Catalyst Recycle Methods

Abstract

The present invention provides novel solutions to the problem of recycling carbonylation catalysts in epoxide carbonylation processes. The inventive methods are characterized in that the catalyst is recovered in a form other than as active catalyst. In some embodiments, catalyst components are removed selectively from the carbonylation product stream in two or more processing steps. One or more of these separated catalyst components are then utilized to regenerate active catalyst which is utilized during another time interval to feed a continuous carbonylation reactor.

Claims

1. A method for the continuous reaction of an epoxide and carbon monoxide comprising: a) feeding a continuous carbonylation reactor during a first interval of time with a catalyst feed stream comprising a carbonylation catalyst, where within the reactor, the epoxide and the carbon monoxide react in the presence of the carbonylation catalyst to provide a reaction product stream comprising an epoxide carbonylation product and carbonylation catalyst, b) treating the reaction product stream to separate at least a portion of the carbonylation catalyst from the reaction product stream, c) accumulating carbonylation catalyst collected in step (b) throughout the first interval of time to obtain a spent carbonylation catalyst batch, and d) feeding a continuous carbonylation reactor during a second interval of time with a catalyst feed stream wherein at least a portion of the catalyst in the catalyst feed stream is derived from spent carbonylation catalyst batch accumulated in step (c).

2. The method of claim 1, wherein the epoxide is ethylene oxide.

3. The method of claim 2, wherein the epoxide carbonylation product is selected from the group consisting of: beta propiolactone, succinic anhydride, polypropiolactone, 3-hydroxypropionic acid, and a 3-hydroxypropionate ester.

4. The method of claim 2, wherein the epoxide carbonylation product comprises beta propiolactone.

5. The method of claim 1, wherein the carbonylation catalyst comprises a metal carbonyl compound.

6. The method of claim 5, wherein step (b) comprises removing metal carbonyl from the reaction product stream.

7. The method of claim 1, wherein the carbonylation catalyst comprises a metal carbonyl compound in combination with one or more other catalyst components.

8. The method of claim 7, wherein step (b) comprises selectively removing metal carbonyl compound to the at least partial exclusion of other catalyst components.

9. The method of claim 1, wherein the metal carbonyl compound comprises an anionic metal carbonyl in combination with a cationic Lewis acid.

10. The method of claim 9, wherein step (b) comprises selectively removing at least a portion of the anionic metal carbonyl compound from the reaction product stream using an anion exchanging material.

11. The method of claim 9, wherein step (b) comprises selectively removing at least a portion of the cationic Lewis acid from the reaction product stream using a cation exchanging material.

12. The method of claim 9, wherein step (b) comprises treating the reaction product stream using an anion exchanging material to remove metal carbonyl and separately treating the reaction product stream using a cation exchanging material to remove Lewis acid.

13. The method of claim 1, comprising a step of regenerating the accumulated carbonylation catalyst from step (c) before feeding the accumulated carbonylation catalyst in step (d).

14. The method of claim 13, wherein the step of regenerating activates the carbonylation catalyst.

15. The method of claim 13, comprising applying pressure and carbon monoxide to the carbonylation catalyst to regenerate the carbonylation catalyst.

16. The method of claim 13, wherein the carbonylation catalyst is a metal carbonyl that is regenerated by combining the metal carbonyl with a Lewis acid.

17. The method of claim 1, wherein the epoxide is chosen from a group consisting of ethylene oxide, propylene oxide, 1,2-butylen oxide, 2,3-butylene oxide, epichlorohydrin, cyclohexene oxide, cyclopentene oxide, 3,3,3-Trifluoro-1,2-epoxypropane, styrene oxide, a glycidyl ether, and a glycidyl ester.

18. The method of claim 1, wherein the carbonylation catalyst is tetraphenylporphyrinato aluminum carbonyl cobaltate.

19. The method of claim 5, wherein the metal carbonyl is a cobalt carbonyl compound.

20. The method of claim 9, wherein the anionic metal carbonyl is carbonyl cobaltate.

Description

DETAILED DESCRIPTION OF THE INVENTION

Methods of the Invention

[0042] In a first aspect, the present invention provides methods for the continuous reaction of an epoxide and carbon monoxide. The methods utilize a carbonylation reactor in which the epoxide and carbon monoxide are contacted in the presence of a carbonylation catalyst to produce a reaction product stream. Typically, the reactor is fed with at least three input streams: an epoxide feedstream, a carbon monoxide feed, and a catalyst feedstream (though in certain embodiments additional feeds may be present, or two or more streams may be combined to lessen the total number of separate feed streams). The reaction product stream exits the reactor and contains epoxide carbonylation products, the catalyst, and optionally unreacted feedstock, solvent, reaction byproducts and the like. In certain embodiments, the epoxide carbonylation product comprises a beta lactone, a succinic anhydride, or a polyester. In certain embodiments, the epoxide carbonylation product is not a 3-hydroxy propionic acid or a 3-hydroxy propionaldehyde.

[0043] In certain embodiments, methods of the present invention include the steps of: [0044] a) feeding a continuous carbonylation reactor during a first interval of time with a catalyst feed stream comprising a carbonylation catalyst, an epoxide feedstream comprising an epoxide, and carbon monoxide such that within the reactor the epoxide and carbon monoxide react under the influence of the carbonylation catalyst to form a carbonylation reaction product selected from the group consisting of: a beta lactone, a succinic anhydride, or a polyhydroxypropionate, such that a reaction product stream comprising the epoxide carbonylation product and the carbonylation catalyst, continuously exits the reactor, [0045] b) treating the reaction product stream to separate at least a portion of the carbonylation catalyst, [0046] c) accumulating carbonylation catalyst collected in step (b) throughout the first interval of time to obtain a spent carbonylation catalyst batch, [0047] d) feeding a continuous carbonylation reactor during a second interval of time with a catalyst feed stream wherein at least a portion of the catalyst in the catalyst feed stream comprises (or is derived at least in part from) the spent carbonylation catalyst batch accumulated in step (c).

[0048] In certain embodiments, the step of treating the reaction product stream to separate a portion of the carbonylation catalyst entails using a separation mode selected from the group consisting of: precipitation, adsorption, ion exchange, extraction, and any combination of two or more of these.

[0049] In certain embodiments, the step of treating the reaction product stream to separate a portion of the carbonylation catalyst entails precipitating the catalyst. Precipitation of the catalyst can be accomplished by any known means. Suitable means of precipitating the catalyst will be apparent to the skilled chemist and may include, but are not limited to: adding a solvent to the reaction product stream in which the catalyst (or a component thereof) is poorly soluble, cooling the reaction product stream, adding a material that interacts with the catalyst (or a component thereof) to form an insoluble adduct, removing solvent, excess feedstock, or carbon monoxide from the reaction product stream, and combinations of any two or more of these.

[0050] In certain embodiments where the step of treating the reaction product stream to separate a portion of the carbonylation catalyst entails precipitation, the precipitation step comprises adding a solvent in which the catalyst (or a component of the catalyst) is poorly soluble. In certain embodiments, a non-polar solvent such as an aliphatic hydrocarbon, an aromatic hydrocarbon, or condensed phase CO.sub.2 is added to precipitate the catalyst. In certain embodiments, a solvent selected from butane, pentane, hexane, heptane, octane, cyclopentane, cyclohexane, decalin, higher alkanes, and mixtures of two or more alkanes is added to the reaction product stream to precipitate the catalyst or a catalyst component. In certain embodiments, a solvent selected from benzene, toluene, xylene, mesitylene, chlorobenzene, or other substituted benzene compounds is added to the reaction product stream to precipitate the catalyst or a catalyst component. In certain embodiments, supercritical CO.sub.2 is added to the reaction product stream to precipitate the catalyst or a catalyst component. In certain embodiments where the carbonylation catalyst comprises the combination of a Lewis acidic metal complex and a metal carbonyl compound and a non-polar solvent is added to the reaction product stream, this causes precipitation of the Lewis acidic metal complex but leaves at least a portion of the metal carbonyl component of the catalyst behind in the reaction product stream.

[0051] In embodiments where the catalyst is precipitated, the step of separating the carbonylation catalyst typically includes further steps to remove the precipitate from the product stream, such isolation steps are well known in the art and can include, but are not limited to filtration, sedimentation, centrifugation, coagulation, and combinations of two or more of these.

[0052] Therefore, in certain embodiments, the present invention encompasses methods having the steps of: [0053] a) feeding a continuous carbonylation reactor during a first interval of time with a catalyst feed stream comprising a carbonylation catalyst, an epoxide feed stream comprising an epoxide, and carbon monoxide such that within the reactor, the epoxide and carbon monoxide react under the influence of the carbonylation catalyst to form a carbonylation reaction product selected from the group consisting of: a beta lactone, a succinic anhydride, and a polyhydroxypropionate, wherein a reaction product stream comprising the epoxide carbonylation product and the carbonylation catalyst exits the reactor, [0054] b) adding to the reaction product stream a solvent selected from the group consisting of: condensed phase CO.sub.2, an alkane, an aliphatic hydrocarbon, and an aromatic hydrocarbon thereby causing at least a portion of the carbonylation catalyst to precipitate from the reaction product stream and separating the precipitated carbonylation catalyst from the reaction product stream, [0055] c) accumulating carbonylation catalyst collected in step (b) throughout the first interval of time to obtain a spent carbonylation catalyst batch, [0056] d) feeding a continuous carbonylation reactor during a second interval of time with a catalyst feed stream wherein at least a portion of the catalyst in the catalyst feed stream comprises (or is derived at least in part from) the spent carbonylation catalyst batch accumulated in step (c).

