Sodium Hydroxide storage

Anon Ymous · Aug 31, 2017

Hello everybody...

The title is quite descriptive I guess. I have some NaOH that came in a heat sealed plastic bag. I know that it's a highly hygroscopic compound and do my best to keep it as dry as it came. I've transferred some of it in other plastic bags that I heat seal, but it's all very impractical. So, do you have any tips? How do you store yours? This thing is very caustic, so is there some kind of preferred container for it?

Thanks in advance

Martin Rickards · Aug 31, 2017

Dissolve it in a known amount of water, store it in an airtight plastic bottle and use it as needed. You've probably turned some of it to carbonate already transferring it to bags, but not enough to make any practical difference.

trendland · Aug 31, 2017

Anon Ymous said:
Hello everybody...

The title is quite descriptive I guess. I have some NaOH that came in a heat sealed plastic bag. I know that it's a highly hygroscopic compound and do my best to keep it as dry as it came. I've transferred some of it in other plastic bags that I heat seal, but it's all very impractical. So, do you have any tips? How do you store yours? This thing is very caustic, so is there some kind of preferred container for it?

Thanks in advance

Looking to storage materials in general we only will find 3 groups : Glaas,plastic,metal !
We all agree Witz that containers from wood will not help.!
What is the best? I personaly would awoid metal to all chemicals.
There are a kind of possible interactions/reactions with metal - as you might know for sure.
PLASTIC is the best I would like to say -
the question is what kind of plastic types.
Have a look to the original chemical containers from chemical supliers.
In regard of higroscopic issues the plastic container you need have to be
100% airtight - yes you know this, but most cases with srew cap can't guarrantee this - the are airtight to 94%.
That's the first key to your problem.
So far - so good. The next key is relative air humidity inside the container.You can
control this a bit due to temperatures wile filling it.
But this isn't enougt.
Sorry to say Anon Ymous but from my point a vacoum is the best - therefore your heat sealed plastic bag might be the
best in case there you have a vacoum.
Is this not so your chance might be a kitchen vacoumizer.

with regards

nmp · Aug 31, 2017

That reminds me. I got a lb of it as lye. It is in the worst form possible - tiny fluffy particles like ground-up styrofoam. Not good to handle and I am sure not good in storage re: moisture. Martin's idea of making a solution makes sense. The best non-glass material to store the solution would be polypropylene. That's how you will get it from Sigma-Aldrich. HDPE might work too.

Gerald C Koch · Aug 31, 2017

Sodium hydroxide will readily absorb both moisture and carbon dioxide. Plastic bags are not suitable for its storage. Transfer it to a screw cap container (preferably glass) ass soon as possible. Polyethylene or polypropylene jars are OK IF the cap is also not made of the same material. Soft plastic on soft plastic does not make a good seal. When transferring chemicals I use canning jars. They are sheap, available in several sizes and generally available.

avb · Sep 1, 2017

NaOH should not be stored in glass since it etches glass. When you buy pellets they come in plastic containers. And solutions do as well.
I've kept them stored in the plastic container they come in.

mshchem · Sep 1, 2017

Put it in a heavy Ziploc bag then stuff that into a wide mouth bottle. I used to buy it in bulk, plastic bag inside a corrugated box, 25lb at a time. Keeping it dry is the key. It will last for years

tokam · Sep 1, 2017

I wouldn't recommend plastic containers made of PET. A few years ago a friend gave me a half filled PET jar with plastic lid. I put it on a shelf and when I revisited it after about six months the bottom of the jar had disappeared and the NaOH was spilled on the shelf. Needless to say it was a very careful exercise to clean up the spill. The shelf which was stained and varnished also needed rework as the NaOH, of course, had stripped the finish from the timber.

Anon Ymous · Sep 1, 2017

Thanks everyone

It seems that a combination of a wide mouth glass jar and a heavy plastic bag would do the trick.

KPA40 · Sep 1, 2017

I bought some NaOH in 2011 from a private person. He shipped it a little bit dangeroues in two ziploc bags in an air bubble mailer. Since then, I store it in a clear wide nack bottle made for chemical purposes.
It is filled up to 2/3. There are absolutely no signs of etching at the bottle and the NaOH shows no sign of moisture.

Gerald C Koch · Sep 1, 2017

avb said:
NaOH should not be stored in glass since it etches glass. When you buy pellets they come in plastic containers. And solutions do as well.
I've kept them stored in the plastic container they come in.

Gerald C Koch · Sep 1, 2017

avb said:
NaOH should not be stored in glass since it etches glass. When you buy pellets they come in plastic containers. And solutions do as well.
I've kept them stored in the plastic container they come in.

I have bought sodium hydroxide dozens of times sometimes it comes in a plastic container and sometimes in glass. The reagent grade has always been in glass. So it can etch the glass - who cares. This effect is very small and the chemical is still good. For the consumer iit is important that the chemical not absorb water or carbon dioxide.

Martin Rickards · Sep 2, 2017

When I was selling laboratory chemicals worldwide, sodium hydroxide, both analytical and reagent grade, were always sold in PE bottles. The only time it was shipped in glass containers was a N1 and 0.1 N volumetric solutions. Volumetric concentrates were in PE ampoules.

Sodium Hydroxide storage

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