- Carboxylic acid derivatives questions
- Nomenclature and properties of acyl (acid) halides and acid anhydrides
- Nomenclature and properties of esters
- Nomenclature and properties of amides
- Reactivity of carboxylic acid derivatives
- Nucleophilic acyl substitution
- Acid-catalyzed ester hydrolysis
- Acid and base-catalyzed hydrolysis of amides
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How to name acyl (acid) chlorides and acid anhydrides and how to analyze their physical properties. Created by Jay.
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- If acetyl chloride reacts so violently with water, then how is it formed? Upon first glance that looks to me like a substitution/dehydration reaction between the carboxylic acid and HCl. Why would the product even form if it readily reacts with the water that it would produce?(6 votes)
- There are reaction conditions and reaction apparatuses which can remove water during the reaction. For example, I can set up a concomitant reaction in the same apparatus where the reactant is water, the reaction equilibrium strongly favors the products and the products are not reactive with acetyl chloride. But chemists have ways. All the best.(6 votes)
- So to name acids we have to know the anions names but how do we identify the anion names like ide, ate, or ite? What about when we are not talking about polyatomic ions like just bromine how would we identify if its name is bromide, or bromate, or bromite?(2 votes)
- Some of these links may be of help.
- I don't understand the reaction of carboxylic acid with alcohol(2 votes)
- A carboxylic acid reacts with an alcohol to form an ester and water.
RCO-OH + H-OR' → RCO-OR' + H-OH(4 votes)
- why do acid anhydrides has higher priority than acyl halides when in fact acyl halides are more reactive than anhydrides?(2 votes)
- There is a certain priority of the functional groups. First you name carboxylic acid, then you name ester, third you name amides, after that you name aldehydes. In the fifth you name ketones and alchohol is the next. At the seventh you name amines and lastly you name alkanes.(From my textbook.) I cannot help you about acid anhydrides and acyl halides.(2 votes)
- Why would RCOCl react violently with water? Sorry if it's too stupid to ask(2 votes)
- The smaller acid chlorides like acetyl chloride react vigorously with water. As the size of the alkyl group increases, the rate of reaction decreases, but most acid chlorides will react with cold water.(2 votes)
- We can use benzene carboxylic acid instead of benzoic acid. Can we use benzene carboxylic anhydride instead of using benzoic anhydride ?(2 votes)
- how do i name an oxyacids(1 vote)
- There's different name rules for Binary Acids and Oxyacids/Oxoacids. For Oxyacids/Oxoacids, they are acids with Oxygen in their chemical structure (ex: H₃PO₄). There's two variations to this:
- For those that have compounds that end with "-ate" (ex: phosphate, bromate, etc.), change the "-ate" ending to "-ic" and then add "acid" at the end. So, if it was HNO₃, because it has a nitrate ion in it (NO₃) the ending would change into "-ic" to make "Nitric Acid."(1 vote)
- At7:40, if you choose the IUPAC naming, does the acetic benzoic anhydride change to benzoic ethanoic anhydride? Thanks(1 vote)
- Yes. You should always name the substiutuent in an alphabetical order (see the nomenclature of alkanes and cycloalkanes video 2) except for some special cases that the order without using the alphabetical order, such as methyl ethyl ketone (I think that this is the only one, but there maybe some other exceptions which that you can use them.) You should be becareful that the things that indicates the number of a certain substiutuent, such as di, tri, tetra, e.t.c. Also, don't count in the N which indicates the positions of the amides(after this and the next video, you can see the nomenclature of amides)
Please forgive my potential wrong spelling and grammatical mistake(if there are some). Thank you!(1 vote)
- On the reaction of acetyl chloride with acetic acid in the presence of pyridine , how ACETIC ANHYRIDE is formed ?
please tell the mechanism.(0 votes)
Lecturer: The next few videos we're going to look at the nomenclature and properties of carboxylic acid derivatives. Let's start with an acyl halide. Here's our general structure of an acyl halide. On the left side we have an acyl group, on the right side we have a halogen. You could also call this acid halides. They're derived from carboxylic acids. If we look at this carboxylic acid on the left here, a two carbon carboxylic acid, we could convert that to a two carbon acyl halide over here on the right. If we want to name our acyl halide we have to think about the name of the carboxylic acid. This, of course, is acetic acid. Let's go ahead and write out acetic acid here. If we want to name the corresponding acyl halide we need to think about dropping the -ic ending, and then the acid. We drop -ic and acid, and we add -yl and then the halide. Let's go ahead and write that out, so we drop the -ic and we add the yl and then we add the halide. We have a chlorine here so we're going to write chloride. We would call this acetyl chloride. Let's go ahead and show that right here. We add the -yl and then we add the halide portion. We could have also called this ethanoic acid. Ethanoic acid would be the IUPAC name but everyone says acetic acid. If we were to call this ethanoic acid, once again think about drop your -ic and then the acid part, drop this portion, then add -yl and then chloride. Let's go ahead and write that in here. We go ahead and add the -yl in and then the chloride like that. That would be ethanoyl chloride as our name. Let's go ahead and show this portion, once again, the -yl portion and then our halide. In terms of physical properties of acyl halides we need to think about the interaction of two molecules here. Let me go ahead and draw in another molecule of acetyl chloride. Acetyl chloride has a boiling point of approximately 51 degrees Celsius. Let me go ahead and write that in, so approximately 51 degrees Celsius. We know that acetyl chloride is a polar molecule. The oxygen here is more electronegative than this carbon, so we have a partial negative and we have a partial positive. This chlorine is also withdrawing electron density from our partially positive carbon, so we have a polar molecule. Acetyl chloride is polar right here. This is polar. Same molecule so this is polar. We have a partial negative, partial positive. Once again this chloride is also withdrawing electron density this way. We have two polar molecules interacting which we know is a dipole dipole intermolecular force. There's an attractive force between these molecules which is dipole dipole. Let