Trimethyl borate is the organoboron compound with the formula B(OCH3)3. It is a colourless liquid that burns with a green flame.[1] It is an intermediate in the preparation of sodium borohydride and is a popular reagent in organic chemistry. It is a weak Lewis acid (AN = 23, Gutmann-Beckett method).[2]
This chemical is quite flammable and burns with a green flame
Borate esters are prepared by heating boric acid or related boron oxides with alcohols under conditions where water is removed by azeotropic distillation. [1]
Applications
Trimethyl borate is the main precursor to sodium borohydride by its reaction with sodium hydride in the Brown-Schlesinger process:
4 NaH + B(OCH3)3 → NaBH4 + 3 NaOCH3
It is a gaseous anti-oxidant in brazing and solder flux. Otherwise, trimethyl borate has no announced commercial applications. It has been explored as a fire retardant, as well as being examined as an additive to some polymers.[1]
Organic synthesis
It is a useful reagent in organic synthesis, as a precursor to boronic acids, which are used in Suzuki couplings. These boronic acids are prepared via reaction of the trimethyl borate with Grignard reagents followed by hydrolysis:.[3][4]
↑Beckett, M. A.; Strickland, G. C.; Holland, J. R.; Varma, K. S. (September 1996). "A convenient n.m.r. method for the measurement of Lewis acidity at boron centres: correlation of reaction rates of Lewis acid initiated epoxide polymerizations with Lewis acidity". Polymer. 37 (20): 4629–4631. doi:10.1016/0032-3861(96)00323-0.
