UN/NA Number Reference
DOT Class 4.1 Flammable Solid placard

UN 1328: Hexamethylenetetramine

49 CFR 172.101 Hazardous Materials Table·ERG 2024

DOT Classification and Shipping

UN 1328 is assigned the proper shipping name Hexamethylenetetramine in the U.S. DOT Hazardous Materials Table (49 CFR 172.101). It is classified as a Class 4.1 Flammable Solid material, Packing Group III. Required label(s): 4.1.

Packing group indicates the degree of danger within a hazard class: PG I is high danger, PG II medium, PG III low. The proper shipping name, hazard class, UN number, and packing group together form the basic shipping description that must appear on shipping papers and, where required, on the package and placard.

Emergency Response (ERG Guide 133)

Hazards: Flammable. May be ignited by friction, heat, sparks. May burn rapidly with flare-burning effect.

Fire: Water spray, foam, dry chemical. Some may be extinguished with CO2.

Spill: Eliminate ignition sources. Do not touch. Cover with dry earth, sand, or non-combustible material.

Chemical and Physical Properties

Hexamethylenetetramine appears as odorless white crystalline powder or colorless lustrous crystals. Sublimes in a vacuum at about 505 °F with some decomposition. Solutions are strong bases (pH of 0.2 molar aqueous solution is 8.4). (NTP, 1992)

CAS Number: 100-97-0
Molecular Formula: C6H12N4
Molecular Weight: 140.19 g/mol
Color / Form: Crystallizes from ethanol as colorless, hygroscopic rhombododecahedra.
Odor: Odorless
Boiling Point: Sublimes
Melting Point: 536 °F (sublimes) (NTP, 1992)
Flash Point: 482 F
Autoignition: greater than 700 °F (NTP, 1992)
Specific Gravity: 1.35 (sinks in water)
Vapor Pressure: 0.004 [mmHg]
Vapor Density: 4.9 (heavier than air)
Water Solubility: greater than or equal to 100 mg/mL at 68 F
Log P: log Kow = -2.18 at pH 7-9, 20 °C
pH: pH of 0.2 molar aqueous solution: 8.4

Special Provisions

49 CFR 172.102 special provision codes for this entry: A1, IB8, IP3, T1, TP33. These codes modify the general requirements (packaging, quantity limits, exceptions) for this specific material. Look up each code in 49 CFR 172.102 for the full text.

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Reference data compiled from the DOT Hazardous Materials Table (49 CFR 172.101), the 2024 Emergency Response Guidebook, and public chemical databases (PubChem, NIOSH, EPA). Always verify the correct shipping description against the current regulation and the manufacturer's SDS Section 14 before shipping.