METHOD FOR THE HYDROFORMYLATION OF OLEFINS

Abstract

Process for hydroformylation of olefins having 6 to 20 carbon atoms in the presence of a cobalt catalyst in the presence of an aqueous phase with thorough mixing in a reactor wherein a hydroformylation products-containing first stream is withdrawn at the top of the reactor and an aqueous phase-containing second stream is withdrawn from the bottom of the reactor via at least one line leading out of the bottom of the reactor, which process comprises controlling one or more mass flow parameters of the second stream in accordance with the density of the second stream.

Claims

1-15. (canceled)

16. A process for hydroformylation of olefins having 6 to 20 carbon atoms in the presence of a cobalt catalyst in the presence of an aqueous phase with thorough mixing in a reactor wherein a hydroformylation products-containing first stream is withdrawn at the top of the reactor and an aqueous phase-containing second stream is withdrawn from the bottom of the reactor via at least one line leading out of the bottom of the reactor, which process comprises controlling one or more mass flow parameters of the second stream in accordance with the density of the second stream.

17. The process according to claim 16, wherein the density of the second stream is measured in the line leading out of the bottom of the reactor.

18. The process according to claim 16, wherein one or more mass flow parameters are the mass flow, the mass flow rate or any other parameter determined on the basis of the mass flow and/or the mass flow rate.

19. The process according to claim 16, comprising measuring the density of the second stream to determine one or more controlled variables on basis of the measured density, comparing the one or more controlled variables with one or more reference values to determine one or more controlling quantities and using the one or more controlling quantities to determine one or more actuating signals to control the one or more mass flow parameters of the second stream.

20. The process according to claim 16, wherein the density is measured by one or more Coriolis mass flow meters.

21. The process according to claim 16, wherein the measured density of the second stream is compared with a predefined reference value for the density of the second stream and the mass flow and/or the mass flow rate of the second is increased if the measured density of the second stream is above the predefined reference value for the density of the second stream.

22. The process according to claim 16, wherein the measured density of the second stream is compared with a predefined reference value for the density of the second stream and the mass flow and/or the mass flow rate of the second stream is decreased if the measured density of the second stream is below the predefined reference value for the density of the second stream.

23. The process according to claim 16, wherein the density of the second stream is measured at at least one point in the line leading out of the bottom of the reactor.

24. The process according to claim 16, wherein the first stream and the second stream are passed into a post-reactor.

25. The process according to claim 24, wherein a hydroformylation products containing first stream is withdrawn at the top of the post-reactor and an aqueous phase-containing second stream is withdrawn from the bottom of the post-reactor.

26. The process according to claim 25, wherein the one or more mass flow parameters of the second stream withdrawn from the bottom of the post-reactor via at least one line leading out of the bottom of the post-reactor is controlled in accordance with the density of the second stream.

27. The process according to claim 16, wherein the first stream and second stream, withdrawn from the reactor or in case a post-reactor is in place withdrawn from the post-reactor, are subjected in the presence of aqueous cobalt(II) salt solution to oxygen treatment wherein the cobalt catalyst decomposes to form cobalt(II) salts which are extracted into the aqueous phase and the phases are then separated.

28. The process according to claim 27, wherein the water content in the reactor, in case a post-reactor is used in the post-reactor and in the phase separation is controlled by means of dynamic decoupling.

29. The process according to claim 16, wherein the temperature in the reactor is from 100 to 250° C. and in case a post-reactor is used, the temperature in the post-reactor is from 100 to 250° C.

30. The process according to claim 16, wherein the prevailing pressure in the reactor is from 100 to 400 bar abs and in case a post-reactor is used, the prevailing pressure in the post-reactor is from 100 to 400 bar abs.

Description

[0073] FIG. 1 Preferred embodiments of the invention are the following. These embodiments do not limit the scope of the invention.

[0074] 1. Process for hydroformylation of olefins having 6 to 20 carbon atoms in the presence of a cobalt catalyst in the presence of an aqueous phase with thorough mixing in a reactor wherein a hydroformylation products-containing first stream is withdrawn at the top of the reactor and an aqueous phase-containing second stream is withdrawn from the bottom of the reactor via at least one line leading out of the bottom of the reactor, which process comprises controlling one or more mass flow parameters of the second stream in accordance with the density of the second stream, which is preferably measured in the line leading out of the bottom of the reactor.

