Purifying OTC Chemicals: Simple Distillation

This is the first in a planned series of videos on techniques for purifying OTC (over-the-counter) reagents.

This first one is simple distillation, used to purify and separate mixtures of liquids. If you have a mixture of liquids where the components have sufficiently different boiling points, simple distillation can be used to separate them. The component with the lower boiling point will vaporize first. As long as you keep track of the temperature of the vapor, you can stop the distillation once it rises above the boiling point of the component you want. That way, you end with a fairly pure product.

Category:

Science & Technology

Tags:

• acetone
• distillation
• chemistry

[98JMA]

Unless you are certain that your product will come over first, never plug the receiver vessel in securely . . .if something else comes over at a lower temp. then it will be a right pain in the arse to get the flask off quick and install a new one for your pure product.

Always throw away the first 20ml or so of a distillation as it may be impure, having come through the apparatus first. Once it has come over, the system has been flushed with the purified product and it is suitable to collect.

[mrhomescientist]

@98JMA All great points! I never took advanced chem lab at college so there's lots of little things like that that I tend to miss. I'll do that in the future. Thanks!

[mcwario13]

watch?v=4T0-b1QQ0ek&feature=g-­all-lik&context=G28abf4aFAAAAA­AAAQAA is that you?

[mrhomescientist]

@mcwario13 It is! That's part of a science outreach program I do to get kids interested in science and technology careers. That's funny you found it :)

[NoromiEnki]

My only concern is that the setup doesn't have any outlet to relieve sudden increases of pressure. In this case, since there's no grease on the joints, it might escape around the joints, or force out the one joint that isn't Keck clipper, your thermometer. In general, though, it's a good idea to include a 105 degree vacuum take-off adapter at the end between the condenser and receiving flask.

I'm not hating, just a tip to keep things safe for the future.

Love the videos, keep it up man!

[mrhomescientist]

@NoromiEnki Thanks, those are very good points. I actually do have that adapter, just didn't use it for fear of losing product. But now that I think about it, all vapors should have condensed by then anyway so it really is just a safety feature. Every time's a learning experience, and I'll remember that for the future. Thanks for the input!

[AlChemicalLife]

hey can u come to my school. it would be vary cool for the science brothers to come to my school.iv ben wanting pepole to see what chemistry is all about and how fun it is. and it would be cool to meat u guys too :) . thx if u can do it i can send u a website url to my school.

thx

Alchemicallife

[98JMA]

@domvasta

Yes.

[98JMA]

@mrhomescientist

If you really are worried about losing products, just put a long rubber tube onto the end of the pressure-release hole/tube on the 105* adapter and lead it into an open flask.

[michalchik]

You distillation would be even more efficient if you added a little hydrogen peroxide and sulphuric acid ;-).

On the serious side, you should mention that using fresh acetone is important to avoid concentrating peroxides. Otherwise great video.

[domvasta]

you can get rid of the 2-3% water by drying with CaCl2 or MgSO4