[Music] hello my name is chris harris and i'm from alley chemistry and welcome to this video on carboxylic acids and derivatives and nitrogen compounds basically it's topic 18 and 19 and kind of mashed together obviously this is for the cie um specification so it's the cambridge internationals so if you're studying the cambridge internationals um syllabus then this video is perfect for you and obviously as the name suggests we're going to be looking at some carboxylic acids we're going to be looking at derivatives of them so for example esters and look at some nitrogen mechanism or compounds that contain nitrogen in there as well um so this is obviously just one part of the video there are a full range of all the topics for cie on ally chemistry youtube channel and please go and have a look all i ask is you hit the subscribe button just to show your support and that'll be absolutely brilliant um also these are a series of powerpoint slides and they're actually available to purchase if you want an electronic copy yourself and they're great value for money if you click on the tesla link in the description box below that's the link where you can buy them from then um you'll be able to have a look at them there i've kind of bundled all the organic year one stuff together but i have bundled them further into full year one and year two um um kind of packages as well so have a look in there the great value for money anyway okay so let's have a look and see what we've got here so we're going to start with um obviously carboxylic acids now you'll probably find in you probably if you've watched the other videos you'll hear this all the time but it's just important just in case this is the first video you watch um all the cie topics kind of inter they kind of overlap each other there's a lot of um kind of blending of some of the concepts into the individual topics and particularly the nitrogen um the nitrogen compounds one there's a lot of kind of the stuff they've seen before so it just kind of repeats it or reinforces it i suppose is what see i say so um yeah so if um yeah i'll try and bridge them as much as you can but if you haven't seen the previous videos so 1 to 17 yet it's a good idea to get a good idea of get a good kind of grounding of them first before you watch this video um but i will try and bridge as much of it as i can just so you know where i'm referring to okay so a carboxylic acid they have the carboxyl uh functional group here which is c o o h functional group looks like coo um functional group with it contains the carbonyl group that's the c double bond null group which we've seen before and the hydroxyl group which is o h so it contains both groups and obviously them topics were previous topics so it's effectively like it's the mashing together of both of them so carboxylic acids are named by finding the longest carbon chain and then adding oil acid at the end now the nomenclature of these obviously we looked at the introduction to as organic chemistry topic which i think is topic 13 and that obviously goes into the nomenclature a little bit more detail obviously this is just looking at carboxylic acids in particular but effectively in the relatively straightforward actually when we're naming carboxylic acids um the carbon on the carboxyl group is always carbon one and the carboxyl group will always be at the end of a molecule because it's a carboxylic acid so this one has got two carbons so it's ethanoic acid and this one is four chloro three hydroxy butanoic acid you can see i've just tried to add some extra groups in there to kind of show you and the last one is benzoic acid now if you're doing the full a level you'll see benzene a little bit later on in the um in the in the syllabus obviously we don't look at it in a great deal but we don't look at it at all really um in in year one so but this is just an example of a of a benzene ring so you've got this to look forward to in in year two okay so how do you make carboxylic acids so carboxylic acids can be made um from nitriles aldehydes and primary alcohols so you've got various meth different methods of doing that so let's look at primary alcohols and aldehydes first and as you might have seen in the um carbonyl um carbonyl chemistry topic um then you would have seen some of this already so primary alcohols and aldehydes they're oxidized to form carboxylic acids and we use an oxidizing agent to do that so normally it might be something like um dichromates for example potassium dichromate to do this so there's your primary alcohol here primary alcohol oxidized to an aldehyde and then that oxidizes again to a carboxylic acid so using say dichromate and but they can also be made by the hydrolysis of nitriles as well which you will have seen previously as well but not this reaction so there's your nitrile there so nitriles have this cn group c triple bond n group at the end there reacts in it with water and some hydrochloric acid an oxidizing agent you form your carboxylic acid and you form ammonium um ammonium chloride as well obviously with the nitrogen being kind of pulled off so these reactions here are obviously um the methods in which you can make carboxylic acid so fairly straightforward okay and carboxylic acids they're kind of properties and they are weak acids and they react with carbonates like other acids do to form carbon dioxide um and they react with bases to form salts so let's have a look at some examples now carboxylic acids they are weak acids now what that means is they dissociate partly so they form some h plus ions and a carboxylate ion but if you look at the when we looked