Chlorinated naphthalenes, production

Uses Chlorinated naphthalenes were formerly used in the production of electric condensers, insulating electric condensers, electric cables, and wires additive for high pressure lubricants. 

The use of computers has made it possible to characterise models with large numbers of individual steps. Andersson and Lamb [25] used an analogue computer to estimate parameters in a model with 15 reactions which described naphthalene production by hydrodealkylation. Also, they were able to predict temperature distributions and effluent concentrations for a commercial reactor. Kurtz [26] took 200 simultaneous reactions into account in an experimental study of the gas-phase chlorination of methyl chloride. Model discrimination and parameter estimation for catalytic processes are discussed in a comprehensive review by Froment [27]. 

The reaction of benzyne with hexachlorobenzene was tried (Fields and Meyerson, 1967d). This compound, in spite of steric crowding, is stable to heat (Krynitzky and Carhart, 1949) and to electron impact in the mass spectrometer (Meyerson and Fields, 1966c), as well as inert chemically. At 690° for 35 sec. it was recovered unchanged. With phthalic anhydride in a 2 1 mole ratio, under the same conditions, it gave about a 5% conversion to hexaehlorobiphenyl, the benzyne insertion product. Absence of any chlorinated naphthalene indicates the difficulty of forming a 1,4- or 1,2-adduct of benzyne with the completely shielded benzene ring. 

Uses Chlorodiphenyls are used in combination with chlorinated naphthalenes, which are stable, thermoplastic, nonflammable, and are used in electric cables and wires in the production of electric condensers, additives for extreme pressure lubricants, and as a coating in foundry. Chlorodiphenyls are widely used in the manufacture of herbicides, lacquers, paper, plasticizers, resins, rubbers, textiles, wood preservatives, and electric equipments. 

SAFETY PROFILE Questionable carcinogens that can cause tumors of the liver. Severe irritants by ingestion, inhalation, and skin contact. The action of the chlorinated naphthalenes on the body is quite similar to that of the chlorinated biphenyls, the chief effects being the production of chloracne of the skin, and systemically an acute yellow atrophy of the liver. When heated to decomposition they emit toxic fumes of CT. 

Most probably, it is mainly lower chlorinated naphthalenes that are still used today. These have been used, for example, as glues for plywood in Finnish plywood plants [33]. Lower chlorinated naphthalenes were used in a product for wood preservation against bugs in Sweden until 1987 when it was stopped, as it was shown to contain higher chlorinated naphthalenes than declared [Asplund, unpublished data]. From our experience, chlorinated naphthalenes mixtures of low chlorination degree also contain small amounts of more highly chlorinated congeners [Asplund and Jakobsson,unpublished]. 

Except for 1 -monoCN, which is a liquid at room temperature, the chlorinated naphthalenes are crystalline compounds. The melting point increases with increasing chlorine substitution with considerable variation within each homolo-gue group, cf. Table 2. The commercial PCN products, which occur as complex mixtures of isomers and homologues, are generally waxes with high compatibility with other materials. The solid products melt to liquids of extremely low viscosity [1]. 

Lahaniatis et al. found that a thermal degradation of toxaphene at 400°C to 800°C leads to the formation of aromatic compounds, among them tri- to hexa-chlorobenzenes, low-chlorinated naphthalenes, biphenyls, and even dibenzofu-rans [176]. The major processes of degradation seem to be dechlorination and dehydrochlorination [54]. However, Chandurkar and Matsumura reported that at least some hydroxylated toxaphene metabolites are formed [81]. So far, only very few oxidation products of toxaphene have been identified [177,178,179] which seem to be rather unstable [177]. 

Chlor Naphthalenes.—Another series of reactions which support the view just discussed, that in naphthalene there are present two nuclei either one of which is a benzene ring, is found in Laurent s work on the chlorine substitution products of naphthalene. When naphthalene is chlorinated it yields different chlor naphthalenes. Two of these are important in this place, viz., a tetra-chlor naphthalene, C10H4CI4 and a penta-chlor naphthalene, C10H3CI5. Now the first one must have all four chlorines linked to one nucleus because on oxidation it yields ortho-phthalic acid, as below. The penta-chlor compound must of necessity have at least one of the chlorines linked to the second nucleus as only four are possible of being linked to one nucleus. Now this compound on oxidation yields not mono-chlor phthalic acid but tetra-chlor phthalic acid. The reactions may be represented as follows ... 

Halogenated naphthalenes in Teltow Canal sediments are specific pollutants reflecting the industrial point source emission. Chlorinated naphthalenes are known environmental pollutants, which are emitted due to their usage as technical additives, as a result of pyrolytic processes or as an impurity associated with PCB products (Haglund et al. 1993 Jamberg et al. 1993). In the extractable fraction mono- and dichlorinated naphthalenes were determined with total concentrations between 120 and 493 pg/kg. The peak pattern was similar to the congener distribution of technical mixtures (Halowax 1000, Halowax 1001) (Falandysz 1998). The concentration of 1-bromonaphthalene ranged between the limit of quantification (LOQ) and 250 pg/kg (see Table 1). 

Octachioronaphthaiene(Haiowax1051 [CAS 2234-13-1]) By analogy to other chlorinated naphthalenes, workers overexposed by inhalation or skin contact may experience chloracne and liver damage. 0.1 mg/m , S Pale yellow solid with an aromatic odor. Vapor pressure is less than 1 mm Hg at 20°C (68 F). Not combustible. Thermal-breakdown products include hydrogen chloride. 

