In this video we're going to talk about lesson 7 which is chapter 12. We'll talk about alcohols, phenol, stiles, and ethers or ethers. So let's talk about first about alcohols. So you've seen alcohols here and there. We're going to focus more on their reactions, their names, and how to classify them.
So how do you control? You have an alcohol, you have an organic compound containing an OH which is called a hydroxyl group. Attached to an alkyl group, alcohols have the uniformity of R-OH.
And this is called a carbonyl. The carbonyl is the carbon attached to the alcohol. So alcohols, depending on the number of alkyl groups, attach to the carbonyl carbon. So again, the carbonyl carbon is this carbon.
Are classified as either primary, secondary, or tertiary. Now here's a trick. When you look at the carbon and the OH.
The difference of what makes it primary, secondary, or tertiary, and this is really, really important because it's going to dictate a lot of our reactions, is how many carbons are attached to the carbonyl carbon. And again, the carbonyl carbon is this one right here. It's the carbon attached to the OH, right?
So if there is only one carbon attached to that carbonyl carbon, then there's a primary alcohol. So the other two are H's. And so one of the bonds goes to the OH, two of the bonds goes to H's, and one of the bonds goes to carbon. So that makes it a primary alcohol.
A secondary alcohol is attached to two carbons. So our carbon that has the OH, so our carbonyl carbon, is attached to two other carbons and to only one hydrogen. And a tertiary carbon is attached to three carbons, no hydrogens.
So here's an example. Classify each of the alcohols, and we're going to do primary, secondary, or tertiary. So find the carbonyl carbon, so the carbon with the alcohol.
So that's this one. And that's going to dictate whether this alcohol is primary, secondary, or tertiary. So look at it, and look at how many carbons are next to it.
So this one has two carbons next to it, so that's a secondary alcohol. If we look at find the next one. So here's my carbonyl carbon. This is the one attached to the OH. And count how many carbons are next to it.
1, 2, and then 3. So this is tertiary alcohol. Alright next one. Find your carbonyl carbon.
This is the one that's attached to the OH. And count how many carbons are right next to it. 1. So this is the primary alcohol.
And then this one, find your carbonyl carbon and count how many carbons are attached to it. One, two, so this is a secondary alcohol. Some physical properties of alcohols.
Alcohols are very important to us because of these physical properties. So it has a very similar structure to water. The hydroxyl group, which is this group right here, is very polar.
Very polar. It has the ability to form hydrogen bonding. So if you recall, hydrogen bonds are the stronger type of intermolecular forces between two molecules. Because of this, they have high boiling points relative to their molar masses due to the ability to hydrogen bond. So hydrogen bonding will make it harder for us to break those intermolecular forces.
So we're going to have higher boiling points. So for example if you take propane and then you take ethanol and they both have very similar molar masses. Propane has a boiling point of about negative 42 degrees Celsius while ethanol has a boiling point of about 78 degrees Celsius. So that's a big difference and this is because the strongest intermolecular force here, this is nonpolar, so the strongest intermolecular force here London dispersion force which is a very weak intermolecular force and the strongest forces ethanol can form with another ethanol is hydrogen bond which is very strong intermolecular force so if you bring another ethanol right this is gonna require more energy to break than this London dispersion force right here this is also why propane is a gas at room temperature and ethanol when you're in the cooler room temperatures. Room temperature we say is 22, 25 degrees Celsius.
So ethanol is going to be a liquid at room temperature. So solubility of alcohols with low molar mass. So alcohols with 1 to 4 carbons are soluble in water. They tend to be very polar. because they're so small they're very polar and they're soluble in water because polar attracts polar like dissolves like hydrogen bond with the water molecule they are hydrophilic the word hydrophilic means are water loving so alcohol is really like water as the number of oh groups increases the polarity and the water solubility of the alcohol increases as well so for example there's a space here remove that space so this right here is called a dial because there's two OHs, this is very soluble because it has more OHs and makes them more soluble.
And as molar mass increases, so as they get bigger and bigger and bigger, alcohols become insoluble in water because there are more carbons than there are OHs. The OH is what makes it polar and what makes it soluble. But if you increase the number of hydroxyl groups, then you're going to increase solubility.
So something like a diol. which means that you have two OH groups, or a trial, which means you have three OH groups, are more soluble than those with only one single hydroxyl group. So what this is saying is that something like this versus something like this, this is going to be more soluble right here because it's more polar.
