20. Carboxylic Acid Derivatives:NAS
Base-catalyzed Transesterification occurs when an ester is exposed to an alkoxide base with a dissimilar alkyl group. Now, do we think this a good thing? Stay tuned for the answer!
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on this page. We're gonna discuss the reaction called transit stratification. So base catalyzed transit certification occurs when an Esther is exposed to an Alcock side base with a dissimilar alcohol group. Okay, so if I'm using in Alcock side base, let's say that I was in a basic environment, okay? Because this base catalyzed and imagine that my alcohol, instead of having our group, our group that I have on my alcohol group, I have our prime. Our prime just means it's different. It's something different. Maybe once a metal and one's enough. Okay, What's gonna wind up happening is after it reacts, we're gonna wind up getting another Esther. Okay, so nothing seems like nothing changed, but wait, the our group is gonna be different. So I'm gonna get one our group transferring with another or substituting with another. Okay, so this happens, guys, because in equilibrium, all these oases are gonna be constantly or are groups. Whatever. Are we constantly substituting back and forth and back and forth? If you have different alcohol groups in different positions, they're gonna wanna blending together, and you're gonna wind up getting oh, are groups of both types on on your Esther. And that's very problematic, because you want to make sure when you have a nester, you wanna make sure that has all the same alcohol group you don't want. Ah, bunch of different random alcohol groups. Okay, now there is one way this can be avoided. Guys, the way this could be avoided is simply to Onley exposed Esther's toe Alcock sides with the same our group. Okay, so imagine I'm just gonna bring this reaction down a little bit. Imagine that now I have Let's say are one okay? And I'm exposing it two and Alcock side. That is O R. One negative. What's gonna happen? Well, guys in equilibrium, it's gonna switch, and it's gonna do this whole mechanism that I'm gonna show you. But are we gonna be able to actually tell that it's happening? The answer is no reaction in terms of, Does it have any effect on my product? No, because I am going to get Substitution is taking place. But since my our groups are identical, I won't be able to notice this difference. I won't be able to notice that erection is actually taking place because it's not really mattering for my reaction. The only time it would matter is if I have a different our group. So let's say it was R one and R two. Now I'm gonna get a mixture of our groups. Trans s terrifying. Okay, so in this next video, I'm gonna show you guys the mechanism and heads up. It's easy.
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All right. So let's say that I do mess up and I have my methyl ester, Okay? And I forget that it's a methyl ester, and I expose it to a fox side, so Oh, ch two ch three Negative. Okay, so I wasn't supposed to do that. I should have only used meth oxide here because I know my fox. I would avoid this situation. But let's say I use a fox side by mistake. Well, this is what happens. You wind up getting a nuclear filic a seal substitution, you wind up forming a tetra Hydro intermediate. And that's gonna have now, um, O C H three oh, ch two ch three. And now what happens? Well, now which group gets kicked out in my nes reaction, it could be either one. The point here is that it's gonna be a mixture of both, so I'm gonna wind up getting two different Esther's. I'm gonna wind up getting the Esther that forms when it kicks out the metal. Right. So that would be It's gonna wind up being an ethyl ester, right? But I'm also going to get the one that forms if it kicks out the original molecule. Okay, so that would be a methyl ester. Okay, so anyway, you should never draw multiple arrows like that on the same on the same re agent. Okay, so that's kind of me. Just kind of showing you conceptually what's going on. Let's just say that you are going forward, your transistor defying. So you're kicking out the O. C. H three. Well, then you're gonna get This is a product you're gonna wind up getting an ethyl ester okay, as a product. So, again, this is problematic, guys, and there's gonna be important later on, there's gonna be more reactions that we're gonna use Esther's for. And so it's gonna be important to always using Alcock side of the same base of the same our group. Because if I can keep those are groups consistent than transit Certification doesn't matter to me anymore. Because even if the reaction is taking replace, I can't appreciate it because nothing is actually happening. Okay, so I hope that made sense guys really easy mechanism. So let's move on to the next video
Additional resources for Transesterification
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