Zeitgeist
June 1st, 2004, 07:34 AM
I've noticed, googling, that there's a type of P-type PVC cement that contains THF. Has anybody tried distillation of the stuff, or any other sources?
megalomania
June 1st, 2004, 04:07 PM
There is a thread at the Hive about distilling THF from PVC cement... I shall reproduce it here. Watch out though, such a distillation is likely to be dangerous as the thread shows:
Distilling THF from pipe cement
I've gone through the search engine, and haven't found any information on how to distill pipe cement to get the THF and the other solvents out. As Ab2 said in another thread, that if one was to use their glassware to distill this stuff, one would need all the recovered THF just to clean the flask...
I'm thinking about distilling it straight from the can using a water bath.
Has any one got experience doing this? What did you use? Did you do anything to prevent peroxide formation?
This is a 16 fluid oz can of a popular brand of gray PVC cement mentioned elsewhere on the Hive in other threads.
I'm thinking that it might be worthwhile to obtain another source of THF. This looks a lot worse than distilling the DCM-containing goop that's sold as paint stripper.
Elementary
(Hive Addict)
06-25-02 15:08
No 325131
Solvents
After looking at some MDMS data for various PVC cements these seem to be the solvents used :
Methyl Ethyl Ketone (40-55%) (BP = 79.6°C)
Tetrahydrofuran (25-40%) (BP = 66°C) SEE NOTE
Cyclohexanone (5-10%) (BP = 155.6°C)
Acetone (0-5%) (BP = 56.5°C)
(PVC Resin (10-14%))
NOTE : Must be distilled with a reducing agent, as explosive peroxides may form (see Merck Index).
You may have a hard time seperating acetone, MEK and THF !
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John Lennon - Working Class Hero
metwurst
(Hive Bee)
06-25-02 15:42
No 325136
H2O to start with
Perhaps a water wash is in order first. THF is soluble to 300g/L in water. The MEK and acetone are also soluble, but are both ketones, so saturating the resulting water/THF/MEK/acetone with bisulfite might crystallise them out leaving THF in water.
Sound plausible?
Elementary
(Hive Addict)
06-25-02 16:19
No 325144
:-
The PVC resin may stop a lot of the solvents from going into the water.
You may still have to distill first, to get the solvents away from the resin.
But your bisuphite addition idear seems plausable, as long as the THF does not react with the bisulphite.
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John Lennon - Working Class Hero
Ritter
(Master Whacker)
06-25-02 17:50
No 325156
WARNING!!!
Chromic:
I don't have the time to go through old posts to ref a post#, but I specifically remember one of the guys from back in the day (maybe Cheapskate?) distilling THF from PVC cement with near disasterous results. The low grade ethers in those cement products are LOADED with peroxides. There was at least one report here in the past which detailed a powerful explosion resulting from the distillation of THF from pipe cement. BE CAREFUL!! If you are going to do this, be sure to use a blast shield and have a good CO2 fire extinguisher at the ready in case the worst happens.
Better yet, PM me and I'll hook you up with a company which sells THF cheap, no questions asked.
moo
(Hive Bee)
06-25-02 22:03
No 325247
According to my memory (which is not perfect) ...
According to my memory (which is not perfect) cheapskate had an accident while reluxing the stuff, not distilling it. It is a little hard to believe that the THF used in glues would be unstabilised, after all it is intended to be used by non-chemists and has no warning labels about peroxide risk whatsoever (that would be obligatory wouldn't it?). The distillation has been performed straight from the can with a still fabricated from copper pipe, although only approximately half of the THF was distilled. Yes, there might be peroxides lurking in the can, but one could try to apply ferrous salts to the stuff to decompose them. I can't say I'm certain about this, so don't blame me if you get killed.
sYnThOmAtIc
(Hive Bee)
06-26-02 05:47
No 325434
peroxides
Well the glue is not sold to be distilled or refluxed for one. And as far as I know the peroxides are only dangerous when heated so plumbers ans plastic workers are in no danger as long as the product is being used as for what it is made for. Plus the cans do say that they contain flammable toxic solvents and to use only as directed in good ventilation. I highly doubt you could ever hold the company liable after an explosive reaction during a distillation of a product that has no place in your flask.
Chromic
(Hive Addict)
06-26-02 08:53
No 325512
Removing peroxides
What chemicals, besides FeSO4, can be used to remove the peroxides?
