Air oxidation, catalytic

Of little use commercially except as a route to anthraquinone. For this purpose it is oxidized with acid potassium dichromate solution, or better, by a catalytic air oxidation at 180-280 C, using vanadates or other metal oxide catalysts. 

Raw Materials. Eor the first decade of PET manufacture, only DMT could be made sufficiently pure to produce high molecular weight PET. DMT is made by the catalytic air oxidation of -xylene to cmde TA, esterification with methanol, and purification by crystallization and distillation. After about 1965, processes to purify cmde TA by hydrogenation and crystallization became commercial (52) (see Phthalic ACID AND OTHER... 

In several important cases, new synthetic strategies have been developed into new production schemes. An outstanding example of this is the production of an entire family of terpene derivatives from a-pinene (29), the major component of most turpentines, via linalool (3) (12). Many of these materials had been produced from P-pinene, a lesser component of turpentine, via pyrolysis to myrcene and further chemical processing. The newer method offers greater manufacturing dexibiUty and better economics, and is environmentally friendly in that catalytic air oxidation is used to introduce functionality. 

Industrial production of sodium nitrite is by absorption of nitrogen oxides (NO ) into aqueous sodium carbonate or sodium hydroxide. NO gases originate from catalytic air oxidation of anhydrous ammonia, a practice common to nitric acid plants ... 

Future Methods. A by-product stream containing 60—80% PEA can be obtained from the catalytic air oxidation of ethylbenzene [100-41-4] (100). Perfumery-grade material can be isolated from this stream by complexing the PEA with a metal haUde (such as CaCl2), separation of the adduct, and thermal decomposition followed by distillation. 

Allied-Signal Process. Cyclohexanone [108-94-1] is produced in 98% yield at 95% conversion by liquid-phase catal57tic hydrogenation of phenol. Hydroxylamine sulfate is produced in aqueous solution by the conventional Raschig process, wherein NO from the catalytic air oxidation of ammonia is absorbed in ammonium carbonate solution as ammonium nitrite (eq. 1). The latter is reduced with sulfur dioxide to hydroxylamine disulfonate (eq. 2), which is hydrolyzed to acidic hydroxylamine sulfate solution (eq. 3). 

BASF. In the Badische process, cyclohexanone is produced by Hquid-phase catalytic air oxidation of cyclohexane to KA oil, which is a mixture of cyclohexanone and cyclohexanol, and is followed by vapor-phase catalytic dehydrogenation of the cyclohexanol in the mixture. Overall yields range from 75% at 10% cyclohexane conversion to 80% at 5% cyclohexane conversion. 

Snia Viscosa. Catalytic air oxidation of toluene gives benzoic acid (qv) in ca 90% yield. The benzoic acid is hydrogenated over a palladium catalyst to cyclohexanecarboxyhc acid [98-89-5]. This is converted directiy to cmde caprolactam by nitrosation with nitrosylsulfuric acid, which is produced by conventional absorption of NO in oleum. Normally, the reaction mass is neutralized with ammonia to form 4 kg ammonium sulfate per kilogram of caprolactam (16). In a no-sulfate version of the process, the reaction mass is diluted with water and is extracted with an alkylphenol solvent. The aqueous phase is decomposed by thermal means for recovery of sulfur dioxide, which is recycled (17). The basic process chemistry is as follows ... 

Cyclohexanol. This alcohol is produced commercially by the catalytic air oxidation of cyclohexane or the catalytic hydrogenation of phenol. 

For many years the catalytic air oxidation of benzene was the main source of maleic anhydride. Obviously, two carbons from each ring are wasted as carbon dioxide in this process. Although some is still made that way, most modem maleic anhydride plants are based on butane oxidation. Because butane is forecast to be plentiful and low-cost, new routes to four-carbon chemicals from maleic anhydride are under active development. 

