HazMat Tool — substance information

Ethyl orthoformate

HMT 15 June 2026
Reference only — HMT snapshot for inspection and audit support; not a shipping paper, placard mandate, or CVI record. Use Print / PDF below for field notes.
UN / ID
UN 2524
Hazard class
3
Packing group
III
ERG guide
ERG 129
Special provisions
SP B1, SP IB3, SP T2, SP TP1
Source
49 CFR §172 (15 June 2026)

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Ethyl orthoformate


Triethyl orthoformate is an organic compound with the formula HC(OC2H5)3. This colorless volatile liquid, the ortho ester of formic acid, is commercially available. The industrial synthesis is from hydrogen cyanide and ethanol. It may also be prepared from the reaction of sodium ethoxide, formed in-situ from sodium and absolute ethanol, and chloroform: CHCl3 + 3 Na + 3 EtOH → HC(OEt)3 + 3⁄2 H2 + 3 NaCl Triethyl orthoformate is used in the Bodroux–Chichibabin aldehyde synthesis, for example: RMgBr + HC(OC2H5)3 → RC(H)(OC2H5)2 + MgBr(OC2H5) RC(H)(OC2H5)2 + H2O → RCHO + 2 C2H5OH In coordination chemistry, it is used to convert metal aquo complexes to the corresponding ethanol complexes: (BF4)2 + 6 HC(OC2H5)3 → (BF4)2 + 6 HC(O)(OC2H5) + 6 HOC2H5 Triethyl orthoformate (TEOF) is an excellent reagent for converting compatible carboxylic acids to ethyl esters Wikipedia

Emergency Response Guide No. 129

Hazardous Materials Table

Source: 49 CFR §172 (15 June 2026)

(3) Hazard Class

3
Flammable liquids

(4) Identification number Help

UN 2524

(5) Packing Group Help

III

(6) Labels Help

Flammable liquids (3)

(7) Special Provisions (§172.102) Help

×Note:
Special provisions may be very complex. The extracts are taken from 49 CFR §172.102. Please be careful with the information, as necessary, additional conditions may be applied that are not written here. Please check the original source and report bugs.
B1
IB3
T2
TP1

(8) Packing Authorizations (§173.***) Help

(8A) Exceptions150see 49 CFR §173.150
(8B) Non-bulk203see 49 CFR §173.203
(8C) Bulk242see 49 CFR §173.242

(9) Quantity Limits Help

(9A) Passenger aircraft/rail60 L
(9B) Cargo aircraft only220 L

(10) Vessel stowage Help

(10A) Location
(10B) Other n/a

Segregation chart for load, transport, and storage

This chart shows whether loading, transport, or storage with other hazard classes is permitted, prohibited, or restricted. Based on 49 CFR §177.848.

Prohibited Must not be loaded, transported, or stored together in the same vehicle or facility.
Permitted May be loaded, transported, or stored together.
Restricted May be loaded, transported, or stored together only with restrictions.