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Author: Subject: erythritol tetranitrate recrystallization
foreign maple
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[*] posted on 23-8-2020 at 09:18


yes MeOH will work for recrystallization but you need to heat it to desolve the ETN.
I believe that 115ml of MeOH will desolve 10g of ETN at room temp.
i would reccomend heating up your MeOH to 35-45C and crash your ETN solution into a water bath that is 5c.:)

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aromaticfanatic
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[*] posted on 23-8-2020 at 21:18


Yup the heating is a good idea. Just use a hot water bath and don't use a hot plate near it. Not worth risking the detonation if it catches fire. There is a thread on this exact thing happening. Don't be the person to make another post on that thread.
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[*] posted on 24-8-2020 at 16:08


You are right. Please use a hot water bath or something to heat your MeOH not direct heat of flame that is just asking for a bad day.
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Herr Haber
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[*] posted on 25-8-2020 at 13:35


Quote: Originally posted by aromaticfanatic  

Also a nice tip I discovered which may be a little risky is to dump your ETN in the acid mix into a smaller amount of water all at once with no stirring initially. It favors larger crystal size which filters wayyyy faster and makes it less likely for the filter paper to be eaten apart due to being in contact with acids for a long time.


Dumping the nitration mixture in too little water seems a perfect way to lose product by local overheating.
It does not promote larger crystal size as they are already formed when you drown it.
Water will dilute the acid to the extent it wont be a problem for paper if you use enough of it !




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aromaticfanatic
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[*] posted on 25-8-2020 at 15:28


Quote: Originally posted by Herr Haber  
Quote: Originally posted by aromaticfanatic  

Also a nice tip I discovered which may be a little risky is to dump your ETN in the acid mix into a smaller amount of water all at once with no stirring initially. It favors larger crystal size which filters wayyyy faster and makes it less likely for the filter paper to be eaten apart due to being in contact with acids for a long time.


Dumping the nitration mixture in too little water seems a perfect way to lose product by local overheating.
It does not promote larger crystal size as they are already formed when you drown it.
Water will dilute the acid to the extent it wont be a problem for paper if you use enough of it !

? how would overheating be an issue? As long as nothing boils, you can just let it cool. With good stirring decomposition is negligible. In my experience I still got pretty good yields using this method.

The crystal size is formed during dumping and you can change the crystal size using different conditions. It changes crystals size or at least density. In my experience the crystal size was definitely changed. The crystals were much larger during the small water amount dumping. In the large water dumping I got very fine crystals.

Also you do use the water to make things less acidic but the main reason you dump the nitration mix in to water is to precipitate the ETN as it is much less soluble in water than in concentrated acids. Whenever I used the large crystal method, the initial dumping is just for crystal size. Afterwards I dump that water amount into larger amounts of water to dilute it for filtering.

[Edited on 25-8-2020 by aromaticfanatic]
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[*] posted on 25-8-2020 at 16:03


I have not tested it, but I always assumed you get a higher purity product by using more water in the initial drowning. If you use less water the acid is more concentrated. If the crystals are larger as you say, then surely they are holding onto more acid? In my opinion the less acid you are removing in your neutralisation/recrystallisation the better.
@aromaticfanatic do you need more than one recrystallisation for your ETN?
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[*] posted on 26-8-2020 at 04:40


Quote: Originally posted by aromaticfanatic  
Yup the heating is a good idea. Just use a hot water bath and don't use a hot plate near it. Not worth risking the detonation if it catches fire. There is a thread on this exact thing happening. Don't be the person to make another post on that thread.


In case people were wondering, here is the thread in question: https://sciencemadness.org/whisper/viewthread.php?tid=22554




As below, so above.
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aromaticfanatic
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[*] posted on 26-8-2020 at 09:15


Quote: Originally posted by B(a)P  
I have not tested it, but I always assumed you get a higher purity product by using more water in the initial drowning. If you use less water the acid is more concentrated. If the crystals are larger as you say, then surely they are holding onto more acid? In my opinion the less acid you are removing in your neutralisation/recrystallisation the better.
@aromaticfanatic do you need more than one recrystallisation for your ETN?


Yea it does hold on to more acid which is why it's a little riskier since it's more sensitive. I recrystallize once or twice using baking soda. You can't count the acid dumping as a proper recrystallization.

But yes you're right, the purity is less but filtering is quicker.
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[*] posted on 26-8-2020 at 09:49


I have to agree I have never heard of the crystals being formed upon addition to water, or that ETN was very soluble in acid baths. And as Herr Haber said, I have lost product by trying to use small amounts of water in a pipette to clean the sides of my reaction beaker. The water quickly shoots up to a temperature that will burn skin, not good for the ETN yields. Your acid purity may play a part as to why you do not have this issue. When I use drain cleaner I never get a temp spike like this, only with lab grade.

