CHEM 213 Exam 3 Part 2

CHEM 213 Exam 3 Part 2

chem 213 organic chemistry exam three material part 2 we’re going to go ahead and go through all of chapter 19 in textbook aldehydes and ketones and also nucleophilic addition reactions aldehydes and ketones are characterized by the carbonyl functional group we have with an aldehyde on the carbonyl carbon there’s going to be a hydrogen for an aldehyde where we don’t have that for ketone so the R groups in a ketone can never be a hydrogen otherwise it reverts back to an aldehyde now the smallest aldehyde this our group can be a hydrogen and that would be the smallest of the aldehydes but keep in mind on a ketone these are groups cannot be hydrogen these compounds occur widely in nature as intermediates metabolism and biosynthesis now aldehydes and ketones in every organic textbook they’re always separated from the other carbonyl groups and that’s because aldehydes and ketones are bonded to substituents that cannot stabilize a negative charge and therefore cannot act as leaving groups what is meant by that is on the left side or right side of this carbonyl group in the ketone that I’m showing you here you only have carbons to the left or to the right just carbons you don’t have something more electronegative as you do for example and esters or a minds where you have a nitrogen or you have an oxygen so keep that in mind that’s why these are separate you have just hydrocarbons on the left or right and those cannot stabilize a negative charge and aldehydes and ketones behave very similar so we’ll be taking a look at those together let’s talk about the different pieces of aldehydes and ketones you have a carbonyl oxygen carbonyl carbon alkyl groups and acyl hydrogen and we’ve talked about this acyl hydrogen before when we talked about proton NMR if you guys remember that from our proton or spectroscopy section so the carbonyl carbon is sp2 hybridized and forms three sigma bonds it has a 120 degree bond angle the carbon oxygen double bonds are polarized because of the high electronegativity of oxygen relative to carbon the carbonyl carbon this guy right here is positively polarized it’s electrophilic a lewis acid and reacts with nucleophiles conversely the carbonyl oxygen this guy up here is negatively polarized and nucleophilic known as a Lewis base physical properties of aldehydes the melting point of aldehydes varies non systematically with increasing molecular weight so this is actually something unusual typically if something weighs more for compound weighs more its melting point is higher well in it and it increases systematically well this is unusual the melting point of an aldehyde varies non systematically so this means I can’t predict only on molecular weight if one aldehyde will have a higher melting point than another aldehyde I can’t predict that it’s non-systemic aldehydes have higher boiling points the boiling points of alkanes of similar molecular weight due to the dipole-dipole interaction so on the previous slide we commented that the carbonyl carbon is slightly positively charged and the oxygen is slightly negatively charged so what happens when these guys get together in the liquid state because we’re talking about boiling points here when they’re liquid state the polar oxygen here will have a polar dipole-dipole interaction with a carbonyl group on another molecule and that to another one and what this does is it causes them to have an intermolecular force a dipole-dipole interaction that makes their boiling points higher that means in order to get this molecule for example off on its own as a gas it has to overcome this interaction also so it takes more energy the bullying points of aldehydes are lower than the corresponding alcohol do the lack of hydrogen bonding so what this tells us is we do have two intermolecular forces now mentioned up here we have the dipole-dipole interaction that happens with aldehydes but what but we’re also looking at the hydrogen bonding of alcohols so what they’ve done is the rank them for us we now know that hydrogen bonding is a much stronger intermolecular force than dipole-dipole interaction that’s what this is telling us also now we do have a systematic increase of boiling points with molecular weight I want you to contrast this with letter A so letter A says non systematically melting points of aldehydes varies non systematically with increasing molecular weight but it

increases systematically for boiling point that’s normal that’s what we’re used to seeing so so far the only unusual piece is letter A here we would be able to predict the boiling point if it has a higher molar mass it would have a higher boiling point we are able to predict that physical properties of keep ketones the melting point of ketones is systemic with increasing molecular weight so that is what we expect the more ways the higher the melting point is that’s something i can predict with ketones ketones have higher boiling points than boiling points of alkanes of similar molecular weight and that has to do with that dipole-dipole interaction we saw on the alkane section it’s the same thing for ketones and the boiling points are lower than the corresponding alcohol do the lack of hydrogen bonding that’s exactly what we saw also in the aldehydes and again for the same reason it’s the intermolecular force of dipole-dipole interaction