at equilibrium in the um in a previous topic then you'll notice that um obviously strong acids dissociate fully and you produce loads of h plus ions carboxylic acids are example of a weak acid and equilibrium kind of lies um towards the left rather than um actually producing those of h plus signs so there's your equilibrium reaction there so obviously equilibrium lies well to the left you don't get many of these and this is why carboxylic acids are actually cast as a weak acid and and obviously the whole family of carboxylic acids are so um as they're um as their acids and they react with carbonates as i mentioned before and they form a salt carbon dioxide and water so let's have a look so this is just your classic acid um acid base reaction but anything where you're reacting it with a carbonate you will form carbon dioxide so you can see here you've got your carboxylic acid so this is ethanoic acid reaction with sodium carbonate will form um sodium methanoids which is this substance here plus water and carbon dioxide and obviously the reaction between ethanoic acid and sodium hydroxide so this is an um sorry sodium hydrogen carbonate should i say not sodium hydroxide um then obviously this will form um sodium methanoids carbon dioxide and water in the same it's just different form of carbonate that's all and obviously um acid base reactions and they are very no excuse me um let's hear fever kicking it um so yeah so these the reaction between an acid and a base you've got your acid carboxylic acid there reacting with the base and that will form your salt plus water which is at the end there so your salt will be sodium ethanoate and this is just the classic acid base reaction as you would find anywhere else okay so as they are acids they also react with some metals as well so well for example we're going to look at magnesium here um and they will also react with ammonia to form ammonium salts too so let's have a look so here's the reaction between ethanoic acid and magnesium so you've got ethanoic acid which is here reacting with magnesium and you form your um salt um so you form your salt yes this is your salt here and you form hydrogen gas so like with a lot of metals react with acids they will always produce hydrogen gas and obviously the salt here as well and the reaction between ethanoic acid and ammonia is here so you've got ethanoic acid plus ammonia and that will form your ammonium salt as well that's produced so you'll always get this remember when you react ammonia with um with an acid you always just form salt you won't actually produce any water with it okay so let's look at some derivatives of carboxylic acid so a derivative is like a side branch i suppose so um we can react alcohols with carboxylic acids and we can also react with acid anhydrides as well but you won't really see a lot of them it's just an additional chemical it's mainly the carboxylic acids that we're going to look at here of course um and this can be used to make esters and they have the c or or group and there's methyl or some of those um carbonyl groups that kind of flank the two ends of this functional group here so an ester is produced when basically we react a carboxylic acid with an alcohol that's it and we use a sulfuric acid catalyst and you might have done this in the lab as well in because um you know it's quite a straightforward reaction to be honest so here's an example here's your carboxylic acid reacting with your alcohol um with an acid catalyst that'll form your ester which looks like this and water and just to try and illustrate where the kind of components come from so the blue is obviously the carboxylic acid this is your alcohol now what happens is the o r bit from the alcohol basically swaps places with the o h bit on the carboxylic acid so that's basically the difference and then how they're joined together and then obviously you form water as well so i find when you're looking at these types of reactions that actually it makes it easier when you actually call the atoms and you can see what's going on all right okay so carboxylic acids um they can be reduced to alcohols and they can also be reacted to form acyl chlorides as well so with acyl chlorides acyl chlorides again you'll see that more in year two chemistry rather than a s but it's just kind of introducing it so carboxylic acids and they can be reduced um however they need um a powerful reducing agent and the reducing agent we normally use is something called lithium aluminium hydride so lilh4 um in a dry ether solvent so that's the solvent that we use so there's our carboxylic acid we represent a reducing agent with four and and a hit so with the h in the square brackets and you're gonna need four of them um with some water and then you produce your alcohol as well now the reason why you need um you need four of these is if you look at the number of hydrogens on this side we've only got four of them on that side on this side here um we've got three four five six we've got six hydrogens on on this side here so you're gonna need a reasonable amount of hydrogens to actually um make that work okay so um this is what you produce so there's your there's your ethanol there your alcohol okay and some of them obviously form to produce your water okay ester hydrolysis so esters can be hydrolyzed okay so this means um split using water so hydrolysis hydro meaning water lysis meaning to break or to split um however it can be sped up using an acid so we call that acid hydrolysis instead or base hydrolysis so this is where we effectively break an ester apart to form its components so let's look at acid