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Uriel
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[*] posted on 1-2-2017 at 07:28
Ethylnitrate


Ethylnitrate synthesis :

Hello everyone !
I've made a synthesis of Ethanol nitrate, but the way is quite difficult and dangerous.
So to prevent people to have any accident, I share my recent experience here.
I've made three attempt : the first two lead to a runaway and the third worked correctly.

- First failure: I added 21g of 90° household alcohol by drops to a nitrating bath at 0°C composed of 70g of HNO3 58% with 110g of H2SO4 96% during about 15 minutes.
The vessel was immersed in an ice-water bath.
The temperature slowly rise to 10°C and above at the end. I had not yet added the last drops that the temperature rise faster from 12°C to 14 and 15°C. Bubbles appeared and a little bit of red smoke (NO2).
I somewhat panicked and poured the liquid in 500mL of coold water. The mixture continued to bubble and I could not recover anything.

- Second test : I put about same proportion of acids in the freezer at -18/-20°C.
I quickly added the 21g of alcohol (less than 2 minutes), and the temperature has risen, risen, risen, has exceeded zero, 5°C and 10°C in few seconds to finish in a geyser of acids reaching 80Cm high (in a cylindrical container).
Thanks to god, it did not explode ! But I had put some protections for this possibility...

- Third test : I only use 12g of 90% alcohol mix with 3,5g of 96% sulfuric acid. This mixture was placed in the freezer with the same proportion of acids (70g/110gH2SO4). (Still at -18*-20°C).
I added about 1mL of acidified alcohol per 20 seconds during 6 minutes.
The temperatures rise slowly to achieve -0,5°C at the end of addition. She don't move during few minutes. I keep the magnetic stirring. Three minutes after the end of the addition, the temperature is still below 0°C.
I've decided to separate them, so I poured the mixture into a separatory funnel, and let is about 10 seconds. The ethylnitrate phase clearly appear and I opened the flux to collect the nitrate. I pour it in 60mL of water saturated with sodium bicarbonate.
I recovered 12g of pure ethylnitrate (+/-0,2g) from 12g of 90% alcohol (about 10,28g of pure ethanol : 12x0.8566 for 90% volume).

The burn test is quite « grey », in reality blue/yellow/gray.
The explosion can be see here https://www.youtube.com/watch?v=YIdFCzLEyZo

I want to warn you that this synthesis is more dangerous than nitroglycerin because the temperature is difficult to control, the solution runs at around 15°C and traces of NO2 lead to degradation catalysis. The danger is particularly linked to the fact that the liquid floats above. So the nitrate explodes more easily than nitrations in which nitrate is dissolved (like EGDN).
The nitration should not take more than 15 to 20 minutes (I advise strongly less than 15 minutes) because then the nitrate begins to oxidize.
I guess that my second attempt did not explode because I was stirring quickly that there was not a floating phase, as at low speeds.

Have a nice day !




[Edited on 2-2-2017 by Uriel]
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[*] posted on 1-2-2017 at 10:14


OK, we thanks. But is some practical reason, why preparation this substance ? Thus on field of energetic materials ? .....:cool:....LL



Safety explosive Alfred Nobel 1867. Safety ecologic detonator Dr. Liptakov 2015, inventor of CHP
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[*] posted on 2-2-2017 at 02:38


Your third test mentions no quantity of the mixed acid.

Off the cuff, your mixed acid looks rich in nitric which lends itself to runaway. Were you following a published synthesis or winging it? You don't mention any nitrous acid suppressing method. -20C sounds too low. When doing an esterification or a nitration if you take the temperature too low you store up unreacted raw material in the mixture and the reaction can behave like you dumped in a lot at once.

90% ethanol contains a lot of water, it's a small light molecule so that 10% content amounts to something like a quarter or a third of the molecules being water. It would certainly be worth drying it properly, that may reduce the thermal rise when it's added to the mixed acid a lot.
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Magpie
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[*] posted on 2-2-2017 at 10:07


Quote: Originally posted by Marvin  
Were you following a published synthesis or winging it?


This compound is an explosive. Did you follow a published procedure? If not, why not?




The single most important condition for a successful synthesis is good mixing - Nicodem
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Uriel
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[*] posted on 2-2-2017 at 12:59


Yes, I followed a published synthesis but the first time without acidifying the alcohol. And the time of nitration is not clearly exlain and it is a big forgetfulness (really oblivious).
I haven't urea to delete the NO2 as in some nitrations.
Marvin :
I can guarantee you that nitration can be done under 0 or -5°C like PETN. But you are right the reaction can behave like you dumped in a lot at once (with rising temperature), I think it's happend in the second test.
You said : " that may reduce the thermal rise when it's added to the mixed acid a lot" yes, that why I hadded 3.5g of sulfuric acid to the alcohol, it's helps to reduce the thermal rise.

I copy it here but I propose you NOT to follow the time indicated, to see shorter and really less in quantities :

"Author: Fly
Procedure: Prepare a nitrating mix using 260 ml 65% HNO3 and 300 ml 96% H2SO4. Slowly add the H2SO4 to the HNO3 with cooling and constant stirring. Let the nitrating mix cool down to 0°C in a refrigerator. In another container place 160 ml of pure ethyl alcohol and slowly add 16 ml 96% H2SO4 with cooling and stirring. Let this mix cool down to 0°C as well. Prepare a salted ice bath and place a 1L or larger beaker in it. Pour the cold nitrating mix into the beaker, place a thermometer in it and begin the addition of the cold ethanol mix. Keep stirring the mixture, adjust the rate of addition so that the temperature stays around 5°C, do not allow the temperature to rise above 10°C. When the addition is complete, continue stirring the mixture for another 5 mins. Transfer the mixture into a separatory funnel and let it stand for 15 mins. The crude ethyl nitrate should separate out, drain the acid portion. The separation should not be carried out for more than 15 mins., after that the product might start oxidizing. The crude ethyl nitrate is washed by 300 ml of cold water (shake the mixture thoroughly in a plastic bottle). Repeat the separation and wash the product again with 300 ml water, then add a small amount of NH3 solution to the mixture and shake it again. Repeat the NH3 addition until the solution is pH neutral. Repeat the separation and washing steps, check that the product is clear and colorless. Now the product can be finally separated, dried over CaCl2 and filtered. The product obtained in this way should not be stored.  "

My conclusion (with this products) is :
the duration of the operation, from the first drop of alcohol paid until the separation should take less than 15 minutes...

[Edited on 2-2-2017 by Uriel]
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aga
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[*] posted on 2-2-2017 at 13:32


Is good. Me like.

Like video also.




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Magpie
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[*] posted on 2-2-2017 at 17:41


FYI there is a procedure for ethylnitrate in Cumming (forum library). Note the recommendation for use of a safety screen.

[Edited on 3-2-2017 by Magpie]




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