100 Nano-Stories: Name Alkanes vs. Cyclo-Hexanes!

Episode #34: Final Alkane Explanation!

Carlos Manuel Jarquín Sánchez
6 min readFeb 22, 2021

Preface! → ✨

It’s your favorite material science & nanotechnology enthusiast reporting back for another article! In the last article, I explained how the surface area can impact the aerogel and how we can increase production!

For today’s article, I will talk about the best way to name an alkane and a cyclo-alkane. This will be the last time I will discuss alkanes since we will be moving on to more in-depth topics in organic chemistry & aerogels.

Anyways, reader, what are we waiting for? Let’s discover more about everyone’s favorite science!

Naming Alkanes: Steps! → 😤

Preparations! → 🔑

Let’s use a photo of an organic compound that we will solve today!

Our Alkane Example!

This may look like a bunch of lines, but here are the steps to name & identify the alkane!

Remember, each pointy end of each line is a carbon atom with 4 hydrogen atoms (CH4). If it helps, here is where you can find the carbons + hydrogen groups:

Step 1! → 🔑

Each gray line is where a carbon group can be found. But now that we know where we can count for the carbons, we need to find the next step: Find The Longest Carbon Chain.

The longest carbon chain can be found by just counting these gray lines and finding which of these lines add up the most. If it helps, we can number the longest carbon chain:

The Longest Carbon Chain has 8 carbons in it, so that means it is an octane. Octane is the “backbone” of how the alkane will be named, which means the term “octane” will be added to the end of the alkane name.

Step 2! → 🔑

The next step is to number the longest carbon chain to find the substituents & give them the lowest number possible in the naming of the alkane! A substituent in an alkane is carbons that are not part of the main carbon chain or part of the longest carbon chain.

If we notice the photo from above, there are two lines, and both of them contain the same length! This means they are methyls! The suffix “yl” is used for any carbon group that is not part of the longest carbon chain.

But in terms of adding numbers to the main carbon chain, we want to give these two methyl groups the smallest number possible.

If you notice in the photo, the first methyl group is located on carbon #2 of the main carbon group if we count from the right.

If we count the main carbon chain from the left, the first methyl group is located on carbon #4. In this case, count from the right to get the least value of the methyl groups.

Step 3! → 🔑

Now it’s time to name the organic compound! Because we know that the two methyl groups are located on carbon numbers 2 & 5, we start with the numbers “2,5”. But because there are two methyl groups: we use the term “di”, and then we use “methyl”. Finally, we add the term “octane”.

The final name for this alkane is 2,5 dimethyl octane.

Naming Cyclo-Alkanes: Steps! → 😤

Now let’s find the best way to name cyclo-alkanes! Let’s bring out our example for today!

Step 1! → 🔑

The first step is to name the longest carbon chain in the photo.

Don’t get confused with the cyclo-alkane that is shaped like a pentagon! It is actually connected to the main carbon chain! Highlighting the longest carbon chain will help you visualize this:

Step 2! → 🔑

The next step is to number the longest carbon chain so that we can give the substituents the lowest value possible. Substituents are the carbon chains that are not part of the longest carbon chain.

If we count from the left of the carbon chain, the cyclo-pentane has a value of four. But if we count from the right of the carbon chain, the cyclo-pentane has a value of three. So three it is! Here is a visual diagram:

The main carbon chain consists of 6 carbons, which is hexane!

Step 3! → 🔑

The final step is to name this organic compound! We know that the cyclo-alkane is a pentagon, which would make it a cyclo-pentane! But because it is not part of the main carbon chain, we use the suffix “yl”. So. . .

  • Cyclopentane → Cyclopentyl

But because the Cyclo - Pentyl is on carbon # 3 of the main carbon chain, we will name this organic compound with the number (3). Next, we include the substituent (cyclopentyl), followed by hexane.

Here is the final answer:

Closing Thoughts! → 💭

We have completed our alkane studies! Aren’t you happy, reader? Now we can slowly move on to the aerogel chemistry and the manufacturing process!

The steps for finding an alkane & cycloalkane are:

  • 1) Find the longest carbon chain and properly name it.
  • 2) Number the longest carbon chain. It will help you give the lowest value to the substituents.
  • 3) Figure out the substituents & name them.
  • 4) To fully name the alkane, use an alphabetical order of names. The prefixes “iso”, “sec”, “tri”, “tert”, “penta”, “hexa”, “cyclo” don’t count.
  • 5) The main carbon chain will always be the last section of the name.

See you tomorrow for my thoughts on aerogel production & scaling up this wonder material!

Vocabulary! → 📓

Alkane → An organic compound that is only made out of carbon & hydrogen atoms, only single covalent bonds.

Cycloalkane → The Carbon Atoms are connected in the form of a ring, and the carbon bonds are single-bonded to other atoms.

Substituents → Carbon Rings or Carbon molecules that are not part of the longest carbon chain (main carbon chain). It can also end with “yl” if you are looking at an image of a chemical in organic chemistry.

Connect →🔗



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