[0057] In certain embodiments, the step of treating the reaction product stream to separate carbonylation catalyst comprises adsorbing the catalyst or catalyst components. The step of adsorption can entail treating the reaction product stream with a solid adsorbing material. Suitable solid adsorbing materials include inorganic substances, activated carbon, polymers, resins, or any combination of two or more of these. Suitable inorganic adsorbing materials include silica gel, alumina, silicate minerals, clays, diatomaceous earth, Fuller's earth, ceramics, zirconias, molecular sieves and the like. Suitable polymers include polystyrenes, polyacrylonitrile, polyimides, polyolefins, polyesters, polyethers, polycarbonates, polyisocyanates, and the like. Such polymers optionally include additional chemical functional groups to enhance their ability to adsorb carbonylation catalysts or catalyst components. Such functional groups can include acids (i.e. sulfonic or carboxylic acids), coordinating groups (i.e. amine, thiol, phosphine, nitrile, or boron groups), bases, (for example amine groups or nitrogen heterocycles). In certain cases, the adsorbing materials whether inorganic or polymeric are acidic, basic, or have undergone chemical treatments to enhance the affinity of the catalyst.

[0058] In embodiments where catalyst is removed from the reaction product stream by adsorption, the adsorbant can be contacted with the product stream by any conventional method. This includes, but is not limited to: flowing the reaction product stream through a fixed bed of adsorbent; flowing the reaction product stream through a fluidized bed of adsorbant; flowing the reaction product stream through fabrics, meshes, or filtration plates comprising the adsorbant material; or slurrying the reaction product stream with the adsorbant material (typically followed by filtration, centrifugation, sedimentation or the like to remove the adsorbant from the product stream). In embodiments where the reaction product stream is flowed through a column of adsorbant, it may be desirable to provide a plurality of such columns in parallel with a provision to switch the flow from one column to another. Thus when one column of adsorbant becomes saturated with catalyst, it can be switched out of the flow path and the flow diverted to a fresh columnin certain embodiments, the interval of time from when a column is placed in the flow path to when it is switched out of the flow path corresponds to the first time interval recited in the methods described herein.

[0059] Where an adsorbant is used to remove catalyst from the reaction product stream, the inventive methods will typically include a step of desorbing the catalyst or catalyst component(s) from the adsorbant. Such desorption methods are well known in the art and will vary depending on the identity of the adsorbant and the catalyst. Desorption can include treating with a polar solvent or solute which displaces the catalyst or catalyst component, or can comprise a reactive process where the a reagent is added to the adsorbed catalyst to regenerate it or form a species which is less adhered to the adsorbing solid.

[0060] Therefore, in certain embodiments, the present invention encompasses methods having the steps of: [0061] a) feeding the continuous carbonylation reactor during a first interval of time with a catalyst feed stream comprising a carbonylation catalyst, an epoxide feedstream comprising an epoxide, and carbon monoxide such that within the reactor, the epoxide and carbon monoxide react under the influence of the carbonylation catalyst to provide a reaction product stream exiting the reactor and comprising an epoxide carbonylation product and carbonylation catalyst, [0062] b) contacting the reaction product stream with a solid material which adsorbs at least a portion of the carbonylation catalyst from the reaction product stream, [0063] c) accumulating carbonylation catalyst adsorbed in step (b) throughout the first interval of time and processing it to obtain a spent carbonylation catalyst batch, [0064] d) feeding a continuous carbonylation reactor during a second interval of time with a catalyst feed stream wherein at least a portion of the catalyst in the catalyst feed stream comprises (or is derived at least in part from) the spent carbonylation catalyst batch accumulated in step (c).

[0065] In certain embodiments, the step of treating the reaction product stream to separate carbonylation catalyst comprises ion exchange of the catalyst or catalyst components. In certain embodiments, the step of treating the reaction product stream to separate carbonylation catalyst comprises treating the reaction product stream with ion exchange materials. The ion exchange materials may be cationic, anionic, amphoteric, Lewis basic, Lewis acidic or may comprise chelating groups. In certain embodiments, the ion exchange material may be a cation exchanger. In certain embodiments, functional groups on the cation exchange materials may be selected from the group: SO.sub.3, PO.sub.3.sup.2, COOH, C.sub.6H.sub.4OH, SH, AsO.sub.3, SeO.sub.3, or combinations of two or more of these. In certain embodiments, functional groups on the cation exchange materials comprise SO.sub.3. In certain embodiments, the ion exchange material may be an anion exchanger. In certain embodiments, functional groups on the anion exchange materials may be selected from the group: N.sup.+(alkyl).sub.3, N.sup.+(CH.sub.3).sub.3, N.sup.+(CH.sub.3).sub.2C.sub.2H.sub.4OH, N.sup.+(CH.sub.3).sub.2C.sub.2H.sub.5, P.sup.+(alkyl).sub.3, P.sup.+(aryl).sub.3, P.sup.+(C.sub.4H.sub.9).sub.3, P.sup.+(Ph).sub.3, or combinations of two or more of these. In certain embodiments, functional groups on the anion exchange materials comprise N.sup.+(alkyl).sub.3. In certain embodiments, functional groups on the anion exchange materials comprise P.sup.+(alkyl).sub.3. In certain embodiments, functional groups on the anion exchange materials comprise P.sup.+(aryl).sub.3.

[0066] In certain embodiments where the step of treating the reaction product stream to separate carbonylation catalyst comprises ion exchange, the process entails both anion exchange and cation exchange. In certain embodiments, where the carbonylation catalyst comprises the combination of a cationic Lewis acid and an anionic metal carbonyl, each is removed separately and the method comprises treating the reaction product stream with a cation exchange material to remove the Lewis acid and an anion exchange material to remove the metal carbonyl. In certain embodiments the anion and cation exchange are performed concomitantly. In certain embodiments, the anion and cation exchange are performed sequentially. In certain embodiments, the anion exchange is performed first followed by cation exchange. In certain embodiments, the cation exchange is performed first followed by anion exchange.

[0067] In certain embodiments, an ion exchange material used in the separation step comprises an organic ion exchange resin. Organic ion exchange resins generally possess a three dimensional structure, a matrix. Functional groups maybe attached to the structure, or directly incorporated in the polymeric chains. The matrix may be constructed from linear polymeric chains cross-linked with each other by relatively short links. By way of example, in various aspects, the present disclosure includes the use of ion exchange materials comprised of sulphonated polystyrene cross-linked with divinylbenzene:

##STR00001##

[0068] In various aspects, ion exchange materials may take the form of gels, or gel resins, distributed across a bead, or other support substrate. In various aspects, ion exchange materials may take the form of macroporous resins which have a heterogeneous structure consisting of two phases, a gel region comprised of polymers and macroscopic permanent pores. In various embodiments of the present disclosure, the ion exchange materials comprise macroreticular resins which are additionally macroporous resins in which the gel regions consist of a plurality bead micro-grains. Ion exchange materials may comprise a wide variety of morphologies and forms, including variations in porosity and other surface properties. In various aspects, materials can be formed into, but not limited to beads, pellets, spheres, spheroids, rings, hollow cylinders, blocks, fibers, meshes, membranes, textiles. In various aspects, the bead size may be widely distributed, or may be very narrow, so-called mono-disperse resins.

[0069] In embodiments where catalyst is removed from the reaction product stream by ion exchange, the ion exchange material can be contacted with the product stream by any conventional method. This includes, but is not limited to: flowing the reaction product stream through a fixed bed of a solid ion exchange material (i.e. in the form of beads, granules or other particles); flowing the reaction product stream through a fluidized bed of adsorbant, flowing the reaction product stream through fabrics, meshes, or filtration plates comprising the ion exchange material, or slurrying the reaction product stream with the ion exchange material (typically followed by filtration, centrifugation, sedimentation or the like to remove the ion exchange material from the product stream). In embodiments where the reaction product stream is flowed through a packed column of ion exchange material, it may be desirable to provide a plurality of such columns in parallel with a provision to switch the flow from one to another periodically. Thus when one column of ion exchange material becomes saturated with catalyst, it can be switched out of the flow path and the flow diverted to a fresh columnin certain embodiments, the interval of time from when a column is placed in the flow path to when it is switched out of the flow path corresponds to the first time interval recited in the methods described herein.

[0070] Where an ion exchange material is used to remove catalyst from the reaction product stream, the inventive methods will typically include a subsequent step of removing the catalyst or catalyst component(s) from the ion exchange material. Such removal methods are well known in the art and typically involve contacting the ion exchange resin with a strong solution of a salt, the anion or cation of which will displace the catalyst component from the ion exchange material. The specifics of this removal step will obviously vary depending on the identity of the adsorbant and the catalyst, but suitable methods are widely known to those skilled in the art.

[0071] Therefore, in certain embodiments, the present invention encompasses methods having the steps of: [0072] a) feeding the continuous carbonylation reactor during a first interval of time with a catalyst feed stream comprising a carbonylation catalyst, an epoxide feedstream comprising an epoxide, and carbon monoxide such that within the reactor, the epoxide and carbon monoxide react under the influence of the carbonylation catalyst to provide a reaction product stream exiting the reactor and comprising an epoxide carbonylation product and carbonylation catalyst, [0073] b) contacting the reaction product stream with a first ion exchange material which captures at least one component of the carbonylation catalyst from the reaction product stream, [0074] c) accumulating carbonylation catalyst in step (b) throughout the first interval of time and processing the ion exchange material(s) to obtain a spent carbonylation catalyst batch, and [0075] d) feeding a continuous carbonylation reactor during a second interval of time with a catalyst feed stream wherein at least a portion of the catalyst in the catalyst feed stream comprises (or is derived at least in part from) the spent carbonylation catalyst batch accumulated in step (c).

[0076] In certain embodiments, step (b) of the method includes the further step of treating the reaction product stream with a second ion exchange resin to remove one or more additional components of the carbonylation catalyst from the reaction product stream. In such embodiments, one or both of the ion exchange resins may be processed in step (c) to obtain the spent catalyst batch or batches.

