Sciencemadness Discussion Board - preparation or proplene carbonate from plastic

preparation or proplene carbonate from plastic

symboom - 11-5-2011 at 08:22

there is this rope ive found is says its made out of polypropylene
i figure if i depolymerize the polypropylene into propylene then lead propylene gas into liquid chlorine to prevent it from escaping in the presence of moisture to form chloropropanols then dechlorinated with lime forming propylene oxide then adding dry ice to the liquid hopefully form propylene carbonate which can be used to isolate metals like potassium at room temperature from its chloride salt.

http://en.wikipedia.org/wiki/Propylene_oxide
http://en.wikipedia.org/wiki/Propylene_carbonate

[Edited on 11-5-2011 by symboom]

ScienceSquirrel - 11-5-2011 at 08:43

How are you going to convert the polypropylene in to propylene?
Heating it will give you a whole heap of shit that will contain very little propylene.
You would be better off starting from propylene glycol from your local chemist.

symboom - 11-5-2011 at 09:16

Thermal depolymerization like you said would yield very little.
i was thinking of introducing a compound to cause depolymerization. polyproplene is unusually resistant to many chemical solvents, bases and acids.
so there still but their has to be something that breaks it down to proplene.

http://www.engineeringtoolbox.com/polypropylene-pp-chemical-...

not sure which compound here will break down the polymer any suggestions.

[Edited on 11-5-2011 by symboom]

Dr.Bob - 11-5-2011 at 09:27

Propylene glycol is in Sierra (non-toxic type) antifreeze. You might be able to react it directly with a carbonyl source (CDI, phosgene, etc) to generate the cyclic carbonate.

But Propylene glycol would be the easiest to obtain starting material for almost any route, as it is used for deicer, car anti-freeze, RV water anti-freeze, etc. You could probably even form the epoxide directly from it somehow.

ScienceSquirrel - 11-5-2011 at 09:54

Even if you can find a way of making propylene in a good yield from polypropylene, it is a gas boiling at -46.6 C so it is going to be hard to handle.
Reaction of easy to come by and purify propylene glycol will always be a preferred route.
You just need a suitable carbonating agent, do not go for phosgene it is a big no no!

Random - 11-5-2011 at 12:05

propylene carbonate can be made from propylene glycol and urea by distillation if I remember correctly

ScienceSquirrel - 11-5-2011 at 12:56

It is good to try and think of new ways to make things but you have to keep cost and practicality in mind.
Propylene glycol seems to be cheaply and readily available from a lot of sources.
Home chemists can purify it quite easily and it is easy to handle and non toxic.
The sensible thing in my opinion is to research the availability of the glycol.
If we can establish that then looking at reactions that make the carbonate is the next logical step.

AndersHoveland - 11-5-2011 at 14:36

Propylene carbonate is potentially very interesting as a solvent for Finkelstein reactions, since it has the unusual ability to dissolve both ionic salts and hydrophobic compounds.

Boiling point 241.7°C
Freezing point -55°C
Dielectric constant 64.9 at 20°C
Solubility of water in propylene carbonate 8.3% at 25°C
Solubility of propylene carbonate in water 17.5% at 25°C

Here is the link to an application of the Finkelstein reaction.
http://7007983270460794965-a-1802744773732722657-s-sites.goo...

Even chlorine atoms on hydrocarbons can be substituted with any other desirable group. Although the general idea is simple, in practice the reaction is plagued with technical difficulties. An appropriate catalyst must be used to promote chlorine substitution, otherwise the reaction rate is negligible. The choice of solvent is extremely important, generally water or alcohols cannot be used because the haloalkane will react with those solvents as fast as the desired substitution will take place. But the solvent must dissolve both reactants. For example, simply mixing plain bromoform and sodium nitrite will not yield ant trinitromethane. But such a reaction could potentially be possible with propylene carbonate.

There does not exist any practical way to depolymerize propylene carbonate. As for the suggested propylene glycol route, that entails the use of extremely poisonous phosgene gas, which we would like to avoid if at all possible. One thought is perhaps trying to reflux finely powdered sodium carbonate with propylene bromide, but of course bromoalkanes give are also very toxic, with volatile fumes.

The dehydration of isopropyl alocohol by concentrated H2SO4 results in mostly propylene gas, which could then be reacted with dry chlorine gas to form propylene dichloride.

A recently developed route is the direct reaction between CO2 and propylene epoxide, using an iron ion resin, but the reaction requires extreme pressures. Edit: "BromicAcid" 's procedure using ethylene glycol and urea with ZnO catalyst is excellent. Using propylene glycol instead would no doubt form propylene carbonate.