[0075] 2. Process according to embodiment 1, wherein the process is continuous or semi-continuous.

[0076] 3. Process according to embodiment 1 or 2, wherein one or more mass flow parameters are the mass flow, the mass flow rate or any other parameter determined on the basis of the mass flow and/or the mass flow rate.

[0077] 4. Process according to any one of the embodiments 1 to 3, comprising measuring the density of the second stream to determine one or more controlled variables on basis of the measured density, comparing the one or more controlled variables with one or more reference values to determine one or more controlling quantities and using the one or more controlling quantities to determine one or more actuating signals to control the one or more mass flow parameters of the second stream, preferably by means of a closed loop control system.

[0078] 5. Process according to any one of the embodiments 1 to 4, wherein the density is measured by one or more Coriolis mass flow meters.

[0079] 6. Process according to any one of the embodiments 1 to 5, wherein the measured density of the second stream is compared with a predefined reference value for the density of the second stream and the mass flow and/or the mass flow rate of the second is increased if the measured density of the second stream is above the predefined reference value for the density of the second stream.

[0080] 7. Process according to any one of the embodiments 1 to 6, wherein the measured density of the second stream is compared with a predefined reference value for the density of the second stream and the mass flow and/or the mass flow rate of the second stream is decreased if the measured density of the second stream is below the predefined reference value for the density of the second stream.

[0081] 8. Process according to any one of the embodiments 1 to 7, wherein the density of the second stream is measured at at least one point in the line leading out of the bottom of the reactor.

[0082] 9. Process according to one any of the embodiments 1 to 8, wherein the thorough mixing is carried out by means of a mixing nozzle.

[0083] 10. Process according to any one of the embodiments 1 to 9, wherein the first stream and the second stream are passed into a post-reactor.

[0084] 11. Process according to embodiment 10, wherein a hydroformylation products containing first stream is withdrawn at the top of the post-reactor and an aqueous phase-containing second stream is withdrawn from the bottom of the post-reactor.

[0085] 12. Process according to embodiment 11, wherein the one or more mass flow parameters of the second stream withdrawn from the bottom of the post-reactor via at least one line leading out of the bottom of the post-reactor is controlled in accordance with the density of the second stream, which is preferably measured in the line leading out of the bottom of the post-reactor.

[0086] 13. Process according to embodiment 12, wherein one or more mass flow parameters are the mass flow, the mass flow rate or any other parameter determined on the basis of the mass flow and/or the mass flow rate.

[0087] 14. Process according to any one of the embodiments 12 to 13, comprising measuring the density of the second stream to determine one or more controlled variables on basis of the measured density, comparing the one or more controlled variables with one or more reference values to determine one or more controlling quantities and using the one or more controlling quantities to determine one or more actuating signals to control the one or more mass flow parameters of the second stream, preferably by means of a closed loop control system.

[0088] 15. Process according to any one of the embodiments 12 to 14, wherein the density is measured by one or more Coriolis mass flow meters.

[0089] 16. Process according to any one of the embodiments 12 to 15, wherein the measured density of the second stream is compared with a predefined reference value for the density of the second stream and the mass flow and/or the mass flow rate of the second is increased if the measured density of the second stream is above the predefined reference value for the density of the second stream.

[0090] 17. Process according to any one of the embodiments 12 to 16, wherein the measured density of the second stream is compared with a predefined reference value for the density of the second stream and the mass flow and/or the mass flow rate of the second stream is decreased if the measured density of the second stream is below the predefined reference value for the density of the second stream.

[0091] 18. Process according to any one of the embodiments 12 to 17, wherein the density of the second stream is measured at at least one point in the line leading out of the bottom of the reactor.

[0092] 19. Process according to any one of the embodiments 1 to 18, comprising a catalyst formation step wherein an aqueous cobalt(ll) salt solution is brought into intimate contact with carbon monoxide and hydrogen to form the cobalt catalyst.