As far as the danger of leaving acid in your product, it has only ever made my ETN harder to initiation and weaker. It kills the shelf life to around 20 days, the ETN will literally just disappear as it is destroyed.
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[*] posted on 26-8-2020 at 10:35


Quote: Originally posted by aromaticfanatic  
Quote: Originally posted by aromaticfanatic  

Also a nice tip I discovered which may be a little risky is to dump your ETN in the acid mix into a smaller amount of water all at once with no stirring initially. It favors larger crystal size which filters wayyyy faster and makes it less likely for the filter paper to be eaten apart due to being in contact with acids for a long time.



? how would overheating be an issue? As long as nothing boils, you can just let it cool. With good stirring decomposition is negligible. In my experience I still got pretty good yields using this method.

The crystal size is formed during dumping and you can change the crystal size using different conditions. It changes crystals size or at least density. In my experience the crystal size was definitely changed. The crystals were much larger during the small water amount dumping. In the large water dumping I got very fine crystals.

Also you do use the water to make things less acidic but the main reason you dump the nitration mix in to water is to precipitate the ETN as it is much less soluble in water than in concentrated acids. Whenever I used the large crystal method, the initial dumping is just for crystal size. Afterwards I dump that water amount into larger amounts of water to dilute it for filtering.

[Edited on 25-8-2020 by aromaticfanatic]


So is it with or without stirring ?
Because without stirring you are losing product for sure.
I'm pretty sure these are crystals in the slurry prior to drowning.
But since you are going to recrystallize in the next few minutes, why would you care about their size and shape at that point ?

Just get your solvent and prefered base to neutralize the acids and get you the crystal size you're after, filter, dry, weight.




The spirit of adventure was upon me. Having nitric acid and copper, I had only to learn what the words 'act upon' meant. - Ira Remsen
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aromaticfanatic
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[*] posted on 26-8-2020 at 12:08


Quote: Originally posted by Herr Haber  
Quote: Originally posted by aromaticfanatic  
Quote: Originally posted by aromaticfanatic  

Also a nice tip I discovered which may be a little risky is to dump your ETN in the acid mix into a smaller amount of water all at once with no stirring initially. It favors larger crystal size which filters wayyyy faster and makes it less likely for the filter paper to be eaten apart due to being in contact with acids for a long time.



? how would overheating be an issue? As long as nothing boils, you can just let it cool. With good stirring decomposition is negligible. In my experience I still got pretty good yields using this method.

The crystal size is formed during dumping and you can change the crystal size using different conditions. It changes crystals size or at least density. In my experience the crystal size was definitely changed. The crystals were much larger during the small water amount dumping. In the large water dumping I got very fine crystals.

Also you do use the water to make things less acidic but the main reason you dump the nitration mix in to water is to precipitate the ETN as it is much less soluble in water than in concentrated acids. Whenever I used the large crystal method, the initial dumping is just for crystal size. Afterwards I dump that water amount into larger amounts of water to dilute it for filtering.

[Edited on 25-8-2020 by aromaticfanatic]


So is it with or without stirring ?
Because without stirring you are losing product for sure.
I'm pretty sure these are crystals in the slurry prior to drowning.
But since you are going to recrystallize in the next few minutes, why would you care about their size and shape at that point ?

Just get your solvent and prefered base to neutralize the acids and get you the crystal size you're after, filter, dry, weight.


No it's with stirring. And I thought the ETN is still soluble in the acids up to a point. I had ETN crystallize out once using KNO3 after the sulfate/metabisulfate salt kicked ETN out of solution all at once. It caused a large temperature spike. I've had no issues so far. I use cold water and stir the water right before addition and dump it. I've gotten 70% yields using NH4NO3 and drain cleaner. I was only able to reach a max of around 40% yield using lab grade 98% sulfuric acid (I also tried drain cleaner and there isn't much of a difference) and KNO3.

I use the larger crystal size for quicker filtering which I mentioned earlier. If I dump into a large amount of water, it forms very fine crystals which clog up the filter and take ages to filter. The larger crystals filter much quicker.
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[*] posted on 26-8-2020 at 14:40



No it's with stirring. And I thought the ETN is still soluble in the acids up to a point. I had ETN crystallize out once using KNO3 after the sulfate/metabisulfate salt kicked ETN out of solution all at once. It caused a large temperature spike. I've had no issues so far. I use cold water and stir the water right before addition and dump it. I've gotten 70% yields using NH4NO3 and drain cleaner. I was only able to reach a max of around 40% yield using lab grade 98% sulfuric acid (I also tried drain cleaner and there isn't much of a difference) and KNO3.

