Additive chlorination

Chlorine Addition. Chlorine addition and some chlorine substitution occurs at normal or slightly elevated temperatures in the absence of catalysts. The chlorination of molten naphthalene under such conditions yields a mixture of naphthalene tetrachlorides, a monochloronaphthalene tetrachloride, and a dichloronaphthalene tetrachloride, as well as mono- and dichloronaphthalenes (35). Sunlight or uv radiation initiates the addition reaction of chlorine and naphthalene resulting in the production of the di- and tetrachlorides (36). These addition products are relatively unstable and, at ca 40—50°C, they decompose to form the mono- and dichloronaphthalenes. 

Chlorinated polyethylene (CPE) has excellent o2one, oil, and heat resistance. In addition chlorinated polyethylene has replaced chloroprene elastomers. CPE has a lower specific gravity than chloroprene compounds and produces compounds that are similar to CR in properties but with lower costs. In addition, due to high levels of chlorine in the polymer, the flame resistance of the compounds of CPE are high. 

Addition. Chlorine adds to vinyl chloride to form 1,1,2-trichloroethane [79-00-5] (44—46). Chlorination can proceed by either an ionic or a radical path. In the Hquid phase and in the dark, 1,1,2-trichloroethane forms by an ionic path when a transition-metal catalyst such as ferric chloride [7705-08-0], FeCl, is used. The same product forms in radical reactions up to 250°C. Photochernically initiated chlorination also produces... 

Addition Chlorination. Chlorination of olefins such as ethylene, by the addition of chlorine, is a commercially important process and can be carried out either as a catalytic vapor- or Hquid-phase process (16). The reaction is influenced by light, the walls of the reactor vessel, and inhibitors such as oxygen, and proceeds by a radical-chain mechanism. Ionic addition mechanisms can be maximized and accelerated by the use of a Lewis acid such as ferric chloride, aluminum chloride, antimony pentachloride, or cupric chloride. A typical commercial process for the preparation of 1,2-dichloroethane is the chlorination of ethylene at 40—50°C in the presence of ferric chloride (17). The introduction of 5% air to the chlorine feed prevents unwanted substitution chlorination of the 1,2-dichloroethane to generate by-product l,l,2-trichloroethane. The addition of chlorine to tetrachloroethylene using photochemical conditions has been investigated (18). This chlorination, which is strongly inhibited by oxygen, probably proceeds by a radical-chain mechanism as shown in equations 9—13. 

The limited data available for 2,4-dichloroquinoline (Table X, line 9) show a substantially greater rate of methoxylation than for the 2- and 4-chloro analogs (Table X, line 6 and Table XI, line 2), as a result of activation (lowering of E ) by the additional chlorine substituent. Unequal mutual activation (cf. Section III, B, 2) by these substituents is indicated by the rate ratio of 1.9 1 for 4- to 2-substi-tution in the dichloro compound and of 25 1 for the two mono-chloro compounds. 

Amino-5(l/i)-quinoxalinone (123) gave 6,7-dichloro-5,8-quinoxalinequinone (124) (substrate sulfate, HCl, NaClOs, 0°C, 3 h >63% note additional chlorination). 

The core further extends via the additional chlorine (light grey) and cesium (solid black circle) ions. 

In addition, chlorine on the phthalide moiety also gives a bathochromic shift. Thus, 3 -cyclohexylamino-4,5,6,6, 7-pentachlorofluoran (22) 14 develops red color. 

Extreme pressure additives Chlorinated paraffins Lubricity agents... 

Subsequent chemistry leads to release of additional chlorine, and for purposes of discussion, it is here assumed that all of the available chlorine is eventually liberated in the form of compounds such as HC1, CIO, C102, and Cl2. The catalytic chain for ozone that develops is... 

Ag2C03 = 2 AgCl + 2HC10 + C02 Another way to increase the yield is to pass additional chlorine into soda or lime solutions of chlorine Cl2 + Na2C03 + H20 = NaClO +... 

