Illegal Parkinson
Hazard to Self
Posts: 75
Registered: 2-10-2005
Member Is Offline
Mood: No Mood
|
|
BuLi + C2H2 -> BuH + LiCCH
Hello, i'm not very good with calculators.
I understand that pKa Butane ~ 50 whereas acetylene ~25.
In reaction BuLi + HCCH -> BuH + LiCCH
what do pKa numbers actually mean exactly?
How many time more strongly acidic are ethyne protons relative to butane (sp v sp3)?
Based on numbers it looks like two times the amount but it is log scale etc i forgot it.
|
|
|
clearly_not_atara
International Hazard
Posts: 2694
Registered: 3-11-2013
Member Is Offline
Mood: Big
|
|
It's logarithmic: a difference of 25 means that acetylene is 10^25 = 10000000000000000000000000 times as acidic as butane. However since n-BuLi has
some covalent character and the reaction occurs in a nonpolar solvent the effect isn't quite as dramatic.
|
|
|
Nicodem
|
Thread Moved
25-5-2015 at 06:57 |
![[*]](images/xpblue/default_icon.gif){kind=icon}
