Chlorine substitution

Chlorine substitutes the hydrogen of methane giving successively the chlorides CH3CI, CH2CI2, CHCI3 and CCI4. It is to be noted that if a hydrocarbon is unsaturated, chlorine atoms will first add to the double or triple bond after which substitution may occur. 

Chemical Properties and Industrial Uses. Chloroacetic acid has wide appHcations as an industrial chemical intermediate. Both the carboxyhc acid group and the cx-chlorine are very reactive. It readily forms esters and amides, and can undergo a variety of cx-chlorine substitutions. 

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. 

If the production of vinyl chloride could be reduced to a single step, such as dkect chlorine substitution for hydrogen in ethylene or oxychlorination/cracking of ethylene to vinyl chloride, a major improvement over the traditional balanced process would be realized. The Hterature is filled with a variety of catalysts and processes for single-step manufacture of vinyl chloride (136—138). None has been commercialized because of the high temperatures, corrosive environments, and insufficient reaction selectivities so far encountered. Substitution of lower cost ethane or methane for ethylene in the manufacture of vinyl chloride has also been investigated. The Lummus-Transcat process (139), for instance, proposes a molten oxychlorination catalyst at 450—500°C to react ethane with chlorine to make vinyl chloride dkecfly. However, ethane conversion and selectivity to vinyl chloride are too low (30% and less than 40%, respectively) to make this process competitive. Numerous other catalysts and processes have been patented as weU, but none has been commercialized owing to problems with temperature, corrosion, and/or product selectivity (140—144). Because of the potential payback, however, this is a very active area of research. 

Same stmcture as isoviolanthrone violet, but the chlorine substitution pattern is Same ring stmcture as isoviolanthrone violet, but one bromo substituent rather... 

PVC, the polymerization product of chlorine-substituted ethylene derivatives, is probably the most widely used plastic for process plant construction. It is available in four different types rigid, high impact, high temperature and plasticized. 

The haloform reaction of unsymmetrical perfluoroalkyl and co-hydroper-fluoroalkyl trifluororaethyl ketones gives the alkane corresponding to the longer alkyl chain [54] (equation 53) If the methyl group contains chlorine, the reaction can take different pathways, leading to loss of chlorine (equation 54), because of the variable stability of the chlorine-substituted methyl carbanions in alkali. 

Table 4. Yield of chlorine substitution by azoturo in chloroarene complexes...

Oxidation of methyl perfluoroalkyl sulphones with refluxing aqueous potassium permanganate produced the perfluorinated alkanesulphonic acid in 85% yield as the potassium salt (equation 86). On the other hand, attempted oxidation with sodium hypochlorite caused only chlorine substitution (equation 87). Reaction of the new sulphone with aqueous hydroxide gave the same perfluoroalkane sulphonic acid salt (equation 88). 

Some PCB congeners have coplanar structures (see, e.g., 3,4,3, 4 -tetrachloro-biphenyl in Figure 6.1). The coplanar conformation is taken up when there is no chlorine substitution in ortho positions. If there is substitution of chlorine in only one ortho position, the molecule may still be close to coplanarity, because of only limited interaction between Cl and H on adjoining rings. Substitution of chlorines in... 

Chlorine-substituted quinones, and especially chloranil (i.e., tetrachloro-quinone), are predominantly transfer agents rather than inhibitors. Nuclear substitution as in the first step of reaction (55) may be involved with subsequent transfer of a chlorine atom to a monomer molecule. ... 

In the free radical polymerization of 1,3-dienes, 1,4 addition dominates 1,2 addition. The proportion of 1,2 (and 3,4 )units decreases in passing from butadiene to its methyl and chlorine substitution products isoprene, 2,3-dimethylbutadiene and chloroprene. The trans configuration of the 1,4 unit from butadiene is formed preferentially, the proportion of trans increasing rapidly with lowering of the polymerization temperature. 

Furukawa K, N Tomizuka, A Kamibayashi (1979) Effect of chlorine substitution on the bacterial metabolism of various polychlorinated biphenyls. Appl Environ Microbiol 38 301-310. 

Sensitivity for fluorine-substituted < chlorine-substituted < broaine-substituted < iodine-substituted coapounds... 

At the second stage of chlorine substitution in the tetramers there is a greater statistical probability for the incoming nucleophile to attack the phosphorus adjacent to =P(C1)(NHR), viz. P4 or P8, rather than the remote phosphorus, viz. P6 (Fig. 9). However, this statistical effect is countered by the electron releasing effect of the substituent already present on P2, which tends to deactivate P2 as well as P4 and P8 towards further nucleophilic substitution. It is observed that reactive amines such as dimethylamine (94) or ethylamine (95) react with N4P4C18 and... 

Besides benzyl chloride, methyl- and/or chlorine-substituted benzyl chlorides, phenethyl chloride, etc. are also successfully employed to give 2 -diaralkylaminofluorans in excellent yield. However, aryl halides such as chlorobenzene and bromobenzene hardly enable the reaction, though aryl iodides such as iodobenzene give 2 -diarylaminofluorans in low yield. 

Figure 7 Tetrahydroimidazo[4,S,1 -jk] [1,4]benzodiazepin-2(1 H)-one (TIBO) derivatives (A) R82913 and (B) R86183 (with a chlorine substituted in the 9- or 8-position, respectively).

Electronic states and photodissociation dynamics of chloromethyl radical have been studied recently.114-117 Because of the chlorine substitution, there are several low-lying valence excited states (such as l2Ai and 22Bi, which mainly involve the orbitals on the CC1 bond) in addition to the 3s Rydberg state (22Ai), and more dissociation channels are available. 

Investigation of Chlorine Substitution Effects in the Claisen-Schmidt Condensation of 2 -Hydroxyacetophenone with Chlorobenzaldehydes Over MgO... 

Chlorine substitution at the 3-position leads to CF3 carbon chemical shifts at a progressively higher field (Scheme 5.7), whereas the proton and carbon chemical shifts for the CH2 group of CF3CH2C1 are affected more by the chlorine substituent than by the CF3 group. 

Ammonia (NH3) and hypochlorite ion (OC1-) combine to produce three different chloramine species—that is, compounds that are derivatives of ammonia in which one or more of the hydrogen atoms has been replaced by a chlorine atom. In order of increasing degree of chlorine substitution, these chloramines are named monochloramine (NH2CI), dichloramine (NHCh), and nitrogen trichloride (NCI3) ... 

Chemicals degraded by WRF include pesticides such as organochlorines DDT and its very toxic metabolite DDE [8, 9] and organophosphate pesticides such as chlorpyrifos, fonofos and terbufos [10] polychlorinated biphenyls (PCBs) of different degrees of chlorine substitution [11-13], some even to mineralization [14, 15] diverse polycyclic aromatic hydrocarbons (PAHs) in liquid media and from contaminated soils or in complex mixtures such as creosote [16-18] components of munition wastes including TNT and its metabolites DNT [19-23], nitroglycerin [24] and RDX [25]. 

A) functionalization/linker attachment (B) introduction ofthe first building block (C) attachment of cyanuric chloride (D) stepwise chlorine substitution (E) cleavage. 

Kaiser, K.L.E. (1983) A non-linear function for the calculation of partition coefficients of aromatic compounds with multiple chlorine substitution. Chemosphere 12, 1159-1165. 

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