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pKa's of Inorganic and Oxo-AcidsSubstrate H2O H3O+ H2S HBr HCl HF HOCl HClO4 HCN HN3 HSCN H2SO3 H2SO4 H3PO4 HNO3 HNO2 H2CrO4 CH3SO3H CF3SO3H NH4Cl B(OH)3 HOOH pKa H2O (DMSO) 15.7 -1.7 7.00 -9.00 (0.9) -8.0 3.17 7.5 -10 9.4 4.72 4.00 1.9, 7.21 -3.0, 1.99 2.12, 7.21, 12.32 -1.3 3.29 -0.98, 6.50 -2.6 -14 9.24 9.23 11.6 (1.6) (0.3)
R OH
Chem 206
Substrate pKa H2O (DMSO)
Substrate
O X OH
pKa
H2O (DMSO)
Substrate
pKa H2O (DMSO)
INORGANIC ACIDS (32)
CARBOXYLIC ACIDS HOH 4.76 (12.3) 1.68 2.66 2.86 2.86 3.12 1.29 0.65 -0.25 3.77 3.6, 10.3 4.2 (11.1) 2.17 2.45 3.44 2.94 3.83 3.99
Ph O Ph N O H N Me Ph
ALCOHOLS 15.7 15.5 16.5 17.0 24.0 12.5 9.3 9.95 8.4 7.1 10.2 (10.8) (19.1) (17.1) (23.5) (18.2) (18.0) (31.2) (27.9) (29.3) (29.4)
PROTONATED SPECIES
O Ph N+
+
(1.8) (15)
(12.9) (7.9)
X= CH3 CH2NO2 CH2F CH2Cl CH2Br CH2I CHCl2 CCl3 CF3 H HO C6H5 o-O2NC6H4
MeOH i-PrOH
-12.4
OH
OH
t-BuOH c-hex3COH
CF3CH2OH (CF3)2CHOH C6H5OH
-7.8
Ph
+
OH OH CH3 H
Ph
-6.2
Ph
O+ H
-6.5
Me
m-O2NC6H4OH p-O2NC6H4OH p-OMeC6H4OH
2-napthol
Me
O+
-3.8
Me
O+ H H Me O+
+
-2.05 -2.2 -1.8
m-O2NC6H4 p-O2NC6H4 o-ClC6H4 m-ClC6H4 p-ClC6H4
OXIMES & HYDROXAMIC ACIDS
N OH
H
OH S Me
11.3 (20.1) 8.88 (13.7) (NH) (18.5)
Me
OH
N+ OH Me Me N Me OH
0.79
(+1.63)
o-(CH3)3N+C6H4 1.37 p-(CH3)3N+C6H4 3.43 p-OMeC6H4
O
Ph
OH
(+5.55)
4.47
PEROXIDES
O O S O Ph S OH
SULFINIC & SULFONIC ACIDS -2.6 2.1
OH
R= H trans-CO2H
4.25 3.02, 4.38 1.92, 6.23
MeOOH CH3CO3H
11.5 8.2
Me
cis-CO2H
*Values <0 for H2O and DMSO, and values >14 for water and >35 for DMSO were extrapolated using various methods. For a comprehensive compilation of Bordwell pKa data see: http://www.chem.wisc.edu/areas/reich/pkatable/index.htm
pKa Table.1 11/4/05 1:43 PM
D.H. Ripin, D.A. Evans
Substrate pKa H2O (DMSO) Substrate pKa
pKa's of Nitrogen Acids
H2O (DMSO) Substrate
O NH O
Chem 206 pKa H2O (DMSO) Substrate pKa H2O (DMSO)
PROTONATED NITROGEN N+H4 EtN+H
3
AMINES HN3 4.7 (7.9) NH3 (41) 38 i-Pr2NH (36 THF))