Sciencemadness Discussion Board

Distilling from a viscous mixture

cnidocyte - 30-1-2011 at 09:34

I'm distilling DCM from a viscous paint stripper at the moment and I have about half a pint of DCM (the hot plate is only set to 60C so I don't think theres enough heat for the methanol yet) but this mixture is getting more viscious by the minute. It looks pretty cool how slowly the bubbles are rising. Does anyone here have experience with distilling the DCM out of these viscous paint and varnish thinners? Is it difficult to clean this stuff out of the boiling flask after you've distilled a significant amount of the DCM out? This stuff was thicker than maple syrup before I started distilling so it will probably be near solid when I'm done.

Magic Muzzlet - 30-1-2011 at 09:46

It's already been covered and it's no problem to get out of the flask, distillation has always gone smooth for me.

cnidocyte - 30-1-2011 at 12:41

I distilled about 400mL of DCM out of 1L of stripper and decided to settle for that and when I cleaned the flask out I poured most of it out and was left with some jelly on the walls of the flask. Got that stuff out pretty easy with a bottle cleaner. I think I could of got a fair bit more DCM out of it if I kept distilling, I wasn't expecting to get this much at all. This seems to be a decent OTC source of DCM.

bbartlog - 30-1-2011 at 12:57

Seems like adding a somewhat higher-boiling liquid that also functioned to thin out the mix would be the way to go if you feel like some DCM is getting left behind in the syrup. Of course this would mean sacrificing whatever it was you added, so I don't know how economical such an approach would be. Ethylene glycol might work.

watson.fawkes - 31-1-2011 at 06:44

Quote: Originally posted by cnidocyte  
I'm distilling DCM from a viscous paint stripper at the moment
FYI. If you can get a pasty formulation with DCM in your area, you can likely get a liquid formulation with DCM also, although perhaps not at the same store. The main impediment is generally regulatory, so if you can find one, you can usually find the other. Clearly, the liquid formulation is easier to distill.

cnidocyte - 31-1-2011 at 10:58

Quote: Originally posted by watson.fawkes  
Quote: Originally posted by cnidocyte  
I'm distilling DCM from a viscous paint stripper at the moment
FYI. If you can get a pasty formulation with DCM in your area, you can likely get a liquid formulation with DCM also, although perhaps not at the same store. The main impediment is generally regulatory, so if you can find one, you can usually find the other. Clearly, the liquid formulation is easier to distill.

I know one product which is a liquid formulation but its twice the price for some reason. Next time I'll just pay the extra money though because with the liquid formulation I'll be able to recover all the DCM and probably the methanol too.