Making Benzyl Chloride
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- Опубліковано 15 жов 2024
- I made some fast edits. Hopefully it's okay now.
In this video, we whip up some benzyl chloride. It is a pretty useful chemical and I plan to use it to make denatonium benzoate.
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Nile talks about lab safety: • Chemistry is dangerous.
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Another excellent video as usual. The SN1/SN2 explanation and mechanisms were much appreciated. I don't know about your other viewers, but I wouldn't mind seeing more technical information in the future.
I agree, this gave me a better understanding of the difference between the Sn reaction types.
chaemelion I agree. I’m a chemistry 1 high school student, so I don’t understand all of it, but it’s good info to have!
@@therainbowwillow4453 i am chemical engineering major currently...and i have leanrded a lot from nile ratjer from my proffessors
That explanation was amazing, I agree.
For all the people saying that this reaction will be overwhelmingly SN1 in terms of mechanism due to resonance stabilization, you would be right EXCEPT:
Expect experimentally, the sn1 and sn2 mechanisms for specifically benzyl halides are almost 50/50 favored. The reason for this is due to kinetics. Although the carbocation has exceptional stability and would be expected to be the major product, it relies on the relatively slow step of the water spontaneously leaving. The SN2 reaction proceeds via an attack by the relatively weak chloride nucleophile but this process can happen much faster. Therefore the reaction mechanism is almost an even split. Sn1 is greater favored due to stability but hindered by a slow leaving step. The sn2 is fast with the attack by the chloride, but does not have the benefit of the stability of resonance.
This illustrates the importance of kinetics for determining the experimental outcome of a reaction beyond theoretical expectations
As someone who works in an organic laboratory, it is very intriguing for me to see your videos! I say that because there are reactions that I simply never conducted in my career but have been taught in textbooks. It is very educating for me. Keep up the excellent content!
The benzylic carbocation is very stable and can be expected to contribute overwhelmingly to the reaction mechanism.
Exactly right. The reaction conditions (polar protic solvent) in combination with the benzylic position bascially are screaming SN1.
Expect experimentally, the sn1 and sn2 mechanisms are almost 50/50 favored. The reason for this is due to kinetics. Although the carbocation has exceptional stability and would be expected to be the major product, it relies on the relatively slow step of the water spontaneously leaving. The SN2 reaction proceeds via an attack by the chloride which can happen much faster. Therefore the reaction mechanism is almost an even split. Sn1 is greater favored due to stability but hindered by a slow leaving step. The sn2 is fast with the attack by the chloride, but does not have the benefit of the stability of resonance.
This illustrates the importance of kinetics for determining the experimental outcome of a reaction beyond theoretical expectations
Sn2 gets a stabilized transition state, don't forget that...
I believe this will be almost all Sn1. Chloride is a weak nucleophile, benzyl carbocation is almost as stable as a tertiary if not more, water is a great leaving group.
He called a benzylic carbon a primary carbon, I cringed. Totally agree with you.
Nabeel Chhatriwala Ha I subconsciously cringed as well! When I saw the positive charge on the aryl carbon group my mind was immediately imagining all the resonance structures available to stabilize the positive charge. Unfortunately I never got to the point of realizing the error in his rationalization of the predominant reaction mechanism occurring, but at least the right thought process was happening lol! oh well
It IS a primary carbon tho
Chris The Raven uhhhh, no. It’s a benzylic carbon. I suppose you could call it “secondary” but it’s quite different from aliphatic secondaries.
@@MisterLepton it's a carbon bound to another carbon. So, yes, it is primary.
This is much more Sn1 than Sn2 because the positive charge is extremely stable, having 4 resonance structures total
You would think so, but the ratios of which mechanism prevails is actually pretty close to 50/50. It all comes down to kinetics. Although the resonance stabilized carbocation is definitely very stable, the rate determining step is how quickly the H2O group spontaneously leaves. For SN2 reactions all it takes is the chloride coming in and attacking which happens much faster than the H2O leaving. So it’s almost a 50/50 mix. This illustrates the interplay between how kinetics, and resonance/sterics comes into play. From ones understanding of resonance, sn1 should be greatly favored and be the major product, but it’s fighting against the relatively slow process of the water molecule leaving. Whereas the sn2 attack by the chloride happens much faster before the resonance structure can be established.
