Formamide
Formamide (HCONH₂), the simplest monocarboxylic amide, is a colorless, viscous liquid with a faint ammoniacal odor, molecular weight of 45.04 g/mol, melting point of 2–3 °C, boiling point of 210 °C, and density of 1.134 g/mL at 25 °C.[1][2] It is fully miscible with water, ethanol, and acetone, making it a versatile polar solvent, though it decomposes slowly in moist air to formic acid and ammonia.[3][4] Industrially, formamide is primarily produced by the ammonolysis of methyl formate, though alternative methods include the carbonylation of ammonia with carbon monoxide under catalytic conditions.[4][5] It serves as a key chemical intermediate in the manufacture of pharmaceuticals, agrochemicals, dyes, and plastics, and is notably used in the large-scale production of hydrogen cyanide via dehydration.[1][3] Additionally, formamide functions as an effective solvent for processing polymers like polyacrylonitrile and as a denaturing agent in biochemical applications, such as stabilizing RNA during gel electrophoresis.[2]Properties
Physical properties
Formamide has the molecular formula HCONH₂ and a molecular weight of 45.04 g/mol.[1] It is a colorless, hygroscopic liquid with a faint ammonia-like odor.[1][6] Key physical constants of formamide are summarized in the following table:| Property | Value | Conditions |
|---|---|---|
| Melting point | 2.55 °C | - |
| Boiling point | 210 °C | 760 mmHg |
| Density | 1.134 g/cm³ | 20 °C |
| Viscosity | 3.76 mPa·s | 20 °C (dynamic) |