Sciencemadness Discussion Board

Purifying glycerol propylene glycol mixture

TheMrbunGee - 30-10-2017 at 06:26

Hey SM,

I did something really stupid, and ruined about 4 liters of e-liquid (75% glycerol, 24% propilene glycol and about 1 % of some volatile aromatic stuff by volume, and I have about 8g of nicotine as well in there)

What I did - I poured all of it in 5 liter bottle (because I wanted to mix different ratio mixtures) and heated it all in water bath, but the bottle was too close to heat source and something form PET bottle went in to glycerol/PG mixture. and it all tastes like plastic now.

What I have in mind Is to purify it now (because that stuff is worth about 200 euros and up).

I am going to distill it, but my question is - should I add some activated charcoal or something to suck up that PET nastiness? could it alter any of substances I have in liquid?

Thanks!

Melgar - 30-10-2017 at 06:47

It's not PET, actually, it's polyvinyl alcohol. There's a layer that's polar on the inside of soda bottles, (polyvinyl alcohol) that repels nonpolar molecules, specifically CO2, because otherwise, the CO2 would all leak out and it would go flat. You could probably remove it by filtering through activated charcoal. PVA molecules are quite large, and would stick to the charcoal, although you may end up clogging a few filters getting it out. That should get out all the PVA though, and you shouldn't need to distill it. Not sure what your "aromatic stuff" is, or what would happen to it going through a charcoal filter, though.

For future reference, it wasn't the heat that did it, although the heat would have sped up the process. The semi-polar liquid would have dissolved the PVA's nonpolar coating, then proceeded to dissolve the PVA. You just shouldn't store any organic solvents in PET bottles that were meant for food or beverages in general, although storing them in, say, old PET cooking oil bottles might be okay.

[Edited on 10/30/17 by Melgar]

TheMrbunGee - 30-10-2017 at 07:04

Ohh, that changes things.. But I have some doubts still, because I stored the liquid in the same kind of bottle for months and it was fine. The bottle originally contained still water..

Okay, I will try to filter some of it without distilling first!

EDIT:
yes, seems like you are very correct! and I messed up, so I mixed liquids in a 5l bottle and poured in to 2 two liter bottles, one of them contained still water - other carbonated. and the liquid from still water bottle is fine! so I have only less than 2 liters to clean up! :D


Thanks, I'll try the filtering, when I will get the charcoal.


EDIT2:

Nope, the taste comes from 100ml dispensing bottles I got from ebay, the liquid from carbonated water bottle is fine too. there's that. I will write a review. :D

Thanks! :)
[Edited on 30-10-2017 by TheMrbunGee]

[Edited on 30-10-2017 by TheMrbunGee]

Melgar - 30-10-2017 at 07:22

Quote: Originally posted by TheMrbunGee  
Ohh, that changes things.. But I have some doubts still, because I stored the liquid in the same kind of bottle for months and it was fine. The bottle originally contained still water..

Okay, I will try to filter some of it without distilling first!

You say "same kind of bottle", but are you sure about that? One of those lightweight PET water bottles wouldn't have a PVA layer, for example. Many other bottles do, even if the stuff in them isn't carbonated, because it also keeps out oxygen that could get in. By "still water", do you mean "distilled water"?

Thinking about it, the nonpolar layer on top of the PVA could be another culprit, but is probably thin polyethylene or PET. If it looks like there's a plastic layer peeling off inside it, you might be seeing the nonpolar layer separating from the PVA, and the PVA is thoroughly dissolved in your liquid.

TheMrbunGee - 30-10-2017 at 07:28

Quote: Originally posted by Melgar  
Quote: Originally posted by TheMrbunGee  
Ohh, that changes things.. But I have some doubts still, because I stored the liquid in the same kind of bottle for months and it was fine. The bottle originally contained still water..

Okay, I will try to filter some of it without distilling first!

You say "same kind of bottle", but are you sure about that? One of those lightweight PET water bottles wouldn't have a PVA layer, for example. Many other bottles do, even if the stuff in them isn't carbonated, because it also keeps out oxygen that could get in. By "still water", do you mean "distilled water"?

Thinking about it, the nonpolar layer on top of the PVA could be another culprit, but is probably thin polyethylene or PET. If it looks like there's a plastic layer peeling off inside it, you might be seeing the nonpolar layer separating from the PVA, and the PVA is thoroughly dissolved in your liquid.


by "same kind of bottle" I meant from the same manufacturer containing the same water and by still I meant not carbonated.

And I figured out that the smell/taste comes from these!

Melgar - 30-10-2017 at 08:01

It's just residue from manufacturing, then. Store acetone in them overnight and they'll probably be fine the next day.

TheMrbunGee - 30-10-2017 at 08:28

Quote: Originally posted by Melgar  
It's just residue from manufacturing, then. Store acetone in them overnight and they'll probably be fine the next day.


I'll do that, thanks!