Dissociation Constants Of Organic Acids And Bases
This table lists the acid-base dissociation constants of over 600 organic compounds, including many amino acids.  All data apply to
dilute aqueous solutions and are presented in the form of pKa, which is the negative of the logarithm of the acid dissociation constant Ka.
Molecular
formula
Name Step TIC pKa
CH2O2 Formic acid 20 3.75
CH5N Methylamine 25 10.63
C2HCl3O2 Trichloroacetic acid 25 0.70
C2H2Cl2O2 Dichloroacetic acid 25 1.48
C2H2O3 Glyoxylic 25 3.18
C2H2O4 Oxalic acid 1 25 1.23
2 25 4.19
C2H3BrO2 Bromoacetic acid 25 2.69
C2H3ClO2 Chloroacetic acid 25 2.85
C2H3IO2 Iodoacetic acid 25 3.12
C2H4OS Thioacetic acid 25 3.33
C2H4O2 Acetic acid 25 4.76
C2H4O3 Glycolic acid 25 3.83
C2H5N Ethyleneimine 25 8.01
C2H5NO Acetamide 25 0.63
C2H5NO2 Glycine 1 25 2.35
2 25 9.78
C2H6O2 Ethylene glycol 25 14.22
C2H7AsO2 Cacodylic acid 1 25 1.57
2 25 6.27
C2H7N Dimethylamine 25 10.68
C2H7N Ethylamine 25 10.70
C2H7NO Ethanolamine 25 9.50
C2H7NO3S Taurine 1 25 1.5
2 25 9.061
C2H7NS Cysteamine 1 25 8.35
2 25 10.81
C2H8N2 1,2-Ethanediamine 1 0 10.712
2 0 7.564
C3H3NO2 Cyanoacetic acid 25 2.45
C3H3NS Thiazole 20 2.44
C3H4N2 1H-Imidazole 25 6.953
C3H4N2S 2-Thiazolamine 20 5.36
C3H4O2 Acrylic acid 25 4.25
C3H4O3 Pyruvic acid 25 2.39
C3H4O4 Malonic acid 1 25 2.83
2 25 5.69
C3H5ClO2 2-Chloropropanoic acid 25 2.83
C3H5ClO2 3-Chloropropanoic acid 25 3.98
C3H6N6 Melamine 25 5.00
C3H6O2 Propanoic acid 25 4.86
C3H6O3 3-Hydroxypropanoic acid 25 4.51
C3H6O3 Lactic acid 100 3.08
C3H6O4 Glyceric acid 25 3.52
C3H7N Azetidine 25 11.29
C3H7NO2 L-Alanine 1 25 2.34
2 25 9.87
C3H7NO2 b-Alanine 1 25 3.55
2 25 10.24
C3H7NO2 Methylglycine 1 25 2.21
2 25 10.12
C3H7NO2S Cysteine 1 25 1.92
2 25 8.37
3 25 10.70
C3H7NO3 Serine 1 25 2.19
2 25 9.21
C3H7NO5S l-Cysteic acid 1 25 1.3
2 25 1.9
3 25 8.70
C3H7N3O2 Glycocyamine 25 2.82
C3H8O3 Glycerol 25 14.15
C3H9N Propylamine 20 10.60
C3H9N Trimethylamine 25 9.80
C3H9NO 1-Amino-2-methoxyethane 10 9.89
C3H9NO Trimethylamine oxide 25 4.65
C3H10N2 1,2-Propanediamine 1 25 9.82
2 25 6.61
C3H10N2 1,3-Propanediamine 1 10 10.94
2 10 9.03
C3H11N3 1,2,3-Triaminopropane 1 20 9.59
2 20 7.95
C4H4N2 Pyrazine 27 0.65
C4H4N2 Pyridazine 20 2.24
C4H4N2O3 Barbituric acid 25 4.01
C4H4N2O5 Alloxanic acid 25 6.64
C4H4N4O2 5-Nitropyrimidinamine 20 0.35
