Selective hydrogenation catalyst and methods of making and using same

1. A method of producing a selective hydrogenation catalyst comprising:

contacting an inorganic catalyst support with a chlorine-containing compound to form a chlorided catalyst support;

subsequently removing at least some of the chlorine-containing compound from the chlorided catalyst support to form a clean chlorided catalyst support; and

subsequently adding palladium to the clean chlorided catalyst support to form a supported-palladium composition.

2. The method of claim 1 , wherein the chlorine-containing compound comprises hydrochloric acid, an alkaline metal chloride, an alkaline earth chloride, chlorohydrocarbons, or combinations thereof.

3. The method of claim 1 , wherein the chlorine-containing compound comprises a compound described by the formula N(H v R w R′ x R″ y R′″ z )Cl; where R, R′, R″, and R′″ is methyl, ethyl, propyl, butyl, or any combination thereof; and each of v, w, x, y, z can be 0 to 4 provided that v+w+x+y+z=4.

4. The method of claim 1 , wherein the chlorine-containing compound comprises a compound described by the formula CCl x H y , wherein x+y=4.

5. The method of claim 1 , wherein the chlorine-containing compound comprises a compound described by the formula C 2 Cl x H y , wherein x+y=6.

6. The method of claim 1 , wherein the chlorine containing compound comprises potassium chloride, sodium chloride, lithium chloride, calcium chloride, barium chloride, ammonium chloride, methyl ammonium chloride, tetramethylanmonium chloride, tetraethylammonium chloride, carbon tetrachloride, trichloroethane, or combinations thereof.

7. The method of claim 1 , wherein the clean chlorided catalyst support has from about 5 to about 2000 ppm by weight chlorine.

8. The method of claim 1 , wherein the selective hydrogenation catalyst comprises from about 0.01 to about 1.0 weight percent palladium based on a total weight of the catalyst.

9. The method of claim 1 , further comprising drying the supported-palladium composition, calcining the supported-palladium composition, or both.

10. The method of claim 1 , further comprising adding at least one selectivity enhancer to the supported-palladium composition to form an enhanced supported-palladium composition, wherein the selectivity enhancer comprises a compound selected from the group consisting of Group 1B metals, Group 1B metal compounds, phosphorus, sulfur, phosphorus-containing compounds, sulfur-containing compounds, alkaline metals, alkaline metal-containing compounds, silver, silver-containing compounds, iodine, iodide-containing compounds, and combinations thereof.

11. The method of claim 10 , wherein the enhanced supported-palladium composition comprises from about 0.001 to about 10 weight percent selectivity enhancer based on a total weight of the catalyst.

12. The method of claim 10 , further comprising drying the enhanced supported-palladium composition, calcining the enhanced supported-palladium composition, or both.

13. The method of claim 1 , further comprising reducing the supported-palladium composition.

14. The method of claim 10 wherein the chlorided catalyst support contains from about 5 to about 2000 ppm by weight of chlorine, wherein the supported-palladium composition comprises from about 0.01 to about 1.0 weight percent palladium based on a total weight of the supported-palladium composition, and wherein the enhanced supported-palladium composition comprises from about 0.01 to about 10 weight percent silver based on a total weight of the enhanced supported-palladium composition.

15. The method of claim 14 , wherein the chlorided catalyst support comprises from about 10 to about 1200 ppm by weight of chlorine, wherein the supported-palladium composition comprises from about 0.01 to about 0.8 weight percent palladium based on a total weight of the supported-palladium composition, and wherein the enhanced supported-palladium composition comprises from about 0.01 to about 5 weight percent silver based on a total weight of the enhanced supported-palladium composition.

16. The method of claim 14 , wherein the enhanced supported-palladium composition further comprises one or more selectivity enhancers selected from the group consisting of iodine, iodide-containing compounds, phosphorus, phosphorus-containing compounds, sulfur, sulfur-containing compounds, alkaline metals, alkaline metal-containing compounds, and combinations thereof.

17. The method of claim 16 , wherein the enhanced supported-palladium composition comprises from about 0.001 to about 10 weight percent selectivity enhancer based on a total weight of the enhanced supported-palladium composition.

18. The method of claim 1 , wherein the inorganic catalyst support is contacted with the chlorine-containing compound using incipient wetness impregnation.

19. The method of claim 1 , wherein the supported-palladium composition comprises a palladium skin comprising at least about 95 percent of the palladium in the composition.

20. The method of claim 1 , wherein the chlorided catalyst support comprises from about 0.001 weight percent to about 2 weight percent chlorine, and wherein the clean chlorided catalyst support comprises from about 30 ppm to about 400 ppm chlorine.

21. A method of producing a selective hydrogenation catalyst comprising:

contacting an inorganic catalyst support with a chlorine-containing compound;

subsequently washing the catalyst support; and

subsequently adding palladium to the catalyst support.

22. The method of claim 21 further comprising drying the inorganic catalyst support subsequent to the contacting and prior to the washing.

23. The method of claim 22 further comprising calcining the inorganic catalyst support subsequent to the drying and prior to the washing.

24. The method of claim 23 further comprising drying the inorganic catalyst support subsequent to the washing and prior to the adding.

25. The method of claim 21 further comprising adding a selectivity enhancer to the inorganic catalyst support.