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1. WO2001079146 - PROCEDE DE PRODUCTION D'ETHER

Note: Texte fondé sur des processus automatiques de reconnaissance optique de caractères. Seule la version PDF a une valeur juridique

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Claims:
1. A process for producing ether, comprising
- feeding a flow consisting essentially of C8 - C12 olefin(s) to a first reaction zone
(2; 21 - 25; 32) comprising at least one reactor,
- feeding alcohol(s) capable of reacting with the olefin(s) to said first reaction zone

(2; 21 - 25; 32),
- subjecting the olefm(s) and alcohol to an etherification reaction in the presence of an acidic catalyst,
- feeding the effluent from the first reaction zone (2; 21 - 25; 32) to a fractionation zone (7; 26; 37) operated under conditions sufficient to provide an overhead product and a bottoms product having different compositions,
- withdrawing a side-flow from the fractionation zone (7; 26; 37),
- conducting the side-flow either back to the first reaction zone (2; 21 - 25; 32) or to a second reaction zone (33),
- circulating the effluent of the first reaction zone (2; 21 - 25; 32) or the second reaction zone (33) back to the fractionation zone (7; 26; 37), and
- recovering the ether from the fractionation zone (7; 26; 37).

2. The process according to claim 1, wherein at least 85 wt-%, preferably at least 90 wt-% of the feed consists of C8 - C12 olefins.

3. The process according to claim 1 or 2, wherein the feed comprises C8 - Cjo isoolefins, preferably C8 isoolefins.

4. The process according to any of claims 1 - 3, wherein at least 20 wt-%>, preferably at least 50 wt-% and in particular at least 85 wt-% of the feed consists of a mixture of 2,4,4-trimethyl-l-pentene and 2,4,4-trimethyl-2-pentene.

5. The process according to any of the preceding claims, wherein the alcohol is a primary or secondary C\ - C6 -alcohol, preferably methanol.

6. The process according to any of the preceding claims, wherein the catalyst is an acidic ion-exchange resin.

7. The process according to any of claims 1 - 5, wherein the catalyst is based on a polyolefin backbone, to which a compound that contains reactive groups is grafted, where after a functional group is introduced into the fibrous structure.

8. The process according to any of the preceding claims, wherein
- the effluent of the first reaction zone (2; 21 - 25; 32) is fed to the fractionation zone (7; 26; 37) to a feed stage,
- the fractionation zone (7; 26; 37) is operated so as to provide a different hydrocarbon composition in each stage of the zone, and
- a side-flow is withdrawn from a stage different than the feed stage.

9. The process according to claim 8, wherein the side-flow is taken from a stage above the feed stage of the effluent of the first reaction zone (2; 21 - 25; 37).

10. The process according to any of the preceding claims, wherein fresh alcohol is fed to the first reaction zone (2; 21 - 25; 37) or to the second reaction zone (33).

11. The process according to any of the preceding claims, wherein the effluent of the first reaction zone (2; 21 - 25; 37) or second reaction zone (33) is returned to the fractionation zone (7; 26; 37) below the place from where the side-flow was withdrawn.

12. The process according to any of the preceding claims, wherein the etherified product is recovered as the bottoms product of the fractionation zone (7; 26; 37).

