Organic Chemistry Acid-Base Extraction Lab Summary (prelab)

mixture of 3 compounds ,
all dissolved in diethyl ether

: 0:

OH
H
-




benzoic acid 2-naphthol naphthalene
PKa :
4 2 . PKa = 9 5
.
no PKa (no acidic Proton)
stronger acid weaker acid
weak conj . base strong conj . base


how do we separate mixtures ?
exploit differences in acid-base chemistry
we want to isolate our 3 compounds


what differentiates these 3?

functional groups dictates reactivity
:
O
:




acid
Will be on
carboxylic
midterm 1
H
-




MostImportant Functional Groups :



alkane
main ideas for lab
alke ne

benzene ring
amine 1 .
acid-base chemistry
alcono
alkyl halide .
2 solubility differences
carboxylic acid (intermolecular forces)

, IDEA 1 :
Bronsted-Lowry acids +
bases

emphasis on Protons (H ) +




acids :
Proton donors


bases :
Proton acceptors


HCl T
HzO &
H30" +
C1-
acid base conj . acid conj . base


all molecules can sometimes be an acid or

a base context dependent

Stability favored

strong acids have weak conj · bases
strong bases have weak conj . acids


pka assumes that the solvent is water .
water PKa is different than ethanol PKa
·

the lower the pKa ,
the stronger the
stronger the acid
however stability
·
is favored. therefore
, ,



the weaker acid with a higher pha will
be favored .




HA"
+

B HB
-
A-
-




+ +
=



PKa = 6 PKa : 9