@@spiderdude2099 correct me if my intuition is off here, but..
From what I understand, SN1 shouldn’t really happen here, since it‘s a terminal carbon atom, and even if you have a nice protic solvent the terminal carbocation should be waaaay too unstable. I don’t know to what degree the resonance structures would help, but in general terminal groups should always undergo SN2 reactions.
Edit: just looked it up. Substitutions in the benzyl position will prefer SN1 if the benzyl group has electron-donating groups attached.
As it is, the unsubstituted benzyl like seen here should prefer SN2.
@@moropikkuu the issue with that is that the stabilization given by resonance even by an unsubstitued benzyl ring is absolutely HUGE. Draw the resonance structures for the primary carbocation and you’ll see this. The charge is able to move to other carbons such that it leads to several resonance structures where the charge is on a secondary carbon. This greatly stabilizes it, and leads to SN1 occurring to a much greater degree than it should for being a primary carbon. The experimental results of performing SN1 vs SN2 reactions on benzyl halides comes out to around 50/50 because this effect is so strong. The effect of resonance can’t be overstated because, yes, you’re right as a primary carbon this should be much more dominated by SN2, but it’s not, they’re almost equal. It also has to do with kinetics. The resonance stabilized carbocation should actually make this reaction more SN1 than SN2, but the formation of the cation relies on the very slow kinetic step of water leaving and creating a charged carbon. Whereas SN2 doesn’t have this problem. It relies on nucleophilic attack which is a much faster kinetic step. This further leads to an equal split of the two mechanisms
Jesus, Bob.
I'm a big fan of you going over the reaction mechanism. My work mostly revolves around surface chemistry and watching vids like this keep the parts of my brain that learned organic chemistry alive.
I love in depth chemistry. More of that if you have time for it. :)
More theory definitely!
So this is the tear gas he made while trying to make Cherry Soda.
I left my chemistry cursus for about 10 years now (wow how times fly) and I completely forgot about Sn1 and Sn2. That brings back some old memories. Funny thing is that I always struggled with organic chemistry, but it seems all so logical now, even if I never used it in my working years.
Damn, you didn't mess around with this one lol. Your passion for chemistry really shines through with your thoroughness - really separates the amateurs from the real chemists! I was getting exhausted just from watching all the product purification steps you took lol. Good work!
I love all the mechanistic stuff. I'd love to see more in the future
I know this is an old video but I really appreciated the explanation of SN1 and SN2 mechanism.
I'm a chemistry student and before I was introduced to organic chem I was wondering what was happening in the reaction.
Your videos are great, I suggest you to put more explanations but also a time skip for those who are here for the calming and quality video.
Sn1/sn2 explanation was very informative and helpful. I appreciated it greatly as I only did an A level in chemistry and don't have a degree. I would have loved to have seen even more on the topic you mentioned of 'resonance'
Three uploads within 4 hours? What a day!
+GhostyOcean I've been workin hard :)
The detailed tangent was interesting, thanks for doing that!
Man I'm not a chemist or studying chemistry, but this channel is so interesting
Me too
@@lifeonfire2390 me three
For the record, I'm REALLY grooving on the extra explanation. It helps answer a lot of questions I've had (f'rinstance: If you mix KCl and NaOH, are you going to get NaCl and KOH? When doesn't this happen?
etc.
Between y'all and chemplayer, I'm actually lerning this stuff....
That's actually a good question. Basically, assuming by mix you mean dissolve both in water, the ions dissociate completely because the Ksp is high enough for KCl, KOH, NaCl, and NaOH. (If you haven't learned about equilibrium constants such as Ksp it might be good to look it up now.) So you just end up with a soup of K+, Na+, Cl-, and OH-. Usually when you have a reaction in the form of AB + CD > AD + CB it means one of the products is insoluble so it drops out of solution as a precipitate. For more information on that, look up double displacement reactions.
Alex I Dissolving in water was what I was initially picturing, yes, but only as a speculative starting point. I've heard of equilibrium constants, but I haven't delved into it all that deeply, and I think that might be a gap I'd wish to fill. Thanks!
