UN/NA Number Reference

UN 2698: Tetrahydrophthalic anhydrides

49 CFR 172.101 Hazardous Materials Table·ERG 2024

DOT Classification and Shipping

UN 2698 is assigned the proper shipping name Tetrahydrophthalic anhydrides in the U.S. DOT Hazardous Materials Table (49 CFR 172.101). It is classified as a Class 8 Corrosive material, Packing Group III. Required label(s): 8.

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 156)

Hazards: TOXIC or CORROSIVE. FLAMMABLE. Vapors may travel to ignition source.

Fire: Alcohol-resistant foam, dry chemical, CO2. Water spray for cooling only.

Spill: Eliminate ignition sources. Do not touch. Ventilate area.

Chemical and Physical Properties

Memtetrahydrophthalic anhydride is a clear colorless to light yellow slight viscous liquid. Highly toxic and a strong irritant to skin, eyes and mucous membranes. Corrosive to skin and metal. Used in making polyester, alkyd resins, and plasticizers.

CAS Number: 85-43-8

Molecular Formula: C8H8O3

Molecular Weight: 152.15 g/mol

Color / Form: White crystalline powder

Boiling Point: at 6.7kPa: 195Â C

Melting Point: Crystals from petroleum ether. MP: 103.5 °C. Soluble in ethanol, acetone, chloroform, benzene; slightly soluble in petroleum ether. /cis-1,2,3,6-Tetrahydrophthalic anhydride/

Flash Point: 315 F (157 C) Open cup

Autoignition: 450 °C

Specific Gravity: 1.20 (sinks in water)

Vapor Pressure: 0.05 [mmHg]

Vapor Density: 5.3 (heavier than air)

Water Solubility: Slightly soluble in petroleum ether and ethyl ether

Special Provisions

49 CFR 172.102 special provision codes for this entry: 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.