Process for making diaryl sulfones
A process for preparing diaryl sulfones, such as 4,4′-dichlorodiphenylsulfone is disclosed. The process comprises contacting an aryl compound with sulfur trioxide to provide a benzene sulfonic acid. The benzene sulfonic acid is coupled to additional aryl compound in the presence of a catalyst. During the coupling step, the additional aryl compound is continuously added while water is removed.
1. A process for preparing a sulfone of the formula
wherein X 1 and X 2 are independently H, halogen, C 1 -C 6 alkyl, C 6 -C 10 aryl, —C 1 -C 6 alkyl-(C 6 -C 10 aryl), —C 1 -C 6 alkyl or —C 6 -C 10 aryl, wherein each hydrogen atom in C 1 -C 6 alkyl, C 6 -C 10 aryl, —C 1 -C 6 alkyl-(C 6 -C 10 aryl), —C 1 -C 6 alkyl or —C 6 -C 10 aryl is independently optionally substituted with a halogen, C 1 -C 6 alkyl, C 6 -C 10 aryl, —C 1 -C 6 alkyl-(C 6 -C 10 aryl), —C 1 -C 6 alkyl or —C 6 -C 10 aryl; the process comprising
a. a coupling step comprising contacting a sulfonic acid of the formula
with an aryl compound of the formula
in the presence of a catalyst selected from the group consisting of aluminum oxide, antimony oxide, zirconium oxide, bismuth oxide, ferric oxide, stannic oxide, titanium oxide, titanium sulfate, zinc oxide, iodine, lithium iodide, and silica, wherein resulting water is removed during the coupling step; and
wherein trifluoroacetic anhydride is not present in the coupling step, and
wherein the process is free of dimethyl sulfate.
2. The process of claim 1 , wherein X 1 and X 2 are Cl.
3. The process of claim 1 , wherein the crude yield of the coupling step, as determined by the sulfone relative to the sulfonic acid, is about 60% to about 95%.
4. The process of claim 1 , wherein the purified yield of the coupling step, as determined by the sulfone relative to the sulfonic acid, is about 50% to about 85%.
5. The process of claim 1 , wherein the coupling step is initiated under anhydrous conditions.
6. The process of claim 1 , wherein the coupling step is initiated with less than about 10 wt % water.
7. The process of claim 1 , wherein the resulting water is removed continuously during the coupling step.
8. The process of claim 1 , wherein the resulting water is removed by distillation.
9. The process of claim 1 , wherein the concentration of water throughout the coupling step is less than about 10 wt % water.
10. The process of claim 1 , wherein the coupling step is performed without a dehydrating reagent.
11. The process of claim 1 , wherein the concentration of the catalyst relative to all components of the coupling step, when the coupling step is initiated, is about 0.7 wt % to about 1.1 wt %.
12. A process for preparing a sulfone of the formula
wherein X 1 and X 2 are independently H, halogen, C 1 -C 6 alkyl, C 6 -C 10 aryl, —C 1 -C 6 alkyl-(C 6 -C 10 aryl), —C 1 -C 6 alkyl or —C 6 -C 10 aryl, wherein each hydrogen atom in C 1 -C 6 alkyl, C 6 -C 10 aryl, —C 1 -C 6 alkyl-(C 6 -C 10 aryl), —C 1 -C 6 alkyl or —C 6 -C 10 aryl is independently optionally substituted with a halogen, C 1 -C 6 alkyl, C 6 -C 10 aryl, —C 1 -C 6 alkyl-(C 6 -C 10 aryl), —C 1 -C 6 alkyl or —C 6 -C 10 aryl; the process comprising
a. a coupling step comprising contacting a sulfonic acid of the formula
with an aryl compound of the formula
in the presence of a catalyst selected from the group consisting of aluminum oxide, antimony oxide, zirconium oxide, bismuth oxide, ferric oxide, stannic oxide, titanium oxide, titanium sulfate, zinc oxide, iodine, lithium iodide, and silica, wherein resulting water is removed during the coupling step,
wherein the concentration of the catalyst relative to the sulfonic acid, when the coupling step is initiated, is about 0.01 equivalent to about 0.1 equivalent,
wherein the process is free of dimethyl sulfate.
