Substance profile
Methenamine
Methenamine is crystallizes from ethanol as colorless, hygroscopic rhombododecahedra and is odorless.
01 · Identification
What Methenamine is
Methenamine is crystallizes from ethanol as colorless, hygroscopic rhombododecahedra and is odorless. Its molecular formula is C6H12N4 and its molecular weight is 140.19 g/mol. It melts at 129 °C.
Under the GHS it carries the signal word Warning.
Other names for Methenamine
- hexamethylenetetramine
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.
03 · Physical and chemical properties
Methenamine 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 | Sublimes (NTP, 1992) | sublimes | CAMEO |
| Melting point | 128.5 °C (263.3 °F) | range, midpoint shown | HSDB |
| 260 °C (500 °F) | approximate | HSDB | |
| 190 °C (374 °F) | approximate | HSDB | |
| Density | 1.3394 g/cm³ | at 22 °C | HSDB |
| 1.35 g/cm³ | at 20 °C | CAMEO | |
| 1.27 g/cm³ | at 25 °C | HSDB | |
| Solubility | Freely soluble in water; practically insoluble in petroleum ether | HSDB | |
| In water, 302,300 mg/L at 25 °C | at 25 °C | HSDB | |
| Vapor pressure | 0.00061 mmHg | at 25 °C | HSDB |
| 0.004 mmHg | Haz-Map | ||
| Flash point | 250 °C (482 °F) | HSDB | |
| Autoignition temperature | 390 °C (734 °F) | ICSC | |
| 371.11 °C (700 °F) | above this value | CAMEO | |
| Lower explosive limit (LEL) | Dust explosion possible if in powder or granular form, mixed with air. | HSDB | |
| Vapor density | 4.9 (air = 1) | HSDB | |
| Critical temperature and pressure | 563.85 °C (1046.9 °F) | HSDB |
Values compiled from PubChem Laboratory Chemical Safety Summary. Temperatures converted to Fahrenheit for reference.
04 · Source notes
Further notes on Methenamine
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
Solubility of methenamine in 100 g of various solvents at 20 °C is: 13.4 g chloroform, 7.25 g in methanol, 2.89 g in absolute ethanol, 0.65 g in acetone, 0.23 g in benzene, 0.14 g in xylene, 0.06 g in ether, and near zero in petroleum ether.
Source: HSDB
05 · Handling and storage
Storing and handling Methenamine
Storage conditions
Keep container tightly closed in a dry and well-ventilated place. Hygroscopic. Storage class (TRGS 510): Flammable solid hazardous materials
Source: Hazardous Substances Data Bank (HSDB)
Incompatible materials
Incompatible materials: Strong acids, acids, strong oxidizing agents
Source: Hazardous Substances Data Bank (HSDB)
Reactivity
HEXAMETHYLENETETRAMINE is hygroscopic. It is sensitive to exposure to heat. This chemical is incompatible with oxidizing agents. It is also incompatible with acids. It reacts violently with sodium peroxide. It reacts explosively with 1-bromopentaborane(9) at temperatures above 194 °F. The complex with iodine deflagrates at 280 °F. The 1:1 addition complex with iodoform has exploded at 352 °F. It is corrosive to some metals, such as aluminum and zinc (NTP, 1992). Special Hazards of Combustion Products: Formaldehyde gas and ammonia may be given off when hot (USCG, 1999).
Source: CAMEO Chemicals
Planning storage for a mix of chemicals? Check Methenamine in the storage compatibility matrix →