I may just look for another product for the THF, but I'm very interested in getting it OTC.
sYnThOmAtIc
(Hive Bee)
06-26-02 10:15
No 325549
Please
Chromic, Can you please post any info you have about removing peroxides from THF. If you have any info about nitroethane I'd appreciate it cause smiw believes he should distill it before its long life in the freezer.
starlight
(Newbee)
06-26-02 19:03
No 325677
peroxides
Vogel says you can remove peroxides from THF by:
a) passing through an alumina column
b) shaking with Iron II sulphate.
I'm afraid I'm not sure as to the practicality of these methods with regard to pipe cement as I have never seen it and am not sure of its consistency / viscosity / makeup
Osmium
(Stoni's sexual toy)
06-26-02 19:55
No 325691
Just add some motor oil and don't bother about ...
Just add some motor oil and don't bother about the peroxides. They aren't volatile and will stay behind, being safely diluted with the oil and other high-boiling stuff left in there.
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I'm not fat just horizontally disproportionate.
Chromic
(Hive Addict)
06-26-02 19:58
No 325694
Excellent
Thanx for the ideas. I'll perform the distillation on a water bath as well to minimize my troubles... rigging a still head to the can is going to take some thought...
former_chemist
(Hive Bee)
06-26-02 20:51
No 325719
Use toluene or xylene
If the mix is too thick use toluene or xylene to thin it. Both of these will be readily oxidized by any peroxides formed. Xylene has the higher boiling point so separation should be cleaner.
Hansje
(Hive Bee)
06-26-02 22:57
No 325760
water and salt
I don't know what the pipe cement they sell around your place is like, but the stuff they sell here can be extracted like this:
1. Add about three quarters of the volume of water to the cement and stir. Be amazed to see that the PVC and all other non water miscible ingredients clot together in a big ball, that, believe it or not, isn't even sticky.
2. Filter everything through a piece of cloth. Wring out to catch as much liquid as possible.
3. Add 400g of table salt per liter of added water and stir. Presto: all organics float to the top.
4. Separate.
5. Distill top layer to get THF, MEK and whatever else is in there that you want.
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Hansje high in proteine and fibre!
Cheapskate
(Downer Dude)
06-27-02 02:13
No 325809
Let me verify that
The procedure above that details adding water to remove the goop from pipe cement works quite well with the materials I have available also. I never thought of using salt to separate it though, I just distilled the entire mess.
Water did a pretty good job of getting rid of the goop though.
Chromic
(Hive Addict)
06-27-02 08:50
No 325955
Hansje
Hansje, if this works with the O___y brand of gray cement... I will love you.
Thank you!!!
isop
(Stranger)
06-27-02 16:01
No 326048
HOW do you know it really works??
Hansje,
Have you actually CHECKED that your THF obtained by adding water to kick PVC out of the solution and then salting out the THF really works?
What I am concerned about is that the plastic you see coming out after adding water are only the longest polymers and the short PVC fibers still stay in the solution.
The obvious way to test this would be to vapourise on a glass plate some of the THF obtained in this manner to see if any residue is left.
Hansje
(Hive Bee)
06-27-02 18:39
No 326082
THF
Chromic: If you have any choice, go for the glue that is used to cement narrow-fitting hard-PVC pipes together. It will be highest in THF and lowest in polymers. Over here that is a clear, tannish, very viscous liquid. The gray stuff (again: over here) is used for wide fittings and has a lot more fillers in it.
isop: Sure, the liquid obtained by the separation is by no means pure THF. But the idea is that you distill it. Collect very little below 66°, a large fraction between 66° and 75°, have some polymeric crap fall out of solution at this point (so yes: you were right about that). Left in the flask is said crap and water, that only faintly smells of solvent. I know this is not scientific proof, but what would your guess be?
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Hansje high in proteine and fibre!
isop
(Stranger)
06-27-02 20:20
No 326136
OK
Right, if you perform a distillation at the end of whatever you do, it should be OK. Didn't read your post very carefully
Chromic
(Hive Addict)
06-28-02 00:08
No 326245
Distilling THF
Thanks Hansje! Is storing the organic phase over aqueous sodium bisulfite good enough to inhibit peroxides?
Hansje
(Hive Bee)
06-28-02 10:48
No 326425
safe
I have always assumed that distilling the mixture without adding reductant is quite safe due to the considerable amount of water in there. Fate hasn't proved me wrong yet , but don't take my word for it, I'm just guessing.
You'll need to add some peroxide scavenger if you want to store your THF after distillation. Not bisulfite solution if you don't want to distill again.