C4H4O4 trans-Fumaric acid 1 18 3.03
2 18 4.44
C4H4O4 Maleic acid 1 25 1.83
2 25 6.07
C4H4O5 Oxaloacetic acid 1 25 2.22
2 25 3.89
3 25 13.03
C4H5N3 2-Pyrimidinamine 20 3.45
C4H6N2 1-Methylimidazol 25 6.95
C4H6N4O3 Allantoin 25 8.96
C4H6O2 3-Butenoic acid 25 4.34
C4H6O2 trans-Crotonic acid 25 4.69
C4H6O3 Acetoacetic acid 18 3.58
C4H6O3 2-Oxobutanoic acid 25 2.50
C4H6O4 Methymalonic acid 1 25 3.07
2 25 5.76
C4H6O4 Succinic acid 1 25 4.16
2 25 5.61
C4H6O5 Malic acid 1 25 3.40
2 25 5.11
C4H6O6 a-Tartaric acid 1 25 2.98
2 25 4.34
C4H6O6 meso-Tartaric acid 1 25 3.22
2 25 4.82
C4H6O8 Dihydroxytartaric acid 25 1.92
C4H7CIO2 2-Chlorobutanoic acid RT 2.86
C4H7CIO2 3-Chlorobutanoic acid RT 4.05
C4H7CIO2 4-Chlorobutanoic acid RT 4.52
C4H7NO2 4-Cyanobutanoic acid 25 2.42
C4H7NO3 N-Acetylglycine 25 3.669
C4H7NO4 Aspartic acid 1 25 1.99
2 25 3.90
3 25 9.90
C4H7N3O Creatinine 1 25 4.83
2 9.2
C4H8N2O3 Asparagine 1 20 2.17
2 20 8.80
C4H8N2O3 N-Glycylglycine 25 3.139
C4H8O2 Butanoic acid 25 4.83
C4H8O2 2-Methylpropanoic acid 25 4.88
C4H8O3 3-Hydroxybutanoic acid 25 4.70
C4H8O3 4-Hydroxybutanoic acid 25 4.72
C4H9N Pyrrolidine 25 11.27
C4H9NO Morpholine 25 8.33
C4H9NO2 2-Aminobutanoic acid 1 25 2.29
2 25 9.83
C4H9NO2 4-Aminobutanoic acid 1 25 4.031
2 25 10.556
C4H9NO2 N,N-Dimethylglycine 25 9.89
C4H9NO2 2-Methylalanine 1 25 2.36
2 25 10.21
C4H9NO2S Homocysteine 1 25 2.22
2 25 8.87
3 25 10.86
C4H9NO3 Homoserine 1 25 2.71
2 25 9.62
C4H9NO3 DL-Methoxyalanine 25 2.037
C4H9NO3 Threonine 1 25 2.09
2 25 9.10
C4H9N3O2 Creatine 1 25 2.63
2 25 14.3
C4H10N2 Piperazine 1 23 9.83
2 23 5.56
C4H10N2O2 2,4-Diaminobutanoic acid 1 25 1.85
2 25 8.24
3 25 10.44
C4H11N Butylamine 20 10.77
C4H11N sec-Butylamine 25 10.56
C4H11N tert-Butylamine 25 10.68
C4H11N Diethylamine 40 11.02
C4H12N2 1,4-Butanediamine 1 20 10.80
2 20 9.35
C4H12O2 1,2-Dimethylaminoethane 1 25 10.40
2 25 8.26
C5H4BrN 3-Bromopyridine 25 2.84
C5H4CIN 3-Chloropyridine 25 2.84
C5H4N4 Purine 1 20 2.30
2 20 8.96
C5H4N4O3 Uric acid 12 3.89
C5H5N Pyridine 25 5.25
C5H5NO 4-Pyridinol 1 20 3.20
2 20 11.12
C5H5NO 2(1H)-Pyridinone 1 20 0.75
2 20 11.65
C5H5N5 1H-Purin-6-amine 1 25 4.12
2 25 9.83
C5H6N2 2-Methylpyrazine 27 1.45
C5H6N2 2-Pyridinamine 20 6.82
C5H6N2 4-Pyridinamine 25 9.114
C5H6O4 1,1-Cyclopropanedicarboxylic acid 1 25 1.82
2 25 7.43
C5H6O4 Itaconic acid 1 25 3.85
2 25 5.45