that causes it to be a little higher than alkanes but remember the interim unlike the force of hydrogen bonding is stronger than the dipole-dipole that’s the same as the aldehydes and there is a systematic increase of boiling point with molecular weight so going back and taking a look at this melting point thing between aldehydes and ketones and boiling point the they all behave as expected with the exception of the melting point of aldehydes so we have an increase with molecular weight increases the boiling points of both of them an increase of molecular weight increases the melting point of ketones systematically but it does not do that with ketones here we have again from that website that I like compound interest and I have the link over here again for you is the aroma of fresh baked bread and I noticed on this poster that they made that there’s both aldehydes and ketones represented here so you might want to take a look at this I thought this was pretty interesting so as I was looking up ketones I’ve heard of ketones before when they’ve talked about biochem and what happens in your body so I wanted to look up a little bit about ketones and I found some I I found some information of ketones with talking about diabetes and and bad breath so I thought this was an interesting thing to bring in here so what are ketones biochemical interest they’re basically when your body begins burning fat instead of carbohydrates for energy it also is tied to the amount of insulin in your body so I thought I’d put this in here so if you want to take a look at this I put the link to the main article on here about type 1 diabetes and type 2 and I thought you might want to take a look at that this particular slide is not on the exam but I know a lot of you’re going into the medical field so I wanted to include this for you so you can take a look at that alright nomenclatures of aldehydes and ketones let’s go ahead and start naming these aldehydes are named by replacing the terminal e of the corresponding alkane name with an al ending the parent chain must contain the aldehyde group and the carbon of the aldehyde group is always number one now if the carbon is attached to a ring we actually use a totally different naming system we’re going to see this also when we talk about carboxylic acids so when you’re naming a compound and an aldehyde is on a ring the name is going to change to have a suffix carb aldehyde so we’ll have some examples of that table 19 one in your textbook gives you some common names of aldehydes so on these common names formaldehyde you’re definitely going to see that one before in fact you most likely no formaldehyde more than you do methanol that’s its common name when you have one carbon acetyl aldehyde is also a very common name you need to know that common name and then benzaldehyde on the common name is when you already know from the benzene section so of these common names there’s three of them you are responsible to know and with the systematic name you need to know all of those notice we took off the e ending and put al notice that every time we have an aldehyde this is carbon number one so we do not indicate the location of the aldehyde we know it’s on one it’s understood and then I like this example here where it shows you a carbon-carbon

double bond and that is including the name if you take a look here we have the e right here for protein l and remember this is already carbon number one you cannot have a carbon-carbon double bond between carbon one and two there’s just not enough room so the only place the double bond can go is here that’s why you don’t state where the double bond is and then the common name benzaldehyde you’ve seen before it’s systematic name because it’s on a ring becomes benzene carb aldehyde you’re still definitely able to use benzaldehyde you probably hear that a lot more than you will benzene carb aldehyde but I wanted to highlight the fact that the systematic naming when a Benzie I’m sorry what a aldehyde is on a ring it is named using the suffix carb aldehyde so I have a bunch of names here I want you to go ahead and provide structures for the following it’s best for you to go ahead and pause the video go ahead and draw these structures and when you done come back and check your work all right so take let’s take a look at these we have Penton al is the parent so I’m going to have five carbons in a row 1 2 3 4 5 my aldehyde group is going to be coming off of the number one carbon and the accepted abbreviation for an aldehyde is ch oh it can’t be oh h it has to be h and then oh so be careful with that coming off number two carbon one carbon two would be a ethyl group ch2 ch3 and then coming off of number four remember this is one two three four I would have a methyl group ch3 so checking my work do I have an ethyl off of two yes I have a methyl coming off of four I’ve handled everything I will go in and complete this by putting in the proper number of hydrogen’s this gets one and I know it’s a little sloppy yours oh I’m sure is much neater than mine but I wanted to go ahead and draw this first because most likely this is how most of you did it you have five carbons I tend to put my car but I tend to put my carbonyl group on the right-hand carbon I think it’s because it’s on the end of the name is why I tend to do that I tend to work backwards so what you should