Benzene anodic oxidation

The anodic oxidation of organic substances is a complex multistep process. The question as to the depth of oxidation required (and sufficient) lias to be answered in each case. Where intermediate oxidation products pose no ecological risk, one can stop at incomplete oxidation. However, in the anodic oxidation of many aromatic substances, the corresponding quinones are formed in the first step, and these are more harmful than the original substances. Upon more profound oxidation, the benzene rings are broken and aliphatic substances are formed that are almost as harmless as carbon dioxide. 

It is well-known that the anodic trifluoroacetoxylation of benzene derivatives is a useful method for the preparation of phenol derivatives (Eq. 30). Schafer et al. have successfully achieved CH-functionalization of various hydrocarbons by anodic oxidation in 0.05 M Bu4NPF6/CH2Cl2 containing 20% TFA and 4% (CF3C0)20 as shown in Eqs 31 and 32 [75]. 

Anodic oxidations of hexathioalkyl benzene asterisk compounds were achieved at a Pt anode in AN. In particular, hexa-iso-propylthio-benzene afforded both the primary cation radical and the free radical obtained from the deprotonation (Eq. 10). 

The combination of anodic oxidation of benzene using the Ag(I)/Ag(II) mediator with cathodic oxidation of benzene using the Cu(I)/Cu(II) mediator in a single electrolytic cell produces p-benzoquinone selectively in both the anodic and the cathodic chambers [242]. Silver-mediator promoted electrooxidation of hydrocarbon has been attempted [243]. The kinetics of indirect oxidation of catechol and L-dopa with IrCl6 has been studied in polymer-coated glassy carbon [244]. 

Vinyl ether radical-cations also react in a radical substitution fashion with an adjacent electron rich benzene ring [59]. However the reaction products from simple examples such as 33 themselves readily undergo a further anodic oxidation... 

Reactions between aromatic hydrocarbon radicabcations and cyanide ions, with few exceptions, give low yields of nuclear substitution products [76], In some cases, better results have been obtained by anodic oxidation of the aromatic compound in an emulsion of aqueous sodium cyanide and dichloromethane with tetra-butylammonium hydrogen sulphate as a phase transfer agent [77, 78]. Methoxy-benzenes give exceptionally good yields from reactions in acetonitrile containing tetraethylammonium cyanide, sometimes with displacement of methoxide [79, 80]... 

Anodic oxidation of 1,2,3-trimethoxybenzene in acetone containing dilute sulphuric acid gives 2,6-dimethoxybenzoquinone but in contrast 1,2,4-trimethoxy-benzene affords the dehydrodimer 11 in good yield [82]. Dehydrodimerization becomes an important process in the oxidation of methoxybenzenes in dichlo-... 

Reactions of Ph" radicals (12h) formed at anodes yield styrene (30), biphenyl (31), p-terphenyl (32), insoluble hydrocarbon of high molecular weight and, in smaller amounts, benzene (33) as well as ethanol (19). 30 was the main product for substituted reagents 5q and 5r but for unsubstituted 5e only if the current efficiency, Teu was low. For higher Y i values 31 became the chief organic product. However, in contrast to aliphatic Grignard reagents, except methyl, the current efficiency was always much below 100%. In order to explain the above results the possibility of another route of anodic oxidation, different... 

Hydroquinone or Quinone Benzene Several Past pilot-plant Paired synthesis or anodic oxidation + chemical reduction... 

Fuchigami and coworkers and Yoshida and coworkers independently found that anodic oxidation of benzylsilanes in the presence of nucleophiles such as alcohols and carboxylic acids resulted in a selective cleavage of the C—Si bond and the oxygen nucleophiles were introduced exclusively into the benzylic position (equation 6)11-13. In the absence of nucleophiles, the benzylsilane itself plays a role of a nucleophile and benzyl(trimethylsilyl-methyl)benzene is formed (equation 7)11,12. 

In particular, (diacyloxyiodo)benzene such as phenyliodine(III) diacetate (PIDA) and phenyliodine(III) bis(trifluoroacetate) (PIFA) have received a great deal of attention due to their reactivities similar to those of heavy metal reagents or anodic oxidation, low toxicity, ready availability and easy handling. Accordingly, a variety of useful oxidation reactions using iodine(III) or iodine(V) reagents have been developed recently. A number of previous review articles and... 

Michael Faraday is best known for work in the 1820s and 1830s establishing that a moving magnetic field induces an electric potential. He built the first dynamo for electricity generation. He also discovered benzene, invented oxidation numbers, and popularized the terms electrode, anode, and cathode. The SI unit of electrical capacitance is named in his honor. 

The (difluoroiodo)arene reagents can be synthesized by anodic oxidation of4-substituted iodo-benzenes. l-(Difluoroiodo)-4-methoxyben/ene is used as a fluorinating agent for l.. -dithio-lanes without isolation and purification. The electrolytic solution is simply mixed with a solution of the dithiolane. The electrolytic cell is depicted in Figure 2. 

The cathodic hydrogenation and anodic oxidation of benzene have been investigated by DEMS at Au(lll) and Au(332) electrode surfaces electrodeposited with ultrathin Pd films. The use of submonolayer Pd films was to eliminate possible interferences by (sub-surface) hydrogen absorbed in crystalline or thick-film Pd. The Au(332) surface was selected because, at fairly low submonolayer coverages (e.g., 0.14 monolayer), Pd preferentially deposits on the step sites as the coverage is increased (e.g., 0.82 ML), the... 

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