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Author: Subject: Do Walgreens Instant Cold Packs still contain Ammonium Nitrate?
Hurricoaster
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Do Walgreens Instant Cold Packs still contain Ammonium Nitrate?

Yesterday, I read this thread, and decided I would try to purify some ammonium nitrate. I bought some instant cold packs from Walgreens, and emptied the prills into an old water bottle. I then added 300ml of water to a beaker, and started adding the prills until they wouldn't dissolve anymore (it turns out what I thought was un-dissolved ammonium nitrate was actually a lot of anti-caking agent, but oh well). I then added another 200ml of water to dissolve the rest, then filtered the solution. The coffee filter caught all of the anti-caking agent, and I washed the beaker out, then put the filtered ammonium nitrate solution back in. I put this on a hot plate on medium-low heat, so that I could see water vapor coming off, but the solution did not come to a rolling boil (my hot plate doesn't let me choose an exact temperature, so I wanted to be sure I didn't boil off the ammonium nitrate). I left it this way overnight.

When I came back in the morning, all of the water was gone, and at the bottom of my beaker was a hard, white substance. I had to pound it with a butter knife to break it apart. I took a chunk of this, and tried to burn it. Instead of burning, though, it just melted! Is ammonium nitrate supposed to do that? I thought it was supposed to burn on its own, but maybe I'm wrong. How can I make sure what I have is really ammonium nitrate? Alternatively, can anyone else confirm that the Walgreens instant cold packs still contain ammonium nitrate?

Here is a picture of the resulting substance, if that helps:

MrHomeScientist
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Last time I bought them several months ago they did. The other possibility is urea.

I don't think ammonium nitrate burns on its own usually. If you can, convert it to potassium nitrate and mix that with an equal volume of sugar to see if that burns. Or try adding a solution of a base to your suspected ammonium nitrate, and it should evolve ammonia gas. I'm not sure how urea would react though, so those tests might not be specific.
Maroboduus
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Check the melting point. I'ts only around 160-170, you can do that with a MP tube and thermometer in a flask full of cooking oil.

gdflp
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 Quote: Originally posted by MrHomeScientist Last time I bought them several months ago they did. The other possibility is urea. I don't think ammonium nitrate burns on its own usually. If you can, convert it to potassium nitrate and mix that with an equal volume of sugar to see if that burns. Or try adding a solution of a base to your suspected ammonium nitrate, and it should evolve ammonia gas. I'm not sure how urea would react though, so those tests might not be specific.

Urea will similarly release ammonia upon reaction with a base. The reaction of an alkali nitrate with sugar however, should be characteristic.

camerican
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Somewhat off-topic, but CAN from Rival brand instant cold packs is an acceptable source of AN. The process of dissolving the AN and evaporating the solvent is much less tedious if alcohol is used instead of water.
AngelEyes
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A different test is to simply dissolve an appreciable amount of what you suspect to be Ammonium Nitrate in water. It's an endothermic reaction and the beaker / glass / whatever will cool down as the nitrate dissolves, often quite markedly. Might be easier than melting in a flask of oil...

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XeonTheMGPony
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 Quote: Originally posted by AngelEyes A different test is to simply dissolve an appreciable amount of what you suspect to be Ammonium Nitrate in water. It's an endothermic reaction and the beaker / glass / whatever will cool down as the nitrate dissolves, often quite markedly. Might be easier than melting in a flask of oil...

So does :
Ammonium sulfate
Urea
Cal Ammonium nitrate mixtures
and quite a few others that I can not recall the name off hand
Brom
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You could add some hydrochloric acid and see if it reacts with copper to determine if it is a nitrate salt. If it tests positive for nitrate and also releases NH3 upon addition of NaOH it would have to be ammonium nitrate
Maroboduus
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 Quote: Originally posted by AngelEyes A different test is to simply dissolve an appreciable amount of what you suspect to be Ammonium Nitrate in water. It's an endothermic reaction and the beaker / glass / whatever will cool down as the nitrate dissolves, often quite markedly. Might be easier than melting in a flask of oil...

1: Put the MP tube tied to the thermometer in the oil.
2: heat the oil

Slightly less work than making french fries.

If you're a Tater Tots in the oven kind of guy then you should probably just buy your ammonium nitrate on amazon.
EDIT:

The solubility is unusual. more than 1:1 at 0C, and 10:1 at 100C.
You might be able to eliminate quite a few other possibilities by checking solubility.

[Edited on 26-10-2016 by Maroboduus]
OneEyedPyro
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You could mix it with some sulfuric acid, you should get HNO3 fumes when you blow on it and if you add some copper wire it will produce NO2 upon heating.

