the other with ordinary charcoal. Again weigh both tubes and connect them by a tee-piece to a source of chlorine.

The chlorination reactions described in this example may also take place under combustion conditions. Organic chlorine compounds provide a source of chlorine atoms, which readily abstract hydrogen atoms from other organic hydrocarbons. This serves to extend the radical chain, and accelerates the production of heavier hydrocarbons with the possible formation of soot. 

A major source of chlorine gas, Cl2, is from the electrolysis of brine, which is concentrated saltwater, NaCl(aq). What other two products result from this electrolysis reaction Write the balanced chemical equation. 

Sulfuryl chloride, which is usually a source of chlorine radicals, reacts with 6-phenylpyran-2-one to give the 3,5-dichloro derivative (63ZOR3434). 

Few interactions of radicals with the pyran-4-one family are recorded. Sulfuryl chloride (usually a source of chlorine radicals) converts flavone into the 2,3,3-trichloro derivative (455) which on catalytic hydrogenolysis in the presence of a base gives 3-chloroflavone (70CC380). Chromone reacts with sulfuryl chloride to give 2,3-dichlorochromanone (456) (67CHE624). 

A different experimental approach to the study of chlorine atom reactions with olefins will be mentioned briefly. Wijnen(l06) has studied the photolysis of phosgene as a source of chlorine atoms in the presence of ethylene, and Guercione and Wijnen (49) have carried out similar experiments with propylene. The features of these processes are quite different from those encountered in photochlorination in the presence of molecular chlorine, since the chain propagating reaction (3) cannot occur. Although in the photolysis of phosgene Cl and COC1 are initially formed, it appears that all COC1 radicals further decompose into CO and Cl. 

The photolysis of phosgene as a source of chlorine atoms has so far been used only very little. However, it opens up an alternative experimental approach which may prove useful in the study of some aspects of chlorine atom addition reactions. 

The cheapest source of chlorine is the hazardous, yellow-green CI2 gas, supplied under pressure as a liquid. However, the supply of chlorine bottles (cylinders), the maintenance of a chlorinator (which permits the conversion of liquid chlorine into lower pressure gaseous chlorine), and the eductor and piping system is costly. It also requires first class health and safety handling procedures. 

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