Ester Nomenclature

Concept: Concept: Ester Nomenclature

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Video Transcript

On this page, we’re going to learn how to name esters. Esters are actually one of the hardest functional groups to name that’s because ester is one of the only functional group that the name of the functional group is not found anywhere in the nomenclature. Meaning that if you have an ester, you're not going to actually see the name ester anywhere. So what is the name? It turns out that an ester is names of two components. Imagine that you’ve got an ester. Remember that the general structure is COOR. What they consider is that everything on this side is an alkyl group. You name this as an alkyl group. Then the way that they name the other side is they think this looks a lot like, this side here, looks a lot like a carboxylic acid but without the H. What do you call it when a carboxylic acid is missing its H? You call it a carboxylate. It’s an alkyl carboxylate. That sucks. We name it as an alkyl carboxylate. You have to determine what that name is going to be. I’ll do a work example here and then I'll let you guys go to do it yourself.
Here. We've got an ester, obviously. We have an alkyl group and a carboxylate. The way we would name is the alkyl group is ethyl, two-carbon chain. The carboxylate could be named in one of two ways. It could be named as the common name which should be the two-carbon chain which should be acetic acid, which should be acetate because acetate is the negative anion or, that’s in the common name. Or it could be named as ethanoate because it’s ethanoic acid, so that would be IUPAC. Both of these would be correct. You’ll hear ethyl acetate. You'll hear ethanoate. Obviously, acetate is way more common. You hear that everywhere. Ethyl acetate would be the name of that structure there. Let's go ahead and move on to this practice problem. Let’s see if you can get it right.