Granted Patent B2

US 8,124,797 · App. 12/459,065 · Granted Feb 28, 2012

Abstract

Claims (20)

1. A process for producing propylene oxide comprising:

(a.) contacting a titanium zeolite with a reaction feed comprising propylene, hydrogen peroxide, tertiary butyl alcohol, and water to produce a product stream comprising propylene, propylene oxide, propylene glycol, tertiary butyl alcohol, and water;

(b.) distilling the product stream to produce a first overhead stream comprising propylene and a first bottoms stream comprising propylene oxide, propylene glycol, tertiary butyl alcohol, and water;

(c.) distilling the first bottoms stream to produce a second overhead stream comprising propylene oxide and a second bottoms product stream comprising propylene glycol, tertiary butyl alcohol, and water; and distilling the second bottoms stream to produce a third overhead stream comprising an azeotrope of tertiary butyl alcohol and water and a third bottoms stream comprising propylene glycol and water.

2. The process of claim 1 wherein the titanium zeolite is a titanium-MWW zeolite.

3. The process of claim 1 wherein the hydrogen peroxide is formed by the in situ reaction of hydrogen and oxygen in the presence of a noble metal catalyst.

4. The process of claim 1 , further comprising recycling the third overhead stream back to step (a).

5. The process of claim 1 , further comprising distilling the third bottoms stream to produce a fourth overhead stream comprising water and a fourth bottoms stream comprising propylene glycol.

6. A process for producing propylene oxide comprising:

(a) contacting a catalyst comprising a titanium-MWW zeolite and a noble metal with a reaction feed comprising propylene, hydrogen, oxygen, tertiary butyl alcohol, and water to produce a product stream comprising propylene, propylene oxide, propylene glycol, tertiary butyl alcohol, and water;

(b) distilling the product stream to produce a first overhead stream comprising propylene and a first bottoms stream comprising propylene oxide, propylene glycol, tertiary butyl alcohol, and water;

(c) distilling the first bottoms stream to produce a second overhead stream comprising propylene oxide and a second bottoms product stream comprising propylene glycol, tertiary butyl alcohol, and water; and

(d) distilling the second bottoms stream to produce a third overhead stream comprising an azeotrope of tertiary butyl alcohol and water and a third bottoms stream comprising propylene glycol and water.

7. The process of claim 6 wherein the noble metal is palladium.

8. The process of claim 6 wherein the catalyst contains 0.01 to 10 weight percent of the noble metal and 0.001 to 5 weight percent of an additional metal selected from the group consisting of lead, bismuth, and rhenium.

9. The process of claim 6 wherein the catalyst comprises a noble metal supported on the titanium-MWW zeolite.

10. The process of claim 6 wherein the noble metal is supported on a carrier.

11. The process of claim 10 wherein the carrier is selected from the group consisting of carbon, titania, zirconia, niobia, silica, alumina, silica-alumina, tantalum oxide, molybdenum oxide, tungsten oxide, titania-silica, zirconia-silica, niobia-silica, and mixtures thereof.

12. The process of claim 6 , further comprising recycling the third overhead stream back to step (a).

13. The process of claim 6 , further comprising distilling the third bottoms stream to produce a fourth overhead stream comprising water and a fourth bottoms stream comprising propylene glycol.

Assignments (10)