So the more OHs we add, the more soluble it's going to be in water, and the more polar it's going to be. So how do we name them? We're going to use IUPAC rules, and we're going to do it based on the longest carbon chain containing the hydroxyl group.
You're going to take the E ending, so notice that it's not the A-N-E, it's just the E at the end, and you're going to replace it with O-L. The chain is number from the end, given the hydroxyl group, the lower number. So if you have hydroxyl versus methyl or a... Chloro or halogen the hydroxyl is going to take priority the number indicating the position of the hydroxyl group is Inserted just before the OL and I might need two ways to do this You can do it in the front like we did with double bonds You can go to the front of the parent name or you can do it in between the parent name and then for cyclic Alcohols the OH is going to be a carbon one. So we don't tend to number them you can it's not very common So because we know the OH is a carbon 1, we tend to not number it unless there's other reasons why we have to.
So let's write the name for it. So find your longest parent chain. You could have done this one as well.
And then count to give the OH the lowest number. So you could have gone 1, 2, 3, 4. And you could also do 1, 2, 3, 4. We're going to give the OH the lowest possible number. So then this group is called 3-methyl and this would be 2-O.
So the name of this is 3-methyl and I'll write it like your book once you write it first and then I'll show you the way that most of us do it. So four carbons will be butane, so butane and then dash, 2-O. So instead of writing butane, I get rid of the E and write the possession of the alcohol.
Or you can write it like this. You can do 3-methyl-2-butanol. Let's try another one. So this one says cyclic.
So this is cyclohexane. And we have an alcohol here. And then we have a methyl group here.
So we're going to name this carbon 1, carbon 2, carbon 3. So this is 3-methyl and it's going to be cyclohexanol. Now sometimes you can see it with the 1 indicating where it is, where the alcohol is. But because we know that if we don't see a number that's carbon 1, sometimes we don't, most of the time we write it like this. But very few times you will see it like this, but it's more, this is the more correct of the two. And then because of this, you can also write it like this.
Cyclohexan1. But again, this is kind of redundant. So we just do this one right here.
But I'm just showing you this too because sometimes you do see them that way. Not very commonly. I think there's one example here from a book. that does that but this is the preferred way for you to do it there are a couple common names for alcohols that you should be able to recognize uh you have this one right here let's start with this one so this if you notice it looks like this when you draw it skeletal right this is called isopropyl alcohol And then you have this one right here that has four carbons and they're in the shape of a T. So we call this T-butyl alcohol.
So those are some common names of alcohols that you may see. All right, let's practice. So question 12.1 says draw the structures for each of the following alcohols.
If you want them, you can do the condensed or you can do the structural. I'm going to do the skeletal. but it's up to you as long as we get something similar so we are going to do two methyl propane one oh so probe is three one two three don't forget to count one two three and in carbon one we have an alcohol and in carbon two we have a methyl if you did it in the condensed format do your carbon first So, do C, leave some space for your hydrogens, and in carbon 1 you're going to put an OH, and in carbon 2 you're going to put a methyl, and then just fill in the hydrogens that are missing. So this has two bonds, so it's missing two hydrogens.
This has three bonds, so it's missing one hydrogen, and the last one is missing three hydrogens. You could also, if you want, if it's easier, Just write it out fully. So give everything four bonds because there's no double bonds.
In carbon one, we put a hydroxyl group. In carbon two, we put a methyl and then HS and the rest of them. Notice CH3, CH3, CH, CH, and CH2. You should be able to do any of those.
And also you should be able to condense this further. So if we want to condense this further, we write CH3, and there's two of them, attached to the same carbon, a CH carbon. And then next to that is CH2, and then NOH at the end. That's another way that you can write that.
All right, let's do the next one. So this is... two chloro cyclopent 1-0 so that's what i was telling you sometimes your book does use the one but if i don't see the one which is more common not to see it it just means that it's in carbon one but your book likes to add in all right so there's my cyclopent so five carbons in a ring and then carbon one is going to be my alcohol and carbon two is gonna be my chlorine all right next one and by the way when i say amid you can omit the one that's only for cycle alcohols right two four dimethylcycohexanol so cyclohexanol and then we're gonna do with carbon one we do the oh carbon two and four iron methyl so that's carbon 2 then carbon 4. Alright next one 2,3-dichlorohexane 3-O or 2,3-dichloro 3-hexane O this is 1, 2, 3, 4, 5, 6, 1, 2, 3, 4, 5, 6 And then in carbon 3. Which it doesn't matter which way you start.
