Improved synthesis of phosphorus-containing styrenic monomers

Abstract

Several dialkyl-p-vinylbenzyl phosphonates, for use in making fire-retardant styrenic and acrylic polymers, have been synthesised by reaction of p-vinylbenzyl chloride with various dialkyl phosphonates using the Michaelis-Becker reaction. This reaction is shown to have several benefits over the conventional Arbuzov methodology. Principal amongst these are that the Michaelis-Becker reaction proceeds rapidly at room temperature, or below, to give high yields of products requiring little or no purification, thus avoiding the heating necessary in the Arbuzov procedure, which can lead to premature thermal polymerization of the vinyl reactants and products. The Michaelis-Becker procedure is also shown to give ready access to higher dialkyl-p-vinylbenzyl phosphonates that would be difficult to obtain by the Arbuzov procedure.