That's some great yield for a fractional atmospheric distillation. I personally prefer to dry the final product with anhydrous potassium carbonate. It will both dry it and help remove any HCl dissolved during the distillation (I could see yours fuming as you poured it).
Excellent. I'm going to give it a try. I need benzyl chloride do go further on my synthetic route. Thank you for all explanation.
no problem!
how did making meth go
Your tangents are what answer alot of random question's I would either have to dig threw a book or annoy my collage professor to answer. Keep it up !
I would love to see more "theoretical chemistry" in your videos (which I already find very interesting)
It seems so easy when you make the reactions on a notebook, but on practice it´s an entire different thing, just like your video.
I'm currently studying Chemistry in my first year at university and I was wondering when you were talking about the mechanism of reaction here whether SN1 would be more prevalent due to the solvent being water. My thinking is that water is obviously protic and so can solvate the carbocation intermediate formed in by SN1 better than the transition state from SN2. Would you agree with this? I just want to make sure I have my understandings of how the mechanisms are affected correct. Also great job on the videos, really enjoy it when you synthesise multiple compounds and then use them to achieve the formation of a final product. I'm hoping to become a synthetic organic chemist so it's really interesting to me :)
6:53 how you can remeber that is by thinking like you'd calculate the average of the (idk the english word) regardless of negative or positive partial-charges.
So one negativ and one positive would be one, not zero, (1+1)/2.
You can see how having more carbon with the oxidation-number of 0 will equal out the one positive charge, this is also helpful for carboxyl-groups and the importance of the alkaline-tail regarding the hydrophobic/lipophile tendencies, which correlate directly to the number of CH(/H2/H3).
I really am enjoying the explanations and in depth discussions you are providing in these videos! Thank you. :)
After reading the comments and watching the video, I feel about as smart as a sponge.
Nice explanation of the SN1 and SN2 reactions. I noticed that the quality of the equations is often lower than the resolution of the video. Do you use Chemdraw? In this case I might have a hint :)
+Random Experiments International I do use it. What is your tip? :)
+Nile Red First you draw everything as usual. Then you increase the size of the document. (File -> Document settings -> Layout -> Poster) I usually change it to 100 cm x 100 cm. Then I mark everything and make it as large as possible. I know it sounds a bit stupid, but when you save this document as a picture, the resolution is much higher :)
Cool, i never even thought of increasing the document size.
Very nice, Nile. Both your lab technique and your explanation of SN rxns were lovely. I only worried about the lack of a fume hood.
Sn2 is just the H an CL attaching simultaneously. It doesn't need to go around anything. H and CL while dissociated travel together.
great information on the Sn1 and Sn2 reactions. thank you
Hey, Nile!
Good on you for getting so many videos out in such little time. Cool information!
Question: Would you say this Benzyl Chloride here burned your eyes as much or less than the chloroacetone?
Never encountered chloroacetone, but benzyl chloride is not as bad as chloropicrin, which feels like hot sauce in your eyes.
+TheBackyardScientist Damn!
Yeah the benzyl chloride was a bit less painful than
getting soap in my eyes for a few hours.
+Nile Red ouch.
+Nile Red I stored like 75ml of this in a Pyrex reagent bottle, and opened it after a few days and as soon as I opened the cap it sprayed a mist out and freaked me out. I liked for the decomposition facts on it but couldn't find much. and it turned a muddy brownish red color. it was over molecular sieves also. any ideas on why? did it decompose? it was out of light but in a hot garage seeing how I really don't want it in my house. how long is the shelf life? I've tried finding lit on it but come up empty handed.
I've just learned and remembered something else for my tomorrow's mechanism reaction exam!
I love you 💖
Stabilization, with Soul resonance.
Benzyl Chloride is also used as a disinfectant.
The waste HCl acid with residual benzyl chloride from the first seperation waste should be digested with NaOH too before being thrown down the drain. Then preferably neutralized with more HCl that way only saltly water is being chucked down the drain.
I learn more from watching this 16 minute video than sitting in my 2 hour O Chem lecture
You, chemplayer, and nurdrage all uploading several videos all within hours of each other. It's been pretty entertaining.