[0093] 20. Process according to any one of the embodiments 1 to 19, wherein the formation of the cobalt catalyst, the extraction of the cobalt catalyst into the organic phase and the hydroformylation of the olefins are carried out in association with one another in the same reactor by bringing the aqueous cobalt(ll) salt solution, carbon monoxide, hydrogen and olefins and, optionally, an organic solvent into intimate contact with one another in the reactor under hydroformylation conditions.

[0094] 21. Process according to any one of the embodiments 1 to 20, wherein the first stream and second stream, withdrawn from the reactor or in case a post-reactor is in place withdrawn from the post-reactor, are subjected in the presence of aqueous cobalt(II) salt solution to oxygen treatment wherein the cobalt catalyst decomposes to form cobalt(II) salts which are extracted into the aqueous phase and the phases are then separated.

[0095] 22. Process according to any one of the embodiments 1 to 21, wherein part of the aqueous phase is recycled into the reactor or into the catalyst formation step.

[0096] 23. Process according to any one of the embodiments 21 to 22, wherein the mass flow and/or the mass flow rate of the aqueous phase withdrawn from the phase separation is controlled in accordance with the one or more mass flow parameters of the second stream withdrawn from the reactor, and if a post-reactor is used, also in accordance with the one or more mass flow parameters of the second stream withdrawn from the post-reactor.

[0097] 24. Process according to embodiment 23, wherein control of the mass flow and/or mass flow rate of the aqueous phase withdrawn from the phase separation in accordance with the one or more mass flow parameters of the second stream withdrawn from the reactor, and if a post-reactor is used, also in accordance with the one or more mass flow parameters of the second stream withdrawn from the post-reactor, is achieved by dynamic decoupling of the different water inventories of the reactors and the phase separation.

[0098] 25. Process according to any of the embodiments 1 to 24 wherein a distributed control system, preferably with PID controllers is used to control the one or mass flow parameters of the second stream withdrawn from the reactor and if a post-reactor is used, also to control the one or more mass flow parameters of the second stream withdrawn from the post-reactor.

[0099] 26. Process according to embodiment 25, wherein a distributed control system, preferably with PID controllers is also used to control the mass flow and/or the mass flow rate of the aqueous phase withdrawn from the phase separation.

[0100] 27. Process according to embodiment 26, wherein one set of controllers is tuned to act slow in comparison to the other controllers.

[0101] 28. Process according to any one of the embodiments 21 to 22, wherein the water content in the reactor, in case a post-reactor is used in the post-reactor and in the phase separation is controlled by means of dynamic decoupling.

[0102] 29. Process according to any one of the embodiments 1 to 28 wherein, the temperature in the reactor is from 100 to 250° C., in particular from 145 to 200° C.

[0103] 30. Process according to any of the embodiments 1 to 29 wherein the temperature in the post-reactor is from 100 to 250° C., in particular from 145 to 200° C.

[0104] 31. Process according to any one of the embodiments 1 to 29 wherein the prevailing pressure in the reactor is from 100 to 400 bar abs, in particular from 200 to 300 bar abs.

[0105] 32. Process according to any of the embodiments 10 to 30, wherein the prevailing pressure in the post-reactor is from 100 to 400 bar abs, in particular from 200 to 300 bar abs.

EXAMPLES

[0106] The examples do not limit the invention.

Example 1

[0107] The following parameters were set in a continuous process carried out in a plant according to FIG. 1.

TABLE-US-00001 oxogas (CO:H.sub.2 = 40:60) (4) 3 300 kg/h isooctene (5) 10 000 kg/h aqueous cobalt(II) formate solution (6), ca. 1.2 % by weight of cobalt 1 100 kg/h reaction temperature in the reactor (1) 187° C. set-point of the density controller 7 0.998 g/cm.sup.3 differential pressure in line (10) set by means of pressure regulator (controlled valve) (11) 4 bar reaction temperature in the post-reactor (13) 187° C. set-point of the density controller 14 0.998 g/cm.sup.3 pressure of the phase-separator (26) set by means of pressure regulating control valve (18) 19 bar aqueous cobalt(ll) salt solution (6) 9 000 kg/h air (23) 50 kg/h offgas (29) 500 kg/h

[0108] The yield of crude hydroformylation product (28) was 12 400 kg/h.

