Aldehydes and Ketones part 9

Added: 2026-05-11

[00:00:00]coming to the aromatic aldehydes and ketones so let me draw the structure of aromatic what you can say ideas and ketones so this is a structure you see it look at the board this is carbon this is your alkyl group and this is double pondo fine now definitely oxygen will pull the electrons towards itself you know that oxygen is more electronegative it is going to pull the electrons towards itself now listen here this particular one benzene ring all right it is showing plus r effect plus r due to which this pair of electron goes to this particular carbonyl carbon due to plus r effect arming sort resonance this particular pair of electron goes to this carbonyl carbon hence what we find here that is the electro positive character of the carbonyl carbon decreases due to plus our effect the electro positive character of the carbonyl carbon decreases all right so you have ready all these things resonance and all the things you have studied just once more i am doing and showing to you so here it is c it is r and its single bond o on it and it is becoming double bond here so this is positive and this particular one is negative and here due to deficiency it becomes positive all right again it goes on the structure will go on okay you know that how the structure goes on the resonance it goes on how it is so that is this particular one from here this will come here okay this will be coming here this year of course in this position i can say that if you don't understand i can say to this position it comes clear and hence the positive charge will come here okay the positive charge is going to come here in this way it goes on the resonance i'm not going to show you the resonance effect already just i told you this particular one it in this way will go on then this will come here and it goes on there is none so what you find is that due to plus r effect due to plus r effect listen carefully the positive electrophosphate character of the carbonyl carbon is what you can say decreasing see it is donating electrons to this particular bond and the electroplastic character of the carbonyl carbon decreases now you can see me here he said that is minus i effect also because benzene ring is minus side effect done correct benzene ring undergoes minus eye effect aryl group minus eye effect electron withdrawing but here listen carefully the plus r effect predominates over minus i effect plus our effect is more stronger here than minus if x it predominates over minus i effect due to which ultimately what happens is that the strength of the carbonyl carbon electroplastic character of the carbonyl carbon you can say that or strength of the carbonyl carbon we can say decreases not it of course benzene ring undergoes minus effect it's an electron withdrawing group it's not an electron donor group it's an electron group agreed that is going to withdraw electrons but here when plus r effect is there and minus i effect is there then plus our effect will predominates over minus hive because it is stronger than minus sigma due to which as plus r is stronger due to which what you find is that the strength of the carbonyl carbon or the electro positive current of the carbonyl carbon decreases so aromatic aldehydes and ketones are less reactive in nature because of that compared to aliphatic aldehydes and ketones aromatic aldehydes and ketones are also less reactive in nature due to plus r effect fine now next is among our aromatic aldehydes and ketones we are having this particular compound isn't it we can have this compound like ah c double bond which this is nothing but benzaldehyde if we cancel that clear we can have there is alkyl aryl ketones we can have it of course here alkyl aryl ketones like coch3 we are having this is known as alkyl aryl ketones we can have also two aryl group also we can have it that is diaryl ketones we can say i do not have the space i am drawing a small one i hope you understand this we are having two arrival groups so die allyl ketones we are having here alkylaride ketones we are having alkyl ketones got it uh sorry we are having here id heads ketones we are having aldehydes here we are having alkyl aryl ketones and we are having diarrhea alkytons so which is more reactive here definitely this is more reactive here why because h atom is there here ch3 group is there ch3 group is electron donor group same thing cs3 group is electron donor group electron donor group what it will do it will decrease the uh carbon electrophosphate character of the carbonyl carbon due to which the reactivity decreases now what about here here what we find is that the plus r effect predominates over minus i effect plus our effect predominates about the minus sigma this is a bulky group also it's a bulky group also this particular one this two group arrived bulky group due to which the reactivity decreases so hence i can say benzaldehyde this is your acetophenone and this is your benzophenone so benzaldehyde is more reactive than what you can say acetophenol which is further more reactive than benzophenone in this way reactivity decreases all right in case of aromatic aldehydes and ketones also we can say that fine now next so all this in general we have seen it the mechanisms and all these things we have learned it now we will see some reactions we will see some reactions of the aldehydes and ketones we will see it now look here that is we are having ch3cho see all this i am writing in this way by doing so what it happens you know i remember it is sp2 hybridized it is trigonal planar and all those things i remember it so always try to write the reaction in this way and it's easy also okay now nah so3 what will happen here that is you know that this is positive and this is negative on it here nh so3 what you find n a is positive and hso3 is negative isn't it so in this way the reaction is going to take place so what will happen here ch3 that is ch here o is going to react with that is nothing but what is that any and here it is carbon is going to react with hso3 fine that is ona and hso3 it is going to be but here you see listen carefully here that is this particular group even here we are having that is two options here either oxygen can