Reactions of Alcohols Oxidation

Several examples have been reported of the use of palladium-mediated oxidation reactions of alcohols and alkyl halides. Palladium(II) acetate in the presence of iodobenzene converts primary and secondary alcohols into carbonyl compounds under solid-liquid two-phase conditions [20], However, other than there being no further oxidation to carboxylic acids, the procedure has little to commend it over other methods. It is relatively slow with reaction times in the order of 2 days needed to achieve yields of 55-100%. 

A remarkable number of palladium-catalyzed aerobic oxidation reactions of alcohols have been reported to date [15]. Unfortunately, although some progress has been made with heterogeneous Pd catalysts, such as Pd on activated carbon [16], Pd on pumice [17], Pd-hydrotalcite [18], Pd on Ti02 [19] and Pd/SBA-15 [20], most of these systems suffer from low catalytic activities and a limited substrate scope. 

The technique was used in four case studies including the replacement of dichloromethane as a solvent in oxidation reactions of alcohols, which is an important area of green chemistry. 2-Pentanone, other ketones and some esters were suggested as suitable replacement solvents. At this point, the programme was not able to assess the effects of non-organic solvents because of a lack of available data. However, this approach holds promise for reactions where a VOC could be replaced with a far less hazardous, less toxic or bio-sourced option. 

Table 5.3-7 Oxidation reactions of alcohols in ionic liquids. 

The high dispersion of the Pd clusters and the presence of single Pd sites in Pd-(Ni-Zn)/C and Pd-(Ni-Zn-P)/C have been suggested to be important factors in boosting the electrocatalytic performance of these materials. On the other hand, although independent CV experiments in KOH solution with Ni-Zn/C and Ni-Zn-P/C electrodes, prior and after alcohol addition, have excluded any direct role of the Ni support,the existence of a co-catalytic effect of Ni on the Pd-catalyzed oxidation reaction of alcohols cannot be disregarded. In fact, several researchers have reported that the co-presence of nickel or nickel oxide may have a... 

Intramolecular oxidative reactions of alcohols, phenols, and carboxylic acids have also been studied extensively. These reactions have been exploited for the s)mthesis of natural... 

In oxidation reactions of alcohols, identify the type of alcohol as 1°, 2°, or 3°.Tertiary alcohols remain unreactive. Secondary alcohols are oxidized to ketones. Primary alcohols are oxidized to aldehydes when PCC is used as the oxidizing agent, and to carboxylic acids when chromic acid is used as the oxidizing agent. 

This chapter also introduces the oxidation reactions of alcohols. These reactions involve addition reactions in their first steps. For example, in the oxidation of primary alcohols by CrOs, the first step is addition of the alcohol to the chromium-oxygen double bond (Figs. 16.67 and 16.68). 

It should be emphasized that the reaction scheme of Eq. (49) is unlikely if hydroperoxides are distributed homogeneously over the whole sample. Owing to restricted mobility below Tm, the oxidation products carmot diffuse away. Locally, hydroperoxides can reach sufficiently high concentrations for secondary reactions to occur at a significant rate. In a similar fashion, the formation of carboxylic acids, esters and y-lactones proceeds through a complex series of oxidation reactions of alcohols and ketones. 

Oxidation reactions of alcohols by lead(IV) acetate can be accelerated in the presence of pyridine. A kinetic study of this reac-... 

Yadav DKT, Bhanage BM (2013) Copper-catalyzed synthesis of nitriles by aerobic oxidative reaction of alcohols and ammonium formate. Eur J Org Chem 23 5106-5110... 

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