C5H6O4 Mesaconic acid 1 25 3.09
2 25 4.75
C5H6O5 2-Oxoglutaric acid 1 25 2.47
2 25 4.68
C5H7NO3 L-2-Pyrrolidone-5-carboxylic acid 25 3.32
C5H7N3 Methylaminopyrazine 25 3.39
C5H7N3 2,5-Pyridinediamine 20 6.48
C5H8N2 2,4-Dimethylimidazzol 25 8.36
C5H8O4 Dimethylmalonic acid 25 3.15
C5H8O4 Glutaric acid 1 25 4.31
2 25 5.41
C5H8O4 Methylsuccinic acid 1 25 4.13
2 25 5.64
C5H9NO2 Proline 1 25 1.952
2 25 10.64
C5H9NO3 5-Aminolevulinic acid 1 25 4.05
2 25 8.90
C5H9NO3 trans-4-Hydroxyroline 1 25 1.818
2 25 9.662
C5H9NO3 8-Hydroxypurine 1 20 2.56
2 20 8.26
C5H9NO4 L-Glutamic acid 1 25 2.13
2 25 4.31
C5H9N3 Histamine 1 25 6.04
2 25 9.75
C5H10N2O3 L-Glutamine 1 25 2.17
2 25 9.13
C5H10N2O3 Glycylalanine 25 3.15
C5H10N2O4 Glycylserine 1 25 2.98
2 25 8.38
C5H10O2 2-Methylbutanoic acid 25 4.80
C5H10O2 3-Methylbutanoic acid 25 4.77
C5H10O2 Pentanoic acid 25 4.84
C5H10O2 Trimethylacetic acid   25 5.03
C5H11N N-Methylpyrrolidine 25 10.32
C5H11N Piperidine 25 11.123
C5H11NO2 5-Aminopentanoic acid 1 25 4.27
2 25 10.766
C5H11NO2 Betaine 0 1.83
C5H11NO2 Norvaline 1 25 2.32
2 25 9.81
C5H11NO2 N-Propylglycine 1 25 2.35
2 25 10.19
C5H11NO2 Valine 1 25 2.29
2 25 9.74
C5H11NO2S Methionine 1 25 2.13
2 25 9.27
C5H12N2O2 Ornithine 1 25 1.705
2 25 8.69
3 25 10.76
C5H13N 1-Aminno-2,2-dimethylpropane 25 10.15
C5H13N Diethylmethylamine 25 10.35
C5H13N 3-Methyl-1-butanamine 25 10.60
C5H13N 2-Methyl 2-butanamine 19 10.85
C5H13N 3-Pentanamine 17 10.59
C5H13N Pentylamine 25 10.63
C5H14NO Choline 25 13.9
C5H14N2 Cadaverine 1 25 10.05
2 25 10.93
C6H3CIN4 6-Cbloropteridine 20 3.68
C6H3N3O7 Picric acid 25 0.38
C6H4Cl2O 2,3-Dichlorophenol 25 7.44
C6H4N2O3 5-Hydroxylysine 25 2.13
C6H4N2O5 2,4-Dinitrophenol 15 3.96
C6H4N2O5 3,6-Dinitrophenol 15 5.15
C6H4N4 Pteridine 20 4.05
C6H5Br2N 3,5-Dibromoaniline 25 2.34
C6H5CIO 2-Chlorophenol 25 8.49
C6H5CIO 3-Chlorophenol 25 8.85
C6H5CIO 4-Chlorophenol 25 9.18
C6H5CI2N 2,4-Dichloroaniline 22 2.05
C6H5NO 2-Pyridinecarboxaldehyde 20 3.80
C6H5NO2 Nitrobenzene 0 3.98
C6H5NO2 Picolinic acid 1 25 1.07
2 25 5.25
C6H5NO2 3-Pyridinecarboxylic acid 25 4.85
C6H5NO2 4-Pyridinecarboxylic acid 25 4.96
C6H5NO3 2-Nitrophenol 25 7.17
C6H5NO3 3-Nitrophenol 25 8.28
C6H5NO3 4-Nitrophenol 25 7.15
C6H5N5O 2-Amino-4-hydroxypteridine 1 20 2.27
2 20 7.96
C6H5N5O2 Xanthopterin 2 20 6.59
3 20 9.31
C6H6BrN 2-Bromoaniline 25 2.53