For the determination of anthraquinone, added as a stabilizer in capacitor dielectrics (using chlorinated diphenyls, chlorinated naphthalenes and mineral oils as impregnants) a solvent consisting of a 3 2 mixture of chloroform and methanol with magnesium chloride and hydrochloric acid was able to dissolve all materials used.< ) Owing to the presence of the strong acid, the reduction of anthraquinone is shifted to potentials near 0 0 V. At these potentials the waves of the chlorinated products do not interfere. 

Mixtures of tri- and tetrachloronaphthalenes comprise the bulk of the market use as the paper impregnant in automobile capacitors secondary uses of mono- and dichloronaphthalenes include oil additives for engine cleaning and fabric dyeing. Annual production of all chlorinated naphthalenes in the USA has probably been <270 metric tons in recent years (Sittig, 1980). 

Substitution. Substitution products retain the same nuclear configuration as naphthalene. They are formed by the substitution of one or more hydrogen atoms with other functional groups. Substituted naphthalenes of commercial importance have been obtained by sulfonation, sulfonation and alkah fusion, alkylation, nitration and reduction, and chlorination. 

Addition. The most important addition products of naphthalene are the hydrogenated compounds. Of less commercial significance are those made by the addition of chlorine. 

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. 

Polychloiinated naphthalenes (PCNs) are halogenated aiomatic hydiocaibons that are no longer produced. They can be synthesized by the chlorination of naphthalene. The commercial products were graded and sold according to their chlorine content (wt %), and used as waxes and impregnants (for... 

Cl Sulphur Black 1, which is produced from the relatively simple intermediate 2,4-dinitrophenol and aqueous sodium polysulphide. A similar product (Cl Sulphur Black 2) is obtained from a mixture of 2,4-dinitrophenol and either picric acid (6.148 X = N02) or picramic acid (6.148 X = NH2). A black dye possessing superior fastness to chlorine when on the fibre (Cl Sulphur Black 11) can be made from the naphthalene intermediate 6.149 by heating it in a solution of sodium polysulphide in butanol. An equivalent reaction using the carbazole intermediate 6.150 gives rise to the reddish blue Cl Vat Blue 43 (Hydron blue). This important compound, which also possesses superior fastness properties, is classified as a sulphurised vat dye because it is normally applied from an alkaline sodium dithionite bath. Interestingly, inclusion of copper(II) sulphate in the sulphurisation of intermediate 6.150 leads to the formation of the bluish black Cl Sulphur Black 4. 

Chemical/Physical. An aqueous solution containing chlorine dioxide in the dark for 3.5 d oxidized naphthalene to chloronaphthalene, 1,4-dichloronaphthalene, and methyl esters of phthalic acid (Taymaz et ah, 1979). In the presence of bromide ions and a chlorinating agent (sodium hypochlorite), major products identified at various reaction times and pHs include 1-bromonaphthalene, dibromonaphthalene, and 2-bromo-l,4-naphthoquinone. Minor products identified include chloronaphthalene, dibromonaphthalene, bromochloronaphthalene, bromo-naphthol, dibromonaphthol, 2-bromonaphthoquinone, dichloronaphthalene, and chlorodibromo-naphthalene (Lin et ah, 1984). 

Chemical/Physical. Under atmospheric conditions, the gas-phase reaction of o-xylene with OH radicals and nitrogen oxides resulted in the formation of o-tolualdehyde, o-methylbenzyl nitrate, nitro-o-xylenes, 2,3-and 3,4-dimethylphenol (Atkinson, 1990). Kanno et al. (1982) studied the aqueous reaction of o-xylene and other aromatic hydrocarbons (benzene, toluene, w and p-xylene, and naphthalene) with hypochlorous acid in the presence of ammonium ion. They reported that the aromatic ring was not chlorinated as expected but was cleaved by chloramine forming cyanogen chloride. The amount of cyanogen chloride formed increased at lower pHs (Kanno et al., 1982). In the gas phase, o-xylene reacted with nitrate radicals in purified air forming the following products 5-nitro-2-methyltoluene and 6-nitro-2-methyltoluene, o-methylbenzaldehyde, and an aryl nitrate (Chiodini et ah, 1993). 

Naphthalene-catalyzed (5%) lithiation of the chlorinated thioether 203 in the presence of pivalaldehyde gave, after hydrolysis, the product 204 in which, together with the... 

Chlorinated ketals 221 were lithiated using a catalytic amount (8%) of naphthalene in THE at —78°C to generate the corresponding masked lithium 5-enolates 222, which upon treatment with different electrophiles in THE at temperatures ranging between —78 and 20 °C, and final hydrolysis with water, afforded protected functionalized ketals 223 (Scheme 76). The application of this methodology to the chlorinated dithiane 224, under the same reaction conditions, gave the intermediate 225 and finally products 226 (Scheme 76) -... 

A special case of functionalized aryllithium reagents appears when the corresponding aryl group bears a ketal moiety at the benzylic position due to the lability of the benzyUc carbon-oxygen bonds. However, working under Barbier-type conditions and using naphthalene (10%) as the electron carrier catalyst, the reaction of chlorinated materials 242 afforded, after hydrolysis with water, the corresponding polyfunctionalized products 243 (Scheme 81). ... 

---