CHM 121 LECTURE - FRIDAY

[00:01:13]Good morning.

[00:01:14]Um it's 8:10.

[00:01:18]And there are barely 25 of you here.

[00:01:24]I don't think we can wait any longer.

[00:01:27]So, we're just going to kick ahead.

[00:01:32]Thanks.

[00:01:34]Is that it for Fridays?

[00:01:38]Many of us don't come to school.

[00:01:40]And then it's raining.

[00:01:43]Anyway, um we're going to round up carboxylic acids today. If you have any questions, please put it in the Q and A.

[00:01:54]Uh we started our discussion on carboxylic acids on Monday.

[00:02:02]I hope you enjoyed the public lecture.

[00:02:09]At least, I think that gives some of you perspective as to what you might be doing with the chemistry you're studying.

[00:02:22]So, today we're going to go discussion of carboxylic acids by looking at uh Good morning, Hassan.

[00:02:41]By looking at um I just want to see if there's anything Nothing in the Q&A already. Okay.

[00:02:58]So, physical properties of carboxylic acids.

[00:03:06]Now, we've been looking at compounds. We started from hydrocarbons. Now, we're talking about carboxylic acids.

[00:03:13]You probably would have noticed that or maybe now carboxylic acid will be the most polar that we have come across so far.

[00:03:25]It has a carbon carbon I mean, it has a carbon oxygen double bond.

[00:03:32]It has a carbon oxygen single bond.

[00:03:35]Then, it has an oxygen hydrogen bond.

[00:03:42]All these things contribute to polarity.

[00:03:47]So, carboxylic acids can form hydrogen bond.

[00:03:55]They can undergo hydrogen bonding.

[00:04:00]Just like alcohols and aldehydes.

[00:04:09]But the main thing that distinguishes carboxylic acids from the others is that they can form intra intermolecular hydrogen bonds.

[00:04:34]Okay, that's um intra is when it forms within the same molecule.

[00:04:42]Inter is when it forms between two molecules.

[00:04:50]And like we noticed with alcohol when comparing them to their equivalent homologous series they show higher melting points when they are solid or boiling points when they are liquid.

[00:05:07]So carboxylic acids are more stable in water than alcohols ethers, aldehydes and ketones because of their stronger hydrogen bonding.

[00:05:20]Liquid carboxylic acids have sharp and disagreeable odors.

[00:05:27]They also have sour taste.

[00:05:31]Okay, those are physical properties that you can look at.

[00:05:36]Now, I mentioned it last that carboxylic acids are so because they can produce ionizable hydrogen.

[00:05:48]And you look at the equation there generally. You have RCOOH, which is what we use to represent carboxylic acids.

[00:05:57]In water, it will give you RCOO- You can have the hydronium ion, or you can write it as RCOO- plus H+ And notice this arrow that goes in two directions, reversible.

[00:06:25]Okay, that's the equilibrium arrow.

[00:06:27]Showing you that the reaction can happen both in the forward direction and in the backward direction.

[00:06:38]So, that second there equation that I just put, if you're if you choose to write it, you remove the water.

[00:06:57]Okay?

[00:06:58]But if you add the water, then your product will be H3O+ This is the equation for determining pKa.

[00:07:13]pKa is um simply put, the degree of alkalinity or acidity. In this case, it's acidity for pKa.

[00:07:29]Alkalinity or basicity is pKb.

[00:07:33]You probably come across more of that in physical chemistry.

[00:07:44]>> So, you can look at this to help you appreciate why carboxylic acids are so acidic compared to other organic compounds.

[00:07:57]But, I'm sure you know that compared to mineral acids carboxylic acids are weak. Mineral acids are the acids that you're already used to.

[00:08:07]The inorganic acids like hydrochloric acid, sulfuric acid, nitric acid.

[00:08:14]They're called mineral acids.

[00:08:17]And compared to organic acids, those are the acids we're calling carboxylic acids here.

[00:08:23]Compare mineral acids to carboxylic acids, carboxylic acids are weak.

[00:08:30]But, if you're looking at only carboxylic acids or only organic acids then carboxylic acids are obviously the most acidic of organic compounds.

