Ionic Chemist
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Alternative routes, recycling of PET #2 (Aramid Products)
In the first thread (http://www.sciencemadness.org/talk/viewthread.php?tid=18270#...) I was attempting to recycle PET from plastic bottles by first breaking it down
into its original monomers, ethylene glycol and terephthalic acid; then polymerizing those monomers to again yield PET, as a bit of research into
polymer construction. However, I still have had no success in that area of research, so I thought of approaching this polymer problem from a different
angle. Instead of trying to synthesize a polyester I've decided to produce a polyaramid from PET. The procedure is essentially the same as the
synthesis of nylon shown by mabakken in his video (http://www.youtube.com/watch?v=yFEHKRdXb9Y) mixed a bit theoretically with the synthesis of Kevlar from Wikipedia (http://en.wikipedia.org/wiki/Kevlar).
Basically I am trying to synthesize a polymer by interphase polycondesation of the monmers, dissolved in an aqueous and an organic phase. So this is
where things start to get a bit complicated. The monomer which will be in the aqueous phase is one derived from PET and it is called "disodium
[4-(azanidylcarbonyl)-3-nitrophenyl]methanaminide" or simply put the disodium salt of the organic compound 2-nitrobenzene-1,4-dicarboxamide.
Meanwhile the acyl chloride, which will be in the organic phase, is a derivative of tartaric acid and is 2,3-dichlorobutanedioyl dichloride. This is
because if a polymer were to be formed I would essentially have a scaffold on which to freely attach other chemical groups by replacing the chlorine
atoms. So if everything were to go as planned then I would get a type of poly(chloroalkyl-nitroaramid) plastic. Now I still have a few question I need
assistance pertaining to before I can try to attempt creating any sort of polymer.
Chlorination of tartaric acid for the prouction of 2,3-dichlorobutanedioic acid.
Since tartaric acid is a "two-fold" alpha hydroxy acid and I won't be able to chlorinate the carboxyl groups without first removing the hydroxyl
groups. Is there any way to first chlorinate the alkyl chain by replacing the OH groups? I was thinking since the hydroxyl groups were on secondary
carbons that a simple heating with conc. hydrochloric acid and zinc chloride would be able to replace the hydroxyl groups with chlorine atoms is this
plausible?
Preparation of thionyl chloride for production of acyl chloride.
I have a solution of sulfur dichloride in chloroform. Is it possible to, or should I say safe to oxidize the sulfur dichloride dissolved in
chloroform, using sulfur trioxide as the oxidant? I am wondering if the SO3 will somehow oxidize the chloroform to phosgene. Or should I
just remove the CHCl3 beforehand then oxidize the SCl2.
Thank You......
"Discoveries are not made by idly sitting around and hoping something interesting might happen; they are made
by getting out there and doing something to push the results and odds in your favour." "Chemistry always works... just not always in the way you
want."
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wireshark
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Can't you just use PCl5? Easier to make than thionyl chloride.
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Ionic Chemist
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I wish but phosphorus derivatives, not to mention even phosphorus itself, are very hard to get down here.
Chemical suppliers usually sell to universities and high schools so I just have to make due with what I have. It's only at the rare chance that I can
ask someone to purchase a few items for me. I would prefer to use thionyl chloride because the byproducts are in the gaseous phase unlike PCl5.
Is there any easy way to synthesize phosphorus itself because with proper precautions in place I could synthesize some and chlorinate it later on. Oh!
Do you know of any processes that could be used to halogenate alpha-hydroxy acids?
"Discoveries are not made by idly sitting around and hoping something interesting might happen; they are made
by getting out there and doing something to push the results and odds in your favour." "Chemistry always works... just not always in the way you
want."
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killer_lapin
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If you microwave the PETE with the diaminobenzene, in ethylene glycol it would probably trans-esterificate to the aramide.
Attachment: 1-s2.0-S0040403999012095-main.pdf (209kB)
This file has been downloaded 2354 times
the diaminobenzene can be made by the hoffman degradation of the condensation product of terephthalic acid and ammonia.