have is five carbons and this is carbon number one coming off of two would be an ethyl group and offer for would be a methyl group so I actually want to erase this and I want to show you the same compound but a different version so I know this looks different than the other version but this is a structure I’d like you to go ahead and send draw somewhere else where if someone were to present this format would this throw off your naming it let’s say instead of you given the name and you draw the structure if you were given a structure like this you need to be able to generate the name so what I want you to notice is this is carbon number one no matter what I do the car bonnell carbon of the aldehyde is carbon number one so my longest continuous chain in this case happens to bend around and now i have on carbon one that’s again where my aldehyde is on carbon to do you see this fo group here and on carbon four is my methyl group so the numbering would go in this direction here so don’t let formatting throw you off if someone puts in an unusual format you know the rules you know that an aldehyde the carbonyl carbon is always number one find your longest continuous chain and go from there don’t let formatting throw you off all right let’s take a look at cyclopentane carb aldehyde so did you notice that I have car balda high carb aldehyde as the suffix and that’s because it’s is on e ring so cyclopentane i have my five carbons and i have my carb aldehyde piece coming off of here this is another way it’s acceptable to draw its notice i have the double bond o and then the h next to that so that is another way to draw an aldehyde to naphthalene carb aldehyde so we haven’t seen naphthalene for a while that was back in the benzene section I wanted you to practice how to do a naphthalene carb aldehyde it is on a ring taking a look at my nap fleen remember in this valley part here there’s already four bonds to carbon so there’s no hydrogen’s here so you can’t add anything you can’t put an aldehyde group here this is the first place I can

have something in this case if I wanted in one napthalene carb aldehyde it would be here but this is a two so it’s coming off carbon two so remember on the numbering system on napthalene you don’t count the valley you start off at the peak and then work your way around I also want to remind you that a naphthalene is very symmetrical and so the peak here or here this would be carbon 1 or 11 and 1 here’s 2 and 2 2 and 2 so what could happen if you’re going to have an aldehyde on an appt saline you’re basically if there’s only one on there you’re only going to have either a one naphthalene carb aldehyde or a to nap fling car Bell died right benzaldehyde is one we’ve had before fnl or acetyl aldehyde that’s actually one earlier we saw that you needed to know the common name acetyl aldehyde because that’s what you see more often than ethanal they only have two carbons with my car but with my o.h double bond o and h group here this is carbon number one and pro pinal all right to name ketones we replace the terminal e with Owen II ending the parent chain is the longest one which contains the ketone group so that’s very similar to when we had alcohols remember when we had alcohols it’s whatever direction the alcohol would have the lowest number gave it priority well that’s what’s going to happen also to a ketone so numbering begins at the end near the carbonyl carbon we also have common names for ketones they’re given in alphabetical order with the names of the groups attached and then adding the word ketone so what I want you to do for these four compounds here is to provide the structures for the following this again would be a time for you to go ahead and pause the video filling your answers and then come back and check it all right let’s take a look at this three hexen own one two three coming from right to left I have it coming off of number three also if we take a look at this and we did the common name it would be Ethel’s on this side toples on this side so the ethyl one propyl ketone so acetone is a common name you definitely need to memorize for ketones it’s I you pack name or systematic name is propanone and its more common name is dimethyl ketone but acetone is the one you’re going to know it by more often now I want to mention something about this dimethyl ketone take a look at this name here here methyls on the left-hand side and also on the right-hand side that’s where the dye methyl ketone comes from so the ketone group is this group right in here so when they named this acetone we have commented before that a CET means two carbons well I see three carbons here so what I think happened when they decided to name this common name acetone is they probably figured the ome part here accounts for this carbonyl carbon and the AC et means two carbons one on the left and one on the right not quite sure but I’m trying to reason through why acetone has three carbons again I think the 0 NE is talking about the ketone feature just like in the dimethyl ketone notice this is handled here so I’m pretty sure that’s where that came from alright if you also have a double bond involved remember that the ketone has higher priority so we’re going to go ahead and in this case split up the name the e right here is telling me that there is a double bond starting on number four but what has priority