You can start here or you can start here. In carbon 3 I'm going to put an OH. That's an OL.
And in 2 and 3 I'm going to put a chlorine. So I'm going to put a chlorine here. And then a chlorine here. And then I'm going to rewrite it because it will make me feel better. You don't have to.
So it will be OH. and yeah so a couple of medical important alcohols that you may see the first one is a methanol and meth means one carbon so it's one carbon with an oh and the rest of them are hydrogens after we're in this ch3oh sometimes you you may see me write it as M-E-O-H. That means methanol as well.
So this is a shorthand notation for writing the word. And this is only when we're talking about it in like a chemical reaction. And I don't want to write, you know, C-H-3-O-H.
Sometimes you'll see this, the same with ethanol. I'll show you the one you may see for ethanol. It's not one that I want you to write.
It's one that I want you to recognize. Things about methanol that we like is that it's colorless and it's an odorless liquid. It's used as a solvent, so it's very good at dissolving nonpolar compounds.
Now, the problem with methanol is that it's toxic. It can cause blindness and death if ingested, and it also can be used as a fuel. The next one that we're going to talk about is ethanol. So, eth means two, and ol means alcohol. which we can write like this a lot of times you'll see it like this and sometimes you see it like this e-t-o-h so this is also an utterless and colorless liquid it is widely used as a solvent again we use it very heavily the alcohol and alcohol beverages derived from fermentation carbohydrates is ethanol and if ever produced it varies with the starting material and the fermentation process next one is propan 2-ol which is isopropyl alcohol which looks like this so C C C OH CH 3 CH 3 and then H doesn't fit Other times you'll see it in skeletal structure like this.
So this is other times what's in rubbing alcohol. Sometimes it's more like a diluted version of this. So commonly called rubbing alcohol, colorless but has a slight odor, toxic when ingested, it can be used as disinfectant and as industrial solvent.
Next one is ethylene glycol. And ethylene glycol is ethane 1,2-diol. So it looks like this. Diol means that you have two alcohols.
And then the rest we fill with hydrogens. This one you most commonly see it in a skeletal form. or just name its name ethylene glycol so this one is used in automobile antifreeze it has a sweet taste please don't taste it but that's what it tastes like and it's extremely poisonous and that's why you should not taste it because it is extremely poisonous we normally add to water to lower the freezing point or raise the boiling point of it so that's why we use it in our cars in our antifreeze our next one is one that you're gonna see a lot our biochem unit which is glycerol so glycerol which is glycerol looks like this is propane 1 2 triol so three OHs and then H H H H H a lot of times you'll see it written this way Just because of the way we bonded on the Zell's should be a CH woman You can also skeletal dry it. But this is probably the most common way that you will see glycerol. It is very viscous, very thick, it has a sweet taste, it's non-toxic, it's highly water soluble, it's used in cosmetics, pharmaceuticals, lubricants.
If you have... a lot of your makeup if you wear makeup will have glycerol in it and glycerol is obtained as a byproduct of fat hydrolysis which we'll talk about in a little bit so let's talk about the reactions involving alcohol so if you have your handy dandy index cards this would be the great time to pick them out so you can add things to them so the first reaction we're going to talk about is actually one that you've seen and some of those ones will overlap with ones that you know and nuance this one should be a review so this one is hydration and this is how we prepare an alcohol prepare means that we're making an alcohol so how do we do this how have you seen a hydration you have seen an alkene plus water and then acid catalyzed will give you an alcohol if you take an alkene let's call those ours because we don't know what they are. It could be aryls, alkyls, it could be hydrogens. And then plus water.
And then we need acid, some sort of acid. Let's use a pure gas. It's one of the easiest ones to use. Theoretically easy ones.
And the lab's not so friendly. So you have to be careful with it. And then R, R, R, R. And then this is H. And then no H.
And remember Makarnikov's rule, the major one, so the OH is going to go in the carbon with the least amount of hydrogen. So it's called the more substituted carbon. So you want to get a higher degree of an alcohol. So between a primary and a secondary alcohol, the secondary is going to be the major product. Between a secondary alcohol and a tertiary alcohol, the tertiary alcohol would be the major product.
