Schleimsäure
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Gluey mess won't quit in the flask
So I decided to work up my methylated spirit a bit, because as it is the smell is a pain. It's not the cheapest, 2,5 l from S3, a chemical supllier.
It's 99%, denatured with 1% MEK and a few ppm of denatonium benzoate.
Firstly I put 600ml in a 1l flask and refluxed with 10g of NaOH for 3 hours or so. It went from clear to light orange.
Then, after simple destillation the destillate was clear and smelled a lot less then the original product, almost absolute alcohol. So success.
Anyway, I decided to do that with the rest and just built up my 4l 3-neck flask with 1,9l methylated spirit and 31g of NaOH for reflux in a water
bath.
Problem is, the 1l-flask of the first run has a very gluey mass on the ground. Could it be that hot NaOH melted even with the glass?
I put in some chromo sulfuric acid and a short neutralisation took place, after a few minutes most of it is still solid.
I will wait a little longer for the chromo sulfuric to work, but I'm a little afraid I could ruin my 4l 3 neck flask.
Thanks for consideration.
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Chemosynthesis
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What does the "gluey mass" look like? White? Might very well be sodium silicate. Next time, you may wish to seal your glassware better. As for
cleaning, a cool/cold base bath overnight shouldn't show any visibly appreciable etching on non-analytical equipment, however if you are really
concerned about chromic acid etching (as per Can J. Chem. (1962) Vol .40 p), you might look into just using sulfuric acid and/or getting an ultrasonic
cleaner.
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Schleimsäure
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All clear. The whole clump just got off after some pushing with a glas rod. Chromo sulfuric acid is the best
I highly recommend on this method for working up stinky methylated spirit. The end product is not 100% ketone free, but the method is cheap and easy.
The result satisfying for use of cleaning and even as a "better" solvent.
For best results hydroxylamine is needed, which is more expensive and for some hard to aquire.
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Schleimsäure
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Quote: Originally posted by Chemosynthesis  | | What does the "gluey mass" look like? White? Might very well be sodium silicate. Next time, you may wish to seal your glassware better. As for
cleaning, a cool/cold base bath overnight shouldn't show any visibly appreciable etching on non-analytical equipment, however if you are really
concerned about chromic acid etching (as per Can J. Chem. (1962) Vol .40 p), you might look into just using sulfuric acid and/or getting an ultrasonic
cleaner. |
Actually it's kind of orange with clear chrystal like on the borders. And stinks abnormally. But now with the chromo sulfuric acid it has finally
detached from the bottom
I was not concerned about chromic acid etching, but rather about hot NaOH as the rest of the boiling NaOH/EtOH solution.
Excuse my ignorance, what do you mean by sealing the glasware better in that context?
[Edited on 25-4-2015 by Schleimsäure]
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Lambda-Eyde
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MEK, like acetone, will polymerize and make bad smelling, sticky and annoying compounds when exposed to a strong base over time. I'd try to pour in
some gasoline (or equivalent) and leave it on the magnetic stirrer for a while.
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Schleimsäure
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Thank you! So I don't necessarily have to use Chromic acid then.
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Chemosynthesis
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Oh, I misunderstood. I though you had a gluey mass on the ground glass joint area.
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