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Author: Subject: Boiling Stones?
Fyndium
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[*] posted on 2-9-2020 at 11:04


I indeed posted about this on another topic, but for the record, activated carbon granules have worked for me for everything I've used them so far, from acetone, ethanol, styrene to sulfuric acid. I used them also in vacuum distillation as an accidental impurity, and was glad I did because the bleeder tube was clogged and I had to draw a new head, but the liquid still boiled perfectly smoothly.

ezgif-7-49a7e5d58940.gif - 2.6MB

I have never gotten acetone bump on me before, but it did happen. Apparently too clean glassware and distilled and filtered acetone solution was too pure for any nucleation to occur.

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wg48temp9
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[*] posted on 2-9-2020 at 12:39


If you want to know how good your boiling stones are let the flask or beaker boil vigorously for a few minutes then let it cool until all the boiling stops for a few minutes then reheat the flask slowly. Porous boiling stones not flooded with the liquid will stop bumping as before but plain glass and smooth glass balls probably will not.

The porous boiling stones when they contain air act like lots of small capillary tubes releasing small bubbles of gas that prevent bumping much more efficiently then any smooth glass.




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Sulaiman
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[*] posted on 2-9-2020 at 16:42


I have recently been doing a lot of EtOH distillations and for boiling stones I have been using these

stones.jpg - 136kB

STONES, from the garden - they work really well giving a stable rolling boil.

Borosilicate glass is harder than Marble and so far no signs of scratching




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pneumatician
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[*] posted on 3-9-2020 at 07:12


I distil a lot of wine & EtOH and NEVER put anything in the flask, no bumping. You put too much heat power???? Use allways the lower heat necessary, you will save yourself a lot of trouble.
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Sulaiman
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[*] posted on 3-9-2020 at 14:57


Quote: Originally posted by pneumatician  
I distil a lot of wine & EtOH and NEVER put anything in the flask, no bumping.

I guess that you are doing simple distillations only, with no fractionating column?
(or possibly a poor fractionating column such as a Vigreux)




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[*] posted on 3-9-2020 at 16:47


Quote: Originally posted by Sulaiman  
Quote: Originally posted by pneumatician  
I distil a lot of wine & EtOH and NEVER put anything in the flask, no bumping.

I guess that you are doing simple distillations only, with no fractionating column?
(or possibly a poor fractionating column such as a Vigreux)


I use in second and + distil a Vigreux of 30cm.

this guy say: from 40% to 95% EtOH in a step.

https://vimeo.com/170121935

[Edited on 4-9-2020 by pneumatician]
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Sulaiman
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[*] posted on 4-9-2020 at 06:10


Quote: Originally posted by pneumatician  

this guy say: from 40% to 95% EtOH in a step.

I seriously doubt that he got 95% from 40% with that configuration.




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[*] posted on 4-9-2020 at 06:31


Quote: Originally posted by Sulaiman  
Quote: Originally posted by pneumatician  

this guy say: from 40% to 95% EtOH in a step.

I seriously doubt that he got 95% from 40% with that configuration.


me too, :-) however next time i will try to see how that is
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[*] posted on 17-9-2020 at 14:16


https://www.sciencemadness.org/whisper/viewthread.php?tid=64...
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Fyndium
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[*] posted on 6-3-2021 at 06:34


It took me a while to realize that the boiling chip element is absolutely crucial for efficient and smooth boiling for pretty much any liquid. Sometimes I got bumping so hard it effectively prevented distillation, including vacuum. The take-off rate seems to be also much higher, and even using small equipment a steady stream of liquid can be condensed, instead of drops. I've distilled 240C boiling liquids under vacuum with stream-takeoff rate.

Activated carbon.

That's the magic stuff. It pretty much always works. A teaspoon of granules in any liquid will make it go very smooth, producing an intense curtain of bubbles. A fresh load is required for every batch, including if the liquid is cooled down, as it seems that the carbon absorbs liquid and stops working.

Under no circumstances can carbon added to hot or boiling liquid. It will flash boil and blow out of the vessel. Always add it to cold liquid.

It is likely that any activated carbon will work as well. These are from brewing shop, size 2-3mm granules if I remember right.

Distillation of 110C boiling liquid:

ezgif-2-afbccba9deb6.gif - 6.7MB

Vacuum distillation of 240C boiling liquid:

ezgif-7-039829c890a3.gif - 7.2MB

[Edited on 6-3-2021 by Fyndium]
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