Not reversible? Fischer esterification is reversible. But your ethanol and sulfuric acid being very low in water, and the heavy excess of ethanol would heavily push the equilibrium in one direction. So I guess effectively not reversible, but using low concentrations of ethanol or sulfuric acid like a home chemist might do would lead to a bad equilibrium.
Yeah I hate that I made that comment when all esterifications are by definition reversible.. I really need to write scripts instead of just rambling out a monologue lol. In any case yeah some Fischer esterifications are VERY reversible where you would have a hard time getting much product at all without constant removal of water from the system, but others (like this one) can be overwhelmingly pushed to favor products by using a large excess of reagents. As a side note, I've noticed the ones that tend to favor the reverse reaction are esterifications where the reagent is a solid but the product is a liquid (like methyl salicylate). Ones where the products and reagents are the same state seem to favor both directions equally, and can be more easily pushed to favor products by using excess reagents. Definitely related to entropy but I hated thermodynamics so I can't say for sure lol
@integralchemistry1849 I would think Le Chatelier's principle would be coming into play if things are leaving solution. That should keep dragging the equilibrium in that direction. Monologs are part of why I've never been consistent with making videos. I talk too much. Overthink the whole thing and then never follow through. But the more I watch Chem videos, the more I realize some people like that stuff. There's obviously a limit somewhere. Can't drone on. But some people really just want a long video they can listen to so they don't have to hunt for another one so soon. More and more people are using RUclips as more of a background entertainment than their full focus. I'm so at a point where I don't really have a good place to do these reactions. Dogs are too nosy at home, and I don't want that kind of risk. But I have so many damn chemicals boxed up that I want to break out
I made the n-propyl analogue a few years ago (risocaine, or propyl 4-aminobenzoate). Interestingly, during the overnight crystallization of the crude reaction mixture, I smelled a faint but very distinct smell of artificial grape. Any ideas? The only thing that came to mind is methyl anthranilate. I've never smelled that compound, but I've heard it described as smelling like artificial grape. And both risocaine and methyl anthranilate are alkyl esters of an aminobenzoate; only the orientation of the amino group relative to the carbonyl are different. I have no idea if there's any connection at all, I can only report what I personally observed.
I'm thinking you likely just make the alkyl ester you're talking about^^ so many of those esters smell distinctly fruity (and that one is a distinct "grape" smell). What did you recrystallize in?
@@integral_chemistry It was the initial crystallization of the crude product from the neutralized reaction mixture. I did a few attempts at recrystallization and I had a problem with oiling out in ethanol, since the melting point of the crude risocaine was 71-72°C. Nothing worked really well and I gave up after a few tries and finding that the melting point did not improve with recrystallization. I didn't smell that grape smell again, so I don't know. I thought I might be imagining the smell originally but another person confirmed it when I asked them to check, so it wasn't just me.
I would't take anything into my mouth that's gone through the same devices as chromates, mercury-, cadmium- and nickel-compounds before... But if you do, it's better to dilute the benzocain with the typical pharmaceutical additives beforehand, because overdoses of benzocain can cause some very unpleasent side-effects like allergic reactions and severe gastrointestinal problems. Therefore here in Europe the use of lidocain is more common. If you still got some PABA, can you perhaps show the synthesis of anilline by decarboxylation (should be done under the fumehood) in another video?
The first thing that comes to my mind is mononitrating toluene and separating the 1,4 isomer, then oxidizing methyl group to -COOH and reducing nitro group to an amine one but I bet there are some easier and shorter methods
Pretty sure I made this in labs at uni 🤔 super cool! How did people figure out the reaction mechanisms 🤯
Not reversible? Fischer esterification is reversible. But your ethanol and sulfuric acid being very low in water, and the heavy excess of ethanol would heavily push the equilibrium in one direction. So I guess effectively not reversible, but using low concentrations of ethanol or sulfuric acid like a home chemist might do would lead to a bad equilibrium.
