Patent ID: 7626051

Claim:
A method for preparing a biphenylphosphonate compound of the following formula (I): wherein n is 2 or 3; Ar is a C 6 -C 16 aromatic group; which comprising: (a) reacting o-phenylphenol with phosphorus trichloride in the presence of zinc chloride catalyst to form a 6-chloro-6H-dibenz [c,e] [1,2]oxaphosphorin of the following formula (II); (b′) oxidizing the compound of formula (II) in the presence of water and ozone to form a 6-chloro-6-oxide-dibenz [c,e] [1,2]oxaphosphorin of the following formula (V); and (c′) reacting a polyhydroxybenzene compound of the following formula (III) (HO) n —Ar (III) wherein, n and Ar are defined the same as the above, with the compound of formula (V) to form the compound of formula (I).