Transcript for:
Carboxylic Acids and Derivatives

[Music] [Music] hello my name is Chris Harris and I'm from honoré chemistry and welcome to this video on carboxylic acids and derivatives now this video is dedicated to AQA so none of this information here is generic information it is actually designed around the specification for AQA so if you are studying a level chemistry for this example then this is perfect view because it contains all the information you need to know and nothing more also there's a full range of these types of videos these are revision videos on a Lurie chemistry YouTube channel so if we just go and have a look there's a full range from year 1 all the way through to year 2 so it's a quite comprehensive range there's also some whiteboard tutorials as well on on the channel which will go through specific parts of chemistry so it's not specific to any part of exam board so it's just there for your information if you want to look at the specific type and also there's information on there about exam technique so we'll do some example walkthroughs and all of that is for free so all I ask is you hit the subscribe button and to show your support and to get any updates that be absolutely fantastic that'll be brilliant and the also these slides here my mind went a little bit blank there and these slides here are also available to purchase if you if you would like a copy of them and so if you click on the link in the description box you can get a hold of them there but they are great value for money because you can use them on the move your tablet smartphone and you know and scroll through them at your leisure also I know people who've who've got them and they print them off and they use it spot their revision notes they annotate them etc so click on the link the full range is there for year 1 and 2 everything is there ok so like I say this is dedicated to a QA and it meets these specification points so it's split up into two main types the first type being carboxylic acids and esters so it's going to start by looking at carboxylic acids and esters and then we're going to be looking at a solution reaction as well so looking at acid chlorides then looking at things like biodiesel and fat some vegetal oil and then finally looking at some practical techniques so that's the kind of running order for this video okay so we're going to start by looking at carboxylic acids so carboxylic acids and have this carboxyl group that's a C oo H group okay very important it contains both the carbonyl group which is the C double bond o and the hydroxyl group o H now you might have seen carboxylic acids in year one you might have seen bits of them there and this topic is really going to go into a lot of detail about carboxylic acids and look at esters and all the derivatives derivatives obviously just anything that spawned from carboxylic acids excuse me so they are named by finding the longest carbon chain just like you would do with any other groups such as a aldehyde or a ketone or an alcohol or anything like that we find the longest carbon chain and we end it with a weak acid on the end okay so when we're naming carboxylic acids the carboxyl group is always carbon one so that makes it nice and easy nice and straightforward and the carboxyl group must also be at the end of the molecule you can't have a carboxyl group midway through the molecule so it's always at the end it's always a terminus functional group so let's have a look at an example here so we've got ethanoic acid is the first one see it's got two carbons there and your carboxyl group is obviously at the end there it is there's your carboxyl group okay and obviously this is ethanol because you've got two carbons so it's eath for two just to complicate it a little bit more we've got this one now this is just to kind of show you how this carbon one works remember it's always carbon one so you can see here this is carbon one that's two and that's three so on carbon three you've got hydroxy on there and in carbon four you've got plural so it's always numbered from carbon one and your carboxylic acids always at the end so this one's for chloro three hydroxy butanoic acid and you can also get aromatic ones as well so this is benzoic acid so you can say you've got a benzene there with a carboxylic acid group or a carboxyl group right at the end there so you can see there's a variety of different types of carboxylic acid so you've got obviously the ones with some groups coming off it on the main carbon chain you got straightforward ones and you've got aromatic one so just as long as you aware of the naming of it and the carboxyl group is always carbon one that's the main thing okay so carboxylic acids are actually weak acids as the name suggests their acids obviously so they're weak acids and they react with carbonates to form carbon dioxide so they behave in exactly the same way as other acids would so acids plus base give salt thus water acid plus carbonate give salts as water plus carbon dioxide there's no difference here between any other asset so there's nothing significantly new so they are weak so it means they dissociate quite poorly now if you remember from the acid-base topic if you've gone through that then that's fine I've done a video on that if you haven't looking at acid-base topic but you'll know that with weak acids they dissociate weakly okay so in other words they don't dissociate but they don't dissociate follow so they don't produce many H+ ions equilibrium lies well over to the left as you can see in this diagram here so you've got your carboxylic acid in equilibrium with the carboxylate ion and the H+ ion so equilibrium lies well over to the left we've got loads of the carboxylic acid and we haven't got much of these at all okay so it's a equilibrium lies to the left so it dissociates poorly as we said so as the acids like say they react with carbonates and like any other acid would and they'll form salt carbon dioxide gas and water so let's have a look at an example so this is a wad with ethanoic acid reacting with sodium carbonate so you've got your ethanoic acid which is here there's your ethanoic acid sodium carbonate and obviously performing sodium with an array that's our salt plus water plus carbon dioxide on the right there okay so we've also got another reaction this is with sodium hydrogen carbonate and same type reaction still acid the base and that will form your salt plus water plus carbon dioxide it's just we're using hydrogen carbonate instead of just a carbonate okay so that's the kind of the basics the basic introduction to carboxylic acids so now what we're going to look at is what we can do with carboxylic acids so what reactions are they involved in and some of their derivatives from that okay so force first of all we're going to be than at the formation of esters okay all the core esterification so that's one one reaction that you really do need to know where we're reacting the carboxylic acids with an alcohol okay so we can react them with so reacting that alcohols with carboxylic acids and acid anhydride is you're going to see later on what they are these can be used to make esters because they have an esters have the C oh oh group of them okay you might have seen esters already you might have even seen them at GSA possibly depending on the spec that you've done but effectively they're made by reacting alcohol but the currently silica acid or it could be an anhydride as well acid anhydride so an ester they say is produced when reactive carboxylic acid with an alcohol and we use a sulfuric acid catalyst okay now if you've seen the transition metal topic you would say that sulfuric acid is a homogeneous catalyst so it's it's integrated within the within the actual reaction so it's always reformed though because that's a catalyst so an ester is also produced like they say when reacting acid anhydride reacts with an alcohol but we'll look at this later on because acid anhydride really falls into the derivative section which we'll look at towards the the middle to the end part of the video so let's have a look at the reaction here so you can see we've got a carboxylic acid and it's reacting with alcohol color coordinate so you can see what's