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Hansje high in proteine and fibre!
Chromic
(Hive Addict)
06-28-02 16:59
No 326470
Bisulfite good enough
It seems that a sat sol'n of bisulfite forms a separate layer, and so, that's fine if I'm just using the impure THF for oxidizing with NaOCl. I might stall a bit on this procedure... I'm not as excited to oxidize THF as I once was... especially when all the dangers are taken into account... I've done some crazy stuff (like making Et2O)... but the thought of an ether and an oxidizing agent initimately together is really starting to scare me.
Antibody2
(Rehabilitated)
06-28-02 19:18
No 326523
antibody usually has abit of water in the flask ...
antibody usually has abit of water in the flask when distilling ethers (can never distill to dryness) on a water bath. Then add a couple chunks of NaOH or dry EtOH to the receiver for storage. No explosions yet.
weedar
(Hive Bee)
06-28-02 19:24
No 326525
Re:What Chromic said
I would love to see OTC GHB from this,but of course,safety
first!
Weedar
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Weedar contains 2,4-D dimethylamine salt,apparently
Chromic
(Hive Addict)
06-28-02 19:42
No 326537
The other joy of bisulfite
I awoke today, and looked at my amber glass bottle with THF in it. It was biphasic and filled with crystals! For a second, I thought "shit, this is really fucking bad..." Then a split second later, I realized, oh yeah, I had a added bisulfite to it. Looks like some of the cyclohexanone and acetone crashed out of the THF. I was just hoping for it to remove the oxygen and prevent formation of peroxides... oh well, onto distillation. (I'm not going to filter out the crystals) I want to get this isolated soon and just store it over a bunch of bisulfite... my interest is gaining in other projects right now. (especially finishing the write up of the peracetic method in DCM as I hasn't done enough testing with asarone and the peracetic and never given a formal write up... and also polishing up a cold water extract on codeine that happens to also remove most of the caffeine... plus changes to the methyl man document... etc etc)
Chromic
(Hive Addict)
06-28-02 20:57
No 326559
Results
Run down of the results happened:
1. added 3/4 volume of water to pipe cement
2. filtered with cotton, using rubber gloves squeezed out rubber in the cotton.
3. saturate the aqueous extract with salt
4. took off the top organic phase
5. add ~1/3 volume of sat bisulfite sol'n & stir slowly overnight (forms a separate layer)
6. fractionally distill the solution that should now contain the bisulfite adduct (insulate column, go slow). collect between 64-68C. (true bp=66C)
7. check density of distillate, 0.86 (true density=0.888)
8. stored with a bit of sat bisulfite sol'n until use (two separate layers form)
I seemed to have recovered about 30% of volume of the pipe cement as THF.
Chromic
(Hive Addict)
06-28-02 23:51
No 326596
Verifying that this is THF
Going close to the ratios in Post No 326569, I took 5ml 10.8% bleach (5.7g, 8.3mmol, 1.9 eq) and added 0.35ml THF (0.32g, 4.4mmol, 1 eq). I wanted to use an excess of THF to judge the completion of the reaction on the disappearance of chlorine.
Fearlessly, I added all 0.35ml of THF at once. Nothing happened. Allowed it to sit... ahh, it's getting warm. Then it starts to cool about 10 mins later. The solution is cloudy and smells like chloroform. There are small droplets of an organic phase at the bottom of the test tube.
I tested the sol'n for chlorine by adding a drop of the sol'n to phenolphtalein. It went pink (indicating basic conditions) and stayed pink (no chlorine).
Does THF smell like acetone? What tests can I do to verify that what I have is actually THF?
Chromic
(Hive Addict)
06-29-02 01:30
No 326643
Wait a minute...
(takes ten steps back) wait a minute... does anyone have any reason to believe that hypochlorite can oxidize THF to GBL in any other conditions than acetonitrile/AcOH? (Post No 3958)
It appears to me that THF is undergoing a haloform reaction... which is mighty useless to me.
Chromic
(Hive Addict)
06-29-02 02:52
No 326667
<joking>
I'm out of ideas. Maybe I'll just drink it as is, my metabolic pathways will take care of turning the THF into GHB, just as they turn GBL into GHB ever so conveniently...
</joking>
Antibody2
(Rehabilitated)
06-29-02 04:00
No 326690
What tests can I do to verify that what I have is ...