13. A process for etherification of olefins, comprising
- feeding a flow comprising olefinic hydrocarbon(s) to a system including at least one dimerisation zone (1; 31), at least one distillation zone (6; 36), and at least one etherification zone, said etherification zone comprising at least one reaction zone (2; 32, 33) and at least one fractionation zone (7; 37),
- contacting said flow with an acidic catalyst in the presence of an oxygenate at conditions at which at least a part of the olefin(s) dimerises,
- feeding the effluent from said dimerisation zone (1; 31) to said distillation zone (6; 36) where the dimerised reaction product is separated from said effluent, - circulating a flow comprising oxygenate from the distillation zone (6; 36) back to the dimerisation zone (1; 31),
- conducting at least part of the dimerised reaction product to the etherification zone (2, 7; 32 - 33, 37),
- feeding alcohol to the etherification zone (2, 7; 32 - 33, 37),
- subjecting the dimerised reaction product and alcohol to an etherification reaction in the presence of an acidic catalyst in a first reaction zone (2; 32) of the
etherification zone,
- feeding the effluent from the first reaction zone (2; 32) to a fractionation zone (7; 26; 37) operated under conditions sufficient for providing an overhead product and bottoms product having different hydrocarbon compositions,
- withdrawing a side-flow from the fractionation zone (7; 37),
- conducting the side-flow either to the first reaction zone (2; 32) or to a second reaction zone (33),
- circulating the effluent of the first reaction zone (2; 32) or the second reaction zone (33) back to the fractionation zone (7; 37), and
- recovering the ether from the fractionation zone (7; 37).

14. The process according to claim 13, wherein the olefinic hydrocarbon(s) is (are) fed to the dimerisation zone (1 ; 31) of the process.

15. The process according to claim 13 or 14, wherein the olefinic hydrocarbon(s) comprise at least 5 wt-%, preferably at least 20 wt-% isobutene.

16. The process according to any of claims 13 - 15, wherein the catalyst used in the dimerisation zone (1; 31) is an acidic ion-exchange resin.

17. The process according to any of the claims 13 - 16, wherein the oxygenate used in the dimerisation zone (1 ; 31) does not react with the olefm(s) contained in the feed.

18. The process according to claim 17, wherein the oxygenate is a tertiary alcohol having 4 -6 carbon atoms, preferably tert-butyl alcohol.

19. The process according to any of claims 13 - 18, wherein the dimerised reaction product is obtained as the bottoms product of the distillation zone (6; 36).

20. The process according to any of claims 13 - 19, wherein the at least 20 wt-% of the dimerised reaction product consists essentially of 2,4,4-trimethyl-l-pentene and 2,4,4-trimethyl-2-pentene.

21. The process according to any of claims 13 - 20, wherein 5 - 100 wt-%, preferably 10 - 80 wt-%), and in particular 20 - 75 wt-% of the dimerised reaction product is conducted to the etherification zone.

22. The use of the dimerised reaction product obtained from a process which comprises the steps of
- feeding a flow comprising olefinic hydrocarbon(s) to a system including at least one dimerisation zone (1; 31) and at least one distillation zone (6; 36),
- contacting said flow with an acidic catalyst in the presence of an oxygenate at conditions at which at least a part of the olefm(s) dimerises,
- feeding the effluent from said dimerisation zone (1; 31) to said distillation zone (6; 36) where the dimerised reaction product is separated from said effluent,
- circulating a flow comprising oxygenate from the distillation zone (6; 36) back to the dimerisation zone (1; 31), and
- recovering the dimerised reaction product from the distillation zone,
as the olefinic feedstock in an etherification process.

23. The use according to claim 22, wherein the olefinic hydrocarbon(s) comprise at least 20 wt-% of isobutene.

24. An apparatus for producing an etherification product, comprising in combination:
- at least one dimerisation reactor (1) having an inlet nozzle for a feed of a hydrocarbon feedstock and an outlet nozzle for withdrawal of a dimerization product;
- at least one first distillation column (6) connected to the outlet nozzle of the dimerisation reactor (1) for fractionating the dimerisation product withdrawn from the dimerisation reactor (1) and having a bottoms outlet nozzle and an outlet nozzle for a sidedraw, said outlet nozzle of the sidedraw being connected to the inlet nozzle of the dimerization reactor (1);
- at least one etherification reactor (2) having an inlet nozzle connected to the bottoms outlet of the first distillation column (6) and further having an outlet nozzle for withdrawal of an etherification product; and
- a second distillation column (7) connected to the outlet nozzle of the etherification reactor (2) for fractionating the etherification product and having a bottoms outlet nozzle and an outlet nozzle for a sidedraw, said outlet nozzle of the sidedraw being connected to the inlet nozzle of the etherification reactor (2).