Preparation of halohydrocarbyl phosphonic acid diesters

1. A process for producing halohydocarbyl phosphonic acid diesters of the formula (I):

in which

Z is halogen;

X and Y are hydrogen;

the halogen has an atomic weight greater than 30; and

R and R 1 are the same or different and are hydrocarbyl groups;

which process comprises reacting a trihydrocarbyl phosphite of the formula (II):

in which

R and R 1 are the same or different and have the meanings given under formula (I);

R 2 has the same meaning as R and R 1 given under formula (I) and is the same or different from either R or R 1 ;

with a hydrocarbyl halide of the formula (III):

in which

Z, X and Y have the meaning given in formula (I), and

W is a halogen having an atomic weight greater than 30;

in the presence of an effective amount of a polarity lowering additive selected from the group consisting of benzene, toluene, xylene, and alkane, the alkane selected from the group consisting of pentane, hexane, heptane, octane, and their isomers;

wherein

the molar ratio of the hydrocarbyl halide reactant to the trihydrocarbyl phosphite reactant is greater than from 2:1.

2. The process of claim 1 wherein the polarity lowering additive is selected from the group consisting of xylene, toluene, hexane, and heptane.

3. The process of claim 1 wherein

R, R 1 and R 2 are isopropyl;

the polarity lowering additive is xylene or toluene; and

the molar ratio of the halide reactant to phosphite is about 6:1.

4. The process of claim 3 wherein

Z is bromine;

W is bromine; and

R, R 1, and R 2 are isopropyl.

5. The process of claim 1 wherein the process comprises, subsequent to the reacting step, the additional step of aqueous washing the halohydrocarbyl phosphonic acid diester product to obtain a product purity level above 75% based on the trihydrocarbyl phosphite reactant; and isolating the purified product.

6. The process of claim 5 wherein the washing step comprises washing the halohydrocarbyl phosphonic acid diester product in an aqueous wash comprising water, aqueous base solutions, or aqueous acid solutions.

7. The process of claim 6 wherein the aqueous base solution is an aqueous sodium hydroxide solution or an aqueous sodium carbonate solution.

8. The process of claim 6 wherein the aqueous acid solution is an aqueous hydrochloric acid solution or an aqueous sulfuric acid solution.

9. The process of claim 5 wherein the aqueous washing is conducted at ambient temperatures or higher to increase the efficiency of the washing step.

10. The process of claim 5 wherein subsequent to the washing step, stripping is conducted on the washed product.

11. The process of claim 5 wherein prior to the washing step, the step of removing volatiles is conducted; and subsequently, the step of adding organic solvents is performed.

12. The process of claim 11 wherein the organic solvent is selected from the group consisting of heptane, hexane, toluene, and xylene.

13. The process of claim 11 wherein the washing step comprises washing the halohydrocarbyl phosphonic acid diester product in an aqueous wash comprising water, aqueous base solutions, or aqueous acid solutions.

14. The process of claim 13 wherein the aqueous base solution is an aqueous sodium hydroxide solution or an aqueous sodium carbonate solution.

15. The process of claim 13 wherein the aqueous acid solution is an aqueous hydrochloric acid solution or an aqueous sulfuric acid solution.

16. The process of claim 13 wherein the aqueous washing is conducted at ambient temperatures or higher to increase the efficiency of the washing step.

17. The process of claim 13 wherein subsequent to the washing step, stripping is conducted on the washed product.

18. The process of claim 10 wherein the polarity lowering additive and the excess halohydrocarbon recovered is recycled.

19. The process of claim 11 wherein the polarity lowering additive and the excess halocydrocarbon recovered is recycled.

20. The process of claim 17 wherein the organic solvent removed is recycled.