[0077] Therefore, in certain embodiments, the present invention encompasses methods having the steps of: [0078] a) feeding the continuous carbonylation reactor during a first interval of time with a catalyst feed stream comprising a carbonylation catalyst, an epoxide feedstream comprising an epoxide, and carbon monoxide such that within the reactor, the epoxide and carbon monoxide react under the influence of the carbonylation catalyst to provide a reaction product stream exiting the reactor and comprising an epoxide carbonylation product and carbonylation catalyst, [0079] b) contacting the reaction product stream with a first ion exchange material which captures at least one component of the carbonylation catalyst from the reaction product stream, and then treating the reaction product stream with a second ion exchange material that removes one or more additional components from the reaction product stream, wherein if the first ion exchange material is an anion exchanger, then the second ion exchanger is a cation exchanger or vice versa, [0080] c) accumulating the removed carbonylation catalyst in step (b) throughout the first interval of time and processing at least one of the ion exchange materials to obtain a spent carbonylation catalyst batch, and [0081] d) feeding a continuous carbonylation reactor during a second interval of time with a catalyst feed stream wherein at least a portion of the catalyst in the catalyst feed stream comprises (or is derived at least in part from) the spent carbonylation catalyst batch accumulated in step (c).

[0082] In certain embodiments carbonylation catalyst is removed from the reaction product stream by extraction. In such embodiments, the extraction step comprises adding a solvent in which the catalyst (or a component of the catalyst) is soluble. In other embodiments, the extraction solvent is one in which the product is soluble, but which has little tendency to dissolve the carbonylation catalyst (or one or more components of the carbonylation catalyst). Preferably, in either case, the addition of the extraction solvent results in the formation of two phases.

[0083] In certain embodiments, the extraction solvent is a highly polar solvent such as water or an ionic liquid. In certain embodiments, the extraction solvent is supercritical CO.sub.2. In certain embodiments, the extraction solvent is water or an aqueous solution. In certain embodiments, the extraction solvent is an ionic liquid. In certain embodiments where the solvent is an ionic liquid, the ionic liquid has a formula [Cat.sup.+][X] wherein [Cat.sup.+] refers to one or more organic cationic species; and [X] refers to one or more anions. In certain embodiments, [Cat.sup.+] is selected from the group consisting of: ammonium, tetralkylammonium, benzimidazolium, benzofuranium, benzothiophenium, benzotriazolium, borolium, cinnolinium, diazabicyclodecenium, diazabicyclononenium, 1,4-diazabicyclo[2.2.2]octanium, diazabicyclo-undecenium, dithiazolium, furanium, guanidinium, imidazolium, indazolium, indolinium, indolium, morpholinium, oxaborolium, oxaphospholium, oxazinium, oxazolium, iso-oxazolium, oxothiazolium, phospholium, phosphonium, phthalazinium, piperazinium, piperidinium, pyranium, pyrazinium, pyrazolium, pyridazinium, pyridinium, pyrimidinium, pyrrolidinium, pyrrolium, quinazolinium, quinolinium, iso-quinolinium, quinoxalinium, quinuclidinium, selenazolium, sulfonium, tetrazolium, thiadiazolium, iso-thiadiazolium, thiazinium, thiazolium, iso-thiazolium, thiophenium, thiuronium, triazinium, triazolium, iso-triazolium, uronium, and any combination of two or more of these. In accordance with the present invention, [X] may comprise an anion selected from halides, sulphates, sulfonates, sulfonimides, phosphates, phosphonates, carboxylates, CN.sup., NO.sub.3.sup., NO.sub.2.sup., BF.sub.4.sup. and PF.sub.6.sup..

[0084] Therefore, in certain embodiments, the present invention encompasses methods having the steps of: [0085] a) feeding the continuous carbonylation reactor during a first interval of time with a catalyst feed stream comprising a carbonylation catalyst, an epoxide feedstream comprising an epoxide, and carbon monoxide such that within the reactor, the epoxide and carbon monoxide react under the influence of the carbonylation catalyst to provide a reaction product stream exiting the reactor and comprising an epoxide carbonylation product and carbonylation catalyst, [0086] b) adding to the reaction product stream an extraction solvent selected from the group consisting of: water, condensed phase CO.sub.2, and an ionic liquid, thereby causing formation of two phases wherein the carbonylation catalyst (or at least one component of the carbonylation catalyst) is at least to some extent partitioned from the carbonylation reaction product across the two phases, [0087] separating and treating a phase containing carbonylation catalyst (or a component of the carbonylation catalyst) to recover the catalyst or catalyst or catalyst component, [0088] c) accumulating carbonylation catalyst or component collected in step (b) throughout the first time interval to obtain a spent carbonylation catalyst batch, [0089] d) feeding a continuous carbonylation reactor during a second interval of time with a catalyst feed stream wherein at least a portion of the catalyst in the catalyst feed stream comprises (or is derived at least in part from) the spent carbonylation catalyst batch accumulated in step (c).

The Accumulating Step

[0090] As noted above, one of the features of methods of the present invention is accumulation of recovered carbonylation catalyst throughout a time interval. In the present methods, the carbonylation catalyst (or a component thereof) separated from the reaction product stream is accumulated through some interval of time. The accumulated catalyst (or component) forms a spent catalyst batch that is eventually reused (either in whole or in part) in a carbonylation process. The process for which the catalyst is re-used may or may not be the same process from which the catalyst was isolated. Likewise it may be reused for the same process but on another day or in a different reactor. This is in stark contrast to prior art methods wherein the separated catalyst is treated as a stream within the reaction process which is returned to the reactor within a relatively short period.

[0091] One potential advantage of the present methods is the removal of the constraint that the catalyst be recovered in active form. For examples, many carbonylation catalysts used in the processes described herein contain metal carbonyl species which are known to have limited stability under conditions lacking a pressurized atmosphere of CO. Therefore in certain embodiments of the present methods, the carbonlyation catalyst is recovered in a form other than as active catalyst. To complete the catalyst recycle method in such embodiments one or more additional steps to regenerate the catalyst must be performed.

[0092] In certain embodiments, where the carbonylation catalyst comprises a cationic Lewis acid in combination with an anionic metal carbonyl, the cationic Lewis acid portion of the catalyst is captured from the carbonylation stream without the associated metal carbonyl. This is feasible since the Lewis acid portion of the catalyst is typically the most expensive catalyst component. In certain embodiments, the cationic Lewis acid is accumulated in a form with a counterion other than the anionic metal carbonyl. In such embodiments, the methods may include a further step of treating the accumulated batch of cationic Lewis acid under conditions to swap a non metal carbonyl anion associated with the accumulated Lewis acid with a metal carbonyl anion.

[0093] In certain embodiments, where the carbonylation catalyst comprises a cationic Lewis acid in combination with an anionic metal carbonyl, the metal carbonyl portion of the catalyst is captured from the carbonylation stream without the associated Lewis acid. The metal carbonyl thus accumulated may be captured as an anionic metal carbonyl (for example by anion exchange) or it may be accumulated in another form such as a reduced metal species, a metal salt, a neutral metal carbonyl, a mixed metal carbonyl complex, or some other form. In such embodiments, the methods may include a further step of treating the accumulated species to regenerate a catalytically active metal carbonyl compound. In the case where an intact metal carbonyl anion is accumulated (for example by capture on an anion exchange resin), such steps may include metathesis to free the metal carbonyl anion from the resin. This will typically entail flooding the resin with another anion (such as sodium chloride) to displace the metal carbonyl. The metal carbonyl may then be obtained as its sodium salt and utilized to produce active catalyst according to known catalyst synthesis procedures. Therefore, in certain embodiments, methods of the present invention comprise further steps of freeing accumulated metal carbonyl anion from a resin. In certain embodiments, such steps entail further steps of utilizing accumulated metal carbonyl anion to regenerate active catalyst by combining the accumulated metal carbonyl with a suitable Lewis acid.

[0094] In certain embodiments, the metal carbonyl may be accumulated in a form other than as an intact metal carbonyl anion. For example, in CO-deficient atmospheres, the metal carbonyl may lose one or more CO ligands to form multinuclear metal carbonyl species, salts, or precipitate in elemental form. In other embodiments, a strong ligand may utilized to displace one or more CO ligands and aid in capture of the metal carbonyl as a new complex. It is well known that such species can be utilized to regenerate well defined metal carbonyl compounds by treatment under CO pressure. Therefore, in certain embodiments, methods of the present invention include further steps of regenerating the catalytically active metal carbonyl species from a non-catalytically active material accumulated from the reaction product stream. In certain embodiments, such steps entail further steps of treating accumulated residue derived from a catalytically active metal carbonyl compound under conditions to regenerate a catalytically active metal carbonyl suitable for reuse. In certain embodiments, such steps include a step of treating the accumulated residue under high CO pressure. In certain embodiments, methods include the step of treating a cobalt-containing residue accumulated from the reaction product stream under conditions of high CO pressure to convert it to dicobalt octacarbonyl.

[0095] In certain embodiments where the accumulation of catalyst separated from the reaction product stream comprises steps of recovering two or more separate catalyst components in separate recovered catalyst batches, methods of the present invention comprise additional steps of recombining recovered catalyst components to produce active carbonylation catalyst. In some cases the recovered catalyst components may be combined directly while in other steps one or more of the components may require processing as described above prior to the step of combining. In certain embodiments such steps entail a metathesis to recombine a recovered cationic Lewis acid with a recovered metal carbonyl anion such as a carbonyl cobaltate.

[0096] Another feature of the accumulation step is that it occurs during a time interval during which the reactor is being fed and product is being withdrawn, meaning that none of the catalyst accumulated is recycled during the interval. The time interval required to accumulate a batch is dependent on the mode of accumulation, and the scale and economics of any processes required to transform the accumulated catalyst residue into active catalyst. Typically the time interval for accumulation of the catalyst or residue is on the order of hours to days, but may even be weeks. Therefore in certain embodiments of any of the methods described above, the first time interval is in the range from about 1 hour to about 200 hours. In certain embodiments, the first time interval is from about 2 hours to about 8 hours, from about 4 hours to about 16 hours, from about 12 hours to about 24 hours, or from about 16 hours to about 36 hours. In certain embodiments, the first time interval is from about 1 day to about 20 days, from about 1 day to about 3 days, from about 2 days to about 5 days, from about 5 days to about 10 days, or from about 10 days to about 20 days.

