Orsyn
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Plasticizer ID
So while trying to duplicate a previously successful extraction of Phthalic Acid from some vinyl gloves, I cut up a shower curtain and soaked it in
%70 ISO for a day, then started adding lye water as I did previously to get an aqueous layer containing my phthalate, except this time instead of
simply separating out into two clear layers, I got a heavy-ish, white granular precipitate in the water which is obviously brought out by the NaOH.
Some sort of crystalline salt it seems, it's still not completely dry.
Acidifying with HCl, boiling down and then chilling the separated, filtered aqueous layer to about 3C so far hasn't brought any crystals, as I've
before seen while running this same routine on gloves, so this seems to be the plasticiser, and it sure smells much like my previous extractions, but
I wonder if anyone might know what this is? Maybe a different Phthalate? Unfortunately I don't have a good thermometer at the moment, so I can't take
an mp unless I do it by comparison to another known mp if that makes sense.
Any ideas? I'm thinking about melting a bit to see what the crystal structure looks like, but I figured I'd ask you guys first..
edit: Whatever it is has a pretty high melting point, seems to be above about 250C which is the ceiling for my lamer hot plate.
I'm thinking about treating a little bit with HCl to see what happens.
Aren't most plasticizers a liquid at room tempertures? I think I read that somewhere but I'm not sure..
[Edited on 30-5-2015 by Orsyn]
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Orsyn
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So mostly coz I'm not sure what else to do with it, I acidified with some HCL in DH2O, then neutralized and chilled to see if I could get any pretty
crystals, and all I really have is a small mess, so I guess I'm gonna just abort this run for now, I have another batch of the alcohol that I'll save
for a while just in case I can figure out what this stuff is, and if it's at all useful for making phthalimide (or something else interesting).
If anyone cares it was a clear shower curtain, but it did have some multi-colored graphics impregnated in it. The shit smelled just like a previous
& successful extraction while soaking, so even though a small test pretty much failed, I was pretty sure this stuff was full of DEHP. Guess snot..
edit: oh ya I put some in a small glass tube and tried to melt it, it's mp exeeded my hot plate, so it must be north of 240C.
Off to the dollar store..
cheers
[Edited on 31-5-2015 by Orsyn]
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blogfast25
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Quote: Originally posted by Orsyn  | | So while trying to duplicate a previously successful extraction of Phthalic Acid from some vinyl gloves, I cut up a shower curtain and soaked it in
%70 ISO for a day, |
At room temperature, this may well not be long enough to get complete extraction. 30 % water does nothing for the extractive properties of the
solvent, BTW.
What were the ratios of (presumed) pPVC and IPA?
I think you're cutting corners and it's not working.
[Edited on 31-5-2015 by blogfast25]
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Orsyn
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Surely not enough to get it all, but 24hrs + agitation is certainly enough to get some of it, and in the past, it's yielded ok after ~24hrs.
Unfortunately I don't have a soxhlet extractor..
As I said, I'm repeating a previously successful extraction, the only thing that's changed this is the medium I'm extracting from (previously, gloves;
now its shower curtains).
I may have used a little heat last time, but the PVC is getting noticably stiffer and opaque, and I'm not seeing any sign of DEHP, although I sure
thought I smelled it, but that must be something else.
At this point I have no idea how much DEHP should be in these products, once I nail a good and inexpensive source down, I'll start weighing.
| Quote: | | I think you're cutting corners and it's not working. |
And I think you could probably improve on your comprehension of what I've written.
;-)
[Edited on 31-5-2015 by Orsyn]
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blogfast25
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It wasn't a criticism, more an attempted explanation.
You don't need a Soxhlet either. Just an RBf with decent condenser: simmer under reflux for a while. That's what I did.
I think it also helps to distil off most of the solvent, that's also what I did. Recycle the IPA (I used cheap MeOH).
The DOP (DEHP) content is usually somewhere between 15 and 25 w%.
The alkaline de-esterification of the ester can take a while too: simmering under reflux will help to speed it up.
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UC235
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I did some Soxhlet extractions of plasticized material and found shower curtains only had about 10% bis(2-ethylhexylphthalate) while gloves had about
30%. PVC itself has weak solubility in the iPrOH and caused some issues when water was added to the post-extraction liquid.
You mention NaOH and HCl being added. Is it possible that your solid is NaCl?
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Orsyn
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I don't think the precip is NaCl, in fact I just tasted a micro-crumb and it's too bland, it also crashed out before I added any HCl.
Concentrating the alcohol is an idea. It still seems like I should have gotten *some* phthalate back.
| Quote: | | The alkaline de-esterification of the ester can take a while too: simmering under reflux will help to speed it up. |
I've wondered about this. I do boil it awhile after the NaOH additions, but I wasn't sure how necessary it was, so thanks..
I found a huge, heavy chinese made curtain for cheap and I'm running a small test on it now, if it works the price will be MUCH better than the
gloves, which can be a little $$ I've noticed..
Also yes I know the %70 won't extract as well, but it's cheap and after soaking I just basically add the lye in directly. I can get pure ISO but it's
quite a bit more expensive. I'm not in a huge hurry here and I can just run 2-3 extractions if neccessary,
[Edited on 31-5-2015 by Orsyn]
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blogfast25
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Remember also that the de-esterification should also yield the alcohol. I doubt if the alcohol is soluble in 70 % IPA. So you should get an oily
layer. If not, that's a sign your de-esterification hasn't proceeded. With DEHP that definitely happened to me once.
When you add NaOH to IPA you get the corresponding Na alkoxide. That's the base that does the work but the IPA alkoxide is a weaker base than e.g. Na
methoxide or Na ethoxide. And with the ester being highly stable, a strong base is needed to carry it off in a reasonable time, I think...
[Edited on 31-5-2015 by blogfast25]
| Quote: Originally posted by UC235 | I did some Soxhlet extractions of plasticized material and found shower curtains only had about 10% bis(2-ethylhexylphthalate) while gloves had about
30%. PVC itself has weak solubility in the iPrOH and caused some issues when water was added to the post-extraction liquid.
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Plasticiser content 'regulates' hardness, so if you can have some subjective measure of that, use it to select the softest objects. Gloves are indeed
often softer than curtains.
[Edited on 31-5-2015 by blogfast25]
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Orsyn
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I actually did have a small amount of brown oil form on top of the water this time that I hadn't seen before, no idea what it was. That stuff has been
dumped but I still have the top solvent/alcohol layer soaking on the same curtain.
Whatever this stuff is it came out immediately upon the addition of the lye-water, I thought it was an emulsion forming at first, but it all came over
with the water once that separated out, and then there was so much of it I thought it might be a PITA to filter, but it actually filtered out pretty
easily w/out vacuum.
:shrug:
I still wonder what it is I'm smelling, some product of this breakdown is really kinda sickly-sweet smelling to me, very strong, it would make me ill
pretty quick..
[Edited on 1-6-2015 by Orsyn]
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blogfast25
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An anti-oxydant? A dye? Co-extracted and hydrolysed? Just guessing here...
The DEHP I extracted, then boiled down the solution, was kind of reddish. DEHP is colourless, of course...
Why not try and use clear, denatured Ethanol as a solvent? Cheap and should work better than IPA? Na ethoxide is a strong base.
[Edited on 1-6-2015 by blogfast25]
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