Carbohydrates selective catalytic oxidation

Heyns, K., and Paulsen, H., Selective Catalytic Oxidation of Carbohydrates, Employing Platinum Catalysts, 17, 169-221... 

K. Heyns and H. Paulsen, Selective catalytic oxidation of carbohydrates employing Pt catalysts, Adv. Carbohydr. Chem., 17 (1962) 169-221. 

SELECTIVE CATALYTIC OXIDATION OF CARBOHYDRATES, EMPLOYING PLATINUM CATALYSTS... 

As for hydrogenation, heterogeneous catalytic oxidation of carbohydrates was essentially performed in the presence of carbon-supported metal catalysts, namely Pt, Pd or Bi-doped Pd.[57] Oxidation of glucose into gluconic acid, the worldwide production of which is around 60000 tons year 1,[52] is used in the food and pharmaceutical industry, and is produced today by enzymatic oxidation of D-glucose with a selectivity in gluconic acid close to 100%. 

Most of these liquid phase catalytic oxidations have been used for the selective oxidation of carbohydrates. In the oxidation of a sugar such as glucose, four basic types of selective oxidation are possible. ... 

One important application is in the field of carbohydrate transformations, the catalytic oxidation of D-glucose to D-gluconic acid represents an economically competitive route with respect to biochemical oxidation [4], This new process is the result of extensive studies on the selective Cl-hydroxyl group oxidation in the presence of O2 using a Pt or Pd catalyst modified with cocatalysts [5]. 

A fruitful, new extension of catalytic oxidation as a preparative method for special syntheses was established in 1935 when, in conjunction with experiments on the synthesis of L-ascorbic acid (3), Heyns found that selective oxidation of the various hydroxyl functions of carbohydrates was possible. It was shown that the primary hydroxyl group on C-1 of the pyranose form of L-sorbose (1) could be converted to the carboxyl group, giving a 65% yield of L-ajj/Zo-hexulosonic ( 2-keto-L-gulonic ) acid (2). (In formulas (1) and (2), the a-L anomer is depicted.)... 

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