Nomenclature
CAS number: 121-43-7
Boric acid trimethyl ester; methyl borate.
C
3H
9BO
3; mol wt 103.91.
C 34.68%, H 8.73%, B 10.40%, O 46.19%.
B(OCH
3)
3.
Description and references
Prepn from pyridine-boron trichloride complex:
Gerrard, Lappert, Chem. Ind. (London) 1952, 53; from methanol and boric oxide, borax or boric
acid: Schlesinger, J. Am. Chem. Soc. 75, 213 (1953); from methyl orthosilicates and boron
halide: Wiberg, Krüerke, Z. Naturforsch. 8b, 608 (1953); from boric acid and methanol: Steinberg,
Hunter, Ind. Eng. Chem. 49, 174 (1957). Several mfg processes: US 2689259; US 2884439; US 2937195 (to Callery Chem.); US 2880227 and US 2884440 (to Olin Mathieson); US 2855427 (to Am. Potash & Chem.); US 2739979 (to USAEC). Acute toxicity: H. F. Smyth et al., Am. Ind. Hyg. Assoc. J. 23, 95 (1962).
Properties
Liquid, d 0.915. bp 67-68°. Flash pt 29°C (84.2°F). Flammable. Miscible with tetrahydrofuran,
ether, isopropylamine, hexane, methanol, Nujol and other organic liquids.
Stable in the absence of moisture, but hydrolyzes in the presence
of water to methanol and boric acid. Forms an azeotrope with methanol:
70% B(OCH3)3 +30% methanol, d 0.87; bp 52-54°; flash pt 34°C (93.2°F). LD50 orally in rats: 6.14 ml/kg (Smyth).Use
As solvent for waxes, resins, oils; catalyst in
the manuf of ketones; analysis of paint and varnish ingredients; as
neutron detector gas in the presence of a scintillation counter; as
a promoter of diborane reactions.