quicksilver
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unique issue re: Glacial Acetic Acid
I have had never seen this previously.
Quick question here: I have a sealed bottle (factory sealed) of Glacial acetic acid that has become crystalized. Not exposed to extremes in temp or
UV. I have not seen this before, nor do I believe there are any contaminents to account for this. I checked Merck, searched around on the net - found
nothing regarding this behaviour in this chemical. Has anyone ever seen Glacial acetic acid solidify?
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Mumbles
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It does freeze at 16.7C. Is it below or near this temperature? At this time of year being stored in a garage, or shed, perhaps even basement, could
have the temperature drop below this freezing point of GAA. That is the only thing I can think of. I have seen reference for dimerisation, but
never heard of it taking place in liquid, only gas phase. I suppose since it is very water-free, dimerisation could take place easier. Water
quenches the dimerisation very fast. In addition, I don't know of any properties such as melting point of the dimerized form.
Does it look like frozen GAA? Well, that is if you have ever seen it.
[edit] well, I suppose it is probably a brown bottle, so it could be hard to tell.
[Edited on 11-28-2005 by Mumbles]
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Darkblade48
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From an MSDS, I found that the melting/freezing point is 16.6 C. So, if you're storing the glacial in a cool basement for a long time, it might
result in the freezing of the glacial.
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quicksilver
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This is why it has been driving me crazy...it's stored in 20C ! The bottle is clear .... We are talking sealed...really sealed. I even put it in
my little computer room and am looking at it right now. Looks like a broken glass cylinder in the bottle; a huge crystal. I have another little pint
bottle (this is a gallon, I am talking about) and it has remained in a liquid state.
The 1st thing I did was check the FP temp and - no luck, I'm fine there.
But that is a good point, the freezing point temp is high....many homes do get to 60 degrees F this time of year. But yet certainly if such a thing
occured, would it not melt as many other fluids do once 16 C + were reached?
I apprieciate you all taking the time with this little puzzel; I have yet to have had such a thing happen and not know why.
Basically I put a cap on my little mystery. It simply had to drop in temp at one time (I would now question the 16 C and say it may actually be even
warmer!) and continues to maintain it's cold solid condition; unique in that manner. It would make a great "cold-pack" for an injury
 As some thermic reactions continue, this one does as well. It will simply
refuse to give up it's temp. - quite interesting really; here you have an acid that will maintain a cold condition. Great for controling
reactions requiring such a thing!
[Edited on 30-11-2005 by quicksilver]
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