I use the larger crystal size for quicker filtering which I mentioned earlier. If I dump into a large amount of water, it forms very fine crystals which clog up the filter and take ages to filter. The larger crystals filter much quicker. [/rquote]

May I ask you method of synthesis and what kind of drain cleaner? My ETN using lab grade is light-years different in both color and performance.
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aromaticfanatic
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[*] posted on 26-8-2020 at 15:04


Quote: Originally posted by Brightthermite  

No it's with stirring. And I thought the ETN is still soluble in the acids up to a point. I had ETN crystallize out once using KNO3 after the sulfate/metabisulfate salt kicked ETN out of solution all at once. It caused a large temperature spike. I've had no issues so far. I use cold water and stir the water right before addition and dump it. I've gotten 70% yields using NH4NO3 and drain cleaner. I was only able to reach a max of around 40% yield using lab grade 98% sulfuric acid (I also tried drain cleaner and there isn't much of a difference) and KNO3.

I use the larger crystal size for quicker filtering which I mentioned earlier. If I dump into a large amount of water, it forms very fine crystals which clog up the filter and take ages to filter. The larger crystals filter much quicker. [/rquote]

May I ask you method of synthesis and what kind of drain cleaner? My ETN using lab grade is light-years different in both color and performance.


Yea sure thing. My ETN synthesis took me a few months to get right which just turned out to be KNO3's fault.

I use 15g erythrtiol, 60-70g NH4NO3, and 100-120mL of H2SO4.
I add the nitrate salt to the acid and keep temp below 30-40C. Then once completely dissolved, I chill the mixed acids down to around 3-5C. I begin slow additions with lots of stirring and keep the temp at 5-8C. Additions take around 30 minutes to an hour. Then I let it stir for 20 minutes at ice bath temps (0-8C). I raise the temp to 15C for around 30 minutes and then up to 20C for another 30 minutes. I crash it into around 250-400mL of ice cold water with lots of stirring. Then I dilute it further with around 1-2 liters of water. Filter, wash with water, wash with bicarb solution, wash with water and then I let it dry. I get around 23 grams that way once completely dry. For some reason I tend to lose a lot of product during recrystallization even though it's already reasonably pure ETN. I'd expect to lose 5 grams max but I sometimes lose up to half of my product. I never bothered to figure out why.

I recrystallize by adding the ETN into warm methanol (yellow HEET bottle methanol) and then I hot filter if there is some stuff that won't dissolve and then I dump into cold water with stirring.

Oh yea and the drain cleaner is this drain cleaner:

https://www.menards.com/main/grocery-home/housewares/cleanin...



It's 93% and gives good ETN. I save my good lab grade acid for more important and pickier synthesis but I'm sure I can get even better yields using the 98% acid since there is less water to push the equillibrium to the left.

[Edited on 26-8-2020 by aromaticfanatic]
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[*] posted on 30-9-2020 at 00:28


Regarding the recrystallization process, did I understood correct that the product is dissolved in minimum amount of rt solvent and then dumped in water to precipitate out fine crystals? Could the water be basified with amount of sodium carbonate to neutralize any residual acids?

The recrystallization in other circumstances is done with using steep solubility curve solvent by dissolving in minimum amount of boiling solvent and then cooling to precipitate. It appears to be not the case in this context. Shouldn't acetone do fine then, because it is as well miscible with water as alcohols?
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[*] posted on 30-9-2020 at 04:43


Yes, you understood correctly.
Browsing the forum you'll find people use sodium carbonate, bicarbonate, ammonia to neutralize the acids. I dont believe someone demonstrated one base is better than the others.
Some people suggested using the leftover water after filtering the crude product to dissolve your favorite base while at the same time dissolving the ETN in solvent.
Doing both cant hurt.

Recrystallizing in the solvent without dumping in water should only be done when all acids are removed to modify cristal size / form.
Acetone is fine despite a lot of people saying it isnt.




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[*] posted on 30-9-2020 at 13:26


I add my base of choice directly to the dissolved ETN/acetone solution for neutralization and have great results with this. Herr Haber, have you had any experience with acetone separating like in my perversely posted picture?
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[*] posted on 30-9-2020 at 22:05


Esterifications like this O-nitration of erythritol are equilibrium reactions, so adding water (one of the products of the reaction) to the mix will begin to decompose the product and reform the reactants. By keeping the temperature as low as possible during the dilution step of the process you can keep the rate of the reverse reaction very low and thus ensure that as little of the product as possible is lost. For this reason, nitric esters should never be kept in an aqueous environment with low pH for extended periods of time. If the pH is neutral, the reaction is not catalysed, so the rate is very low.
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[*] posted on 1-10-2020 at 03:15


Nope, nothing of that extent. I dont really remember as that was a long time ago but might have seen a blob remaining at the bottom trapping a little bit of NaHCO3.
I have very little to add to your guesses / theories. They're sound and I dont see how you could underestimate the volume of water still present by that much ( around 50ml in a total of 100ml right?).