[Edited on 12-5-2011 by AndersHoveland]

ScienceSquirrel - 12-5-2011 at 02:48

The easy way to propylene carbonate is propylene glycol and urea plus a catalyst.
Both chemicals are OTC and non toxic, the catalysts are easily prepared and you can do the reaction with a modicum of glass.

Random - 12-5-2011 at 02:59

If you need it to make alkali metals, you can also use ethylene carbonate, it works just like propylene carbonate and can be made from ethylene glycol, urea and ZnO catalyst.

Ephoton - 12-5-2011 at 03:07

this reference is in wiki under propylene carbonate.

J. Jorné and C. W. Tobias (1975), Electrodeposition of the alkali metals from propylene carbonate. Journal of Applied Electrochemistry, volume 5 issue 4, pp. 279-290. doi:10.1007/BF00608791

ThatchemistKid - 12-5-2011 at 11:29

Does anyone have a reference for the synthesis of ethylene or propylene carbonate from urea, the diol and a zinc oxide catalyst?

apparently I do not think open my eyes before I post something

here is a pretty good procedure

http://www.bromicacid.com/carbonate.htm

(is this the same bromic acid on here I assume it is?)

[Edited on 12-5-2011 by ThatchemistKid]

symboom - 13-5-2011 at 07:48

thank you ive been looking everywhere for these reactions of these type of compounds

The dehydration of isopropyl alocohol by concentrated H2SO4 results in mostly propylene gas, which could then be reacted with dry chlorine gas to form propylene dichloride.
from there how do i end up with propylene carbonate

would it be reaction of water to form liquid propylene oxide then add dry ice (co2) or baking soda to form propylene carbonate

[Edited on 13-5-2011 by symboom]

Neil - 13-5-2011 at 08:06

Why make propylene gas when you can purchase it at your hardware store? It's often sold as "Brazing fuel" and with the death of MAPP gas it's being sold as MAP-PRO and MAPP* where * = not MAPP but we want to sucker you into thinking it is.

ScienceSquirrel - 13-5-2011 at 08:31

Quote: Originally posted by symboom

Would it be reaction of water to form liquid propylene oxide then add dry ice (co2) or baking soda to form propylene carbonate

Water will not react with propylene dichloride to form propylene oxide.
Neither dry ice or baking soda will react with propylene oxide to form propylene carbonate.

ScienceSquirrel - 13-5-2011 at 08:49

You can buy propylene glycol, urea and zinc oxide from eBay and loads of other places.
You mix them together, reflux and distill, bingo you have propylene carbonate.
One step and one pot, organic chemistry does not get easier than this!
No gas chemistry, no nasties like 1, 2 dichloropropane or propylene oxide, no multistep synthesis or inventing your own reaction conditions.

symboom - 7-6-2011 at 17:33

Quote: Originally posted by ScienceSquirrel

You can buy propylene glycol, urea and zinc oxide from eBay and loads of other places.
You mix them together, reflux and distill, bingo you have propylene carbonate.
One step and one pot, organic chemistry does not get easier than this!
No gas chemistry, no nasties like 1, 2 dichloropropane or propylene oxide, no multistep synthesis or inventing your own reaction conditions.

thank you that works i will persue this instead.

ThatchemistKid - 2-9-2011 at 10:27

"You can buy propylene glycol, urea and zinc oxide from eBay and loads of other places.
You mix them together, reflux and distill, bingo you have propylene carbonate.
One step and one pot, organic chemistry does not get easier than this!
No gas chemistry, no nasties like 1, 2 dichloropropane or propylene oxide, no multistep synthesis or inventing your own reaction conditions."

from preforming this reaction with ethylene glycol to prevent
Oxazolidone ring formation the reaction has to be run under vacuum at high temperatures for several hours, it out gasses ammonia so a trap is needed if one does not wish to have any brass or copper parts in their pump be reduced to a blue goo. After distillation the reaction affords pretty low yeilds without very precise condition control, I ran the reaction 4 or 5 times earlier this summer and had very little success. (doesnt mean you guys wont have success =P)
http://en.wikipedia.org/wiki/2-Oxazolidone

Though I just read in March advanced organic chemistry edition 4 page 399 that there is a way to prepare carbonate esters from the alkyl halide and dry potassium carbonate or bicarbonate. Does anyone know more about this method or have an article on it because it would be an easily accessible inexpensive way to synthesis carbonate esters. I do not just want to assume that it is as simple as dissolving 2 eqs of Kcarb in DMSO or HMPA and adding the alkyl halide followed by heating and then distillation .

[Edited on 2-9-2011 by ThatchemistKid]