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Topic: Polymerization of phenoxy to form polyphenyl ether.  (Read 3626 times)

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Offline Varlam

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Polymerization of phenoxy to form polyphenyl ether.
« on: October 26, 2018, 04:59:44 PM »
This link contains the polymer, and the phenoxy is the one that is in square bracket. https://en.m.wikipedia.org/wiki/File:Polyphenyl_Ether.png

I know that phenoxy is a phenol having its hydrogen removed from its hydroxyl group.

My question is: can multiple phenoxy link to each other to form a polymer.

For example, is it possible for the oxygen of the phenoxy to share the electron of the hydrogen of another phenoxy, thus forming a slightly polar covalent bond and therefore forming an ether linkage?
« Last Edit: October 26, 2018, 06:15:36 PM by Varlam »

Offline wildfyr

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Re: Polymerization of phenoxy to form polyphenyl ether.
« Reply #1 on: October 26, 2018, 06:03:18 PM »
You're thinking of a peroxide, I think. It's not very clear.

And that would be a dimer, a polymer is many units, typically more than ten or so.

Offline Varlam

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Re: Polymerization of phenoxy to form polyphenyl ether.
« Reply #2 on: October 26, 2018, 06:13:37 PM »
You're thinking of a peroxide, I think. It's not very clear.

And that would be a dimer, a polymer is many units, typically more than ten or so.

This is the polymer that I'm talking about, and the molecule that is in the square bracket is the phenoxy(monomer) that I'm assuming.
https://en.m.wikipedia.org/wiki/File:Polyphenyl_Ether.png

Offline wildfyr

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Re: Polymerization of phenoxy to form polyphenyl ether.
« Reply #3 on: October 26, 2018, 07:01:34 PM »
Ah I understand now. This polymer is made by Ullman ether synthesis:

https://en.wikipedia.org/wiki/Polyphenyl_ether#Structure_and_synthesis

A diphenolate (deprotonated phenol) is reacted with di bromobenzene derivative in the presence of a copper catalyst at high temperatures.

The sentence that is confusing is

Quote
oxygen of the phenoxy to share the electron of the hydrogen of another phenoxy

Which is a strange and difficult to understand idea. The answer is no if I read it correctly, but its a little murky.

Offline Varlam

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Re: Polymerization of phenoxy to form polyphenyl ether.
« Reply #4 on: October 26, 2018, 11:58:42 PM »
Ah I understand now. This polymer is made by Ullman ether synthesis:

https://en.wikipedia.org/wiki/Polyphenyl_ether#Structure_and_synthesis

A diphenolate (deprotonated phenol) is reacted with di bromobenzene derivative in the presence of a copper catalyst at high temperatures.

The sentence that is confusing is

Quote
oxygen of the phenoxy to share the electron of the hydrogen of another phenoxy

Which is a strange and difficult to understand idea. The answer is no if I read it correctly, but its a little murky.

Can the monomers be dibromobenzene and phen-1,2-diol? so that in the presence of some catalyst and conditions, bromine takes the hydrogen of the hydroxyl group of the phenol to form HBr, thus two benzene rings will be linked by ether linkage.
« Last Edit: October 27, 2018, 12:16:43 AM by Varlam »

Offline wildfyr

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Re: Polymerization of phenoxy to form polyphenyl ether.
« Reply #5 on: October 27, 2018, 12:38:32 PM »
No, you need to deprotonate the phenol with a base, alcohols are very poor nucleophiles and won't be able to attack the aryl bromide.

Bromine cannot act as a base until it is displaced from the C-Br bond and becomes negatively charged bromide. Even then, it is a weak base.

Offline Varlam

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Re: Polymerization of phenoxy to form polyphenyl ether.
« Reply #6 on: October 27, 2018, 01:23:28 PM »
No, you need to deprotonate the phenol with a base, alcohols are very poor nucleophiles and won't be able to attack the aryl bromide.

Bromine cannot act as a base until it is displaced from the C-Br bond and becomes negatively charged bromide. Even then, it is a weak base.

So when you deprotonate the phenol, Oxygen will have excess amount of electrons and attack on bromine,and bromine will take that extra electon to form bromide ion? Did I get it right?

Offline wildfyr

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Re: Polymerization of phenoxy to form polyphenyl ether.
« Reply #7 on: October 27, 2018, 03:21:55 PM »
No, oxygen is using its extra lone pair to attack the aryl carbon and kicking off bromide, and bromine is getting the pair it was using to bond with the same aryl carbon.

You should look up how arrow pushing and simple nucelphilic substitution works. This is an odd case since usually aryl halides don't react in this way without serious ass kicking, but it's the same in its essentials.

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