C6H6BrN 3-Bromoaniline 25 3.58
C6H6BrN 4-Bromoaniline 25 3.86
C6H6CIN 2-Chloroaniline 25 2.65
C6H6CIN 3-Chloroaniline 25 3.46
C6H6CIN 4-Chloroaniline 25 4.15
C6H6FN 2-Fluoroaniline 25 3.20
C6H6FN 3-Fluoroaniline 25 3.50
C6H6FN 4-Fluoroaniline 25 4.65
C6H6IN 2-Iodoaniline 25 2.60
C6H6N2O 2-Pyridinecarboxaldehyde,oxime 1 20 3.59
2 20 10.18
C6H6N2O2 2-Nitroaniline 25 -0.26
C6H6N2O2 3-Nitroaniline 25 2.466
C6H6N2O2 4-Nitroaniline 25 1.0
C6H6O Phenol 20 9.89
C6H6O2 Hydroquinone 20 10.35
C6H6O2 Pyrocatechol 20 9.85
C6H6O2 Resorcinol 25 9.81
C6H6O3S Benzenesulfonic acid 25 0.70
C6H6O6 cis-Aconitic acid 25 1.95
C6H6O6 trans-Aconitic acid 1 25 2.80
2 25 4.46
C6H7N Aniline 25 4.63
C6H7N 2-Methylpyridine 20 5.97
C6H7N 3-Methylpyridine 20 5.68
C6H7N 4-Methylpyridine 20 6.02
C6H7NO Methoxypyridine 25 6.47
C6H7NO3S o-Aminobenzenesulfonic acid 25 2.48
C6H7NO3S m-Aminobenzenesulfonic acid 25 3.73
C6H7NO3S p-Aminobenzenesulfonic acid 25 3.24
C6H8N2 N-Methylpyridinamine 20 9.65
C6H8O6 Ascorbic acid 1 24 4.10
2 16 11.79
C6H8O7 Citric acid 1 20 3.14
2 20 4.77
3 20 6.39
C6H8O7 Isocitric acid 1 25 3.29
2 25 4.71
3 25 6.40
C6H9NO6 g-Carboxyglutamic acid 1 25 1.7
2 25 3.2
3 25 4.75
4 25 9.9
C6H9N3 4,6-Dimethylpyrimidinamine 20 4.82
C6H9N3O2 Histidine 1 25 1.80
2 25 6.04
3 25 9.33
C6H10O3 2-Oxo-3-methylpentanoic acid 25 2.3
C6H10O4 Adipic acid 1 25 4.43
2 25 5.41
C6H10O4 3-Methylglutaric acid 25 4.24
C6H11NO2 l-Pipecolic acid 1 25 2.28
2 25 10.72
C6H11NO3 Adiparnic acid 25 4.63
C6H11NO4 2-Aminoadipic macid 1 25 2.14
2 25 4.21
3 25 9.77
C6H11N3O4 Glycylasparagine 1 25 2.942
2 18 8.44
C6H11N3O4 N-(N-Glycylglycyl)glycine 1 25 3.225
2 25 8.09
C6H12N2O4S2 Cystine 1 35 2.1
2 35 8.0
C6H12O2 Hexanoic acid 25 4.85
C6H12O2 4-Methylpentanoic acid 18 4.84
C6H13N Cyclohexylamine 24 10.66
C6H13N 1,2-Dimethylpyrrolidine 26 10.20
C6H13N 1-Methylpiperidine 25 10.08
C6H13NO2 6-Aminohexanoic acid 1 25 4.373
2 25 10.804
C6H13NO2 Isoleucine 1 25 2.32
2 25 9.76
C6H13NO2 L-Leucine 1 25 2.328
2 25 9.744
C6H13NO2 Norleucine 1 25 2.335
2 25 9.83
C6H13N3O3 Citrulline 1 25 2.43
2 25 9.69
C6H14N2 cis-1,2-Cyclohexanediamine 1 20 9.93
2 20 6.13
C6H14N2 trans-1,2-Cyclohexanediamine 1 20 9.94
2 20 6.47
C6H14N2 2,5-Dimethylpiperazine 1 25 9.66
2 25 5.20
C6H14N2O2 Lysine 1 25 2.16
2 25 9.06
3 25 10.54
C6H14N4O2 Arginine 1 25 1.82
2 25 8.99
3 25 12.48