[0097] During this time, the carbonylation reactor is fed from a reservoir of catalyst which is depleted as the amount of accumulated catalyst (or catalyst residue) increases on the back end of the process. Additional time is then typically required to process the accumulated catalyst or catalyst residue to remanufacture active catalyst. Therefore some multiple of the first time interval will have elapsed from the first time interval when the catalyst was accumulated to the later time at which the carbonylation reactor is fed with a catalyst feed stream containing catalyst derived from the catalyst accumulated during the first time interval (i.e. step (d)). In certain embodiments the length of time between the second time interval (during with catalyst recovered in step (c) is fed to reactor as recited in step (d) of the methods above), and the first time interval (during which the catalyst was acuumulated) is on the order of about 1 to about 100 times the length of the first time interval. In other words if the first time interval is 10 hours, the second time interval would occur from about 10 hours to about 2000 hours after the completion of the accumulation step. In certain embodiments, the length of time between the second time interval and the first time interval is from about 1 to about 10 times the length of the first time interval. In certain embodiments, the length of time between the second time interval and the first time interval is from about 1 to about 3 times, from about 2 to about 5 times, from about 4 to about 10 times, from about 10 to about 50 times, from about 40 to about 80 times, or from about 50 to about 100 times, the length of the first time interval. In certain embodiments, the length of time between the second time interval and the first time interval is greater than 100 times the first time interval.

Additional Processing Steps

[0098] In certain embodiments, methods encompassed by the present invention comprise additional steps to isolate the carbonylation product from the reaction product stream. These steps are generally executed after step (b) of the methods described above and typically entail further treatment of the product stream from which the catalyst or catalyst component has been substantially removed.

[0099] The precise mode of carrying out the carbonylation product isolation will obviously depend on the character of the carbonylation product. Suitable isolation methods include but are not limited to; distillation, crystallization, precipitation, evaporation, and the like. In embodiments where the carbonylation product is a liquid such as betapropiolactone or betabutyrolactone, the methods may comprise an additional step of performing distillation to separate the lactone from other components of the reaction product stream. Such other components can include solvent(s), unreacted epoxide, reaction byproducts, catalyst residues and the like. In embodiments where the solvent has a lower boiling point than the lactone, or where unreacted epoxide is present, the beta lactone may be retained as the bottoms in the distillation with the solvent and/or epoxide taken to the vapor phase. In embodiments, where the solvent has a boiling point higher than the lactone and/or where involatile catalyst residues are present, the lactone may be taken to the vapor phase. In certain embodiments the catalyst and/or unreacted epoxide are captured and fed back to the epoxide carbonylation reactor (either in real time, or via accumulation and use ata later time).

[0100] In embodiments where the carbonylation product is a solid such as succinic anhydride or polypropiolactone, the methods may comprise an additional step of performing a crystallization or precipitation to separate the carbonylation product from other components of the reaction product stream. Such other components can include solvent(s), unreacted epoxide, reaction byproducts, catalyst residues and the like. In certain embodiments, such methods include a step of lowering the temperature of the reaction product stream. In certain embodiments, such methods include removing solvent, excess epoxide and/or unreacted CO from the reaction product stream. In certain embodiments, such methods comprise adding a solvent to the reaction product stream to cause precipitation or crystallization of the carbonylation product.

[0101] In certain embodiments, the methods described above may include additional steps intermediate between the carbonylation reactions in step (a) and the catalyst separations in step (b). In certain embodiments, such steps include reduction of the CO pressure. In certain embodiments, the CO pressure is reduced to atmospheric pressure. In certain embodiments, excess CO is removed by exposure to sub-atmospheric pressures or by sweeping with another gas. In certain embodiments, the CO thus liberated is captured for re-use or is incinerated to provide heat. In certain embodiments, the methods comprise heating or cooling the reaction product stream between steps (a) and (b). When methods include separation of a solid carbonylation product, they will typically include additional substeps such as filtration, washing and collection of the solid product.

Epoxide Feedstock

[0102] In certain embodiments, the epoxide in the epoxide feedstream in any of the methods described above has a formula:

##STR00002##

where, [0103] R.sup.1 and R.sup.2 are each independently selected from the group consisting of: H; optionally substituted C.sub.1-6 aliphatic; optionally substituted phenyl; optionally substituted C.sub.1-6 heteroaliphatic; optionally substituted 3- to 6-membered carbocycle; and optionally substituted 3- to 6-membered heterocycle, where R.sup.1 and R.sup.2 can optionally be taken together with intervening atoms to form a 3- to 10-membered, substituted or unsubstituted ring optionally containing one or more heteroatoms.

[0104] In some embodiments, R.sup.1 is hydrogen. In some embodiments, R.sup.1 is phenyl. In some embodiments, R.sup.1 is optionally substituted C.sub.1-6 aliphatic. In some embodiments, R.sup.1 is n-butyl. In some embodiments, R.sup.1 is n-propyl. In some embodiments, R.sup.1 is ethyl. In some embodiments, R.sup.1 is CF.sub.3. In some embodiments, R.sup.1 is CH.sub.2Cl. In other embodiments, R.sup.1 is methyl.

[0105] In some embodiments, R.sup.2 is hydrogen. In some embodiments, R.sup.2 is optionally substituted C.sub.1-6 aliphatic. In some embodiments, R.sup.2 is methyl.

[0106] In certain embodiments, R.sup.1 and R.sup.2 are taken together with intervening atoms to form a 3- to 10-membered, substituted or unsubstituted ring optionally containing one or more heteroatoms. In some embodiments, R.sup.1 and R.sup.2 are taken together with intervening atoms to form a cyclopentyl or cyclohexyl ring.

[0107] In certain embodiments, an epoxide is chosen from the group consisting of: ethylene oxide, propylene oxide, 1,2-butylene oxide, 2,3-butylene oxide, epichlorohydrin, cyclohexene oxide, cyclopentene oxide, 3,3,3-Trifluoro-1,2-epoxypropane, styrene oxide, a glycidyl ether, and a glycidyl ester.

[0108] In certain embodiments, the epoxide is ethylene oxide.

[0109] In certain embodiments, the epoxide is propylene oxide.

[0110] In certain embodiments, the carbonylation reaction occurring in the reactor in step (a) conforms to Scheme 2:

##STR00003## [0111] where, each of R.sup.1 and R.sup.2 is as defined above and described in classes and subclasses herein.

[0112] In certain embodiments, the carbonylation reaction conforms to Scheme 3:

##STR00004## [0113] where, R.sup.1 is selected from the group consisting of H and C.sub.1-6 aliphatic.

[0114] In certain embodiments, the carbonylation reaction conforms to Scheme 4 where the epoxide is propylene oxide and the carbonylation product is beta butyrolactone:

##STR00005##

[0115] In certain embodiments, the carbonylation reaction comprises the reaction shown in Scheme 5 where the epoxide is ethylene oxide and the carbonylation product is betapropiolactone:

##STR00006##

[0116] In certain embodiments, the carbonylation reaction occurring in the reactor in step (a) conforms to Scheme 6:

##STR00007## [0117] where, each of R.sup.1 and R.sup.2 is as defined above and described in classes and subclasses herein.

[0118] In certain embodiments, the carbonylation reaction conforms to Scheme 7:

##STR00008## [0119] where, R.sup.1 is selected from the group consisting of H and C.sub.1-6 aliphatic.

[0120] In certain embodiments, the carbonylation reaction conforms to Scheme 8 where the epoxide is propylene oxide and the carbonylation product is methylsuccinic anhydride:

##STR00009##

[0121] In certain embodiments, the carbonylation reaction comprises the reaction shown in Scheme 9 where the epoxide is ethylene oxide and the carbonylation product is succinic anhydride:

##STR00010##

[0122] In certain embodiments, the carbonylation reaction conforms to Scheme 10 where the epoxide is propylene oxide and the carbonylation product is polyhydroxybutyrate:

##STR00011##

[0123] In certain embodiments, the carbonylation reaction comprises the reaction shown in Scheme 11 where the epoxide is ethylene oxide and the carbonylation product is polypropiolactone:

##STR00012##

[0124] The carbon monoxide can be provide to the reactor in step (a) either as a pure stream or as a mixture of carbon monoxide and one or more additional gasses. In some embodiments, carbon monoxide is provided in a mixture with hydrogen (e.g., Syngas). The ratio of carbon monoxide and hydrogen can be any ratio, including by not limited to about 1:1, 1:2, 1:4, 1:10, 10:1, 4:1, 2:1 or a ratio between any two of these values. In some embodiments, the carbon monoxide is provided in mixture with gases as an industrial process gas.

Catalyst

[0125] Numerous carbonylation catalysts known in the art are suitable for (or can be adapted to) methods of the present invention. For example, in certain embodiments, the carbonylation methods utilize a metal carbonyl-Lewis acid catalyst such as those described in U.S. Pat. No. 6,852,865. In other embodiments, the carbonylation step is performed with one or more of the carbonylation catalysts disclosed in U.S. patent application Ser. No. 10/820,958; and Ser. No. 10/586,826. In other embodiments, the carbonylation step is performed with one or more of the catalysts disclosed in U.S. Pat. Nos. 5,310,948; 7,420,064; and 5,359,081. Additional catalysts for the carbonylation of epoxides are discussed in a review in Chem. Commun., 2007, 657-674. The entirety of each of the preceding references is incorporated herein by reference.