is the ketone so it gets the lowest number that’s why this is a 4 hexen to own because ketone has priority over a double bond and then this last one I wanted to challenge you on what would you do if there’s more than one there did you notice this II came back whenever we have a multiplier in this case it says I have two ketone groups to 0 nes and we did the same thing when we had two alcohols but i have to tell the reader of the name where are they located so the two and the four tell me where the two ketone groups are on a parent chain of six all single bonded there’s a lot of information that one name so when aldehydes and ketones do not have priority we change the name this is known as an acyl group so be sure to add that to your functional groups an acyl group is when you have carbonyl group with our here and then we’re not specifying what’s here if you

remember when we talked about the aldehydes when a hydrogen when a hydrogen was right here remember we call that an acyl hydrogen so that’s the acyl position now the common names when they don’t have priority this is acetyl this is formal and this is benzyl just when you thought you had every name you could think of with benzene they found another one for you so there’s another one benzyl the prefix oxxo is used if other functional groups are present and the EE bonded oxygen is labeled as a substituent on a parent chain the previous pieces up here is when we have this is like the common name like when we had isopropyl remember those that’s when you would use these now this is more of the systematic so take a look at this I I kept this this is from your textbook and I like the colorized of it so what this name does is it assumes you know how to name esters and I know you haven’t been taught that yet so I want you to see that right here is your ester group right here an ester ends in an 08 ending so again even though we haven’t talked about it in the textbook yet you do need to understand a little bit about the naming of an ester group so do you see this piece on an ester we have carbonyl group oxygen and this would be the R group this group right here is this is this piece right here and there is a space there’s no dash no comma there’s actually a space right here so this methyl group specifically this methyl group here is this group right here it’s the right hand side as this ester is written it’s whatever size this is this is carbon number one still and what’s going to happen relative to that this is getting an ester this is carbon number one coming to the left on carbon number three is where I have my ketone and that’s this ox 0 so when the ketone definitely does not have priority it’s known as an ox 0 and then we have six carbons going away from that notice one two three four five six there’s no double bonds I’ll single bonded so that’s how this would work all right so I have both aldehydes and ketones here I want you to go ahead and draw the following pause the video come on back and see how you did all right penta now five carbons aldehyde carbonyl group on carbon number one no substituents just pretty straightforward to Penton own one two three four five it’s systematic name is to Penton own and then it’s unsystematic name is methyl one propyl ketone again I think the two Penton own in this case would be easier to do it’s usually when they’re simpler like even smaller than that that you would go ahead and use the other name with keytone in there cyclopentanone this is when we have a ketone coming off of a carbon in a ring and it’s kind of an interesting thing to draw when you drop for the first time but yeah you definitely just bring those two lines coming out of the corner there and put the oxygen on there here is an example of both an aldehyde and ketone together and I wanted to show you how to do that so what they’ve decided is the aldehyde still gets to be the parent and be carbon number one did you notice the AL ending so I have one carbon here there’s a second carbon here and a third carbon here that’s where the pro pinal comes from ox 0 because my ketone does not have priority is coming off carbon number two so this is an example of when you have both an aldehyde in a ketone together cyclohexane carb aldehyde again keeping in mind when the aldehyde is on a ring the suffix becomes carb aldehyde and the carbon it’s attached to becomes carbon number 13 Penton to own i wanted again to have you practice when you have both ketones are ya ketone feature and also a triple bond ketone has priority over triple bond so with this set i want you to go ahead and generate the names so go ahead and name these pause the video name these come back and check your work alright this first one here happens to be a ketone methyl ethyl ketone is its common name in fact I don’t have it on here this would be to butanone if it had its systematic name but the reason why I didn’t include that is this is one of those common names again just like isopropyl alcohol it’s known as m EK this is a very common solvent and what I think is interesting