Alright, the next reaction is called hydrogenation and this one is new. So make sure you add it to your index course. So in this one, we're going to take an aldehyde or a ketone and across a carbon to oxygen. This one's a carbon to oxygen. You're going to add hydrogen.
So here's my carbonyl, so my carbon and oxygen that we'll bond. And then there's going to be R and then there's going to be R. So this R is special because if it's an H.
that's an aldehyde and if it is an alkyl or aryl group so like a ch3 a ch2 ch3 then that's going to be a ketone and then to this we are going to add hydrogen and when you add hydrogen don't forget that you need a catalyst we're going to do platinum lead or nickel i'm going to do platinum and then what's going to happen is the c o will open and here you're going to add hydrogen and here you're going to have it looking like when you want to open a double bond a carbon carbon double one we're doing that we're opening this double one as well and this is r and this is the other r in here so that would be your alcohol so this could be an aldehyde or it could be ketone depending on what this r is and then you add hydrogen and then a catalyst and that will give you your alcohol. Another new one is called dehydration of alcohol. So in this one we're going to go backwards. We are dehydrating it. When you are dehydrated it means that you're missing water.
That's what we're doing. We're removing water from an alcohol. Alcohol is dehydrated with heat.
in the presence of a strong acid so we need heat and we need a strong acid so we need two things for this one to produce alkenes in water dehydration is a type of elimination so we've done addition reactions so we're going to do an elimination reaction so here the oh and the h are removed from the adjacent carbon atoms they're going to produce an alkene and water and this is the reversal of the hydration reaction that forms alcohol so this is the reversal this reaction right here. So we're going that way. Alright so let's look at it.
So we need an alcohol and our idea is that we're trying to get an alcohol into an alkene. So my alcohol I'm going to do R, R, and then we're going to do H, N-O-H, right? So we need, this has to be either a secondary or a primary alcohol because you have to be able to remove a hydrogen from next to it. And then to this, what we're going to do is we're going to apply acid and heat. And you're going to get C double bond C, R, R, R, R. And those R's can be hydrogens or they can be carbons.
And then plus water. Don't forget that water is H and OH. That's what water is. Now, you're going to hear this a couple of times. I don't know if I've talked about this yet, but just so you aware.
This is a major product. This is the main product that we form. Water is called a byproduct.
So a lot of times you'll hear the word byproduct. It just means that you're also producing it, but it's not the main thing that you're concerned about. Now with this one, with the formation of the alkene from alcohol, we have to follow a couple rules.
And the first one is called Save-Says Rule. So just like we follow McCartney-Cobb's Rule when we're forming the alcohol, we're doing Save-Says Rule when we're forming... the alkene from alcohol. So some alcohol dehydration reactions are going to produce mixture and this depends on which carbon has the greatest amount of hydrogens. So what you're going to do is your double bond is going to go to the least.
So double bond is going to be placed towards the least amount of hydrogens so it's the carbon that has the least amount of hydrogens right or like the rule itself says with the greatest number of alkyl groups and alkyl groups are ch2 ch3 and then so on so whichever way you would like to look at it right so here's what this means So I would ignore, actually let's ignore this one because I like this drawing better. This drawing does a lot better at showing you. So this is going to give you two products.
It depends on which hydrogen you're going to remove. So you have two choices. You can remove those two and form a double bond here or you can remove those two and form a double bond here.
So let's form it. So if we remove those two then that will give me double bond here and then H H H if we remove those two if we eliminate and let's call elimination double bond goes here right so we remove those two and make a double bond here then one of them is going to be your major product one of them is going to be your minor product And the major product is going to be where the double bond is attached to the carbon with the least number of hydrogen. So if you look at this carbon, this one has two hydrogens, three hydrogens, three. And if you look at this carbon, this one has two hydrogens.
So Saves-Rules rule dictates that the double bond is going to be right here for the major product. This is going to be major. This is going to be minor.
So it's we want the double bond. So it always has to start where you remove the OH, right? And then again, we could have drawn it here, we could have drawn it here depends on if they're not symmetric.
