Ethyl orthoformate
HMT 15 June 2026Ethyl 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 Class3Flammable liquids |
(4) Identification number |
(5) Packing Group |
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(6) Labels |
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(7) Special Provisions (§172.102)
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| B1 | |
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| IB3 | |
| T2 | |
| TP1 |
(8) Packing Authorizations (§173.***) 
| (8A) Exceptions | 150 | see 49 CFR §173.150 |
|---|---|---|
| (8B) Non-bulk | 203 | see 49 CFR §173.203 |
| (8C) Bulk | 242 | see 49 CFR §173.242 |
(9) Quantity Limits 
| (9A) Passenger aircraft/rail | 60 L |
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| (9B) Cargo aircraft only | 220 L |
(10) Vessel stowage 
| (10A) Location | |
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| (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.
| Hazard class | 8![]() | 7![]() | 6.1![]() | 5.2![]() | 5.1![]() | 4.3![]() | 4.2![]() | 4.1![]() | 3![]() | 2.3B![]() | 2.3A![]() | 2.2![]() | 2.1![]() | 1.6![]() | 1.5![]() | 1.4![]() | 1.3![]() | 1.1/1.2![]() |
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| Must not be loaded, transported, or stored together in the same vehicle or facility. | |
| May be loaded, transported, or stored together. | |
| May be loaded, transported, or stored together only with restrictions. |
