Sciencemadness Discussion Board

What is in Walgreen's Instant Cold Packs?

JJay - 28-2-2016 at 14:26

I recently obtained some instant cold packs from Walgreen's. The contents were not listed on the package, but I had read some online sources on other forums stating that they were ammonium nitrate and an unusually pure source of it.

I removed the prills from the pack and found them to be a dirty white color, smelling of ammonia. That's pretty consistent with what many people have reported that ammonium nitrate looks like, but I've also found several reports stating that Walgreen's instant cold packs do not contain ammonium nitrate or that they contain it mixed with other substances.

Several brands that are available locally state that they contain ammonium nitrate on the package (and of course I could just buy it). But does anyone know offhand what is in Walgreen's cold packs?

Amos - 28-2-2016 at 15:56

It's ammonium nitrate. I use them to prepare concentrated ammonia by reacting them with sodium hydroxide. I generally use excess sodium hydroxide in the process, and then treat the finished reaction mixture with dilute nitric acid to make sodium nitrate as a byproduct.

JJay - 28-2-2016 at 16:03

I thought so... I think I'm going to use them to make nitric acid and save my potassium nitrate since it is harder to find.

Now if I can just find some relatively pure urea... I found it locally as an ice melt, but according to the label it is contaminated with propene (??) and a blue copper cyanate pigment that I suspect will be hard to completely remove by recrystalization.

macckone - 28-2-2016 at 16:23

Cold packs are almost universally either ammonium nitrate or urea. Urea can also be found as a component in fertilizer. Ammonium nitrate can as well but it is always contaminated a wide range of 'crud'.

The urea ice melt has a coating on it that is the propene crud. And the blue copper cyanate is dispersed through out. Yes the blue stuff is next to impossible to remove. A good way to remove it MIGHT be to add sodium bicarbonate but that might just be another way to add more unwanted ions to the mixture.

UC235 - 28-2-2016 at 16:42

I have never managed to get rid of the blue dye. It even seems to co-crystallize out from boiling denatured alcohol. Or enough makes it into the crystals to stain them, at least. I bought 5lbs of clean urea from ebay and used the blue stuff as fertilizer.

unfrozen - 28-2-2016 at 18:25

Quote: Originally posted by JJay  

Now if I can just find some relatively pure urea...

Look for "diesel exhaust fluid" at your auto or hardware store. I looked at the MSDS for the fluid at Menards and it says urea and water.
http://www.menards.com/main/tools-hardware/automotive-marine...

cyanureeves - 28-2-2016 at 18:54

http://www.fertilome.com/product.aspx?pid=4417c335-6984-49ad... it is a little bit off white color but when it is recrystallized it makes beautiful shards.

MrHomeScientist - 29-2-2016 at 06:52

I can also confirm Walgreens instant cold packs are ammonium nitrate. I've made both concentrated ammonia and nitric acid from this material, after dissolving in water and filtering off some insoluble impurities (floating crud, probably anti-caking agents). If you check the label these things always (in my experience) say "Contains: ammonium nitrate" or "Contains: Urea". I believe WalMart is in the urea camp, now.

JJay - 29-2-2016 at 08:20

According to Walmart.com, the red Equate brand instant cold packs contain calcium ammonium nitrate. Locally, only the blue Equate brand packs were available a few days ago, and they state that they contain ammonium nitrate. Certain other cold packs on Walmart.com do contain urea but I didn't see any of them on the shelves here (probably sold out), and I don't see the blue packs on Walmart.com. So I think the ingredients in Walmart brand cold packs vary.

Walgreen's is the only brand of cold packs I have found that does not list the contents on the package.

Magpie - 29-2-2016 at 08:30

This may not be practical for some but I bought a 50 lb bag of urea at a weed & feed store for $10 some years ago. I use it mostly as a de-icer on my sidewalks. But when I have needed some for my chemistry it has worked very well. It is mostly pure but I recrystalize it using denatured alcohol before use using the procedure in Prepublication.

Crappy Nitrate IMO

(UH) Stacked - 1-3-2016 at 00:36

size1 The cold packs from whal-Greens suck in my opinion
If you want better nitrate i would suggest going to a Rightous-Aide for *8 packs of instant cold packs. The prills are decent in size and are pure white, ( im guessing its cleaner than that brown moist wal-greens and wally worlds calcium AN crystals.

JJay - 1-3-2016 at 02:25

I ended up getting some urea from eBay. Walgreens has 8 packs of cold packs too. The ammonium nitrate from them looked like it might have some dirt in it, but I am not very concerned about it since I plan to use them simply for making nitric acid.

Quality Check

(UH) Stacked - 1-3-2016 at 14:51

So is the AN better when the prills are actually snow white? or is it "purer" when its that dirty heroin HCl color?

JJay - 2-3-2016 at 00:49

I don't know.... Pure ammonium nitrate should be snow white. But not everything that is snow white is pure ammonium nitrate.