[0126] In certain embodiments, the carbonylation catalyst includes a metal carbonyl compound. Typically, a single metal carbonyl compound is provided, but in certain embodiments, mixtures of two or more metal carbonyl compounds are provided. (Thus, when a provided metal carbonyl compound comprises, e.g., a neutral metal carbonyl compound, it is understood that the provided metal carbonyl compound can be a single neutral metal carbonyl compound, or a neutral metal carbonyl compound in combination with one or more metal carbonyl compounds.) Preferably, the provided metal carbonyl compound is capable of ring-opening an epoxide and facilitating the insertion of CO into the resulting metal carbon bond. Metal carbonyl compounds with this reactivity are well known in the art and are used for laboratory experimentation as well as in industrial processes such as hydroformylation.

[0127] In certain embodiments, a provided metal carbonyl compound comprises an anionic metal carbonyl moiety. In other embodiments, a provided metal carbonyl compound comprises a neutral metal carbonyl compound. In certain embodiments, a provided metal carbonyl compound comprises a metal carbonyl hydride or a hydrido metal carbonyl compound. In some embodiments, a provided metal carbonyl compound acts as a pre-catalyst which reacts in situ with one or more reaction components to provide an active species different from the compound initially provided. Such pre-catalysts are specifically encompassed by the present invention as it is recognized that the active species in a given reaction may not be known with certainty; thus the identification of such a reactive species in situ does not itself depart from the spirit or teachings of the present invention.

[0128] In certain embodiments, the metal carbonyl compound comprises an anionic metal carbonyl species. In certain embodiments, such anionic metal carbonyl species have the general formula [Q.sub.dM.sub.e(CO).sub.w].sup.y, where Q is any ligand and need not be present, M is a metal atom, d is an integer between 0 and 8 inclusive, e is an integer between 1 and 6 inclusive, w is a number such as to provide the stable anionic metal carbonyl complex, and y is the charge of the anionic metal carbonyl species. In certain embodiments, the anionic metal carbonyl has the general formula [QM(CO).sub.w].sup.y, where Q is any ligand and need not be present, M is a metal atom, w is a number such as to provide the stable anionic metal carbonyl, and y is the charge of the anionic metal carbonyl.

[0129] In certain embodiments, the anionic metal carbonyl species include monoanionic carbonyl complexes of metals from groups 5, 7 or 9 of the periodic table or dianionic carbonyl complexes of metals from groups 4 or 8 of the periodic table. In some embodiments, the anionic metal carbonyl compound contains cobalt or manganese. In some embodiments, the anionic metal carbonyl compound contains rhodium. Suitable anionic metal carbonyl compounds include, but are not limited to: [Co(CO).sub.4].sup., [Ti(CO).sub.6].sup.2[V(CO).sub.6].sup.[Rh(CO).sub.4].sup., [Fe(CO).sub.4].sup.2[Ru(CO).sub.4].sup.2, [Os(CO).sub.4].sup.2[Cr.sub.2(CO).sub.10].sup.2[Fe.sub.2(CO).sub.8].sup.2[Tc(CO).sub.5].sup.[Re(CO).sub.5].sup. and [Mn(CO).sub.5].sup.. In certain embodiments, the anionic metal carbonyl comprises [Co(CO).sub.4].sup.. In some embodiments, a mixture of two or more anionic metal carbonyl complexes may be present in the carbonylation catalysts used in the methods.

[0130] The term such as to provide a stable anionic metal carbonyl for [Q.sub.dM.sub.e(CO).sub.w].sup.y is used herein to mean that [Q.sub.dM.sub.e(CO).sub.w].sup.y is a species characterizable by analytical means, e.g., NMR, IR, X-ray crystallography, Raman spectroscopy and/or electron spin resonance (EPR) and isolable in catalyst form in the presence of a suitable cation or a species formed in situ. It is to be understood that metals which can form stable metal carbonyl complexes have known coordinative capacities and propensities to form polynuclear complexes which, together with the number and character of optional ligands Q that may be present and the charge on the complex will determine the number of sites available for CO to coordinate and therefore the value of w. Typically, such compounds conform to the 18-electron rule. Such knowledge is within the grasp of one having ordinary skill in the arts pertaining to the synthesis and characterization of metal carbonyl compounds.

[0131] In embodiments where the provided metal carbonyl compound is an anionic species, one or more cations must also necessarily be present. The present invention places no particular constraints on the identity of such cations. In certain embodiments, the cation associated with an anionic metal carbonyl compound comprises a reaction component of another category described hereinbelow. For example, in certain embodiments, the metal carbonyl anion is associated with a cationic Lewis acid. In other embodiments a cation associated with a provided anionic metal carbonyl compound is a simple metal cation such as those from Groups 1 or 2 of the periodic table (e.g. Na.sup.+, Li.sup.+, K.sup.+, Mg.sup.2+ and the like). In other embodiments a cation associated with a provided anionic metal carbonyl compound is a bulky non electrophilic cation such as an onium salt (e.g. Bu.sub.4N.sup.+, PPN.sup.+, Ph.sub.4P.sup.+ Ph.sub.4As.sup.+, and the like). In other embodiments, a metal carbonyl anion is associated with a protonated nitrogen compound (e.g. a cation may comprise a compound such as MeTBD-H.sup.+, DMAP-H.sup.+, DABCO-H.sup.+, DBU-H.sup.+ and the like). In certain embodiments, compounds comprising such protonated nitrogen compounds are provided as the reaction product between an acidic hydrido metal carbonyl compound and a basic nitrogen-containing compound (e.g. a mixture of DBU and HCo(CO).sub.4).

[0132] In certain embodiments, a catalyst utilized in the methods described above comprises a neutral metal carbonyl compound. In certain embodiments, such neutral metal carbonyl compounds have the general formula Q.sub.dM.sub.e(CO).sub.w, where Q is any ligand and need not be present, M is a metal atom, d is an integer between 0 and 8 inclusive, e is an integer between 1 and 6 inclusive, and w is a number such as to provide the stable neutral metal carbonyl complex. In certain embodiments, the neutral metal carbonyl has the general formula QM(CO).sub.w. In certain embodiments, the neutral metal carbonyl has the general formula M(CO).sub.w. In certain embodiments, the neutral metal carbonyl has the general formula QM.sub.2(CO).sub.w. In certain embodiments, the neutral metal carbonyl has the general formula M.sub.2(CO).sub.w. Suitable neutral metal carbonyl compounds include, but are not limited to: Ti(CO).sub.7; V.sub.2(CO).sub.12; Cr(CO).sub.6; Mo(CO).sub.6; W(CO).sub.6Mn.sub.2(CO).sub.10, Tc.sub.2(CO).sub.10, and Re.sub.2(CO).sub.10Fe(CO).sub.5, Ru(CO).sub.5 and Os(CO).sub.5Ru.sub.3(CO).sub.12, and Os.sub.3(CO).sub.12Fe.sub.3(CO).sub.12 and Fe.sub.2(CO).sub.9Co.sub.4(CO).sub.12, Rh.sub.4(CO).sub.12, Rh.sub.6(CO).sub.16, and Ir.sub.4(CO).sub.12Co.sub.2(CO).sub.8Ni(CO).sub.4.

[0133] The term such as to provide a stable neutral metal carbonyl for Q.sub.dM.sub.e(CO).sub.w is used herein to mean that Q.sub.dM.sub.e(CO).sub.w is a species characterizable by analytical means, e.g., NMR, IR, X-ray crystallography, Raman spectroscopy and/or electron spin resonance (EPR) and isolable in pure form or a species formed in situ. It is to be understood that metals which can form stable metal carbonyl complexes have known coordinative capacities and propensities to form polynuclear complexes which, together with the number and character of optional ligands Q that may be present will determine the number of sites available for CO to coordinate and therefore the value of w. Typically, such compounds conform to stoichiometries conforming to the 18-electron rule. Such knowledge is within the grasp of one having ordinary skill in the arts pertaining to the synthesis and characterization of metal carbonyl compounds.

[0134] In certain embodiments, no ligands Q are present on the metal carbonyl compound. In other embodiments, one or more ligands Q are present on the metal carbonyl compound. In certain embodiments, where Q is present, each occurrence of Q is selected from the group consisting of phosphine ligands, amine ligands, cyclopentadienyl ligands, heterocyclic ligands, nitriles, phenols, and combinations of two or more of these. In certain embodiments, one or more of the CO ligands of any of the metal carbonyl compounds described above is replaced with a ligand Q. In certain embodiments, Q is a phosphine ligand. In certain embodiments, Q is a triaryl phosphine. In certain embodiments, Q is trialkyl phosphine. In certain embodiments, Q is a phosphite ligand. In certain embodiments, Q is an optionally substituted cyclopentadienyl ligand. In certain embodiments, Q is cp. In certain embodiments, Q is cp*. In certain embodiments, Q is an amine or a heterocycle.

[0135] In certain embodiments, the carbonylation catalyst utilized in the methods described above further includes a Lewis acidic component. In some embodiments, the carbonylation catalyst includes an anionic metal carbonyl complex and a cationic Lewis acidic component. In certain embodiments, the metal carbonyl complex includes a carbonyl cobaltate and the Lewis acidic co-catalyst includes a metal-centered cationic Lewis acid. In certain embodiments, an included Lewis acid comprises a boron compound.

[0136] In certain embodiments, where an included Lewis acid comprises a boron compound, the boron compound comprises a trialkyl boron compound or a triaryl boron compound. In certain embodiments, an included boron compound comprises one or more boron-halogen bonds. In certain embodiments, where an included boron compound comprises one or more boron-halogen bonds, the compound is a dialkyl halo boron compound (e.g. R.sub.2BX), a dihalo monoalkly compound (e.g. RBX.sub.2), an aryl halo boron compound (e.g. Ar.sub.2BX or ArBX.sub.2), or a trihalo boron compound (e.g. BCl.sub.3 or BBr.sub.3).

