[iScience]

if i'm trying to extract an H from the secondary carbon and form a carbocation, any ideas how i could do this?



if i had this stuff in solution with a strong base, would the OH- even do anything to any of the Hydrogens? if so, how would i get it to target (extract) an H on all the secondary C's?

if the OH- does extract H's, I'm thinking that even if the tertiary H is extracted, an H from the secondary would move over and take the primary carbocation's place, leaving the carbocation eventually ending up on the secondary carbon.

[zsinger]

Do you think that would be easy to accomplish?  Do you think NaOH would do it?  Polymers are strong for a reason .
                 -Zack

[iScience]

yes, that's what i'm hearing, "polymers are strong", i know that benzenes are quite stable, but what makes the secondary H so stable that it can't even be extracted by a base heated in solution?

[zsinger]

What exactly are you trying to accomplish with this, and maybe I can help you further?

[iScience]

well, just a project for fun i want to turn polystrene back into monostryene

[orgopete]

if i'm trying to extract an H from the secondary carbon and form a carbocation, any ideas how i could do this?

if i had this stuff in solution with a strong base, would the OH- even do anything to any of the Hydrogens? if so, how would i get it to target (extract) an H on all the secondary C's?

if the OH- does extract H's, I'm thinking that even if the tertiary H is extracted, an H from the secondary would move over and take the primary carbocation's place, leaving the carbocation eventually ending up on the secondary carbon.

For the moment, let us assume NaOH did pull a proton, where would the electrons of the C-H bond remain? Secondly, you can estimate whether NaOH might abstract a proton from polystyrene by comparing the pKa's of HF, H2O, NH3, and CH4. You might expect NaOH can pull a proton from HF, but what about any of the others?

Hint, turning polystyrene back to styrene may be referred to as depolymerization. Try doing an internet search for it.

[iScience]

forgot about that... if an OH- extracts an H, the e^- would remain on the carbon, so is that why this is not likely to happen? since carboanions are very unstable?


i looked up depolymerization/ depolymerization of polystrene but nothing comprehendible at my level popped up. can you help me out some more?

[zsinger]

OH- not nearly strong enough a base to grab that proton.  Might need a super base, or something such as sodium amide.

[discodermolide]

Basic conditions will not form a cation on carbon!
Think acid.

[orgopete]

This is very much a basic question about chemistry. The proton and electrons of an unactivated CH are unlikely to react under normal conditions. This may have been inferred from the formation of halides from an unactivated alkane by free radical chemistry.

Although I agree with Disco's suggestion to use an acid, I don't think the equilibrium favors formation of a carbocation under normal conditions. That does not necessarily mean there are not or may not be any proton-electron interactions, but that if they form, the reverse reaction is favored. Therefore, if one wishes to break a C-C bond, one might use a combination including heat or light to destabilize the bond or polymer/catalyst. I am not an expert in this chemistry, but I found the polystyrene can be thermally cracked. I would think the chemistry associated with cracking would apply here. Again, as I recall, heat or heat and Lewis acids are used to crack hydrocarbons. The use of a Lewis acid would sustain Disco's suggestion the electrons may interact with an acid, though the interaction is weak, but when combined with heat are sufficient to be productive in breaking bonds.