Phenol chlorination with

The compounds 2- (16) and 4-pyridone (38) undergo chlorination with phosphoms oxychloride however, 3-pyridinol (39) is not chlotinated similarly. The product from (38) is 4-chloropyridine [626-61-9]. The 2- (16) and 4-oxo (38) isomers behave like the keto form of the keto—enol tautomers, whereas the 3-oxo (39) isomer is largely phenolic-like, and fails to be chlotinated (38). 

The cleavage products of several sulfonates are utilized on an industrial scale (Fig. 3). The fusion of aromatic sulfonates with sodium hydroxide [1310-73-2J and other caustic alkalies produces phenohc salts (see Alkylphenols Phenol). Chlorinated aromatics are produced by treatment of an aromatic sulfonate with hydrochloric acid and sodium chlorate [7775-09-9J. Nitriles (qv) (see Supplement) can be produced by reaction of a sulfonate with a cyanide salt. Arenesulfonates can be converted to amines with the use of ammonia. This transformation is also rather facile using mono- and dialkylamines. 

Chlorination of Phenols. Industrially, the phenols are chlorinated without solvent. Chlorine reacts rapidly with phenol and with the chlorophenols, which makes it difficult to determine the relative reaction rates because of the superchi orin ation that sometimes results from an unsatisfactory chlorine dispersion. Studies have yielded the relative reaction rates iadicated ia Figure 1. 

The light chlorophenols, normally have a purity greater than 98.5%, but they often reach over 99%, or even 99.5% with direct phenol chlorination. The APHA color test is always below 100. For 2,4,6-ttichlorophenol, the 2,4,5-trichlorophenol content constitutes an essential quaUty index and should be under 20 mg/kg. None of the light chlorophenols contain any polychlorodibenzoparadioxins or polychlorodibenzofurans. 

In a series of articles, Caraculacu and coworkers described a method based on substitution of labile chlorines with phenol. IR [34] and UV [47] were used for determination of incorporated phenol. The published data indicate a detection limit of 2 and 0.5 labile chlorines per 1,000 monomer units. 

The simultaneous reaction of sulfur dioxide and chlorine with paraffins, named sulfochlorination, was discovered by Reed and Horn in the 1930s [9]. The primary products of this reaction are the alkanesulfochlorides [10], which can be saponified to alkanesulfonates by sodium hydroxide solution or treated with substituted phenolates to give plasticisers. In a short time the process was industrially realized to secure detergent production during World War II in Germany [11]. 

Raschig (2) Also called Raschig-Hooker. A two-stage regenerative process for making phenol from benzene. The benzene is first chlorinated with hydrochloric acid in the presence of air, at 200 to 260°C, over a copper catalyst on an alumina base ... 

Voudrias, E.A. "Effects of Activated Carbon on Free and Combined Chlorine with Phenols" Ph.D. Thesis University of Illinois, Urbana, 1985. 

This group of pesticides comprises different families of chemicals with her-bicidal action including substituted phenols, chlorinated aliphatic acids, chloro-phenoxy alkanoic acids, and substituted benzoic acids, which possess carboxyl or phenolic functional groups capable of ionization in aqueous media to yield anionic species [47,151,168-170]. 

When dissolved in a suitable solvent, uncross-linked poly(dichlorophosphazene) (3.21) functioned as a remarkable macromolecular reactant (reaction sequence (3)). When treated with organic nucleophiles such as the sodium salts of alcohols or phenols, or with primary or secondary amines, all the chlorine atoms along the polymer chain could be replaced by organic units. This is all the more remarkable because an average of 30,000 chlorine atoms per molecule are replaced. 

Honda and co-workers applied the above procedure to the formal total synthesis of enantiopure (-)-TAN1251A (45b), a muscarinic receptor antagonist, isolated from a culture of Penicillium thomii RA-89 [121]. The best yield of the spiroannulation reaction of the phenol 156 using PIDA was achieved by the reaction in (CF3)2CHOH similar to the Sorensen s procedure [119]. Incidentally, none of the desired product was obtained by the typical stepwise procedure using chlorination with NCS followed by Ag20 oxidation (Scheme 29). 

Condensation of compounds containing activated chlorine with amines or amino phenols [Eq. (5)]. 

Onodera et al. [8] examined the applicability of isotachophoresis to the identification and determination of chlorinated mono- and dicarboxylic acids in chlorinated effluents. Four electrolyte systems for the separation of acids were evaluated. The potential unit values in each system were determined for the chlorinated acids. A mechanism for the reaction of phenol with hypochlorite in dilute aqueous solutions is suggested, based on results from the isotachophoretic analysis of diethyl ether extracts taken from phenol treated with hypochlorite. 

