00:01
Okay, we've got to draw a balanced chemical equation for the reduction of vanilla acetate, which has the formula c -10 -h -10 -o -4, with sodium borohydrate, sodium borohydride, which is sodium -bohydride is bh4 that's minus going to the high so essentially what's going to happen is that a hydrogen will transfer from the borohydride to the benillin acetate giving a c10 h 11 o4 minus with sodium plus and neutral b .h.
01:07
3.
01:08
This can also be shown as follows, in which we include water, which will be protonating the vanillin, in which case it would be c -10, h -10 -4, plus sodium, plus n -b -h -4, minus, plus water, going to c -10 -h -10, h -12 -0 -4.
01:45
Neutral.
01:47
That is, it gained one hydrogen from the sodium borhydride, as well as just a single proton, positively charged proton, from the water, leaving behind neutral bh3 again, as well as sodium plus, and because of the loss of proton from water, oh -h -minus.
02:08
This would be a balance, but either of these would be a valid, balanced chemical reaction or chemical equation.
02:16
Okay, now we're supposed to look at the structure of the starting material in products.
02:21
So we've got starting material, vanilla acetate.
02:47
And, oh, i made a mistake there.
02:49
My mistake.
02:50
Let me fix this really quickly.
02:53
This is an ester.
03:03
There we are.
03:04
And this is vanilla acetate.
03:07
Now when this undergoes a reduction, this aldehyde will convert to an alcohol.
03:15
That is, nabh4.
03:26
We will get, let's just make this ring in there there.
03:37
Okay, the ester is not touched.
03:40
The ether linkage is not touched.
03:42
But now this has become an alcohol.
03:46
And we are left with n -a -plus.
03:51
The water here plus oh h minus and our bh3 neutral and maybe to hammer this home we can put the charges here on the bh3 and the sodium plus so how can we tell that a reduction took place uh or that there was an oxidation reduction reaction well for one this carbon has been reduced the oxidation state of it before was higher because it had two bonds to oxygen, whereas now it has a single bond to oxygen.
04:29
So that's indicative of a reduction.
04:34
The other hint we have that an oxidation reduction took place is if we look at our borohydride turning into bh3.
04:46
It's lost its charge.
04:48
It's become oxidized.
04:49
It was bh3 minus and under oxidation, or bh4 minus, and it was oxidized, losing a bond to hydrogen to become neutral ph3.
05:01
So those are two clues that we've seen in oxidation reduction reaction.
05:05
Now finally, we've got to see an arrow -pushing mechanism for this reduction.
05:11
So we will start again with vanilla acetate hydrogen...