Organicsynth
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Problem using Chloroacetyl Chloride
I'm trying to make a reaction with chloroacetyl chloride.
I put the chloroacetyl chloride inside a dropping funnel with a pressure equalization tube, then I close the funnel with a glass lid to avoid moisture
from the air to make contact with it.
Then, I add it dropwise for 10 minutes to my round bottom flask that's being stirred.
The problem is that when the drops of chloroacetyl chloride start hitting my reagent on the flask, it creates HCl, the pressure builds up and it pops
my lid.
I let the gas get out and then close the lid again.
But now I think to myself: "If HCl gas was created inside the flask, it means now that instead of chloroacetyl chloride, I have HCl acid inside the
reaction, thus, making it impossible to react properly".
I'm being paranoid? Or should I really try to use another method to avoid the formation of HCl gas and acid? I don't know what I can do to achieve a
very dry working environment inside the flask.
I also have a weird question, what would happen if I added 500ml of water to 500ml of chloroacetyl chloride immediately? Would it explode? Would it be
extremely dangerous?
Not looking to do it of course but I like to know this for safety reasons.
Even drop by drop I see alot of HCl being formed so I can't help to wonder what would happen if by a mistake adjusting the dropping funnel alot of
chloroacetyl chloride went into the flask in one go.
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mackolol
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Quote: Originally posted by Organicsynth  |
But now I think to myself: "If HCl gas was created inside the flask, it means now that instead of chloroacetyl chloride, I have HCl acid inside the
reaction, thus, making it impossible to react properly".
I'm being paranoid? Or should I really try to use another method to avoid the formation of HCl gas and acid? I don't know what I can do to achieve a
very dry working environment inside the flask.
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I don't know what are you reacting your chloroacetyl chloride with, but HCl is a byproduct. The chlorine atom is just reacting with hydrogen at the
end of the second organic compound and it just goes away as HCl gas, not acid as acid is HCl dissolved in water and as you have said there is no water
in the flask. You should know it before working with such expensive and dangerous compound.
| Quote: Originally posted by Organicsynth |
I also have a weird question, what would happen if I added 500ml of water to 500ml of chloroacetyl chloride immediately? Would it explode? Would it be
extremely dangerous?
Not looking to do it of course but I like to know this for safety reasons.
Even drop by drop I see alot of HCl being formed so I can't help to wonder what would happen if by a mistake adjusting the dropping funnel alot of
chloroacetyl chloride went into the flask in one go. |
The HCl just goes from reaction, which is probably violent, because that's how acyl chlorides react with organic compounds. But when you add it to
water, you would be surprised how slow the reaction goes in room temp, this is yet another reason that you're not dealing with hydrolysis.
Answer to your question is here, I bet that PCl3 is similar enough to CAC in matter of water hydrolysis:
https://www.youtube.com/watch?v=mYDYtsJ4NbQ time: 9:20
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Organicsynth
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| Quote: Originally posted by mackolol |
I don't know what are you reacting your chloroacetyl chloride with, but HCl is a byproduct. The chlorine atom is just reacting with hydrogen at the
end of the second organic compound and it just goes away as HCl gas, not acid as acid is HCl dissolved in water and as you have said there is no water
in the flask. You should know it before working with such expensive and dangerous compound. |
That makes sense, I thought that was the cause I didn't get the correct final product but it wasn't.
The air is moist, around 50% RH but inside a 500ml flask? That probably only produces traces of HCl acid.
And besides, HCl gas is heavier than air, so even if I had the dropping funnel lid open, it shouldn't be a problem, right?
I need to use TLC to check the 2 reactions that happen on my synth. I probably started reaction 2 too early.
I'm still waiting for n-Heptane to be able able to do TLC to check if the reactions are complete.
I'm too impatient :<
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dawt
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You should be using a drying tube if you want gasses to get out without letting water vapour in. You can also likely replace the heptane with petrol
ether, cyclohexane etc.
I concur with mackolol - take this stuff into account and plan everything out before starting your reaction.
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mackolol
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| Quote: Originally posted by Organicsynth |
I need to use TLC to check the 2 reactions that happen on my synth. I probably started reaction 2 too early.
I'm still waiting for n-Heptane to be able able to do TLC to check if the reactions are complete.
I'm too impatient :< |
Maybe just share, what exact reaction are you trying to perform. What product do you want to make. TLC won't help you if you're doing things wrong and
even if you're doing it right, I don't know if TLC is necessary to check it...
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Organicsynth
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I wish it was easier to find more information on how to work with certain reagents.
The problem is that alot of times there's almost nothing about it, so I need to try and keep trying until I find a suitable solution.
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Chemi Pharma
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@Organicsynth, I'm attaching the paper I've said to you by U2U.
Good luck
Attachment: Synthesis of 5-Phenyl-1,4-benzodiazepine-2-one.pdf (120kB)
This file has been downloaded 431 times
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Pumukli
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" the pressure builds up and it pops my lid"
I think you have a problem in your setup!
Maybe you are trying to carry out this reacttion in a closed vessel!
