Sciencemadness Discussion Board - Cheapest way to get the highest amount of ETN?

Cheapest way to get the highest amount of ETN?

Weeblordd - 4-2-2024 at 08:09

I have a distillation setup with a tap water aspirator and some more labware, I can make nitric acid from sulfuric acid and a nitrate salt if needed, available to me are:
1. NaNO3 >99% 4.5€/kg
2. Ca(NO3)2 tetrahydrate >96% 1€/kg
3. KNO3 >99% 5€/kg
4. NH4NO3 >98% 6€/kg (via 1(NH4)2SO4 + 1Ca(NO₃)₂ = 2NH4NO3 + 1CaSO4)
5. (I can produce nitric acid too btw, would distill battery acid to get 80% H2SO4 and mix it with nitrate and then distill the product to get nitric acid I guess)

I would like to get some help from experienced people, I aim for the method that can get me the highest yield of ETN for the cheapest price. I can make nitric acid if the yields are much better. But I don't know if the yields are better, this would be my first time trying the synth.

I've heard people say that in a lab setting, dry ammonium nitrate is the best, producing the highest yield. KNO3 makes the nitration solution super thick. NaNO3 barely produced any ETN. As mentioned, I can use NH4NO3 but I'd prefer to use it for AN-based secondaries. Perhaps for me it'd be cheapest to make nitric acid from calcium nitrate tetrahydrate since it's 1€/kg?

I've also found this patentthat states this "stabilization of the nitrated product by dissolving it in a water soluble solvent such as alcohol or acetone, adding a weak alkali such as sodium or ammonium carbonate, and then forcing the erythritol tetranitrate out of solution by adding water. This method of stabilization gives a product of excellent stability superior in this respect to the erythritol tetranitrate described in the literature." So I guess you can dissolve ETN in isopropanol, add sodium carbonate, and ETN of excellent stability will precipitate out. Is this worth doing?

fx-991ex - 4-2-2024 at 08:52

As for stabilities you can also recrystalized it with urea after or instead the carbonate, urea is a NOx scavenger.

The decomposition product which are NOx usually turn to nitric acid in surrounding humidity and it accelerate the decomposition.
Urea will turn those NOx into CO2, N2 and H2O instead. Carbonate also neutralize the NOx/acid but it leave the behind as a salt.

Weeblordd - 4-2-2024 at 09:34

That's good to know. What happens when you recrystallize ETN with urea or carbonate? the carbonate or urea molecules get bound to molecules of ETN? or do they come out as a double-salt (might sound stupid but go easy on me I'm a beginner in chem still)? or are urea molecules mixed with ETN molecules at a molecular level? Can someone explain?

DennyDevHE77 - 4-2-2024 at 10:32

The best yields in the synthesis of ETH are obtained when using almost anhydrous (>95%) nitric acid and acetic anhydride, or nitric acid and sulfuric acid of the same concentration.

When using nitrates in different ratios, most people here, and me too, have had yields varying from 40 to 65% on average. ETN is unfortunately much less profitable than PETN. I can also assure you that ETN is also obtained when synthesizing with potassium nitrate and sodium nitrate. But it is very difficult to work with such a mixture (unlike ammonium nitrate) because of the precipitation of the corresponding sulfates. But ETN is still obtained. And yes, your calcium tetrahydrate can be heated at 200C, and get anhydrous calcium nitrate. However, I would not recommend distilling nitric acid on ammonium nitrate and calcium nitrate, in the first case nitric acid is weaker, and in the second case you will have to deal with gypsum (and nitric acid is also often weak).

About stabilization. Since you are new to chemistry, here is a brief summary. PETN, ETN, Nitromannite, all these are nitroesters, esters of nitric acid with alcohols, having O-NO2. Nitroesters are inherently alkaline substances. When you synthesize them, especially solids, some of the acids used for synthesis are trapped in the crystals. The acids then cause autocatalytic (self-accelerating) decomposition of your product. By dissolving, for example, PETN in acetone, you "release" the acid from the crystals, and can neutralize it with a weakly alkaline agent (baking soda, ammonium carbonate), although often neutralization occurs already when you pour the solvent with nitroether into water (together with baking soda). Nitroesters without stabilization can exist for months or even less. Once the acid is removed from them, they can live for decades.