It depends on which carbon has the least amount of hydrogen. This one has two hydrogens, this one has three hydrogens. So we draw the major products going to be here, it's more stable. And that's why I choose this because the double bond becomes more stable so it's going to hide it in there let's number it let's label it name it one two three four this is one butene and this is going to be one two three four so this is two butene let's double check ones really quick one two three four one two three four one two three Just double checking.
Okay. Let's try this question. It says, predict the product of dehydration.
What are the major and minor products when 3-methylbutan-2-ol is dehydrated? So my recommendation is let's drop this one out. And then in carbon-2, there's an alcohol.
If you want to make this your carbon tube, that's fine. It doesn't matter. I'm just in the habit. The way I would start organic chemistry was to always try to draw it from right to left. But if you want to do it left to right, that's fine.
And then when three methods right here. Okay, and let's fill it out. So then we're gonna write the reaction so it's gonna be not plus we are dehydrating so I need an acid and I need heat so for the first one so here's my OH this OH is gonna get removed and I'm gonna remove this one here and make a double one double one and then I'm gonna do the same thing but in this case so here's your age I'm gonna move it the other side so they have to be neighboring by the way I can't take this one right here can't do that they have to be neighboring right next to each other and I'm going to make my double bond right here right and then plus water now we have to figure out which one is the major which one is the minor so this one has three hydrogens this one has one hydrogen so this one right here the double bond between those two is going to give you the major product it's going to be your major product this is going to be your minor product Let's name it. I'll fix my double bond because it looks like an equal sign. All right let's practice naming.
So I'm going to go one two three four so this is 3-methyl-1-butene. And then the bottom one is going to be 1, 2, 3, 4. And this one is 2-methyl-2-butene. Okay, so the next reactions that we're going to talk about, again, I feel like I say this a lot in this chapter, but these are very, very important. You're going to see these ones a lot. We're actually going to see them again in the next chapter as well.
So this is going to be the oxidation of alcohols, depending on the type of alcohol you have, depending on the type of oxidation that you have. So that's why it's important for you to be able to recognize primary, secondary, or tertiary alcohols. So if we take a primary alcohol, we can usually oxidize them to carboxylic acids.
Now, this is going to be a two-step kind of thing. You can oxidize it to an aldehyde, and then we would oxidize it to a carboxylic acid. So...
what we're going to use is we're going to use the symbol right here to indicate oxidation and what is happening is because there's a lot of things that we can use to oxidize and one of our miles and we're very strong we use this right here right so some examples that you may see you may see potassium permanganate with hydroxide or you can see chromate like chromic acid chromates are really good oxidizers and what they're going to do is they're going to oxidize a primary and this is very important alcohol to an aldehyde and then to a carboxylic acid so you can take your primary alcohol oxidize it with something mild to an aldehyde and then oxidize it again to a carboxylic acid So we're going to take our primary alcohol and I know it's primary because the carbon that is attached to the OH only has one more carbon next to it so we're going to call it R but it has two hydrogen. So it has to be and it has to be a primary alcohol and we're going to oxidize it and the first time we oxidize it or if we oxidize it with something mild then that's going to give me an aldehyde which looks like this and if we oxidize it if we have or we have something stronger something stronger will just go all the way to carboxylic acid so this is usually if you have something mild or if you oxidize against aldehyde then you get carboxylic acid. So here's an example. It says write an equation showing the oxidation of 2,2-dimethylpropan 1,O to produce 2,2-dimethylpropanol.
this is an aldehyde so let's do prop means 3 1 2 3 and carbon 1 we have our alcohol and I'm missing stuff 2 comma 2 dimethyl no yeah 1 2 3 And we are going to oxidize it to make an aldehyde. So we're going to stop here. And there's your aldehyde. If you want, you can add the H here if you want. But that's your aldehyde.
So that's 2,2-dimethylpropanol. So notice the difference between the aldehydes and the alcohols. It's just one tiny letter difference in the naming of them. Now, what if you have a secondary alcohol?
Very different reaction. You're going to get a very different reaction, so you have to be careful. Secondary alcohols are going to give us ketones.
So a secondary alcohol, actually, I'm going to do it a little bit different. And we're gonna oxidize it. So this is a secondary alcohol and what you get is you get a keto and So it eliminates two hydrogen's illuminates this hydrogen and this hydrogen and you get your ketone but this is the main thing that we're concerned about is our ketone now very very very importantly tertiary alcohols do not undergo oxidation reactions they don't have the ability to eliminate the two hydrogens that are required to do it okay so they can't do it they absolutely cannot do it so tertiary alcohols cannot undergo oxidation reactions so tertiary alcohols do not oxidize There's no hydrogen in the carbonyl carbon to remove. So not possible. So how do I know it's tertiary?