C6H15N 3-Amino-3-methylpentane 16 11.01
C6H15N Diisopropylamine 25 11.05
C6H15N Hexylamine 25 10.56
C6H15N Triethylamine 25 10.75
C6H16N2 Hexamethylenediamine 1 0 11.857
2 0 10.762
C7H5BrO2 2-Bromobenzoic acid 25 2.84
C7H5BrO2 3-Bromobenzoic acid 25 3.86
C7H5CIO2 2-Chlorobenzoic acid 25 2.92
C7H5CIO2 3-Chlorobenzoic acid 25 3.82
C7H5CIO2 4-Chlorobenzoic acid 25 3.98
C7H5IO2 2-Iodobenzoic acid 25 2.85
C7H5IO2 3-Iodobenzoic acid 25 3.80
C7H5NO3S Saccharin 18 11.68
C7H5NO4 Dinicotinic acid 25 2.80
C7H5NO4 Dipicolinic acid 1 25 2.16
2 25 4.76
C7H5NO4 Lutidinic acid 25 2.15
C7H5NO4 2-Nitrobenzoic acid 18 2.16
C7H5NO4 3-Nitrobenzoic acid 25 3.47
C7H5NO4 4-Nitrobenzoic acid 25 3.41
C7H5NO4 Quinolinic acid 1 25 2.43
2 25 4.78
C7H6N2 Benzimidazole 25 5.532
C7H6N4O 6-Hydroxy-4-methylpteridine 1 20 4.08
2 20 6.41
C7H6O2 Benzoic acid 25 4.19
C7H6O3 o-Hydroxy-4-methylpteridine 1 19 2.97
2 18 13.40
C7H6O3 m-Hydroxybenzoic acid 1 19 4.06
2 19 9.92
C7H6O3 p-Hydroxybenzoic acid 1 19 4.48
2 19 9.32
C7H6O4 2,5-Dihydroxybenzoic acid 1 25 2.97
C7H6O4 3,4-Dihydroxybenzoic acid 1 25 4.48
2 25 8.83
3 25 12.6
C7H6O4 3,5-Dihydroxybenzoic acid 1 25 4.04
C7H6O4 Dihydroxymalic acid 25 1.92
C7H6O5 Gallic acid 25 4.41
C7H6O5 2,4,6-Trihydroxybenzoic acid 25 1.68
C7H7NO2 2-Aminobenzoic acid 1 25 2.108
2 25 4.946
C7H7NO2 3-Aminobenzoic acid 2 25 4.78
C7H7NO2 4-Animobenzoic acid 1 25 2.501
2 25 4.874
C7H8N4O2 Theobromine 18 7.89
C7H8O o-Cresol 25 10.20
C7H8O m-Cresol 25 10.01
C7H8O p-Cresol 25 10.17
C7H9N Benzylamine 25 9.33
C7H9N 2,3-Dimethylpyridine 25 6.57
C7H9N 2,4-Dimethylpyridine 25 6.99
C7H9N 2,5-Dimethylpyridine 25 6.40
C7H9N 2,6-Dimethylpyridine 25 6.65
C7H9N 3,4-Dimethylpyridine 25 6.46
C7H9N 3,5-Dimethylpyridine 25 6.15
C7H9N 2-Ethylpyridine 25 5.89
C7H9N N-Methylaniline 25 4.84
C7H9N o-Methylaniline 25 4.44
C7H9N m-Methylaniline 25 4.73
C7H9N p-Methylaniline 25 5.08
C7H9NO o-Anisidine 25 4.52
C7H9NO m-Anisidine 25 4.23
C7H9NO p-Anisidine 25 5.34
C7H9NS 4-Methylthioaniline 25 4.35
C7H9N5 2-Dimethylaminopurine 1 20 4.00
2 20 10.24
C7H11N3O2 l-1-Methylhistidine 1 25 1.69
2 25 6.48
3 25 8.85
C7H11N3O2 l-3-Methylhistidine 1 25 1.92
2 25 6.56
3 25 8.73
C7H12O2 Cyclohexanecarboxylic acid 25 4.90
C7H12O4 Heptanedioic acid 1 25 4.71
2 25 5.58
C7H13NO 3-Acetylpiperidine 25 3.18
C7H13NO4 a-Ethylglutamic acid 1 25 3.846