Chlorinated Hydrocarbons Other Chlorinated Compounds. The substitution of chlorine atom for hydrogen in a compd greatly increases the anesthetic action of the derivative. In addn, the chlorine deriv is less specific than the parent hydrocarbon in its action, and may affect other tissues along with those of the central nervous system of this body. The chlorine deriv is generally quite toxic and may cause liver, heart Sc kidney damage. As a rule, unsaturated chlorine derivs are highly narcotic but less toxic than saturated derivs. Sax(Ref 4) has discussed in detail the toxicities Sc hazards of a number of chlorinated compds, including Chlorinated Diphenyls Chlorinated Hydrocarbons, Aromatic Aliphatic Chlorinated Naphthalenes Chlorinated Phenols Chlorinated Triphenyls others. 

Direct chlorination of vinyl chloride generates 1,1,2-tnchloroethane [79-00-5] from which vinylidene chloride required for vinylidene polymers is produced. Hydrochlorination of vinylidene chloride produces 1,1,1-trichloroethane [71-55-6], which is a commercially important solvent. Trichloroethylene and perchloroethylene are manufactured by chlorination, hydrochlorination, or oxychlorination reactions involving ethylene. Aromatic solvents or pesticides such as monochlorobenzene, dichlorobenzene, and hexachlorobenzene are produced by reaction of chlorine with benzene. Monochlorobenzene is an intermediate in the manufacture of phenol, insecticide DDT, aniline, and dyes (see Chlorocarbons a>td Chlorohydrocarbons.)... 

Dioxins and furans are not produced deliberately, but are produced unintentionally as byproducts of combustions of organic matter in the presence of chlorine. Dioxins and fiirans consists of 135 possible chlorinated dibenzoftnan and 75 chlorinated dibenzo-p-dioxins with Irom 1 to 8 chlorine substituents (Figure 18.2). PCDDs/DFs are found as byproducts during the manufacture of some industrial chemicals such as PCBs, polychlorinated naphthalenes, chlorinated phenols, chlorinated phenoxyacids, polychlorinated diphenyl ethers, polyvinyl chlorides, and chlorinated phenoxy-2-phenols (Hutzinger et al, 1985 Hryhorczuk et al, 1986 ATSDR, 2001 Masunaga et al. 

Phenols are highly activated towards electrophilic attack, which occurs readily at the 2- and 4-positions. For example, phenol reacts with bromine at room temperature in ethanol and in the absence of a catalyst to give 2,4,6-tribromophenol. Other electrophilic substitution reactions such as nitration, sulfonation, Friedel-Crafts, chlorination and nitrosation also proceed readily and hence care is needed to ensure multisubstitution does not occur. Protection of specific ring positions can also prevent unwanted substitution. Relatively mild conditions are usually employed. 

While the introduction of halogens into benzene takes place only with the aid of carriers, phenol reacts with chlorine or bromine at ordinary temperatures yielding chlor or brom phenols. By the action of bromine water on phenol the product is tri-brom phenol. 

Bisphenols (not to be confused with the diphenols), are formed by two phenols linked with a bridge (-CHj-, -O-or -S-) in the ortho position, which makes the product easier to tolerate. Bisphenols are often chlorinated to increase their disinfectant power. Dichlorophene, tetrachlorophene... 

A phenol derivative, phenolphthalein is prepared by the reaction of phenol with phthalic anhydride in the presence of sulphuric acid and used as an indicator for acidity or alkalinity. Chlorinated phenol is much safer than phenol. Chlorine gas reacts with phenol to add one, two or three chlorine atoms and to form, respectively, chlorophenol, 2,4-dichlorophenol and 2,4,6-trichlorophenol . The chlorination of phenol proceeds by electrophilic aromatic substitution. The latter two molecules are less soluble in water than phenol and appear to be a stronger antiseptic than phenol. Interestingly, in the first half of the past century, a bottle of antiseptic chlorophenols was a common attribute as a medicine in many homes. Its solution was used for bathing cuts, cleaning grazes, rinsing the mouth and gargling to cure sore throats. Nevertheless, it was revealed that its solution likely contains dioxins. 

Oxidation of 2-iodo-4,6-di(terr-butyl)phenol (702) with K3Fe(CN)e in aq. KOH (room temp., 20 min) also provided in 82% yield the corresponding benzoxete 703 probably through o-diphenoquinone. In contrast, similar oxidation of three 2-halo-4,6-di(ferf-butyl)phenols (704, 705 and 706) mainly afforded a dibenzofuran derivative 707 (81%), a mixture of 708 and 709 (23 and 53%, respectively) and a diaryl ether 710 (63%), respectively (Scheme 138). Clearly, iodine and bromine substituents promote the diaryl formation, while chlorine and fluorine substituents prefer to produce diaryl ethers. These results seem to be in good agreement with the ab initio calculations . 

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