Triethyl borate

Not to be confused with triethylborane.
Triethyl borate
Triethyl borate molecule
Names
IUPAC name
Triethyl borate
Other names
Boron triethoxide
Boric acid, triethyl ester
Identifiers
3D model (JSmol)
ChEBI
ChemSpider
ECHA InfoCard 100.005.238 Edit this at Wikidata
EC Number
  • 205-760-9
UNII
  • InChI=1S/C6H15BO3/c1-4-8-7(9-5-2)10-6-3/h4-6H2,1-3H3 checkY
    Key: AJSTXXYNEIHPMD-UHFFFAOYSA-N checkY
  • InChI=1/C6H15BO3/c1-4-8-7(9-5-2)10-6-3/h4-6H2,1-3H3
    Key: AJSTXXYNEIHPMD-UHFFFAOYAB
  • O(B(OCC)OCC)CC
Properties
C6H15BO3
Molar mass 145.99 g·mol−1
Appearance clear liquid
Density 0.858 g/cm3
Melting point −85 °C (−121 °F; 188 K)
Boiling point 118 °C (244 °F; 391 K)
Hazards
Flash point 11 °C (52 °F; 284 K)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
☒N verify (what is checkY☒N ?)

Triethyl borate is a colorless liquid with the formula B(OCH2CH3)3. It is an ester of boric acid and ethanol. It has few applications.[1]

It is a weak Lewis acid (AN = 17 as measured by the Gutmann–Beckett method).[2] It burns with a green flame and solutions of it in ethanol are therefore used in special effects and pyrotechnics.

Green flame of triethyl borate
Video of triethyl borate burning (with intermittent blowing on it)

It is formed by the reaction of boric acid and ethanol in the presence of acid catalyst, where it forms according to the equilibrium reaction:

B(OH)3 + 3 C2H5OH ⇌ (C2H5O)3B + 3 H2O

In order to increase the rate of forward reaction, the formed water must be removed from reaction media by either azeotropic distillation or adsorption. It is used as a solvent and/or catalyst in preparation of synthetic waxes, resins, paints, and varnishes. It is used as a component of some flame retardants in textile industry and of some welding fluxes.

  1. ^ Robert J. Brotherton; C. Joseph Weber; Clarence R. Guibert; John L. Little (2000). "Boron Compounds". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. ISBN 978-3527306732.
  2. ^ M.A. Beckett, G.C. Strickland, J.R. Holland, and K.S. Varma, "A convenient NMR method for the measurement of Lewis acidity at boron centres: correlation of reaction rates of Lewis acid initiated epoxide polymerizations with Lewis acidity", Polymer, 1996, 37, 4629–4631. doi: 10.1016/0032-3861(96)00323-0