going where so carboxylic acid atoms are in blue and your alcohols are in yellow so you can see here that we've got our carboxylic acid bit here now alcohol bit here so the hydrogen here and the O H basically drop off and they form your water molecule here so it's just showing you how it's all structured it is in equilibrium and we do have an acid catalyst obviously that's all sulfuric acid catalyst that we're using there okay same reaction happens with an hydrides as well so ana hydrides just to give you a brief introduction to what they are cause you do need to know about them eventually but ana hydrides are basically like carboxylic acids except instead of a h here we have it's bonded directly to a carbonyl group sort of seed or bond oh so it looks like a carboxylic acid that's like cut in half and there's a bit of symmetry with these as well so the only ones that you need to know for acid anhydride the symmetrical ones in other words the ones were the same number of carbons on the top as they are on the bottom okay so they're the ones which you'll be expected to name them you might see ones that might be asymmetric but the reaction is exactly the same we only expected to name the ones which are symmetrical okay so you got all as as expected and that will form your ester but instead of forming water we form carboxylic acid and again it's all been color-coded so you can see so you can see what's what's going where okay so um esters they are actually named in two ways okay well not two ways one way but they're in two sections okay so the first bit is named from the alcohol that was used and the second bit is named from the carboxylic acid so let's have a look at an example where we react in ethanol with propanoic acid okay so you can see this is the ester that we form here but we need to be able to name it so remember we're going to name it we'll kind of almost name it back to front okay so we name the alcohol bit first and then the carboxylic acid so the first bit this bit here so this part of the ester is formed from the alcohol and is the alkyl group so this is e style because it's got two carbons and is named first when we're naming an ester and obviously the second bit is this but here this is named from the carboxylic acid and all we do is remove the awake acid bit from the molecule from whatever we've got and we place it with oh wait so in this example it's propeller waiter okay and this is always named second when we name in Restless it's almost the alcohol bit in red then the carboxylic acid part in blue so the full name of this is ethyl propionate okay so if I'll be in the red bit per pound weight being the carboxylic acid bit so it's all been color-coded as you can see what's going on okay let's have a look at another example of naming and esters we're going to make this a little bit more complicated yeah we've put a methyl group in there so this is reacting ethanol the two methyl propanoic acid okay so when we name in esters okay what we have to do is with an alkyl branch is we number them from the see oh see part so that's this bit here okay so we always number it from here so that's carbon one two three and that carbon-12 so we never named it the other way so we always named it closest to this group here that's the first thing we should say so this part of the estep is formed from the alcohol ok so just as normal so this is your ether group and then this bit is formed from your carboxylic acids so this is two methyl propyl oh wait so this the methyl group is you can see sits on the second carbon so therefore it's called to meet Alpana right so the full name is simply ethyl two methyl propyl oh right okay so you can see how straightforward it is it's actually logical and structured I know you have to name it back to front in this case but you know as long as you know the rules you should be able to name any ester that you wear that you have in front to you okay so esters are used commercially in industrial processes okay so esters are actually really useful all over the place in terms of foods and perfumes and another reagents like that normally their custody numbers so so let's have a look at the first one the first example so it's perfumes and food flavorings so semester's have a sweet smell see if you've ever made esters at school or college then you'll know that they have a distinct smell some of them smell really really horrible and some smell like rancid sick or rancid butter and some of them smell nice like pear drops so that's a classic sign of an ester so it depends on what alcohol and what carboxylic acids you are reacting it with so this makes them ideal to be used in the perfume industry the fragrances and the food and food industries well so like I say in food industry they are clusters eeen umbers okay so they're also used in solvents as well so esters are polar and so will the polar compounds will dissolve readily in esters such as water for example and they have low boiling points they evaporate easily that's ideal for a glues for example so if you put glue on a surface you want it to be liquid and then over time you want the you know the solvent to evaporate and that leaves behind a hardened resin that effectively sticks something together so it's like like a solid solid product that's left behind so they are used a lot in glue and they're also used in plasticizers as well so this is where you want to make plastics more flexible during that polymerization period so for example you can see the rubber ducks in the background so they're quite soft and squidgy so you can squish them nuts because they have plasticizers in them you've got to be careful though with plasticizers and there is Sochi strict laws regarding this about regarding the use of plasticizers and plastics particularly in children's toys because children put especially younger children to put things in the mouths and if they've got a plasticizer in there that leaches out readily and is toxic then that isn't great so the strict standards that are that are set when development products particularly when this plasticizers involved but naturally over time plastics do become brittle you know they don't last they don't last a well some do last a long time obviously the degradation of of plastics is quite slow and sometimes they they really don't decompose that well but you know if you leave plastic out for a long period of time in the Sun and it's allowed to you know to break down using UV light coming from the Sun and then eventually the plastic will break up become brittle you may see this outdoors if you look at some of Maeby's plastic garden furniture or anything that's plastic outside you'll see the effects this can have particularly contains a plasticizer okay so we're going to look at ester hydrolysis now okay so we've looked at how you make an ester so you make an ester by using a carboxylic acid or acid anhydride and you route that with an alcohol so this is where okay we've made the ester but we want to break it down and want to break it into its current into the molecules that we use to make it in the first place and we call this hydrolysis now hydrolysis just means split with water so hydro meaning obviously water lysis meaning to break so hydrolysis means to break using water however it can be sped up using an acid so we could acid hydrolysis or a base I mean call that base hydrolysis so it's fairly straightforward we're gonna look at acid hydrolysis first so here we're going to use a dilute acid to split an ester into a carboxylic acid and and alcohol okay so basically it's just splitting this member it's splitting these two apart so we can use sulfuric acid or hydrochloric acid and all of this is conducted in the reflux and you'll see this towards the end of the video when we look at practical techniques reflux is used when you we're heating volatile liquids will want the benefit of the heat to allow them to work but we don't want our products or reactants in that case to just evaporate off into the atmosphere so reflux allows us to do that so is the first one this is your ester you can see here this ester is ethyl ethanoate and we're going to react it with water because it's hydrolysis but we're gonna have an acid catalyst in