13. The process of claim 1 , wherein the coupling step results in less than 20% of a 2,4′ isomer of the formula
wherein X 1 and X 2 are independently H, halogen, C 1 -C 6 alkyl, C 6 -C 10 aryl, —C 1 -C 6 alkyl-(C 6 -C 10 aryl), —C 1 -C 6 alkyl or —C 6 -C 10 aryl, wherein each hydrogen atom in C 1 -C 6 alkyl, C 6 -C 10 aryl, —C 1 -C 6 alkyl-(C 6 -C 10 aryl), —C 1 -C 6 alkyl or —C 6 -C 10 aryl is independently optionally substituted with a halogen, C 1 -C 6 alkyl, C 6 -C 10 aryl, —C 1 -C 6 alkyl-(C 6 -C 10 aryl), —C 1 -C 6 alkyl or —C 6 -C 10 aryl, as determined by the 2,4′ isomer relative to all sulfone products.
14. The process of claim 1 , wherein the coupling step results in less than 20% of a 3,4′ isomer of the formula
wherein X 1 and X 2 are independently H, halogen, C 1 -C 6 alkyl, C 6 -C 10 aryl, —C 1 -C 6 alkyl-(C 6 -C 10 aryl), —C 1 -C 6 alkyl or —C 6 -C 10 aryl, wherein each hydrogen atom in C 1 -C 6 alkyl, C 6 -C 10 aryl, —C 1 -C 6 alkyl-(C 6 -C 10 aryl), —C 1 -C 6 alkyl or —C 6 -C 10 aryl is independently optionally substituted with a halogen, C 1 -C 6 alkyl, C 6 -C 10 aryl, —C 1 -C 6 alkyl-(C 6 -C 10 aryl), —C 1 -C 6 alkyl or —C 6 -C 10 aryl, as determined by the 3,4′ isomer relative to all sulfone products.
15. The process of claim 1 , wherein the aryl compound is added to the sulfonic acid continuously at the same time that water is removed continuously from the sulfonic acid.
16. The process of claim 1 , wherein the aryl compound is added to the sulfonic acid continuously at the same time that wet chlorobenzene is removed continuously from the sulfonic acid.
17. The process of claim 1 , wherein the aryl compound is added at a flow rate of about 1.5 mL/min.
18. The process of claim 1 , wherein the coupling step is performed at a pressure of about 30 psi to about 60 psi.
19. The process of claim 1 , further comprising removing the aryl compound from the sulfone by distillation after the coupling step.
20. The process of claim 1 , further comprising extracting the sulfone after the coupling step.
21. The process of claim 1 , further comprising washing the sulfone with water.
22. The process of any claim 21 , wherein the washing step results in the sulfone being substantial free of the sulfonic acid.
23. The process of claim 1 , further comprising crystallizing the sulfone.
24. The process of claim 23 , wherein the crystallizing step results in the sulfone having a purity of greater than about 99%.
25. The process of claim 1 , further comprising a first step comprising contacting a reactant of the formula
wherein X 1 is a H, halogen, C 1 -C 6 alkyl, C 6 -C 10 aryl, —C 1 -C 6 alkyl-(C 6 -C 10 aryl), —C 1 -C 6 alkyl or —C 6 -C 10 aryl, wherein each hydrogen atom in C 1 -C 6 alkyl, C 6 -C 10 aryl, —C 1 -C 6 alkyl-(C 6 -C 10 aryl), —C 1 -C 6 alkyl or —C 6 -C 10 aryl is independently optionally substituted with a halogen, C 1 -C 6 alkyl, C 6 -C 10 aryl, —C 1 -C 6 alkyl-(C 6 -C 10 aryl), —C 1 -C 6 alkyl or —C 6 -C 10 aryl, with sulfur trioxide to provide a first product mixture comprising the sulfonic acid.
26. The process of claim 25 , wherein X 1 is Cl.