Napthalenes

Naphthalene (qv) from coal tar continued to be the feedstock of choice ia both the United States and Germany until the late 1950s, when a shortage of naphthalene coupled with the availabihty of xylenes from a burgeoning petrochemical industry forced many companies to use o-xylene [95-47-6] (8). Air oxidation of 90% pure o-xylene to phthaUc anhydride was commercialized ia 1946 (9,10). An advantage of o-xylene is the theoretical yield to phthaUc anhydride of 1.395 kg/kg. With naphthalene, two of the ten carbon atoms are lost to carbon oxide formation and at most a 1.157-kg/kg yield is possible. Although both are suitable feedstocks, o-xylene is overwhelmingly favored. Coal-tar naphthalene is used ia some cases, eg, where it is readily available from coke operations ia steel mills (see Steel). Naphthalene can be produced by hydrodealkylation of substituted naphthalenes from refinery operations (8), but no refinery-produced napthalene is used as feedstock. Alkyl naphthalenes can be converted directiy to phthaUc anhydride, but at low yields (11,12). 

Henkel Rearrangement of Benzoic Acid and Phthalic Anhydride. Henkel technology is based on the conversion of benzenecarboxyhc acids to their potassium salts. The salts are rearranged in the presence of carbon dioxide and a catalyst such as cadmium or zinc oxide to form dipotassium terephthalate, which is converted to terephthahc acid (59—61). Henkel technology is obsolete and is no longer practiced, but it was once commercialized by Teijin Hercules Chemical Co. and Kawasaki Kasei Chemicals Ltd. Both processes foUowed a route starting with oxidation of napthalene to phthahc anhydride. In the Teijin process, the phthaHc anhydride was converted sequentially to monopotassium and then dipotassium o-phthalate by aqueous recycle of monopotassium and dipotassium terephthalate (62). The dipotassium o-phthalate was recovered and isomerized in carbon dioxide at a pressure of 1000—5000 kPa ( 10 50 atm) and at 350—450°C. The product dipotassium terephthalate was dissolved in water and recycled as noted above. Production of monopotassium o-phthalate released terephthahc acid, which was filtered, dried, and stored (63,64). 

E] Compared napthalene sublimination to aqueous absorption to obtain fBerl saddles, = diameter of sphere with same surface area as pacldug piece. Lc — operating void space = e —, where e =... 

This is consistent with the observed products of oxidation, i.e. benzyl alcohol, benzaldehyde and benzoic acid and with the observed oxidation of cyclohexane. Radical-cations are, however, probably formed in oxidation of napthalene and anthracene. The increase of oxidation rate with acetonitrile concentration was intepreted in terms of a more reactive complex between Co(III) and CH3CN. The production of substituted benzophenones at high CH3CN concentration indicates the participation of a second route of oxidation. 

Lee K, SM Resnick, DT Gibson (1997) Stereospecific oxidation of R) and (S)-l-indanol by napthalene dioxygenase from Pseudomonas sp. strain NCIB 9816-4. Appl Environ Microbiol 63 2067-2070. 

It has become clear that benzoate occupies a central position in the anaerobic degradation of both phenols and alkylated arenes such as toluene and xylenes, and that carboxylation, hydroxylation, and reductive dehydroxylation are important reactions for phenols that are discussed in Part 4 of this chapter. The simplest examples include alkylated benzenes, products from the carboxylation of napthalene and phenanthrene (Zhang and Young 1997), the decarboxylation of o-, m-, and p-phthalate under denitrifying conditions (Nozawa and Maruyama 1988), and the metabolism of phenols and anilines by carboxylation. Further illustrative examples include the following ... 

Aromatic compounds in the series, benzene, napthalene, anthracene, tetracene, etc., form crystals. However, benzene melts below room temperature. Napthalene, although solid at room temperature, has a high vapor pressure. Therefore, the first in the series whose crystals are stable enough at room temperature for extensive hardness studies is anthracene. 

Clearly, the hardnesses of thermoplastic polymers are not intrinsic. They depend on various extrinsic factors. Only trends can be cited. For example, as the molecular weight in polyethylene materials increases, they become harder. And, as the molecular aromaticity increases, a polymeric material becomes harder. Thus, higher molecular weight anthracene is harder than napthalene and more aromatic Kevlar is harder than polymethacrylate. 

It is now well established that when a surface presents electron donor or electron acceptor sites, it is possible to ionize molecules of relatively high electron affinity (> 2 eV) or low ionization potential values, resulting in paramagnetic radical ions. For instance anthracene and perylene are easily positively ionized on alumina (7 ) (IP = 7.2 and 6.8 eV respectively). The adsorption at room temperature of benzenic solution of perylene, anthracene and napthalene on H-ZSM-5 and H-ZSM-11 samples heated up to 800°C prior to adsorption did not give rise to the formation of the corresponding radical cation. For samples outgassed at high... 

Goldstein, J.A. (1980) Halogenated Biphenols, Terpyhenyls, Napthalenes, Dibenzodioxins and Related Products, (ed R.D. Kimbrough). Elsevier, North Holland, New York, pp. 151-190. 

Perylene and perinone pigments are chemically related. The group of perylene pigments is derived from perylene-3,4,9,10-tetracarboxylic acid 67, while perinone pigments are derivatives of napthalene-l,4,5,8-tetracarboxylic acid 68 ... 

We note here, that the eclipsed conformation of N204 can be viewed as being a sigma aromatic system geometrically similar to the pi aromatic system napthalene as illustrated below ... 

TABLE 22. 13C and 15N solution and solid state NMR data for l,8-bis(dimethylamino)napthalene and... 

We welcome a study of file tautomerically frozen species, some synthetically and calorimetrically suitable alkoxynitrosobenzenes, their p-benzoquinone O-alkyloxime isomers and file corresponding napthalene analogs. 

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