00:01
This is the answer to chapter 31, problem number eight from the smith organic chemistry textbook.
00:09
And this problem asks us to draw a stepwise mechanism for the conversion of acrylonitriol to polyacrylonitriol, using butyl lithium as our initiator and carbon dioxide as the electrophile to terminate this chain reaction.
00:25
And so we should remember that these anionic polymerizations are going to take.
00:31
Place in three parts so there's an initiation step a propagation step and a termination step so i'm going to abbreviate the initiation step with i so starting with the initiation step we have our butyl lithium oof okay so butyl lithium is going to begin by attacking our first monomer here so acrylo -nightrial right okay so that's the first step the initiation step and as a result of this initiation step the molecule that we actually end up with will be this i do apologize i'm having some lag issues so i i don't know if it's showing up for anyone watching as slowly as it's showing up on my screen, but that's why it's taking me just a little bit to write these.
02:30
Hopefully that will go away as the problem progresses.
02:34
Okay.
02:35
So what we end up with is the butel group having added to the acrylo nitrile.
02:50
There we go.
03:03
And we have our lithium cation.
03:10
Okay.
03:11
And so we now have an anion, a negative charge on that carbon.
03:17
And as i said, the lithium cation.
03:19
And so we've made our activated species here, our initiated species.
03:25
So that's the entire initiation step.
03:29
So next, we're going to have our propagation step.
03:33
So we'll call that p.
03:37
And the propagation step is going to consist of this activated species that we made in the initiation step.
04:09
Okay.
04:09
So here is our an ion.
04:14
Again, this is an anionic polymerization.
04:17
So obviously an anion is going to be jesus.
04:22
Okay.
04:25
Sorry.
04:27
There we go.
04:27
Right, so obviously this is an anionic polymerization.
04:33
So an anion is going to be key to that.
04:37
So our activated species will go ahead and attack another monomer of acrylonitriol.
04:54
So like this.
05:08
So the anion attacks there.
05:13
The electrons of this double bond will shift to that carbons.
05:17
And what we end up with here is now a dimer.
06:02
Oh, man, not again.
06:07
I apologize.
06:08
I'm not certain.
06:10
What's wrong with my tablet here? okay, so there we go...