hydrolysis first so here we're going to use a dilute acid to split an ester into a carboxylic acid and an alcohol so and we can use sulfuric acid or hydrochloric acid and obviously the reaction is conducted under reflux for this so let's have a look we've got our ester here and again try to color coordinate so you can see kind of the different components from it obviously this is originally from the carboxylic acid that bit is originally from the alcohol and we're going to use an acid hydrolysis there's h plus ions now what we form is your um carboxylic acid which is here obviously the the water so with the water here that'll join from the oh and then obviously you form your alcohol here on the right hand side so you can see here you've got ethanol so the addition of more water which is this bit here will shift equilibrium to the right and we get more product that's formed so generally you would add a reasonable amount of water into this and this should help push equilibrium to the right and obviously you form the components that made up the ester in the first place which is your carboxylic acid and your alcohol there on the right okay let's look at base hydrolysis so here we're going to use a dilute base instead to split the ester and we're going to split that into a carboxylate ion and an alcohol and obviously here we're using sodium hydroxide we conduct the reaction under reflux so that's obviously heating it up with your liver condenser um vertically upwards so there's your ester and there is your height your hydroxide ion that's your base as you can see there and obviously that will form your um carboxylate iron here and then obviously form your alcohol which is there as well so you can see all of this is is balanced and obviously we're splitting this um this ester into its components that's hydrolysis okay so this is base hydrolysis okay so esters are actually really useful um they're used commercially in industrial processes so perfumes and food flavorings so some esters have a sweet smell such as pear drops for example this makes them ideal in fragrances you might have seen these before like you say you might have made them and they're used in solvents as well so things like adhesives and glues etc and and they have a low boiling point and they evaporate easily and this obviously makes them really valuable in making glue so obviously when you pour the glue or you put glue on a let's say on a paper then you expose it to the air and that allows it to evaporate um and obviously that then leaves behind this hard resin which obviously cements two components together and they're also used in plaster sizes as well so they used to make plastics a little bit more flexible and you'll see um later on in topic 20 when you look at um polymerization but uh they they they're basically used of the can be used to allow a reaction to a curve for for polymers um the problem is they can leach out the plastic over time so the um the plastic can become brittle over that period of time as well so um it's obviously not uh um well some plastics are more durable than others but um some some of these plasticizers can leach out you can weaken the plastic okay so we're going to look at some uh aliphatic amines and we're going to look at seeing how you can make some of these so aliphatic amines are made by reacting a halogenoalkin with excess ammonia now a lot of these reactions you will have seen in previous topics this kind of falls into the nitrile uh sorry this falls into the nitrogen compounds topic so this is topic 19 but a lot of these i'm not sure why cia have done this but a lot of these are just recalling from previous topics so it's nice to kind of summarize them of course but don't be kind of sitting there thinking okay i've seen these before why is he doing this for um it's obviously all in the specification so it is going to be quite important so no harm going through it again anyway so um antiphotic amines are made by reacting a halogenoalkane with excess ammonia so we can take a halogenoalkane reacted with excess ammonia and we need to know the mechanism for these as well now here we're going to use a nucleophile and this this case we're going to use ammonia so remember a nucleophile has a lone pair of electrons attached to it on the nitrogen this is going to go in and attack the delta positive carbon um and then it's going to kick off this chlorine there okay so that's your nucleophile and then obviously that kicks off the chlorine there so we form an intermediate as you can see here um and this is an alkalinium salt that's been produced it has a positive charge on the nitrogen and we're left with a cl minus that's unceremoniously being kind of booted out of the original molecule and now it's kind of floating around now the problem is this is not very stable because this obviously got a positive charge here uh that's got a negative charge but it's floating around on its own so this is where you need an extra ammonia molecule this is why we use excess ammonia because you'll need two molecules ammonia per molecule of um halogenoalkane so what i've done as i've taken the nh3 and i've split it up into the displayed formula so you can see where the n plus is in hydrogen now this time this is actually going to act as a base this time okay so the lone pair of electrons is going to go and go for this proton and take this proton so it's going to be a proton acceptor so it's a base and then the electrons from this bond are then going to go in and neutralize that positive charge there and that'll leave us with our nh2 group there so let's have a look there we are and then we