Nevertheless, in industry, even to already pure, acid-free nitroesters (usually to smokeless powders) stabilizers 1-2% are added, as it is said above they are necessary for NOx binding. In addition to urea, its derivatives centralites, accordites, diphenylamine (not everywhere), nitrosodiphenylamine, nitrodiphenylamine, ethylphenylurethane, triphenylamine or butylphenols are used.

But I don't think it matters to you, you are unlikely to store your products for >30 years.

Also, nitroglycerin, EGDN, and other liquid nitroesters do not have to be dissolved in anything. It is usual to take some slightly alkaline water solution, add it to the nitroether, and stir it with compressed air.

Actually, ETN can also be melted and mixed with a soda solution, but I would not do that.

And of course such purification-stabilization applies mainly to nitroesters. Trotyl, picric acid, nitrobenzene, and other aromatics, as well as RDX, HMX and other nitramines are not afraid of acid. They can even be recrystallized from acids, such as ETN from isopropanol. Although in industry they are of course cleaned. Hexogen is not afraid of acid, but if it is not cleaned, over time it may begin to release it from the crystals, which can lead to the destruction of other substances or corrosion of the ammunition.

And in the photo below, ETN after just one night of storage. It was obtained from anhydrous acids at 30C, as a result it fell out in the form of a semi-molten mass containing a lot of acid inside, besides, I washed it very weakly

Storing nitroesters without cleaning can lead to discoloration, release of nox, stink, spontaneous ignition, or even a flash/explosion if their amount is significant.

[Edited on 4-2-2024 by DennyDevHE77]

ManyInterests - 4-2-2024 at 11:57

I am back to making ETN and I did look at this thread for more information and new methods: https://www.sciencemadness.org/whisper/viewthread.php?tid=15...

Since I successfully made good, pure NH4NO3 I decided to go that route instead of my usual nitric acid route because nitric acid has always been tougher and more expensive for me to make. When I saw that thread I thought of giving it a go.

I did mostly what the other person did. Dissolved the amount of ammonium nitrate in the sulfuric acid and then I kinda went overboard with the cooling. I used my usual method of freezing the nitrating mix in a salt-water ice block (putting salt-water around the beaker and then putting the whole lot in the freezer). This worked to get the temperature to -15C instead of the person's -20C instructions (I haven't been able to get temperature that cold yet. Maybe my freezer isn't good enough?) I started to put the erythritol in it by the spoonful instead of all at once since that did make me nervous when I saw the video. But the reaction was quite mild and it was heating far too slow, which is not something I was expecting. I removed the beaker from the ice block and I even had to bring the whole thing indoors since it is too cold outside for even that heating to happen.

I was fearing a runaway, but the temperature rise was not very fast and no temperature spikes occurred. Putting the beaker back in the ice block did cool down very quickly, meaning there was no runaway occurring to prevent.

I had the whole thing for 2 hours and 20 minutes before crashing the sludge in water (and it was VERY thick) and then began the long and tedious process of filtering and washing it. I used almost a gallon of water, 1.2 liters of sodium bicarbonate water and washed that with even more water to clean out all acids.

I think the excessive cooling caused a problem with the nitration, since I was hoping to get 23g out of a 10g starting erythritol but I got 18.5g of crude ETN (albeit it is very acid free. I might lose a little after recrystalization, but I don't expect to lose much).

Although I was disappointed, that yield was still the best I ever got. Since previously I would get 1.5 or 1.6 at the absolute most, and that was using 75% nitric acid.

Sir_Gawain - 4-2-2024 at 20:46

I had a runaway once; I cooled the sulfuric acid/AN to about -15 C, then added the erythritol fairly fast. The temperature wasn’t too high, so I figured it wouldn’t need further cooling. I stupidly left it (this was several years ago) and came back to a cloud of nitrogen dioxide and the plastic wrap on the beaker melted. Even screwing up this badly didn’t cause an explosion.

dettoo456 - 5-2-2024 at 08:37

The NH4NO3/H2SO4 is the cheapest and most effective method but only if you have access to bulk-pricing (<$0.5/lb) and that is almost impossible these days unless you own a working farm.

