JPWO2019125151A5 - - Google Patents

Description

Reactivation of the supported dimer aluminum salen complex can be carried out by recycling the halogenated compound to step (a) as described above and/or by adding fresh halogenated compound. can. Reactivation of the supported dimer aluminum salen complex is preferably carried out in a separate step (e). In such step (e), the supported dimeric aluminum salen complex used in step (a) is contacted with a halogenated compound, resulting in reactivation of the deactivated complex. Preferably no carbon dioxide and/or epoxide is added to the reactivation step (e). Dissolved carbon dioxide and/or epoxide added to the complex in step (a) may still be present. Preferably, a portion of the cyclic carbonate product present as reaction medium in step (a) is separated from the supported dimer aluminum salen complex. This can be done by the separation means used in step (b). This results in a suspension of liquid cyclic carbonate and supported dimeric aluminum-salen complex that is richer in supported dimeric aluminum-salen complex compared to the suspension of step (a). The molar ratio of the halogenated compound to the dimer aluminum salen complex in this suspension in step (e) is greater than 5:1, preferably greater than 7:1 in step (e).

When performing step (e), it is preferred to save the halogenated compound obtained in step (c) and to recycle the carbon dioxide and optionally the epoxide compound obtained in step (c). The stored halide may then be used in another step (e). Step (e) may be performed in different modes. For example, the reactor in which step (a) is carried out can be regenerated in step (e). There, the supported dimer aluminum salen complex remains in the reactor and the halogenated compound is fed to the reactor. This results in the reactor temporarily not preparing cyclic carbonates as it is in its regeneration mode. In such modes it is preferred to have at least more than one reactor operating in parallel, wherein steps (a) and (e) are performed alternately in the reactors and step (e) is performed in one or more reactor, while step (a) is performed in one or more of the remaining reactors.

Claims (20)

A process for continuously preparing a cyclic carbonate product by reacting an epoxide compound with carbon dioxide in the presence of a supported dimeric aluminum salen complex activated by a halogenated compound, comprising: the process of
(a) carbon dioxide is contacted with an epoxide compound in a suspension of a liquid cyclic carbonate and a supported dimeric aluminum salen complex activated by a halogenated compound, wherein the epoxide compound is a dioxide reacting with carbon to a cyclic carbonate product and partially deactivating the supported dimeric salen complex;
(b) separating a portion of the cyclic carbonate product from the supported dimer aluminum salen complex to obtain a mixture comprising the cyclic carbonate product, carbon dioxide, the epoxide compound and the halogenated compound;
(c) separating the halogenated compound from the cyclic carbonate product to obtain a purified cyclic carbonate product; and (d) using all or a portion of the halogenated compound obtained in step (c). , activating the deactivated supported dimeric salen complex. Claim 1, wherein the temperature in step (a) is between 20 and 150°C, the pressure is between 0.1 and 0.5 MPa, and the temperature is below the boiling point of the product at the selected pressure. The method described in . wherein said step (a) is a continuously operated stirred reaction wherein carbon dioxide and epoxide compound are continuously fed to the reactor and a portion of the cyclic carbonate product is continuously withdrawn as part of the liquid stream; 3. The method of claim 1 or 2, performed in a vessel. The method of any one of claims 1-3, wherein the epoxide compound has 2-8 carbon atoms. 5. The method of claim 4, wherein the epoxide compound is ethylene oxide, propylene oxide, butylene oxide, pentene oxide, glycidol or styrene oxide. Process according to any one of claims 1 to 5, wherein the separation of step (b) utilizes different mass densities and/or sizes between the cyclic carbonate and the supported dimer aluminum salen complex. . 7. The method of claim 6, wherein the separation of step (b) is performed by a filter. 7. The method of claim 6, wherein the separating in step (b) is performed using centrifugal force. Said step (c) is carried out by distillation, in which the mixture comprising carbon dioxide, the halogenated compound, the epoxide compound and the cyclic carbonate product is separately separated from the carbon dioxide, the halogenated compound, the epoxide compound and the cyclic carbonate product. The method according to any one of claims 1 to 8, wherein the stream is separated into a stream of 3. The content of epoxide compounds in the mixture obtained in step (b) is reduced to obtain a mixture with reduced epoxide content, and the mixture obtained is separated in a distillation step (c). 9. The method according to 9. 11. The method of claim 10, wherein the epoxide compound reduction is achieved in the second reaction step by contacting the epoxide compound with carbon dioxide in the presence of a supported dimeric aluminum salen complex. 12. The method of any one of claims 1-11, wherein the deactivated supported dimeric aluminum salen complex is activated by contact with a halogenated compound while performing step (a). Method. by contacting the deactivated supported dimer aluminum salen complex with a halogenated compound in the presence of a cyclic carbonate product ; A method according to any one of claims 1 to 11, activated in a step (e) separate from (a) . 14. The method of claim 13, wherein the molar ratio of said halogenated compound to supported dimer aluminum salen complex is greater than 5:1 in step (e). When steps (a) and (e) are performed in two or more reactors operated in parallel and step (e) is performed in one or more reactors, step (a) is performed in the remaining reactors. 15. The method of claim 13 or 14, wherein the method is performed in at least one of 16. The method of any one of claims 1-15, wherein the supported dimer aluminum salen complex is represented by the formula:

[wherein S represents a solid support linked to a nitrogen atom via an alkylene group, where the supported dimeric aluminum salen complex is activated by a halogenated compound, and X is tert-butyl , X2 is hydrogen and Et is an alkyl group having 1 to 10 carbon atoms. ] 17. A method according to claim 16, wherein said support S is composed of particles with an average diameter between 10 and 2000 μm. 18. The method of claim 17, wherein said support S is a particle selected from the group consisting of silica, alumina, titania, siliceous MCM-41 or siliceous MCM-48. The method of any one of claims 1-18, wherein the halide is a benzyl halide. 20. The method of claim 19, wherein said benzyl halide is benzyl bromide.