Polar Protic, Polar Aprotic and Non-Polar Solvents
Key Questions
-
Answer:
Non-polar solvents are non-polar molecules that can be used as solvent.
Explanation:
Non-polar solvents are any non-polar molecules that can be used as a solvent.
Example:
Hexane, pentane, heptane, etc.
Carbon tetrachloride#"C"Cl_4# .
Dr. Hayek
·
4
·
Oct 3 2015
-
Here's an example.
Let's hypothetically react
#Li^((+)) [(CH_2)_3CH_3]^((-))# (commonly#BuLi# ) with acetone. Normally,#BuLi# is a fantastic nucleophile due to lithium's lewis acid characteristics.
If you solvate
#BuLi# in the optimal amount of ethanol (commonly#EtOH# ), you have now in solution, before anything happens,#BuLi# ,#EtOH# , and acetone.Acetone:
What would most likely happen is that since
#BuLi# has such a high nucleophilicity, instead of reacting with acetone all the time, there is a good chance it would also steal a proton from#EtOH# .At that point,
#BuLi# would become butane, which is clearly nonreactive as a poor nucleophile. Then,#EtO^(-)# forms and it becomes a potential nucleophile to attack acetone (but less often, as it's a worse nucleophile).At this point, you may realize that you now have a situation where:
#BuLi# grabs a proton and loses its reactivity, allowing#EtO^(-)# to be an additional nucleophile (there's still some#BuLi# leftover)#BuLi# attacks acetone and the reaction proceeds to#EtOH# protonating the tetrahedral intermediate to form a tertiary alcohol.
The result then is a mixture of the butane,
#EtOH# , acetone, the tertiary alcohol, and the product of the mechanism where#EtO^(-)# attacks acetone. Ideally you don't want a mixture that you'd have to separate and purify later. If you got a pure product, that's what you should want.So naturally, it's a good idea, for example, to not use a protic solvent when using an anionic nucleophile, because it may actually deactivate the nucleophile.
Truong-Son N.
·
1
·
Jul 11 2015