Isothermal process for phosphoromonochloridite synthesis
View Patent ↗The present invention relates to a process for preparation of a phosphoromonochloridite in high yield by contacting phosphorus trichloride (PCl 3 ) with an aromatic diol in a solution of one or more organic solvents under reaction conditions sufficient to produce the phosphoromonochloridite. The reaction is carried out by adding a feed solution containing the aromatic diol dissolved in a first organic solvent into a reaction zone containing PCl 3 , and optionally one or more second organic solvents, the addition being conducted so as to maintain substantially isothermal process conditions. The reaction solution comprises greater than 0.01 to less than 5 mole percent of a nitrogen base.
1. A process for preparing a phosphoromonochloridite
comprising,
contacting an aromatic diol represented by the following formula:
wherein:
m is zero, 1, or 2;
R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7 and R 8 are each independently selected from hydrogen, halogen, and C 1 -C 10 substituted or unsubstituted hydrocarbyl moieties;
optionally, R 2 can be bonded to R 3 to form a substituted or unsubstituted hydrocarbylene moiety so as to form a 5- or 6-membered ring; and/or
optionally, R 4 can be bonded to R 5 to form a substituted or unsubstituted hydrocarbylene moiety so as to form a 5- or 6-membered ring;
with phosphorus trichloride (PCl 3 ) in a reaction solution in a reaction zone, which solution comprises greater than about 0.01 to less than 5 mole percent of a nitrogen base, calculated on moles of aromatic diol used, at a reaction temperature sufficient to produce the phosphoromonochloridite represented by the following formula:
wherein m and R 1 through R 8 have the definitions given hereinabove, and sufficient to drive off HCl being produced from the reaction solution; wherein the contacting is carried out by adding a feed solution of the aromatic diol to the reaction zone comprising PCl 3 to form the reaction solution, the addition being at such a rate that the reaction temperature remains substantially isothermal, the feed solution comprising essentially all of the aromatic diol dissolved in a first organic solvent, and wherein the molar ratio of PCl 3 to aromatic diol dissolved in the reaction solution at any given time is greater than 10:1.
2. The process of claim 1 wherein m is zero or 1.
3. The process of claim 1 wherein R 1 , R 6 , R 7 and R 8 are each hydrogen.
4. The process of claim 1 wherein the aromatic diol is 2,2′-biphenol.
5. The process of claim 1 wherein the first organic solvent is a hydrocarbon or chlorinated hydrocarbon compound having a boiling point of greater than about 90° C. and less than about 250° C.
6. The process of claim 1 wherein the first organic solvent is a polar aprotic organic solvent having a dielectric constant greater than about 6.
7. The process of claim 1 wherein the first organic solvent is a mixture of a polar aprotic organic solvent having a dielectric constant greater than about 6 and a hydrocarbon or chlorinated hydrocarbon compound having a boiling point greater than about 90° C. and less than about 250° C.
8. The process of claim 7 wherein the polar organic solvent is tetrahydrofuran.
9. The process of claim 1 wherein the reaction zone further comprises a second organic solvent in a volume from about one time to about 15 times of the volume of PCl 3 .
10. The process of claim 9 wherein the second organic solvent is a hydrocarbon or chlorinated hydrocarbon compound having a boiling point of greater than about 90° C. and less than about 250° C.
11. The process of claim 5 wherein the hydrocarbon or chlorinated hydrocarbon compound is selected from the group consisting of toluene, chlorobenzene, o-xylene, m-xylene, p-xylene, ethylbenzene, heptane, octane, and mixtures thereof.
12. The process of claim 1 wherein the feed solution comprises from greater than about 5 percent to less than about 50 percent of the aromatic diol by weight, based on the weight of the feed solution.
13. The process of claim 1 wherein the molar ratio of the PCl 3 to total moles of aromatic diol employed is greater than about 1.0 to less than 3.5.
14. The process of claim 1 wherein the contacting is conducted at a reaction temperature greater than about 40° to below about 115° C.
15. The process of claim 14 wherein the feed solution is added into the reaction zone in a time greater than about 3 hours to less than about 60 hours.
16. The process of claim 1 wherein the process further comprises removing unreacted PCl 3 to obtain a solution of the phosphoromonochloridite.
17. A process of preparing 1,1′-biphenyl-2,2′-diyl phosphoromonochloridite, the process comprising, contacting 2,2′-biphenol with PCl 3 in a reaction solution in a reaction zone, which reaction solution comprises greater than about 0.01 and less than 5 mole percent of a nitrogen base, calculated on moles of the 2,2′-biphenol, at a temperature sufficient to produce 1,1′-biphenyl-2,2′-diyl phosphoromonochloridite and sufficient to reflux the reaction solution to drive off hydrogen chloride produced as a co-product; wherein the contacting is carried out by adding a feed solution comprising the 2,2′-biphenol essentially all dissolved in a mixture of tetrahydrofuran and toluene into the reaction zone comprising PCl 3 diluted in toluene to form the reaction solution, the addition being at such a rate that the reaction temperature remains substantially isothermal.
18. The process of claim 17 wherein the molar ratio of PCl 3 to total 2,2′-biphenol employed is greater than about 1.0 to less than 3.5.
19. The process of claim 17 wherein the reaction temperature is about 98° C.±5° C. and the addition of the feed solution takes from more than about 3 hours to less than about 60 hours.
20. The process of claim 17 wherein the weight ratio of tetrahydrofuran to toluene is greater than about 1/10 and less than about 10/1.