Example 2

[0109] A laboratory miniplant system was used for continuous hydroformylation of octene. The olefin was fed to a first stirred reactor using a high-pressure pump. The synthesis gas was taken from a high-pressure pipeline. The reactor was operated at a pressure of around 300 bar.

[0110] As catalyst precursor, an aqueous solution containing 1.8 wt.-% of cobalt formiate was fed to the reactor by a high-pressure pump. (Under those conditions, the carbon monoxide present in the reactor acts as ligand for the catalyst, the catalyst forms in-situ in the reactor and moves from the water phase to the organic phase.)

[0111] The reactor discharge is fed to a lower pressure vessel and air is added to oxidise and inactivate the catalyst and to remove it from the organic phase to the water phase. The discharge of that oxidation vessel is fed to a phase separator. The feed flow to the phase separator was 431-451 g/h. Thereof, approximately 50 g/h was water fed with the catalyst solution to the reactor. The phase separator was neither heated nor thermally insulated, consequently its contents were of uniform temperature. In the phase separator, the water phase settled to the bottom and was discharged. In this miniplant, the water phase was discarded and not recycled to the reactor.

[0112] A Coriolis mass flow meter measuring and reporting mass flow, temperature and density of the discharged stream was installed in the pipe used to discharge the water from the phase separator. The density measurement was used as process variable input to a density controller, which manipulated a valve installed in the pipe used to discharge the water phase. The density set point of the controller was chosen such that the density of the discharged stream at the given temperature of 40-50° C. is in the two-phase region. This effectively ensured that all water phase was discharged from the phase separator and no liquid level measurement was needed.

[0113] Analyses were recorded daily. The amounts of organic and aqueous phases were determined by collecting the stream discharged at the bottom of the phase separator and measuring the volume of the individual phases after a settling period long enough to obtain two well separate and clear phases. Table 1 shows the results of this experiment. FIGS. 2, 3 and 4 show measured density and density set point, the share of the organic phase in the discharged mixture and the temperature of the discharged mixture, respectively, from Table 1.

[0114] This example shows that the density-controlled discharge of the aqueous phase allows to withdraw a mixture of a desired ratio of the two phases and thereby remove the aqueous phase completely without removing an undesirably high amount of organic phase, even where no temperature difference between a relatively hot reaction zone and a relatively cool aqueous phase settling zone can be determined. Since the density of the cobalt salt solution is above 1 kg/dm.sup.3, there is enough room for higher density set points, and analyses can be made continuously in a commercial plant, allowing faster control feedback, the amount of organic phase withdrawn from a commercial reactor can be even lower compared to the miniplant.

TABLE-US-00002 Day Temperature [°C] Density [kg/dm.sup.3] Density Set Point [kg/dm.sup.3] Aqueous phase [ml/h] Organic phase [ml/h] Share of organic phase [ml/ml] 1 43 0.9935 0.994 47 9 0.16 2 44 0.992 0.994 56 7 0.11 3 45 0.994 0.994 54 9 0.14 4 44 0.994 0.994 55 11 0.17 5 45 0.993 0.994 52 10 0.16 6 45 0.994 0.994 53 10 0.16 7 43 0.994 0.994 53 13 0.20 8 44 0.994 0.994 53 10 0.16 9 44 0.997 0.994 52 9 0.15 10 45 0.998 0.998 52 8 0.13 11 45 0.994 0.998 54 9 0.14 12 45 0.995 0.998 54 7 0.11 13 46 0.998 0.998 53 7 0.11 14 46 0.999 0.998 54 7 0.11 15 46 0.997 0.998 52 8 0.13 16 47 0.998 0.998 54 7 0.11 17 44 0.999 0.998 55 6 0.10 18 44 0.998 0.998 54 7 0.11 19 44 0.999 0.998 54 7 0.11 20 45 0.999 0.998 54 6 0.1 21 44 0.997 0.998 53 6 0.10 22 44 0.996 0.998 54 7 0.11 23 44 0.997 0.998 53 7 0.12 24 44 0.996 0.998 51 8 0.14 25 44 1.000 0.998 55 6 0.10 26 45 0.998 0.998 54 7 0.11 27 44 0.996 0.998 54 6 0.10 28 44 0.999 0.998 54 6 0.10