[0137] In certain embodiments, where the included Lewis acid comprises a metal-centered cationic Lewis acid, the Lewis acid is a cationic metal complex. In certain embodiments, the cationic metal complex has its charge balanced either in part, or wholly by one or more anionic metal carbonyl moieties. Suitable anionic metal carbonyl compounds include those described above. In certain embodiments, there are 1 to 17 such anionic metal carbonyls balancing the charge of the metal complex. In certain embodiments, there are 1 to 9 such anionic metal carbonyls balancing the charge of the metal complex. In certain embodiments, there are 1 to 5 such anionic metal carbonyls balancing the charge of the metal complex. In certain embodiments, there are 1 to 3 such anionic metal carbonyls balancing the charge of the metal complex.

[0138] In certain embodiments, where carbonylation catalysts used in methods of the present invention include a cationic metal complex, the metal complex has the formula [(L.sup.c).sub.vM.sub.b].sup.z+, where: [0139] L.sup.c is a ligand where, when two or more L.sup.c are present, each may be the same or different; [0140] M is a metal atom where, when two M are present, each may be the same or different; [0141] v is an integer from 1 to 4 inclusive; [0142] b is an integer from 1 to 2 inclusive; and [0143] z is an integer greater than 0 that represents the cationic charge on the metal complex.

[0144] In certain embodiments, provided Lewis acids conform to structure I:

##STR00013##

wherein:

##STR00014## [0145] is a multidentate ligand; [0146] M is a metal atom coordinated to the multidentate ligand; [0147] a is the charge of the metal atom and ranges from 0 to 2; and

[0148] In certain embodiments, provided metal complexes conform to structure II:

##STR00015## [0149] Where a is as defined above (each a may be the same or different), and [0150] M.sup.1 is a first metal atom; [0151] M.sup.2 is a second metal atom;

##STR00016## [0152] comprises a multidentate ligand system capable of coordinating both metal atoms.

[0153] For sake of clarity, and to avoid confusion between the net and total charge of the metal atoms in complexes I and II and other structures herein, the charge (a.sup.+) shown on the metal atom in complexes I and II above represents the net charge on the metal atom after it has satisfied any anionic sites of the multidentate ligand. For example, if a metal atom in a complex of formula I were Cr(III), and the ligand were porphyrin (a tetradentate ligand with a charge of 2), then the chromium atom would have a net chage of +1, and a would be 1.

[0154] Suitable multidentate ligands include, but are not limited to: porphyrin derivatives 1, salen derivatives 2, dibenzotetramethyltetraaza[14]annulene (tmtaa) derivatives 3, phthalocyaninate derivatives 4, derivatives of the Trost ligand 5, tetraphenylporphyrin derivatives 6, and corrole derivatives 7. In certain embodiments, the multidentate ligand is a salen derivative. In other embodiments, the multidentate ligand is a porphyrin derivative. In other embodiments, the multidentate ligand is a tetraphenylporphyrin derivative. In other embodiments, the multidentate ligand is a corrole derivative.

##STR00017## ##STR00018## [0155] where each of R.sup.c, R.sup.d, R.sup.a, R.sup.1a, R.sup.2a, R.sup.3a, R.sup.1a, R.sup.2a, R.sup.3a, and M, is as defined and described in the classes and subclasses herein.

[0156] In certain embodiments, Lewis acids provided carbonylation catalysts used in methods of the present invention comprise metal-porphinato complexes. In certain embodiments, the moiety

##STR00019##

has the structure:

##STR00020## [0157] where each of M and a is as defined above and described in the classes and subclasses herein, and [0158] R.sup.d at each occurrence is independently hydrogen, halogen, OR.sup.4, NR.sup.y.sub.2, SR, CN, NO.sub.2, SO.sub.2R.sup.y, SOR.sup.y, SO.sub.2NR.sup.y.sub.2; CNO, NRSO.sub.2R.sup.y, NCO, N.sub.3, SiR.sub.3; or a optionally substituted group selected from the group consisting of C.sub.1-20 aliphatic; C.sub.1-20 heteroaliphatic having 1-4 heteroatoms independently selected from the group consisting of nitrogen, oxygen, and sulfur; 6- to 10-membered aryl; 5- to 10-membered heteroaryl having 1-4 heteroatoms independently selected from nitrogen, oxygen, and sulfur; and 4- to 7-membered heterocyclic having 1-2 heteroatoms independently selected from the group consisting of nitrogen, oxygen, and sulfur, where two or more R.sup.d groups may be taken together to form one or more optionally substituted rings, where each R.sup.y is independently hydrogen, an optionally substituted group selected the group consisting of acyl; carbamoyl, arylalkyl; 6- to 10-membered aryl; C.sub.1-12 aliphatic; C.sub.1-12 heteroaliphatic having 1-2 heteroatoms independently selected from the group consisting of nitrogen, oxygen, and sulfur; 5- to 10-membered heteroaryl having 1-4 heteroatoms independently selected from the group consisting of nitrogen, oxygen, and sulfur; 4- to 7-membered heterocyclic having 1-2 heteroatoms independently selected from the group consisting of nitrogen, oxygen, and sulfur; an oxygen protecting group; and a nitrogen protecting group; two R.sup.y on the same nitrogen atom are taken with the nitrogen atom to form an optionally substituted 4- to 7-membered heterocyclic ring having 0-2 additional heteroatoms independently selected from the group consisting of nitrogen, oxygen, and sulfur; and each R.sup.4 independently is a hydroxyl protecting group or R.sup.y.

[0159] In certain embodiments, the moiety

##STR00021##

has the structure:

##STR00022## [0160] where M, a and R.sup.d are as defined above and in the classes and subclasses herein.

[0161] In certain embodiments, the moiety

##STR00023##

has the structure:

##STR00024## [0162] where M, a and R.sup.d are as defined above and in the classes and subclasses herein.

[0163] In certain embodiments, Lewis acids included in carbonylation catalysts used in methods of the present invention comprise metallo salenate complexes. In certain embodiments, the moiety

##STR00025##

has the structure:

##STR00026##

wherein: [0164] M, and a are as defined above and in the classes and subclasses herein. [0165] R.sup.1a, R.sup.1a, R.sup.2a, R.sup.2a, R.sup.3a, and R.sup.3a are independently hydrogen, halogen, OR.sup.4, NR.sup.y.sub.2, SR, CN, NO.sub.2, SO.sub.2R.sup.y, SOR, SO.sub.2NR.sup.y.sub.2; CNO, NRSO.sub.2R.sup.y, NCO, N.sub.3, SiR.sub.3; or an optionally substituted group selected from the group consisting of C.sub.1-20 aliphatic; C.sub.1-20 heteroaliphatic having 1-4 heteroatoms independently selected from the group consisting of nitrogen, oxygen, and sulfur; 6- to 10-membered aryl; 5- to 10-membered heteroaryl having 1-4 heteroatoms independently selected from nitrogen, oxygen, and sulfur; and 4- to 7-membered heterocyclic having 1-2 heteroatoms independently selected from the group consisting of nitrogen, oxygen, and sulfur; wherein each R, R.sup.4, and R.sup.y is independently as defined above and described in classes and subclasses herein, [0166] wherein any of (R.sup.2a and R.sup.3a), (R.sup.2a and R.sup.3a), (R.sup.1a and R.sup.2a), and (R.sup.1a and R.sup.2a) may optionally be taken together with the carbon atoms to which they are attached to form one or more rings which may in turn be substituted with one or more R groups; and [0167] R.sup.4a is selected from the group consisting of:

##STR00027##

where [0168] R.sup.c at eah occurrence is independently hydrogen, halogen, OR, NR.sup.y.sub.2, SR.sup.y, CN, NO.sub.2, SO.sub.2R.sup.y, SOR.sup.y, SO.sub.2NR.sup.y.sub.2; CNO, NRSO.sub.2R.sup.y, NCO, N.sub.3, SiR.sub.3; or an optionally substituted group selected from the group consisting of C.sub.1-20 aliphatic; C.sub.1-20 heteroaliphatic having 1-4 heteroatoms independently selected from the group consisting of nitrogen, oxygen, and sulfur; 6- to 10-membered aryl; 5- to 10-membered heteroaryl having 1-4 heteroatoms independently selected from nitrogen, oxygen, and sulfur; and 4- to 7-membered heterocyclic having 1-2 heteroatoms independently selected from the group consisting of nitrogen, oxygen, and sulfur;
where: [0169] two or more R.sup.c groups may be taken together with the carbon atoms to which they are attached and any intervening atoms to form one or more rings; [0170] when two R.sup.c groups are attached to the same carbon atom, they may be taken together along with the carbon atom to which they are attached to form a moiety selected from the group consisting of: a 3- to 8-membered spirocyclic ring, a carbonyl, an oxime, a hydrazone, an imine; and an optionally substituted alkene; [0171] Y is a divalent linker selected from the group consisting of: NR.sup.y, N(R)C(O), C(O)NR.sup.y, O, C(O(, OC(O), C(O)O, S, SO, SO.sub.2, C(S), C(NR.sup.y), NN; a C.sub.3 to C.sub.8 substituted or unsubstituted carbocycle; and a C.sub.1 to C.sub.8 substituted or unsubstituted heterocycle; [0172] m is 0 or an integer from 1 to 4, inclusive; [0173] q is 0 or an integer from 1 to 4, inclusive; and [0174] x is 0, 1, or 2.

[0175] In certain embodiments, a provided Lewis acid comprises a metallo salen compound, as shown in formula Ia:

##STR00028## [0176] wherein each of M, R.sup.d, and a, is as defined above and in the classes and subclasses herein,

##STR00029## [0177] represents is an optionally substituted moiety linking the two nitrogen atoms of the diamine portion of the salen ligand, where

##STR00030##

is selected from the group consisting of a C.sub.3-C.sub.14 carbocycle, a C.sub.6-C.sub.10 aryl group, a C.sub.3-C.sub.14 heterocycle, and a C.sub.5-C.sub.10 heteroaryl group; or an optionally substituted C.sub.2-20 aliphatic group, wherein one or more methylene units are optionally and independently replaced by NR.sup.y, N(R.sup.y)C(O), C(O)N(R.sup.y), OC(O)N(R.sup.y), N(R.sup.y)C(O)O, OC(O)O, O, C(O), OC(O), C(O)O, S, O, SO.sub.2, C(S), C(NR.sup.y), C(NOR.sup.y) or NN.

