Direct epoxidation catalyst and process
A catalyst comprising a transition metal zeolite and a noble metal supported on a titania-containing carrier is disclosed. The supported noble metal has a mean mass diameter of from 2 to 200 μm. The catalyst is used in an epoxidation process comprising reacting an olefin, hydrogen, and oxygen. The supported noble metal is well dispersed in the reaction media.
1 . A catalyst comprising a transition metal zeolite, and a supported noble metal having a mean mass diameter of from 2 to 200 μm, wherein the supported noble metal comprises a noble metal and a titania-containing carrier.
2 . The catalyst of claim 1 wherein the supported noble metal has a mean mass diameter of from 5 to 150 μm.
3 . The catalyst of claim 1 wherein the supported noble metal has a mean mass diameter of from 10 to 100 μm.
4 . The catalyst of claim 1 wherein the supported noble metal has a mean mass diameter of from 15 to 50 μm.
5 . The catalyst of claim 1 wherein the transition metal zeolite is a titanium zeolite.
6 . The catalyst of claim 1 wherein the transition metal zeolite is TS-1.
7 . The catalyst of claim 1 wherein the noble metal is selected from the group consisting of gold, silver, platinum, palladium, iridium, ruthenium, rhenium, rhodium, osmium, and mixtures thereof.
8 . The catalyst of claim 1 wherein the noble metal is palladium, gold, or a palladium-gold mixture.
9 . The catalyst of claim 1 wherein the carrier contains at least 80 wt. % titania.
10 . The catalyst of claim 1 wherein the carrier contains at least 90 wt. % titania.
11 . An epoxidation process comprising reacting an olefin, hydrogen, and oxygen in the presence of the catalyst of claim 1 .
12 . The process of claim 11 wherein the supported noble metal has a mean mass diameter of from 10 to 100 μm.
13 . The process of claim 11 wherein the supported noble metal has a mean mass diameter of from 15 to 50 μm.
14 . The process of claim 11 wherein the transition metal zeolite has a mean mass diameter of from 15 to 50 μm.
15 . The process of claim 11 wherein the transition metal zeolite is a titanium zeolite.
16 . The process of claim 11 wherein the transition metal zeolite is TS-1.
17 . The process of claim 11 wherein the noble metal is selected from the group consisting of gold, silver, platinum, palladium, iridium, ruthenium, rhenium, rhodium, osmium, and mixtures thereof.
18 . The process of claim 11 wherein the noble metal is palladium, gold, or a palladium-gold mixture.
19 . The process of claim 11 wherein the carrier contains at least 90 wt. % titania.
20 . The process of claim 11 wherein the olefin is propylene.