Process for beta-lactone production

1. A continuous method of making a beta-lactone from an epoxide, the method comprising steps of:

reacting, in a reactor, the contents of a feed stream comprising an epoxide, a solvent, a carbonylation catalyst and carbon monoxide to produce a liquid reaction product stream comprising a beta-lactone and carbonylation catalyst;

separating, outside the reactor, at least a portion of the beta-lactone in the reaction product stream from the carbonylation catalyst to produce:

i) a beta-lactone stream comprising beta-lactone, and

ii) a liquid catalyst recycling stream comprising carbonylation catalyst; and

adding the liquid catalyst recycling stream to the feed stream.

2. A continuous method of making a beta-lactone from an epoxide, the method comprising steps of:

reacting, in a reactor, the contents of a feed stream comprising an epoxide, a solvent, a carbonylation catalyst and carbon monoxide to produce a liquid reaction product stream comprising a beta-lactone and carbonylation catalyst;

returning the liquid reaction product stream to the feed stream until the weight percent of beta-lactone in the liquid reaction product stream is in the range of about 10% to about 90%; and

then separating, outside the reactor, at least a portion of the beta-lactone in the liquid reaction product stream from the carbonylation catalyst to produce:

i) a beta-lactone stream comprising beta-lactone, and

ii) a liquid catalyst recycling stream comprising carbonylation catalyst; and

adding the liquid catalyst recycling stream to the feed stream.

3. The method of claim 1 , further comprising treating the beta-lactone stream under conditions to convert the beta-lactone into a compound selected from the group consisting of acrylic acid, acrylates, acrylamide, and polyacrylates.

4. The method of claim 1 , further comprising treating the beta-lactone stream under conditions to convert the beta-lactone into a compound selected from the group consisting of acrylic acid, methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, and 2-ethylhexyl acrylate.

5. The method of claim 1 , further comprising treating the beta-lactone stream under conditions to convert the beta-lactone into acrylic acid.

6. The method of claim 1 , wherein at the same pressure the solvent has a boiling point that is higher than the boiling point of the beta-lactone.

7. The method of claim 1 , wherein the liquid catalyst recycling stream comprises beta-lactone.

8. The method of claim 1 , wherein the liquid reaction product stream comprises epoxide.

9. The method of claim 8 , wherein the liquid reaction product stream comprises an amount of epoxide sufficient to prevent anhydride formation.

10. The method of claim 8 , wherein the liquid reaction product stream comprises at least about 0.1% epoxide by weight.

11. The method of claim 1 , further comprising treating the liquid catalyst recycling stream, prior to the adding step, by adding fresh carbonylation catalyst, removing spent carbonylation catalyst, adding solvent, adding epoxide, adding beta-lactone taken from the beta-lactone stream, or a combination thereof.

12. The method of claim 1 , wherein the separating step comprises volatilizing at least a portion of the beta-lactone from the liquid reaction product stream to produce the beta-lactone stream.

13. The method of claim 1 , wherein the separating step comprises exposing the liquid reaction product stream to reduced pressure.

14. The method of claim 13 , wherein the reduced pressure is between about 5 Torr and about 500 Torr.

15. The method of claim 13 , wherein the reduced pressure is between about 10 Torr and about 100 Torr.

16. The method of claim 13 , wherein the reduced pressure is sufficient to reduce the boiling point of the beta-lactone by about 20 to about 100° C. below its boiling point at atmospheric pressure.

17. The method of claim 1 , wherein the separating step comprises exposing the liquid reaction product stream to elevated temperature.

18. The method of claim 17 , wherein the elevated temperature is greater than the boiling point of the beta-lactone but less than the boiling point of the solvent.

19. The method of claim 1 , wherein the separating step comprises exposing the liquid reaction product stream to reduced pressure and elevated temperature.

20. The method of claim 12 , further comprising a step of condensing beta-lactone from the beta-lactone stream.

21. The method of claim 1 , further comprising adding beta-lactone to the feed stream.

22. The method of claim 21 , wherein the beta-lactone added to the feed stream is taken from the beta-lactone stream.

23. The method of claim 22 , wherein the beta-lactone is added to the feed stream until the weight percent of beta-lactone in the liquid reaction product stream is in the range of about 10% to about 90%, and the method then comprises withdrawing beta-lactone from the liquid reaction product stream while maintaining the weight percent of beta-lactone in the liquid reaction product stream in the range of about 10% to about 90%.

24. The method of claim 1 , wherein the boiling point of the solvent is at least 20° C. higher than the boiling point of the beta-lactone.

25. The method of claim 1 , wherein the epoxide is ethylene oxide.

26. The method of claim 25 , wherein the solvent has a boiling point of at least 172° C. at atmospheric pressure and the beta-lactone is beta-propiolactone.

27. The method of claim 1 , wherein the carbonylation catalyst comprises a metal carbonyl compound.

28. The method of claim 27 , wherein the metal carbonyl compound has the general formula [QM y (CO) w ] x ,

where: Q is any ligand and need not be present;

M is a metal atom;

y is an integer from 1 to 6 inclusive;

w is a number that provides a metal carbonyl compound that is stable; and

x is an integer from −3 to +3 inclusive.

29. The method of claim 28 , wherein M is selected from the group consisting of Ti, Cr, Mn, Fe, Ru, Co, Rh, Ni, Pd, Cu, Zn, Al, Ga and In.

30. The method of claim 28 , wherein M is Co.

31. The method of claim 28 , wherein M is Co, y is 1, and w is 4.

32. The method of claim 28 , wherein the metal carbonyl compound comprises a carbonyl cobaltate and the carbonylation catalyst further comprises a Lewis acidic co-catalyst which comprises a metal-centered cationic Lewis acid.

33. The method of claim 32 , wherein the metal-centered cationic Lewis acid comprises an aluminum cation.

34. The method of claim 1 , wherein the liquid reaction product stream comprises carbon monoxide and epoxide and the separating step comprises:

separating the liquid reaction product stream into i) a gaseous stream comprising carbon monoxide and epoxide, and ii) a liquid stream comprising beta-lactone and carbonylation catalyst; and

separating the liquid stream into i) the beta-lactone stream comprising beta-lactone; and ii) the liquid catalyst recycling stream comprising carbonylation catalyst.

35. The method of claim 34 , wherein the solvent has a boiling point higher than the boiling point of the beta-lactone and the catalyst recycling stream further comprises solvent.

36. The method of claim 34 , further comprising the step of returning the gaseous stream comprising carbon monoxide and epoxide to the feed stream.

37. The method of claim 34 , wherein the solvent has a boiling point lower than the boiling point of the beta-lactone and the gaseous stream comprising carbon monoxide and epoxide further comprises solvent.

38. The method of claim 2 , wherein the liquid reaction product stream is returned to the feed stream until the weight percent of beta-lactone in the liquid reaction product stream is in the range of about 43% to about 53%, and the method then comprises withdrawing beta-lactone from the liquid reaction product stream while maintaining the weight percent of beta-lactone in the liquid reaction product stream in the range of about 43% to about 53%.

39. The method of claim 1 , wherein the beta-lactone stream is gaseous.

40. The method of claim 2 , wherein the beta-lactone stream is gaseous.