Hydrogen Bromide → Phosphonic acid, p-phenylenedi-

Participants

Reaction Conditions

Reaction Steps

93 ml of HBr at 33% by weight in acetic acid are added to 6.68 g of 1.4-benzene-diphosphonic acid tetra-ethyl ester and the mixture is heated to 80° C. for 4 hours. After cooling to ambient temperature 200 ml of diethyl-ether are added and the mixture, after brief agitation, is cooled to -78° C. in a bath of ethanol and dry ice. The oily precipitate obtained is recovered by decantation and subjected twice more to the dispersion process with ether and low-temperature precipitation. The oily residue obtained is vacuum dried (1 mm Hg) at 50° C. for 8 hours, obtaining 4.0 g of 1,4-benzene-diphosphonic acid in the form of a white solid. Yield in moles 89%.

Provenance & Evidence