there hence the H+ now this is going to form two products as you've seen them already you know we form a carboxylic acid and alcohol but just to show you where it all comes from remember the red bit comes from the carboxylic acids now the O H to finish off the carboxylic acid comes from the water and then you've got your alcohol as well which is the blue bit and again the final hydrogen comes from the water molecule so we're just using acid here to help kind of catalyze this reaction okay to speed it up okay so still looking at still looking at ester hydrolysis we're going to look at base hydrolysis now so base hydrolysis is basically where we use a base to split an S that's exactly the same as what we've seen before so it's no different except we using the base the products are marginally marginally different cuz you form an ion but you form a carboxylate ion and an alcohol so we use the base that we use is sodium hydroxide them again it's all conduct conducted under reflux as as I've mentioned before for the same reasons so let's have a look here's our ester and this time as you can see we're reacting it with ROH minus reason to know it's minus sign here so it's our base hydrolysis and we form our carboxylate ion and we also form alcohol as well okay so just remember hydrolysis is hydro at lysis if you have this brick if you have to break it down or split it up so you can see hydro meaning water lysis just means to break so hydrolysis I mean separate use mortar but sometimes you it needs a bit of help from an acid and a base okay straight four words pretty much engaged just the reverse of esterification okay so we're going to start and look at a map so that's the first derivative that we looked at and that's an ester well it's kind of a derivative it's actually whether it is actually it's not a derivative is it so it's actually made from carboxylic acids and but this here is a derivative and it we're going to look at fats and oils so quite like this bit because it actually links together something which may look quite detached from from pill from from everyday life we're going to bring these esters and carboxylic acids together and we're going to actually look and see you know how do these esterification reactions you know translate themselves into everyday life and this is a classic example were look at fats and oils so when we react glycerol which is just a type of alcohol and fatty acid which is a type of carboxylic acid and we produce an ester which makes fats and oils okay so this is pretty cool notch it's a really good one later on where we look at how you make soap you might have done that in the lab and you know it's school or college but it's a it's a really good I like I like that practical it's probably one of the favored ones I think that and transition metals to be favorable if you seen any other videos you see I'm a big fan of transition metals nice and colorful okay so let's look at glycerol so glycerol is propane one two three trial okay so it's an alcohol but it's got 308 groups as a trial its reacted with long-chain fatty acids which can be saturated I they've got no double bonds at all or they could be unsaturated and that means they've got at least one double bond in them so you can get different types so glycerol that's all look at the formula for glycerol so glycerol as you can see is propane one two three trials so propane because you've got three carbons there and it's one two three trial because you've got two alcohols there okay so it is just a big alcohol that's all it is but don't when you look at that don't think oh that looks really different it has an O H group on it's just now qahal okay so we're just using the same methods that you've seen before we're just going to apply this okay so a saturated fatty acid looks like that it's massive okay so these have obviously the the ester I saw the carboxylic acid group the carboxyl group at the end but attached to this is you've got loads of carbons and a big long carbon chain attached to the siding we call this a saturated fatty acid because it contains no double bonds but if it did contain at least one double bond then this would be an unsaturated fatty acid okay so you can see that unsaturated fatty acids have more than one double bond or they can have more than one double bond these are called poly unsaturated fatty acids now you might have heard some of these terms before like saturated fats and unsaturated fats so you might seen these in food so your saturated fats are the worst types of fats so these are the ones which can increase the level of bad cholesterol in your blood and can lead to heart conditions and stroke so that you know your saturated fatty acids are normally found in deep fried deep fried food you know greasy food like that says say like cheese for example butter lard things like that particularly lard in particular that is just animal fat so and saturated fatty acids they're not good for you at all whereas if you need fats in your diet it's an important part of your diet but the fats that you should be having are things like unsaturated fats so these have some double bonds in there and these in saturated fats they normally found in things like nuts for example so nuts are rich in things like unsaturated oils or essential oils essential fatty acids as they call them so these are the good types of fats which you need which you need in your diet so these are the ones that you do need in your diet your saturated ones aren't so now you know the difference the reason why it's called saturated is because if you've got a double bond in there you'll have less hydrogen's so the word saturated is referring to the amount of hydrogens in the molecule per carbon so you can see if you've got loads of double bonds in there you haven't got as many hydrogen so it's unsaturated so that's where the word comes from so if you didn't know that you've learned something right so let's have a look at how we actually you know what we do when we react these together so when we react the glycerol as we've seen there and the fatty acids in the previous and the previous slides have seen them already we produce an ester and that makes fats and oils okay so these are the key things okay so there we are okay so an oil is an ester and an example is shown below and we can see the ester links so you can see here this is a type of oil okay so we've got our this is come from our alcohol okay so this is our glycerol and our carboxylic acid is here but when we join them together just like with any other reaction we form an ester except because we've got three sites where these can form we can form three different esters okay and you can see on there so these are this is an example of an oil ester okay so vegetable oils they have unsaturated hydrocarbon chains so that are not straight which means they can't pack together closely and hence have lower Vander Waals forces and they have lower melting points and are liquids at room temperature so you can see here if you notice if you notice here you've got some of these chains here where this double bond here is actually in a M now this is a trans setup because you've got down here and then it goes down okay whereas this one is a syst set up so you can see here there's your double bonds and it's on the same side seen see it like almost forms this bowl shape here and this one is a trance set up again so all these chains can be insist transistor ons all the way through and because of this they really can't pack closely together because they're kind of some of the chains are buckles and they can't form you see there's a bigger space there than there is here so the compact like they're tightly together so that means they're not really they've got low forces between them so that means they're more like to be a liquid at room temperature and they have lower melting points as well and boiling points for that matter okay so oils are set up like that now a fat is an ester and then examples shown below and we'll have a look here but notice the ester links again in the blue box is still an ester but notice the difference between this which is a fat and an oil make a vegetable oil so this is a fat Esther but you'd never think you'd describe an