watson.fawkes
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OTC source of technical THF
The question first: Anybody know of a source for technical-grade THF (tetrahydrofuran) that's over-the-counter retail at an ordinary kind of supplier
(probably industrial)? I'm in the USA.
Here's what I'm trying to do. I've got some old Kydex parts that I want to rework, and I need some glue. The manufacturer doesn't sell a ready-to-go
glue, but does have a technical note on bonding the sheet material. It talks about making up a glue with 50% THF and 50% MEK (methylethylketone) and shavings of the
plastic. I can pick up MEK at the hardware store, but not THF. I don't need to pay for reagent grade, certainly.
My current plan is to try to find some IPS 1007 cement, which is mostly the same solvent composition which some PVC resin dissolved. That will work, certainly; it's recommended by the
manufacturer. Marsh Laboratories seems to have a fair bit of market share for THF-based cements, particular for bonding sheet (not pipe), but they don't sell
these retail and information about these products of theirs is not on their web site.
So. Any ideas?
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smuv
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You could also find a formulation that has THF in high concentrations without any other components with a similar boiling point, and just distill off
the THF. You might want to do this with a disposable, jerry-rigged still pot to avoid the mess of PVC resin which would remain.
I have considered purifying THF from PVC cement for solvent purposes, here is the product I found to have the highest THF composition, with the
absence of anything that will interfere with rectification. This distillation could likely be done without much reflux or a fractionating column.
Product
MSDS
Another option, easier but more prone to failure, would be to take the PVC cement, and add water to it, hopefully forcing most of the PVC resin to
precipitate out (as THF is miscible with and MEK is fairly soluble in water). Assuming most of the PVC precipitated, you could decant the solution,
then salt out the MEK and THF and dry them over a suitable descant (probably CaSO4 or MgSO4 are best).
"Titanium tetrachloride…You sly temptress." --Walter Bishop
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kclo4
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| Quote: | | Another option, easier but more prone to failure, would be to take the PVC cement, and add water to it, hopefully forcing most of the PVC resin to
precipitate out (as THF is miscible with and MEK is fairly soluble in water). Assuming most of the PVC precipitated, you could decant the solution,
then salt out the MEK and THF and dry them over a suitable descant (probably CaSO4 or MgSO4 are best). |
I like that idea! However, you would still need to distill since the MEK and THF would still be mixed. Unless they salt out at different times? then
maybe you could separate them I guess?
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smuv
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He wants a mixture of MEK and THF in the first place...
"Titanium tetrachloride…You sly temptress." --Walter Bishop
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Sedit
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Many of the cleaners used for plumbing such as the purple primer and some clear forms are nothing more then THF and MEK anyway. Some you find may have
acetone also but a quick look will tell which is just MEK and THF. Im not sure what the percent of the mix is though but mixed with the plastic he
talks about it make act just like the glue he needs.
[edit]
Decided to look into it for you,
http://householdproducts.nlm.nih.gov/cgi-bin/household/brand...
Clear primer 85% MEK the remainder being cyclohexanone and THF. Others have higher contents of THF some as high as 60% but there are many other
impuritys to contend with in those
[Edited on 8-3-2009 by Sedit]
Knowledge is useless to useless people...
"I see a lot of patterns in our behavior as a nation that parallel a lot of other historical processes. The fall of Rome, the fall of Germany — the
fall of the ruling country, the people who think they can do whatever they want without anybody else's consent. I've seen this story
before."~Maynard James Keenan
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kclo4
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Oh sorry I didn't see that, I kind of skimmed though the post.
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Globey
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Primers and cements could also be good source of cyclohexanone. You could do one big dirty distillation (get more of the VOC's) by distilling using
maybe a gallon can as your retort, and further purify the VOC's using bisulphite-adduct and(or) more careful fractionation. The THF won't form a
complex w/ the bisulfite.
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beerwiz
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Sourcing Tetrahydrofuran OTC?
Anyone know of a way to source pure Tetrahydrofuran over the counter?
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Mailinmypocket
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It can be distilled from that yellow PVC plumbing cement I believe. It might make a hell of a mess of your glassware though.
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Praxichys
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It is a component of PVC primers, but in a mix which is difficult and expensive to separate.
Your best bet would be Ebay. It's not "over the counter" but I do not know of any other sources of THF which are reasonably pure.
A discussion about synthesizing it from furfural obtianed from oat bran or corn cobs has been discussed here before.
http://www.sciencemadness.org/talk/viewthread.php?tid=15774
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subsecret
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Here's the MSDS for a generic "purple primer."
http://facilities.fit.edu/documents/forms/MSDS/Oatey%20Purpl...
Fear is what you get when caution wasn't enough.
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bfesser
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