While this method should work for any explosives that can be safely melted, I have chosen ETN because it is easy and cheap for me to acquire. My main problem with ETN is that when it is first synthesized there is virtually no way to remove acid trapped within crystals, short of expensive recrystallization.

I have devised a method of recrystallization (is this the term? the substance is going from a dissociated into a solid state) by simply melting well washed ETN and then pouring the molten ETN into quickly stirred, near freezing water. I got this idea when hearing about members who recrystallized at 80C where the ETN would be fully liquid anyways.

My first attempt at this method was as follows: I melted 39 grams of ETN in a hot water bath at 90C. As usual the ETN seemed to have held some water even after drying, as there were two layers. With this method this is not a problem. Once the ETN is fully melted I added about a gram of baking soda to neutralize any left over acid and stirred. There was a small amount of fizzing observed. Once this stopped I poured the ETN into 600 mL of ice water. The ETN settled to the bottom, THEN solidified. This gave me a hard layer of ETN on the bottom of the beaker.

The problem as I see it is that the ETN did not solidify in the water quickly enough. If the liquid were to turn into its solid for as it was introduced into the water could this method have the same effects as solvent recrystallization? To try and determine this I will be performing the same method again with rapidly stirred, temperature controlled water(time to break out the magnetic stirrer and extra thermometer). If this fails then injection from a syringe into the rapidly stirred water will be the next step.

Sadly this is not a full replacement for true recrystallization because unless the two layers were two different forms of nitrated erythritol, this way does not separate the less nitrated erythritol.

Nevertheless, even my solid chunk of ETN should be free of any acid. When the baking soda was stirred into the molten ETN it would have had plenty of time to react with any trapped acid. This would have been sped up by the extra heat as well. The recrystallization may be totally bunk, but do not rule out the molten neutralization.

This will "purify" the HE to some extent but I'd think the only method for a real purification is by using a solvent for recrystalisation.

I can't see how melting a compound and then rapidly cooling it down again with an immiscible coolant could have any effect on its purity. You need to get your ETN into SOLUTION and therefore give it near infinate surface area for washing away those last traces of acidity that would turn you prize into useless shit within days.

All you are achieving here using you method is making it more difficult to wash and giving it a larger surface area and making it MORE unstable. You are heating it! You are also inevitably handling partially frozen ETN.... BAD

Get yourself some MeOH. Put your dry or dry-ish ETN in a glass bottle and just cover with pure MeOH (damp ETN will need more MeOH) MeOH is CHEAP as shit!

Seal bottle and run under hot tap at 60C till all ETN has dissolved and solution has turned red. If you can't get it all in solution then under cold tap for a few minutes to cool, add more MeOH and repeat.

Once you have it in solution you pour it QUICKLY into another large bottle (use funnel) with about 5 times the volume of icy water and lots of free space. ALWAYS pour the MeOH and ETN into the cold water, NOT the other way round. Shake thoroughly and filter to give very pure and stable, finely powdered ETN.

The effect on purity is not the actual solidifying of the ETN but the fact that when it is melted no acid can be trapped in the ETN.

"""Once the ETN is fully melted I added about a gram of baking soda to neutralize any left over acid and stirred."""

Adding a basic component is as bad as adding acidic one. Thelasttrueone, read....

The effect on purity is not the actual solidifying of the ETN but the fact that when it is melted no acid can be trapped in the ETN.

Molten ETN can contain no acidity? ...well that's me corrected!

Frank: I used the word trapped ... not contain. In my mind there is a difference, but I will clarify for you. What I meant was molten raw ETN can be fully neutralized, unlike solid raw ETN. The acid and pure ETN may not seperate but the base will be able to react with the acid. This is the benefit, the ability to neutralize the acid that you could not be sure you were removing before.

simply RED: This I understand, however the basic component should be dissolved in the water when the ETN is introduced to it. The way my test went I can't be sure this happened. When I tested the pH of the water I washed the ETN with it was slightly basic, showing that at least some of the NaHCO3 was removed. Personally I would rather my ETN contain small amounts of base rather than any acid at all.