[00:08:51]And then you know that uh other compounds can also exhibit acid acidity in some cases.

[00:09:05]Uh alkynes You dealt with that under hydrocarbons, carbon-carbon triple bonds.

[00:09:15]Under certain circumstances, they can generate protons. So, they can be acidic in some cases.

[00:09:25]But, whenever you talk acid, you're mainly talking about carboxylic acids.

[00:09:34]Okay, so here you have an example.

[00:09:37]Can you tell us run off of an uh carboxylic acid. Here, ethanoic acid or acetic acid depending on whether you're using the IUPAC name or the common name.

[00:10:01]Okay?

[00:10:02]You see it can ionize to there's a minus on this oxygen.

[00:10:15]Minus on this oxygen.

[00:10:20]And then you can see it can resonate between two structures.

[00:10:29]This one and this one.

[00:10:36]Now, what this structure does not show are the arrows, which you should always show.

[00:10:43]So, this negative sign here, if it moves to this double bond, this one moves here.

[00:10:48]And that's why you know that that negative sign now comes there.

[00:10:52]And this is now double bond. And that's why you have this. So, this is more stable because it can form at least two structures.

[00:11:01]Okay, two resonance structures, if you like.

[00:11:06]Now, obviously, H+ has been omitted in all of these. Plus H+.

[00:11:13]That's what gives it its acidity.

[00:11:19]Okay? This is carboxylic acid. Now, compare it to an alcohol.

[00:11:27]You can see that the alcohol can also generate a proton.

[00:11:36]So, it can be acidic in an aqueous medium.

[00:11:40]Or you can see just this.

[00:11:44]If you were to break this up, you're just going to have uh C 1 2 3 H H H C H H O minus.

[00:12:07]You can see there's no double bond anywhere for pi electrons to shift. So, this one has just like this.

[00:12:15]While this one has at least two structures. So, this is more stable and therefore more acidic.

[00:12:26]Because these structures can always stabilize this. And so long as this is in the system, the system will be acidic.

[00:12:40]And then again, even to a much lesser extent, you can have again, if we use here, 1 2 3 C H H You can have under the appropriate condition that this becomes C triple bond C H here.

[00:13:15]C minus plus H plus.

[00:13:23]Once a compound can generate H plus.

[00:13:28]It can have a pKa value.

[00:13:33]And can therefore be acidic.

[00:13:37]Okay, this just going back to some of the things you've learned. Now, this is more difficult for ether, for instance.

[00:13:50]Let's take the same equivalent of the ether.

[00:13:59]Even if this breaks here, it is only going to give you this.

[00:14:05]It can never give you H plus.

[00:14:13]Okay.

[00:14:15]That's why that cannot be acidic.

[00:14:17]And you can look at the other ones. Once you cannot write an equation like that, if it's confusing you you're trying to find out which is acidic or not.

[00:14:25]Once you cannot write down an equation with the compound generating H plus, then it cannot be acidic.

[00:14:41]Those all these is to explain to you why carboxylic acids show the the nature of acidity they show.

[00:14:54]And then so you can therefore read all this.

[00:14:58]Now, I want to draw your attention to this.

[00:15:03]Uh if we if we draw this out, say R C O O O H.

[00:15:23]Okay, and you know it's going to break up, so let's just put it here as O minus H plus.

[00:15:36]Okay?

[00:15:41]The groups that are attached, if you remove this R and say you substitute with H CH3 you get your acetic acid.

[00:16:00]Okay?

[00:16:03]Now assuming you have you remove this H and you substitute with a Cl3 I mean a Cl.

[00:16:20]So now instead of having CH3, you now have CH2Cl.

[00:16:28]What happens is that because chlorine is a highly electronegative, it will be pulling electrons inductively from this carbon.

[00:16:39]So you know that there is a shared chlorine and Let me use another one.

[00:16:52]Chlorine and carbon are sharing electrons because it's a equivalent bond.

[00:17:01]Ideally the the two electrons they are sharing is supposed to be midway between the two nuclei.

