Table 1 Relative reactivity of isocyanates with nucleophiles (Herrington & Hock 1998)
Nucleophile with active hydrogen | Structure | Relative reaction rate (uncatalysed, 25 °C) |
|---|---|---|
Primary aliphatic amine | R-NH2 | 100,000 |
Secondary aliphatic amine | R-NH-R’ | 20,000–50,000 |
Primary aromatic amine | Ar-NH2 | 200–300 |
Primary hydroxyl | R-CH2-OH | 100 |
Water | H2O | 100 |
Carboxylic acid | R-COOH | 40 |
Secondary hydroxyl | R-CH(OH)-R’ | 30 |
Di-urea | R-NH-CO-NH-R’ | 15 |
Tertiary hydroxyl | (R)3-C-OH | 0.5 |
Urethane | R-NH-COOR | 0.3 |
Amide | R-CONH2 | 0.1 |