KNO3 is very cheap and available and that’d be the second best option, especially over the Ca or Mg Nitrate methods which would be extremely annoying (drying the hydrates is finicky).

If you can get ahold of bulk 68% Nitric, then I’d recommend that, but it’s hard to find, especially in EU.

And Erythritol is available in bulk from baking suppliers, Jedwards (US supplier) sells a 55lb bag for $90 for example - I’d pick one up if you have cash to burn.

Urea should be used as a stabilizer for recruit, and potentially phenols like Guaiacol or Curcumin could be added directly to the final powder to aid in NOx scavenging.

ManyInterests - 7-2-2024 at 03:06

Quote:

I had a runaway once; I cooled the sulfuric acid/AN to about -15 C, then added the erythritol fairly fast. The temperature wasn’t too high, so I figured it wouldn’t need further cooling. I stupidly left it (this was several years ago) and came back to a cloud of nitrogen dioxide and the plastic wrap on the beaker melted. Even screwing up this badly didn’t cause an explosion.

I had a single runaway with ETN once. I think it was due to simply letting it warm up too fast after adding all of the erythritol. Even though I did it when it was cold and gradually. thankfully it just burned out and no pop or explosion.

Weeblordd - 7-2-2024 at 06:51

Huge thanks for all the info. Extremely useful and helpful.

Quote: Originally posted by DennyDevHE77

When using nitrates in different ratios, most people here, and me too, have had yields varying from 40 to 65% on average.

May I ask, what's the average yield for sulfuric acid and nitric acid nitration of erythritol? Tbh since I wanna go as cheap as possible, I think I would choose the ammonium nitrate and sulfuric acid route. Price-wise I don't really like the fact that you have to use sulfuric acid twice (in production of nitric acid, and in production of ETN). P.S. I live in EU where getting your hands on some nitric and sulfuric acid is extremely difficult. Also in my country KNO3 is cheap but producing a kilogram of NH4NO3 is like 1-2eur more expensive than buying a kilogram of KNO3, and as many people said NH4NO3 is best, I guess I'll go with that.

Quote: Originally posted by ManyInterests

I used almost a gallon of water, 1.2 liters of sodium bicarbonate water and washed that with even more water to clean out all acids.

You used
Erythritol:10g
H2so4:100g = 51cc
Nh4no3=40g
Etn:23g
?

and you used a gallon of water and 1.2L of sodium bicarbonate solution? Isn't that like 10 times overkill? I'd use that amount of liquids to wash like 200g ETN tbh, maybe even more, haven't attempted the ETN synth yet ever though.

ManyInterests - 9-2-2024 at 19:56

I did try that synthesis twice, but I did not get 23g or anything approaching that. I am really wondering why I am not getting that yield as I tried to follow what the other did as much as possible. Could be bad luck.

For nitrate salts, it depends on what you want to do. NH4NO3 has one advantage over NaNO3 and KNO3 in that it readily mixes with sulfuric acid and doesn't gel as easily. I heard that using ammonium nitrate for making nitric acid is not ideal because a byproduct of distillation is ammonia that could neutralize some of your product. This is why I use either KNO3 or NaNO3 for nitric acid.

I can make large quantities of NaNO3 very easily and very cheaply since sodium carbonate is very cheap and if I cannot find the cheap Arm & Hammer brand, it can be very easily made from very cheap and readily available baking soda.

Edit: The reason why I wash the ETN so much (and I haven't used bicarbonate water in the previous two times because of I washing out the bicarbonate might be mroe trouble than it's worth) is because ETN is effectively insoluble in water, and any residual acid in it can cause to degrade badly.

The first time I made ETN so many years ago I did wash my ETN, but I didn't wash it enough, and even though I did recrystalize them once, they STILL degraded (yellowed badly) when I loaded them into blasting caps. at first I thought it was the NHN reacting badly with it, but this turned out to not be the case. After that I simply decided to go overkill with washing to make sure no acid is left over.