[00:17:08]Okay? But because chlorine is more electronegative it has more protons in the nucleus.

[00:17:21]It's going to be more powerful and attract the shared electrons closer to itself.

[00:17:27]Okay, so quantum mechanically speaking, you will say that the >> [clears throat] >> the probability of finding the shared electrons closer to the orbital or closer to the nucleus of the chlorine atom is higher.

[00:17:52]So, inductively the electrons are being pulled towards Now, as the electrons are pulled the electron here, too, between this carbon and this carbon is also being pulled.

[00:18:18]And the electrons between this oxygen and this carbon is being pulled.

[00:18:28]The bond that was here if that bond was still there, it would be pulled.

[00:18:37]So, there are two ways of looking at it.

[00:18:39]Either that because this chlorine is pulling his electron with the drawing and it's pulling.

[00:18:46]When this hydrogen goes off let me put it in the numbers. Let me see whether this will help you understand.

[00:18:54]Assuming that when hydrogen was here that the pull of this oxygen on this hydrogen is two.

[00:19:10]If you now remove that hydrogen and put chlorine, chlorine has a higher pull.

[00:19:17]So, let's say the pull now, instead of two, now becomes five.

[00:19:25]Okay? Now it becomes five. Five is higher than two.

[00:19:29]So, that means that this hydrogen when it's going off, assuming that there was a way of quantifying it, it will be more positive when there's chlorine here, because chlorine is pulling at five, than when there is hydrogen, because hydrogen is pulling at two.

[00:19:55]So, the hydrogen that goes off when there's a chlorine there, is going to be more positive, if you if you permit the expression, than when it was hydrogen, because chlorine I say hydrogen would have taken away and left would have taken all the electrons and left some behind, chlorine will come and take more.

[00:20:27]So, the hydrogen will be more positive.

[00:20:29]And the more positive the hydrogen is, the stronger the acidity.

[00:20:36]Because remember acidity is measured by the negative log of the uh concentration of the proton.

[00:20:50]Okay? So, what all this roundabout issue is the issue that I'm saying is getting to is that when you have electron withdrawing groups on the alpha carbon, Sorry, on the Yes, well, alpha carbon, but I don't know if you remember that we did that.

[00:21:14]So, that is the alpha carbon or the carbon that is adjacent to the functional group.

[00:21:26]If you have an electron withdrawing group on it, the more electron withdrawing groups you have on that carbon, the more acidic that compound is going to be.

[00:21:38]If you have an electron donating group, electron will not donating group will donate.

[00:21:44]So, it will be a plus inductive effect.

[00:21:48]So, it will donate rather than remove.

[00:21:50]So, as it's donating, again, it means that when this proton goes off, it is not going to be as positive. The charge won't be as positive because electrons are coming in.

[00:22:04]So, when the electron donating group was not there, if the proton was going to go away with, let's say, a magnitude of positivity of two, when the electron donating group comes in, it's not going to put more electrons, so the positivity or the positive nature of the hydrogen will reduce.

[00:22:32]So, the implication of this is that if you have electron donating groups on the carbon that is adjacent the COOH, you are going to decrease the acidity of the compound that is producing the hydrogen ion.

[00:22:56]Okay, so if you take that explanation, you will look at If you look at [clears throat] this, for instance, this example that I give here.

[00:23:18]Where is that? Where is the example?

[00:23:34]Okay, this two bullet points. So, if you if you put a chloro, a bromo, or a fluoro a fluoro, rather.

[00:23:44]They are electron-withdrawing, okay?

[00:23:47]So, I think at this stage you should be happy with those examples for the time being.

[00:23:53]When you go higher, you get more examples.

[00:23:56]So, halogens, as I'm sure you are, were generally are electron-withdrawing by inductive effect, okay?

[00:24:04]So, if you add any halogen to any carboxylic acid, compared to the carboxylic acid without that halogen that halogen that has I mean, that carboxylic acid that has a halogen will be a stronger acid than the same carboxylic acid without the halogen.

[00:24:24]Conversely, if you are adding OH or NH2 to a carboxylic acid you are reducing the acidity of that carboxylic acid.

