Chlorine groups

Unlike other stabilizers, tin mercaptide, or the mercaptan that is formed after the HCl reacts with the mercaptide, can react with the allyhc chlorine to produce a sulfide (47), thus eliminating the labile chlorine groups and stopping the unzipping. 

D C Red No. 36 (27) is an unsulfonated pigment. It contains no groups capable of salt formation and is thus insoluble direcdy on coupling. Its chlorine group ortho to the azo group results in a stericaHy hindered molecule with low solubiUty and excellent light stabiUty. The unsulfonated dyes Citms Red No. 2 (8) and D C Red No. 17 (20) are insoluble in water but soluble in aromatic solvents. 

Catalytic Reaction. The desired reaction of the chlorine group on a chlorinated hydrocarbon is... 

Selective substitutions have been most studied in the pyrido[3,4-tf]pyridazine field. The 1,4-dichloro derivative (334) was more reactive than 1,4-dichlorophthalazine, and was expected from MO calculations to show a more reactive 4-chlorine group. In practice, however, almost equal amounts of monosubstitution products were observed on hydrolysis, although slight differences in the use of alkaline and acid conditions, or on hydrazination, have been reported (69CPB2266). Reaction of this 1,4-dichloro compound, or substituted... 

When polyethylene is chlorinated in the presence of sulphur dioxide, sulphonyl chloride as well as chlorine groups may be incorporated into the polymer Figure 10.10). This reaction is used to produce a useful elastomer (Hypalon, see Chapter 11). 

On the other hand, oxidizing fluonnating agents like silver difluoride, xenon difluoride, or bromine trifluoride replace one chlorine group and then cleave the sulfur-nitrogen bond [56],... 

It is well known that the trimeric phosphonitri-lic chloride can be polymerized, at 200-300°C, to poly(dichlorophosphazene) (1), hereafter this polymer will be referred to as chloropolymer. Since this polymer contains hydrolytically-unstable chlorine groups, these groups are usually replaced with various alcohols, phenols, or amines to import the polymer stability. In our laboratories, the substitution is generally with alcohols or phenols. The reaction scheme is shown in Figure 1. 

On the other hand, kcm> increases only slightly as more chlorine atoms are introduced. This result is somewhat surprising in the light of the marked decrease in the dimerization rate caused by the four meta buttressing chloro substituents. It can be understood to indicate that electrophilicity of the carbene center is increased as more chlorine groups are introduced on the phenyl rings (Table 9.14). Thus, the attack of a bulky substrate (e.g., chlorinated DPC) on the carbenic center must be severely restricted, while the rate of abstraction of a very small hydrogen atom from a very efficient H donor is still controlled by the electrophilicity of the carbenic center. 

The chlorine group of iV-chloroimines [21] and C-chloro-A-benzylidene-anilines [22] react with Grignard reagents in fair to good yields to give the corresponding imines as described in Eqs. (11) and (12). 

DDT p,p -dichloro-diphenyl-trichloroethane. deacetylation removal of acetyl group, dealkylation removal of alkyl group, deaminate removal of amine group, dechlorination removal of chlorine group, de-ethylation removal of ethyl group, dehalogenation removal of halogen atom(s). 

There is a difference in the ease with which the two chlorine groups in 4,10-dichloro-l,7-phenanthroline are replaced by nucleophiles. For example, the 10-chloro substituent reacts with sodium ethoxide five hundred times faster than the 4-chloro substituent. Consequently, 4-chloro- 10-ethoxy, 4-chloro- 10-methoxy-, 4-chloro- 10-anilino, and 4-chloro-10-hydroxy-1,7-phenanthrolines can be prepared from 4,10-dichloro-l,7-phenanthroline.97, 171,172,336 The exceptional reactivity of the 10-chloro group is attributed to relief of strain in the transition state in its reaction with nucleophilic reagents.336 With excess of the nucleophilic reagents, both chlorines in 4,10-dichloro-l,7-phenanthroline are replaced.171, 172,336... 

Chlorine groups in chloro- and dichlorobenzo[6][l,8]phenanthrolines have likewise been replaced by a variety of amines.180... 

The chlorine groups in 4-chloro-1,10-phenanthroline and 4,7-dichloro-1,10-phenanthroline are replaced by cyano groups on fusion with potassium cyanide342 while 2-cyano- and 5-cyano- 1,10-phenanthrolines have been obtained from 2-chloro and 5-bromo-l,10-phenanthrolines, respectively, by reaction with cuprous cyanide.267... 

Simple alkyl and aryl derivatives of nickel(II) with monodentate phosphines are, in general, too unstable to be isolated in the solid state as pure compounds. However, it has been found that a considerable stabilization occurs when the carbon cr-bonded to nickel(II) is part of either an alkynic group, a fluorinated or chlorinated group, or an orf/io-substituted phenyl group. 

Figure 5 shows a more detailed analysis of variations of homologous chlorine groups with depth in sediment. Again two seemingly different systems are revealed for the lower portion of Twelve Mile Creek and for Lake Hartwell. The Twelve Mile Creek samples (G26 and G33) showed DCB... 

Figure 3. Weight-percent data for DCBsy TrCBs, TCBs, and PHHCBs versus distance from the PCB source for the top sections of six Twelve Mile Creek-Lake Hartwell sediment cores. Peaks containing two or more congeners were assigned to a homologous chlorination group on the basis of which congener accounted for most of the total peak mass (as reported in references 25 and 26). Peaks that could not be accurately classified (26, 28, and 31) were...

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