Gulonic acid oxidation, chemical

In the synthesis of vitamin C, the oxidation of diacetone L-sorbose to diacetone 2-keto-L-gulonic acid proceeds at an Ni-anode in the presence of hydroxide. Under these conditions, the nickel hydroxide surface is anodically transformed to NiOOH, the nickel peroxide, which acts as chemical oxidant via hydrogen atom abstraction. Thus, a chemically modified redox-active electrode acts as a heterogeneous redox catalyst [13] ... 

A nickel anode is in alkaline solution protected against corrosion by a layer of nickel oxides. oxide (NiOOH) is capable of oxidizing a number of functional groups primary alcohols may be oxidized to carboxylic acids [158-161], which is of interest for the technical production of an intermediate for vitamin C production [162]. NiOOH chemically oxidizes the substrate and is regenerated electrochemically a large anode surface, which is realized in the Swiss-roll cell (Chap. 31), is thus advantageous. NiOOH electrodes in form of nickel foam electrodes has been found to be useful for the oxidation of diacetone L-sorbose to diacetone 2-keto-L-gulonic acid in the vitamin C synthesis [163]. 

The chemical steps in the conversion of sorbose to ascorbic acid involve the preparation of the diacetone derivative, which then is oxidized the acetone groups are removed, and the resultant 2-keto-L-gulonic acid is isomerized to the enediol with ring closure. 

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