[00:24:48]And then, again, because inductive effect is affected by distance, the closer that electron-withdrawing group or electron-donating group is to the functional group, the COOH, the stronger the effect it's going to have.

[00:25:10]Okay, these are the first things that you can be examined on. So, please try and understand them.

[00:25:16]Now, let's quickly look at methods of preparation.

[00:25:21]There are several ways.

[00:25:23]Um So, most of these you're going to have to look at on your own.

[00:25:29]Oxidation of primary alcohols and aldehydes. We've seen those things when we talked about alcohols and aldehydes.

[00:25:38]If you're oxidizing alcohol to uh to carboxylic acids, it can go in two steps. It can first of all, if the alcohol is primary alcohol, it will first of all form an aldehyde, then it forms a carboxylic acid in two steps.

[00:25:55]If the alcohol is secondary, it will first of all form a ketone, then depending on the oxidizing agent, it can form carboxylic acid.

[00:26:09]But, remember from our oxidation of ketones, that ketones when oxidized usually form two carboxylic acids because the bond will break where you have the carbonyl and give you two carboxylic acids.

[00:26:30]So, you can just use that to revise.

[00:26:33]But, that's how you can form carboxylic acids either from oxidizing alcohols or from oxidizing aldehydes, okay? Because when you oxidize ketones, you're are still going to get carboxylic acids, but now you are getting two instead of one.

[00:26:59]So, please note the difference.

[00:27:06]So, here you have examples of general equation for alcohol and then a specific example, which I'm sure you will look at later.

[00:27:20]You can also prepare carboxylic acids from oxidizing alkenes, carbon-carbon double bond.

[00:27:30]Again, you would have come across this when you are dealing with hydrocarbons.

[00:27:34]So, this is more like revision.

[00:27:36]So, a lot of these things we are not going to dwell on because you have seen and like I said to you, methods of preparation of any compound, if you flip it, if you turn it around, you will get the reactions of that compound.

[00:27:52]So, like these things we are dealing with now, the methods of preparing carboxylic acids, we came across them under reactions of like in this first one, reactions of alcohols, reactions of aldehydes.

[00:28:09]This one, reactions of alkenes.

[00:28:13]So, so when you are reading this, it's also a good a good way of refreshing your memory on the previous things you've done.

[00:28:22]So, oxidation of alkenes, carbon-carbon double bond.

[00:28:31]You can also hydrolyze nitriles.

[00:28:34]Nitriles are those compounds that have CN.

[00:28:38]You can see carbon triple bond nitrogen.

[00:28:42]With uh we we haven't dealt with them as a group.

[00:28:46]Okay?

[00:28:48]Not at this level, but at least just like you know that alcohol is ROH, you should also know that nitriles are R CN.

[00:29:03]They are called nitriles.

[00:29:06]They've come across a couple of them.

[00:29:09]So, you can hydrolyze nitriles, acid hydrolysis.

[00:29:16]It will give you Remember we've talked about hydrolysis.

[00:29:20]You're adding water to break up the bond.

[00:29:30]While hydration is you're adding water across the bonds.

[00:29:37]So, if you look at this, your water molecule will break the nitrile.

[00:29:47]Break it here.

[00:29:52]In a manner of speaking.

[00:29:57]Okay? So, that this stays on this side.

[00:30:06]Then this one picks up four hydrogen atoms.

[00:30:15]There should be a charge here.

[00:30:18]Um Where is my There should be a charge on top of this.

[00:30:29]Cuz this is ammonium.

[00:30:32]Okay.

[00:30:40]So, nitriles, you can either have acidic hydrolysis represented by H plus or you can have basic hydrolysis represented by OH minus.

[00:30:58]Okay? What this basically means is that apart from dissolving the the compound in water, you have to either add an acid, maybe HCL or sulfate.

[00:31:14]In which case, if you had add that HCL, it'd have formed the counter ion here of C minus.

[00:31:24]Okay? So, that would be acid hydrolysis or basic hydrolysis where you use something like sodium hydroxide.

[00:31:37]Again, here the counter ion would be uh This will now become four and then the counter ion would be OH minus.