[Edited on 11-2-2024 by ManyInterests]

Weeblordd - 12-2-2024 at 08:15

Idk tbh, probably chemistry gods weren't with you at the time of synthesis. For real though I wonder what's keeping you away from the 23g.
Is it really true that NaNO3 and KNO3 gel up so much that you can break glass stirring rods when trying to stir it?
And that's surprising tbh

DennyDevHE77 - 12-2-2024 at 08:26

It simply precipitates potassium and sodium hydrosulfates, which are poorly soluble in the sulfur-nitrogen mixture. So, for example, when you pour ammonium nitrate with sulfuric acid, already at room temperature you get a homogeneous solution, while when boiling sulfuric acid and potassium or sodium nitrate, you can not get a homogeneous solution.

ManyInterests - 12-2-2024 at 16:15

Quote:

Idk tbh, probably chemistry gods weren't with you at the time of synthesis. For real though I wonder what's keeping you away from the 23g.
Is it really true that NaNO3 and KNO3 gel up so much that you can break glass stirring rods when trying to stir it?
And that's surprising tbh

It could be any number of factors. But last Saturday the same with 120g of erythritol and the same ratio of sulfuric acid/H2SO4 and ammonium nitrate/NH4NO3. I think I got a larger yield, but I am still drying it. I am confident it is NOT 2.3g to 1g of erythritol, but I hope it is better than the other time I went that big.

I honestly think that the larger it is it might need more time to nitrate. In the case of my latest attempt, I added all the erythritol at once and stirred it until it dissolved. It actually took quite a while to dissolve since the erythritol sometimes lumped up when I put it in there, but I do believe I got it all dissolved. The other thing is that I gave it a lot more time to nitrate. In the video of the PETN1933 where he got his super good yield the whole thing was 110 minutes long. For me I gave it 2 hours and 46 minutes (166 minutes). Even that might have been too little, but if it needs more time to nitrate, then that should have a better yield.

I hope it will be fully dry by tomorrow or Wednesday for me to get a good measurement. After that I'll need to do my recrystalizations of the whole thing since I would have a few hundred grams of unrecrystalized ETN, and I want to give them a double recrystalization with sodium bicarbonate and urea to act as NO2 scrubbers and make sure I have no more residual acids left.

Quote:

It simply precipitates potassium and sodium hydrosulfates, which are poorly soluble in the sulfur-nitrogen mixture. So, for example, when you pour ammonium nitrate with sulfuric acid, already at room temperature you get a homogeneous solution, while when boiling sulfuric acid and potassium or sodium nitrate, you can not get a homogeneous solution.

Yeah, that is the major advantage of using ammonium nitrate. If you're using it to make a nitrating solution, it is a much smoother and easier process.

When I did the one and only ETN synthesis I did with KNO3 made me never want to use KNO3 ever again for it. Now I should have ground up the KNO3 into a finer powder (with the consistency of powdered sugar) and dried it even more to make sure it is fully dry.

But what happened is that it really didn't want to mix very well and fully dissolve into the sulfuric acid. I then put it in the freezer to cool down and... yeah, that's when it became a gel that was so tough that It really did almost break my glass stir rod. How I solved the problem is to use multiple glass stir rods to make the whole setup stronger to stir. But it was bad. Really bad. Like out of 5g of starting erythritol I ended up with 3g of ETN, and it felt kinda off, even after recrystalization, so I never used it.

If you have access or can make a decent amount of HNO3, that is good. If not, AN is acceptable.

ManyInterests - 13-2-2024 at 10:35

OK so an update. I did get 220.5g from the 120g of erythritol that I started out with. I will attribute this to longer nitration time and using a wider bowl that made fully dissolving everything easier. I will try again with the same thing, but I will give it an additional 45 minutes of time to nitrate to see if that makes any difference.

ManyInterests - 20-2-2024 at 03:31

OK, so I recrystalized all of my previous yields (10g, 100g, and 120g) where I got 15g, 124g, and 220.5g respectively. I did it in 600ml of hot acetone. After drying, I got a final yield of 300.51g pure ETN out of 359g of crude. I am not sure where all the impurities where from, but the smart money suggests the 2nd batch I made.

I'm going to experiment with the remaining erythritol that I have. I am actually curious to see what I can do to maximize ETN yields with larger batches via AN. I'm going to try to sift the erythritol into the nitrating mixture to see if it'll prevent lumping, too.

And like I said, I will try to give them longer nitration times to see how much of a difference it makes.