Naming Ethers - Online Tutor, Practice Problems & Exam Prep

Ethers, characterized by the functional group ROR, can be named using common or IUPAC naming conventions. Common names are formed by naming the two alkyl groups in alphabetical order followed by "ether," such as methylpropyl ether. For IUPAC naming, the larger alkyl group serves as the root, with the smaller group named as an alkoxy substituent (e.g., methoxy for a one-carbon chain). The full name includes the position of the substituent, resulting in names like 1-methoxypropane. Understanding these naming conventions is essential for identifying and communicating about ethers in organic chemistry.

How to name ethers using the common naming system.

Now let's talk about naming ethers. So it turns out that ethers are very simple molecules. As you guys remember, the functional group is ROR. And what that means is that since they're very simplistic molecules, these are actually going to be a few molecules that we name with both common names and IUPAC names. Now if you guys remember, IUPAC names are the ones that were developed after 1919 at the IUPAC convention. That means every name that we have for a molecule before that date is considered a common name. And it turns out that because ethers are so simple, a lot of times we're going to use common names more often than the IUPAC names for them. So let's actually go ahead and start off learning the common way first and then I'll teach you guys the IUPAC way as well.

So it turns out that the common name, the reason we use it so much is because it's very easy to use. All it is is that you name the two R groups in alphabetical order and you end with the word ether. Okay? So, I'm sure you guys have maybe already started lab and you maybe have worked with an ether in lab. They have diethyl ether, dimethyl ether. That just means that the two R groups are either methyls or ethyls. In this case, this would be a methylpropyl ether because as you can see, I have an ROR functional group and I'm just naming the two alkyl groups according to their size. So I have one carbon and three carbons. That'll be methylpropyl ether. See how easy that is? So most of the time, we're going to use the common naming system for very simple ethers.

How to name ethers using the IUPAC naming system.

But it does turn out that sometimes ethers get more complex, sometimes they have bigger branches on one side and it might be advantageous to use IUPAC. So let's go ahead and see what this same ether would look like if we used the IUPAC convention. For IUPAC, what we would do is we would use the same rules that we use for naming alkanes, but we would name the OR group as a substituent instead. So what I would say is which of my R groups is the biggest one? In this case, I have a one-carbon side and a three-carbon side. So obviously, I'm going to use my three-carbon side to be my root. And in this case, my root is going to be propane. So I know that I'm dealing with propane. Now I just have to name the OR group that's attached to it. And the way that we name OR groups is as alkoxy groups. So alk just stands for the number of carbons in the chain. So you can imagine that if it was a four-carbon chain, it would be butoxy. Four carbons. So in this case, this one's really easy. I just have a one-carbon chain attached directly to the O, so this would be considered methoxy. But now it's not enough just to say that it's methoxypropane because we know that propane actually has 2 positions. It has one at the end, which would be the first position here. And it also has the middle position. Now you're wondering what about the last one? Well, remember that Carbon 3 is the same as Carbon 1 because it's symmetrical. I could always just put it on 3 and that would just be my starting point. But I have to name the location, so obviously what I would do is it would give my priority to the substituent. So this would be one-methoxypropane starting at the first carbon. Pretty easy, right? Overall, ethers are pretty easy to name. Let's go ahead and do a practice example. In this example, I want you guys to figure out what the common name would be and what the IUPAC name would be, both of them together, for this molecule. So I want 2 individual names for this same ether. Go ahead and try.

Provide the correct common name of the following ether.

Let's start off with the common name. So for this one, the common name was actually a little bit more challenging because I'm starting off with an ether that has a little bit more branching than the last one. For example, this R group here should have been really easy for you guys to name. That's an ethyl group. But maybe some of you guys forgot the name of the other R group or maybe you just got it wrong. I know that you'd be surprised how easy it is to get these wrong. This is actually a 4 carbon group that's attached to the primary carbon and then it has an isopropyl looking thing at the end. So this is one of the common substituents that we call isobutyl. Okay? So see, a few of you guys already got that wrong or didn't know how to do that. And I'm not saying that to rub it in your face or anything. I'm just saying that that's why common doesn't work so well. The bigger the branches get, the worse it is to use common. Okay? The common naming system. So in this case, I would put them in alphabetical order. Now, remember, there's another rule which says that "iso" actually does count towards alphabetical order, the "I" in "iso". So I would say that this name would be ethylisobutyl ether. Okay? So, not terrible. Okay? But at the same time, you can imagine, I start adding carbons to this and it's going to start to get kind of impossible to name with the common name.

Provide the correct IUPAC name of the following ether.

And that's why we have IUPAC. Because IUPAC is going to be I can apply it to any ether. It could be 100 carbons long and I would be able to systematically name it. Okay? Except you don't know the prefix for 100 carbons, but don't worry, it won't get that high. So in this case, my root is going to be what? What do you guys think? It would be the 3 carbon chain over here. Okay? Because I'm just looking for the longest continuous chain. So I would say that this is going to be I'm just going to list out the components like I usually do. The root is going to be propane. Okay? Then what are my substituents going to be? It actually turns out that I have 2 substituents now. I have a methyl group here and I have a methoxy here. So now I just have to figure out what the numbering would be and the ethoxy group is going to get priority over the alkyl group. So I'm going to make this my number one carbon. If, for example, if I had had the methyl if I had had an alkyl group on the other side or whatever, I would have still picked the OR group. So now we're going to go ahead and put this together. So we just have to put it in alphabetical order and that's going to be 1-ethoxy-2-methylpropane. So as you can see, the name is a little bit longer. Obviously, it has numbers and stuff. But as I was saying before, as my ethers get bigger and bigger, it's going to be smarter to use IUPAC because it's just a simple rule that you can apply for everything. Okay? Awesome. So I hope that wasn't so bad, right? Let's go ahead and move on to the next topic.

Here’s what students ask on this topic:

What is the common naming convention for ethers?

The common naming convention for ethers involves naming the two alkyl groups attached to the oxygen atom in alphabetical order, followed by the word 'ether.' For example, if the ether has a methyl group (CH₃) and a propyl group (C₃H₇), it would be named methylpropyl ether. This method is straightforward and often used for simple ethers.

How do you name ethers using the IUPAC system?

In the IUPAC system, ethers are named by identifying the larger alkyl group as the root and naming the smaller alkyl group as an alkoxy substituent. For example, in an ether with a one-carbon group (methoxy) and a three-carbon group (propane), the IUPAC name would be 1-methoxypropane. The position of the alkoxy group is indicated by a number, ensuring clarity in the structure.

What is the difference between common names and IUPAC names for ethers?

Common names for ethers are simpler and involve naming the two alkyl groups in alphabetical order followed by 'ether.' In contrast, IUPAC names use the larger alkyl group as the root and the smaller group as an alkoxy substituent, with the position of the substituent specified. For example, diethyl ether (common name) is named ethoxyethane in IUPAC nomenclature.

Can you provide an example of naming an ether using both common and IUPAC conventions?

Sure! Let's consider an ether with a methyl group (CH₃) and a propyl group (C₃H₇). The common name for this ether is methylpropyl ether. Using the IUPAC system, the larger group (propane) is the root, and the smaller group (methoxy) is the substituent. The IUPAC name is 1-methoxypropane, indicating the methoxy group is attached to the first carbon of the propane chain.

Why are common names often used for simple ethers?

Common names are often used for simple ethers because they are straightforward and easy to remember. Ethers are simple molecules, and the common naming system, which involves naming the two alkyl groups in alphabetical order followed by 'ether,' is less cumbersome than the IUPAC system. This simplicity makes common names more practical for everyday use in labs and discussions.