chemistry

Reichstein process

Reichstein process is a chemistry topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Reichstein process rather than just read about it. In short: The Reichstein process in chemistry is a combined chemical and microbial method for the production of ascorbic acid from D-glucose in five 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.

Key takeaways

Reichstein process belongs to chemistry; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Reichstein process to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Reichstein process from memory before moving on to harder problems.

Reference excerpt

The Reichstein process in chemistry is a combined chemical and microbial method for the production of ascorbic acid from D-glucose in five 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.

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 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 (to Diprogulic acid) 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. 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.

Importance This process was patented and sold to Hoffmann-La Roche in 1934. The first commercially sold vitamin C product was either Cebion from Merck or Redoxon from Hoffmann-La Roche. 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. 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. Though many organisms synthesize their own vitamin C, the steps can be different in plants and mammals. Smirnoff concluded that “..little is known about many of the enzymes involved in ascorbate biosynthesis or about the factors controlling flux through the pathways". There is interest in finding alternatives to the Reichstein process. Experiments suggest that genetically modified bacteria might be commercially usable.

References

Literature Boudrant, J (May 1990). "Microbial processes for ascorbic acid biosynthesis: a review". Enzyme Microb. Technol. 12: 322–9. PMID 1366548. Bremus, C; Herrmann, U; Bringer-Meyer, S; Sahm, H (June 2006). "The use of microorganisms in L-ascorbic acid production". J. Biotechnol. 124: 196–205. doi:10.1016/j.jbiotec.2006.01.010. PMID 16516325.

External links http://www.chemieunterricht.de/dc2/asch2/a-synthe.htm Der Schweizerische Weg zur Viamin-C-Synthese

Worked examples

Example 1 — a first encounter with Reichstein process

Start with the simplest possible case. Write down what Reichstein process claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In chemistry, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Reichstein process before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Reichstein process ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Reichstein process

In research: Reichstein process appears in chemistry research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Reichstein process in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Reichstein process is common in secondary-school and first-year university syllabi. It links to neighbouring topics Organic reactions, so understanding it makes those chapters shorter.
In everyday life: Look for Reichstein process outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Reichstein process in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Reichstein process means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Reichstein process out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Reichstein process in simple terms?

Why does Reichstein process matter?

Because it connects several chemistry ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Reichstein process?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Reichstein process.