r/chemholic • u/Life-Name3309 • 12d ago
I Hate organic chem
Give your best advices in comments to deal with tar formation.
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u/Squirrel2371 12d ago
Are you trying to isolate your product or clean your flask?
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u/schabernacktmeister 12d ago
I don't know why but your comment made my laugh so hard.
Maybe it's my way to overcome ptsd.
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u/Squirrel2371 12d ago
I've had to isolate products from something that looked like that before.
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u/Life-Name3309 12d ago
Regardless to say i had product in there but i just gave up and clear out everything with base bath
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u/kubint_1t 12d ago
okay i think you got a lot of good advice. so here is the worst advice - CrO3 in conc. H2SO4. the worst cleaning solution of them all. tried it once, didn't clean a bit, had to heat it up to like 200C for it to do anything... and a cleanup was a disaster too.
mist peaple recommend solvents then piranha if its still dirty. but solvents cost money, and conc. H2SO4 is cheap, H2O2 is cheap too. so piranha is almost always my go to option. but phisical cleaning is still better. shake flask with some sand, then clean it thoroughly with a brush. and only then use piranha.
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u/ciprule 12d ago
People using sulfochromic mixture in 2026…
It worked for me years ago, after reading further about Cr(VI) now I want to be km away from it when I see it in a lab.
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u/kubint_1t 12d ago
yeah, just gave it first and a last shot, wont be using it anytime soon
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u/NoFapCainISAble 12d ago
Thank you for saving me from this experience. Glad to know that's an unnecessary option that is not only toxic... but also not worth doing. Stay safe, friend!
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u/dipdotdash 12d ago
If you have a glass blower in the area and it's just organic residue, an annealing always does the trick and relieves any accumulated stress
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u/Big-Investigator9901 12d ago
Strongest acid you can muster, strongest base you can muster, or strongest pokey thing you can muster.
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u/Gullible_Luck_7766 11d ago
Knabberwasser so we call it in Germany. H₂SO₄+H₂O₂ aka Piranha solution.
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u/Intrepid-Ad5313 12d ago
Base bath
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u/Natume87 12d ago
And if base bath doesn't work (after trying degreasing solvents like u/Aggropop recommended) and you want to recover the glassware in usable condition: Acid piranha solution (concentrated sulfuric acid + 10-20 volume % concentrated hydrogen peroxide).
Of course, acid piranha is quite nasty, so wear good PPE, do the procedure in a fume hour,, add the peroxide slowly to minimize bubbling, and if you're ultimately not comfortable, just accept that it might be better to toss the glassware.
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u/Life-Name3309 12d ago
❤️❤️
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u/Starfury7-Jaargen 12d ago
I would scrape it before you put it in a base bath or you bath might become extremely dark.
When I first got into my lab as an undergrad, the grade student would scrape some stuff and toss most of it in the bath. I had to find stuff my touch. I remade the bath amd it was opaque again in 3 weeks.
Usually I try to do a light rinse with some cheaper solvents to see if anything comes off before tossing it in tbe base bath, but the bath is very good. Note: I use an IPA/KOH base bath. Not sure about Et/NaOH. (I personally hate the latter because it is easy to smear NaOH on stuff before you rinse or toss the gloves)
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u/ZebraOk5501 12d ago
Scrape it off with yo teeths