AngelEyes. Obviously anything found in cold packs is going to produce an endothermic reaction when added to water.
Brom
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I suggested using hydrochloric acid because it is the most readily available and cheap of the mineral acids and copper will not produce NO2 with anhydrous HNO3, some water is needed or the copper will form a passivation layer. So if concentrated sulfuric acid is used it must be diluted.
OneEyedPyro
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I think the sulfuric acid stops the passivation effect of the HNO3. It worked for me with 98% sulfuric and dry ammonium nitrate.

[Edited on 27-10-2016 by OneEyedPyro]
AngelEyes
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 Quote: Originally posted by OneEyedPyro AngelEyes. Obviously anything found in cold packs is going to produce an endothermic reaction when added to water.

Yes, of course, not sure what the hell I was thinking...

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Brom
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That is interesting that the sulfuric acid would prevent passivation. I will have to do some experiments with this such as placing copper in anhydrous nitric acid then adding conc. Sulphuric acid and observe what happens.
Brom
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I just mixed some ammonium nitrate with concentrated sulphuric acid and added a piece of copper wire and after 10 minutes at 60 degrees c. no reaction was observed. Upon addition of water NO2 was produced. And i know it is not a good idea to add water to concentrated acids but i was careful.

[Edited on 27-10-2016 by Brom]
OneEyedPyro
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Interesting, when I do it I get a nearly instant reaction. It begins boil and copious amounts of NO2 is generated.
I'm using a wad of fine copper wires from lamp cord rather than one solid piece of copper, I suspect the greater surface area is what's allowing this to happen. I also wonder if my acid is truly 98%.
Brom
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My acid is reagent grade from EMD. I used my pure stuff so i was sure i had no water involved. But i added quite a bit of water before NO2 began to bubble out so i wouldn't think our reagents would be different enough to give different results. Ill give it a try with some copper with a higher surface area.

MineMan
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Just mix it with 50% mg powder and see if it lights, take out the suspense man!
Jimbo Jones
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Magnesium powder is not always available. There is even simpler way. Make some concentrated solution of the suspected AN and soak a sheet of newspaper with it. Dry, roll and light the resulted “smoke bomb”. If the crystals are AN or a mixture with AN, the paper will burn with a lot of smoke.
Maroboduus
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It seems this stuff is probably either Ammonium Nitrate or Urea.

If he just heats a pinch of it on a spoon, shouldn't it make N2O if AN, and NH3 if Urea?

That would be an obvious difference in odor.

And if it doesn't melt fairly quickly it would be some other salt.

NitratedKittens
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 Quote: Originally posted by Maroboduus It seems this stuff is probably either Ammonium Nitrate or Urea. If he just heats a pinch of it on a spoon, shouldn't it make N2O if AN, and NH3 if Urea? That would be an obvious difference in odor. And if it doesn't melt fairly quickly it would be some other salt.

Bad news, i just did this test on what i thought was ammonium nitrate from a cold pack, it was urea

Basket of kittens for you ........BOOM
XeonTheMGPony
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Wall mart cold packs seem to be cal ammonium Nitrate here in Canada still, just add some ammonia to precipitate out the cal, vacuum filter and dry.
CharlieA
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Today I bought "up and up" cold packs from Target. A box of two cold packs cost about $3.50 USD and contained a total of about 250 g of ammonium nitrate (about$7 per pound). I have not yet determined the purity of the ammonium nitrate.
Laboratory of Liptakov
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Here is video, difference between urea and AN on the copper plate , heated simply test. Maybe help it , for you and us. Dr.

Safety explosive Alfred Nobel 1867. Safety ecologic detonator Dr. Liptakov 2015, inventor of CHP
npassbbi
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I've been wondering the same thing about some cold packs I bought from walgreens here in the states. I did some tests tonight, and based on solubility (about 108g/L) and pH of the saturated solution (7, using hydrion paper), it looks like they're urea at this point.
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 Sciencemadness Discussion Board » Special topics » Energetic Materials » Do Walgreens Instant Cold Packs still contain Ammonium Nitrate? Select A Forum Fundamentals   » Chemistry in General   » Organic Chemistry   » Reagents and Apparatus Acquisition   » Beginnings   » Responsible Practices   » Miscellaneous   » The Wiki Special topics   » Technochemistry   » Energetic Materials   » Biochemistry   » Radiochemistry   » Computational Models and Techniques   » Prepublication Non-chemistry   » Forum Matters   » Legal and Societal Issues