esters as fat esters but yes this is a an ester that it's described as a fat so animal fats are a classic example this and a mentioned large as well before but they have saturated hydrocarbon chain they're straight and uniform okay you can see there there's no we don't get any sis trans because we haven't got any double bond so we can't have sis trans or E's at isomerism should I say in these molecules so they they pack tightly together the Vall uniform the wall in line there's no difference in the spacing here and so therefore they have much more stronger Van der Waals forces between these chains and so therefore they're melting and boiling points are higher and so that means actually these types of esters are solid at room temperature and you can see here that lard is just the the fat that's all lard is is this white bit here and obviously lard can be used for cooking and baking etc and so it's a it's a type of fat but it's solid at room temperature because of this close packing of the chains and higher van der Waals forces so you are expected to differentiate there might give you a massive molecule like this don't be frightened by it all you're looking for is doesn't have double bonds in its like to be an oil okay if it has no double bonds in it's gonna be a fat and you just need to explain why but this is just using chemistry from year one when we're looking at Van der Waals forces and intermolecular bonds okay so we're gonna go from oils and fats and moving away from food and we're gonna look at this one this is what I was saying before we're going to look at making soap okay now you might have made this in the lab at school or college if you and obviously if you have access to a lab you might have done this it's a great reaction and it works it works really well quite often in chemistry reactions don't really work too well but this one really does and so animal fats and vegetable oils they can be hydrolyzed to remember we looked at this already there's nothing new here we're just applying it to we're looking at but just applying it to fats and oils instead but they can be hydrolyzed to remember that's breaking it up using water okay and we're heating them with sodium hydroxide and what we produce is soap okay so the example below uses an animal fat to make soap with this with this one but you can use oils as well but we're going to use an animal fat to do this so it's a saturated ester you can see we've got no double bonds in here this is just an alkane chain that's attached to it so it's definitely a fat and then what we're going to do is react that with sodium hydroxide okay so there so three three amounts of sodium hydroxide and what I've done is have color-coded these so you can see where the atoms are going because I think it's a bit complicated when you've got a lot of you've got a lot of carbons here so we're going to form glycerol so there's our alcohol that's back okay that's fine because it's hydrolysis but the key thing is we actually form a salt of the carboxylic acid so we form it effectively it's a sodium salt and that sodium salt is soap and we know it's a soap because actually we see it's definitely a solid because you've got a big long hydrocarbon chain but also when you think about it when you wash your hands you want the soap to kind of to disintegrate in your hands and get on to your hands so you can wash off any dirt that you've got on your hands so you can see here this is definitely a salt and this will you know break up when it's when it comes into contact with water but the integrity of the soap will remain most of it will remain because we've got this big long hydrocarbon chain so there are bonds that's holding it together so the whole thing doesn't disintegrate you know at once because I'd you'd have a bar soap and you only be at user once and that wouldn't be very good okay so that's how you make soap dead easy reaction really you mean you can you know you can you can do it at home essentially you know if you get this stuff but you've got to be really careful the sodium hydroxide because it's concentrated sodium hydroxide so you know it's really caustic and you really do you know you can't really you know handle up you've got a handle up basically carefully because if it gets in your eyes it can damage your eyes and damage your skin etc so you know it's probably best you know obviously doing this in a lab you know and with all the right equipment and protective equipment as well but yeah but when I say you could probably do it at home it's just because it's a simple reaction it's pretty straightforward you can get access to things like you know fats and oils quite quite readily okay so we're gonna look at another use for this which is biodiesel okay so biodiesel is a type of fuel and it's made from vegetable oils and it basically vegetable oils they can be converted into this biodiesel by reacting the oils with methanol and a potassium ion potassium hydroxide as a catalyst so a catalyst basically and so this is used to power cars and actually there are some companies that will take away old chip pan a walled lake from and fryers to deep fat fryers so in chip shops for example they'll take away the old oil and that actually converted into biodiesel so they'll get some use out of it instead of just been thrown away so biodiesel is just a mixture of fatty acids made from methyl esters and it can be made from rapeseed oil I could say rapeseed oil is the oil that's normally used in cooking oil so here's our oil here so what I've done is have just shortened it a bit the R group obviously represents your your hydrocarbon chain that's on the end here okay so we're then going to react that with some methanol we've got three molecules of methanol and we're going to use potassium hydroxide as our catalyst and then we form glycerol there's our glycerol there obviously we're going to form methyl ester this is our ester here now that ester is actually our biodiesel and that's what we're going to then use to obviously to power a car with sweet and C and all we're doing is reacting our ester with alcohol and reform so your oil which is which is an ester and we're gonna react up there with our alcohol and we're gonna form a methyl ester which is which is what we use to power things so you need to be able to you know write that down we call that in an exam and you need to know how we make biodiesel and what it's used for okay right so that's the end of that bit so now we're going to look at another derivative and this derivative is going to be acid chlorides or a style chlorides so these are quite funny you might have seen these again in science and the sorry in your lessons you might have seen these and school or in college likely these probably would have been done by by a teacher or lecturer because they are quite reactive reactions so it's all chlorides or not also known as acid chlorides they have the functional group cocl which contains the acyl group which is cocl okay now acyl chlorides are named by finding the longest carbon chain and then adding oil chloride at the end now you'll notice this is pretty much the same as a carboxylic acid okay so we're naming it in the same way we find the longest carbon chain and except instead of adding awake acid we had oil chloride on the end so when naming acyl chlorides the carbon on the acyl group is always carbon one again it's exactly the same as carboxylic acids and the acyl group will always be at the end of the molecule as well okay you're never going to find it in the middle of the molecule so let's have a look at an example so here we've got ethanol chloride so we've got two carbons on this exactly the same two carbons and it accepts you'll notice the main difference here the reason why it's a derivative of a carboxylic acid is because a carboxylic acid would have an O H group here but with an acyl chloride or an a cycloid you have a chlorine atom at the end here instead so very similar let's look at a more complicated example so this one you can see we're still numbering from the same place so this is carbon one so in carbon two we've got a methyl group so that's fine that's what we put there at carbon three we've got a hydroxyl group and carbon four we've got