is it’s it’s simple name ethyl methyl ketone comes before M but in its abbreviation it’s always mkay so when I worked in industry i use this as a solvent event a bunch and it is known as m EK it’s just not alphabetically correct so just know m EK is ethyl methyl ketone with this one here I’d have that CH three group two times so you know that there’s going to be a substituent coming from here this is an aldehyde I have an aldehyde group on the left hand side this time and a methyl group coming off of carbon number two so it’s two methyl propanol so we have on this next one and aldehyde again and i have my methyl group coming off of carbon number three again remembering that in an aldehyde this carbon on my carbonyl group is always carbon number one so down here i have a cyclo ketone and remember the carbon right here is going to be carbon number one because it has priority and you go in whatever direction that causes the chloro to have the lowest number three chloro cyclohexanone to bromo benzaldehyde or we can remember we can use the ortho system on here because there’s just two things on a benzene ring so it could be either to bromo benzaldehyde or ortho bromo benzaldehyde and here we have another the hide with a double bond to penty now remember the aldehydes understood to be on carbon one relative to that the double bond starting on carbon number two preparation of aldehydes and ketones the best method of preparing aldehydes and ketones is alcohol oxidation primary alcohols are oxidized to give aldehydes and PCC and dichloromethane is usually chosen for making aldehydes now my general reaction here I do have a primary alcohol normally you wouldn’t draw the primary alcohol with explicitly showing all these bonds but the other thing that I’m showing you in this general reaction is we’re going from an sp3 hybridized carbon to an sp2 hybridized carbon so that’s the reason to show this you normally would not have to show all these explicit hydrogen’s and all that normally you would just write it as a condensed structural formula so the best way to make an aldehyde is to take a primary alcohol PCC and I can make the aldehyde don’t forget you still also need to put the dichloro here the ch2cl2 so primary alcohols are oxidized give aldehydes secondary alcohols are oxidized to give ketones and we can go ahead and use PCC we can also use CRO 3 and the sodium chromate also are all effective for making ketones so in this case I have a secondary alcohol again I’m explicitly showing you this to show you guys from SP 3 2 sp2 and again we make a ketone we are going to see this reaction a bunch as the semester goes along in fact right now we’re taking a look at making aldehydes and ketones and when we were back in the alcohol section we actually talked about primary alcohols reacting to make aldehydes well now we’re looking at how r aldehydes mate so this is the same reaction you saw before same thing with secondary alcohols we can make ketones well now we’re looking at from the viewpoint of how do you make ketones so these are the reactions these kind of reactions we’re going to see again and again all right we can also now this is another reaction we can reduce an ester and we can go ahead and make an aldehyde so this right here is die isobutyl aluminum hydride di bah so instead of writing all of that we get to use the initials they’re also using toweling and negative 78 degrees C that’s the first step the second step is a protonation so we’re going to be making an aldehyde out of this and this is a reduction so if you keep in mind a reduction reaction means you’re going to have less bonds to oxygen so what do you predict the product is going to be with this reactant with this reaction what’s going to happen is this o R is going to become an alcohol and then we’re also going to make an aldehyde so the breaking point is going to be right there we’re going to make less bonds to

oxygen so this is a reduction reaction so not only do we get an aldehyde but we actually also get an alcohol out of here don’t forget ROH is an alcohol just written in the reverses where you were used to all right we can go ahead and make ketones with ozone alisis of alkenes now we do have a condition that has to happen it says if one of the life one of the unsaturated carbon atoms is died substituted so this goes back to last semester it’s reviewed you can review this again in Section 7.8 and what’s going to happen is we have two hydrogen’s here so this is going to be unsubstituted as die substituted and what’s going to happen is this ozonolysis it’s basically going to form a cleavage reaction where it’s going to break this right here it’s going to cut it right here so we can get a ketone here and technically not only depending on what’s going on on this carbon here in this carbon here we actually also got an aldehyde out of that but this is focusing the way they are wording this is they’re focusing it on making a ketone but again depending on this cleavage reaction what’s on the left or the right you might get to ketones and aldehydes ketones be sure to review section point eight to see the specifics of this reaction another way to make a ketone we learn this back in section 16.4 is a friedel-crafts isolation of an aromatic ring aluminum chloride in the presence of some heat so go ahead and I would pop have you pause the video and go ahead and write the product on this you’ve seen this one before so hopefully you remember that pretty well and there we have friedel-crafts isolation the connecting point is where the halogen was and we also have the hydration of a terminal alkyne in the presence of a mercury catalyst to make a ketone this is again a terminal