[00:31:59]If you look at the equation, you should be able to appreciate how it balances.

[00:32:07]Okay?

[00:32:08]So, that is another way of preparing carboxylic acids.

[00:32:16]We are going to look at esters when we talk about carboxylic acid derivatives where we will learn that esters are basically alcohols where the H is replaced with another alkyl group.

[00:32:34]Okay? In a way, you can say Remember alcohols? When you replace the H in the alcohol, you have an ether.

[00:32:43]E T H E R.

[00:32:47]But carboxylic acids, when you replace the H in carboxylic acids, you get an ester.

[00:32:56]E S T H E R.

[00:33:00]Another one, if you like, when you replace the H in aldehydes with R, you get ketone.

[00:33:10]So, maybe those those things can help you remember all that.

[00:33:15]So, hydrolysis of We've already said what hydrolysis is.

[00:33:21]Okay?

[00:33:22]It involves water.

[00:33:25]With acid or water with base.

[00:33:29]So, here now you're seeing base hydrolysis.

[00:33:36]of an ester.

[00:33:38]This is an ester.

[00:33:42]We're going to learn more about it.

[00:33:44]You can see that here, if you take this as If you take this as R, CH3, then this CH 2, I mean C2H 5, which is CH2CH3, will be the R prime.

[00:34:05]So, that's the ester.

[00:34:07]So, to hydrolyze it with sodium hydroxide, this will go off and to be replaced by H.

[00:34:16]And that's how you get your carboxylic acid.

[00:34:21]So, that's how you can say you're preparing.

[00:34:31]Okay? That's the equation.

[00:34:33]So, you see the first step it knocks off the C2H5 and puts So, if you were to break this down, you will have a minus on top of the oxygen and a plus on top of the Na, the sodium.

[00:34:51]And you can see here that the C2H5 from there has been taken off.

[00:34:58]And the OH comes here.

[00:35:02]Okay?

[00:35:05]So, again, if you if you assume Why is this hydrolysis? If you assume that this is water, and you know we said that hydrolysis it breaks the water breaks into two and breaks the compound into two.

[00:35:20]So, for base, this is breaking into sodium plus and OH minus.

[00:35:28]The Na plus will go to one side, the OH minus will go to the other side.

[00:35:33]So, you have two compounds there.

[00:35:37]So, that's why that is hydrolysis in this case.

[00:35:44]We'll call it basic hydrolysis.

[00:35:47]And then you now have the second step, which is called acidification.

[00:35:52]Acidification means you now introduce the H plus.

[00:35:58]By introducing acid, the acid will provide the H plus.

[00:36:02]The H plus will now go and knock off the Na plus.

[00:36:08]And now form the acid. While the Na that is knocked off will now react with the Cl minus that came from the H. And then you have your NaCl.

[00:36:22]No matter is created, no matter is destroyed.

[00:36:26]Energy is conserved.

[00:36:30]So, that's how you prepare carboxylic acids from esters. We came across Grignard reagents when we're talking about alcohols.

[00:36:39]They can also be used to prepare carboxylic acids.

[00:36:44]So, here the first equation is to prepare the Grignard reagent itself. You react an alkyl halide with magnesium in the presence of anhydrous ether.

[00:36:57]Anhydrous means the water has been removed.

[00:37:00]Because water will affect If there's water in this reaction, the RMGX will not form.

[00:37:09]If there's H2O anywhere around here, this will not form. Instead, what you'll be getting will be RMGOH.

[00:37:17]Okay? So, to make sure that that does not happen, you eliminate water.

[00:37:22]That's why you use anhydrous ether.

[00:37:27]Okay? Specifically, diethyl ether.

[00:37:30]Type of ether which you you've come across.

[00:37:35]So, you after the you form the Grignard reagent, you now carbo- carboxylate it or you add carbon dioxide.

[00:37:48]That will now give you this.

[00:37:52]So, the CO 2 goes and inserts between the R and the MG.

[00:38:03]Okay?

[00:38:05]You can actually write a simple mechanism for that.

[00:38:11]Okay, but don't worry your head about that.