2 25 7.838
C7H14O2 Heptanoic acid 25 4.89
C7H15N 1,2-Dimethylpiperidine 25 10.22
C7H15N 1-Ethylpiperidine 23 10.45
C7H15NO3 Carnitine 25 3.80
C7H17N 2-Heptanamine 19 10.7
C7H17N Heptylamine 25 10.67
C8H6N2 Cinnoline 20 2.37
C8H6N2 Quinazoline 20 3.43
C8H6N2 Quinoxaline 20 0.56
C8H6N2O 5-Hydoxxyquinazoline 1 20 3.62
2 20 7.41
C8H6O4 o-Phthalic acid 1 25 2.89
2 25 5.51
C8H6O4 m-Phthalic acid 1 25 3.54
2 18 4.60
C8H6O4 p-Phthalic acid 1 25 3.51
2 16 4.82
C8H6O4 Terephthalic acid 25 3.51
C8H7CIO2 2-Chlorophenylacetic acid 25 4.07
C8H7CIO2 3-Chlorophenylacetic acid 25 4.14
C8H7CIO2 4-Chlorophenylacetic acid 25 4.19
C8H7CIO3 2-Chlorophenoxyacetic acid 25 3.05
C8H7CIO3 3-Chlorophenoxyacetic acid 25 3.10
C8H7NO4 2-Nitrophenylacetic acid 25 4.00
C8H7NO4 3-Nitrophenylacetic acid 25 3.97
C8H7NO4 4-Nitrophenylacetic acid 25 3.85
C8H8N2 2-Methylbenzimidazole 25 6.19
C8H8O2 Phenylacetic acid 18 4.28
C8H8O2 o-Toluic acid 25 3.91
C8H8O2 m-Toluic acid 25 4.27
C8H8O2 p-Toluic acid 25 4.36
C8H8O3 DL-Mandelic acid 25 3.85
C8H8O4 Homogentisic acid 25 4.40
C8H9NO2 2-(Methylamino)benzoic acid 25 5.34
C8H9NO2 3-(Methylamino)benzoic acid 25 5.10
C8H9NO2 4-(Methylamino)benzoic acid 25 5.04
C8H9NO2 Phenylglycine 1 25 1.83
2 25 4.39
C8H10BrN 4-Bromo-N,N-dimethylaniline 25 4.23
C8H10CIN 3-Chloro-N,N-dimethylaniline 20 3.83
C8H10CIN 4-Chloro-N,N-dimethylaniline 20 4.39
C8H10N2O2 N,N-Dimethyl-3-nitroaniline 25 2.62
C8H11N N,N-Dimethylaniline 25 5.15
C8H11N N-Ethylaniline 24 5.12
C8H11N Phenylethylamine 25 9.84
C8H11N 2,4,6-Trimethylpyridine 25 7.43
C8H11NO o-Phenetidine 28 4.43
C8H11NO m-Phenetidine 25 4.18
C8H11NO p-Phenetidine 28 5.20
C8H11NO Tyramine 1 25 9.74
2 25 10.52
C8H11NO2 Dopamine 1 25 8.9
2 25 10.6
C8H11NO3 Noradrenaline 1 25 8.64
2 25 9.70
C8H12N2O3 Veronal 25 7.43
C8H14O4 Octanedioic acid 25 4.52
C8H16N2O3 N-Glycylleucine 25 3.18
C8H16N2O3 N-Leucylglycine 1 25 3.25
2 25 8.2
C8H16N2O4S2 Homocystine 1 25 1.59
2 25 2.54
3 25 8.52
4 25 9.44
C8H16O2 Octanoic acid 25 4.89
C8H17N 2,2,4-Trimethylpiperidine 30 11.04
C8H19N Dibutylamine 21 11.25
C8H19N N-Methyl-2-heptanamine 17 10.99
C8H19N Octylamine 25 10.65
C9H6BrN 3-Bromoquinoline 25 2.69
C9H7CIO2 o-Chlorocinnamic acid 25 4.23
C9H7CIO2 m-Chlorocinnamic acid 25 4.29
C9H7CIO2 p-Chlorocinnamic acid 25 4.41
C9H7N Isoquinoline 20 5.42
C9H7N Quinoline 20 4.90
