Author Topic: Formic Acid + Mol sieves = WTF!  (Read 101 times)

antibody2

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Formic Acid + Mol sieves = WTF!
« on: August 30, 2011, 08:25:01 PM »
After spending the better part of last weekend preparing a fresh batch of formic acid Ab2 took a density reading which indicated that it was only about 30-40% formic acid. No problem, Ab2 thinks, she has this whole bucket of 3A seives she has been saving for just such an eventuallty.

This is where Ab2 kicks herself. Rather than testing a small amount she takes several kgs of seives and dumps them into the flask of aqueous formic. The first clue that things were going awry was how hot the flask became, too hot to hold without gloves. FuCK fuck fuck! Oh well too late now she thinks, hoping the heat is somehow being caused by the sudden dehydration. Half an hour later she goes to have a look and the entire flask has crystallized into a solid mass! Still hot.

It was almost impossible to empty the flask. I felt like throwing the flask against the wall. And I think the seives are now useless.

So Ab2 isn't sure exactly what happened, but assumes the formic acid reacted with whatever the sieves are made of to yield some form of formate salt. Ab2 had been under the impression that the sieves were supposed to be inert, lol, NOT!

sigh . . . . :-\

Tsathoggua

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Re: Formic Acid + Mol sieves = WTF!
« Reply #1 on: August 30, 2011, 08:33:24 PM »
Just as well there wasn't an unpredicted dehydration to CO.

THAT would have been a whole damn sight worse than a ruined flask. And it wouldn't have been you that had to see the damn sight worse....
Nomen mihi Legio est, quia multi sumus

I'm hyperbolic, hypergolic, viral, chiral. So motherfucking twisted my laevo is on the right side.

salat

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Re: Formic Acid + Mol sieves = WTF!
« Reply #2 on: August 31, 2011, 01:00:13 PM »
I doubt anything is inert with everything, there are different sieves for different stuff, I usually go look things up to see which one goes with which chemical. 

http://www.erowid.org/archive/rhodium/chemistry/equipment/dryingagent.html

I didn't know formic acid was so volatile.  Read this over at SciMadness

http://www.erowid.org/archive/rhodium/chemistry/equipment/dryingagent.html

Salat
Salat

antibody2

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Re: Formic Acid + Mol sieves = WTF!
« Reply #3 on: August 31, 2011, 02:08:12 PM »
Thanks Salat ;)
The 2nd link was the same as the 1st.

Boric anhydride . . !!? The tangled webs we weave ourselves into with this hobby . . .

letters

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Re: Formic Acid + Mol sieves = WTF!
« Reply #4 on: September 01, 2011, 04:33:49 PM »
mol sieves ARE basic, you can read this in many places, including the MSDS usually. this is why you should not use them to dry acetone (promotes self condensation) and most surely should not be used to dry acids.