[00:38:14]So, then when it gives you your OMGX here, you now acidify again.

[00:38:27]Now, when you do organic synthesis, where you make some of these compounds, this step usually do it in what we call the workup step. But, don't worry.

[00:38:36]That's still ahead.

[00:38:38]Anyway, so here you acidify or you subject it to acid hydrolysis, however you want to describe it.

[00:38:45]But, the the basic thing you're taking away from here is that this is going off.

[00:38:58]This will go off as Mg X plus because magnesium is electro- negative. Okay? So, it will leave this O as minus. Then that O as minus will pick up H plus and they will form here, instead of O Mg X, you now have OH, which is your acid.

[00:39:33]So, you see that in producing in preparing carboxylic acids from Grignard, it involves three steps. First of all, you prepare the Grignard reagent.

[00:39:46]Then you add carbon dioxide.

[00:39:49]Then you acidify.

[00:39:52]Okay? And here is an example with ethyl bromide, which is an alkyl halide, plus magnesium.

[00:39:59]Okay? You get your ethyl magnesium bromide.

[00:40:05]Okay?

[00:40:06]Carbon dioxide and then you get your propanoic acid.

[00:40:13]So, you can see that in preparing carboxylic acids from from Grignard reagent.

[00:40:23]You can note mentally that whatever number of carbon atoms you start in the alkyl halide, you're going to produce an acid that has one carbon atom extra. So, if you are starting with n is equal to two, you're going to end up with n is equal to three in the acid. If you start with [clears throat] n is equal to four in the alkyl halide, you're going to end up with n is equal to five in the carboxylic acid.

[00:40:55]And so on and so forth.

[00:40:57]This is when you prepare carboxylic acid from Grignard reagent.

[00:41:08]You've done this, you've come across this carbon-carbon double bond.

[00:41:14]If you carboxylate it, that is you add carbon monoxide and then water, you are in the presence of phosphoric acid at 400°.

[00:41:28]You are going to get carboxylic acid. This is more of an industrial way of preparing carboxylic acids.

[00:41:36]So, that's industrial. You can look at that.

[00:41:40]You can also prepare from malonic esters.

[00:41:45]Okay, these are diesters.

[00:41:49]Okay, they have They They These ones will form dicarboxylic acids.

[00:41:55]Okay?

[00:41:59]So, if you look again, you start with an alkyl halide with the malonate, sodium halide will be given off.

[00:42:11]And then you have You see The carbon that has the so the sodium Will be the negatively charged.

[00:42:25]So it will be the one that will attack the R whatever is here because the X will go off with the charge.

[00:42:34]So here if you are looking at the mechanism quickly this R will be the one that has the plus.

[00:42:39]This X will have minus. Between this and this the NA will have the plus the carbon will have the minus. So the minus of the carbon will attack The R And that's how they form that bond right?

[00:42:55]Then if you do Acid hydrolysis you get your dicarboxylic acid.

[00:43:04]So this one is for producing Dicarboxylic acids.

[00:43:10]Okay?

[00:43:13]Then If you don't want it to be die you decarboxylate By removing Usually heat. Once you heat heat is usually enough To remove the CO O and leave H there.

[00:43:30]And then that's how you get your Carboxylic acid.

[00:43:37]Okay? So here If you start with the malonate the ester You are going to get an acid that is one carbon atom less.

[00:43:52]Please note these things because these are the kind of things you can be tested on.

[00:43:56]So you start with the Uh The malonate It has three carbon atoms at least here now.

[00:44:10]You see that at the end of the day, you produce a compound that has one carbon atom less in the malonates.

[00:44:22]Then depending on what your alkyl halide is, the number of carbon atoms that it's bringing is what will be retained there.

[00:44:32]So, those are the methods of preparation.

[00:44:35]Let's look at some chemical properties, which in a way is also the reactions.

[00:44:42]We've already said that it's acidic.

[00:44:48]And then I already explained to you that if you have electron-withdrawing group, it's going to make the acid stronger.

[00:44:59]So, that is the table you are seeing there.

[00:45:01]If you remember that explanation, look at that table, it will make sense to you.

