QO323
Química Orgânica I(Engenharia Química)
MARCOS N. EBERLIN
Acidez e BasicidadeAcidez e Basicidade
AcidezOH
< R OH
O
< HClR-OH <R-H <
pKa ~ 50
R-NH2
pKa ~ 37
<
pKa ~ 16pKa ~ 50
pKa ~ 10pKa ~ 4
pKa ~ -7pKa ~ 37
48p =
+
aK
δ-δ
3 H
CH
38p =
+
aK
δ-δ
2 H
NH
15,7p =
+
aK
δ-δ
H
OH
3,2p =
+
aK
δ-δ
H
F
Aumento da Acidez
Differences in acid strengths between carboxylic acids,
phenols and alcohols The factors to consider
Two of the factors which influence the ionisation of an acid
are:
1. the strength of the bond being broken,
2. the stability of the ions being formed.
pKa
HCOOH 3.75
CH3COOH 4.76
CH3CH2COOH 4.87
CH CH CH COOH 4.82CH3CH2CH2COOH 4.82
pKa
CH2FCOOH 2.66
CH2ClCOOH 2.86
CH2BrCOOH 2.90
CH2ICOOH 3.17