Napthalene oxidation

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 Henkel technology is obsolete and is no longer practiced, but it was once commercialized by Teijin Hercules Chemical Co. and Kawasaki Kasei Chemicals Ltd.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). 

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. 

Potassium chlorate, Sulfur, Zinc powder, Sodium bicarbonate Zinc powder, Zinc oxide, Hexachoroethane Potassium chlorate, Paranitranihne, Lactose, Powdered sugar Potassium chlorate, Aniline, Napthalene azodimethyl Potassium chlorate, Napthalene, Azodimethyl aniline, Auramine, Sodium bicarbonate, Sulfur... 

Andreikov, E.I. and R.L. Volkov. 1981. Catalytic properties of vanadium oxide compounds of silver in the oxidation of o-xylene and napthalene. Kinetika i Katlitz 4 963-968. 

Oxa method for naming ethers, 300, 400 Oxazole, 458, 460 Oxidation, tinthracene, 202 benzene, 201 napthalene, 201 phenanthiene, 202 Oxidation number, 21, 29 Oxidation-reduction, 33 Oxidative cleavage, 117 Oxo process, 307... 

Recently the large pore vanadium containing molecular sieve, V-NCL-1 with a pore size of 7 A, has been shown to be an active catalyst for the oxidation of larger molecules, such as napthalenes, 1,4-napthoquinones and phthalic anhydride (Scheme 22)[187]. The as synthesised form of V-NCL-1 contains atomically dispersed V4+ ions located in fiamework postions although not neccessarily in tetrahedral coordination. The vandium ions can be oxidised to the pentavalent state by calcination, as evidenced by ESR [157], with some... 

Scheme 22. Oxidation of napthalene over large pore V-NCL-1.

Benzo-quinone.—Benzoquinone, or more commonly, simply quinone, is the most common and important of the quinones derived from benzene. Other important quinones will be met with when we study derivatives of the more complex hydrocarbons napthalene and anthracene. Benzoquinone is the one we have used as our example in the above discussion and it is the para-di-keto benzene. It was first obtained by the oxidation of quinic acid, which in turn was obtained from quinine, hence its name. It may also be prepared by oxidizing... 

Coloration and absorption bands have been early noticed in the author s laboratory, when napthalene and anthracene vapor were adsorbed under high vacuum conditions on to a silica-alumina catalyst. They had been ascribed at that time to an oxidation of the adsorbed hydrocarbons by traces of oxygen in the adsorbent. Later study disproved this preliminary interpretation. Meanwhile several authors reported on the appearance of visible colorations and of an EPR spectrum, when anthracene and perylene were adsorbed from evacuated solutions on to a degassed silica-alumina catalyst (106-108). The EPR findings gave indication that adsorbed radicals were involved, similar to those found in strongly oxidizing acid solutions, where the anthracene or perylene cation radicals were expected to be formed (109). 

The difference between the action of oxidizing agents on the nitro derivative and the amino derivative is observed in the case of other compounds. Benzene derivatives which contain an amino group are readily decomposed by oxidizing agents, whereas rings which contain nitro groups are stable. The structure of napthalene is expressed by the formula,—... 

Fig. 6 Proposed catalytic oxidation cycle for conver.sion of napthalene-2-carbaldehyde to methyl naphthalene-2-carboxylate using a...

Liquid etchants can be used for chenucal modification or dissolving surface contamination. Etchants effectively treat irregularly shaped objects that are difficult to treat by other adhesion-promoting processes such as corona or flame treatment. A number of etching solutions and procedures have been developed for specific polymeric surfaces. The choice of the liquid etchant depends on the polymers. Polyolefins are usually treated by oxidizing acids such as chromic, sulfuric, nitric, or mixtures of these. Fluorocarbons are usually treated by sodium-napthalene etching solution. 

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