04-06-04 14:31
No 499408
SWIM wants to do a bit of a chemistry exercise and separate 1-methoxy-2-propanol acetate BP 145C from a higher boiling compound BP > 200C via distillation.
SWIM read the MSDS for 1-methoxy-2-propanol and found that it's flammability is not horrible but it could form peroxides and blow up.
SWIM can ensure no leaks in his system, will only use electric (no spark) heat source with no ignition source in room, knows not to distill to dryness (although about 50% of mixture would remain in flask anyway as SWIM would not distill that) and can do this at 1 atm or under water aspirator.
For those with more experience, is it any safer to do this under vacuum or at 1 atm? Or no difference? SWIM is not concerned with time & effort for this one so much as safety. Different MSDS sheets give different account of the risk of this compound and so SWIM was just hoping some much smarter bee could give some advice or relative risk assessment based on experience.
(Chief Bee)
04-06-04 15:50
No 499417
If you aren't going to distill to dryness, then the peroxide risk would be rather low in my opinion.
From the peroxide decomposition viewpoint, it would be safer to perform a vacuum distillation (as the boiling points go down under vacuum, you would heat it less), but when vacuum distilling there is always a risk of glassware implosion (very small risk if you heat your flasks evenly, and inspect for cracks/scratches). With this I just wanted to say that no procedure is 100% safe, not that this procedure would be significantly more dangerous than any other.
My suggestion would be that you perform two distillations, one at 1 atm, and the other one under vacuum - then you get to practice both techniques and will notice how much the boiling points will differ at certain pressures.
The Hive - Clandestine Chemists Without Borders