Patent ID: 7888534

Claim:
A method for preparing an optionally substituted diaryl alkylphosphonate comprising: heating an optionally substituted triarylphosphite to a temperature of from about 210° C. to about 260° C.; adding to the heated optionally substituted triarylphosphite a mixture comprising: (i) an optionally substituted trialkylphosphite in a molar excess of from at least 10% to about 50% of the optionally substituted triarylphosphite and further a catalyst; or (ii) an optionally substituted alkanol in a molar excess of from at least 10% to about 50% of the optionally substituted triarylphosphite and further a catalyst; and reacting the mixture and the heated optionally substituted triarylphosphite to form the optionally substituted diaryl alkylphosphonate wherein the optionally substituted diaryl alkylphosphonate contains less than 1% total product residual triarylphosphite.