a hydroxyl group so this is going to be two three four dihydroxy two methyl chloride in case of that's how you would name that okay I'll miss an oil so I butanol chloride sorry methyl butyl chloride there we go the case because it's got four carbons there so it's definitely gonna be butanol chloride okay so we need to look at so now we know what a cell four words are and we know kind of how to name them as well what we need to know now is their reactions now there is and quite a few reactions with a so applauds as for and particularly you need to know and that's is that a cell close reacting with water reacting with ammonia reacting with alcohol and primary amine so in each reaction basically the generic view on it is that the chlorine is substitute for ease of an oxygen or nitrogen obviously depending on what you're reacting it with so let's look at all of these four we need to know all four reactions and we need to know what we're producing with each okay so we're going to start by looking at carboxylic acids first so and carboxylic acids we have our acid Cloyd as you can see there and we're going to react that with water and when we react ethanol chloride with water we produce a carboxylic acid in this case it's gonna be at the noahic acid plus HCl now you'll notice HCl is a hydrogen chloride gas okay it's a really toxic gas it's really acidic you really should be doing this type reaction in a fume cupboard you shouldn't be doing this out in the open air because you breathe that in it's really gonna irritate the lining of your lungs and also the reaction here is incredibly reactive the reason why it's reactive is we've got this strong Delta positive carbon here you know that the water can attack this Delta positive carbon the lone pair of electrons on the oxygen and attack that and that obviously substitutes or takes off removes the chlorine from there and obviously have yet alcohol a complex in the acid group here so this is incredibly vigorous reaction you know it's you really got to be very careful this very exothermic reduced a lot of heat obviously got this white misty fumes as well okay let's have a look at the same thing so we're going to react with ammonia instead so reaction with ammonia produces a mites so here's our acid chlorides ethanol chloride so we've got the two carbons there and this time we're going to react it with ammonia and so the same reaction again very vigorous reaction except we produce a name ID so an amide is where you've got a carbonyl group here and an NH 2 next to it so that's an amide don't confuse that with an a mean and a mean doesn't have this group here okay you've just got naming there and then obviously again we've produced white mister fumes highly highly acidic gotta do it in a fume cupboard okay and you can see it also color-coded these as well seat and see where the atoms are coming from because I think it helps a little bit okay so let's have a look at reaction with alcohol now these produce esters so there's our acid chloride we're going to react it with an alcohol and we promise that okay so it's acid chloride plus alcohol will form ester plus HCl so it's very similar to an esterification reaction so remember is a derivative of carboxylic acid except instead of producing water were producing HCl so it's a lot more lot more dangerous and the final one is reaction with primary amines now this produces n substituted a might well it's a bit of a mouthful let's look at C this is so you can see here we've got a phenyl chloride again we're using the same a cycloid and we're going to react that with a primary amine as you can see there and that's going to form our n substituted a might now all that means is that normally with an amide as you seen before you'd have NH 2 there but one of the hydrogen's has been substituted for a alkyl group as you can see here now the alkyl group in this case is methyl because we've started with methyl amine as you can see there so because this is this is substituted we say it's N and where the word substitute is we write down what group is substituted for the hydrogen so that's methyl in this case and then you just name the rest of it each danam ID so you've got two carbons soc phthalimide okay again same products are produced there okay so we've looked at them reaction as a cycloid very vigorous reactions we've got a carbon that's literally been stripped of its electrons by two electronegative elements from the oxygen and chlorine and but there is another type of reaction where we're using an acid anhydride instead so very similar reaction and what you need to know is the reactions again reacting them with water ammonia alcohol and primary amines but this time we're going to react it with an anhydride and so we've seen anhydride is just a little bit perform it seen one of the reaction examples so unhide rides just to go through what an anhydride is first and an hydrides are made from two carboxylic acids that are the same okay these are the only ones that you need to know for AQA so acid anhydride ZAR names by naming the no one sorry are named by knowing the carboxylic acid by naming the no one carboxylic acid it's made from and removing acid at the end and adding anhydride to the end okay so we'll remove the acid bit and put an hydride so here's an example here so there's our o and hydride our acid anhydride so what we're looking for is we're looking for the the type of carboxylic acid is now you can see what two carbons here and we have got two there now the wall is going to be a symmetrical and identical so we only look at one of them and name it from there so this one's going to be ethanoic anhydride as you can see there because this is the two carbons here so it's not butanoic anhydride and that may sound a little bit strange do you think we'll hang on you've got four carbons there because they are the same we just named one of them and we just say ethanoic anhydride okay so as long as you know that that's the main thing okay so again let's look at the reactions with water ammonia alcohol and primary amines now the reactions are very very similar to a cycloid so there's nothing new here it looks at those a lot of information here but there isn't it's just very similar the only difference is the products are slightly different okay we're still producing or similar type reactions but instead producing HCL we actually produce a carboxylic acid instead and so these are a lot safer to use but they are less vigorous they're nowhere near as reactive as acid chloride so that could pose a problem because they're a little bit slower if you are you know in the business of making some of these products so let's have a look at the first one we're going to take an anhydride and react with water now this produces carboxylic acids so there's our ethanoic anhydride we're going to react it with water and that's going to form ethanoic acid and also we're going to produce another molecule of ethanol gasses in this case as well so we're going to produce two of them but again I've color-coded it so you can see you know where the weather molecules are where the common form okay so the reaction with ammonia produces ear mites so here's your ethanoic anhydride again and we're going to react it with ammonia so you can see is very similar to acid chlorides so react with ammonia and we form a amide so this is an amide plus carboxylic acid so remember what I said is exactly the same as acid chlorides except instead of reducing HCL we're going to produce a carboxylic acid instead okay so again not too bad here's the next one so this is reaction with alcohol produces esters so here's our acid anhydride and we're going to react it with an alcohol and just like with acid Claude's we produce an ester there it is and we produce a carboxylic acid and then finally here's the other one which is reaction of primary amines produces n substituted a might so there's your ethanoic anhydride reacting with the primary amine this is going to form of Ziya and substituted a ride exactly the same plus carboxylic acid okay so you see there's a lot of symmetry with acid chlorides and acid anhydride so the reactions are the same it's just the obviously with acid anhydride you produce a carboxylic acid