I believe the SN1 pathway to be correct in this case due to the weak nucleophilicity of the chloride ion paired with toluene's ability to easily stabilize carbocations, carbanions, and even radicals through resonance.
Molecular Siths O_O. At last, the dark side has water-free benzyl chloride....
Yes lol it's interesting how he pronounces it. We Americans say "seevs"
I don't understand how significant it is that the Sn1 process takes place. The Sn2 should be pretty much instantaneous, but if it's competing with the Sn1 mechanism to a small extent, wouldn't the act of creating that benzylic carbocation slow down the reaction time?
I'm just now realizing what the sn1 and sn2 substitution after being in IB chemistry HL and you explained it really good
Everyone: talking about the reactions and what not
Me: Cahe here to see small water tornados, and becauss the procedure looks fun
Lol I paused at 8:18 when you said to get back to the reaction at hand, and left a comment about resonance, then you covered it so I had to delete the comment xD love your videos, keep up the great work.
It would be pretty neat if you could do some teaching videos like Kahn academy to go over organic mechanisms like you did here describing Sn1 and Sn2
I'd like to see you doing a scratch synthesis of strychnine, It would be a long haul!
Ha ha wonder what ur really trying to synth
I would like to see the benzoic acid and benzaldehyde videos next. And I think the methyl iodide and methylamine hcl videos would be nice to see in the future.
It would also favor some Sn1 because the reaction is performed in a polar protic solvent (water).
I did enjoy the organic chemistry lecture; reminded me a little of OChem 2 with Dr. EJ McWhorter!
this is pretty informative pls do more when you have time. thank you
Its not just resonance! it is hyperconjugation of the sp2 carbon atoms with a movile charge! So yes, its fucking awesome chemistry.
wow what a chemistry day great job nile love your vids.
Lovely and beautiful synthesis :)
Benzyl chloride is useful to synthesis Benzyl Cyanide a useful reagent. But its manufacture is quite hazardous.
Great preparation man.
The reaction conditions (polar protic solvent) in combination with the benzylic position bascially are screaming SN1. SN2 plays a very minor role, if any at all.
Also, I think it would be fun to see some polymer chemistry on this channel.
Dude I have a test about this exact topic today, thanks for the explanations.
Great vid but i really wanna see someone do it with N-bromosuccinamide or N-chlorosuccinamide and toluene.
Have you ever tried this?
I did. Symclosen (swimming pool), toluene and some radical starter for the polymerisation of styrene. Heating and reaction started. Use symclosen in some batches and every time new radical starter.
I wonder if NileRed used a respirator and a fume hood with it. I read on wiki that this is a hell of a toxic compund. Wouldn't want to harm myself worse than I did from ammonia synthesis (took a whiff out of curiosity and felt some of the symptoms). Yet, who knows. Safrole isn't nearly as dangerous as it has been made out to look by the DEA, maybe same stuff could apply for BzCl.
Watching this reminded me of how much I forgot of my organic chemistry lessons :(
I knew your avatar looked familiar. Could it be fate...
Kronos DAW oh hai :D
Nilered got the cleanest drain pipes in the world after all the chemicals he has flushed down the drain
He sends off all the waste products to a chemical disposal company
Love the extra info.
i miss this kind of content 😢
Hey Nigel... this is a great video... I was just curious (as I am studying in high school organic chemistry) about why you didn't use the lucas reagent which makes hydroxyl a better leaving group and instead went for increased amount of hcl which is not as effective for increasing the rate of reaction. Your reasoning would help me understand the topic better, I would really appreciate your help as I am preparing for JEE.
Excellent... Preparation of Benzanalide and please how to handle benzyl chloride in laboratory it's safety measures how to discard it and all...
Thanks a lot for this video
NICE, THANKS FOR UPLOADING!
Woot in depth chemistry!
Hey I don't know exactly where to vote but I really like to see the acetone video. Hope voting here in the comments section counts too. By the way I love your videos they are awesome :)
hello, im a chemist, good video. I think this helps students and amature chemist in understanding sn2 vs sn1. Maybe you can make a vid on solvent effects and sterochemistry of sn1 vs sn2. I should also mention that benzylchloride is on list II of DEA compounds.
So is everything else on the planet
9:22 It's not depth chemistry, it is Grade 12 1st lesson in NCERT.