react with sodium or oxygen can react with hydrogen now tell me oxygen will go with this which particular group with sodium and hydrogen because here sodium is also electro positive hydrogen is also electro positive done all right but first the reaction is going to take place in this only because o is going to react with an a and c is going to react with h okay positive negative this positive negative done but after the reaction has taken place now often is having two what you can say attacks from sodium also that actually then hydrogen also there so which attack will be more stable think of which is more stable hydrogen because it's a smaller group the bond will be smaller bond is smaller means smaller is the bond stronger is the bond all right and oxygen is more readily attacked by hydrogenated so hence after that the rearrangement is going to take place and due to that what will happen ch here it will be oh and here it is so3 na and you have seen it also just knife it showed you the mechanism where you are having the oxygen that is hydrogen goes with oxygen hydrogen goes with oxygen okay hydrogen goes with oxidizing it in the mechanism so in this way it will be attached no doubt in this way it will be attacked by the sodium and hso3 but what you find is that when they come closer then it is hydrogen also attacks this oxygen sodium side axis oxygen so which will be uh more stable definitely hydrogen why because hydrogen is a smaller group smaller atom bond is smaller bond is stronger more stable we can say that so hence i ultimately will say that this product is also found and this product is also found but this is a minor product and this is a major product you'll be getting it so to say practically this is around 5 to 10 percent and this is around 90 to 95 percent will be getting it so which will consider definitely this one so this way so this reaction takes place now what is the name of this compound is this acetaldehyde sodium bisulfate we can say that all right acetaldehyde sodium bisulfite we got it this particular compound so by sulphite not bisulfite bisulfite as radiated sodium bisulfite now next is this reaction also can take place with acetone here ch3 group will be there so if ch3 could be there acetone this is acetone now what will happen just have to put your ch3 that's it finished same thing it is acetone sodium bisulfite we got it in this way so this is the first reaction you understood done now next is now next is after that when it reacts with hydrogen cnid hcn we can say that when it reacts with hcn now see it ch3 cho plus hcn what will happen okay we already studied ch3ch it is oh and it is cn all right we got it so what is the name of this compound acetaldehyde cyano hydrine acetyl dioxide hydrogen if you take acetone here ch3 group then what will happen here also ch3 then you will get what acetone acid cyanohydrin can hydrate or we can say acetone cyanohydrin will be getting it fine now see cyanohydrin group is highly a reactive group this particular group is a highly reactive it forms several compounds it forms several compounds when it undergoes hydrolysis when it undergoes reduction it undergoes it forms several compounds we can say that it is a highly reactive group all right fine so let us see what it happens see ch3 ch here it is uh what is that oh and here it is cn so first it undergoes hydrolysis h2o slash h plus first it undergoes cytorosis so when it undergoes hydrolysis what is going to happen here is that you will be getting there is nothing but ch3 here it will be h here it will be oh and here the cn will be converted into co h all right it is being converted into co it's now you might be thinking where there's some nitrogen goes where the nitrogen goes the nitrogen is being converted into what you can say ammonia and what is this compound known as lactic acid this is called as it is known as lactic acid you have studied in optical isomerism if you remember it it is lactic acid now this particular ah here if you heat it this reaction if you are going to heat it further then what is going to happen understood what is happening here this is taking place in acidic medium this one and it forms lactic acid and where this nitrogen goes cn all right now remember it since here the reaction takes place in two steps i have done it in one step listen carefully all of you reaction takes place in two steps in the first step cn reacts with water and h plus ion to form co and h2 amides all right that is called as incomplete hydrolysis in the second step co and h2 further reacts with water and h plus iron to form cooh which is known as complete hydrolysis so here complete hydrolysis has taken place again i repeat you might be thinking how we got co h where that's nitrogen goes and where it goes i don't understand okay i'm explaining you cn in the first step first h2 and h plus cl h2 h plus but it forms here it is you will be getting co and h2 amines you'll be getting amides all right that is called as incomplete hydrolysis incomplete that is known as now in the second step got it two h2 and h plus ion what is going to form amines will be further hydrolyzed to form acid all right and where that nitrogen will go what i said you nitrogen will form ammonia and ammonia will react with h plus ion h plus later let it be sulfuric acid let us say because generally x plus ion in sulfuric acid to form ammonium sulphate that's a secondary product i'm not concerned with that understood no fine now next is what i said if you further heated this one if you heat it this one this particular one the heating is being done so when heating is being done what will happen you know ch2x so this h and o h will be removed when you heat it further this hoh will be removed and hence what is the product we'll be getting it here it will be ch2 definitely how hot will be removed this ah carries negative charge and this will give you double bond uh because this will become positive h plus and this carries negative charge from h minus x plus h minus forms water so hence we get a double bond here so ch2 double bond ch minus water okay so in this way you will be getting this particular one so what is this compound is it is known as allylic acid it is called as allylic or we can