Substance profile
Acetaldehyde
Acetaldehyde is a volatile liquid or gas with a pungent, fruity odor.
01 · Identification
What Acetaldehyde is
Acetaldehyde is a volatile liquid or gas with a pungent, fruity odor. Its molecular formula is C2H4O and its molecular weight is 44.05 g/mol. It boils at 20.8 °C, melts at -123 °C, is miscible with water.
Under the GHS it carries the signal word Danger. It is classed as hazardous Air Pollutants (HAPs).
Other names for Acetaldehyde
- ethanal
02 · GHS classification
Hazards and label elements
Harmonised classification under CLP Annex VI. This is the legally binding classification in the EU; other jurisdictions may differ.
| Code | Hazard statement |
|---|---|
| H224 | Extremely flammable liquid and vapour. |
| H350 | May cause cancer <state route of exposure if it is conclusively proven that no other routes of exposure cause the hazard>. |
| H341 | Suspected of causing genetic defects <state route of exposure if it is conclusively proven that no other routes of exposure cause the hazard>. |
| H335 | May cause respiratory irritation. |
| H319 | Causes serious eye irritation. |
Precautionary statements: P201, P210, P233, P241, P242, P264, P280, P305, P308, P313, P337, P338, P403
03 · Physical and chemical properties
Acetaldehyde properties
Every value is shown with the conditions it was measured under and the source it came from. Where sources disagree, all values are listed rather than one being picked — the difference is usually a different form of the substance, not an error.
| Property | Value | Conditions | Source |
|---|---|---|---|
| Boiling point | 20.8 °C (69.4 °F) | HSDB | |
| 20.56 °C (69 °F) | NIOSH | ||
| 21.11 °C (70 °F) | at 760 mmHg | CAMEO | |
| Melting point | -123.4 °C (-190.1 °F) | HSDB | |
| -123.33 °C (-190 °F) | NIOSH | ||
| -123.5 °C (-190.3 °F) | CAMEO | ||
| Density | 0.79 g/cm³ | NIOSH | |
| 0.78 g/cm³ | at 20 °C | CAMEO | |
| 0.7834 g/cm³ | at 18 °C | HSDB | |
| Solubility | Miscible with ethanol, ether, benzene; slightly soluble in chloroform | HSDB | |
| Miscible with water /1X10+6 mg/L at 25 °C/ | at 25 °C | HSDB | |
| Vapor pressure | 740 mmHg | NIOSH | |
| 757.562 mmHg | at 20 °C | ICSC | |
| 902 mmHg | at 25 °C | HSDB | |
| Flash point | -40 °C (-40 °F) | HSDB | |
| -38.89 °C (-38 °F) | Closed cup | HSDB | |
| -37.78 °C (-36 °F) | NIOSH | ||
| Autoignition temperature | 175 °C (347 °F) | HSDB | |
| 185 °C (365 °F) | CAMEO | ||
| Lower explosive limit (LEL) | 4 % by volume | HSDB | |
| Upper explosive limit (UEL) | 60 % by volume | HSDB | |
| 60 % by volume | From table | HSDB | |
| Vapor density | 1.52 (air = 1) | HSDB | |
| 1.5 (air = 1) | ICSC | ||
| Odor threshold | Recognition in air= 2.1x10-1 ppm (chemically pure) | HSDB | |
| Odor low: 0.0002 mg/cu m; Odor high: 4.14 mg/cu m | HSDB | ||
| Odor Threshold Low: 0.0028 [ppm] | Haz-Map | ||
| Critical temperature and pressure | 181.5 °C (358.7 °F) | HSDB |
Values compiled from PubChem Laboratory Chemical Safety Summary. Temperatures converted to Fahrenheit for reference.
04 · Source notes
Further notes on Acetaldehyde
These are descriptions rather than measured values, so they are kept out of the table above and quoted here with the source that reported them.
Solubility
Acetaldehyde is miscible in all proportions with water and most common organic solvents, eg, acetone, benzene, ethyl alcohol, ethyl ether, gasoline, paraldehyde, toluene, xylenes, turpentine, and acetic acid.
Source: HSDB
05 · Handling and storage
Storing and handling Acetaldehyde
Storage conditions
Conditions for safe storage, including any incompatibilities: Keep container tightly closed in a dry and well-ventilated place. Containers which are opened must be carefully resealed and kept upright to prevent leakage. Recommended storage temperature: 2 - 8 °C.
Source: Hazardous Substances Data Bank (HSDB)
Incompatible materials
Incompatible materials: Oxidizing agents, reducing agents, acids, nitric acid, peroxides, bases, sodium hydroxide, amines, ammonia, oxygen. Warning: Acetaldehyde is oxidized rapidly and exothermically by air, to acetic acid, acid anhydrides, alcohols, halogens, ketones, phenol, hydrogen sulfide gas, hydrogen peroxide.
Source: Hazardous Substances Data Bank (HSDB)
Planning storage for a mix of chemicals? Check Acetaldehyde in the storage compatibility matrix →