During WWII, the Germans developed several illuminating mixtures, containing 14-28% of polyvinylchloride (either additionally chlorinated or not) together with 17-35% of magnesium powder, 50-61% of oxidizer and 1 to 5% of vaseline or synthetic wax (Ref 3)... 

In addition, chlorine derivatives are important as intermediates in the chemical industry, and there are numerous chlorine-containing pharmaceuticals for which no substitutes are presently available. Furthermore, organochlorine compounds, some very toxic, do occur naturally on a large scale. Clearly, however, we must endeavor to avoid adding unnecessarily to the natural load of toxins as the old adage goes, it is the dose that makes the poison.4 Certainly, problems exist that require an intelligent and chemically informed resolution, but the total ban advocated by some on the use of chlorine and chlorinated compounds is neither necessary nor acceptable. 

In the case of the hydrogen-chlorine reaction, the intermediate compound M, by J. W. Draper s hypothesis, is allotropic or active chlorine by E. Pringsheim s hypothesis,4 chlorine monoxide or some analogous compound. Having shown that the additive chlorine monoxide does not accelerate the reaction or abbreviate the period of induction, an imaginary intermediate compound was postulated of a more indefinite and vague form One naturally shirks vague hypotheses... 

Rubrolides A, B, and C (163-165) from the Northeastern Pacific tunicate Ritterella rubra are active against Staphylococcus aureus (MIC 9, 2 and 11 pg/disk) and Bacillus subtilis (MIC 9, 2 and 11 pg/disk). The most active compound, rubrolide B, contains an additional chlorine atom [126]. 

The standard disinfectant for many of the world s potable drinking water supply systems (ozone and others are also widely used) and the product of choice for large cooling systems, usually available as a gas for lowest cost, but can be provided by liquids such as sodium hypochlorite (bleach) or solids such as calcium hypochlorite or isocyanurates. Any process contaminant leak tends to increase the chlorine demand, requiring additional chlorine to maintain disinfection rate. Poor penetrant of biomass and significantly reduced efficiencies over pH 8.0. 

A quantum chemistry study of the reaction of chloroprene with CI2 has revealed two transition states for substitutive chlorination, which is consistent with two consecutive processes chlorination to give a carbocation followed by abstraction of the originally allylic proton. On the other hand, a single transition state was observed for additive chlorination. The potential barriers for the former process lay below that for the latter102. 

The common Caribbean octocoral Erythropodium caribaeorum has yielded several additional chlorinated diterpenes since the first survey (1). 

Another important side-reaction is the additive chlorination of propene to 1,2-dichloropropane ... 

A large proportion of the chlorine added to wastewater is consumed in oxidizing organic materials other than phenolic con-pounds. Thus, for example, in the work of Thompson and Dust cited above, the wastewater COD content averaged 20,400 mg/liter before and 10,400 mg/1 after treatment with chlorine at a rate of 2 g/liter. However, the OOD was further reduced to only 10,250 mg/liter upon the addition of 10 g/liter of additional chlorine. This result suggests that a portion of the organic content of the wastewater was resistant to chemical oxidation, as indicated above for phenolic compounds. 

General Procedure for Cascade Organocatalytic 1,4-Addition-Chlorination Sequence of Enals [101] (p. 114)... 

Decomposition of CD and HOC1 by reaction with organic material in municipal water supply systems sometimes makes it necessary to inject additional chlorine at outlying locations. 

The synthesis of 3-chloroisothiazole from 3-mercaptopropionitrile and chlorine58 (Scheme 19) may be envisaged as occurring by a similar mechanism with an additional chlorination-dehydrochlorination stage either before or after eyclization. 

It was shown later that the streptomycete can only modify rather than biosynthesize these compounds [66] and that all such derivatives, i.e. even genisteins (64,65) come from the soy meal or cotton seed and are not produced by streptomycetes. These results demonstrate clearly that flavonoids isolated from streptomycetes cultivated on media containing plant components, such as soy meal or cotton seed, always come from the cultivation medium and are not of microbial origin. The same effect was observed in S. griseus [65] producing two additional chlorinated genisteins (66,67). This also holds true [67] for isoflavone (68) isolated from Japanese soil. 

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