Condensation polymerization catalyst for carbonate produced by transesterification method. It is also used for the determination of potassium, sodium and chlorine-containing organic compounds, such as the analysis of potassium in fertilizers and blood. Gravimetric and titrimetric determination of potassium. Association precipitation of large cations such as alkaloids and quaternary ammonium salts. Sodium tetraphenylborate is a cheap and sensitive reagent for detecting potassium. In neutral, alkaline or acetic acid solutions, sodium tetraphenylborate will react quantitatively with potassium ions to form a white precipitate of potassium tetraphenylborate that is insoluble in water: K(+) + [B(C6H5)4](-) → K[B(C6H5)4]↓ (+ and - signs in brackets indicate charge)

The detection limit of the reaction is 1μg, and the minimum concentration of potassium ions is 2μg/mL. Ammonium ions, rubidium ions, and cesium ions will also generate similar precipitates. Generally, ammonium ions need to be removed by burning in advance (because the ammonium salt is unstable and easy to decompose when burning). Rubidium ions and cesium ions can also be preliminarily removed by precipitation. Remove.

Another commonly used reagent for identifying potassium ions is sodium cobalt nitrite, which can produce a yellow crystal precipitate with potassium ions. Its main interfering ions are also ammonium ions. In acetonitrile solution, sodium tetraphenylborate reacts with acyl chloride and tertiary amine, and sodium chloride precipitates out to obtain N-acyl quaternary ammonium salt:

RC(O)Cl + R3'N + NaBPh4 → [RC (O)NR3'][BPh4] + NaCl

Sodium tetraphenylborate can be used as a phenyl donor to cross-couple with vinyl ester or aryl triflate under palladium catalysis. Derivatives of aryl alkenes or biphenyl are produced in high yields. Sodium tetraphenylborate has high solubility in non-polar solvents and is easy to crystallize, so it can be used to prepare and separate some organometallic complexes.