Water is a polar protic solvent, which favours Sn1.
Like this video!!
That is true. I honestly kind of forgot to take solvent into account.
+MsMrVlog well the fact it is a primary alcohol which has an very stable carbocation by resonance in the phenyl proves a lot more the fact it is Sn1 than the polar protic solvent. Plus, in acid conditions, the protonation of alcohols yields a very good nucleofuge that favors Sn1 too.
+Michael Desgagne I know, but the solvent is just giving a small extra push which is worth mentioning
That is true
Where are you from? Since this substance is classified as List II precursor to drug manufacturing by US drug enforcement agency.
He is canadian
"I don't want to fill my garage w/ hydrochloric acid vapor for obvious reasons"
Another on the list of reasons I don't do this at home and just watch these videos :D
hey, you said "sieve" right in this one!
2 videos in one night ?!? Wow awesome !
I have no clue what you're saying, but I'm enjoying your content all the same
Benzyl Chloride for Benzyldehyde.
Hey brah, you forgot to mention that the Benzyl Chloride will be the TOP layer after the sat’d NaCl wash! Here I am wondering why my calcium chloride turned to a powder and precipitated out of solution as if it were soluble in the product and I thought “wait a second, this isn’t right, what’s the density of BnCl? 1.1 g/mL. What’s the density of sat’d NaCl? 1.2 g/mL. Well no shit......”
So yeah, good thing I didn’t dump it in the waste container.
Oh, and I also didn’t think you adequately emphasized the *EXTREMELY PERSISTENT* smell of this stuff. It will stick around for DAYS and will even somehow follow you around for short distances (apparently it gets trapped in your glasses, clothes, hair, etc). Probably because it has an odor threshold of 0.044 ppm!
Exactly what happend to me. The strange thing is, that the powdee disappeared when I put more Sodium carbonate solution.
Benzylic cation is very stable!
congrats you now got 32000 subs congrats
Boiling hydrochloric acid is my acid metal band's name.
Benzyl Chloride was a great actor in sherlock
A very nice yield
I have a midterm on sn1/sn2 stuff soon, youtube really is always watching
2:01 No stir bar visible? _What is this sorcery?!?_
just curious haha, anyways nice video, keep up the awesome content!
+Ben Sullivan That round bottom flask is tricky. From that angle, the stir bar disappears.
Do u think you can look into making picric acid from paracetamol as a future video?
pharoahs serephant (i have no idea how this stuff is written....i mean that mercury poison snake)
and do a video on cleaning llithium and more easy stuff (what you can do at home like extractions)
This video was brought to you by Walter White’s Blue Meth Production Team.
wouldn't it by a dehydration synthesis rather than hydrolysis cuz stuff is being put together rather than broken down, and you get water as an output not an input (plus your boiling water off to form substance, rather than adding water to break stuff up) sorry im starting college courses and I think we learned this but I dont know if its correct.
If you added something to bind the water during the original reaction, could you reduce the reverse rate (and therefore, possibly, increase the yield)?
+Raph Guenther In theory, but the amount of water present it crazy. You could generate HCl gas instead, but it is a lot of work for not that much gain
@@NileRed agreed.
Denatonium benzoate (Bitrex) is the product of a local anesthetic (Lidocaine) and benzyl chloride ? Strange.
If I were trying to produce an intensely bitter substance, I doubt that I would first consider using these two compounds.
Sounds as if someone was trying to produce something besides a bitter flavoring and stumbled across Bitrex.
The more interesting question for me is /how/ these two mechanisms can be tested for in the reaction. Without a way to measure it, this is at best theory and at worst speculation.
How is that done?
Why can't you do the experiments in fume cupboard which is ventilated? It's very unsafe to do that without PPE and hood
I'm happy to leave work so I can come to school hahaha
Where were you when I was in O-Chem?
Totally not gonna use this at my neighbors
would it be inadvisable to use a higher concentration HCL to achieve an excess of HCL with less liquid volume, or would the exothermicity of the reaction actually cause issues with the chemistry being favored toward an undesirable combination.
Alternative title: how to make tear gas!
tells me its extremely bitter, tells me if i taste it my tongue will melt off