Keras
National Hazard
Posts: 933
Registered: 20-8-2018
Location: (48, 2)
Member Is Offline
|
|
Recovery of styrene monomer from polystyrene
Folks,
I have (or rather: used to have) a one litre bottle of styrene, that I left in store somewhere. When I turned back to it, all the styrene had
polymerised, so it’s now a bottle full of white polystyrene.
If I wanted to recover the monomer from its present form, what should I do? I read here that heating polystyrene at 400 °C over a MgO bed can led to around 70% styrene recovery. By chance, any other method you'd know that'd
require less heat, maybe ?
Thanks.
|
|
|
njl
National Hazard
Posts: 609
Registered: 26-11-2019
Location: under the sycamore tree
Member Is Offline
Mood: ambivalent
|
|
The gist of polystyrene to styrene monomer is mostly thermal cracking as far as I know. There are some catalysts like metal oxides (MgO) that can
either increase recovery or lower the reaction temperature, but you will still have to use high heat. UC235 has a video on polystyrene cracking on
youtube.
Reflux condenser?? I barely know her!
|
|
|
draculic acid69
International Hazard
Posts: 1371
Registered: 2-8-2018
Member Is Offline
|
|
I'm just guessing but 70% seems rather on the low side. Doesn't the uc235 video
Show a much higher yeild using no catalyst?
|
|
|
zed
International Hazard
Posts: 2284
Registered: 6-9-2008
Location: Great State of Jefferson, City of Portland
Member Is Offline
Mood: Semi-repentant Sith Lord
|
|
Yields via pyrolysis are pretty good.
For some unknown reason, this video isn't starting at the beginning.
https://www.youtube.com/watch?v=6tEs7P6UUVQ
[Edited on 28-4-2021 by zed]
|
|
|
unionised
International Hazard
Posts: 5128
Registered: 1-11-2003
Location: UK
Member Is Offline
Mood: No Mood
|
|
It used to be a classic school demo.
Just heating the stuff will give you styrene.
But, unless you have some hydroquinone or something to use as a polymerisation inhibitor, it will revert to a polymer again.
Also works with PMMA
|
|
|
Keras
National Hazard
Posts: 933
Registered: 20-8-2018
Location: (48, 2)
Member Is Offline
|
|
Quote: Originally posted by unionised  | It used to be a classic school demo.
Just heating the stuff will give you styrene.
But, unless you have some hydroquinone or something to use as a polymerisation inhibitor, it will revert to a polymer again.
Also works with PMMA
|
Oh, I have 125 g of hydroquinone I didn't know what to do with. Thanks a bunch of suggesting this!
|
|
|
unionised
International Hazard
Posts: 5128
Registered: 1-11-2003
Location: UK
Member Is Offline
Mood: No Mood
|
|
I think that's roughly enough for (literally) a ton of styrene.
|
|
|
njl
National Hazard
Posts: 609
Registered: 26-11-2019
Location: under the sycamore tree
Member Is Offline
Mood: ambivalent
|
|
Yielding methyl methacrylate?
Reflux condenser?? I barely know her!
|
|
|
zed
International Hazard
Posts: 2284
Registered: 6-9-2008
Location: Great State of Jefferson, City of Portland
Member Is Offline
Mood: Semi-repentant Sith Lord
|
|
Yup! I think I might have posted a procedure...once upon a time.
[Edited on 29-4-2021 by zed]
|
|
|
njl
National Hazard
Posts: 609
Registered: 26-11-2019
Location: under the sycamore tree
Member Is Offline
Mood: ambivalent
|
|
Off topic to this thread, but what did you end up doing with it?
Reflux condenser?? I barely know her!
|
|
|
Keras
National Hazard
Posts: 933
Registered: 20-8-2018
Location: (48, 2)
Member Is Offline
|
|
Had I known (or guessed, rather) that before, I would've added a few mg of it directly to my styrene bottle in the first place.
Talk about late epiphanies… :p
|
|
|
Swinfi2
Hazard to Others
Posts: 131
Registered: 19-2-2018
Location: England
Member Is Offline
Mood: Catalytic
|
|
I've done this without any catalyst, bloody stinks and it broke my RBF on cooling. Didn't have any inhibitors to keep the product but it worked well
enough with minimal thought put into it.
That said if the flask didn't break I probably would never have got it clean from all the charing.
|
|
|
Keras
National Hazard
Posts: 933
Registered: 20-8-2018
Location: (48, 2)
Member Is Offline
|
|
Any idea why it broke?
|
|
|
![[*]](images/xpblue/default_icon.gif){kind=icon}
