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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 Tadeus Reichstein and his colleagues in 1933 while working in the laboratory of the ETH in Zürich. == Reaction steps == The reaction steps are: * hydrogenation of D-glucose to D-sorbitol, an organic reaction with nickel as a catalyst under high temperature and high pressure. * Microbial oxidation or fermentation of sorbitol to L-sorbose with acetobacter〔Wittko Francke und Wolfgang Walter: ''Lehrbuch der Organischen Chemie''. S. Hirzel Verlag Stuttgart; 24. überarb Auflage 2004, ISBN 3-7776-1221-9; S. 480〕 at pH 4-6 and 30 °C. * protection of the 4 hydroxyl groups in sorbose by formation of the acetal with acetone and an acid to Diacetone-L-sorbose (2,3:4,6−Diisopropyliden−α−L−sorbose) * Organic oxidation with potassium permanganate followed by heating with water gives the 2-Keto-L-gulonic acid * The final step is a ring-closing step or gamma lactonization with removal of water.〔Reichstein, T. und Grüssner, A. (1934): ''Eine ergiebige Synthese der L-Ascorbinsäure (C-Vitamin)'', Helv. Chim. Acta 17, S. 311–328〕 * Intermediate 5 can also be prepared directly from 3 with oxygen and platinum : The microbial oxidation of sorbitol to sorbose is important because it provides the correct stereochemistry. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Reichstein process」の詳細全文を読む スポンサード リンク
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