with acid chlorides you produce HCL instead okay so what we're going to do is we're going to look at some reactions regardless and this is going to be a nucleophilic addition elimination reactions so remember what we said about acid chlorides having that strong Delta positive on that carbon which is really susceptible to attack from nucleophiles so what we need to understand there's obviously the reactions that you've just seen but we also need to know the mechanism associated with that so this is what we're going to be looking at here so remember what we said was we've got a really strong Delta positive carbon there because you've got an oxygen the chlorine that's stripping the electrons away from that carbon or pulling them away and because they're really electronegative so you're going to have you don't just have one electronegative element you've got two there so what we're going to do is look at a mechanism for ethanol reacting with propane oil chloride okay in this example but it can be any any reaction or any any nucleophile layer such as you might obviously going to use alcohol here but it could be water it could be an amine or it could be an ammonia it could be any of the ones that you've seen but that mechanism is the same so here's our a cycloid and you can see that we've got methanol as our alcohol here we've got our symbols on here Delta negatives and Delta positives and the lone pairs so what's going to happen here is the lone pair on the and the methanol and the alcohol this is a nucleophile and so this is going to attack the Delta positive carbon on the acid chloride okay so with it being a nucleophile that's nucleus love and so it's going to itself has a lone pair of electrons it's going to attack that Delta positive carbon so then a pair of electrons from the double bond is then transferred to the oxygen so that breaks okay and so then what we're going to do is form this intermediate so this is the addition bit so we say nucleophilic as you can see there addition elimination so the addition bit is this we basically bolted on the alcohol group the whole lot and it's stuck on to the end of this group here but now we have two charges we have a negative and we have a positive so we've done the addition bit there so that's the whole thing that's added on clearly that's not very stable because you've got some charges on there okay so what's going to happen is the electrons from the oxygen there are going to reform the double bond again so you've only just broken it but it's going to reform it back again okay and so then what's going to happen is because then the carbon would then have five bonds one of the bonds is going to break and that's going to be the chlorine so that CCL bond is broken and so therefore up so you form your you form a you're not quite there with your products but you form an another intermediate okay so we've got a lot of arrows going is a lot lot going on in this mechanism so there's our intermediate that's what we've just formed there we've still got that positive charge on the oxygen however we have a chloride ion that's floating around that's floating around as well that's obviously just been removed from this molecule and so what happens is the lone pair on that chlorine and goes for the hydrogen on the O H group okay so we need to neutralize this positive charge so it goes for that and then the electrons in that bond then go into the oxygen to neutralize that positive charge okay so then we then finally form our product which is that and there's our ester so the mechanism that's probably one of the most complicated mechanisms you're going to see it a level there's a lot of lot going on there you need to remember that mechanism the obviously the reagents that we're using here was an alcohol but that can be applied like you say to any of the other three which is water ammonia and primary amines so you know the mechanism is the same so don't worry too much about that okay so just be aware of that loads of marks on offer there okay so the mechanism like to say it applies to the rest of them as I just said there so I've jumped ahead again okay so what we're now going to do is look at another type of reaction so this is using and we'd seen it already but using an aromatic a an aromatic compound here and we're gonna make aspirin okay so again you might have done this at school or college you might have made aspirin again it's pretty straightforward reaction it's a nice reaction you get a nice white powder that's produced from aspirin and so aspirin is an ester that's all it is is made by reactant ethanoic anhydride or ethanol chloride and salicylic acid and we've seen some of the salicylic acid already but here's our ethanoic anhydride and well we haven't seen salicylic acid but we've seen an aromatic compound so ethanoic anhydride and here's your salicylic acid here okay so again I've color-coded where things are going to go so we've got the blue the red and a blue farmer over here as well so that's salicylic acid and so that's going to produce this which is aspirin okay and again I've color-coded it so you can see the hydrogen from the OHS drops off and the red bit here from your anhydride adds on to the end here so this is obviously this is your your ester here this bit is your rest a bit this bit here and then obviously we're going to form ethanoic acid as well as a product as a byproduct so you can see here that ethanoic anhydride is used instead of ethanol chloride in industry can you think of the reasons why so remember what we said about acid collides and acid anhydride before well it's safer it's less corrosive acid curds are a really really nasty you know very corrosive chemicals you don't want to get them on your hands and the other one as well is that actually we're not producing HCl gas so if we used an acyl chloride instead of ethanoic anhydride then we'd get hit CL produced and that's not very good to produce and it's a lot cheaper as well so unhide risers are cheaper to use than acid chlorides and also it's safer it doesn't react vigorously with water that's the key thing acid chlorides do you know you've got to be you've got a really handle acid chlorides and with a lot of care but with your and hydrides here they're they're not as not as dangerous okay so you need to know that reaction as well so you can see there's a lot of different reactions here there really is you know a lot of ways in which you can you a carboxylic acid or its derivative to form loads of different products such as obviously an aspirin and we looked at how you make em soap as well and biodiesel and esters and you know all these other things there's loads of different things that were making us it's quite an interesting topic okay so we're going to look at the last the last few slides now so these last ones are really going to look at practical technique okay because all these things here that you see in organic chemistry and it's about making a product and such as aspirin such as biodiesel such as soap and things like this but what we need to do is make sure that we've got a pure product okay and there's ways in which we can make it and ways in which we can test to make sure it is pure so the first way which we've come across already is reflux now reflux is a technique if you want to heat volatile liquids remember that sort of said before so reflux allows us to heat these reactants really strongly but we can contain all of the reactants within the conical flask where you can contain it in there and we're not losing any to the to the environment so because they actually condense against the Liebig condenser so you can see here that when we heat our substance here it starts to boil it evaporates up here it hits the condenser and it drops it drops back down the condenser and into the flask again so and we have water coming in and we have water going out at the top here so we've got this outer layer here that's surrounded by cooling water so that allows our substance to condense against the side of the lyric condenser and then back down it allows us to heat things without losing our product now you'll notice that actually were heating this in a water bath so we're not heating it directly this is because normally