alkyne make sure you keep that in mind it must be on the end and what we actually get is a methyl ketone out of it and this is a reaction we have back again in Section eight point six so you can go back to that section if you want more detail on this and this is a functional group methyl ketone and if you remember we saw some methyl ketones a lot only talked about mass spec we saw a lot of fragments of metal ketones so I have complete the following reaction the first two of these I want you to prepare the following product from the appropriate alcohol erythroid form instead of from all right so you need to change that too from for me since I’m already recording this it’s going to be stuck like that all right so here’s the name of the product that I want and the reaction is going to go here so I want you to go ahead and use the appropriate alcohol to form these two so the best way to do this is to start at the end give me the structure of the product first so that’s penta now and the appropriate alcohol would be wherever this carbonyl oxygen is that would be beat that would become the o H group but keep in mind i would have to have two hydrogen’s here instead of one so carbon has the correct number of bonds and i know i’m going to go from an alcohol to the product so i need to find some reaction conditions and we saw earlier what different with different oxidizing agents so pcc CH 2 CL was one of them so go ahead and this happens to be a ketone go ahead and use the same format for this right down the product right down the reactant and then the conditions that it needs to have in this case there is actually three different ones in there that I could have used so keep in mind wherever the carbonyl group is that’s where the 0 H group is and then in this case you could have picked one of three I just picked one of them so go back and check in your notes three different agents you could use for that all right so for the rest of these go ahead and complete the following reactions pause the video and I will come and come on back and check your work alright for this first reaction here what’s going to happen is this is an ester and what’s going to happen is we’re going to break the bond right here I put the oxygen on the left hand side this time instead of the right hand side still an ester and this piece right here is going to become an alcohol and this other piece here is going to become an aldehyde this next one here is ozone alisis we’re basically going to cleave this right here and we’re going to get out of it a ketone and in this case also

formaldehyde letter E is going back to our freedoms crafts and my our group happens to have ch2 ch3 so I made sure I added that the connecting points where the halogen is this last one here is going to make a methyl ketone this is going to be the case where I have a terminal alkyne it’s going to form a methyl ketone how do you do oxidation of aldehydes and ketones ketone are usually unreactive towards oxidation and this reactivity is a consequence of structure aldehydes have a hydrogen or a proton that can be removed during oxidation that ketones do not ketones are inert to most oxidizing agents but can undergo slow cleavage reaction when treated with hot apple and potassium permanganate the reaction is practical for cleaving symmetrical ketones so one of the things we’re going to do is when we in lab we can actually do an oxidation reaction if we have a compound and we know it’s either now the hide-a-key jumper we’re not sure which one it is we can use an oxidation reaction to identify it as either now the height or ketone so we’ll be seeing some of those reactions also those will be qualitative so this is the one reaction that is undergoing an oxidation of a ketone and I happen to pick a symmetrical ketone in this case well it is a symmetric with ketone but at one on a ring this is the potassium permanganate so what you want to do with this and what helps me as I count my carbon so if you take a look here carbon one two three four five six it’s going to break here this is carbon one two three four five six if you’re going to break up a ring make sure that you don’t give me too many carbons on the side that this carbonyl group here and this carbonyl group here is going to be only six carbons total don’t add more carbons on there so one of the ways that I do that is I go ahead and make myself some notes here and number them so this is the reaction of a cleavage reaction treated with hot / TAS IAM permanganate this is one of the reactions that happens there aldehydes are oxidized to the corresponding carboxylic acid so we have our carbonyl group here this is an oxidizing agent and notice it’s converted to a carboxylic acids now this is hex now this is an example out of your textbook so it actually gives you more reaction conditions so I give you some basic conditions here but you do need to know that you have to have some acetone and this is happening at a cold temperature so be sure to add this part here to your reaction conditions this is a general reaction this is a more specific so be sure to include that and what’s going to happen is I’m going to form a hexanoic acid again you haven’t learned how to name carboxylic acids but I’m sure you can see what happened was the AL ending for aldehyde becomes an acid ending when you have a carboxylic acid so one of the most