Muriatic Acid - sealed, in a bag, in a steel drawer - looks like rust under the bag!?

THE BACKGROUND:
In my shop I use a lateral file cabinet to keep my 'stuff in bottles and cans'
One drawer is adhesives (3M 77, hot melt sticks, Titebond, extra CA bottle tips, etc.)
One drawer is lubes (WD40, motor oil, grease, etc)
The third drawer is SOLVENTS (Acetone, lacquer thinner, MEK, naphtha, etc.)

I keep my 1 qt. plastic bottle of muriatic acid in that drawer, in a .006" thick polyethylene bag, with a twist-tie on the bag.
Not sure if it 14.5% or 29% (Mr. Lazy Pig Butt doesn't want to walk back out to shop to look)

THE EVIDENCE:
Under the poly bag there is 'rust', or at least it is orangish and slightly wet.
And, INSIDE the bag it is slightly wet and 'rusty'.

The paint on the drawer bottom right under the MA bottle is gone, and when I wiped the 'rust' off that area the paint is stripped and the steel is bare metal clean.

WHAT THE ****??

The plastic bottle is the original bottle, it's been opened a few times for use (like today, getting ugly mineral stains out of our toilet), then TIGHTLY capped - and kept in the poly bag, in the closed drawer, in the shop.

QUESTIONS:
What is going on here?
Why the rust? (OK... acid, I get it - but HOW?)
What is the 'wet'?

Is MA hydrophilic?
Can it propagate through a poly bag and original bottle (I assume it is polyethylene, PEEK, etc. layers)

Any chemists out there?

I'd ask my dad who was a research organic chemist, but he died 6 years ago, so that avenue is closed.

Any thoughts?

Thank you!

Muriatic acid is volatile-ish (HCl is a gas, after all), and will certainly do the things you're describing, especially if it's in an un-cooled area in the summer. Under humid conditions you'll see the 'wet' you're talking about, because as a gas it is hydrophilic.

Why the 'rust' inside the bag is another question, but any kind of steel or iron that gets in there will cause that. It doesn't have to be more than a bit of steel wool or swarf.

in the (climate controlled) chem lab we would store it in glass bottles with tightly fitting caps with teflon liners, and we'd still end up with rusty acid cabinets.

Personally I'd be leery of keeping acids of any kind in a cabinet with solvents....way too much opportunity for , ahem, unintended reactions; were your dad alive, he'd probably regale you with all the exciting ways it could go wrong.

Bruce,
Thanks, I'll keep it under my bed from now on.
:-)

Nah - I'll stick it out in my storage shed near the Nitric and Sulfuric acids.
True story - they're in glass screw-top acid bottles, in a styrofoam fitted container for shipping which is held closed by a bungee and labeled threateningly.

Amazing things can get through plastic, some chemo drugs can go through Nitrile gloves in minutes. And, of course, Indian Meal Moths were found able to eat and digest polyethylene...at least enough to get through bags. I've seen that last one happen myself.

Your plastic bag is porous. Used to leak check machines and found a pile of things that leak that you wouldnt expect. We used helium to leak check.

The shelving at the home supply where muriatic acid is kept, look at the steel shelves, if the acid has been stored there, they are all rusty.
Metalworking forums talk about where a bottle left in a machine shop caused all the tables and ways to develop a rust film. I store mine outside, I place the original plastic bottle into a 5 gallon dry wall mud bucket, and snap the lid on tight.
Glass storage may help, but the threaded cap will not seal perfect, and you know a metal lid will soon be open air.

The porosity of plastics is a major issue in my work with 'interesting' gases and liquids, the bottle is porous and the bag too, glass bottles are the only way to maintain purity and even then some acids will eat through them, HF especially. Some of our short delivery lines are PFA inside a purged with dry nitrogen PFA over jacket, just to keep the water out, as we aim for a dew point of -120°C or PPB, longer lines are 316L, often overjacketed for safety.

Where I worked eons ago they switched to plastic coated glass after someone picked up two gallons of HCl at the same time and banged them together. The resulting spill cleared the building and resulted in a huge legal case... When the lady who caused the spill woke up in the hospital she found out a male (horrors!) worker carried her into the emergency shower and tore the acid soaked clothing off her. She accused him of attempted rape.

I think "thank you" would be more appropriate.

-Isn't just chemistry sooo exciting?

Some recommended reading is John D Clark's "Ignition!", actually with a preface of Isaac Asimov (sic!)
Subtitle: "An Informal History of Liquid Rocket Propellants":

https://library.sciencemadness.org/l...s/ignition.pdf



Clips from p 89f (of 233) of this "unputdownable" biography, from the "days at the office" of pioneering US rocket scientists.

Attachment 31853 Attachment 31854

French Lab precautionary film: -What the stuff does to your PPE: clean, wet or dirty:

https://www.youtube.com/watch?v=M4l56AfUTnQ

There's a long series of posts by Derek Lowe on Sciencemag.com called "Things I won't work with", like this gem

https://blogs.sciencemag.org/pipelin...gen_difluoride

The heater was warmed to approximately 700C. The heater block glowed a dull red color, observable with room lights turned off. The ballast tank was filled to 300 torr with oxygen, and fluorine was added until the total pressure was 901 torr. . . (atmopheric pressue is 760 torr, for those of you not in the know, so this is a pressurized container at 700C filled with fluorine and oxygen :headshake:

This is really exciting chemistry.

The whole list is here https://blogs.sciencemag.org/pipelin...wont-work-with

Mostly it's things that go BOOM if you look at them weirdly, but some of 'em will dissolve you first THEN go boom...