The recovered ETN is quite beige at the moment. though it was white when it first solidified. Decomposition due to the bicarbonate maybe? Oh well, I'll recrystallize it from my alcohol after watching it for a while for NOx fumes. I've not failed to purify my ETN I've simply found a way not to purify ETN!

The acid and pure ETN may not seperate but the base will be able to react with the acid.

thelasttrueone - I would have assumed your statement is only true if the base were to liquefy along with the liquid ETN.

By dissolving ETN as opposed to melting it, the acid dissociates and so does the base, allowing for neutralisation. If the base does not dissociate into the molten ETN, I don't see how it would effectively neutralise the acid present.

Ah a very valid point Alexires. I cannot be sure that the base dissociated but I saw no solid particulate when the mix was totally heated. This may be from the base melting or from the base dissociating in the water that I think was present. Actually, a quick look at wiki shows that my choice of base was terrible. The bicarbonate would have decomposed into sodium carbonate at the temperatures needed to melt the ETN.

Not to mention the fact that, even if this method worked like a charm, you'd still be losing product by melting it as I'm pretty sure ETN is going to start decomposing in its liquid state.

There is some merit to this procedure. Extreme high purity silicon for the semi-conductor industry is melt purified by slowly raising up a solid cylinder of silicon through a heated furnace zone. The impurities remain trapped in the melt zone, and when the silicon exits the heating area it crystallizes in a pure state.

Other chemicals similar to this can be purified by melting, which allows impurities to rise to the top, or settle to the bottom depending on density. For example, a tall steam jacketed column of meltable chemical works well for this.

I can't say if ETN will be purified this way, but it is not unprecedented to use the procedure.

You may well lose a good deal of product in recrystallization (What?!? My 95% yield went down to 63% after I recrystallized it!), but it you want the best purity, and safest product (residual acids can be very dangerous in explosives), recrystallization is the way to go. If you do successive recrystallizations by slowly reducing the volume of solvent you can obtain multiple batches of product. It takes more time and effort to do this, but you will not lose nearly as much valuable product.

If you do multiple batches of the same product, you can reuse the solvent from an earlier recrystallization. You will then not lose nearly as much product with each subsequent recrystallization because the amount of unrecovered product will remain about the same.

If you can reduce the pressure of your heated ETN you might be able to obtain a melt at a low enough temperature to avoid some, or all, decomposition.

Well I have come up with a procedure for doing this the right way if anyone wants to totally disprove me. Sadly it requires glassware that I do not have access to.

Would you care to share that with us? I can't really see how it would be a glassware problem, but if it was safe, and didn't ruin anything I could probably give it a shot. No promises. :cool:

Sorry to be so secretive. My schedule is ridiculous at the moment, leaving almost no time for posting and less for experimenting. When I said exotic glassware I meant exotic glassware. Of course you can differentiate from this as you see fit, but this is the optimal (in my mind) method.

The setup: A 1000mL round bottom boiling flask sitting in an ice bath with a magnetic stirrer below. Above this is a steam jacketed, pressure equalized addition or separatory funnel. Above This is a straight vacuum adapter. Lastly above that is a good stopper or possibly a thermometer adapter. Naturally this is all ground glass joints. All of this should be held by a LONG support rod or a bunch of helpful freshmen.

procedure:
1) put the magnetic stir bar in the flask, fill the flask with 750mL of distilled water.
2) close the stopcock and add 10g of raw ETN to the funnel.
3) close the system.
4) initiate the stirring and add salt to the ice bath.
5) start the vacuum, as much as you feel comfortable with your glassware.
6) send heated steam through the funnel's jacket and slowly increase heat until all ETN is melted.
7) open stopcock halfway to send the hot ETN into the cool water.
8) stop vacuum, shut off heat and disassemble the system.
9) filter and rejoice.

Now, I have zero experience with any of this kind of glassware. If I have outlined anything dangerous, stupid or just wrong please don't hesitate to say so (and maybe insult a little if thats your game). The hardest part to acquire of all this is of course my crazy and quite possibly non existent ... yet ... funnel. The ETN amount is very small for safety and yet large enough for good observations. If someone could do this experiment I would be forever in your debt.

