melvinthedestroyer - 6-7-2011 at 13:31
Hello sciencemadness!
I've been browsing this forum for a while now, and I finally decided to make an account! Great information and community! I did a quick search for
long term chemical storage and didn't find any promising threads, so I thought I would request some information...
I am very new to hobby chemistry (although I have been familiar with a good bit chemistry at the university level for some time now) and recently took
several chemicals off the hands of a friend of mine who has had them stored away in a closet.
My questions is: are these chemicals still what the containers say they are after being stored for so long? They have been kept at approximately 20 -
28 deg C for 9+ months now. Some chemicals are a year old. Most haven't been opened. I am curious as to if they are still usable, what undesirable
reactions may have taken place in this time, and (if anyone happens to know) what tests I could perform to determine if they are still viable.
Here are several of the chemicals:
Formic acid, 90% conc. Stored in HDPE bucket, tightly sealed, never opened.
Glacial acetic acid, 99.85% conc. Stored in HDPE bucket, tightly sealed, never opened. I noticed that the metal right around the cap to this bucket
was heavily rusted, and the closet smelled slightly of acetic acid.
Potassium Carbonate, 99%. Stored in a plastic freezer bag, stored in another plastic freezer bag.
DMSO, 99.9%. Stored in original HDPE container, shrink wrapped.
Glycerol, "pure." Stored in original plastic container and tightly wrapped in plastic wrap, never opened. Stored in sawdust.
DCM, "pure." Stored in original plastic container and tightly wrapped in plastic wrap, never opened. Stored in sawdust.
Sulfuric acid, concentrated. Stored in original plastic container and sealed in a plastic bag.
I know he has others that I may acquire, but that's it for now. Thanks for the help!
hkparker - 6-7-2011 at 13:40
wow you beat me to it, I was about to open this thread is a few weeks. Now if I do I'm going to get someone telling me to UTFSE 
. I will be at college and need to store everything, need to know what is a no-no
that I might have thought otherwise ok.
For your question, Everything should be fine. As long as it doesn't decompose (NaClO) or absorb CO2 (NaOH). Sulfuric acid will pull in water if not
store3d tight, but if there isn't a volume increase then your fine.
I'll post my list of questionable chems soon.
bob800 - 6-7-2011 at 14:25
@melvinthedestroyer:
Your sulfuric acid may appear brown/black from carbon particles (from slowly decomposing the plastic), but it shouldn't affect most reactions, as
carbon is quite nonreactive. Also, since glycerol is hygroscopic, it may have absorbed some water from its surroundings. However, I still think its
fine, being sealed and stored in sawdust!
As hkparker said, none of your chems sound like they're horribly unusable. They sound like they've been sealed and stored properly, so I think you
should be fine!
Dre_co - 6-7-2011 at 17:15
I'm looking at getting 5L of 68% HNO3 delivered in a HDPE container. (I know it is not the original, because he's splitting up a drum).
I told him I was concerned about long term storage. And his reply was that since the original drum was HDPE then a 5L HDPE container will be fine. I'm
thinking the drum was HM-HDPE, not the "standard" HDPE.
The results of my googling, say little to no damage after 7days. That seems pretty vague to me. Anybody have any experience storing nitric acid in
HDPE?
I'm looking to store for about 9months while I'm overseas. (I also won't be there to transfer to glass)
hkparker - 6-7-2011 at 18:15
Mine came in HDPE but I didn't trust it, and transferred it to glass the day it got here. Doesn't mean its unsafe though, keep looking around online
I've seen some pretty descriptive stuff about this.
Nitric + HDPE bottle + 1 year ----> No visible damage
bob800 - 6-7-2011 at 19:09
My "70%" nitric acid (though it's probably actually 68%) came in an HDPE bottle as well. I've kept it in there for a full year, and there does not
appear to be any visible damage to the bottle. The acid has also remained crystal clear, so I don't think there's anything wrong with storing nitric
in HDPE bottles. However, it would probably be a good idea to use glass, just to be on the safe side. Don't drop it though
!
woelen - 6-7-2011 at 22:56
Many many chemicals can be stored without problems for years or decades. Most of the chemicals I have are well over 10 years old and some of them are
30+ years old.
Actually, almost all inorganic compounds can be stored indefinitely, provided they are stored in a dark and dry place and in well-sealed containers.