Every once In a while I read some of 'em just to remind myself just how much safer it is doing IT versus chemistry :-)

I recently listened to these books (I'm an audiobook junkie). The two by Sam Kean are excellent. Liquid Rules is pretty good. All three talk about the dangers of chemical interaction even with solids. If I didn't already have a fascination and respect for chemistry before these, I would after.

Liquid Rules: The Delightful and Dangerous Substances That Flow Through Our Lives by Mark Miodownik

The Disappearing Spoon: And Other True Tales of Madness, Love, and the History of the World from the Periodic Table of the Elements by Sam Kean

Caesar's Last Breath: Decoding the Secrets of the Air Around Us by Sam Kean

Neil

Back when my dad had his chemical company in Boulder, Colorado, there was a release of chlorine gas from a process and it vented outside - right over the Putt-Putt Golf course next door! Yeah, the same stuff chemical weapons use.

Dad ran out to the factory floor to help contain the rest of the mess, and his brother raced off to the emergency room and handed out business cards to the families who came in to seek care, telling them they would cover all costs.

Ah! The good old days of actually being responsible for your mistakes (though, having the vent tube point towards the Putt-Putt was probably not the best decision to begin with!)

Thanks for the suggestions on the books - I read voraciously and continually. I'll get 'em from the library and read 'em.

I like the short 'threatening film' - I gotta get some of that stuff!

I've been reading Helen Czerski's book "Storm in a Teacup" about the physics of everyday things. Really good! Her description of surface tension is fantastic.

MBTW: LIquid helium is weird stuff. Its a superfluid and will simply leak through glass and drip out the bottom of a flask. Now, you have to get it down to 2.71 degrees KELVIN (which is minus -454.792 degrees fahrenheit). Here's a youtube video about that:
https://www.youtube.com/watch?v=9FudzqfpLLs

Oh, and here's a SciAM article about liquid helium

Quote:

---

Originally Posted by jdurand

When the lady who caused the spill woke up in the hospital she found out a male (horrors!) worker carried her into the emergency shower and tore the acid soaked clothing off her. She accused him of attempted rape.

I think "thank you" would be more appropriate.

---

As a first responder that's one of the many issues we have to deal with, these days any suspicion of a female being an adherent to certain religions is enough reason not to touch or treat, lest a male guardian seeks to avenge the loss of family honour. One female student who was treated by a male first responder was honour killed when she returned home, religion of peace my arse.

Today in this country I would be vary wary about helping ANYBODY. Of course I'm in California , one of the places you can get beat bloody with a "LOVE" sign.

I'm also careful of who I talk to and what I say.

Maybe I failed to follow this thread very close but! OOPS! I think I'll keep my mouth shut.

I know I'm a bit late to the party, but being an actual chemist I feel like I should chime in.

As others have said, HCl solutions are rather volatile, especially so if kept somewhere it gets warm. Stock acid bottles come with Teflon-lined caps, but these are mainly to prevent liquid leaks and the interface between the liner and the rim of the bottle is the major route for leakage of HCl vapor. The flexible polyethylene bag acts as a bit of a barrier, but it too is porous and cannot withstand any lengthy exposure to strong mineral acids.

What likely happened is that over time (and probably aided by temperature cycling), you start to build up HCl and water vapor inside the bag, which condenses and runs down to the bottom. It can then permeate through the bottom of the bag, soften the paint, and begin to dissolve the steel of your cabinet. The liquid now contains ferrous chloride, which can permeate back through the polyethylene bag -- this is how you could end up with rust-colored liquid inside the bag, though it should be limited to the bottom where it was in contact with the drawer.

As for safe storage, the ideal situation is a polyethylene- or polypropylene-lined cabinet with built-in ventilation. Most labs I've worked in had the acid cabinets built into the fume hoods, with an air path that would draw air through the cabinet and up into the fume hood. Barring that, it's always a good idea to keep acid bottles in thick polyethylene/polypropylene secondary containers of a large enough volume to keep everything contained in the unlikely event that the bottles rupture. We used polypropylene trays and polyethylene dishes in my lab.

As for segregation, no mineral acid should be stored in the same container (cabinet) as combustible/flammable materials, as this can lead to some very nasty reactions. Furthermore, you should take care to segregate your oxidizing acids (nitric and sulfuric) from both each other and from the HCl. In our lab we only had one acid cabinet, so the nitric and sulfuric acids each had their own thick plastic dishes to keep anything from mixing if the bottles broke. Nitric and HCl form aqua regia when mixed in the right proportion, which can dissolve gold and will produce extremely toxic nitrogen dioxide gas. Mixing nitric and sulfuric is an even worse idea, as it is capable of nitrating almost any organic material (wood, plastic, etc.) and the results tend to be explosive. Granted, these mixtures require very concentrated acids [37% HCl (12 M), 70% nitric (16 M), and 96% sulfuric (18 M)], but why risk anything?

Where I used to work I kept having to harass people about storing random bottles of acids, bases, solvents, etc. IN the emergency showers. But they're a handy storage place!

I also reported one shower that had a PVC pipe coming out one wall and going into the other right at hand-holding height. The pipe carried waste cyanide mixtures. It seemed to me to be unwise having that there.

It's so much fun having an office under an industrial chemistry area, my boss arrived one day to find something dripping from the ceiling through a hole in his desk to the floor. The hole was new.

I was also sitting at my desk one day and saw people run by (our work area door had a window in it) with Scott air packs on. I suggested to my assistant that we take a break outside for a while, at least until whatever it was got cleaned up.

Oh, ****.
I'm glad I learned this by reading, not by direct experience.
:-)

T H A N K Y O U !

I will segregate and put 'em in trays.

Again, thank you!