My carbon is attached to three other carbons, the carbon that has alcohol in it. And if you try to oxidize this, absolutely nothing happens. So what we write is we write NR.
NR means no reaction. So one of those ones has to be a hydrogen, at least one of them, for us to be able to oxidize it. Now let's practice.
So let's predict the name and product of the oxidation of. We're going to do 2-butanol. 2-but is 4 and 2 is OH right here.
And we're going to oxidize it. We're actually not going to name it yet because we haven't talked about aldehydes and ketones, but we are going to predict it. So we should be able to predict it and predict what type of compound it is.
So you should be able to tell me, oh, that's an aldehyde. Oh, that's a ketone, right? So this secondary alcohol is going to give me secondary alcohol oxidized to make a ketone.
This is a ketone. We're not going to name it yet. Alright, let's draw this one right here.
Actually, we can use this one, so we can practice using condense. We're going to oxidize this one. And this is primary.
So this is a primary alcohol. And what that's going to give us, this is going to give us an aldehyde. and then this can oxidize further into carboxylic acid.
So this is an aldehyde and if we have a very strong oxidizer we can go all the way to a carboxylic acid. So notice something important that I removed one hydrogen from here and this hydrogen to be able to form this. And then to go from an aldehyde to a carboxylic acid, I removed the H and I made it OH. Alright, what about this one?
So 2-methyl-2-pentanol. So let's do it. Pent is 5. 1, 2, 3, 4, 5. 2-methyl. OH and this is a tertiary alcohol is a carbon attached to three other carbons so the carbon has a hydroxide is the one we care about and this is tertiary alcohol so there's that mean no reaction we cannot oxidize a tertiary alcohol there is no hydrogen that it can have for it to be able to go through the oxidation So oxidation and reduction in limit systems you'll see a lot.
Oxidation is the loss of electrons. Reduction is the gain of electrons. We can also do it in terms of oxygens and hydrogens.
So these changes are easily detected in inorganic systems with the formation of charged ions. In organic systems it is often difficult to determine whether oxidation or reduction has taken place. So the easiest way to do it is by oxygens or hydrogens. So in organic systems, we're looking at what's happening with oxygens and the hydrogens. So if it oxidizes, it means that it gains an oxygen or it lost hydrogen.
And that's what these ones are doing right here. This one is losing those hydrogens. And the reduction is the loss of oxygen or the gain of a hydrogen.
So from the least to the most oxidized. So an alcohol is the most reduced version of it. And then carboxylic acid will be the most oxidized version of it. You can also see this in biological systems with something like forming NADH+, which is a coenzyme commonly used in biological oxidation or reduction systems. So here's your alcohol.
And we can take this alcohol and the question becomes what kind of alcohol is this? Primary, secondary, tertiary. So this one is a secondary because it's a carbon attached to two other carbons.
So secondary alcohol. So what is the carbon with the alcohol attached to? So secondary alcohols form what?
They form ketones. See, this is where Orgo comes in play. We can deduce what is going to happen based on what we're going to, and this is oxidized right here, and it will form NADH.
Next type of alcohol that we're going to talk about, you've seen a little bit of it, it's called Afino. compounds in which hydroxyl groups attached to a benzene ring there tend to be polar compounds due to the hydroxyl group simpler phenols are somewhat water-soluble components of flavoring and fragrances is what we use them for and they have the formula if we're gonna short it we do this this is a benzene ring actually technically AR stands for aromatic but if it's a phenol the phenol is a phenol is just as if it's just one simple phenol and I can't not draw a hexagon today. And then from here we can derive other compounds and they're widely widely used in healthcare as gemacidin, antiseptics, disinfectants.
So here's some examples of what phenol derivatives look like and most of them can be used as antiseptics. So you may see them if you are working with antiseptics. My next group that we're going to talk about is ethers and ethers are the formula of ROR.
And R can be aliphatic or aromatic. Aliphatic is the alkyl groups. So it's H3 and ethyl and methyl.
