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Description and features

Catonium MTPB (Methyltriphenylphosphonium Bromide) is white powder, its chemical formula is C19H18BrP. MTPB is a quaternary phosphonium salt mainly used in organic synthesis as a wittig reagent and as a phase transfer catalyst in the production of Powder Coatings. This material is highly soluble in water and polarizable solvents.

Methyltriphenylphosphonium Bromide is also known as MTPB, Triphenyl phosphate bromide and triphenylmethylphosphonium.

Compared to amines, imidazoles and quaternary ammonium salts CatOnium MTPB features considerable better latency and thermal stability. Further it offers a low odor, minimal color formation and controlled reactivity.


Europe and United States: Provided CatOnium MTPB is on stock in our local warehouses our lead time is about one week if delivered in 20 KG drums.

Canada,  South America,  South Africa and other markets can also be served, please contact our sales department for more details.

➔ Limited available in the European Union as this product has not been REACH registered (yet).

Product Identification

CAS number1779-49-3
EC number217-218-9
HS code2931 39 00


Appearance White crystal powder
Assay≥ 98.00 %
Ash≤ 0.30 %
Loss on drying ≤ 0.20 %
Triphenyl phosphine ≤ 0.50 %


CatOnium MTPB (Methyltriphenylphosphonium Bromide) is being used in: (powder) coatings.


Available packaging: 20 KG / 25 KG fiber drums.
Special packaging is available on request.


Store Methyltriphenylphosphonium bromide in a cool, dry and well-ventilated area and in line with legal requirements.
Keep MTPB away from heat sources and oxidizing agents.


A Material Safety Data Sheets (MSDS) is available for CatOnium BTBP and all other products supplied by Vesta Chemicals BV.

An MSDS describes the hazards of a product and explains how a product can be safely handled, used and stored. Besides it provides important regulatory and emergency response information for the purchased product.

Molecular and structural information

Molecular formulaC19H18BrP
Molecular weight357.22 g/mol
Smiles notation[Br-].C[P+](c1ccccc1)(c2ccccc2)c3ccccc3
Chemical formula phenylphosphonium bromide

Physicochemical information

Bulk density285 – 320 KG/m3
Flash point>240 ºC
Melting point230 – 234 °C
Log Kow-0.58
Solubility in water342 g/l @ 20 ºC
Vapor pressure 0.0000002 hPa

Methyltriphenylphosphonium Bromide | CAS: 1779-49-3 | Disclaimer. This information is supplied solely for informational purposes and Vesta Chemicals bv makes no guarantees or warranties, either expressed or implied, with respect to the accuracy and use of this data. All product warranties and guarantees shall be governed by the Standard Terms of Sale. Nothing in this document is legal advice or is a substitute for competent legal advice.