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Appendix B - Acidity Constants for Some Organic Compounds

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    Table B1: 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
    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  4.2; 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═C(CH3)CO2H

    		  4.7
    CH3CO2H  4.8
    CH3CH2CO2H  4.8
    (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
    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
    (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.