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Ionic Chemist
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I would need more control in the RxN
@killer_lapin - I was thinking more of a controllable process. If I did microwave the PETE with the diaminobenzene and it somehow worked to produce a
polymer, I have no doubt that it would be in the form of an amorphous mass. I was hoping more along the lines of a process that would yield a threaded
fibrous material that could be better studied microscopically.
Note: I've produced a good quantity of terephthalamide before by leaving PETE bottles containing concentrated aqueous ammonia out in the sun for about
3 weeks at a time (ammonolysis of PETE seems to work best when exposed to sunlight). I've actually been doing some research on it and that's what has
lead me to this polymer research. I've also tried Hoffman Degradation of the terephthalamide and since it is insoluble in water the process was with
some solubility issues, which prompted me to try to produce a derivative that was soluble in water, the disodium
[4-(azanidylcarbonyl)-3-nitrophenyl]methanaminide. If anyone would like, I could post the lab of that synthesis.
But does anyone know a good way to halogenate alpha-hydroxyl acids, specifically replacing the hydroxyl group with a halogen group?
"Discoveries are not made by idly sitting around and hoping something interesting might happen; they are made
by getting out there and doing something to push the results and odds in your favour." "Chemistry always works... just not always in the way you
want."
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killer_lapin
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I'm not sure if the synthesis you're proposing for the alpha-beta-dichloroacid would be possible, or at least easy. Maybe a different approche like
the direct halogenation of fumaric acid, wich is a food additive so aquirable, would be better. But I suppose you have tartaric acid on hand and would
like to use it.
To come back on the thionyl chloride, you don't need SO3, you can performe the oxidation with SO2 and Cl2 bubbling in the SCl2 solution.
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Ionic Chemist
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Ester Formation Instead?
@killer_lapin - I thought about it and a possible procedure came to mind. I was thinking, what if I formed an ester out of the tartaric acid, then
chlorinated the produced diester. Afterwards, acid hydrolysis should be able to produce the dichloroacid derivative. Then simply producing the acyl
chloride using SOCl2 wont be much of a problem.
Proposed procedure:-
Convert the tartaric acid to its disodium salt and dehydrating the salt to its anhydrous form.
Produce the ester by reacting it with an alkyl halide in an appropriate solvent, then purifying the ester.
React the ester with a concentrated solution of hydrochloric acid and zinc chloride to produce the dichloro diester derivative.
Using acid hydrolysis to break down the ester, and distilling the volatile alcohol to drive the reaction forward.
Conversion of the dichloro acid to the dichloro acyl chloride by chlorination with an appropriate chlorinating agent.
So do you think this reaction could indeed be possible?
Thank You......
"Discoveries are not made by idly sitting around and hoping something interesting might happen; they are made
by getting out there and doing something to push the results and odds in your favour." "Chemistry always works... just not always in the way you
want."
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killer_lapin
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I don't think it can work this way because to convert the OH's group into Cl you're producing water, in a strongly acidic condition. So the esters
would be cleaved or partialy cleaved. But i just tought of that, we are thinking to far, the OH's can be converted to Cl with SOCl2 so if you treat
the pure tartaric acid with 4 equivalent of SOCl2 you should be able directy produce the final dichloro acyl chloride.
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Ionic Chemist
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Minor oversight
Sorry the third step was a minor oversight. I was thinking to react the ester with SOCl2 to yield the dichloro diester derivative.
My problem though with the simple addition of the SOCl2 is that this reaction has to be very controlled. This is especially true when the
acid is being converted to the acyl chloride, any excess unconverted acid that is present will react to form a polymeric ester. So I can't really see
the production the dichloro acyl chloride with the starting reactant being the tartaric acid. Unless the SOCl2 will preferentially react
with the hydroxyl group first then the carboxyl group afterwards but I am not sure if that ever happens.
Thank You......
"Discoveries are not made by idly sitting around and hoping something interesting might happen; they are made
by getting out there and doing something to push the results and odds in your favour." "Chemistry always works... just not always in the way you
want."
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killer_lapin
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Maybe you can form the dimethyl ester than convert the hydroxyl group to Cl. After purification, cleave the dimethyl ester with lithium chloride and
the react the dichloro acid with SOCl2 to form the acyl chloride. With this way you shouln'd have polymerisation.
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