Anthraquinone toluene oxidation

Yellow needles from xylene, mp 226°, Sublimes. Absorption max Conrad-Billroth, Z. Physik. Chem. (Leipzig) 33B, 133 (1936). Insol in water slightly sol in alcohol, ether, cold benzene sol in hot benzene, hot toluene. Oxidation gives anthraquinone. 

The products of toluene oxidation, chiefly benzaldehyde, benzoic acid, maleic acid, and anthraquinone, are obtained in proportions that depend upon catalyst, temperature, oxygen ratio, and time of contact. High temr pieratures, mild catalysts, and short times of contact promote the formation... 

The performance of many metal-ion catalysts can be enhanced by doping with cesium compounds. This is a result both of the low ionization potential of cesium and its abiUty to stabilize high oxidation states of transition-metal oxo anions (50). Catalyst doping is one of the principal commercial uses of cesium. Cesium is a more powerflil oxidant than potassium, which it can replace. The amount of replacement is often a matter of economic benefit. Cesium-doped catalysts are used for the production of styrene monomer from ethyl benzene at metal oxide contacts or from toluene and methanol as Cs-exchanged zeofltes ethylene oxide ammonoxidation, acrolein (methacrolein) acryflc acid (methacrylic acid) methyl methacrylate monomer methanol phthahc anhydride anthraquinone various olefins chlorinations in low pressure ammonia synthesis and in the conversion of SO2 to SO in sulfuric acid production. 

Has been purified by co-distillation with ethylene glycol (boils at 197.5°), from which it can be recovered by additn of water, followed by crysm from 95% EtOH, benzene, toluene, a mixture of benzene/xylene (4 1), or EtjO. It has also been chromatographed on alumina with pet ether in a dark room (to avoid photo-oxidation of adsorbed anthracene to anthraquinone). Other purification methods include sublimation in a N2 atmosphere (in some cases after refluxing with sodium), and recrystd from toluene [Gorman et al. J Am Chem Soc 107 4404 1985]. 

Also important is the choice of a suitable redox system for the indirect electroreaction of particular substrates. For instance, toluene can be oxidized with Mn(III) or Ce(IV) to benzaldehyde, whilst with Cr(VI) benzoic acid is obtained. On the other hand, anthraquinone is commercially prepared from anthracene by employing chromic acid oxidation. 

Methyl anthraquinone has been obtained by the oxidation of /3-methyl anthracene by several investigators 1 and material of the same origin, obtained by the benzene-extraction of crude commercial anthraquinone,2 has been fully described. As regards the synthesis from phthalic anhydride and toluene, both the preparation and properties of />-toluyl-o-benzoic acid 3 and the complete synthesis 4 have been the subject of several papers. This acid has also been prepared from o-carbomethoxy benzoyl chloride and toluene.5 The phthalic anhydride synthesis of anthraquinone derivatives in general has received considerable attention. An account of this work, together with extensive references, is given by Barnett.6... 

The selective oxidation of toluene has been studied over a number of catalysts based on metal oxides, with the U/Mo oxide system being one of the most achve and selective[50, 51]. The main products in the oxidation of toluene, excluding the non-oxidative coupling products, were benzaldehyde, benzoic acid, maleic anhydride, benzene, benzoquinone, CO and CO2. Under the same reachon condihons toluene may also yield coupling products such as phthalic anhydride, methyldi-phenylmethane, benzophenone, diphenylethanone and anthraquinone, as shown by Zhu and coworkers [51]. A range of different uranium-based oxides were tested [51] and the results obtained are shown in Table 13.4. 

V. Catalysts.—Electrolytic oxidation reactions are often facilitated by the presence of catalysts capable of existing in two valence stages examples of such oxygen carriers are cerium, chromium, manganese and vanadium ions. Their action is probably similar to that previously described for hydrogen carriers. These catalysts have been used to facilitate the oxidation of toluene to benzaldehyde or benzoic acid, of toluene sulfonamide to saccharin, and of anthracene to anthraquinone. 

The relative proportions in which the products, chiefly benzaldehyde, benzoic acid, and anthraquinone, are obtained depends in a large measure on the temperatures to which the reaction mixture of toluene vapor and air is subjected. High temperatures, together with rapid rates of flow as well as high temperatures and mild catalysts, are conducive to bai-zaldehyde formation. With vanadium pentoxide catalysts oxidation of... 

The reactions may also be accelerated by the addition of organic compounds to the hydrocarbon. The oxidation of toluene under the action of light is accelerated by the addition of phenanthraquinone, which is itself attacked in the reaction, however, to form diphenic acid.110 Anthraquinone and its halogen-substitution products are of greater effect.120... 

Electra-organic synthesis Chlorination of substituted naphthalenes. Toluene and aromatic hydrocarbon oxidation using Ce as a redoxmediator. Anthracene oxidation to anthraquinone using Mn as the redox medi ator. Forsyth et al. (1987) Pletcher Valdez (1988a,b) Chou etal. (1992)... 

Gas-liquid reactions are used in several industrial processes. In the synthesis of chemical compounds, gas-liquid reactions are used in, for example, the oxidation of hydrocarbons. For a synthesis reaction, it is typical that one organic compound is transformed into another organic compoimd in the presence of a homogeneous catalyst. Typical reactions are, for example, chlorination of aromatic compounds in the production of chlorinated hydrocarbons, chlorination of carboxylic acids (mainly acetic acid), and oxidation of toluene and xylene in the production of benzoic acid and phthalic acid. In the production of hydrogen peroxide (H2O2), an oxidation process can also be used, namely oxidation of anthraquinole to anthraquinone. 

In their study utiHzing vanadium oxide catalysts in the 1950s, Mars and van Kre-velen investigated the oxidation ofbenzene to benzoquinone, maleic anhydride, CO2, CO, and H2O, toluene to benzaldehyde and benzoic acid, naphthalene to naphthoquinone and phthalic anhydride, and anthracene to anthraquinone and phthalic anhydride. 

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