Triethyl 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.^[1]

Triethyl orthoformate

Names
Preferred IUPAC name (Diethoxymethoxy)ethane
Other names Triethoxymethane; Ethyl orthoformate
Identifiers
CAS Number	122-51-0 Y
3D model (JSmol)	Interactive image
ChEMBL	ChEMBL1476236
ChemSpider	28955 N
ECHA InfoCard	100.004.138
EC Number	204-550-4
PubChem CID	31214
UNII	355LRR361Q
UN number	2524
CompTox Dashboard (EPA)	DTXSID8041957
InChI InChI=1S/C7H16O3/c1-4-8-7(9-5-2)10-6-3/h7H,4-6H2,1-3H3 N Key: GKASDNZWUGIAMG-UHFFFAOYSA-N N InChI=1/C7H16O3/c1-4-8-7(9-5-2)10-6-3/h7H,4-6H2,1-3H3 Key: GKASDNZWUGIAMG-UHFFFAOYAW
SMILES CCOC(OCC)OCC
Properties
Chemical formula	C7H16O3
Molar mass	148.202 g·mol−1
Density	0.891 g/mL
Melting point	−76 °C (−105 °F; 197 K)
Boiling point	146 °C (295 °F; 419 K)
Hazards
GHS labelling:
Pictograms
Signal word	Warning
Hazard statements	H226, H315, H319, H335
Precautionary statements	P210, P233, P240, P241, P242, P243, P261, P264, P271, P280, P302+P352, P303+P361+P353, P304+P340, P305+P351+P338, P312, P321, P332+P313, P337+P313, P362, P370+P378, P403+P233, P403+P235, P405, P501
Safety data sheet (SDS)	Fischer Scientific
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). N verify (what is YN ?) Infobox references

It may also be prepared from the reaction of sodium ethoxide, formed in-situ from sodium and absolute ethanol, and chloroform:^[2]

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:^[3]

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:^[4]

[Ni(H₂O)₆](BF₄)₂ + 6 HC(OC₂H₅)₃ → [Ni(C₂H₅OH)₆](BF₄)₂ + 6 HC(O)(OC₂H₅) + 6 HOC₂H₅

Triethyl orthoformate (TEOF) is an excellent reagent for converting compatible carboxylic acids to ethyl esters. Such carboxylic acids, refluxed neat in excess TEOF until low-boilers cease evolution, are quantitatively converted to the ethyl esters, without need for extraneous catalysis.^[5] Alternatively, added to ordinary esterifications using catalytic acid and ethanol, TEOF helps drive esterification to completion by converting the byproduct water formed to ethanol and ethyl formate.

See also

• Trimethyl orthoformate

References

1. Ashford's Dictionary of Industrial Chemicals, Third edition, 2011, page 9288
2. W. E. Kaufmann and E. E. Dreger (1941). "Ethyl orthoformate". Organic Syntheses; Collected Volumes, vol. 1, p. 258.
3. G. Bryant Bachman (1943). "n-Hexaldehyde". Organic Syntheses; Collected Volumes, vol. 2, p. 323.
4. Willem L. Driessen, Jan Reedijk "Solid Solvates: The Use of Weak Ligands in Coordination Chemistry" Inorg. Synth., 1992, Vol. 29,111–118. doi:10.1002/9780470132609.ch27
5. Paine, John B. (July 2008). "Esters of Pyromellitic Acid. Part I. Esters of Achiral Alcohols: Regioselective Synthesis of Partial and Mixed Pyromellitate Esters, Mechanism of Transesterification in the Quantitative Esterification of the Pyromellitate System Using Orthoformate Esters, and a Facile Synthesis of the Ortho Pyromellitate Diester Substitution Pattern". The Journal of Organic Chemistry. 73 (13): 4929–4938. doi:10.1021/jo800543w. ISSN 0022-3263. PMID 18522420.