common reactions you’re going to do in an organic lab as a tollens test you’re going to make a challenge reagent and this is a qualitative test for aldehydes so when someone says something is a qualitative test that’s a visual you’re going to get a nice dramatic change that you can see during the reaction to see the changes of the before and after so if they say it’s a qualitative test for aldehydes then that means a reaction change means that is an aldehyde so qualitative test for aldehydes means yes you have an aldehyde if you see your reaction so they wouldn’t for example call this a qualitative test for ketones because ketones do not react that’s why it’s a qualitative test specifically for aldehydes so one of the simplest methods for oxidizing an aldehyde is you use silver ion in dilute ammonia this oxidation produces a shiny silver metal mirror deposited on the walls of the reaction flask so I have a picture of that over here so you’re going to be doing this in class you’re going to actually take tollens reagent and you’re going to see a silver mirror formed in your test tube and this is how they used to make mirrors so let’s take a look at the reaction you have an aldehyde we have silver with our oxygen and we also have in here dilute ammonia water and ethanol so there’s a lot of reagents that go a lot of pieces that go into making a tollens reagent in fact in lab you’re going to be making the tollans reagent fresh and then using it so it’s this hydrogen right here the the acyl hydrogen that is going to be

replaced with an O age group it’s going to make a carboxylic acid but the other product is the solid silver and that’s what’s deposited on the wall so that is a qualitative test or positive test for aldehyde now because this is an awful lot of stuff to write Anton’s test is so commonly used a lot of times instead of writing all this information they were just put silver plus because it is an ion and Tolan solution instead of writing all of this stuff so if you want to write the abbreviated version make sure you have silver plus on the left-hand side but silver solid on the right-hand side that still needs to be included in your reaction if you want to write it that way so this is a read this is an oxidation reaction because notice this starting carbon here in my aldehyde has two bonds to oxygen and over here is a product it now has three so this would be an oxidation reaction remember aldehydes undergo oxidation because of this hydrogen right here that can leave ketones don’t have that there’s a carbon there so aldehydes undergo oxidation and ketones do not another oxidation reaction of aldehydes is to use what’s called Jones reagent so Jones reagent has the CRO 3 sulfuric and acetone so again instead of writing all this stuff with the arrow which they can do sometimes they’ll just write Jones reagent and again it’s an oxidation reaction where this hydrogen becomes an o H group now the Jones reagent I want to mention this Jones reagent doesn’t give us anything any kind of change so it’s not a qualitative test the Jones reaction is simply just taking our aldehyde to carboxylic acid because maybe we want the carboxylic acid instead so keep in mind Jones oxidation Jones reagent is not a qualitative test again I now have a second qualitative test and this is Benedict’s reagent so we have tollans that’s a qualitative tests for aldehydes we also have been free agent that is a qualitative test for aldehydes so what happens is you get a red precipitate of copper oxide and this tells us whether we have an aldehyde or not so the reaction here we start off with a copper two-plus solution we get a copper one solution the beginning copper two-plus is actually a blue solution and when it undergoes its reaction to become copper one it becomes a red precipitate so this is a nice qualitative test to tell us whether or not we have an aldehyde so again qualitative tests tell us yes or no if its present vs jones this is also an oxidation the other two oxidation but all we’re doing is converting it from one to the other because we want to use it for something else we’re not actually using a qualitative test alright time to put what you learn in to practice predict the following product or products for the following go ahead and pause the video come on back and check your work ok to start this off one of the things I like to do is see what compound i’m working with this first one here is an aldehyde this is an oxidation reaction and I know aldehydes undergo oxidation so yes this will form a product and the products going to be this H here is going to become an o H and I’ll have a silver mirror so solid silver all right this is Jones reagent Jones reagent is an oxidizing agent this is an aldehyde and aldehyde will undergo an oxidation reaction and what’s going to happen is and this is a line structure I wanted you to practice that what happens is you end up getting an o H here and notice you have to draw that line there because it’s an understood h-here that becomes an o H so I wanted to also present a line structure to you so you can practice those and then in letter C this is a ketone and this is Benedict’s solution which is an oxidizing agent this is a ketone ketones do not undergo oxidation so you should not have written a product it should be no reaction

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