Dawt pointed out: you should use a drying tube in your system in this particular case, (and probably a plastic tube at the end of it would not hurt,
just to be able to went the HCl gas safely away).
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pip
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I’m interested in how you acquired chloroacetyl chloride than your diazepam synthesis.
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FrenchChemist
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Buying such simple and cheap acid chlorides is always better than synthesizing and wasting valuable chlorinating substances.
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pip
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It’s not an acid chloride, the acid chloride would be acetyl chloride which is as hard to buy as acetic anhydride. Sure it can be made, but
chloro-acetyl-chloride is even less available to amateurs. It’s synthesis is even more problematic.
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FrenchChemist
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| Quote: Originally posted by pip | | It’s not an acid chloride, the acid chloride would be acetyl chloride which is as hard to buy as acetic anhydride. Sure it can be made, but
chloro-acetyl-chloride is even less available to amateurs. It’s synthesis is even more problematic. |
Yes, of course, I simplified it too much. In Acros is in the acid halides category, hence my generalization.
Simple synthesis from chloroacetic acid and thionyl chloride. But as I mentioned it is a pity to waste valuable chlorinating reagents and it is better
to buy. All acid chlorides are rather hard available to amateurs, but if you know where to look ......
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pip
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I think you’re in the wrong place, this is an amateur forum. Things like ordering from Acros and having Thionyl chloride on hand are professional
chemist luxuries.
I’ve actually been researching synthesis of these two chemicals. Chloracetyl chloride from acetic anhydride is doable, even then that requires a
ketene lamp for most of us. Thionyl chloride production is on the level of elemental phosphorus. And unlike phosphorus it’s not easy to buy. Buying
10kg of phosphorus is easier than 100ml of thionyl chloride.
[Edited on 31-1-2021 by pip]
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pip
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Patent for chloroacetyl chloride from acetic anhydride with lithium chloride to prevent polychlorination
https://patents.google.com/patent/US3576860A/en
I’m still at a loss to get a thionyl chloride synthesis that we can even pretend is safe on an amateur level in around a 500ml quantity.
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FrenchChemist
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If you can't get it, don't put everyone in one bag that they can't either.
Thionyl chloride is not as bad as it is described, the fumehood it's an absolute minimum if you value health.
Same as I read about lacrymatory power of benzyl chloride.
And what ??
Absolutely not. It has a strange benzene-toluene smell, nothing irritating.
You still need acetic anhydride in the patent you sent.
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pip
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Acetic anhydride is easy on an amateur level using a ketene lamp, it’s not quick but it is easy. Thionyl chloride is a chemical weapons precursor,
they’re not on the same level.
But by all means if you know of a thionyl chloride synthesis please share because burning sulfur and leading the so2 into pcl5 is the closest I’ve
found to otc. I’m lucky to have the phosphorus to do it, but I can’t expect others to have the luxury of using elemental phosphorus to do it.
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FrenchChemist
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Pip
Do you have white phosphorus or red?
From white there is a straight path to PCl3.
You have PCl3, you don't have to worry about thionyl chloride (in general, of course, not in every synthesis)
There is no simple synthesis to thionyl chloride.
And distilling it is not the most pleasant.
Maybe in this case it's worth trying with PCl3 ??
And if red - PCl5 ??
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pip
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Red, but you supposedly can get pcl3 from pcl5 by heating and driving the chlorine off.
My goal is 1-dimethylamino-2-propanol to the chloropropane
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FrenchChemist
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Red ----> so PCl5
don't need PCl3
you can easily convert Your alcohol to chloride via PCl5
use chloroform and that's all
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njl
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Sorry @FrenchChemist, are you saying benzyl chloride is not irritating?
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FrenchChemist
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totally not for me. It has a strange mega benzene-toluene smell and leaves a strange aftertaste in the mouth. Does not cause tearing or irritation
(only when poured directly on the skin - but who does?), nothing is happening to the mucous membranes.
I don't know, maybe you're very sensitive.
After working with diethyl ether, I never had dizziness (all-day work - not very ventilated room)
People like to demonize things, then I open the original packaging and nothing.
Of course, thionyl is nasty and chlorides like: propionyl, acetyl, chloroacetyl - are irritating. But benzyl, surprisingly, doesn't work for me at
all.
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njl
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I totally agree most things are blown out of proportion for amateurs, but the effects of BzCl is not something I would have imagined varies much
between people.
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Chemi Pharma
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@pip, try the synthesis described at the Patent I'm attaching below that uses trichoroetilene, chloroacetic acid and p-toluene sulfonic acid to make
chloroacetyl chloride with good yield in a easy way. The raw materials are non watched and relatively easy to find and buy on the market.
Better than use dangerous thionyl chloride or nasty PCl3/PCl5 or watched acetic anhydride.
Take a look at the Patent.
Attachment: chloroacetyl chloride from trichloethylene, chloroacetic acid and p-tolueno sulfonic acid.pdf (361kB)
This file has been downloaded 340 times
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pip
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Thanks, I appreciate it
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