What tests can I do to verify that what I have is actually THF? aren't ethers supposed to explode when you add some H2O2?
sorry, you were talking to yourself dude
SpicyBrown
(Hive Bee)
07-03-02 21:50
No 328425
THF stinks!
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Does THF smell like acetone? What tests can I do to verify that what I have is actually THF?
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No, THF and Acetone smell pretty different from each other. Don't quite know how to describe the THF smell, except maybe along the lines of a sickly Diethyl Ether-like scent. It REALLY stinks in SWIM's opinion.. If you get a big enough whiff (Not recommended, of course) you can taste the shit in the back of your throat, nasty indeed.
SpicyBrown
Chromic
(Hive Addict)
07-03-02 22:03
No 328431
Ahh...
This stuff smells like a nasty version of acetone, maybe a bit like diethyl ether... but the smell is not as heavy or as prevalent. Ether stinks up the entire lab when it's used, this stuff doesn't seem so bad. I'm completely convinced now, that THF can't be made by aqueous oxidation using hypochlorite. I believe it can happen using acetic acid and acetonitrile... but I really doubt Cheapskate's THF -> GBL thread.
I too got something salty from the rxn, but I can say, without a doubt, that it was salt. I should add some GBL and hypochlorite to see if it forms a chlorinated layer as well, I've got little doubt that it's easily chlorinated.
weedar
(Hive Bee)
07-04-02 00:42
No 328476
Oh no!
Is this the end of theoretic OTC GHB?
(at least for now?)
Weedar
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Weedar contains 2,4-D dimethylamine salt,apparently
Osmium
(Stoni's sexual toy)
07-04-02 07:43
No 328598
I think people should concentrate on the MBrO3 ...
I think people should concentrate on the MBrO3 oxidation of THF. Once that reaction is completely understood and gives consistent yields the bleach version will work much better.
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I'm not fat just horizontally disproportionate.
riobard
(Hive Bee)
07-04-02 08:05
No 328605
I agree with Chromic on the Cheapskate write-up
The cheapskate write-up is nowhere as simple as it reads. After swim's toying with batch sizes, parameters, cooling methods, and the all too famous billowing white solids that can't be vac filtered (without special fritted disks or what the fuck ever else one might use besides qualitative grade filter paper), the two of us can only conclude that we should have saved the ACS THF for lithium aluminum hydride reductions like for 2-cb.
Aqueous methods are wasted time. If i see pool shock again before i die it will be too soon.
I'd put a little more faith in that whole procedure if someone could give us a formal write-up INCLUDING A BIOASSAY of the final product. If I'm wrong about what I did, I'd surely welcome a correct path.
Cheapskate, I mean no disrespect. Your contribution in the OTC quaalude synth was, and still is, awesome.
Chromic
(Hive Addict)
07-04-02 18:13
No 328725
Sounds good
Sounds good, but I'm not sure how many people have access to OTC access to BrO3 (not me). KBr and H2O2, OTOH, are easier to get a hold of. Is there any way to oxidize KBr to KBrO3 using H2O2?
Osmium
(Stoni's sexual toy)
07-04-02 18:27
No 328728
UTFSE for 'bromate', this has been discussed ad ...
UTFSE for 'bromate', this has been discussed ad nauseum.
KBr can be used to make Br2, which is the active ingredient in the bromate oxidation.
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I'm not fat just horizontally disproportionate.
Chromic
(Hive Addict)
07-04-02 23:50
No 328826
Let me repeat...
How do I do this? Would dripping H2O2 into a solution of KBr in water (since bromine is the catalyst, and it could be recycled, this could likely be reduce a bit) with THF and H2SO4, be a smart idea?
Can you give me a balanced set of equations so I can figure out the stoichiometry (ie how many Br2 is required per THF) and an idea of the excess (5%? 10%?) to use so that I could put together a method? Sorry for not using the search engine, but you could have brought me up to speed in half a second.
Rhodium
(Chief Bee)
07-05-02 05:00
No 328890
Equations
All the reaction equations are actually present in the original paper we discussed a few months ago: http://www.rhodium.ws/pdf/thf2gbl.pdf - not too common in journal articles nowadays, but in this case they were all there.
supernegro
December 29th, 2004, 02:27 PM
Wow! I'm going back along way here, replying to this post, but I found a glue at the home depot in the plumbing section, that was labeled as sheet PVC glue. It contained on the ingredient list THF and polyester resin (in that order). If you can find it, I'm thinking it would be easier to separate than the common MEK, hexanone, acetone, etc type.
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