Sciencemadness Discussion Board

Ghetto distillation apparatus I'm testing

cnidocyte - 2-12-2010 at 11:48

I have a boiling flask clamped into a water bath. The flasks stoppered with a rubber stopper with rubber tubing through it. The other end of the tubing leads to a glass bottle in an ice bath. Its a pretty cold night, there was plenty of snow for my ice bath and the cold air is probably as effective as cold water running through a condenser. The water is at 80C but I don't seem to be getting any condensation in the rubber tubing yet. The methanol has expanded a lot, I over filled the flask so that there will be little room for vapour to occupy but I might have to empty some of it if it keeps expanding.

EDIT: I emptied some of the liquid out to be on the safe side. Its a long neck RB flask but even still it was nearly to hot to handle with bare hands and I got a whiff of alcohol vapour so its definitely heating but I'm only starting to see condensation in the rubber tubing. Its only about 3cm outside the rubber stopper.

[Edited on 2-12-2010 by cnidocyte]

Justin - 2-12-2010 at 14:39

try any kind of metal pipe for a condenser, metal conducts heat, rubber insulates. Plus rubber will be attacked by the methanol. But until then just crank the heat up and have your water bath boiling.

ghetto to ghetto

cyanureeves - 2-12-2010 at 18:17

hey!moonshiners always use copper.wouldnt yellow tubing used for gas lines nowadays work?its not pvc. substitute the rubber by using teflon tape wound around the tubing until its snug. you say its cold where you live?just wrap an old wet rag around the tubing for condenser. air lines used in shops are already coiled. i used one of those to make ammonia by distilling deer hoofs.at least you have a flask. i used an old paint can stoppered with a piece of ashwood and a hole in the center.all while uncle jed just proudly nodded in approval.

bbartlog - 3-12-2010 at 07:25

Quote:
try any kind of metal pipe for a condenser, metal conducts heat, rubber insulates.


But since his problem seems to be that he's not able to drive enough heat into the methanol (it's condensing as soon as it hits the tube), this would be the opposite of what he needs. Having a tube with good heat conduction is only desirable for the section where you want the stuff to be condensing.

In my experience distilling with a water bath is frustratingly slow (except for really low-boiling stuff e.g. chloropropane); I'd use direct heat or an oil bath for faster heating.

cnidocyte - 3-12-2010 at 08:36

Didn't work at all unfortunately. First time I tried this I got condensation half way up the tube but this time it barely made it 2cm up. The water was at 90C but the liquid in the flask never boiled. Weird because I had the whole flask submerged in the water. I'm gonna try again today and I'll use a heat gun to give it a bit of a boost. I'll test out those condenser ideas in the future but for now my obstacle is getting the vapour into the tubing. Methanol boils at around 65C so the water bath shoulda been more than enough to get some methanol vapour into the tubing. I didn't smell any alcohol at all so I don't think there was any leakage with the stopper.

I'm gonna try direct heat with a FB flask.

cyanureeves - 3-12-2010 at 13:29

goodness its just heat youre lacking?how wide is your hose anyway?i wouldnt think making stout alcohol would be so tough. theres even water distillers that can make alcohol and theyre composed of plastic.they can actually make 180 proof i hear. you sure are babying that rb flask.well i would too i guess.time to chop down that ole mesquite.

bbartlog - 3-12-2010 at 17:58

What percentage methanol is your solution?
Anyway, a water bath that is only 25C hotter than the boiling point of your material is going to transfer heat painfully slowly. Try boiling water with an oil bath heated to only 125C and you'll see similar results, or lack thereof (at least with borosilicate glass; obviously thin-walled metal containers with stirring of the bath might make a huge difference).

cnidocyte - 10-12-2010 at 16:31

Quote: Originally posted by cyanureeves  
goodness its just heat youre lacking?how wide is your hose anyway?i wouldnt think making stout alcohol would be so tough. theres even water distillers that can make alcohol and theyre composed of plastic.they can actually make 180 proof i hear. you sure are babying that rb flask.well i would too i guess.time to chop down that ole mesquite.

Seems to be. I was warming some methylated spirit for another experiment the other day and I noticed when I put a beaker with a small amount into hot water, vapour began to rise out of the beaker instantly. When I had the beaker filled with it though, I didn't see any vapour rise at all. All those -OH bonds give alcohols a high heat capacity I'm guessing. I think the reason my last distillation experiment failed was just a matter of time. I didn't leave it long enough for the contents of the beaker to heat up. The reason I got vapour halfway up the tube the first time I tried it was because I didn't put such a large volume of the liquid into the flask that time.

cnidocyte - 16-12-2010 at 14:01

I tried this with an oil bath and it worked. This time I had the contents of the flask boiling in no time. The process seemed to be just as fast as the distillations I've done with proper glassware. After a few minutes I had a few mils of alcohol in the bottle. Oil baths scare me, I couldn't help wondering what would happen if the boiling flask shatter and all the polar contents of the flask was emptied into the oil. Dunno if I'd have time to get the hell outta there without getting burned. I didn't add any anti bumping chips to the oil and I observed some heavy bumping when it got up around 90C. That was the first time I used an oil bath, I didn't think viscous liquids bumped so heavily, next time I'll make sure theres nucleation sites in there.


[Edited on 16-12-2010 by cnidocyte]