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Terminal alkene

Terminal alkene is a science 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 Terminal alkene rather than just read about it. In short: In organic chemistry, terminal alkenes (alpha-olefins, α-olefins, or 1-alkenes) are a family of organic compounds which are alkenes (also known as olefins) with a chemical formula CxH2x, distinguished by having a double bond at the primary, alpha (α), or 1- position. This location of a double bond enhances the reactivity of the compound and makes it useful for a number of applications.

Terminal alkene — main illustration
Terminal alkene — illustration

Key takeaways

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

Reference excerpt

In organic chemistry, terminal alkenes (alpha-olefins, α-olefins, or 1-alkenes) are a family of organic compounds which are alkenes (also known as olefins) with a chemical formula CxH2x, distinguished by having a double bond at the primary, alpha (α), or 1- position. This location of a double bond enhances the reactivity of the compound and makes it useful for a number of applications.

Classification There are two types of alpha-olefins, branched and linear (or normal). The chemical properties of branched alpha-olefins with a branch at either the second (vinylidene) or the third carbon number are significantly different from the properties of linear alpha-olefins and those with branches on the fourth carbon number and further from the start of the chain. Examples of linear alpha-olefins are propene, but-1-ene and dec-1-ene. An example of a branched alpha-olefin is isobutylene.

Production A variety of methods are employed for production of alpha-olefins. One class of methods starts with ethylene which is either dimerized or oligomerized. These conversions are respectively effected by the alphabutol process, giving 1-butene, and the Shell higher olefin process which gives a range of alpha-olefins. The former is based on titanium-based catalysts, and the latter relies on nickel-based catalysts. A whole other approach to alpha-olefins, especially long chain derivatives, involves cracking of waxes:

R−CH2−CH2−CH−CH2−R' → R−CH=CH2 + CH2=CH−R' + H2 In the PACOL process (paraffin conversion to olefins), linear alkanes are dehydrogenated over a platinum-based catalyst.

Applications Alpha-olefins are valued building blocks for other industrial chemicals. A major portion of medium or long chain derivatives are converted to detergents and plasticizers. A common first step in making such products is hydroformylation followed by hydrogenation of the resulting aldehydes. Long chain alpha-olefins are also oligomerized to give medium molecular weight oils that serve as lubricants. Alkylation of benzene with alpha-olefins followed by ring-sulfonation gives linear alkylbenzene sulfonates (LABS) which are biodegradable detergents. Competing often with these petroleum-derived products are derivatives of fatty acids, such as fatty alcohols and fatty amines. Low molecular weight alpha-olefins (butenes, hexenes, etc.) are used as comonomers, which are incorporated into polyethylene. Some are subjected to olefin metathesis as a route to propylene.

See also Vinyl group

References

Illustrations

Terminal alkene: Hex-1-ene, a typical alpha-olefin. The blue numbers show the IUPAC numbering of the atoms in the backbone chain of the molecule. The red symbols show the common nomenclature labeling of the main chain atoms. The double bond of an alpha olefin is between the #1 and #2 (IUPAC) or α and β (common) carbon atoms.
Hex-1-ene, a typical alpha-olefin. The blue numbers show the IUPAC numbering of the atoms in the backbone chain of the molecule. The red symbols show the common nomenclature labeling of the main chain atoms. The double bond of an alpha olefin is between the #1 and #2 (IUPAC) or α and β (common) carbon atoms.

Worked examples

Example 1 — a first encounter with Terminal alkene

Start with the simplest possible case. Write down what Terminal alkene claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, 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 Terminal alkene 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 Terminal alkene 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 Terminal alkene

In research
Terminal alkene appears in science 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 Terminal alkene 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
Terminal alkene is common in secondary-school and first-year university syllabi. It links to neighbouring topics Alkenes, so understanding it makes those chapters shorter.
In everyday life
Look for Terminal alkene 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 Terminal alkene in 20 minutes

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

Frequently asked questions

What is Terminal alkene in simple terms?

In organic chemistry, terminal alkenes (alpha-olefins, α-olefins, or 1-alkenes) are a family of organic compounds which are alkenes (also known as olefins) with a chemical formula CxH2x, distinguished by having a double bond at the primary, alpha (α), or 1- position. This location of a double bond…

Why does Terminal alkene matter?

Because it connects several science 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 Terminal alkene?

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 Terminal alkene.

Tags

  • Alkenes

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