C9H7NO 7-Isoquinolinol 1 20 5.68
2 20 8.90
C9H7NO 3-Quinolinol 1 20 4.28
2 20 8.08
C9H7NO 8-Quinolinol 1 20 5.017
2 25 9.812
C9H7NO3 o-Cyanophenoxyacetic acid 25 2.98
C9H7NO3 m-Cyanophenoxyacetic acid 25 3.03
C9H7NO3 p-Cyanophenoxyacetic acid 25 2.93
C9H8N2 1-Isoquinolinamine 20 7.59
C9H8N2 3-Quinolinamine 20 4.91
C9H8O2 cis-Cinnamic acid 25 3.89
C9H8O2 trans-Cinnamic acid 25 4.44
C9H9CIO2 3-(2-Chlorophenyl)propanoic acid 25 4.58
C9H9CIO2 3-(3-Chlorophenyl)propanoic acid 25 4.59
C9H9CIO2 3-(4-Chlorophenyl)propanoic acid 25 4.61
C9H9I2NO3 3,5-Diiodityrosine 1 25 2.12
2 25 5.32
3 25 9.48
C9H9NO3 Hippuric acid 25 3.62
C9H9NO4 3-(2-Nitrophenyl)propanoic acid 25 4.50
C9H9NO4 3-(4-Nitrophenyl)propanoic acid 25 4.47
C9H10INO3 3-Iodotyrosine 1 25 2.2
2 25 8.7
3 25 9.1
C9H10N2 2-Ethylbenzimidazole 25 6.18
C9H10O2 Mesitylenic acid 25 4.32
C9H10O2 a-Phenylpropanoic acid 25 4.64
C9H10O2 b-Phenylpropanoic acid 25 4.37
C9H11N N-Allylaniline 25 4.17
C9H11N 1-Aminoindane 22 9.21
C9H11NO2 Phenylalanine 1 25 2.20
2 25 9.31
C9H11NO3 Tyrosine 1 25 2.20
2 25 9.21
3 25 10.46
C9H11NO4 L-3,4-Dihydroxyphenylalanine 1 25 2.32
2 25 8.72
3 25 9.96
4 25 11.79
C9H12N2O2 Tyrosineamide 25 7.33
C9H13NO3 D-Adrenaline 1 25 8.66
2 25 9.95
C9H14N4O3 N-b-Alanylhistidine 1 20 2.73
2 20 6.87
3 20 9.73
C9H14N4O3 L-Carnosine 1 25 2.62
2 25 6.66
3 25 9.24
C9H18O2 Nonanic acid 25 4.96
C9H19N 1-Butylpiperidine 23 10.47
C9H19N 2,2,6,6-Tetramethylpiperidine 25 11.07
C9H21N Nonylamine 25 10.64
C10H7NO2 8-Quinolinecarboxylic acid 25 1.82
C10H8O 1-Naphthol 25 9.34
C10H8O 2-Naphthol 25 9.51
C10H9N 2-Methylquinoline 20 5.83
C10H9N 4-Methylquinoline 20 5.67
C10H9N 5-Methylquinoline 20 5.20
C10H9N a-Naphthylamine 25 3.92
C10H9N b-Naphthylamine 25 4.16
C10H9NO 1-Amino-6-hydroxynaphthalene 25 3.97
C10H9NO 6-Methoxyquinoline 20 5.03
C10H10O2 o-Methylcinnamic acid 25 4.50
C10H10O2 m-Methylcinnamic acid 25 4.44
C10H10O2 p-Methylcinnamic acid 25 4.56
C10H12N2 Tryptamine 25 10.2
C10H12N2O 5-Hydroxytryptamine 1 25 9.8
2 25 11.1
C10H12O2 4-Phenylbutanoic acid 25 4.76
C10H12O3 2-(m-Anisyl)propanoic acid 25 4.65
C10H12O3 2-(p-Anisyl)propanoic acid 25 4.69
C10H12O3 2-(o-Anisyl)propanoic acid 25 4.80
C10H14N2 Nicotine 1 25 8.02
2 25 3.12
C10H15N N,N-Diethylaniline 22 6.61
C10H15NO d-Ephedrine 10 10.139
C10H15NO l-Ephedrine 10 9.958
C10H17N3O6S l-Glutathione 1 25 2.12
