10digits
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Proper Neutralization of Nitroglycerine
Hello everyone,
This will be a small portion of a much bigger write up I'm going to do for a broader project. I wanted to make this post separate though since I felt
it was important enough in and of itself to deserve its own post. The following information may be common knowledge to most people, but I have yet to
see it described in any posts on the forums I have searched.
I noticed that all NG synthesis instructions instruct people to wash the NG thoroughly with copious amounts of water and Sodium Bicarbonate solution
until you get a neutral pH.
I conducted an NG synthesis a few days ago and came to the realization that it is very difficult if not impossible to fully neutralize in this manner.
The NG in this particular synthesis was produced via mixing 96% Sulfuric Acid with ~80% Red Nitric acid. The NA was actually a mixture of spare NA I
had lying around, one batch having been distilled under vacuum and the other distilled with no vacuum. After performing a titration I came up with
~80%. The nitration went smoothly and the yield was good. I digress so I'll post details about the reaction in a different thread.
Anyway, regardless of how many time I washed the product and put it through the separatory funnel, the pH wouldn't nudge from 2. This was well after 6
washes. I then decided to dissolve the NG in Acetone, much like when recrystalizing with ETN or PETN or any other of those lovely HEs. Adding about 5
ml of Acetone per 1ml of NG, I let it fully dissolve and sit for a few minutes. I then crashed this mixture into a 2000ml beaker filled with cool
Bicarb solution. There was mild bubbling observed and the NG dropped out of solution and consolidated on the bottom of the beaker.
After separating the NG from the water, I washed it "conventionally" a few more times with distilled water. I was pleased to see the litmus paper come
back with a pH ~7. Mission accomplished! The clean NG is almost done drying now and is nice and clear with a slight straw yellow color.
I hope this quick write up helps people in washing NG. It is a scary thought to have people sitting around with very acidic NG that they thought they
washed properly but never tested the pH. I should also note that I did not notice any loss of product during this process. I'm sure there was some but
it was minimal. I will definitely use this method from now on.
[Edited on 4-3-2013 by 10digits]
[Edited on 4-3-2013 by 10digits]
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Adas
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What about just putting solid NaHCO3 into the NG? It would be way more effective.
Rest In Pieces!
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killswitch
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Mixing granular solid material into an acidic nitric ester is a very bad idea.
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Hennig Brand
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I like the acetone idea and it’s not the first time I have seen it. I have seen that method mentioned either here or on the old Rogue Sci board.
Something else that works well is a bit of agitation, if it is done in a safe manner. Agitation exposes fresh surfaces of the NG blob to the bicarb
solution and keeps the bicarb solution well circulated so that the concentration of bicarb is kept high at the NG-bicarb solution interface. I have
done this with a small centrifugal table top fountain type pump and I had neutral NG in 10-15 minutes. Some sort of automated swirling machine might
be better, but I didn't quite get that one worked out. Also if the bicarb solution is warm, IIRC around 50C is used, it will greatly facilitate the
neutralization process. Warm NG is more fluid which makes it easier for the acids to be washed out.
The book "Nitroglycerine and Nitroglycerine Explosives" describes putting NG in a container with warm bicarb solution and then shaking the container.
This was in the laboratory preparation section I believe. It may be safe, but I don't think I am going to try that one. It is fairly simple for a
modern experimenter to rig up a little remote agitation after all. According to the text, neutralization was quite rapid by this method however. I
think it was stated that neutralization was achieved in 10-15 minutes, but I would have to go and check to be sure. I am sure that results would vary
depending on the size/configuration of the container used and on the quantity of NG to be neutralized.
The text also stated, in the section on purification of NG, that mechanical agitation was used in the past to neutralize NG, but that compressed air
was later used and that it was very simple to implement. Keep in mind that my digital copy states that the text was published in 1928. It seems like
air agitation would be very simple and safe and I am going to try it next. Can't believe I haven't tried it yet actually.
[Edited on 5-3-2013 by Hennig Brand]
"A risk-free world is a very dull world, one from which we are apt to learn little of consequence." -Geerat Vermeij
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SherlockHolmes
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Where can I download the book "Nitroglycerine and Nitroglycerine Explosives"?
Sorry for my english. I am not from England. Thank you!
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Hennig Brand
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A pdf of the book can actually be quite hard to find on the net. It can be downloaded from the forum library though.
"A risk-free world is a very dull world, one from which we are apt to learn little of consequence." -Geerat Vermeij
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SherlockHolmes
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But the Library Board does not open: (
Sorry for my english. I am not from England. Thank you!
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NeonPulse
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The method described above is my favourite way of washing the NG. It can be very time consuming to just swirl and it just is not a very good way to do
this. I have found that after dissolving in acetone then crashingit into the warm bicarb then using an areator to agitate the solution is best way to
go as many blobs are exposed and cleaned in a short period of time.saves Ph paper too! It sure is frustrating to spend ages on swirling to find the Ph
has not changed. The time saved is worth using this method I think.if there is an easier way I would sure like to hear about it. Neutralizing NG
totally is very important as we all know.
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bfesser
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<a
href="http://www.sciencemadness.org/library/books/nitroglycerine_explosives.pdf">Nitroglycerine and Nitroglycerine Explosives</a> <img
src="../scipics/_pdf.png" />
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