Keep up the good stuff! Loving your channel
Yeah I hate that I made that comment when all esterifications are by definition reversible.. I really need to write scripts instead of just rambling out a monologue lol. In any case yeah some Fischer esterifications are VERY reversible where you would have a hard time getting much product at all without constant removal of water from the system, but others (like this one) can be overwhelmingly pushed to favor products by using a large excess of reagents.
As a side note, I've noticed the ones that tend to favor the reverse reaction are esterifications where the reagent is a solid but the product is a liquid (like methyl salicylate). Ones where the products and reagents are the same state seem to favor both directions equally, and can be more easily pushed to favor products by using excess reagents. Definitely related to entropy but I hated thermodynamics so I can't say for sure lol
@integralchemistry1849 I would think Le Chatelier's principle would be coming into play if things are leaving solution. That should keep dragging the equilibrium in that direction.
Monologs are part of why I've never been consistent with making videos. I talk too much. Overthink the whole thing and then never follow through. But the more I watch Chem videos, the more I realize some people like that stuff. There's obviously a limit somewhere. Can't drone on. But some people really just want a long video they can listen to so they don't have to hunt for another one so soon. More and more people are using RUclips as more of a background entertainment than their full focus.
I'm so at a point where I don't really have a good place to do these reactions. Dogs are too nosy at home, and I don't want that kind of risk. But I have so many damn chemicals boxed up that I want to break out
You can make aniline from PABA too, just a decarboxylation.
DEA:🤓
I made the n-propyl analogue a few years ago (risocaine, or propyl 4-aminobenzoate). Interestingly, during the overnight crystallization of the crude reaction mixture, I smelled a faint but very distinct smell of artificial grape. Any ideas? The only thing that came to mind is methyl anthranilate. I've never smelled that compound, but I've heard it described as smelling like artificial grape. And both risocaine and methyl anthranilate are alkyl esters of an aminobenzoate; only the orientation of the amino group relative to the carbonyl are different. I have no idea if there's any connection at all, I can only report what I personally observed.
I'm thinking you likely just make the alkyl ester you're talking about^^ so many of those esters smell distinctly fruity (and that one is a distinct "grape" smell). What did you recrystallize in?
@@integral_chemistry It was the initial crystallization of the crude product from the neutralized reaction mixture. I did a few attempts at recrystallization and I had a problem with oiling out in ethanol, since the melting point of the crude risocaine was 71-72°C. Nothing worked really well and I gave up after a few tries and finding that the melting point did not improve with recrystallization. I didn't smell that grape smell again, so I don't know. I thought I might be imagining the smell originally but another person confirmed it when I asked them to check, so it wasn't just me.
Nice one mate 👍.
I would't take anything into my mouth that's gone through the same devices as chromates, mercury-, cadmium- and nickel-compounds before...
But if you do, it's better to dilute the benzocain with the typical pharmaceutical additives beforehand, because overdoses of benzocain can cause some very unpleasent side-effects like allergic reactions and severe gastrointestinal problems. Therefore here in Europe the use of lidocain is more common.
If you still got some PABA, can you perhaps show the synthesis of anilline by decarboxylation (should be done under the fumehood) in another video?
I would, have a nice day
@@Y0GAAAAWait a minute...
you allready do if you just buy medication or industry food so :)
Poderia mudar o sulfúrico por ZN ou então ácido fosfórico ? Daria certo?
How to made Benzocaine IP and Benzocaine BP
How can we make the PABA in our home lab? That would be an interesting topic.
The first thing that comes to my mind is mononitrating toluene and separating the 1,4 isomer, then oxidizing methyl group to -COOH and reducing nitro group to an amine one but I bet there are some easier and shorter methods
And the second process could be monomethylating aniline with methyl chloride, separating the 1,4 isomer and oxidizing methyl group to -COOH
3:34 Not "ok" actually - more like "noice" :-)
LMAO I thought the same thing
0:57 clear as mud, do you perhaps need a turboencabulator to make this work? Or perhaps it knows where it isn't?