for the chemicals were using under reflux and they are volatile as we said and they are flammable as well so if we put a naked flame right near a flammable liquid in that flask and I have seen it as well and where sometimes if this seal hasn't been sealed properly here and then you might get vapors of flammable gas coming out and if this flame licks up and starts you know captures one of these vapors coming off you can actually get a reflux condenser that's on fire and so you've got to be really careful with that okay another type is this so distillation is really used when we want to separate substances with different boiling points and again you might have seen this you might have seen this already in the lab so what we're doing with this list is we're gently heating the mixture and that will result in compounds separating out an order of boiling point so we heat it in here again we're using an ice or mantle here or water bath so we're using something not using the direct flame for the same reason as we mentioned before so knowing the boiling points of the chemical you want to separate will allow you to decide how you're going to separate your compound okay so if we know the boiling points of these we can heat it to that temperature so it works by it works in a simple way depending on what you want to pick up but if your compound has a lower boiling point then your starting mixture then you heat to the temperature to the boiling point the compound you want to separate and you collect that in your in a separate vessel on the side there so in other words we heat this up and let's say one of the components of this boils at say 70 degrees that will then evaporate it up into this tube and then it'll condense against the column here because it's tilted this way the liquid will run down and into this container here leaving the the liquid with a higher boiling point in here which actually brings us on nicely to our next point so if you've got a higher boiling point in there you heat the mixture to the boiling point of the compound you want to separate and basically your higher boiling point compound will remain in this flask here and the one that you don't want within here so you're just doing it in exactly the same way it's just dependent on what you want to collect so distillation is really useful when we want to extract a chemical before it reacts any further so a classic example is alcohols forming aldehydes to carboxylic acids now and when we use an oxidizing agent in there for example dichromate it's a potassium dichromate is used to oxidize alcohols so a primary alcohol will oxidize to an aldehyde but then it will continue oxidizing to a carboxylic acid now if you just want the aldehyde you have to use a distillation kit you have to separate the aldehyde first get it out of that reaction mixture before it reacts any further and produces a carboxylic acid so you need to use distillation to per eight substances where you want to take it out of the reaction mixture before it reacts any further okay so and we're going to look at re distillation and separation so this is basically okay so you've made our product so now we need to purify our product so re distillation is used when we pure purify our volatile substances so we've made it in reflux let's say and we're going to read we're going to read distill it okay so it can purify it further again by using separation but we'll look at that in a moment so what we need to do is separate the useful organic products that we've just made okay in our distillation kit let's say from the impurities and distillation can help us here so it allows us to separate chemicals via boiling point so remember we just seen that before so we can collect the different substances by monitoring the temperature that they boil at and we collect in we're collecting the different liquids as they come out of the condenser so you can see here that we say right let's say if we've got our substance here and we know it's boiling point we can heat it up and collect it in here okay so we can collect it in our flask and depending on what we're what we're after and go so basically we're just read this we just distilling it again to try and get out as much of that impurity which we possibly can and so then what we can also do is we can actually separate it further distillation doesn't give us a very like a guaranteed pure product so we need to take another step to purify it and we use it using separation and so we use and you might have seen this before but separation is where you have a large flask like this with a big bulb on the top of it here and basically a separation funnel can help by if we add a drying agent and into our substance that can help to remove water the drying agent will dissolve and you'll see on there on the next slide the drainage will absolve and the liquid and effectively we can remove water from that but we can filter that through run it through and separate our compounds but let's have a look and see how that works so like I say separation techniques are used to remove impurities that are dissolved in water so let's have a look bring that diagram back again so all the products from distillation I'll put into the separating into the separating funnel so this is this here okay we add water to dissolve the soluble impurities and we create an aqueous solution so you can see you've got an aqueous solution here so we add water to it that's our original compound we're going to add water and not remove any soluble impurities that may be and there will be dissolved in this layer here and then what we can do you can see there so we've got two layers so Gatto impure products at the top and then we've got our a crease layer containing any soluble impurities in there we've got them in there in the bottom layer okay so what we want to do is run that off and you've got to remember to remove the stopper there's the stopper there and we're going to remove the stopper when we're doing this and you might have done this yourself I'm not sure but if you've tried to run a liquid off with the stopper in your factory create a vacuum in the top here and that stops the liquid from running out so you have to remove the stopper to then drain the liquid out very very importance okay so purification so what we're going to do is take the impure product which is this bit this lay here from the separating funnel and we're going to add that to a round bottom flask okay so we've taken all our soluble impurities have now been drained off we may still have insoluble impurities in here so for example may still have water in here so we've got to remove the water from that substance so anhydrous calcium chloride cacl2 that can be added to our impure organic product here and we can give it a shake so we invert the flask can we leave it and what will happen is our an Hydra substance will remove any water or aqueous substances that may be floating around in this and it tries to give us a a pure product so and then we filter obviously once we've done that we filter the the solid drainage and to remove it so we put it through a filtration separate filtration technique - to remove that and in fact that's what we're going to look at now so we've got our solid floating around in our organic substance we need to remove that solid and we separate solids from liquids by using a vacuum filtration so you can see here that a vacuum is used to help separate the liquid and solid components thoroughly so you pour your organic liquid in there with your solid that's in there you ran address calcium chloride and we put on a vacuum normally that would be a some contraption attached to attack normally and that creates a vacuum it pulls your liquid it pulls your liquid through and the bottom here this is the bit that you want and your solid at the top you can affect the read dispose of that will get rid of it so this is the bit that you want to keep here so you can use this type of filtration so very simply we put a bit of filter paper we just wet it a little bit just to create a seal put it on the top of the Buchner funnel which is that bit there and we pour the reaction mixture into that with a vacuum line on and effectively we have a reduced pressure so this