Reichstein process

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The Reichstein process in chemistry is a combined chemical and microbial method for the production of ascorbic acid from D-glucose that takes place in several steps. This process was devised by Nobel Prize winner Tadeusz Reichstein and his colleagues in 1933 while working in the laboratory of the ETH in Zürich.[chronology citation needed]

Reaction steps[edit]

The reaction steps are:

The Reichstein process

The microbial oxidation of sorbitol to sorbose is important because it provides the correct stereochemistry.

Importance[edit]

This process was patented and sold to Hoffmann-La Roche in 1934.[chronology citation needed] The first commercially sold vitamin C product was either Cebion from Merck or Redoxon from Hoffmann-La Roche.[citation needed]

Even today industrial methods for the production of ascorbic acid can be based on the Reichstein process. In modern methods however, sorbose is directly oxidized with a platinum catalyst (developed by Kurt Heyns (1908–2005) in 1942). This method avoids the use of protective groups. A side product with particular modification is 5-Keto-D-gluconic acid.[3]

A shorter biotechnological synthesis of ascorbic acid was announced in 1988 by Genencor International and Eastman Chemical. Glucose is converted to 2-keto-L-gulonic acid in two steps (via 2,4-diketo-L-gulonic acid intermediate) as compared to five steps in the traditional process.[4]

Novel methods involve genetically modified bacteria.[5]

References[edit]

  1. ^ Wittko Francke und Wolfgang Walter: Lehrbuch der Organischen Chemie. S. Hirzel Verlag Stuttgart; 24. überarb Auflage 2004, ISBN 3-7776-1221-9; S. 480
  2. ^ Reichstein, T. und Grüssner, A. (1934): Eine ergiebige Synthese der L-Ascorbinsäure (C-Vitamin), Helv. Chim. Acta 17, S. 311–328
  3. ^ Brönnimann, C. et al. (1994): Direct oxidation of L-sorbose to 2-Keto-L-gulonic acid with molecular oxygen on Platinum- and Palladium-based catalysts. In: J. Catal. 150(1), S. 199–211; doi:10.1006/jcat.1994.1336
  4. ^ Harold A. Wittcoff, Bryan G. Reuben, Jeffery S. Plotkin. Industrial Organic Chemicals. John Wiley & Sons, 2012, Page 370
  5. ^ Hancock, RD. und Viola, R. (2002): Biotechnological approaches for L-ascorbic acid production. In: Trends in Biotechnology 20(7); S. 299–305; PMID 12062975;doi:10.1016/S0167-7799(02)01991-1

Literature[edit]

External links[edit]