Types of oxidative reactions

Dehydrogenation is illustrated in the tran ormation of a primary alcohd to an aldehyde  

An atom of oxygen may be iirtroduced into a molecule, as is illustrated by the oxidation of an aldehyde to an acid  

Dehydrogenation may also be accompanied by molecular condensation, as is the case when two molecules of benzene form diphenyl or two molecules of toluene form stilbene or when methylanthraquinone is converted to anthracene yellow C. 

Dehydrogenation, oxygen introduction, and destnu on of carbon linkages may all occur in the same process of oxidation, e.g., in the oxidation of naphthalene to phthalic anhydride  

Oxidation may be accomplished indirectly through the use of inter mediate reactions  

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Oxidation. There are 10 types of oxidative reactions in use industriaHy (80). Safe reactions depend on limiting the concentration of oxidi2ing agents or oxidants, or on low temperature. The foUowing should be used with extreme caution salts of permanganic acid hypochlorous acid and salts sodium... 

Types of Oxidation Reactions invoived in Enzymatic Drug Metaboiism... 

Oxidation of Stable Systems not Involving a Permanent Change in the Oxidation State of the Central Atom. The two possible overall mechanisms for this type of oxidation reaction may be formulated as follows ... 

Let us look at the major types of oxidation reaction catalyzed by the cytochromes P-450 system. 

Combustion reactions are one type of oxidation reaction. In the past, the term oxidation was used to mean the combination of an element with oxygen to make an oxide. For example, when methane (CH4) burns in oxygen, it produces oxides of carbon and hydrogen. 

Another type of oxidation reaction occurs when iron is exposed to the oxygen in the air. Rust, or iron(III) oxide (Fe203), is produced. This type of oxidation occurs over a long period of time. The iron does not burn, it just rusts. 

Recently, an application of this type of oxidation reaction towards the synthesis of 2-halopyridine N-oxide derivatives, which are intermediates of pyrithione antimicrobial agents, has been patented by a Korean company [146]. It is reported that iron (III) oxide (10-100 mol%) provides the best results among all iron catalysts tested, such as FeCl3, Fe2(S04)3 and Fe(C104)3. 

A final type of oxidation reaction associated with the loss of hydrogen atoms is seen in the oxidative dimerisation of phenols. In general, the oxidation of phenols, in either the presence or absence of metal ions, is not a clean process, and many products, derived from... 

Figure 9-26. The various types of oxidation reaction catalysed by metalloenzymes. The conversion of a phenol to a 1,2-dihydroxybenzene and the ring opening oxidation both involve oxygen atom transfer to the substrate, whilst the oxidation of a 1,2-diol to a 1,2-quinone is of the type discussed earlier in this chapter.

Two types of oxidation reactions are of interest in ceramics oxidation of metals and oxidation of sulfides. The oxidation of sulphides is a common extractive metallui cal process, generating an oxide ceramic powder. The oxide product is usually an intermediate product on the way to metal production but if sufficiently pure it can be used directly as a ceramic powder. A common example is the roasting of zinc sulphide to form zinc oxide,... 

These reactions are strongly exothermic, which is typical of these types of oxidation reactions. This means that the heat produced by the reaction will heat up the particle and further increase the reaction rate. The equilibrium constant for the oxidation of zinc sulphide is given by... 

It is interesting to note that few examples of propaigylic oxidation were found for either type of oxidation reaction. 

Aldoses contain 1° and 2° alcohols and an aldehyde, all of which are oxidizable functional groups. Two different types of oxidation reactions are particularly useful—oxidation of the aldehyde to a carboxylic acid (an aldonic acid) and oxidation of both the aldehyde and the 1 ° alcohol to a diacid (an aldaric acid). 

Type of oxidation reaction Cofactor involved Example of enzyme or protein... 

The investigations of Weiss and Downs, while dealing with all of the above types of oxidation reactions, concentrated much more specifically upon the oxidation of benzene itself in the vapor phase. This work was extended over a considerable period of time and was crowned by the actual production of maleic and fumaric acids on a commercial scale. The different phases of these investigations have been marked from time to time by the appearance of various American and foreign patents. However, the information which has been made public in this way has not been further supplemented by as detailed an account of the general method used by these investigators in their approach to the specific problem of the oxidation of benzene as would be desirable." In general, it may be said that the products which have been obtained by the oxidation of benzene under various conditions consist of phenol, dipheml, qninone. and maleic acid. 

The Mn =0 entity is a very powerful oxidant able to mediate two different types of oxidative reactions transfer of an oxygen atom on a substrate (mimic of cytochrome P450, Fig. 21A) or electron abstraction (mimic of peroxidase. Fig. 21B). It is formally written Mn =0 since it corresponds to a two-electron oxidation with respect to the initial Mn complex. However,... 

What are oxidation reactions List different types of oxidation reactions involved in the metabolism/degradation of toxic organisms. 

In the meantime, many other types of oxidation reactions catalyzed by Pd have also been discovered and developed. These other Pd-catalyzed oxidation reactions are discussed in Part VIII. For some practical reasons, however, a few additional oxidation reactions involving C—C bond formation are discussed in earlier sections, such as Sects. m.2.20, VI.4.4, and VI.7. 

Cytochrome P450 enzymes perform three general types of oxidative reactions ... 

In addition to various Pd-catalyzed or -promoted oxidation reactions discussed in earlier parts, for example, Part V, and the preceding sections in this part, there are many other types of oxidation reactions. Some may be related to those discussed earlier. And yet, they display some notably different features. In this section, several different types of snch oxidation reactions are discussed in no particular order. Moreover, the following discussion is by no means exhaustive, and it is very likely that many additional types of oxidation reactions, which do not belong to any group of oxidation reactions discussed in this Handbook, will be discovered in the future ... 

Oxidation reactions of the fatty acid hydrocarbon chains are common to free fatty acids and their esters, such as triacylglycerols. Carboxyl groups of free fatty acids, however, accelerate the decomposition of fatty acid hydroperoxides and can react with some oxidation products. In foods, the following types of oxidation reactions of lipids may occur ... 

Ri = H) with base and nonactivated Mn02 in ethanol afforded the corresponding ethyl esters. This type of oxidative reaction could be also achieved in THF with different nucleophiles, such as alcohol, water, thiol, and amine, to give the corresponding ester, carboxylic acid, thioester, and amide, respectively (scheme-36) (Chikashita et ah 1991). Riemer and Liebscher (1993) have described the synthesis of pyrimido[2,l-fc]benzoxazolium, pyrimido[2,l-fc]benzothiazolium salt (134) by the reaction of 3-isothiocyanato-2-propeniminium salts with 2-aminothiophenol followed by cyclization using methyl iodide by a new condensation reaction (Riemer Liebscher 1993). 

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