Trimethyl borate

Trimethyl borate (CAS 121-43-7) is an organoboron ester commercially known as Borester O and abbreviated as B(OMe)3 or (MeO)3B. It carries no assigned E-code and is classified under HS code 29209085. The compound is moisture-sensitive and handled under anhydrous conditions throughout its supply chain.

In pharmaceutical synthesis, trimethyl borate serves as a boron-transfer reagent and pH buffer, enabling controlled reaction environments during active ingredient manufacturing. In polymer and textile processing, it functions as a flame retardant and heat stabiliser by forming boron oxide char layers that interrupt combustion. Its antimicrobial activity also supports preservation applications in agricultural formulations.

Trimethyl borate is supplied in technical and synthesis grades as an anhydrous liquid. It falls under REACH registration requirements within the EU, and suppliers should confirm SDS compliance before procurement. Packaging is typically available in sealed metal drums or isotanks to prevent moisture ingress during storage and transport.