pulls the liquid through and the solid to be left in that book the funnel as I've said so again this very simple technique so you might have and you might have seen that you might have seen that as well and you might have used it should I say now if it depends what you want to collect so for example if you want to get the liquid then you've got your liquid in there but let's assume that's typical instead of it now let's assume that actually we want to keep we produced a product and the product as a solid and we've been purifying the solid then a way in which impurifier solid is by is by filtering it like this now you'll have your solid sitting on the top in your book no funnel there so that solid may not be purified so if it is a solid that we're after then we have to recrystallize that solid and to purify it further so let's look at how we can recrystallize so this is if you've got a solid product and you want to purify your solid product so you filter it through here you get rid of some of it but we need to recrystallize so recrystallization is quite a refined technique you've got to be very careful recrystallization so recrystallization is a method to purify solids and the solvents chosen is really really important okay so it works in a very very particular way like I say you've got to refine your technique for this so what we need to do is our just enough hot solvents to the impure solid to dissolve it okay so we've got our solid from our Buchner funnel we've got it in a beaker okay we're gonna add a tiny amount of hot solvent to it and so this means you'll have a really saturated solution so we do not want to add more solvent than we have to just enough to dissolve it okay into our impure product and then what we need to do is we allow as that cools down the solvent cools down we get crystals start to form hence recrystallization and then your impurities will actually remain dissolved in that solution as there's not obviously there's more of your product than there's impurities of there should be and so it takes a lot longer for them to crystallize out so the crystals that you're forming is your product that's what you want and your impurities of Ramin and dissolved in solution and so then once we've got our our crystals then we have to filter to get our purified or solid purified crystals we have to get them and then we wash that with very cold solvent to dry them off so the reason why the solvent is so so important in this case is because you want your impure solids to dissolve fully in hot solvents but it's got to be virtually insoluble when we wash it with the cold solvent so if not then your substance will dissolve in the hot solvent then you can't actually filter it out so the solvent is really important the solvent could just be water it doesn't have to be anything fancy but it has to meet that criteria otherwise you can't recrystallizes okay so now we've purified our solid we need to actually determine you know we need to determine you know that how pure it actually is now that you can did the purity of whatever you've produced depends on if it's a liquid or if it's a solid but if it's a liquid then we're looking at boiling points if the solids were looking at melting points so we're going to look at a liquid so if we've reduced liquid and we want to work out if that liquid is pure then we need to work out its boiling point okay so measuring the boiling point of that liquid can help you to determine if there's any impurities in there and we can basically bring this distillation kit back in now this is if you're testing the purity of a liquid then we do this method okay so we determine the boiling point of the liquid by using the distillation kit that we've seen already and then if we gently heat the sample we can measure the temperature at which it distills using the thermometer okay so we want to measure very carefully when does that substance start to you know start to start to boil when does it start to evaporate and then what we're gonna do is take that boiling point value and compare it against the data Book value of the product obviously we know the product that we're making so we can compare that against the data book now your sample will contain impurities if your boiling point is higher than what's recorded in the data but but also it's about the range in which it boils so in other words if it boils in a really sharp so they can they've got a very specific boiling point then you know got a pure product if it's kind of boiling over a range of different temperatures then you know you've got some impurities in there it's not a pure product what we've got to be really careful though okay is that various organic compounds actually have the same boiling point so it's not a it's not an exact science for this one what you've ain't got to do is take that purified sample and run it through say like NMR machines infrared machines mass spectrometers you know all these different types of analytical techniques which you'll see towards the end of year two so it's the last topic where you look at different methods of analytical techniques to Archy you know nail down exactly what you've produced okay so let's say you've produced a solid now and you want to work out if your solid is pure well what we're doing is we're going to measure melting point instead because obviously we got a solid and we're going to see while it's melting point is now we use a special bit of kit something like this and this is used it's a melting point apparatus and basically it's used to measure the melting point of your solid substance so we're going to do this in a really simple way where we take our sample or solid sample and we put it in a capillary tube so you might have seen a couple of YouTube it's just a very thin glass tube that you have to seal the end of you put it in a bunch of room and it melts the end of the tube and then what you do is you tap your your capillary tube against a solid product like that okay so you tap it and then what happens is your solid or then get pushed into that tube and then what we do is you then place it into this machine here okay so you put your sample you capillary tube in there and then you look down this bit here so you've got a viewfinder that you look down and basically what happens what the machine will do is it will gradually increase the temperature really slowly until the substance starts to melt and what you're looking for here is a temperature range okay from when the solid just starts to melt you'll see it just start to turn into a liquid and then when it fully melts so what you want to do is record down what that range is and so then essentially the sharper that range then the less impurities you got if the range is quite broad then you got impurities similar to what we did with the liquid but again we compare the value that we got against data book values and we're looking for the same type of things we've seen before and if it contains impurities and we'll get a broad melting point but also if your substance does contain impurities the melting point will be lower then then what it says in the data book that suggests that you do have some impurities in there so you can see all of this is vitally important for organic chemistry because obviously if we made a product we need to know a what we've produced and be is it pure if it's got all sorts and that's no good particularly in pharmaceuticals you know you really can't afford to have impurities in that drug you know you need to make sure you've got a pure and a pure product in there okay and that's it so that's the end of this video on carboxylic acids and derivatives as you can see there's a lot of information there a lot of mechanisms a lot of reactions and there is a full range like say of a QA and revision videos like this on Alawis chemistry YouTube channel as long as as as well as whiteboard tutorials as well looking at general information about chemistry and also some exam technique videos as well and they're all free all I ask is you hit the subscribe button that would be absolutely fantastic and also again these are available to purchase really good value for money just click on the link in the description box okay that's it okay bye bye