2 25 3.59
3 25 8.75
4 25 9.65
C10H17N5O6 Tetraglycylglycine 1 20 3.10
2 20 8.02
C10H18N4O5 L-Argininosuccinic acid 1 25 1.62
2 25 2.70
3 25 4.26
4 25 9.58
C10H19N Bornylamine 25 10.17
C10H19N Neobornylamine 25 10.01
C10H21N Butylcyclohexylamine 25 11.23
C10H23N Decylamine 25 10.64
C11H8N2 Perimidine 20 6.35
C11H8O2 1-Naphthoic acid 25 3.70
C11H8O2 2-Naphthoic acid 25 4.17
C11H11N Methyl-1-naphthylamine 27 3.67
C11H12N2O2 Tryptophan 1 25 2.46
2 25 9.41
C11H16N2O2 Pilocarpine 30 6.87
C11H25N Undecylamine 25 10.63
C12H8N2 1,10-Phenanthroline 25 4.84
C12H11N 2-Aminobiphenyl 22 3.82
C12H11N 2-Benzylpyridine 25 5.13
C12H11N Diphenylamine 25 0.79
C12H11N3 4-Aminoazobenzene 25 2.82
C12H12N2 p-Benzidine 1 30 4.66
2 30 3.57
C12H13N N,N-Dimethyl-1-naphthylamine 25 4.83
C12H13N N,N-Dimethyl-2-naphthylamine 25 4.566
C12H27N Dodecylamine 25 10.63
C13H9N Acridine 20 5.58
C13H9N Phenanthridine 20 5.58
C13H10N2 2-Phenylbenzimidazole 1 25 5.23
2 25 11.91
C13H10O2 2-Phenylbenzoic acid 25 3.46
C13H12N2O 4-(p-Aminobenzoyl)aniline 1 25 2.93
C13H13N 4-Benzylaniline 25 2.17
C13H29N Tridecylamine 25 10.63
C14H12O2 Diphenylacetic acid 25 3.94
C14H15N3 4-Dimethylaminoazobenzene 25 3.226
C14H31N Tetradecylamine 25 10.62
C15H11I4NO4 L-Thyroxine 1 25 2.2
2 25 6.45
3 25 10.1
C15H33N Pentadecylamine 25 10.61
C16H35N Hexadecylamine 25 10.63
C17H19NO3 Morphine 25 8.21
C18H21NO3 Codeine 25 8.21
C18H39N Octadecylamine 25 10.60
C20H21NO4 Papaverine 25 6.40
C20H24N2O2 Quinine 1 25 8.52
2 25 4.13
C21H22N2O2 Strychnine 25 8.26
C23H26N2O4 Brucine 1 25 8.28
References
1. Perrin, D. D., Dissociation Constants of Organic Bases in Aqueous Solution, Butterworths, London, 1965; Supplement, 1972.
2. Serjeant, E. P., and Dempsey, B., Ionization Constants of Organic Acids in Aqueous Solution, Pergamon, Oxford, 1979.
3. Albert, A., "Ionization Constants of Heterocyclic Substances", in Physical Methods in Heterocyclic Chemistry, Katritzky, A. R., Ed.,
    Academic Press, New York, 1963.
4. Sober, H. A., Ed., CRC Handbook of Biochemistry, CRC Press, Cleveland, Ohio, 1968.
5. Perrin, D. D., Dempsey, B., and Serjeant, E. P., pKa Prediction for Organic Acids and Bases, Chapman & Hall, London, 1981.
6. Dawson, R. M. C., Elliot, D. C., Elliot, W. H., and Jones, K. M., Data for Biochemical Research, Oxford Science Publications,
    Oxford, 1986.