Substance profile
Naphthalene
Naphthalene is white crystalline flakes Plates from ethanol with an aromatic odor.
01 · Identification
What Naphthalene is
Naphthalene is white crystalline flakes Plates from ethanol with an aromatic odor. Its molecular formula is C10H8 and its molecular weight is 128.17 g/mol. It boils at 218 °C, melts at 80.2 °C.
Under the GHS it carries the signal word Warning. It is classed as hazardous Air Pollutants (HAPs).
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>. |
| H302 | Harmful if swallowed. |
| H400 | Very toxic to aquatic life. |
| H410 | Very toxic to aquatic life with long lasting effects. |
Precautionary statements: P201, P270, P273, P280, P301, P308, P312, P313, P330, P391, P501
03 · Physical and chemical properties
Naphthalene 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 | 217.9 °C (424.2 °F) | HSDB | |
| 217.78 °C (424 °F) | NIOSH | ||
| 217.78 °C (424 °F) | at 760 mmHg | CAMEO | |
| Melting point | 80.2 °C (176.4 °F) | HSDB | |
| 80 °C (176 °F) | NIOSH | ||
| 80.22 °C (176.4 °F) | CAMEO | ||
| Density | 1.15 g/cm³ | NIOSH | |
| 1.162 g/cm³ | at 20 °C | HSDB | |
| Solubility | 0.003% | NIOSH | |
| In water, 31 mg/L at 25 °C | at 25 °C | HSDB | |
| Vapor pressure | 0.08 mmHg | NIOSH | |
| 0.05 mmHg | at 20 °C | CAMEO | |
| 0.085 mmHg | at 25 °C | HSDB | |
| Flash point | 79 °C (174.2 °F) | Closed cup | HSDB |
| 78.89 °C (174 °F) | NIOSH | ||
| 87.78 °C (190 °F) | CAMEO | ||
| Autoignition temperature | 526.11 °C (979 °F) | HSDB | |
| 540 °C (1004 °F) | ICSC | ||
| Lower explosive limit (LEL) | 0.9 % by volume | HSDB | |
| Upper explosive limit (UEL) | 5.9 % by volume | HSDB | |
| Vapor density | 4.42 (air = 1) | HSDB | |
| Odor threshold | Odor detection in water 6.80 ppm (purity not specified) | HSDB | |
| At least as low as 0.3 ppm. | HSDB | ||
| Odor threshold (water) 0.021 mg/L (w/v); odor threshold (air) 0.084 ppm (v/v) | HSDB | ||
| Critical temperature and pressure | 475.22 °C (887.4 °F) | HSDB | |
| Critical pressure: 588 PSI = 40.0 atm = 4.05 megaNewtons/sq m | HSDB | ||
| Corrosivity | Melted naphthalene will attack some forms of plastics, rubber, and coatings. | HSDB |
Values compiled from PubChem Laboratory Chemical Safety Summary. Temperatures converted to Fahrenheit for reference.
04 · Source notes
Further notes on Naphthalene
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
1 g/13 mL ethanol or methanol; 1 g/3.5 mL benzene or toluene; 1 g/8 mL olive oil or tupentine; 1 g/2 mL chloroform or carbon tetrachloride; 1 g/1.2 mL carbon disulfide. Very soluble in ether, hydronaphthalenes, and in fixed and volatile oils.
Source: HSDB
05 · Handling and storage
Storing and handling Naphthalene
Storage conditions
Without inert-gas blanketing and at the temperature normally used for the storage of molten naphthalene, i.e., 90 °C, the vapors above the liquid are within the flammability limits. Thus, storage tanks containing molten naphthalene have a combustible mixture in the vapor space and care must be taken to eliminate all sources of ignition around such systems. Naphthalene dust can form explosive mixtures with air which necessitates the design and operation of solid handling systems.
Source: Hazardous Substances Data Bank (HSDB)
Incompatible materials
Naphthalene ...will react violently with chromic anhydride.
Source: Hazardous Substances Data Bank (HSDB)
Reactivity
Vigorous reactions, sometimes amounting to explosions, can result from the contact between aromatic hydrocarbons, such as NAPHTHALENE, and strong oxidizing agents. They can react exothermically with bases and with diazo compounds. Substitution at the benzene nucleus occurs by halogenation (acid catalyst), nitration, sulfonation, and the Friedel-Crafts reaction. Naphthalene, camphor, glycerol, or turpentine will react violently with chromic anhydride [Haz. Chem. Data 1967. p 68]. Friedel-Crafts acylation of naphthalene using benzoyl chloride, catalyzed by AlCl3, must be conducted above the melting point of the mixture, or the reaction may be violent [Clar, E. et al., Tetrahedron, 1974, 30, 3296].
Source: CAMEO Chemicals
Planning storage for a mix of chemicals? Check Naphthalene in the storage compatibility matrix →