[00:45:07]Remember we call it an acid. From secondary school, we learned about acids and bases.

[00:45:13]Okay? So, here also, these acids can react with bases.

[00:45:20]Here you have two examples, sodium hydroxide and ammonia. They are basic.

[00:45:25]Okay? And this one will give you what you call organic salts.

[00:45:30]Okay?

[00:45:32]Just like in secondary school, we learned acid plus base will give you salt and water.

[00:45:37]Here also, acid and base will give you salt and water.

[00:45:41]The salt is the organic salt.

[00:45:46]You know, it's like the salt you you know in secondary school, except that now it has organic components to it.

[00:45:56]Okay? Same here.

[00:45:58]Here you can see the water is produced.

[00:46:01]Here also, if you want water, all need to do is add it and balance the equation.

[00:46:08]Okay? So, carboxylic acids will react with bases to give you organic salts and water. So, that means they can also undergo condensation reactions, if you like.

[00:46:25]Carboxylic acids can be reduced.

[00:46:29]So, you can reduce carboxylic acids to carboniles.

[00:46:34]You can also reduce them to alcohols.

[00:46:40]Then, you can also reduce them to hydrocarbons.

[00:46:45]Okay?

[00:46:46]Remember, reduction is the addition of hydrogen or removal of oxygen.

[00:46:56]So, let's look at this equation.

[00:47:00]You see that using lithium aluminum hydride, ether and water, you can convert a carboxylic acid to a primary alcohol.

[00:47:14]Okay?

[00:47:15]Note that.

[00:47:18]Carboxylic acid with lithium aluminum hydride will go to a primary alcohol.

[00:47:28]Not a secondary one.

[00:47:30]A primary one.

[00:47:37]Fischer esterification.

[00:47:40]This is where you form an ester.

[00:47:44]You form an ester by reacting carboxylic acid with an alcohol.

[00:47:50]Okay?

[00:47:51]So, here you see the example.

[00:47:54]We're going to see more of this in the next class when we talk about carboxylic acid derivatives.

[00:48:01]Decarboxylation is removal of the carbonyl group of carbon dioxide.

[00:48:08]So, that's another reaction.

[00:48:10]So, if you remove the carbon dioxide in carboxylic acid, you're going to get a hydrocarbon.

[00:48:19]Represented as RH.

[00:48:21]If you come across that.

[00:48:24]Uh reactions, we have only 3 minutes.

[00:48:29]Though we started late.

[00:48:32]Uh so, reactions, you will find that again, the metals of preparation you switch it over.

[00:48:41]So, you can look at all these. Salt formation you have already seen that as part of what we looked at just now. So, here you see as an acid it can react with base to form salt. And you've seen different kinds of bases here.

[00:48:59]So, anytime you see a base in the presence of acid is going to give you a salt, organic salt.

[00:49:10]That's the equation there.

[00:49:13]Acyl halides, we're going to talk more about that under derivatives. So, maybe after that you come and look at this. So, this this equations are how you form uh carboxylic acid derivatives.

[00:49:36]So, maybe we'll talk about them maybe for like 5 minutes.

[00:49:49]If If get a chance to look at them because most of those reactions we're going to be repeating in our class on Monday.

[00:49:59]This one is a table.

[00:50:01]You can have a look at it.

[00:50:04]Uh Yeah, we still have 1 minute, so you're going to see some of this in the next class.

[00:50:16]So, maybe if you take time to look at this, so that you'll be able to Acyl halides are carboxylic acid derivatives.

[00:50:30]So, any questions?

[00:50:38]Any questions? Any questions? Any questions? Where are the Where are the Q&A?

[00:50:46]There is no question there.

[00:50:50]Okay.

[00:50:54]Okay. So, you're going to get the slides and the recording.

[00:51:05]Make sure you look at Where did that one come from?

[00:51:12]I did not touch.

[00:51:16]Make sure you look at this last section of reactions of carboxylic acids because it will help you understand Monday's class, where we're going to be talking about derivatives of carboxylic acids.

[00:51:35]Okay.

[00:51:37]Have a good morning.