of the present invention str7 the mixture is then isolated purified and stabilized the foregoing reactions generally proceed quite readily and usually no special reaction conditions or chemical processing equipment need be employed these reactions can be conducted at room temperature at temperatures above ambient or at temperatures below ambient elevated temperatures may be used to ensure completion of the reaction although some of the foregoing condition reactions are quite exothermic and it may be advisable at least initially to provide external cooling it may be preferable although not essential to employ solvents such as halogenated hydrocarbon solvents e g methylene chloride and chlorobenzene while the presence of a catalyst is generally not required catalysts may decrease reaction times and allow the use of lower reaction temperatures in particular the final step of reacting the halogenated phosphorous monoester with ethylene oxide is facilitated by using a small but catalytically effective amount of titanium tetrachloride or other catalysts such as tin tetrachloride or magnesium chloride after the halogenated phosphorous monoester is completely reacted with ethylene oxide to form the mixture of this invention the mixture is then isolated purified and stabilized isolation and purification may be carried out by washing with water aqueous ammonia or the like adjusting the ph to a consistent value in the range of about 9 10 and separating and recovering the low viscosity liquid product mixture by phase separation.