Table 4. Physico-Chemical Parameters of Aliphatic Carboxylic Acids and Ratio of Peak Intensities (Decomposition of Adsorpted Complex to Destruction of Hydrogen-bonded Complex).
| acid | chemical formula | Tb, °C | pKa59 | lgKow | Ich. ad/IH-bond |
|---|---|---|---|---|---|
| methanoic | HCOOH | 100.7 | 3.75 | –0.54 | - |
| ethanoic | CH3COOH | 117.72 | 4.756 | –0.31 | 0.55 I(m/z 42)/I(m/z 60) |
| propanoic | CH3CH2COOH | 140.8 | 4.87 | 0.33; 0.25 | 0.83 I(m/z 56)/I(m/z 74) |
| butanoic | CH3(CH2)2COOH | 163.25 | 4.83 | 0.79 | 1.18 I(m/z 55)/I(m/z 60) |
| 2-methylpropanoic | (CH3)2CHCOOH | 4.84 | 0.87 calculated according to additive method60 | 1.03 I(m/z 55)/I(m/z 60) | |
| pentanoic | CH3(CH2)3COOH | 186.35 | 4.83 | 1.30 (Et2O) | 1.47 I(m/z 55)/I(m/z 60) |
| hexanoic | CH3(CH2)4COOH | 205.35 | 4.85 | 1.92 | 1.97 I(m/z 55)/I(m/z 60) |
| 2.2-dimethylpropanoic | (CH3)3CCOOH | 5.03 | 1.31 calculated according to additive method60 | ∞ | |
| octadecanoic acid(stearic) | C17H35COOH | 376.1 | 4.561 | 8.23 (estimated)61 | ∞ |