Ethylene is to be converted by catalytic air oxidation to ethylene oxide. The air and ethylene are mixed in the ratio 10 1 by volume. This mixture is combined with a recycle stream and the two streams are fed to the reactor. Of the ethylene entering the reactor, 40% is converted to ethylene oxide, 20% is converted to carbon dioxide and water, and the rest does not react. The exit gases from the reactor are treated to remove substantially all of the ethylene oxide and water, and the residue recycled. Purging of the recycle is required to avoid accumulation of carbon dioxide and hence maintain a constant feed to the reactor. Calculate the ratio of purge to recycle if not more than 8% of the ethylene fed is lost in the purge. What will be the composition of the corresponding reactor feed gas ... 

Anthraquinone itself is traditionally available from the anthracene of coal tar by oxidation, often with chromic acid or nitric acid a more modern alternative method is that of air oxidation using vanadium(V) oxide as catalyst. Anthraquinone is also produced in the reaction of benzene with benzene-1,2-dicarboxylic anhydride (6.4 phthalic anhydride) using a Lewis acid catalyst, typically aluminium chloride. This Friedel-Crafts acylation gives o-benzoylbenzoic acid (6.5) which undergoes cyclodehydration when heated in concentrated sulphuric acid (Scheme 6.2). Phthalic anhydride is readily available from naphthalene or from 1,2-dimethylbenzene (o-xylene) by catalytic air oxidation. 

Acetic acid, the most important carboxylic acid, can be prepared by catalytic air oxidation of acetaldehyde. 

Ethyl alcohol has been made by the hydration of ethylene (9) since 1930. Like isopropyl alcohol, part of the output is used as a solvent, but most is converted to other oxygenated chemicals. Its most important raw material use is conversion to acetaldehyde by catalytic air oxidation. Acetaldehyde, in turn, is the raw material source of acetic acid, acetic anhydride, pentaerythritol, synthetic n-butyl alcohol (via aldol condensation), butyraldehyde, and other products. Butyraldehyde is the source of butyric acid, polyvinyl butyral resin, and 2-ethylhexanol (octyl alcohol). The last-named eight-carbon alcohol is based on the aldol condensation of butyraldehyde and is used to make the important plasticizer di-2-ethylhexyl phthalate. A few examples of the important reactions of acetaldehyde are as follows ... 

Acrolein and Acrylic Acid. Acrolein and acrylic acid are manufactured by the direct catalytic air oxidation of propylene. In a related process called ammoxida-tion, heterogeneous oxidation of propylene by oxygen in the presence of ammonia yields acrylonitrile (see Section 9.5.3). Similar catalysts based mainly on metal oxides of Mo and Sb are used in all three transformations. A wide array of single-phase systems such as bismuth molybdate or uranyl antimonate and multicomponent catalysts, such as iron oxide-antimony oxide or bismuth oxide-molybdenum oxide with other metal ions (Ce, Co, Ni), may be employed.939 The first commercial process to produce acrolein through the oxidation of propylene, however, was developed by Shell applying cuprous oxide on Si-C catalyst in the presence of I2 promoter. 

Compns of 91/9 RDX/waxes were furnished by the National Defense Research Committee to PicArsn for evaluation (Ref 13). Results of the investigation showed that the 90/10 Stream 2 (petroleum wax)/Alox 600 (a catalytic air oxidation product from petroleum) is a suitable substitute for beeswax for use in desensitizing RDX so as to make it suitable for use as a shell filler. Other waxes investigated and found acceptable (Ref 23) for use in conjunction with 10% Alox 600 include ... 

Future methods of production include catalytic air oxidation and... 

Anodic oxidation of alkylpyridines to pyridinecarboxylic acids is an old but viable synthetic procedure, usually giving the desired product in reasonable yield. In contrast to catalytic air oxidation, which works best for making... 

Since aldehydes can generally be converted to the corresponding carboxylic acids in very good yields and in a simple manner by catalytic air oxidation, electrochemical syntheses are not of much interest to the chemical industry. The controlled electrochemical oxidation of glyoxal to glyoxylic acid is an exception 279 280> ... 

Anionic organic complexes of Mo have been immobilized on LDHs. For example, a Mo(VI)02 complex containing 2-mercapto-2,2-diphenyl-ethanoate ligands (14) was supported on ZnAl LDH and used for the catalytic air oxidation of thiols (269-271). Although the homogeneous dioxoMo complex has some catalytic activity, it is rapidly deactivated as a result of the formation of dimers. By intercalation of the complex in an LDH structure, dimerization could be avoided, resulting in improved longevity. 

