Organometallic Compounds
REACH
Trimethyl borate
CAS Number
121-43-7
EC Number
204-468-9
Abbreviation
TMB
What is Trimethyl borate?
Trimethyl borate (CAS 121-43-7), also referred to as TMB, is a boron-containing ester used as a reactive intermediate and functional additive in chemical manufacturing.
Where is Trimethyl borate used?
- Synthesis: boron source and flame retardant precursor
- Polymer and plastics: flame retardant additive and thermal stabilizer
- Pharmaceutical and fine chemical: reagent in borylation reactions and precursor to boronic acid derivatives
- Agrochemical production: boron donor in the synthesis of active ingredients and micronutrient formulations targeting boron-deficient crops
- Textile and paper processing: biocidal and pH-buffering agent applied during treatment baths and finishing stages
- It also serves as a stabilizing agent in polymer and agrochemical formulations.
Good to know: Buyers should confirm moisture sensitivity requirements with suppliers, as grade selection affects handling and storage conditions.
Commercial specifications
- Purity levels commonly range from 97% to 99%+
- Typically in drum and IBC packaging suited for industrial volumes
Other Names (Synonyms)
boric acid, trimethyl ester|B(OMe)3|B(OCH3)3|(MeO)3B|Methyl borate|Borester O|Boric acid (H3BO3), trimethyl ester|Methyl borate ((MeO)3B)|TMB
What are the physical properties of Trimethyl borate?
Melting Point -29.3 °C
Boiling Point 67-68 °C
Density 0.915 g/cm³
Flash Point 8 °F
Appearance Water-white liquid. Miscible with ether, methanol, hexane, tetrahydrofuran; decomposes in presence of water.
Color Colorless
Form Liquid
Water Solubility reacts
Vapor Pressure 147.9-148 hPa ( 20 °C)
Refractive Index n 20/D 1.358(lit.)
How is Trimethyl borate classified and handled safely? Learn More
Danger
GHS02· Flammable GHS07· Irritant GHS08· Health Hazard GHS06· Toxic
Hazard Statements
H225 Highly Flammable liquid and vapor
H226 Flammable liquid and vapor
H301 Toxic if swallowed
H302 Harmful if swallowed
Precautionary Statements
P203 Obtain, consult and follow expert instructions for use.
P210 Keep away from heat, hot surfaces, sparks, open flames and other ignition sources. No smoking.
P233 Keep container tightly closed.
P240 Ground and bond container and receiving equipment.
Which trade and regulatory codes apply to Trimethyl borate?
HS Code 29209085
UN Number 2416
ADR Class 3
Packing Group II
WGK (Germany) 3