me go ahead and write that. It's a dipole dipole interaction with molecules of actyl chloride. We know that dipole dipole interactions are stronger than London dispersion forces, so acetyl chloride has a higher boiling point than say a two carbon alkane, like ethane. It's a little bit harder to pull these molecules apart than it is to pull molecules of ethane apart, therefore this boiling point is higher than that for a two carbon alkane. However this boiling point is lower than that of acetic acid. To think about that we'll need to draw in another molecule of acetic acid. Let me go ahead and do that. Drawing in another molecule of acetic acid. We can see that there's opportunities for hydrogen bonding. There's a hydrogen bond here, and a hydrogen bond here. Hydrogen bonding, go ahead and write that. Hydrogen bonding is the strongest type of intermolecular force. Therefore the boiling point of acetic acid is going to be higher, it's somewhere around 118 degrees Celsius. It's harder to pull these two molecules apart because hydrogen bonding is a stronger intermolecular force than dipole dipole. That gives you some idea of the boiling point of acyl halides. In terms of solubility in water you can't really say that something like acetyl chloride is soluble in water because it reacts so violently with it. Acetyl chloride is extremely reactive and it reacts very quickly and often violently with water, so we can't really say that it dissolves in water. Let's move on to acid anhydrides. Let's look at how to name an acid anhydride. Acid anhydrides can be thought of as being derived from carboxylic acids too. If we look over here in the left once again we have acetic acid here, this is acetic acid. If we take two molecules of acetic acid and combine them we can form an acid anhydride. Let's think about what happens. We're going to lose water here and the word anhydride means without water. If we take off the water and take this portion, take this acyl group and this over here and stick them together, then we form our anhydride over here on the right. Because our anhydride was formed from acetic acid we call this acetic anhydride. These are pretty simple names. You keep the acetic part and drop the acid, and just add anhydride. This is acetic anhydride. If you thought of acetic acid as ethanoic acid, if you prefer to use the IUPAC name, ethanoic acid. Let me write ethanoic acid here. Once again just drop the acid part and add anhydride. You could call this ethanoic anhydride. Ethanoic anhydride. Once again anhydride meaning without water. Let's look at how to name another anhydride. Let me go down here and get some more room. We're trying to name this anhydride over here on the right. To do that we need to think about the carboxylic acid, from which it can be thought of as being derived. Here we have two molecules of benzoic acid. Let's go ahead and write benzoic acid here. I'm not talking about exact chemical reactions, I'm just thinking about the acid anhydride and how to put it into the different carboxylic acids. If we do the same thing we did before, we think about the term anhydride being loss of water, we take out water here and stick those together, once again you can see we form the anhydride on the right. This portion plus this portion gives us our acid anhydride. Once again we're not doing exact chemical reactions here. Just for the sake of nomenclature we can just drop the acid and add anhydride. This would be benzoic anhydride. This would be benzoic anhydride, like that. Let's look at another example. This time we don't have symmetry. When I'm thinking about some carboxylic acids for this one, over here on the left I recognize benzoic acid. Let me go ahead and write that down. Benzoic acid is being present. If I think about over on the right side, this portion, if I think about a carboxylic acid this way I see that's acetic acid. I have benzoic acid and acetic acid. To name our anhydride we drop the acid part and we're going to add anhydride. We have to think about using the alphabet here. A comes before B, so to write the name of our anhydride we would write acetic benzoic anhydride. Acetic benzoic anhydride. Once again when you see an anhydride and you're trying to name it just think about the carboxylic acids and that will help you figure out the name. In terms of physical properties of acid anhydrides let's look at an example here. Over here on the left we have acetic anhydride, which is a polar molecule. It's moderately polar because we have these carbonyls here. The oxygen is partially negative, this carbon down here is partially positive, the same thing for all these carbonyls. It's a moderately polar molecule. That's a negative sign right there. There's going to be some attraction between these molecules. There's going to be some attraction between the negative and the positive charges. We have a fairly polar molecule and a fairly polar molecule, so we can say that there's some dipole dipole interaction present. Between molecules of acetic anhydride there's some dipole dipole interaction. There's also of course London dispersion forces as well. The boiling point for acetic anhydride turns out to be approximately 140 degrees Celsius. Let's go ahead and write that in here, so approximately 140 degrees Celsius. We can compare that to a carboxylic acid that's similar in terms of number of carbons and oxygens. For acetic anhydride we had one, two, three, four carbons. Over here on the right this is butanoic acid. We have one, two, three, four carbons. Then we have two oxygens for butanoic acid and we have three oxygens for acetic anhydride. They're similar in terms of sizes, but when we think about comparing their boiling points, over here on the right butanoic acid has a boiling point of approximately 164 degrees Celsius, it has a higher boiling point because once again there's some hydrogen bonding present. There's some hydrogen bonding present because we're talking about a carboxylic acid here. And once again hydrogen bonding is a stronger intermolecular force than dipole dipole so it's harder to pull apart molecules of butanoic acid, therefore it takes more energy, it takes a higher temperature to pull these molecules apart to turn them into a gas. Once again, H-bonding is a stronger intermolecular force than dipole dipole. When we think about the solubility of an acid anhydride in water, once again it's kind of difficult. Something like acetic anhydride is going to react with the water. Acetic anhydride is also fairly reactive. Not quite as reactive as an acyl halide but it does react with water, so we can't really say that it dissolves very well in it. We'll talk much more about the reactivity of these carboxylic acid derivatives in a later video.