Catalytic Air Oxidation of Propylene to Acrolein Modeling Based on Data from an Industrial Fixed-Bed Reactor... 

SCT can be converted into highly aromatic pitches by physical, thermal and chemical processes such as vacuum or steam stripping, thermal or catalytic oxidative-polymerization at 229-260°C, or by a thermal process at 370-450°C at atmospheric nitrogen or hydrogen pressure. The physical or chemical characteristics of the pitches produced from SCT depend on the type of process and conditions used. Table II gives the characteristics of SCT pitches produced by distillation, catalytic air-oxidation and thermal process. 

A more economic process has been commercialized. In one version, the hydroperoxide is produced by catalytic air-oxidation of a hydrocarbon such as ethylbenzene (see top of page). Reaction of this hydroperoxide with propylene yields propylene oxide as a co-product. 

Thiosulfate solutions are generally prepared from sodium thiosulfate penta-hydrate, NajSjOa SHjO, which under ordinary conditions is not a primary standard. The solutions should be prepared from water free of heavy-metal impurities to avoid catalytic air oxidation. Ordinary air oxidation is negligible in rate and proceeds through the slow decomposition of thiosulfate to sulfite, which is rapidly air-oxidized to sulfate. Catalyzed air oxidation, on the other hand, proceeds through the reduction of metals such as copper(II) or iron(III), present as thiosulfate complexes, followed by air oxidation of the lower oxidation state ... 

Noronha, G., Henry, P. M. Heterogenized polymetallic catalysts Part III. Catalytic air oxidation of alcohols by Pd(ll) complexed to a polyphenylene polymer containing P-di- and tri-ketone surface ligands. J. Mol. Catal. A Chemical 1997, 120, 75-87. 

Derivation Trimerization of acetaldehyde and catalytic air oxidation of the resulting hexadienal. Found in berries of mountain ash. 

Selective oxidation of a secondary allylic hydroxyl group. D-Glucol (1) is selectively oxidized to the enone (2) in 60-80% yield by the reagent.3 This oxidation had been effected previously in 1.5% yield by catalytic air oxidation.4... 

The second-step oxidation is normally by means of nitric acid, but catalytic air oxidation results in good yields of adipic acid. In recent practice, the refined first-step product of cyclohexane oxidation freed of unconverted hydrocarbon and a 50-60 per cent nitric acid solution containing copper-vanadium catalyst are separately and continuously fed to a jacketed reaction vessel at a ratio such that weight ratio of 100 per cent nitric acid to organic feed is between 2.5 and 6. The reaction mixture is rapidly recirculated through a tubular reactor at 60-80°C, and fresh feed is admitted to give about 5 min time of contact. Yields are improved by reheating the continuously withdrawn effluent stream to 95-100°C for a... 

A Cr(VI) sulfoxide complex has been postulated after interaction of [CrOjtClj] with MejSO (385), but the complex was uncharacterized as it was excessively unstable. It was observed that hydrolysis of the product led to the formation of dimethyl sulfone. The action of hydrogen peroxide on mesityl ferrocencyl sulfide in basic media yields both mesityl ferrocenyl sulfoxide (21%) and the corresponding sulfone (62%) via a reaction similar to the Smiles rearrangement (165). Catalytic air oxidation of sulfoxides by rhodium and iridium complexes has been observed. Rhodium(III) and iridium(III) chlorides are catalyst percursors for this reaction, but ruthenium(III), osmium(III), and palladium(II) chlorides are not (273). The metal complex and sulfoxide are dissolved in hot propan-2-ol/water (9 1) and the solution purged with air to achieve oxidation. The metal is recovered as a noncrystalline, but still catalytically active, material after reaction (272). The most active precursor was [IrHClj(S-Me2SO)3], and it was observed that alkyl sulfoxides oxidize more readily than aryl sulfoxides, while thioethers are not oxidized as complex formation occurs. 

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