Direct epoxidation process

1. A process comprising reacting an olefin, oxygen, and hydrogen in a slurry comprising a catalyst and a solvent in a reactor to produce an epoxide, wherein the reactor comprises gas bubbles in a churn-turbulent flow regime.

2. The process of claim 1 wherein the reactor is cylindrical and has a diameter of greater than 0.1 meter and a height-to-diameter ratio of greater than 3:1.

3. The process of claim 1 wherein the superficial gas velocity in the reactor is in the range of from 0.05 to 0.60 meters per second.

4. The process of claim 1 wherein the superficial gas velocity in the reactor is in the range of from 0.08 to 0.20 meters per second.

5. The process of claim 1 wherein the olefin, oxygen, and hydrogen are fed at or near the bottom of the reactor.

6. The process of claim 5 wherein the olefin, oxygen, and hydrogen are fed to the reactor via a sparger.

7. The process of claim 6 wherein the olefin, oxygen, and hydrogen are fed to the reactor at a jet velocity of less than 20 meters per second.

8. The process of claim 1 performed at a temperature in the range of from 30 to 100° C.

9. The process of claim 1 performed at a pressure in the range of from 150 to 400 psig.

10. The process of claim 1 wherein the catalyst comprises a transition metal zeolite and a noble metal.

11. The process of claim 10 wherein the transition metal zeolite is titanium silicalite-1.

12. The process of claim 10 wherein the noble metal is selected from the group consisting of palladium, platinum, gold, rhenium, silver, and mixtures thereof.

13. The process of claim 1 wherein the catalyst has a mean mass diameter in the range of from 20 to 100 μm.

14. The process of claim 1 wherein the catalyst concentration in the slurry is in the range of from 5 to 30 wt %.

15. The process of claim 1 wherein the olefin is propylene.