Sciencemadness Discussion Board

Polymethylpiperazine? Proposed synthesis for a polymer.

CaptainMolo - 4-1-2018 at 17:33

Okay so first off, I'm not the most well versed chemist out there, so please forgive me if I make some naive blunders. That being said, I had an interesting idea earlier this evening, and I wanted to bounce it off of you guys before wasting reagents.

So I was thinking I could react Dichoromethane with Piperazine Dihydrochloride by using Sodium Hydroxide as the condensation initiator (not a catalyst, because it would take part in the reaction). My thinking is that the chlorine/hydrochlorides would be attracted to the hydroxide, and form sodium chloride and the loss of those moieties from the other two molecules might generate a favorable environment for the amine groups in Piperazine to bond with the now free methyl group in the solution.

So I was thinking that the chain would end up being linear, with repeated alternating methyl and Piperazine groups.

Now I haven't tried this, and I also haven't done much searching around yet on the internet to see if this has been tried before or if this polymer is already known and studied.

Does anyone see any immediate and obvious error in my reasoning that would suggest that this would be a waste of time to try? The precursors are cheap, so I'm not particularly worried if I end up having to do this many times.

Also in a condensation like this, will the scale of the reaction be much of a factor like it can be with things like aldol condensations? This one seems like it would produce a pretty stable product, because nitrogen seems pretty happy to stay stable with three bonds when it's in the form of ammonia.

Anyway, any insight or input would be greatly appreciated.
Thank you for taking the time to read this.

unionised - 5-1-2018 at 09:59

I guess it would work.
Similar polymers are known.

I suspect there may be problems due to steric hindrance.

SWIM - 5-1-2018 at 10:19

I would of thought the NaOH might hydrolyze the DCM to formaldehyde and you'd end up methylating your piperazine.

clearly_not_atara - 5-1-2018 at 11:11

Wouldn't phosgene or terephthaloyl chloride make a tougher polymer?

Sigmatropic - 5-1-2018 at 12:28

NaOH induced hydrolysis of DCM or decomposition of (hemi)aminals of piperazine would lead to formaldehyde being present. I currently lack the motivation(it being Friday night and all) to do a (literature) search, but I encourage looking into resins from formaldehyde and piperazines or other similar secondary diamines.

CaptainMolo - 5-1-2018 at 15:34

Thank you all for your input so far, I will definitely do more research into the possibilities you all suggested. As for the properties of this proposed polymer, I can only guess that it would probably have a low melting point, much like polycaprolactone, but that's just a guess because I figure that having a heterocycle is probably similar to a cyclic ester in it's effect on melting points. That's of course based on nothing other than the two both have more than just carbon in the ring, and it's probably way off base.

Nicodem - 6-1-2018 at 02:38

It would be "poly(methylenepiperazine)" (there are no methyl groups in your proposed product).
And you would want to use formaldehyde, not dichloromethane.
And the preferred product would not necessarily be a polymer, as the polymer would be anything but stable (very sensitive to hydrolysis in acidic and neutral; unstable to heat). The monomer, 1,​4-​diazabicyclo[2.2.1]​heptane (CAS: 279-63-0), is a known compound, though I can't find any reference to its preparation.

Polymeric Mannich bases between formaldehyde, piperazine and suitable fenols (or other nucleophilic enough substrates) are known (google it).

Please open threads not using any references only in the Beginnings section.

CaptainMolo - 6-1-2018 at 06:40

Noted. I apologize for the poorly researched post. I got excited about the reaction because it made sense in my mind, I wasn’t aware of the convention on the org section. I’ll look up the Mannich bases thing.