Diaryl alkylphosphonates and methods for preparing same
View Patent ↗A method for preparing substantially pure optionally substituted diaryl alkylphosphonates from an optionally substituted triarylphosphite and an optionally substituted trialkylphosphite or an optionally substituted alkanol under special reaction conditions is described.
1. 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.
2. The method of claim 1 , wherein the optionally substituted trialkylphosphite or optionally substituted alkanol is from at least about 20% to about 40% molar excess of the optionally substituted triarylphosphite.
3. The method of claim 1 , wherein the optionally substituted trialkylphosphite or optionally substituted alkanol is about 13% molar excess of the optionally substituted triarylphosphite.
4. The method of claim 1 , wherein the optionally substituted triarylphosphite is of general formula (III):
wherein R 1 is of general formula (II):
wherein R 3 , R 4 , R 5 , R 6 , and R 7 , independently, are selected from hydrogen, trifluoromethyl, nitro, cyano, C 1 -C 20 alkyl, an aromatic, a halide, C 1 -C 20 alkyl ether, benzyl halide, benzylether, aromatic ether and combinations thereof.
5. The method of claim 1 , wherein the optionally substituted triarylphosphite is triphenolphosphite.
6. The method of claim 1 , wherein the optionally substituted trialkyphosphite is of general formula (IV):
wherein R 2 represents a C 1 -C 20 alkyl.
7. The method of claim 1 , wherein the optionally substituted trialkylphosphite is trimethylphosphite.
8. The method of claim 1 , wherein the optionally substituted alkanol is of general formula (V):
where R 8 and R 9 may independently be hydrogen or C 1 -C 20 alkyl, and in certain embodiments, the optionally substituted alkanol may be methanol.
9. The method of claim 1 , wherein the optionally substituted alkanol is methanol.
10. The method of claim 1 , wherein the mixture is added under a surface of the heated optionally substituted triarylphosphite.
11. The method of claim 1 , wherein the mixture is added on top of a surface of the heated optionally substituted triarylphosphite.
12. The method of claim 1 , wherein the catalyst is an alkylating catalyst.
13. The method of claim 1 , wherein the catalyst is CH 3 I.
14. The method of claim 1 , wherein the defined reaction temperature is at least greater than an exotherm created when an optionally substituted triarylphosphite is mixed at room temperature with a catalyst and an optionally substituted trialkylphosphite or an optionally substituted alkanol and further heated.
15. The method of claim 1 , further comprising maintaining the defined reaction temperature during the addition of the mixture.
16. The method of claim 1 , wherein substantially no toxic by-products are formed when the optionally substituted diaryl alkylphosphonate prepared is used in subsequent reactions.
17. A method for preparing optionally substituted diaryl alkylphosphonate comprising:
combining an optionally substituted triarylphosphite and at least one catalyst to form a triarylphosphite catalytic mixture;
heating the triarylphosphite catalytic mixture to from about 210° C. to about 260° C.;
adding to the heated triarylphosphite catalytic mixture:
(i) an optionally substituted trialkylphosphite in a molar excess of from at least 10% to about 50% of the optionally substituted triarylphosphite; or
(ii) an optionally substituted alkanol in a molar excess of from at least 10% to about 50% of the optionally substituted triarylphosphite; and
reacting the triarylphosphite catalytic mixture and the at least one optionally substituted trialkylphosphite or at least one optionally substituted alkanol to form the optionally substituted diaryl alkylphosphonate wherein the optionally substituted diaryl alkylphosphonate contains less than 1% total product residual triarylphosphite.
18. The method of claim 17 , wherein the catalyst is an alkylating catalyst.
19. The method of claim 17 , wherein the catalyst is methyl iodide.
20. The method of claim 17 , wherein the triarylphosphite catalytic mixture is stored for an indefinite period of time prior to heating.
21. The method of claim 17 , wherein the triarylphosphite catalytic mixture is substantially stable at ambient temperature.
22. The method of claim 17 , wherein the triarylphosphite catalytic mixture comprises an excess of the optionally substituted triarylphosphite compared to the catalyst.
23. The method of claim 17 , wherein the reacting step occurs at high temperature with substantially no loss of catalyst.
24. The method of claim 17 , wherein the at least one optionally substituted trialkylphosphite or the at least one optionally substitute alkanol is provided in a molar excess of from at least 10% to about 50% of the optionally substituted triarylphosphite and a catalyst.