Oligomerization of hydrocarbons

1. A process comprising:

(1) separating a hydrocarbon stream in a separation zone to provide a separated product comprising olefins;

(2) contacting said olefins with at least one guard bed to provide pretreated olefins, wherein said guard beds contain a compound selected from the group consisting of a 3 Angstrom molecular sieve, silica gel and a 13X sieve,

(3) contacting said pretreated olefins with a catalyst comprising a zeolite in an oligomerization zone under oligomerization reaction conditions to form an oligomerization product; and

(4) recovering said oligomerization product;

wherein the reid vapor pressure of the hydrocarbon stream is higher than the reid vapor pressure of the oligomerization product and a feed comprising 10 wt% 1-butene and 1 wt% isobutene in isopentane would have greater than 99% conversion at 55 hours with a selectivity to C 8 of 35.91 wt%

wherein said zeolite is treated with a compound comprising a metal selected from the group consisting of tin prior to said contacting with said olefins in step (3).

2. A process in accordance with claim 1 wherein said zeolite has a molar ratio of SiO 2 to Al 2 O 3 in its crystalline framework in the range of from about 10:1 to about 150:1.

3. A process in accordance with claim 1 wherein said zeolite has a molar ratio of SiO 2 to Al 2 O 3 in its crystalline framework in the range of from about 30:1 to about 100:1.

4. A process in accordance with claim 1 wherein said zeolite is a mordenite.

5. A process in accordance with claim 1 wherein said zeolite is mordenites having a silica to alumina molar ratio of 40:1.

6. A process in accordance with claim 1 wherein said zeolite is mordenites having a silica to alumina molar ratio of 90:1.

7. A process in accordance with claim 1 wherein said zeolite is promoted with hydrogen.

8. A process in accordance with claim 1 wherein said olefins have in the range of from 2 to 20 carbon atoms per molecule.

9. A process in accordance with claim 1 wherein said olefins have in the range of from 3 to 6 carbon atoms per molecule.

10. A process in accordance with claim 1 wherein said olefins have in the range of from 4 to 5 carbon atoms per molecule.

11. A process in accordance with claim 1 wherein said olefins have 4 carbon atoms per molecule.

12. A process in accordance with claim 1 wherein said olefins have 5 carbon atoms per molecule.

13. A process in accordance with claim 1 wherein said oligomerization reaction conditions include a temperature in the range of from about 35° C. to about 260° C.

14. A process in accordance with claim 1 wherein said oligomerization reaction conditions include a temperature in the range of from about 65° C. to about 150° C.

15. A process in accordance with claim 1 wherein said oligomerization reaction conditions include a temperature in the range of from 90° C. to 130° C.

16. A process in accordance with claim 1 wherein said olefins are contacted with one to four separate guard beds in step (2).

17. A process in accordance with claim 1 wherein said at least one guard bed is regenerated by a process comprising the steps of: (a) contacting a regeneration stream with said guard bed to form an adsorbed stream; (b) condensing said adsorbed stream to form a condensed stream; (c) adding water to said condensed stream to form a waste stream; and (d) disposing of said waste stream.

18. A process in accordance with claim 17 wherein said regeneration stream is air.

19. A process in accordance with claim 17 wherein said regeneration stream is a gaseous organic compound.

20. A process in accordance with claim 19 wherein said gaseous organic compound is gaseous isobutane.

21. A process in accordance with claim 1 , further comprising regenerating said catalyst in a regeneration zone under regeneration conditions.

22. A process in accordance with claim 21 wherein said regeneration conditions comprise contacting said catalyst with a regeneration stream selected from the group consisting of nitrogen, air, supercritical isobutane, and light hydrocarbons.

23. A process in accordance with claim 21 wherein said regeneration conditions further comprise a temperature in the range of from about 50° C. to about 900° C.

24. A process in accordance with claim 1 , further comprising: (4) separating compounds comprising n-alkenes from said oligomerization product; (5) contacting said compounds comprising n-alkenes with an isomerization catalyst in an isomerization reaction zone under isomerization conditions to form an isomerization product; and (6) returning said isomerization product to said oligomerization zone.