Friday 11 December 2015

Dichloromethane from paint stripper

Dichloromethane, also called methylene chloride or simply DCM, is an extremely useful organic solvent with the formula CH2Cl2. It's a very volatile colourless liquid with a heavy sweetish smell, similar to chloroform.

I'm in urgent need of it and I can't find anywhere to buy it cheaply so I thought I'd try extracting it from paint stripper. I purchased 500ml of "Selleys kwik strip". According to the material safety data sheet (MSDS) the stripper contains:

>60% dichloromethane
10-<30% ethanol
1-<10% light aromatic petroleum
1-<5% aqueous ammonia
And "additives" to 100% (presumably cellulose-derived gelling agents)

I poured 250ml of the "kwik strip" into a large round-bottom flask and setup for distillation. I kept the distillation temperature around 60 C and after no more product came over, I stopped the distillation.
I believed the distillate contained mostly ethanol and dichloromethane, so I washed it with twice its volume of water to remove the ethanol. I was left with a nice amount of usable dichloromethane.

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