ahill
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polypropylene caps for conc. H2SO4/HNO3
I keep a bit of conc. H2SO4 and HNO3 around - I am not super happy with my acid bottles (ground glass stoppers wound with PTFE tape), and thought I'd
buy some proper ones.
Westlab, who I have had good experience with in the past, recommended these and these when I asked - the 500/1000ml versions look like just the thing, and the price is OK - but I am a bit concerned about the caps - are these
polypropylene/polystop caps suitable for storing 98% H2SO4 and 68% HNO3 ?
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Chlorine
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Polypropylene won't hold up against nitric acid or sulfuric acid. I'd suggest looking for an amber glass bottle with teflon stopper caps.
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Deathunter88
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Quote: Originally posted by Chlorine  | | Polypropylene won't hold up against nitric acid or sulfuric acid. I'd suggest looking for an amber glass bottle with teflon stopper caps.
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Because sulfuric acid isn't volatile and it isn't in direct contact with the cap, it is fine to store it with a polypropylene cap (or basically any
cap for that matter). Nitric acid will eat through basically any cap except teflon caps. But it takes 5-10 years for this to happen so I wouldn't
worry about it too much. Just change caps every 5 years and you should be fine.
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PeterC
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If you want a secure bottle with a GL45 cap (like the ones in the first Westlab link) all you really need to do is buy a PTFE lined GL45 cap (commonly
red or blue with a red element). http://www.duran-group.com/en/products-solutions/laboratory-...
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ahill
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Thanks for the link Peter - these look like just the thing.
Now I have just got to find someone to sell me some.
I actually bought the clear westlab bottles I linked to. (after they assured me that they would be up to it) - and they _are_ lovely. I left a couple
of drops of 98% H2SO4 on one cap for a few days with no visible effect, and so have pressed them into service - but wouldnt mind replacing / upgrading
them to PTFE lined anyway.
How did you know the caps were GL45 ?
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PeterC
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GL45 is the stereotypical thread found on lab media bottles and if you check the manufacturers catalog (http://helmaus.com.au/wp-content/uploads/2014/10/28tgi_labor...) you'll see that all their bottles have a GL45 thread.
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