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Chemistry Forums for Students => Organic Chemistry Forum => Topic started by: lukas.stib on May 29, 2022, 05:40:45 AM

Title: How big I should use cooking stones and how much?
Post by: lukas.stib on May 29, 2022, 05:40:45 AM

Hello chemists,

I have a problem with boiling stones during fractional distillation. I distill ethanol from the drink I bought, and when I used a stirrer and cooking stones with it, it exploded very hard, "shooting". I had to stop the distillation because the flask also moved on the hot plate. It crashed a lot from a place where there was a large cluster of small stones 1 mm or smaller in size, and among them were larger pieces. I threw away the stones and used a stirrer. Unfortunately the boiling is smaller and I have to raise the temperature. How big should I use cooking stones and how much?

Thank you very much. Lukáš S.

Title: Re: How big I should use cooking stones and how much?
Post by: MOTOBALL on June 02, 2022, 09:08:05 AM

These are called “boiling chips”, and usually only 2 are needed.
Buy proper boiling chips from any laboratory supplier.

You do not use a stirrer when doing a distillation.

CAUTION If you start a distillation and the boiling chips start their off-gassing, if you have to stop the distillation you should allow the solution to cool down to room temperature then add 2 more boiling chips because the original 2 will have absorbed liquid and will not work properly.

Good Luck!

Title: Re: How big I should use cooking stones and how much?
Post by: lukas.stib on June 03, 2022, 09:11:17 AM

OK, thank you very much!  ;)