[0178] In certain embodiments metal complexes having formula Ia above, at least one of the phenyl rings comprising the salicylaldehyde-derived portion of the metal complex is independently selected from the group consisting of:

##STR00031## ##STR00032## ##STR00033## ##STR00034##

[0179] In certain embodiments, a provided Lewis acid comprises a metallo salen compound, conforming to one of formulae Va or Vb:

##STR00035## [0180] where M, a, R.sup.d, R.sup.1a, R.sup.3a, R.sup.1a, R.sup.3a, and

##STR00036##

are as defined above and in the classes and subclasses herein.

[0181] In certain embodiments of metal complexes having formulae Va or Vb, each R.sup.1 and R.sup.3 is, independently, optionally substituted C.sub.1-C.sub.20 aliphatic.

[0182] In certain embodiments, the moiety

##STR00037##

comprises an optionally substituted 1,2-phenyl moiety.

[0183] In certain embodiments, Lewis acids included in carbonylation catalysts used in methods of the present invention comprise metal-tmtaa complexes. In certain embodiments, the moiety

##STR00038##

has the structure:

##STR00039## [0184] where M, a and R.sup.d are as defined above and in the classes and subclasses herein, and [0185] R.sup.e at each occurrence is independently hydrogen, halogen, OR, NR.sub.2, SR, CN, NO.sub.2, SO.sub.2R, SOR, SO.sub.2NR.sub.2; CNO, NRSO.sub.2R, NCO, N.sub.3, SiR.sub.3; or an optionally substituted group selected from the group consisting of C.sub.1-20 aliphatic; C.sub.1-20 heteroaliphatic having 1-4 heteroatoms independently selected from the group consisting of nitrogen, oxygen, and sulfur; 6- to 10-membered aryl; 5- to 10-membered heteroaryl having 1-4 heteroatoms independently selected from nitrogen, oxygen, and sulfur; and 4- to 7-membered heterocyclic having 1-2 heteroatoms independently selected from the group consisting of nitrogen, oxygen, and sulfur.

[0186] In certain embodiments, the moiety

##STR00040##

has the structure:

##STR00041## [0187] where each of M, a, R.sup.c and R.sup.d is as defined above and in the classes and subclasses herein.

[0188] In certain embodiments, where carbonylation catalysts used in methods of the present invention include a Lewis acidic metal complex, the metal atom is selected from the periodic table groups 2-13, inclusive. In certain embodiments, M is a transition metal selected from the periodic table groups 4, 6, 11, 12 and 13. In certain embodiments, M is aluminum, chromium, titanium, indium, gallium, zinc cobalt, or copper. In certain embodiments, M is aluminum. In other embodiments, M is chromium.

[0189] In certain embodiments, M has an oxidation state of +2. In certain embodiments, M is Zn(II), Cu(II), Mn(II), Co(II), Ru(II), Fe(II), Co(II), Rh(II), Ni(II), Pd(II) or Mg(II). In certain embodiments M is Zn(II). In certain embodiments M is Cu(II).

[0190] In certain embodiments, M has an oxidation state of +3. In certain embodiments, M is Al(III), Cr(III), Fe(III), Co(III), Ti(III) In(III), Ga(III) or Mn(III). In certain embodiments M is Al(III). In certain embodiments M is Cr(III).

[0191] In certain embodiments, M has an oxidation state of +4. In certain embodiments, M is Ti(IV) or Cr(IV).

[0192] In certain embodiments, M.sup.1 and M.sup.2 are each independently a metal atom selected from the periodic table groups 2-13, inclusive. In certain embodiments, M is a transition metal selected from the periodic table groups 4, 6, 11, 12 and 13. In certain embodiments, M is aluminum, chromium, titanium, indium, gallium, zinc cobalt, or copper. In certain embodiments, M is aluminum. In other embodiments, M is chromium. In certain embodiments, M.sup.1 and M.sup.2 are the same. In certain embodiments, M.sup.1 and M.sup.2 are the same metal, but have different oxidation states. In certain embodiments, M.sup.1 and M.sup.2 are different metals.

[0193] In certain embodiments, one or more of M.sup.1 and M.sup.2 has an oxidation state of +2. In certain embodiments, M.sup.1 is Zn(II), Cu(II), Mn(II), Co(II), Ru(II), Fe(II), Co(II), Rh(II), Ni(II), Pd(II) or Mg(II). In certain embodiments M.sup.1 is Zn(II). In certain embodiments M.sup.1 is Cu(II). In certain embodiments, M.sup.2 is Zn(II), Cu(II), Mn(II), Co(II), Ru(II), Fe(II), Co(II), Rh(II), Ni(II), Pd(II) or Mg(II). In certain embodiments M.sup.2 is Zn(II). In certain embodiments M.sup.2 is Cu(II).

[0194] In certain embodiments, one or more of M.sup.1 and M.sup.2 has an oxidation state of +3. In certain embodiments, M.sup.1 is Al(III), Cr(III), Fe(III), Co(III), Ti(III) In(III), Ga(III) or Mn(III). In certain embodiments M.sup.1 is Al(III). In certain embodiments M.sup.1 is Cr(III). In certain embodiments, M.sup.2 is Al(III), Cr(III), Fe(III), Co(III), Ti(III) In(III), Ga(III) or Mn(III). In certain embodiments M.sup.2 is Al(III). In certain embodiments M.sup.2 is Cr(III).

[0195] In certain embodiments, one or more of M.sup.1 and M.sup.2 has an oxidation state of +4. certain embodiments, M.sup.1 is Ti(IV) or Cr(IV). In certain embodiments, M.sup.2 is Ti(IV) or Cr(IV).

[0196] In certain embodiments, the metal-centered Lewis-acidic component of the carbonylation catalyst includes a dianionic tetradentate ligand. In certain embodiments, the dianionic tetradentate ligand is selected from the group consisting of: porphyrin derivatives; salen derivatives; dibenzotetramethyltetraaza[14]annulene (tmtaa) derivatives; phthalocyaninate derivatives; and derivatives of the Trost ligand.

[0197] In certain embodiments, the carbonylation catalyst includes a carbonyl cobaltate in combination with an aluminum porphyrin compound.

[0198] In certain embodiments, the carbonylation catalyst includes a carbonyl cobaltate in combination with a chromium porphyrin compound.

[0199] In certain embodiments, the carbonylation catalyst includes a carbonyl cobaltate in combination with a chromium salen compound. In certain embodiments, the carbonylation catalyst includes a carbonyl cobaltate in combination with a chromium salophen compound.

[0200] In certain embodiments, the carbonylation catalyst includes a carbonyl cobaltate in combination with an aluminum salen compound. In certain embodiments, the carbonylation catalyst includes a carbonyl cobaltate in combination with an aluminum salophen compound.

[0201] In certain embodiments, one or more neutral two electron donors coordinate to M M.sup.1 or M.sup.2 and fill the coordination valence of the metal atom. In certain embodiments, the neutral two electron donor is a solvent molecule. In certain embodiments, the neutral two electron donor is an ether. In certain embodiments, the neutral two electron donor is tetrahydrofuran, diethyl ether, acetonitrile, carbon disulfide, or pyridine. In certain embodiments, the neutral two electron donor is tetrahydrofuran . In certain embodiments, the neutral two electron donor is an epoxide. In certain embodiments, the neutral two electron donor is an ester or a lactone.

Solvents

[0202] In some embodiments, the carbonylation methods herein are performed in a solvent. In certain embodiments, the solvent is fed to the continuous carbonylation reactor in step (a) as a separate stream. In other embodiments, the solvent may be fed to the ractor along with the catalyst the epoxide or another feedstream entering the carbonylation reactor. In certain embodiments, the solvent enters the carbonylation reactor along with the carbonylation catalyst which is provided as a catalyst solution in the solvent. In certain embodiments, the solvent enters the carbonylation reactor in two or more separate feedstreams. In embodiments where solvent is present in the carbonylation reactor, it is also present in the carbonylation product stream.

[0203] The solvent may be selected from any solvent, and mixtures of solvents. Additionally, beta-lactone may be utilized as a co-solvent. Solvents most suitable for the methods include ethers, hydrocarbons and non protic polar solvents. Examples of suitable solvents include, but are not limited to: tetrahydrofuran (THF), sulfolane, N-methyl pyrrolidone, 1,3 dimethyl-2-imidazolidinone, diglyme, triglyme, tetraglyme, diethylene glycol dibutyl ether, isosorbide ethers, methyl tertbutyl ether, diethylether, diphenyl ether, 1,4-dioxane, ethylene carbonate, propylene carbonate, butylene carbonate, dibasic esters, diethyl ether, acetonitrile, ethyl acetate, dimethoxy ethane, acetone, and methylethyl ketone.

[0204] In some embodiments, the carbonylation methods further include a Lewis base additive in the carbonylation reactor. In certain embodiments such Lewis base additives can stabilize or reduce deactivation of the catalysts. In some embodiments, the Lewis base additive is selected from the group consisting of phosphines, amines, guanidines, amidines, and nitrogen-containing heterocycles. In some embodiments, the Lewis base additive is a hindered amine base. In some embodiments, the Lewis base additive is a 2,6-lutidine; imidazole, 1-methylimidazole, 4-dimethylaminopyridine, trihexylamine and triphenylphosphine.

Carbonylation Reaction Conditions

[0205] The carbonylation reaction conditions in step (a) of the methods above are preferably selected to effect efficient conversion of the epoxide to the desired product(s). Temperature, pressure, mixing, and reaction time influence reaction speed and efficiency. Additionally the ratio of reactants to each other and to the catalyst effect reaction speed and efficiency. The control and optimization of these parameters is a routine matter in the field of chemical engineering and the present invention places no particular constraints or limitations on the carbonylation reaction conditions.

