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Author: Subject: Polystyrene (styrofoam) depolymerization to styrene?
Protium
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[*] posted on 11-1-2005 at 23:52
Polystyrene (styrofoam) depolymerization to styrene?


Polystyrene (styrofoam) depolymerization to styrene?

Does anybody know?

Can one simply dissolve styrofoam cups in a solvent to obtain styrene?




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Organikum
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[*] posted on 12-1-2005 at 00:43


No.

Thermal depolymerisation of PS yields crude styrene, dry distillation under exclusion of air.
Styrene is to 50% in polyester resin and often OTC in pure form.
Look at your automobile supply house for this.

/ORG




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[*] posted on 12-1-2005 at 17:14


I've also found 60% styrene available as "resin" at my local hardware store. Along side of it they sell 70% MEKP as a polymerisation catalyst.



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[*] posted on 12-1-2005 at 18:18


What would be a good method of extracting, recrystallizing or otherwise purifying from these resins? What would be ideal solvents?

Organikum mentioned that styrene could be distilled under exclusion of air. Would this just rewuire a strong vacuum or could one fill distillation apparatus with easily generated CO2?

Also, while distilling, upon reondensation would styrene be in a liquid or solid form that would plug up distillation apparatus?




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[*] posted on 12-1-2005 at 19:21


i thought that dissolving polystyrene in an organic solvent, say acetone, would monomerize it



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[*] posted on 13-1-2005 at 14:30


Why?
It usually takes rather more than that to break a carbon-carbon bond.
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[*] posted on 15-1-2005 at 20:39


Here's something from the Hive I copied with some numbers I added.. Am ready to do this and am looking for someone who already has to correspond with.


The chinese patent says: Bookmark Reply

Roughly translated:

In a reaction vessel was placed:

Styrene 21.7 g 104.15gm = 210mm bp145.2, 33.6@10mm mp-30,6 d.906 1mole or 1g

Sulfur S8 37.6 g 256.48gm = 150mm 714mm 1.73g

Ammonia 50 ml 17.03gm D.91 25% = 11.38g 670mm 3.19m .52g

Ethanol 30 ml 46.07gm d.81 96% = 23.33g 510mm 2.43m 1.07g

Under stirring and heated at 93-95 C for 3-4 hours. Fluids were evaporated from the mixture, it was allowed to cool, and extracted 3 times with 500 ml hot water. The decolorized solution after standing yielded 26.7 g (97%) white sheets having MP of 157-158 C and BP of 280-290. (Phenylacetamide C8H9NO)

100 g of the above phenylacetonitrile and 80 ml HCl were added to 150 ml water and refluxed for 2-3 hours. After cooling to room temp, a precipitate formed and was filtered and recrystallized from 1:2 ethanol/water to yield 84 g (84%) of shining white crystals. (Phenylacetic acid C8H8O2)

If desired, I can try to translate the rest of the patent.

EDIT: Guys, it looks like they're depolymerizing polystyrene to get their styrene. Could this mean meth from styrofoam?

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Catching a buzz @ the Hive

Ammonia % Bookmark Reply



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They use aqueous ammonia ? percentage ? and ethanol in 95% ?




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They don't say. I guess that's part of the proprietary secret. The ammonia is aqueous, percentage unknown, and I would imagine that a little water in the alcohol wouldn't matter, seeing as how the ammonia is dissolved in water.

Perhaps from stoichiometry it could bee guestimated. I would imagine it would be one of the standard percentages, like 10 or 28 %. My money's on 7 or 10%.

More of the patent:

Preparation of styrene:

A distillation setup was assembled. 100 g powdered scrap polystyrene was added and heated to 340 C or higher. Distillate over 340 C was collected and assumed to be styrene. Still, color was rather crimson, and impure. The impure product was mixed uniformly with 5% by volume sulfuric acid and let stand for 3h to remove impurities, then rinsed 3 times with brine, dried with anhydrous sodium sulfate, added antipolymerization additives. The portion boiling at 145-146 C was collected to yield 89 g (89%) styrene.



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