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Author: Subject: Utilize Nitroglycerin Waste Acids
Hennig Brand
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[*] posted on 24-4-2012 at 04:41
Utilize Nitroglycerin Waste Acids



When I was browsing through Naoum I came across this method to make use of the waste acids from nitroglycerin production. It was apparently not used much by industry even in the time the book was written, which the author claimed was because they got higher recovery from other more involved processes. For the hobbyist though this sounds ideal.

I tried it already with 75 mL of waste acid after a NG synthesis. The waste acids were allowed to sit for 2 or 3 days well covered and in the dark. Some more NG was collected at this point, and then the acid was used to nitrate toluene.


The following pdf contains the section from Naoum just described.



Attachment: Using Nitroglycerine Waste Acids.pdf (129kB)
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[*] posted on 24-4-2012 at 05:03


What was the concentration of acids u used and what was the ratio.
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Hennig Brand
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[*] posted on 24-4-2012 at 06:43


Maybe someone can help me with this. I calculated the approximate quantity of toluene to add by the following simple method. We know what the starting strength and quantity of nitric acid is, or we should know. The amount of HNO3 used in the esterification rxn, corresponding to the amount of NG collected, can be easily calculated from the stoichiometry. The HNO3 that is left can almost all be used to nitrate toluene to MNT.

The esterification rxn to produce NG is a reversible process while the nitration of toluene is not. I think any lower nitrates of glycerine are converted back to glycerine and the nitrogen used to produce MNT. As the concentration of HNO3 drops during the nitration of toluene there is de-esterification of the glycerine nitrates.

A better feel for the process and quantities used will come with experience as well I think.

I was asked to go through an example so here it is.

For stoichiometry I used:

3HNO3 + Glycerine ----> NG + 3H2O

HNO3 + Toluene ----> MNT + H2O

Density of NG = 1.6 g/cc
MW NG = 227.0865 g/mol

Density of Toluene = 0.8669 g/cc
MW Toluene = 92.1381 g/mol

Here is an example that I think is close to what I did in my trial run. 9 mL of NG was produced from a mixed acid made from 50g AN and 75 mL of 96% H2SO4.

Mass AN / MW AN = Moles HNO3 Available
50g / (80g/gmol) = 0.625 moles

Vol NG produced * Density NG = Mass NG Produced
9 mL * 1.6 g/mL = 14.4g

Moles NG Produced = Mass NG Produced / MW NG
14.4 g / (227.0865 g/mol) = 0.0634 mols

From Stoichiometry

3 moles HNO3 ----> 1 mol NG

Moles of HNO3 used = 3 * Moles of NG Produced
3 * 0.0634 mols = 0.190 mols HNO3 used

Moles HNO3 left = Moles HNO3 available - Moles HNO3 Used
0.625 moles - 0.190 mols = 0.435 mols HNO3 left over

From Stoichiometry
(I chose to go with an assumed 90% conversion based on HNO3)

1 mol HNO3 ----> 1 mol MNT

with 90% conversion
1 mol HNO3 -----> 0.9 mol MNT

moles HNO3 * 0.9 = Moles of Toluene needed
0.435 mols HNO3 * 0.9 = 0.391 moles Toluene

mass of Toluene = moles Toluene * MW Toluene
0.391 moles * 92.1381 g/mol = 36.0 g Toluene

Volume Toluene = Mass Toluene / Density of Toluene
36.0 g / (0.8669 g/mL) = 41.5 mL of Toluene

This calculation could be done in much fewer steps by combining the above calculations.

There are losses in both the esterification of NG and the nitration of toluene, so the amount of toluene needed is probably somewhat less.



[Edited on 24-4-2012 by Hennig Brand]
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[*] posted on 24-4-2012 at 21:52


Interesting. It was easy to utilize it with the information you share.
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[*] posted on 25-4-2012 at 07:49


Thanks, glad you like it. There really is a large proportion of acid that goes to waste, especially in most hobby scenarios. Most hobbyists do not have access to oleum and often not even fuming HNO3. There are methods that we use with less concentrated acids, or a nitrate and concentrated H2SO4 (forming HNO3 in situ). However, these methods make very poor use of materials compared to the industrial processes which use more concentrated acids and/or oleum. The equilibrium is not pushed nearly as far to the products side of the reaction when less concentrated acids are used. There is also more product lost which is dissolved in the larger volume reaction mixture in a hobbyist application.

It is true that for the hobbyist it is normally much smaller quantities of acid which is used, but it is still nice to make a useful product out of what would normally be a waste product.

I wonder if it would be safe to boil down the acid, after the MNT is collected, in order to recover the H2SO4? I don't think there would be any NG present, but there could be other dangers that I am unaware of yet. Maybe there is a simple treatment or chemical additive that could make this safe/doable.



[Edited on 25-4-2012 by Hennig Brand]
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[*] posted on 30-5-2012 at 07:06
Nobel's 808



I have been interested in plastic explosives lately. A very successful plastic explosive, based on NG, which came before the modern RDX and PETN based plastic explosives, was Nobel's 808. It was used extensively during WW2, especially by Special Forces for sabotage missions. The biggest disadvantage of the composition was that it was toxic to handle barehanded, producing horrible headaches. The material was apparently still in use, for various purposes, for several decades after WW2.

The following is a copy/paste from Wikipedia.

"One of the simplest plastic explosives was Nobel's Explosive No. 808, also known as Nobel 808 (often just called Explosive 808 in the British Armed Forces during the Second World War), developed by the British company Nobel Chemicals Ltd well before World War II. It had the appearance of green plasticine with a distinctive smell of almonds. During World War II it was extensively used by the British Special Operations Executive (SOE) for sabotage missions. It is also the explosive used in HESH anti-tank shells. Captured SOE-supplied Nobel 808 was the explosive used in the failed 20 July plot assassination attempt on Adolf Hitler in 1944."

I am having a hard time finding a reference, but I am told the following information came from an early, now obsolete document.

Nobel's 808
Nitroglycerine..........61.5%
Nitrocellulose...........16.0%
Calcium Carbonate....0.5%
Mono Nitro Toluene...22.0%

MNT could be produced from the waste acids from both the NG and NC syntheses. This material could be made very cheaply indeed.

[Edited on 30-5-2012 by Hennig Brand]




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[*] posted on 6-12-2012 at 02:46


nobel 808 is rdx not nitroglycerine
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[*] posted on 6-12-2012 at 03:50


Actually no ─ Hennig is correct!
MNT gave the comp. an almond odour and it wasn't to be handled without protective gloves because of the high NGl content . . .

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[*] posted on 16-12-2012 at 05:24


Does adding MNT to NG will help in plasticizing it . What are the ways to make plastic explosive from NG



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