The melting-point issue in nitroglycerin home-manufacture
M. Gauldoth, Mon Feb 13 2006, 04:55PMThe first trial tonight I made a little nitro following the guide of Home Workshop Explosives by Uncle Fester. I used fuming nitric acid produced by water bathed potassium nitrate + sulfric acid. One unexpected thing happened when the following instructions was carried out.
The addition of the glycerin to the acids should take about 25 minutes, adding ten portions of glycerin of about 5ml each. The temperature of the reaction mixture should be watched during the addition of glycerin. It should not be allowed to rise above 50 degree F (10 degree C). If it gets too close to this temperature, the additions of glycerin should cease, and the mixing continued with the vessel nestled in the ice bath until the temperature drops back down to around 40 degree F (4 degree C).
My fuming nitric-sulfric acid mixture was below 10 degree C when each time I added glycerin. Clear sticky crystal was gradually produced. During stirrings, abrupt temperature rise was observed, the maximum being 30 degree C, though it dropped as quickly as it rose. When the reaction ends, I was presented a jelly mixture of acids and the said crystal. I thought I failed -- but as the jelly warmed up a bit in 300 ml water the crystal melted and became a liquid emulsion forming a distinct layer below water -- the expected form of crude nitro. It amounts to 2 ~ 3 ml, approximately 10% of the expected yield (I used half amount of reagents).
My hypothesis is that the temperature in ice bath is below the melting point of nitro, so the early-made nitro solidified and insulated remaining glycerol from the acids. Stirring brought glycerol and acids to rapid contact hence the uncontrolled temperature rise.
Is my view correct? I would like to know how you people handle this. I'm making another batch tomorrow and I don't want to suffer through that again.
One more question; glycerol loves sucking water from the air, the sample I used swelled more than 5ml during the addition. Is there anyway to prevent this?
Most gratefully,
M.G.
Re: The melting-point issue in nitroglycerin home-manufacture
Steve Conner, Mon Feb 13 2006, 05:12PM
Hi M.G.
Nitroglycerin is an extremely unstable and dangerous high explosive, and as such, it's probably illegal for you to make. The forum main page specifically says that we don't allow discussion of illegal explosives.
The fact that you mention "unexpected things" happening during the process is very worrying indeed, especially since Uncle Fester is hardly a world-renowned explosives expert and his writings are known to contain errors. I can imagine the next "unexpected thing" that happens will involve parts of you getting blown off, so I'm going to lock this thread, and I highly recommend you don't try making any more nitroglycerin.
Steve Conner, Mon Feb 13 2006, 05:12PM
Hi M.G.
Nitroglycerin is an extremely unstable and dangerous high explosive, and as such, it's probably illegal for you to make. The forum main page specifically says that we don't allow discussion of illegal explosives.
The fact that you mention "unexpected things" happening during the process is very worrying indeed, especially since Uncle Fester is hardly a world-renowned explosives expert and his writings are known to contain errors. I can imagine the next "unexpected thing" that happens will involve parts of you getting blown off, so I'm going to lock this thread, and I highly recommend you don't try making any more nitroglycerin.
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