form our primary amine and then what we have is our ammonium ion because this will obviously form an ammonium ion nh4 plus will react with a cl minus that was kind of made homeless over here and now they're joined together to form ammonium chloride so you produce these two products but the main product is this so you form your primary amine and obviously that's made by using reaction with ammonia okay so like i said before two molecules of ammonia are required and this is why the excess bit is so important okay so let's have a look at um reaction so halogenoalkanes with the reaction of cyanide ions again to make nitriles so these are nitrogen compounds of course so here we're going to use warm ethanolic potassium cyanide and that will obviously give us the source of cyanides and we're going to carry this out under reflux so very similar reaction here's your halogenoalkane it's got this permanent dipole here delta positive delta negative lone pair of electrons on the c on the um the cn minus ion to the cyanide this is going to act as a nucleophile it's going to attack the delta positive carbon and then it's going to kick off this chlorine here there we are okay so obviously this bond breaks there we are um and obviously you form this so you form your nitrile that's formed and obviously you extend the carbon length now here and then obviously form your cl minus which is over here as well your chloride ions so the overall reaction here is obviously your halogenoalkane reacting with potassium cyanide and that will form your nitrile plus your potassium halide so obviously this bit here this cl minus will react with the spectator ion of potassium which is which will be knocking around as well okay so potassium cyanide reacts with carbonyl compounds to form hydroxy nitriles as well so they were just nitriles that we'd seen before but we can form hydroxyl nitriles so the reaction occurs via nucleophilic addition this time um and um it's obviously we use the nucleophile which is the cyanide ion so it's exactly the same it attacks the carbonyl group which is your c double bond o and it adds on to make your hydroxy nitrile and hydroxy nitrile as you probably guessed contains a hydroxyl group which is your oh group and your nitrile group which is the cn so cyanide is used so potassium cyanide should say is used to produce the cn minus signs in the first place and what we do is we take potassium cyanide dissolve it in an acidic solution and then what that will do is it will provide us with our cn minus signs in the first place these cn minus ions then act as a nucleophile so remember they go for the delta positive carbon make sure you show your polarities in the exam as well that's going to be really important but this goes in attacks the delta positive carbon this breaks and forms your sorry this breaks the double bond and forms a negative charge on the oxygen and obviously we've got this intermediate here okay um hcn can be used um as well you don't need acid with hcn it's just more difficult to use practically so normally you'd use um kcn to do that it's just easier to handle okay so let's finish off this mechanism oops there we are okay so then what you've got is this o minus this intermediate will react with the h plus ions that are in solution anyway because it's acidic when we dissolve this in acidic solution and it's the acid that will provide a source of h plus ions so lone pair of electrons on here this is not very stable at all so it's going to go straight for this h plus electrons move from here on to the h plus sign remember the arrows show the direction of electron transfer so it's going from this lone pair here to the h plus and then this will form your hydroxy nitrile which is this product here okay so the overall reaction as you can see here this is the aldehyde and this is for a ketone so this reaction will occur for an aldehyde or a ketone it doesn't really matter the the mechanism is the same so the only difference is if we use an unsymmetrical ketone or an aldehyde apart from methanol then what we do is we get a mixture of enantiomers um that that's produced in this in this reaction you would have seen enantiomers in a previous topic as well um now enantiomers means that you'll have optical isomerism and again you would have seen that in in previous topics about what optical isomerism is so um i believe that would be in um because this is to do with um let me just check my notes so you've got hydroxy compounds um i believe this optical isomerism is in hydroxy compounds um in that topic which is topic 16 but it's also in topic 13 as well which is the introduction to as organic chemistry when we look at different types of isomerism and we talk about optical isomerism there so just make sure you look back at them topics if you're ever unsure on anything like that okay so that's it that's everything you need to know for carboxylic acids derivatives and nitrogen compounds um quite a few reactions there to be honest a lot of them are just overlapping from uh or some of them anywhere overlapping from previous topics there shouldn't be anything too new there not too much anyway like say there's a full range of ci videos um on the alloy chemistry youtube channel uh please hit the subscribe button to show um your support for this project that'll be really really good like say all these slides are available to purchase if you wish to do that and if you click on the link in the description box for the test shop that will take them there great value for money and great to supplement your existing revision materials but um that's it hope that's helpful bye bye