1068. Benzeneboronic Acid

Nomenclature

CAS number: 98-80-6
Phenylboronic acid; phenylboric acid; phenylboron dihydroxide.
C6H7BO2; mol wt 121.93.
C 59.10%, H 5.79%, B 8.87%, O 26.24%.

Description and references

Prepd by the reaction of phenylmagnesium bromide with methyl borate: Washburn et al. in Adv. Chem. Ser. 23, entitled “Metal-Organic Compounds,” M. Sittig, Ed. (ACS, Washington DC, 1959) pp 102-128. Crystal and molecular structure: S. J. Rettig, J. Trotter, Can. J. Chem. 55, 3071 (1977).

Chemical structure

Properties

Crystals from water. Spontaneous conversion to C6H5BO, benzene boronic anhydride or phenylboroxide on standing in dry air, although the best method is by azeotropic dehydration with toluene. mp 215-216° (anhydride). pKa 13.7. Dipole moment 1.72 (dioxane). Soly in water at 25°: 2.5%, benzene: 1.75%, xylene: 1.2%, ether: 30.2%, methanol: 178%.