5 diphenylphosphine oxide 1 4 hydroquinone was formed the latter bisphenol was concentrated to one third volume by treating with acetone the concentrated product was then recrystallized from ethanol water to produce the desired product the structure was confirmed by 1 h and 13 c nmr d 6 dmso testing into a 100 cc single neck round bottom flask equipped with a magnetic stir bar was placed 4 5 g 14 5 mmols of 2 5 dihydroxyphenyldiphenylphosphine oxide along with 6 0 g of sodium sulfate 3 6 g 15 5 moles of silver oxide and 60 ml of acetone the reaction mixture was stirred at room temperature for 17 hours followed by filtration and removal of the acetone to give 4 5 g of a brown sticky solid 1 h nmr cdcl 3 study showed that 2 diphenylphosphine oxide 1 4 benzoquinone was formed to 1 54 g 5 mmols of the benzoquinone above in raw form was added 1 0 g 5 mmols of diphenylphosphine oxide dissolved in 20 ml of toluene after stirring for about 5 minutes at room temperature a tan precipitate was formed stirring was continued for 1 5 hours at which time the product was filtered and washed with toluene and dried to produce 2 12 g of bis 2 5 diphenylphosphine oxide 1 4 hydroquinone which was shown to be pure by 1 h nmr study homologs of the bisphosphine oxide monomers prepared above may be prepared from additional precursor quinones they too would make suitable comonomers for flame retardant polycarbonates and polyesters thereof moreover the above bisphosphine oxide monomers and homologs thereof would be useful for.