Benzene degradation, oxidative

Reactions with Organic Compounds. Tetrafluoroethylene and OF2 react spontaneously to form C2F and COF2. Ethylene and OF2 may react explosively, but under controlled conditions monofluoroethane and 1,2-difluoroethane can be recovered (33). Benzene is oxidized to quinone and hydroquinone by OF2. Methanol and ethanol are oxidized at room temperature (4). Organic amines are extensively degraded by OF2 at room temperature, but primary aHphatic amines in a fluorocarbon solvent at —42°C are smoothly oxidized to the corresponding nitroso compounds (34). 

The Hammett correlation for nitrobenzenes is almost identical to the correlation at pH 9 therefore, the degradation of substituted benzenes at pH 3 can also be described by the same hole oxidation mechanism. Figure 9.21 demonstrates the oxidation of nitrobenzene by positive hole. At pH 3, substituted benzenes are oxidized by the formation of a positive hole. An electron transfer from nitrobenzene to Ti02 creates this positive hole. 

Degradative oxidation of unsaturated carboxylic acids leads either to aldehydes or to dicarboxylic acids. In the presence of sodium carbonate and benzene, o-nitrocinnamic acid is oxidized with potassium permanganate at 10 °C to o-nitrobenzaldehyde in 64% isolated yield [842]. 

Weiner, J.M. and D.R. Lovley. 1998. Anaerobic benzene degradation in petroleum-contaminated aquifer sediments after inoculation with a benzene-oxidizing enrichment. Appl. Environ. Microbiol. 64 775-778. 

Ozone can be used to completely oxidize low concentrations of organics in aqueous streams or partially degrade compounds that are refractory or difficult to treat by other methods. Compounds that can be treated with ozone include alkanes, alcohols, ketones, aldehydes, phenols, benzene and its derivatives, and cyanide. Ozone readHy oxidizes cyanide to cyanate, however, further oxidation of the cyanate by ozone proceeds rather slowly and may require other oxidation treatment like alkaline chlorination to complete the degradation process. 

Most of these furan polycondensates are more sensitive to thermal and oxidative degradation than their benzene counterparts. Particularly affected are the polyesters obtained from 2,5 -fci sfhydroxymethyl) furan indicating that one of the vulnerable groups must be the -Fu—CH2—0-, and not the -Fu—CO—O-, since polycondensates obtained from 2,5-dicarboxylic acid are more stable, as expected from the... 

In a classical study, it was shown that during bacterial oxidation of benzene to catechol both atoms of oxygen came from 62 (Gibson et al. 1970). This initiated the appreciation of the role of dioxygenases in the degradation of aromatic xenobiotics, and many examples are given in Chapter 8, Parts 1 and 2. 

Gibson DT, JR Koch, RE Kallio (1968) Oxidative degradation of aromatic hydrocarbons. I. Enzymatic formation of catechol from benzene. Biochemistry 9 2653-2662. 

The first successful transformation of protoberberines to benzo[c]-phenanthridines was reported by Onda et al. (122,123). Irradiation of the enamines 200 and 195, the Hofmann degradation products of the corresponding protoberberines, in benzene afforded the initial photoproducts 201, which immediately rearranged to the tetrahydrobenzo[c]phenanthridines 202 in 70% yield (Scheme 37). Dehydrogenation of 202 afforded dihydro-chelerythrine (203) and dihydrosanguinarine (204), which were further oxidized with dichlorodicyanobenzoquinone (DDQ) to yield chelerythrine (205) and sanguinarine (206), respectively. 

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