Acidic solvents hydrocarbon oxidation

Butane-Naphtha Catalytic Liquid-Phase Oxidation. Direct Hquid-phase oxidation ofbutane and/or naphtha [8030-30-6] was once the most favored worldwide route to acetic acid because of the low cost of these hydrocarbons. Butane [106-97-8] in the presence of metallic ions, eg, cobalt, chromium, or manganese, undergoes simple air oxidation in acetic acid solvent (48). The peroxidic intermediates are decomposed by high temperature, by mechanical agitation, and by action of the metallic catalysts, to form acetic acid and a comparatively small suite of other compounds (49). Ethyl acetate and butanone are produced, and the process can be altered to provide larger quantities of these valuable materials. Ethanol is thought to be an important intermediate (50) acetone forms through a minor pathway from isobutane present in the hydrocarbon feed. Formic acid, propionic acid, and minor quantities of butyric acid are also formed. 

Cobalt bromide is used as a catalyst in the technology of production of arylcarboxylic acids by the oxidation of methylaromatic hydrocarbons (toluene, p-xylene, o-xylene, polymethyl-benzenes). A cobalt bromide catalyst is a mixture of cobaltous and bromide salts in the presence of which hydrocarbons are oxidized with dioxygen. Acetic acid or a mixture of carboxylic acids serves as the solvent. The catalyst was discovered as early as in the 1950s, and the mechanism of catalysis was studied by many researchers [195-214],... 

Chemical resistance is generally good up to 60°C but polyethylenes are attacked by oxidizing acids, chlorinated solvents, certain oxidants, aromatic hydrocarbons. 

Suitable grades are usable in contact with food and are used for food packaging. Chemical resistance is generally good but polymethylpentenes are attacked by oxidizing acids, chlorinated solvents, certain oxidants and aromatic hydrocarbons. Resistance to aliphatic hydrocarbons, ketones, gasoline and kerosene is limited. 

The chemical resistance is generally inferior to that of comparable polyethylenes and decreases when VA rises. EVAs are attacked by concentrated strong acids, halogens, oxidizing acids, chlorinated solvents, certain oxidants, aliphatic and aromatic hydrocarbons, alcohols, ketones, esters, and some others. 

Materials. Chemically pure solvents and reagent grade ceric ammonium nitrate were used as received. Cumene hydroperoxide was purified via the sodium salt. Lucidol tert-butyl hydroperoxide was purified by low temperature crystallization. Tetralin hydroperoxide, cyclohexenyl hydroperoxide, and 2-phenylbutyl-2-hydroperoxide were prepared by hydrocarbon oxidation and purified by the usual means. 1,1-Diphenyl-ethyl hydroperoxide and triphenylmethyl hydroperoxide were prepared from the alcohols by the acid-catalyzed reaction with hydrogen peroxide (10). 

The autoxidation of hydrocarbons catalyzed by cobalt salts of carboxylic acid and bromide ions was kinetically studied. The rate of hydrocarbon oxidation with secondary hydrogen is exactly first order with respect to both hydrocarbon and cobalt concentration. For toluene the rate is second order with respect to cobalt and first order with respect to hydrocarbon concentration, but it is independent of hydrocarbon concentration for a long time during the oxidation. The oxidation rate increases as the carbon number of fatty acid solvent as well as of cobalt anion salt are decreased. It was suggested that the cobalt salt not only initiates the oxidation by decomposing hydroperoxide but also is responsible for the propagation step in the presence of bromide ion. 

The high oxidation potentials of alkanes, however, make it difficult to carry out the oxidation in solvents such as acetonitrile since the first intermediates generated in these oxidations are carbonium ions, as illustrated by equations (4) and (S), Their stabilization with strongly acidic solvents like anhydrous fluorosulfonic acid often lowers the oxidation potentials of these hydrocarbons. ... 

It will be apparent from Table 3 that, apart from the use of tetrafluoroborates and hexafluorophosphates, extended anodic limits can be obtained at low temperatures [212] or by the use of acidic solvents such as CF3COOH [81,211,216], FSO3H [186,217-221], HF [222], and CF3SO3H (without supporting electrolyte) [213]. In addition to the electrolyte systems included in the tables, hydrocarbon oxidation has been realized in nitromethane. 

Secondary alcohols give the respective ketones as products, regardless of the reaction conditions. Primary alcohols, however, can produce either aldehydes or carboxylic acids. Commonly, these oxidations are run in basic aqueous media. Under these conditions, the aldehydes that are formed initially react with the water to form a hydrate and this is oxidized further to the acid. Aldehydes, particularly aryl aldehydes, are the primary product only when the reaction is run in a neutral, preferably non-aqueous, medium such as a hydrocarbon solvent and usually with controlled oxygen uptake. 3,62... 

Tervalent phosphorus acid derivatives are normally liquids or low-melting solids which can be purified by distillation, or sometimes by recrystallization from a non-polar solvent. Most are oxidized in contact with the atmosphere, and many are easily hydrolyzed, so they must be kept under an inert atmosphere (N2 or Ar) during all manipulations. Flasks should be predried and solvents dried and deoxygenated before use. Tervalent phosphorus acid derivatives are, with few exceptions, thermally stable and can be kept indefinitely in ampoules under an inert gas (many halophosphines dissolve stopcock grease and should not be kept in stoppered flasks for prolonged periods). Inert solvents are hydrocarbons, ethers and, for most compounds, dichloromethane, ethyl acetate and tertiary amines. Aminophosphines react vigorously with tetrachloromethane and slowly with trichloromethane, and most tervalent phosphorus acid derivatives are oxidized by dimethyl sulphoxide and react with alcohols. 

Experimentally, it is uniformly observed that an aromatic hydrocarbon will suffer deprotonation from the benzylic position when irradiated in the presence of an SET sensitizer provided that (1) the sensitizer is a strong enough acceptor in the excited state to cause electron transfer from the substrate (2) the reaction is carried out in a polar solvent which does not interfere which any step of the process (acetonitrile is routinely used, but dimethylsulfoxide, which is competitively oxidized is not suitable the role of nucleophilic or acidic solvents will be discussed later) and (3) the BDE of the radical cation, evaluated as above, is negative or only slightly positive and there are no competing fragmentations with a sufficiently low BDE(RX ), with X sH (see Section 3.2). 

Reaction of cyanuric chloride with amines to give reactive dyes 2. Sulfonation and nitration of naphthalene at low temperatures 3. Reaction between terephthalic acid and ethylene oxide in a solvent in the presence of dissolved catalysts 4. Manufacture of diisocyanate by reaction between phosgene and hydrochlorides of amines 5. Alkaline hydrolysis of solid esters such as di-/3-chloroelhyl oxalate and nitrobenzoic acid esters Venkatraman (1972) Groggins (1958) Hydrocarbon Proc. Petrol. Refiner (1971) Bhatia et al. (1976) Sharma and Sharma (1969, I970a,b)... 

---