Even hygroscopic ones and easily oxidized ones can be kept without problems if their container is well-sealed. I have 10 year old Na2S, which is very
hygroscopic and also is oxidized very easily, but it looks as when I purchased it and it also reacts as when I puchased it. When I purchased it, it
already was old.
Some chemicals need special containers to keep them well and these are:
- concentrated sulphuric acid: keep in glass container with well sealing screw cap.
- concentrated nitric acid: keep in glass container and use screw cap with teflon inlay.
- concentrated hydrochloric acid: keep in glass container and preferrably use screw cap with teflon infay.
Stuff like Br2, PCl5, SOCl2, SO2Cl2, CH3COCl is VERY corrosive and these ONLY can be kept indefinitely if stored in glass ampoules. I melted all of
these in glass ampoules of 10 ml or 25 ml and I only break one if I need some of these chemicals.
AndersHoveland - 6-7-2011 at 23:15
The fumes from my 70% nitric acid gradually attacked the plastic lid after several years (about five), until it cracked away, despite the liquid never
being in direct contact with the lid. I have no idea how long the glass bottle full of dangerous nitric acid sat on the shelf without a lid. Could
have started a fire if it got tipped over. So to answer your question, 70% nitric acid will attack HDPE after several years. I was told by a college
professor that after every few years they must replace the plastic bottles containing 40% nitric acid. Naturally one would wonder why they sell it in
a container that the acid will eventually eat through. I think the reason is that teflon is more expensive, and glass could break during shipping.
woelen - 7-7-2011 at 01:46
For this reason I repack some of my chemicals after purchase. I also had nitric acid in plastic bottles (not even thickwalled HDPE). Immediately after
receipt of these bottles I put the acid in glass bottles with a sturdy cap which can resist the acid for decades.
The same is true for my bottles of acetic acid and hydrochloric acid. They came in plastic bottles and I repackaged them in bottles like this:
The caps of these bottles are fantastic. No fumes escape the bottle, nothing at all. I also store bromine in such a bottle and 95% fuming nitric acid:
I also prefer storing chemicals in clear glass. Some brands of brown glass leach colored metal ions into the liquid, which is stored in them. If the
stored chemical deteriorates in light, then the bottle is stored in a dark box.
[Edited on 7-7-11 by woelen]
LanthanumK - 7-7-2011 at 02:52
The "CaO" I obtained from a 25 year old chemistry kit is completely CaCO3.
[Edited on 7-7-2011 by LanthanumK]
melvinthedestroyer - 15-7-2011 at 11:57
Thank you all for the quick and informative replies!
So it is my understanding that the sulfuric acid may be tainted with carbon? How can I tell? What would I have to do to test for impurities, and
remove them?
I would perform a "qualitative test" (look at it) myself if I had my lab completely set up. But as of now, it is not, which means I do not have any of
my safety equipment (not even a pair of gloves at the moment) and I am a stickler when it comes to safety. Yes, even with a little drain cleaner.
Thanks again!
bob800 - 15-7-2011 at 12:55
If there is carbon in your sulfuric acid, you can usually tell just by looking at it (it will appear brown/black). However, carbon is not very
reactive and it shouldn't need to be removed.
hkparker - 18-7-2011 at 13:59
What about concentrated ammonia? Its in a glass bottle with a teflon cap, I was going to wrap electrical tape around the top. How long would that be
safe for?
bob800 - 18-7-2011 at 17:49
I would think it would be fine for virtually forever, except it might leak ammonia vapor and slowly lower its concentration. The tape sounds like a
good idea to stop this (around the threads on the bottle), but you might want to check the chemical resistance of electrical tape (teflon plumbing
tape is best).
Mixell - 19-7-2011 at 00:26
Is there any point in storing iodine in the freezer? To lower its sublimation rate.
The iodine is stored in a tightly screwed brown bottle (but I'm afraid its not completely vapor proof) that is inside a resealable plastic bag.
tmb - 19-7-2011 at 03:02
At my company we had a bottle of iodine that was unopened in its original glass bottle within a plastic tub. After several years the tub was opened
and the outside of the bottle was stained brown from the vapors.
I would parafilm the top at least, if I were you. Several bags and freezing can't hurt, but if you can effectively seal the bottle perhaps freezing
(or putting in the freezer, rather) is unnecessary.
Mixell - 19-7-2011 at 04:25
Well, I got room in my freezer, so why not.
hkparker - 19-7-2011 at 12:55
I have never frozen by iodine and its stored alright. Its been kept cool and out of light.
Can anyone say from experience how well ammonia stores?