Sciencemadness Discussion Board

First attempt at a distillation

SnailsAttack - 15-2-2022 at 02:54

https://www.youtube.com/watch?v=TjlR6Qtr6LU

a video of my first attempt at a distillation where I managed to superheat the flask. it flashed to steam, ejected the condensor, and fireballed spraying 40% isopropanol and green food coloring all over my room

it was a formative experience

Rainwater - 15-2-2022 at 03:38

Fire safety protocols must be in place. When heating, like most other aspects in chemistry, surface areas increase's reactivity.
Instead of heating just the bottom of the tube. Tilt it and heat it up the sides.
Controlled heating would help.
It looks like you experienced bumping. Or a bump at least.
Tips)
1) Try adding a non reactive material(boiling stone) to the bottom of your apparatus. Something insoluble in your solution. It will act as a neculation site for vapor to form.
Stiring is the best method I have found. But not always practical.
2) make sure you minimize restrictions in the vapor path.
If your flow path is 1 liter a minute and your vapor production is 2 liters a minute you will build up pressure.
This can lead to runaway (example in your video). As pressure builds. The boiling point increases. Temperature increases. Repeat.
When the pressure is reduced( plug poped off) the boiling point is reduced. When the fluid is at a greater temp then the boiling point it flash boils.

Sulaiman - 15-2-2022 at 06:53

Ah! I see that you are using the accelerated learning technique,
best way to learn,
if you survive unharmed ;)

dawt - 15-2-2022 at 09:12

It looks like you corked the receiving flask? In that case you applied heat to a closed system, and the pressure built up until your apparatus rapidly self-dissassembled.

Texium - 15-2-2022 at 09:49

This is why it’s recommended that you do your first distillation on something not flammable… my first was bromine, which, while not flammable, I still wouldn’t recommend for obvious reasons. :P

Distilling water isn’t too fun but it’s good practice to make sure your apparatus is safe and your technique is sound.

Herr Haber - 15-2-2022 at 12:09

Quote: Originally posted by Sulaiman  
Ah! I see that you are using the accelerated learning technique,
best way to learn,
if you survive unharmed ;)


Good one ! :)
I thought that I could have done this myself when I was younger.

Looking at the video it also looks like a closed circuit. Is it a bump or overpressure ?

SnailsAttack - 15-2-2022 at 12:49

Quote: Originally posted by Rainwater  
Fire safety protocols must be in place.

I had a bottle of water at the ready and moved everything flammable out of the way. I was prepared for everything except the liquid's desire for liberation.
Quote: Originally posted by Rainwater  
Instead of heating just the bottom of the tube. Tilt it and heat it up the sides.

Will try this next time.
Quote: Originally posted by Rainwater  
Try adding a non reactive material(boiling stone) to the bottom of your apparatus. Something insoluble in your solution. It will act as a neculation site for vapor to form.

I dumped some sand in the test tube on my next attempt. Fixed the problem immediately.
Quote: Originally posted by Rainwater  
When the pressure is reduced( plug poped off) the boiling point is reduced. When the fluid is at a greater temp then the boiling point it flash boils.

Ah. yeah that'd definitely exacerbate it.
Quote: Originally posted by Sulaiman  
Ah! I see that you are using the accelerated learning technique,
best way to learn,
if you survive unharmed ;)

absolutely
Quote: Originally posted by dawt  
It looks like you corked the receiving flask? In that case you applied heat to a closed system, and the pressure built up until your apparatus rapidly self-dissassembled.

The cork was not secured. Because the receiving flask was designed to double as a condensor (test tube sitting in a glass of icewater) I wanted to slow the escape of vapors as much as possible to give them time to condense.
Quote: Originally posted by Texium  
This is why it’s recommended that you do your first distillation on something not flammable

originally I was gonna distill 99% acetone!
Quote: Originally posted by Texium  
Distilling water isn’t too fun but it’s good practice to make sure your apparatus is safe and your technique is sound.

yeah, i should've started with water. thought i had accounted for everything beforehand.
Quote: Originally posted by Herr Haber  
Looking at the video it also looks like a closed circuit. Is it a bump or overpressure ?

bump. didn't know there was a term for it, the wiki page is very informative. not sure how I've never heard of this, it's a huge safety concern.

can you guys believe all my glassware survived the ordeal?


Rainwater - 15-2-2022 at 14:31

Quote: Originally posted by SnailsAttack  

can you guys believe all my glassware survived the ordeal?

Nope. Better get a polized filter and inspect that glass.
https://m.youtube.com/watch?v=7UY9q0-8vBg
https://www.amazon.com/Best-Sellers-Camera-Photo-Lens-Polari...

[Edited on 15-2-2022 by Rainwater]

SnailsAttack - 15-2-2022 at 18:43

Quote: Originally posted by Rainwater  

Nope. Better get a polized filter and inspect that glass.
[Edited on 15-2-2022 by Rainwater]

nuts. you think this lens would be sufficient? i dunno nothin about optics

Herr Haber - 16-2-2022 at 02:18

Quote: Originally posted by SnailsAttack  

bump. didn't know there was a term for it, the wiki page is very informative. not sure how I've never heard of this, it's a huge safety concern.

can you guys believe all my glassware survived the ordeal?



It's a big concern but less if you prepare for it.
But in your case, that's because of the 300c flame heating a very small volume of a low boiling point liquid. Moving the flame constantly might have helped.
Nowadays there are less and less alcohol lamps and bunsen burners. I've seen "electric bunsen burners" for schools.

If you decide to invest in some hardware I'd recommend a stirrer / hotplate. It wont prevent your aparatus to bump and jump around like a wild washing machine but it will allow you a lot more than a naked flame and make things a lot easier on you.

If you go that way and also get some more glassware there's some really good advice on this page to improve your safety.
There are several threads on the forum that are pretty interesting on related subjects (to stress test or not to stress test your brand new glassware?).
In my opinion it's a pretty good idea (for example) to distill water under reduced pressure *before* doing it for real with acid or a flamable.

Oh and congratulations on your brand new food coloring stains. A few burn marks and spills on your workspace are unavoidable ;)

Rainwater - 16-2-2022 at 08:27

Any polarized filter will do. Amazon has everything but is far from the only source. Old lcd screens have them. As well as hobby lobby. Cheaper the better in my opinion!

Sulaiman - 16-2-2022 at 08:33

if a hotplate/stirrer is not in your budget,
for test tube scale heating I like to use Ikea tealight candles
https://www.ikea.com/my/en/p/glimma-unscented-tealight-80388...
anything equivalent should be good.
hold the glassware above the flame to avoid soot,
the hot air above the flame is sufficient for most purposes.

teodor - 16-2-2022 at 11:31

SnailsAttack, it would be much safer to use boiling water to heat your apparatus. Very convenient is to use an electrical kettle. Some of them even have a mode of keeping water at a specific temperature, but you can just turn it on/off periodically. Such kind of water bath should be enough for distilling acetone or methanol, for ethanol and isopropanol it is generally not so great but in the case of your small apparatus, I suspect it could be suitable.