2-Ketoses catalytic oxidation

Much is known about the catalytic mechanism of triose phosphate isomerase. TIM catalyzes the transfer of a hydrogen atom from carbon 1 to carbon 2 in converting dihydroxyacetone phosphate into glyceraldehyde 3-phosphate, an intramolecular oxidation-reduction. This isomerization of a ketose into an aldose proceeds through an enediol intermediate (Figure 16.6). 

Vapor phase oxidation processes prevail over liquid phase processes, although the latter are sometimes used inlarge-scale chemical production when the products (i) can be easily recovered from the reaction medium, as interephthalic acid production, for example (ii) are thermally unstable (i.e., in the production of hydroperoxides and carboxylic acids, except for P-unsaturated compounds) and (iii) are very reactive at high temperature (i.e., epoxides, aldehydes and ketoses, with the exception of ethene oxide and formaldehyde). Liquid-phase oxidation is also preferred in fine chemicals production, although most processes are still non-catalytic. 

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