Well, I do have flasks, vacuum adapter, vacuum source, sep funnel, stands, etc.

But I'm not sure about how a person would improvise a "steam jacket"...

I guess you could just heat it with a bunsen burner (blowtorch) or maybe a heating coil if you have one. A steam jacketed piece is a double walled piece of glassware that has holes to inject steam. Sort of like a condenser. Like I said I have never seen anything that was considered steam jacketed besides a small micro scale distillation apparatus so if you really wanted one you would most likely have to get it custom made. You have to make sure the funnel you use is pressure equalized like the one on this page (also has a way to improvise) http://designer-drugs.com/pte/12.162.180.114/dcd/chemistry/equipment/simple2fancy.html

I guess you could just heat it with a bunsen burner (blowtorch)

This is not likely to happen. I'll leave it for someone else to put a torch to a glass chamber of ETN. Even if this didn't kill me it'd wreck my teflon stopcock.

Even if this didn't kill me it'd wreck my teflon stopcock.Spoken like a TRUE lab-rat! LOL

Messing up ME is one thing... but fucking up my teflon SC- NO WAY!!!:mad:

You gotta respect that, IMO.:D

But at the end of the day, it would seem that using water/base for neutralizing the ETN wins out, for numerous reasons. But the idea IS interesting, none the less.

It might not be so hard as you think... I have a steam jacket made from an old plastic graduated cylinder, one of the big ones. It has a rubber stopper at the top with a single hole, and it is split. The rubber stopper goes over a special flask with a glass stem, and the jacket plugs right in. The steam sprays on the top of the tube, through regular rubber tubing, also into the stopper. The bottom of the jacket is plugged with a stopper that is taped on. A length of tubing drains into the sink from there.

You could do the same for a p-eq funnel with a plastic bottle large enough to fit around it. The glass arms at the sides will require a bigger bottle, but it is doable. Get two nice big rubber stopper and cut a hole large enough to fit snugly around the funnel neck (I assume you will be using a standard taper glassware version) on top and bottom. Slit both stoppers so you can stick them on easy from the side. It may be a little harder putting the stopper on the bottom without getting in the way of the stopcock depending on the model you have.

Connect the jacket to the top stopper, add a second stopper to the bottom *before* your stopcock, and add in the necessary holes and hoses where needed, etc. Yes, this might leak a little water because the stoppers are slit, but that should not affect a well connected glassware setup.

Those plastic graduated cylinders are made from a nice thick plastic, so the thing has held up well over the years. I would suggest maybe buying one of those sport water bottles, or rectangular liquid storage bottles for the fridge. Some of these have a heavy thick walled plastic. If the plastic is too flimsy you will have a hard time keeping the stopper in.

Mega: I had exactly the cylinder you speak of until recently, when I threw it out, due to being stained and damaged by acetone. :(

I think I get the gist of the scheme you're describing, but I'm a little fuzzy on the details. Maybe you could provide a diagram or picture... or I could draw one and you could tell me if it's something like your description. All I know is that the jacket will have to be tapered as rubber stoppers are much smaller than the widest part of the sep funnel.

I assume the steam is generated from a simple flask of boiling water? Nothing fancy? :p

Yea thats how one goes about producing steam. Thank you so much for making that comment about acetone! You probably saved my large cylinder from a similar fate.

Indeed. It was a beautiful thing before it turned patchy milky white in places and stuck onto any dirt/residue it was exposed to.

This seems like kind of a fun project, so I think I may take a crack at it once I have some time.

Thelasttrueone: Could you maybe post/ email me a diagram of the setup? Because seeing as I am about to replace my broken apparatus soon, I may even try what you describe, once I have my lab back up and running. However it will be a few months until I can even dream of affording such apparatus. The melting method indeed has some merit, maybe you could cuudely examine its possibility if you were to cast some ETN in a transparent container, after all, you DO have experience casting ETN if I remember correctly.