Appendix B | Acidity Constants for Some Organic Compounds

Acidity Constants for Some Organic Compounds

Compound

 pKa
CH3SO3H -1.8
CH(NO2)3 0.1
The structure has a phenol ring. C 2, C 4, and C 6 are each bonded to a nitro group. 0.3
CCl3CO2H 0.5
CF3CO2H 0.5
CBr3CO2H 0.7
  HO2CC≡CCO2H 1.2; 2.5
HO2CCO2H 1.2; 3.7
CHCl2CO2H 1.3
CH2(NO2)CO2H 1.3
  HC≡CCO2H 1.9
(Z) HO2CCH=CHCO2H 1.9; 6.3

The structure has a benzene ring. C 1 is bonded to a carboxylic acid group. C 2 is bonded to a nitro group.

 2.4
CH3COCO2H 2.4
NCCH2CO2H 2.5
  CH3C≡CCO2H 2.6
CH2FCO2H 2.7
CH2ClCO2H 2.8
HO2CCH2CO2H 2.8; 5.6
CH2BrCO2H 2.9

The structure has a benzene ring. C 1 is bonded to a carboxylic acid group. C 2 is bonded to a chlorine atom.

 3.0
Compound pKa

The structure has a benzene ring. C 1 is bonded to a carboxylic acid group. C 2 is bonded to a hydroxyl group.

 3.0
CH2ICO2H 3.2
CHOCO2H 3.2

The structure has a benzene ring. C 1 is bonded to a carboxylic acid group. C 4 is bonded to a nitro group.

 3.4

The structure has a benzene ring. C 1 is bonded to a carboxylic acid group. C 3 and C 4 are each bonded to a nitro group.

 3.5
HSCH2CO2H 3.5; 10.2
CH2(NO2)2 3.6
CH3OCH2CO2H 3.6
CH3COCH2CO2H 3.6
HOCH2CO2H 3.7
HCO2H 3.7

The structure has a benzene ring. C 1 is bonded to a carboxylic acid group. C 3 is bonded to a chlorine atom.

 3.8

The structure has a benzene ring. C 1 is bonded to a carboxylic acid group. C 4 is bonded to a chlorine atom.

 4.0
CH2BrCH2CO2H 4.0

The structure has a phenol ring. C 2 and C 4 are each bonded to a nitro group.

 4.1

The structure has a benzene ring. C 1 is bonded to a carboxylic acid group.

 4.2
H2C=CHCO2H 4.2
HO2CCH2CH2CO2H 4.3; 5.7
HO2CCH2CH2CH2CO2H 4.3; 5.4

      The structure has a phenol ring. C 2 to C 6, each carbon is bonded to a chlorine atom.

 4.5
  H2C=CH(CH3)CO2H 4.7
CH3CO2H 4.8
CH3CH2CO2H 4.8
Compound pKa
(CH3)3CCO2H 5.0
CH3COCH2NO2 5.1

The structure has a cyclohexane ring. C 1 and C 3 are oxo groups.

 5.3
O2NCH2CO2CH3 5.8
The structure has a cyclopentane ring. C 1 has an oxo group. C 2 is bonded to an aldehyde group. 5.8

The structure has a phenol ring. C 2, C 4, and C 6 are each bonded to a chlorine atom.

 6.2

The structure has a benzene ring. C 1 is bonded to an S H group.

 6.6
HCO3H 7.1

The structure has a benzene ring. C 1 is bonded to a hydroxyl group. C 2 is bonded to a nitro group.

 7.2
(CH3)2CHNO2 7.7

  The structure has a benzene ring. C 1 is bonded to a hydroxyl group. C 2 and C 4 are each bonded to a chlorine atom.

 7.8
CH3CO3H 8.2

The structure has a benzene ring. C 1 is bonded to a hydroxyl group. C 2 is bonded to a chlorine atom.

 8.5
CH3CH2NO2 8.5

The structure has a benzene ring. C 1 is bonded to a hydroxyl group. C 4 is bonded to a trifluoromethyl group.

 8.7
CH3COCH2COCH3 9.0

The structure has a benzene ring. C 1 and C 3 are each bonded to a hydroxyl group.

 9.3; 11.1

  The structure has a benzene ring. C 1 and C 2 are each bonded to a hydroxyl group.

 9.3; 12.6
Compound pKa
The structure has a benzene ring. C 1 is bonded to a C H 2 S H group. 9.4
The structure has a benzene ring. C 1 and C 4 are each bonded to a hydroxyl group. 9.9; 11.5
The structure has a benzene ring. C 1 is bonded to a hydroxyl group. 9.9
CH3COCH2SOCH3 10.0
The structure has a benzene ring. C 1 is bonded to a hydroxyl group. C 2 is bonded to a methyl group. 10.3
CH3NO2 10.3
CH3SH 10.3
CH3COCH2CO2CH3 10.6
CH3COCHO 11.0
CH2(CN)2 11.2
CCl3CH2OH 12.2
Glucose 12.3
  (CH3)2C=NOH 12.4
CH2(CO2CH3)2 12.9
CHCl2CH2OH 12.9
CH2(OH)2 13.3
HOCH2CH(OH)CH2OH 14.1
CH2ClCH2OH 14.3
The structure has a cyclopentane ring. C 1 is double bonded to C 2. C 3 is double bonded to C 4. 15.0
The structure has a benzene ring. C 1 is bonded to a hydroxymethyl group. 15.4
CH3OH 15.5
  H2C=CHCH2OH 15.5
CH3CH2OH 16.0
CH3CH2CH2OH 16.1
CH3COCH2Br 16.1
The structure has a cyclohexane ring. C 1 is double bonded to an oxygen atom. 16.7
CH3CHO 17
Compound pKa
(CH3)2CHCHO 17
(CH3)2CHOH 17.1
(CH3)3COH 18.0
CH3COCH3 19.3
The structure has a central cyclopentane ring fused to a benzene ring by C 1 and C 2, and to another benzene ring by C 3 and C 4. 23
CH3CO2CH2CH3 25
  HC≡CH 25
CH3CN 25
CH3SO2CH3 28
(C6H5)3CH 32
(C6H5)2CH2 34
CH3SOCH3 35
NH3 36
CH3CH2NH2 36
(CH3CH2)2NH 40
The structure has a benzene ring. C 1 is bonded to a methyl group. 41
The structure of benzene: a six-membered ring with alternating single and double bonds. 43
 H2C=CH2 44
CH4 ~60

An acidity list covering more than 5000 organic compounds has been published: E.P. Serjeant and B. Dempsey (eds.), “Ionization Constants of Organic Acids in Aqueous Solution,” IUPAC Chemical Data Series No. 23, Pergamon Press, Oxford, 1979.

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