Dissociation Constants Of Organic Acids And Bases

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 pK_a, which is the negative of the logarithm of the acid dissociation constant K_a.


Molecular formula	Name	Step	T_I°C	pK_a
CH2O2	Formic acid		20	3.75
CH4N2O	Urea		21	0.10
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
C5H10N2O2	Diaminopimelic acid	1	25	1.8
		2	25	2.2
		3	25	8.8
		4	25	9.9
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., pK_a 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.