Tetraphenylarsonium chloride explained

Tetraphenylarsonium chloride is the organoarsenic compound with the formula (C₆H₅)₄AsCl. This white solid is the chloride salt of the tetraphenylarsonium cation, which is tetrahedral. Typical of related quat salts, it is soluble in polar organic solvents. It often is used as a hydrate.

Synthesis and reactions

It is prepared by neutralization of tetraphenylarsonium chloride hydrochloride, which is produced from triphenylarsine:^[1]

(C₆H₅)₃As + Br₂ → (C₆H₅)₃AsBr₂

(C₆H₅)₃AsBr₂ + H₂O → (C₆H₅)₃AsO + 2 HBr

(C₆H₅)₃AsO + C₆H₅MgBr → (C₆H₅)₄AsOMgBr

(C₆H₅)₄AsOMgBr + 3 HCl → (C₆H₅)₄AsCl^.HCl + MgBrCl

(C₆H₅)₄AsCl^.HCl + NaOH → (C₆H₅)₄AsCl + NaCl + H₂O

Like other quat salts, it is used to solubilize polyatomic anions in organic media.^[2] To this end, aqueous or methanolic solutions containing the anion of interest are treated with a solution of tetraphenylarsonium chloride, typically resulting in precipitation of the tetraphenylarsonium anion salt.

Related compounds

• Tetraphenylphosphonium chloride
• Tetrabutylammonium chloride
• Tetraethylammonium chloride

Notes and References

1. 10.15227/orgsyn.030.0095. Tetraphenylarsonium Chloride Hydrochloride. Organic Syntheses. 1950. 30. 95. R. L.. Shriner. Calvin N.. Wolf.
2. Book: 10.1002/9780470132470.ch36. Tetraethylammonium, Tetraphenylarsonium, and Ammonium Cyanates and Cyanides. 1976. 16. Dieck. R. L.. Peterson. E. J.. Galliart. A.. Brown. T. M.. Moeller. T.. Inorganic Syntheses. 131–137. 9780470132470.