Flame retardant product and process

A method of producing a flame retardant of general formula (I):

• ##STR7## in which R is independently selected from the group consisting of linear, branched or cyclic alkyl, alkenyl, and provided that R bonded to the cyclic phosphorus atom is not alkoxy, alkoxyl, R' is selected from the group consisting of linear, branched or cyclic alkyl, alkenyl, alkaryl, aryl, aralkyl, haloaryl, aryloxyalkyl, haloaryloxyalkyl, and hydroxyalkyl, m is 0, 1 or 2, n is 1, 2 or 3 and (n+m) is 3
• wherein said method comprises a first step and a second step, and optionally a third step,
• said first step comprising:
• (a) reacting a bicyclic phosphite of general formula (II):
• ##STR8## wherein said R' is as hereinabove defined, with an acid selected from the group consisting of phosphorous acid, phosphoric acid, hypophosphorous acid, phosphonic acid and derivatives or salts thereof, in a molar ratio sufficient to produce a phosphite of general formula (III):
• ##STR9## wherein said R', n and m are as hereinabove defined, and each X is independently selected from the group consisting of H, OH, alkyl, alkenyl, and alkoxy, and mixtures thereof
• and said second step comprising:
• (b) reacting said phosphite (III) with an alkene or alkyne selected from the group consisting of linear, branched or cyclic alkenes or alkynes, and substituted alkenes or alkynes which have at least one .alpha.-unsaturated bond, in the presence of a free radical initiator to produce said flame retardant of general formula (I)
• and said optional third step comprising:
• (c) purifying said flame retardant.