Substance profile
1,4-dihydroxybenzene
1,4-dihydroxybenzene is white crystals and is odorless.
01 · Identification
What 1,4-dihydroxybenzene is
1,4-dihydroxybenzene is white crystals and is odorless. Its molecular formula is C6H6O2 and its molecular weight is 110.11 g/mol. It boils at 285 °C, melts at 173 °C.
Under the GHS it carries the signal word Danger. It is classed as hazardous Air Pollutants (HAPs).
Other names for 1,4-dihydroxybenzene
- hydroquinone
- quinol
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 |
|---|---|
| H351 | Suspected of causing 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>. |
| H302 | Harmful if swallowed. |
| H318 | Causes serious eye damage. |
| H317 | May cause an allergic skin reaction. |
| H400 | Very toxic to aquatic life. |
Precautionary statements: P201, P261, P270, P272, P273, P280, P301, P305, P308, P310, P312, P313, P330, P333, P338, P391, P501
03 · Physical and chemical properties
1,4-dihydroxybenzene 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 | 285 °C (545 °F) | NIOSH | |
| 287 °C (548.6 °F) | ICSC | ||
| Melting point | 173 °C (343.4 °F) | HSDB | |
| 170 °C (338 °F) | NIOSH | ||
| 172 °C (341.6 °F) | ICSC | ||
| Density | 1.33 g/cm³ | NIOSH | |
| 1.3 g/cm³ | ICSC | ||
| 1.33 g/cm³ | at 20 °C | HSDB | |
| Solubility | In water, 72,000 mg/L at 25 °C | at 25 °C | HSDB |
| 7% soluble in water at 25 °C | at 25 °C | HSDB | |
| Vapor pressure | 0.00001 mmHg | NIOSH | |
| 0.0009001 mmHg | at 20 °C | ICSC | |
| 0.000019 mmHg | at 25 °C | HSDB | |
| Flash point | 165 °C (329 °F) | HSDB | |
| 165 °C (329 °F) | Closed cup | HSDB | |
| Autoignition temperature | 515.56 °C (960 °F) | HSDB | |
| 515 °C (959 °F) | ICSC | ||
| Lower explosive limit (LEL) | Dust cloud may explode if ignited in an enclosed area. | HSDB | |
| Combustible Solid; dust cloud may explode if ignited in an enclosed area. | NIOSH | ||
| Potentially explosive reaction with oxygen at 90 °C/ 100 bar...Slight explosion hazard when exposed to heat. | at 90 °C, at 75006.2 mmHg | HSDB | |
| Vapor density | 3.81 (air = 1) | HSDB | |
| 3.8 (air = 1) | ICSC | ||
| Critical temperature and pressure | 549 °C (1020.2 °F) | HSDB |
Values compiled from PubChem Laboratory Chemical Safety Summary. Temperatures converted to Fahrenheit for reference.
04 · Source notes
Further notes on 1,4-dihydroxybenzene
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
In water, 6.72 g/L at 20 °C. Also water solubility = 3.85 g/L at 0 °C; 5.12 g/L at 10 °C; 5.40 g/L at 15 °C; 8.76 g/L at 30 °C; 11.5 g/L at 40 °C; 25/9 g/L at 60 °C; 46.8 g/L at 80 °C; 66.4 g/L at 100 °C
Source: HSDB
05 · Handling and storage
Storing and handling 1,4-dihydroxybenzene
Storage conditions
Keep well closed and protected from light.
Source: Hazardous Substances Data Bank (HSDB)
Incompatible materials
Strong oxidizers, alkalis.
Source: Hazardous Substances Data Bank (HSDB)
Reactivity
HYDROQUINONE is a slight explosion hazard when exposed to heat. Incompatible with strong oxidizing agents. Also incompatible with bases. It reacts with oxygen and sodium hydroxide. Reacts with ferric salts (NTP, 1992). Hot and/or concentrated NaOH can cause hydroquinone to decompose exothermically at elevated temperature. (NFPA Pub. 491M, 1975, 385)
Source: CAMEO Chemicals
Planning storage for a mix of chemicals? Check 1,4-dihydroxybenzene in the storage compatibility matrix →