also say acrylic acid also we can call it as audit that is acrylic acid or we can say allied cancer you would be getting in this particular manner fine so this is the reaction you got it with c n o hydrine one reaction i said now next another reactions when it reacts with ammonia what is going to happen see ch3 here is ch it is oh and cn when it reacts with ammonia ammonia will generally write it this way h and h2 so what you will be getting here cs3 ch here it will be nh2 and here it will be cn all right now you might be thinking where that uh o h group has gone this o h reacts with h to form water it is being removed now what we will do is that we will go for complete hydrolysis will go for complete hydrolysis complete hydrolysis means two h2o slash h plus just now i say what will happen it will ch3 this is ch this is nh2 and c n will be converted into c o h what is this known as alanine what is alanine it is an amino acids it is called as alanine a l a n i n e the name of this compound is i don't have a space here a-l-a-n-i-n-e got it which is nothing but it's an amino acid so we are synthesizing amino acids from aldehydes and ketones we can say that we are synthesizing all right clear and this particular reaction is called as striker synthesis s t r e c k e r apostrophes strickes synthesis we can say that clear the production of amino acids or we can say sprinkle synthesis now next after that acetaldehy as uh that is acidic we can say what is going to happen so here one more reaction is left ch3 then ch it is oh and the cn we can say that got it it undergoes reduction h2 slash ni we can say and heat it or you can also take li lh4 a reducing agent which will give you an ascent hydraulic either you can take h2 slash ni and heated because this is a stronger reducing agent mind it compared to lil h4 h2 slash ni is a stronger reducing agent stronger so i have taken that you can also take a lh4 so here you'll be taking four nissan hydrogen in that case so what will happen here that is ch3 it will be ch here it will be oh and here it will be ch2 and h2 see two four hydrogen here and then here two hydrogen is being added so in this way we got stage three ch so it is nothing but you name it this one so here will be nothing but we'll be starting from here 1 2 3 we can say that one two three three carbon atoms is there so when three carbon atom is there then we will start from here this particular group we can say that clear because if you start from here also to second carbon here also if you start it is second carbon so it is nothing but one amino propane to all see first question amino one am i know propane to all we can say that clear in this way we can make the particular compound we can say that fine so this we got it with the acetaldehyde cyanohydrin the reactions which you got it right now next we will see the reaction with grignard region already we have seen it in alcohol chapter you have studied when formaldehyde reacts to the grunt region it gives you what it is nothing but it will give you ethanol alcohol not it formula yet when estradiol reacts with the grignard region it will give you what secondary alcohol propane to all you go and see in alcohol chapter we've done it ch3cho and react with ch3 mgbr we'll give you what is that propane to all and when ketone that is acetone ch3cocs3 when reacts with ch3 mgbr it will give you nothing but tertiary butyl alcohol so we got it one degree alcohol two degree alcohol and three degree alcohol in the preparation of one degree two degree and three degree this reaction we have done it so again i repeat when formaldehyde reacts with ch3mgbr but it gives you ethanol one degree when acetaldehyde reacts with cs3 mgbr it gives you two degree alcohol that is propane to all when acetone reacts with ch3 in gbr it gives you three degree alcohol that is known as tertiary alcohol or tertiary butyl alcohol we can say that clear so we have done it this particular now next is we will see when ah aldehyde ch3 cho reacts with c2h5h all right when reacts with c2h5 h what what is happening what will happen here on it so here you see we'll take dry hcl gas dry hcl gas i did it now what is the function of dry heal gas it will absorb moisture water it is going to absorb moisture for that reason i have taken dry exhale so this also acts as a dehydrating agent it removes water all right so hence what i am going to get it see i am going to get the product ch3 ch here it is oh and oc2 now you might be thinking where the water is removed in the first case it is not removed it undergoes addition reaction it undergoes adhesion reactions you can say that o it goes with x and goes to h5 now you see the second step second step again c2h5 c2h5oh and dry hcl gas again you see what is going to happen there is ch3 here it is ch here it is oc2h5 and here also oc2h5 now you can see water is removed now you can see water is removed here o h and this h see here o h and this h o h what is that water is removed here so minus water clear and oc2 h5 is being added in place of oh because this oc pressure is already here just you have to see this edge and this which is removed so what is the meaning also dhy is being added here so hence what is the name of this compound this is called as hemiacetal hemi half all right hemi acetal got it and this is called as acetal we can say that hemi acetal and this is known as acetal sodosa hemiacetal or acetone i should say that now this again it will react with water this will again react with water this particular one in presence of acidic medium to give you acetaldehyde ethyl alcohol very simple because this is a reversible reaction sorry i forgot to write it here this is reversible this is reversible reaction this is a reversible reaction you can see so hence this particular compound when it reacts with water and h plus iron it is again going to form i still did an ether alcohol you'll be getting it in same way you'll be getting it clear but one thing remember it this reaction is not been given by ketones ketones has got no reaction with monohydrate alcoholics this is monohydrate monohydrate alcohol it has got no reactions monohydrate alcohols ketones has got no reactions okay thank you very much and the next day we will see