TABLE 4.
Acid Dissociation Constants in Different Solvents
| pKaa |
||||
|---|---|---|---|---|
| ion | neutral | CH3OH | CH3CN | DMSO |
| NO2− | nitrous acid | 7.5 | ||
| NO3− | nitric acid | 8.9136 | ||
| CH3CO2− | acetic acid | 9.5,140 9.6,135 9.6,148 9.6,156 9.7,154 9.8139 | 22.3,147 22.3,151 22.3153 | 12.3 |
| CH3CH2CO2− | propionic acid | 9.7,140 9.7156 | ||
| NCCH2CO2− | cyanoacetic acid | 18.0152 | ||
| CF3CO2− | trifluoroacetic acid | 12.7153 | ||
| C6H5CO2− | benzoic acid | 9.3,140 9.3,156 9.4,134 9.4,137 9.4,149 9.5139 | 20.7,142 20.7141 | 11.0 |
| p−FC6H4CO2− | 4-fluorobenzoic acid | 9.2156 | ||
| C6H5O− | phenol | 14.3,156 14.4,142 14.5148 | 26.7,138 27.2143 | 18.0 |
| p-NO2C6H4O− | 4-nitrophenol | 11.1,140 11.3,156 11.5148 | ||
| CH3O− | methanol | 29.0 | ||
| C2H5O− | ethanol | 29.8 | ||
| NH4+ | ammonia | 10.8156 | 16.5138 | 10.5 |
| CH3NH3+ | methylamine | 11.0156 | 18.4138 | 11.0 |
| (CH3)3NH+ | trimethylamine | 9.8156 | ||
| C5H10NH2+ | piperidine | 11.1156 | ||
| pyridineH+ | pyridine | 5.4,142 5.4156 | 12.3,138 12.3146 | 3.5 |
| C6H5NH3+ | aniline | 6.1156 | 10.6,138 10.7,144 10.7146 | 3.6 |
a
For anions, pKa of the neutral species. For cations, pKa of the ionic species. For methanol and acetonitril the literature reference for each experimental value is listed to the right of the value in superscript. For DMSO, a experimental values were taken from reference 155.