chemistry

Rainer Ludwig Claisen

Rainer Ludwig Claisen 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 Rainer Ludwig Claisen rather than just read about it. In short: Rainer Ludwig Claisen (German pronunciation: [ˈʁaɪnɐ ˈklaɪzn̩]; 14 January 1851 – 5 January 1930) was a German chemist best known for his work with condensations of carbonyls and sigmatropic rearrangements. He was born in Cologne as the son of a jurist and studied chemistry at the University of Bonn in 1869, where he became a member of K.St.V.

Key takeaways

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

Reference excerpt

Rainer Ludwig Claisen (German pronunciation: [ˈʁaɪnɐ ˈklaɪzn̩]; 14 January 1851 – 5 January 1930) was a German chemist best known for his work with condensations of carbonyls and sigmatropic rearrangements. He was born in Cologne as the son of a jurist and studied chemistry at the University of Bonn in 1869, where he became a member of K.St.V. Arminia. He served in the army as a nurse from 1870 to 1871 and continued his studies at the University of Göttingen. He returned to the University of Bonn in 1872 and started his academic career at the same university in 1874. He died in 1930 in Godesberg am Rhein (near Bonn).

Career

Scientific contributions Described the condensation of aromatic aldehydes with aliphatic aldehydes or ketones in 1881. This variation of the now well-known aldol condensation reaction is called the Claisen–Schmidt condensation. Discovered (1887) the condensation reaction of an ester with an activated methylene group, now known as the Claisen condensation. Synthesis of cinnamates by reacting aromatic aldehydes with esters. The reaction is known as the Claisen reaction and was described by Claisen for the first time in 1890. Discovered the thermally induced rearrangement of allyl phenyl ether in 1912. He details its reaction mechanism in his last scientific publication (1925). In his honor, the reaction has been named the Claisen rearrangement. Synthesis of isatin via a process known as the Claisen isatin synthesis, described for the first time in 1879. Designer of a special distillation flask called the Claisen flask. With the increased modularity of modern glassware this functionality is often achieved with a Claisen adapter, of which there are many types, attached to a normal flask.

See also Cinnamic acid Dibenzylideneacetone Tetrahedral carbonyl addition compound

References

W Pötsch. Lexikon bedeutender Chemiker (VEB Bibliographisches Institut Leipzig, 1989) (ISBN 3323001850)

Notes

Illustrations

Worked examples

Example 1 — a first encounter with Rainer Ludwig Claisen

Start with the simplest possible case. Write down what Rainer Ludwig Claisen 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 Rainer Ludwig Claisen 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 Rainer Ludwig Claisen 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 Rainer Ludwig Claisen

In research: Rainer Ludwig Claisen 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 Rainer Ludwig Claisen 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: Rainer Ludwig Claisen is common in secondary-school and first-year university syllabi. It links to neighbouring topics 1851 births, 1930 deaths, 19th-century German chemists, so understanding it makes those chapters shorter.
In everyday life: Look for Rainer Ludwig Claisen 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 Rainer Ludwig Claisen in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Rainer Ludwig Claisen 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.
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Frequently asked questions

What is Rainer Ludwig Claisen in simple terms?

Why does Rainer Ludwig Claisen 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 Rainer Ludwig Claisen?

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 Rainer Ludwig Claisen.