[0206] In some embodiments, the reaction temperature can range from between about 20 C., to about 600 C. In some embodiments, the reaction temperature is about 20 C., about 0 C., about 20 C., about 40 C., about 60 C., about 80 C., about 100 C., about 200 C., about 300 C., about 400 C., about 500 C. or about , about 600 C. In some embodiments, the temperature is in a range between about 40 C. and about 120 C. In some embodiments, the temperature is in a range between about 60 C. and about 140 C. In some embodiments, the temperature is in a range between about 40 C. and about 80 C. In some embodiments, the temperature is in a range between about 50 C. and about 70 C. In some embodiments, the reactants, catalyst and solvent are supplied to the reactor at standard temperature, and then heated in the reactor. In some embodiments, the reactants are pre-heated before entering the reactor.

[0207] In some embodiments, the reaction pressure can range from between about 50 psig to about 5000 psig. In some embodiments, the reaction pressure is about 100 psig, about 200 psig, about 300 psig, about 400 psig, about 500 psig, about 600 psig, about 700 psig, about 800 psig, about 900 psig, or about 1000 psig. In some embodiments, the pressure ranges from about 50 psig to about 2000 psig. In some embodiments, the pressure ranges from about 100 psig to 1000 psig. In some embodiments, the pressure ranges from about 200 psig to about 800 psig. In some embodiments, the pressure ranges from about 800 psig to about 1600 psig. In some embodiments, the pressure ranges from about 1500 psig to about 3500 psig. In some embodiments, the pressure ranges from about 3000 psig to about 5500 psig. In some embodiments, the reaction pressure is supplied entirely by the carbon monoxide. For example, carbon monoxide is added to the at reactor at high pressure to increase pressure to the reaction pressure. In some embodiments, all reactants, solvent and catalyst are supplied to the reactor at reaction pressure.

[0208] In some embodiments, the ratio of catalyst to epoxide is selected, based on other reaction conditions, so that the reaction proceeds in an economical and time-feasible manner. In some embodiments, the ratio of catalyst to epoxide is about 1:10000 on a molar basis. In some embodiments, the molar ratio of catalyst to epoxide is about 1:5000, is about 1:2500, is about 1:2000, is about 1:1500, is about 1:1000, is about 1:750, is about 1:500, is about 1:250, is about 1:200, is about 1:150, or is about 1:100. In some embodiments, the concentration of the epoxide is in the range between about 0.1 M and about 5.0 M. In some embodiments, the concentration of the epoxide is in the range between about 0.5 M and about 3.0 M.

[0209] In some embodiments, the reaction is maintained for a period of time sufficient to allow complete, near complete reaction of the epoxide to carbonylation products or as complete as possible based on the reaction kinetics and or reaction conditions. In some mbodiments, the reaction time is a residence time in the carbonylation reactor in step (a). In certain embodiments, the residence time is about 12 hours, about 8 hours, about 6 hours, about 3 hours, about 2 hours or about 1 hour. In certain embodiments, the residence time is about 30 minutes, about 20 minutes, about 15 minutes, about 10 minutes, about 5 minutes, about 3 minutes, about 2 minutes, or about 1 minute. In certain embodiments, the residence time is less than 1 minute.

Carbonylation Reaction Products

[0210] The reaction product stream formed in step (a) of the methods herein may contain reaction by-products, un-reacted reactants, as well as catalyst and the desired carbonylation product. In some embodiments, the un-reacted reactants include epoxide or carbon monoxide. As such, the reaction may not proceed to completion and may be considered a partial reaction.

[0211] In some embodiments, where the product of the carbonylation is a beta lactone, an amount of un-reacted epoxide is maintained sufficient to prevent the formation of a succinic anhydride by further carbonylation of the beta lactone. Without being bound by a particular theory, it is speculated that the second reaction converting the beta-lactone to succinic anhydride does not proceed unless substantially all of the epoxide is consumed. Thus a remaining portion of the epoxide feed to the reactor that exits un-reacted appears to prevent the formation of succinic anhydride. Therefore, in some embodiments, the reaction product stream contains unconverted epoxide in an amount of at least about 5% epoxide, at least 3% epoxide, at least about 1% epoxide or at least about 0.1%, by weight.

Reaction Mode

[0212] The methods herein place no particular limits on the type, size or geometry of the reactor employed and indeed, in some cases, more than one reactor may be employed. It is to be understood that the term reactor as recited in the methods herein may actually represent more than one physical reactor (for example the reactor could be a train of continuous stirred tank reactors (CSTRs) connected in parallel or in series, or a plurality of plug flow reactors). In certain embodiments, the reactor referred to in the methods herein may also comprise more than one type of reactor (for example the reactor could comprise a CSTR in series with a plug flow reactor). Many such combinations are known in the art and could be employed by the skilled artisan to achieve an efficient reaction in step (a) of the methods described herein.

EXAMPLES

[0213] In a first example of a process according to the present invention, a continuous stirred tank reactor is fed with an ethylene oxide stream, a catalyst stream comprising a

[0214] THF solution of a carbonylation catalyst where the catalyst consists of the combination of chromium (III) salph complex and carbonyl cobaltate, and a carbon monoxide stream. The reactor is maintained at a temperature of 60 C. by heating, and maintained at 600 psig by feeding carbon monoxide on demand to a headspace within the reactor at that pressure. The reaction volume in the reactor is maintained at a constant level by withdrawing a reaction product stream from the reactor at a mass flow rate corresponding to the sum of the mass flows entering the reactor. The catalyst and EO feeds are maintained at a rate such that the chemical composition of the reactor contents are maintained at a steady state wherein the reaction mixture contains between 0.2 and 2 weight percent ethylene oxide, and between 20 and 60 weight percent beta propiolactone. The reaction product stream is directed first to a flash chamber maintained at a reduced pressure (e.g. between about 0.1 and 0.8 bar). Volatiles released from the reaction product stream in the flash chamber are recompressed and recycled. The reaction product stream is pumped from the flash chamber and flowed through a packed column containing beads of a sodium-form cation exchange resin. The resin exchanges sodium atoms for the cationic Lewis acid in the product stream to provide a first intermediate product stream substantially free of the cationic Lewis acid and containing sodium carbonyl cobaltate. The first intermediate product stream is fed to a second column containing the chloride form of an anion exchange resin to provide a second intermediate product stream containing THF, beta propiolactone and suspended sodium chloride. The second intermediate product stream is fed to a distillation unit where the THF and beta propiolactone are fractionated. The beta propiolactone is carried forward to another process while the THF is recycled. Solids primarily consisting of sodium chloride along with small amounts of polymerized products and catalyst residues are disposed of as waste.

[0215] The reactor is operated in this way for a first interval of 12 hours during which time the two ion exchange columns have accumulated catalyst residues and become substantially saturated with cationic Lewis acid and carbonyl cobaltate. At this time the saturated columns are removed from the reaction product pathway and replaced with fresh columns. The saturated exchange columns are treated with brine to elute the catalyst components which are extracted into a suitable organic solvent, recombined and purified to provide a new batch of carbonylation catalyst which is stored and fed to the reactor in a future time interval. Meanwhile, the eluted columns are processed to ready them for return to service in the process.

[0216] In a second example of a process according to the present invention, a continuous stirred tank reactor is fed with an ethylene oxide stream, a catalyst stream comprising a dioxane solution of tetraphenylporphyrinato aluminum carbonyl cobaltate, and a carbon monoxide stream. The reactor is maintained at a temperature of 60 C. by heating, and maintained at 600 psig by feeding carbon monoxide on demand to a headspace within the reactor at that pressure. The reaction volume in the reactor is maintained at a constant level by withdrawing a reaction product stream from the reactor at a flow rate corresponding to the sum of the flows entering the reactor. The catalyst and EO feeds are maintained at rates such that the chemical composition of the reactor contents are maintained at a steady state wherein the reaction mixture contains between 0.2 and 2 weight percent ethylene oxide, and between 20 and 60 weight percent beta propiolactone. The reaction product stream is maintained under 600 psig of CO pressure and directed through a resin column containing the chloride form of an anion exchange resin. The resin exchanges chloride atoms for the carbonyl cobaltate in the product stream to provide a first intermediate product stream substantially free of the cobalt carbonyl and containing tetraphenylporphyrinato aluminum chloride. A non-polar high boiling hydrocarbon is injected into the first intermediate product stream and the stream is pumped through a combined static mixer and heat exchanger such that it is cooled to a sub-ambient temperature and the tetraphenylporphyrinato aluminum chloride precipitates. This stream is fed through a filter unit to accumulate the solids while the filtrate from this unit is directed to a distillation unit where the dioxane and betapropiolactone are separated. The isolated beta propiolactone is carried forward to another process while the dioxane is recycled. The heavies from the distillation unit consisting primarily of the high boiling hydrocarbon are cooled and recycled.

[0217] The reactor is operated in this way for a first interval of 12 hours during which time the anion exchange column accumulates carbonyl cobaltate until it is substantially saturated. At this time the saturated column is removed from the reaction product pathway and replaced with a fresh anion exchange column. The saturated exchange column is treated with brine to elute sodium carbonyl cobaltate which is purified and used to generate new carbonylation catalyst by combining it with chloride salt of the Lewis acid recovered from the filtration unit. The resulting batch of carbonylation catalyst is stored and fed to the reactor during a future time interval. Meanwhile, the eluted anion exchange column is processed to ready it for return to service in the process during a future interval.

[0218] It is to be understood that the embodiments of the invention herein described are merely illustrative of the application of the principles of the invention. Reference herein to details of the illustrated embodiments is not intended to limit the scope of the claims, which themselves recite those features regarded as essential to the invention.