Stability of Alkenes: Factors & Examples

An error occurred trying to load this video.

Try refreshing the page, or contact customer support.

Coming up next: E2 Elimination & Mechanism Reaction: Definition & Examples

You're on a roll. Keep up the good work!

Take Quiz Watch Next Lesson
 Replay
Your next lesson will play in 10 seconds
  • 0:04 What Are Alkenes?
  • 0:47 Stability
  • 2:41 Zaitsev & Hoffman Products
  • 3:40 Lesson Summary
Save Save Save

Want to watch this again later?

Log in or sign up to add this lesson to a Custom Course.

Log in or Sign up

Timeline
Autoplay
Autoplay
Speed Speed

Recommended Lessons and Courses for You

Lesson Transcript
Instructor: Amanda Robb
In this lesson, we'll be learning about the factors that help determine alkene stability. We'll go over substitution, orientation, and conjugation, and discuss Zaitsev and Hofmann products.

What Are Alkenes?

Think about how much plastic you use each day. From grocery bags to plastic packaging on our food, plastic is just about everywhere in our lives. If this feels relatable, chances are you've already had quite a bit of experience with alkenes. Alkenes are hydrocarbon chains with at least one double bond. They make an appearance in the production of lots of consumer goods, such as the thick plastic we see in buckets and crates for storage, wire coatings like those on our phone chargers, and the thin plastics we find in shopping bags and packaging.

One way that alkenes can be produced is through elimination reactions. In elimination reactions, a substituent is removed from a hydrocarbon molecule, producing a double bond between adjacent carbon atoms in the process.

Stability

During elimination reactions, more than one alkene product can be made. So, how do we know which product to expect? The most stable product is usually the favored product, with some exceptions. Burt how do scientists know which products are more stable? There are three main things that determine stability of an alkene product: the number of substituents, their orientation, and hyperconjugation. Let's look at each in detail next.

Substituents

Alkenes have substituents, hydrogen atoms attached to the carbons in the double bonds. The more substituents the alkenes have, the more stable they are. Thus, a tetra substituted alkene is more stable than a tri-substituted alkene, which is more stable than a di-substituted alkene or an unsubstituted one.

Orientation

In general, more substituted alkenes are going to be more stable compared to less substituted alkenes. But, what if two alkenes have the same number of substituents, but in a different orientation? Cis isomers have substituents on the same side of the double bond, whereas trans isomers have substituents on opposite sides.

The trans orientation is going to produce a more stable product due to steric hindrance, which is a physical limitation of the substituents. In a cis molecule, the two substituents may repel each other because of molecular interactions. But, in a trans molecule, each substituent has enough space, making it more stable.

Hyperconjugation

The last factor in alkene stability has to do with hyperconjugation. This is a force that occurs between the p or pi orbitals of the carbon atoms in the double bond with sigma orbitals of the carbon atoms in the substituted groups. The overlap of these orbitals helps the atoms share electrons and makes the molecule more stable. This is why alkenes with more substituent groups are more stable than those with fewer. Additional substituents can increase hyperconjugation and thus molecule stability.

To unlock this lesson you must be a Study.com Member.
Create your account

Register to view this lesson

Are you a student or a teacher?

Unlock Your Education

See for yourself why 30 million people use Study.com

Become a Study.com member and start learning now.
Become a Member  Back
What teachers are saying about Study.com
Try it risk-free for 30 days

Earning College Credit

Did you know… We have over 200 college courses that prepare you to earn credit by exam that is accepted by over 1,500 colleges and universities. You can test out of the first two years of college and save thousands off your degree. Anyone can earn credit-by-exam regardless of age or education level.

To learn more, visit our Earning Credit Page

Transferring credit to the school of your choice

Not sure what college you want to attend yet? Study.com has thousands of articles about every imaginable degree, area of study and career path that can help you find the school that's right for you.

Create an account to start this course today
Try it risk-free for 30 days!
Create an account
Support