In your shoes I would try the synth again without changing other parameters, filter, wash and dry the crude product before dissolving in acetone to see if there's any difference.
Also, I dont know how big your big beakers or containers are but I would not hesitate to use much more acetone than needed (more than what litterature tells) and crash it into much more water than needed again.
This should give you a very fluffly and light product very different from the table sugar most people aim for but it certainly has it's uses.




The spirit of adventure was upon me. Having nitric acid and copper, I had only to learn what the words 'act upon' meant. - Ira Remsen
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[*] posted on 2-10-2020 at 17:42


Thank you for the advice, I believe I will do just that. The batch of ETN I had the acetone trouble I kept an eye on. I suspected it was not neutralized, so I put a small sample in a clear sealed tube and came back a week or so later to the tube full of orange gas. This batch I did not crash into water, I added my base directly to the acetone and allowed it to evaporate to recover my product. Some times I am to actually hear the base and acid neutralize, this run I was not able too. My question: what signs do you all use in order to insure neutralization? Look for visible bubbles, pH paper?
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[*] posted on 3-10-2020 at 09:03


You did nothing useful by letting the acetone evaporate except trap the acids again and the newly formed salts from the base which adds an extra unknown element in the behaviour of your product.
In this field, that's called playing with your life.

Dissolve in the solvent, crash in water where you have dissolved NaHCO3. "Tweaks" such as adding the base directly to the solvent with the leftover water from filtering the crude product should only be a last resort / reserved for a time when you have more experience. They add their own problems anyway.

If you're afraid there are still occluded acids you can just repeat the procedure. The solvent is easy to find & cheap, the product doesnt dissolve in water. These are ideal conditions for you to practice.
Think how your questions would apply to picric acid ;)




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[*] posted on 3-10-2020 at 18:07


I had not even considered the new salts that would form, insightful observation. I dont really understand why you cannot neutralize directly in the solvent. Its my understanding that once you wash all the acid off the surface of your product, all that is left is the acid trapped within the products actual structure. So if the ETN is completely dissolved in a solvent that should release trapped acid and leave a solvent/acid mix. Why can this not be neutralized directly?
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[*] posted on 4-10-2020 at 05:35


It is of importance since those salts may sensitize or desensitize the EM. They might also be acidic and still ruin your batch, depress the fusion point etc.

You cant say reliably how much acid and how much water there is in your crude product (your original posts illustrates this quite well).
Is there really enough water to fully dissolve your base ? Where are the salts going to go if not water ? Wont a concentrated hot base partially hydrolize your product ?

Thoroughly washing the crude product shouldnt be an issue you're right. Acid loves water and it should be all gone if after filtering you wash your product with clean tap water.
But what's "thorough"? Is using the acidic crash water enough (hell no) or should you wash a couple of times with cold tap water. And... really, what's thorough when your product is insoluble ?

Anyway, back to a better question: WHY CANT PEOPLE JUST DO IT THE RIGHT WAY ? Why is it that people who performed a synth think they are experts after 4-5 times ?
If you want to get rid / dilute as much as possible the acids then you need a bigger volume.

Again, think how your questions would apply to picric acid. How do you remove one acid without destroying the other ?

PS: Earlier this week a friend of mine sent me a picture while in the hospital. I'm considering adding it to the "Life after detonation thread" even though it's more "life after ignition". So am I angry ? Sure as shit I am.




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[*] posted on 6-10-2020 at 04:57


Well isn't the way recrystallization works is allowing the crystals to slowly form and they will exclude most impurities substances during formation? Why is it then the stand is to dump in water rapidly producing your product BEFORE any acid has been neutralized.
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[*] posted on 6-10-2020 at 10:39


I guess it has to do with crystal size.

Break a crystal of inert material, nothing happens.

Break a crystal of an energetic substance. What could happen?

So, after preparation, crashing in water, washing with basic water and recrystallizing with a solvent and crashing out into (cold, basic?) water to induce fine crystal formation?

Btw, is it common practice to use vacuum filtering or only gravimetric filtering?
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[*] posted on 6-10-2020 at 10:50


If you wont listen (and you'd be right: I'm not a trained chemist) nor read the litterature (especially not that author who gets referenced in most EM books from other authors)

I hope you can you spend three minutes watching this video:
https://youtu.be/VwzwYahkJEs

You will certainly agree with the saying "if all you have is a hammer, everything looks like a nail"





The spirit of adventure was upon me. Having nitric acid and copper, I had only to learn what the words 'act upon' meant. - Ira Remsen
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