spong
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NMP from paint stripper
I was spending far too much time thinking about where I could find DMF and then I noticed that a few paint thinners use NMP which works just as well
in most situations. I bought a tin of polystrippa paint/varnish remover (the DCM free version) and planned to vacuum distill it from the thick syrupy
goop.
The thinner:
Into the flask (yes I'm using boiling stones under vacuum, yes they did not work very well and there was plenty of bumping  )
The setup with my fridge pump I snagged from a bin at uni  :
The goop first starting to boil:
It didn't boil as nicely as that the whole way through, most of the time it would bump and form big bubbles but none made it into the condenser.
Firstly something came over at about 60C, my fridge pump isn't THAT good, I'm guessing it was something else in the thinner, too high for water,
perhaps a fragrance. It had an orange scent I think so that could be it. The boiling point then stayed around 80-90 for the rest of the distillation
which is most likely NMP.
First drips:
The finished (for now) product:
The fragrance will have to be removed somehow, perhaps a fractional vacuum distillation if my fridge pumps are up to the task. Can someone do their
best to describe the scent of NMP? I can smell something aminoniaish but there's some fake orange/citrus smell in there too (not limonene, that smells
amazing )
[Edited on 18-10-2010 by spong]
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HexJam
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Great post, think I might try this myself!
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mr.crow
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Very Good
NMP can also substitute for DMSO and doesn't turn stinky over time.
Double, double toil and trouble; Fire burn, and caldron bubble
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spong
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After leaving the bottle overnight, two layers have formed, they're very hard to notice but I had worried about that when I poured it into the flask,
it didn't pour like a pure substance. The top layer, I'm pretty sure is limonene, it doesn't smell as nice as limonene but that's probably because
it's mixed with NMP fumes. I moved a small amount of each liquid into a test tube, water was added which caused an obvious separation of the layers,
the cloudy water/NMP in the bottom and the limonene on the top. The top layer was removed, it burned just like limonene, sooty orange flame, quite
flammable. The bottom layer had the water boiled off and burned with a clean, weak blue flame. I'm going to do some reading and make sure no
azeotropes of water/NMP are formed but if not I'll do the same on a larger scale, boiling the water off then vac distilling the NMP over.
The label did say 60% NMP (There is no MSDS for this product), I had assumed the rest was polymer but they mean 60% NMP and 40% limonene, the polymer
doesn't count apparently. It's the same with 87% DCM and 13% MeOH in another paint stripper.
EDIT:
I removed the limonene from the rest of it, around 30ml water was added to the mix in a separatory funnel, the bottom layer was kept and the limonene
drained off into another jar until I find a use for it.
Mix before water (the border between the layers is just barely visible)
After addition of water:
Separated:
Vac distilling again(this was a huge pain in the ass, I used a capillary tube to stop bumping but the hole was a bit too big and because of the water
present it would not cleanly boil for some reason, eventually the water boiled off and only the NMP was left, not much of the water was separated
though, it will have to be dried thoroughly with a dessicant before use)
Finished:
When I distill the rest of the can I think I'll skip the addition of the water and just try to separate the layers, either carefully in a funnel if
the limonene is not soluble in the NMP or by fractional vacuum distillation if it is.
[Edited on 19-10-2010 by spong]
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Magpie
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Nice work, spong. This looks like an interesting solvent that may I may well need sometime. Does anyone know what US brands of paint stripper use
NMP as solvent?
The single most important condition for a successful synthesis is good mixing - Nicodem
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Magpie
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FYI, here's one US product, complete with orange dye, citrus smell, esters, gel, and an MSDS:
http://www.wmbarr.com/citristrip/default.aspx
I have no idea how difficult it would be to isolate NMP from all the other additives in Citristrip.
The single most important condition for a successful synthesis is good mixing - Nicodem
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mr.crow
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Gorilla PVC Glue in the states also uses NMP
You can mix the glue with water to get rid of the plastic resin, boil off the water and vac distill.
Double, double toil and trouble; Fire burn, and caldron bubble
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Eclectic
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isopropanol and salting out works for separating the NMP from the methylcellulose? thickener.
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entropy51
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Ye gods and little fishes!
Screen names for the members I can understand, but now screen names for the chemicals?
A thread about a useful chemical on a chemistry forum, and nowhere was anyone polite enough to mention that ugly word "N-Methyl-2-pyrrolidone ", which
is what I think you guys are talking about. If you must use acronyms, at least define them the first time used.
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Magpie
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Yes, I had to look it up too, by searching paint strippers. NMP is all over this board so I thought I must be the only one who
doesn't know what it is.
BTW entropy, you will be glad to know that I'm now tending a little batch of sulfanilic acid per Brewster.
The single most important condition for a successful synthesis is good mixing - Nicodem
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entropy51
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Quote: Originally posted by Magpie  |
BTW entropy, you will be glad to know that I'm now tending a little batch of sulfanilic acid per Brewster. |
Yes! I finally ran a Brewster prep before Magpie.
I'm sure you will get a higher yield, however.
Did you distill your aniline first? If not, your product may be a tad off-color.
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spong
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That sounds almost identical to the one I had, NMP (or n-methyl-pyrrolidone to you entropy ) limonene, orange dye and thickeners.
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