It could be acyclic ring and aromatic, benzene, things like that. Ethers are slightly polar due to the CO bond. So that oxygen right there.
Make sure that you remove that carbonyl. This does not have carbonyl. They do not hydrogen bond because there are no OH groups. So they cannot hydrogen bond.
And ethers have much lower boiling points than alcohols due to the lack of hydrogen bonding. There's a couple ways that we can name. ethers. There's the common name and there's the IUPAC name.
For the common names, all you're going to do is you're going to alphabetize the alkyl groups and write the word ether at the end. So for example, alkyl group, alkyl group. So this is two methyl groups. So we call this dimethyl ether.
This one, we have a methyl and an ethyl. So we do alphabetically. We do ethyl. methyl ether next one we have this right here which is an ethyl and this right here which is an isopropyl so this will be ethyl isopropyl ether if it helps you dry it out so this will be like this so here's your isopropyl so ethyl isopropyl ether but you can also use the IUPAC nomenclature and you're gonna have to use actually for the ethers you're gonna have to use both of them so for IUPAC nomenclature what we're gonna do is They're based on the alkane name of the longest chain attached to the oxygen. The shorter chains are named as an alkoxide substituent.
So the shorter ones, notice there's a long one here and a shorter one there. So the short one is going to be replaced by oxy. I want you to call it oxy, like methoxy, ethoxy.
So for example, this right here, which has two of them, is called ethoxide so what happens is this becomes a parent and this becomes the substituent so i would name this right here methoxide indicate what carbon is attached to so carbon one and then we name the parent one two three four five so pentane So let's go one, one methoxide pincine. So methoxide. just means this so why are ethers so special for us is because chemically ethers are moderately inert so do not normally react we're reducing agents or bases they're extremely volatile that which means they're highly flammable and easily oxidized in air the symmetrical ethers can be prepared by dehydrating to alcohol molecules this is another one that would add to your index cards And it requires heat and an acid catalyst. So the reaction is you're going to take one alcohol plus a second alcohol.
You're going to use some acid and some heat. So you need two alcohols. It could be the same alcohol twice.
It could be two different alcohols. And then what you get is you get ROR. And then you get your ether.
So medically, ethers are also very important to us because they can be used as anesthetics. And what they do is accumulate in the lipid material of the nerve cells, interfering with nerve impulse transmissions. And today, halogenated ethers are used routinely as general anesthetics because they're less vulnerable and safer to store and work with.
Our last group for this chapter, they're called thiols. And thiols have the formula of RSH. And thiols and alcohols are kind of similar in the way they kind of look. The difference is this. Instead of an O, we use an S.
So thiols are a base of sulfur. Similar in structure to alcohols with the sulfur replacing the oxygen. The name is based on the longest alkane chain with the suffix thiol position indicated by a number. So for example, carbon 1, carbon 2. So this is ethane thiol.
Now I don't have to indicate it because ethane, if I put it here, then that will become carbon 1. 1, 2, 3, 4. Next one. So it will be... 3-methyl-1-butane-thiol. Or you can do 3-methyl-butane-1-thiol.
Alright, and the next one. This one's going to be 1, 2, 3. five and you want to give those substituents the lowest possible number so this is going to be one comma four pentane and then we have two thiol so I have to indicate di thiol you can also do it as pentane one four di thiol So why are thiols so important to us? It's because thiols, as many other sulfur-containing compounds, can have nauseating aromas. For example, the smell of the skunks is a thiol smell, so it's caused by thiols. The smell of onions and garlics are also because of thiol compounds.
And then this one compares very much with alcohols. Alcohols tend to have a more pleasant smell to them than thiols do. So sulfur... It's really easy to recognize because it's so rotten, kind of garlic, kind of skunky. And then you have alcohols that smell a little bit nicer.
And then from this, we can also have something called a disulfide formation. So thiol disulfide redux pair controls a critical factor in protein structure called a disulfide bridge. And disulfide bridge are very important to us. And what we get is we get two cysteine molecules, which are amino acids.
When we get into the biochem unit we'll talk heavily about amino acids, but you can get specifically two of them called cysteine. And they can undergo oxidation. And what happens in the oxidation, we're focusing on this tile and this tile right here, which forms this right here, which is called the sulfide bond.
And we'll talk about more amino acids when we get into the biochem unit. If you have any questions, please let me know.