Process for the production of pentamethylene-1,5-diamine

Abstract

A process for the synthesis of pentane-1,5-diamine from L-lysine is provided by thermal decarboxylation in the presence of an inert solid to form a carbamate precipitate from decarboxylation of L-lysine and using carbon dioxide released from L-lysine.

Description

[0001] Invention Field This invention relates to a method for producing 1,5-pentamethylenediamine (PMDA) (commonly known as cadaverine) from L-lysine via a thermal decarboxylation process. Background of the Invention Polyamides (PAs) are well-known polymers with significant applications in the automotive, sportswear, and lifestyle apparel industries. Diamines are a crucial raw material monomer component used in the production of such polyamides. Currently, 6.6 million tons of petroleum-based polyamides are produced globally annually, with the synthetic petrochemical product hexane-1,6-diamine or hexamethylenediamine (HMDA) primarily used as the monomer.

[0003] However, petrochemically based polyamides are known to contribute to the greenhouse effect, leading to serious environmental problems. Therefore, research on bio-based polyamides has progressed at a faster pace. Cadaverine, also known as 1,5-pentamethylenediamine (PMDA), is a five-carbon organic linear aliphatic diamine and a homologue of putrescine. First discovered in decaying carcasses, cadaverine is primarily formed during the putrefaction of animal tissues, and particularly through bacterial decarboxylation of lysine, i.e., during protein hydrolysis. Besides being a naturally occurring polyamine, PMDA fortunately provides excellent properties for polyamides prepared from it, such as high tensile strength, high melting point, and resistance to organic solvents, as well as reduced water absorption and excellent dimensional stability. Therefore, PMDA has attracted considerable interest as a potential bio-based alternative to the dominant hexamethylenediamine monomer for the production of desirable biopolyamides with reduced greenhouse gas impacts and beneficial properties and performance characteristics in a variety of application environments.

[0004] Conventional known methods for PMDA production include catalytic decarboxylation of α-amino acids and biosynthetic methods, such as de novo biosynthesis from various carbon sources. However, known methods for catalytic decarboxylation of α-amino acids are characterized by low yields and prohibitive costs, and there is generally an unmet need for a commercially viable and economical method for producing PMDA products of acceptable monomeric purity. Ideally, such a method would utilize the carbon dioxide released during the decarboxylation of α-amino acids such as L-lysine to reduce energy consumption and the carbon footprint associated with the production of PMDA and PMDA-based polyamides. Invention Overview This section provides a general overview of the invention, rather than a full disclosure of the entire scope of all features of the invention.

[0006] In view of the unmet needs mentioned above, the present invention provides a PMDA production method that, in one aspect, improves the decarboxylation yield and the quality of PMDA produced from L-lysine. In another aspect, the present invention provides a PMDA production method via decarboxylation of L-lysine that utilizes the carbon dioxide released through decarboxylation, which would otherwise constitute waste or require the input of other resources to be effectively utilized in some way.

[0007] Another object of the present invention is to provide a PMDA production method that offers sustainable economic benefits. Yet another object of the present invention is to provide a PMDA production method that allows for the easy separation of the final product from the reaction mixture.

[0008] More specifically, the method of the present invention relates to thermal decarboxylation of L-lysine at elevated temperatures in a reaction vessel containing an inert solid and a nonpolar solvent or solvent mixture (and L-lysine) to provide a decarboxylation product mixture containing a pentane-1,5-diamine carbamate precipitate.

[0009] The decarboxylation product mixture is then filtered to obtain a residue containing an inert solid and a pentane-1,5-diamine carbamate precipitate. The residue is then combined with a nonpolar solvent or solvent mixture under heating to both release CO2 from the pentane-1,5-diamine carbamate and provide a solution of the pentane-1,5-diamine mixed with the inert solid in the solvent or solvent mixture (thus providing a filterable mixture, wherein the inert solid is preferably retained substantially alone in solid form), wherein PMDA is readily soluble in the nonpolar solvent or solvent mixture but is also readily separable from the nonpolar solvent or solvent mixture.

[0010] The solution mixture is then filtered in a second filtration step to remove inert solids and provide a filtrate containing pentane-1,5-diamine dissolved in the solvent or solvent mixture. The resulting filtrate is then subjected to a separation step to separate the pentane-1,5-diamine from the solvent or solvent mixture.

[0011] In some implementations, L-lysine is derived from plant feed, obtained via fermentation broth from the fermentation of dextrose.

[0012] In some embodiments, the nonpolar solvent or solvent mixture used to form the PMDA carbamate precipitate contains an aldehyde or ketone, such as methyl ethyl ketone or methyl isobutyl ketone.

[0013] In some embodiments, the nonpolar solvent or solvent mixture used to form a PMDA solution and release carbon dioxide from PMDA carbamate may contain a nonpolar solvent and water, such as an alcohol and water.

[0014] In some embodiments, the method includes the step of washing at least a portion of the inert solid with water before recycling at least a portion of the inert solid back to the reaction vessel for reuse in the method.

[0015] In some embodiments, the method includes adding CO2 to the reactor after applying heat to induce thermal decarboxylation of L-lysine to achieve a higher yield of PMDA as a precipitate in the product mixture.

[0016] In some embodiments, the inert solid may be selected from the group consisting of: alumina, silicon dioxide, sand, glass beads, and silicon carbide, wherein glass beads are preferred.

[0017] In some embodiments, the method for separating PMDA from a nonpolar solvent or solvent mixture includes a distillation step.

[0018] In some embodiments, at least the initial steps for producing PMDA carbamate can be carried out under a nitrogen or nitrogen-rich atmosphere to remove air from the headspace of the reactor.

[0019] In some embodiments, at least the initial steps for producing PMDA carbamate are carried out in a nitrogen or nitrogen-rich atmosphere at a temperature not exceeding 175 degrees Celsius for a span of not more than 2 hours.

[0020] In some implementations, at least a portion of the inert solids after the second filtration step is washed with water, dried, and then recycled back to the reactor to eliminate waste.

[0021] In other embodiments, the salt washed from at least a portion of the inert solids after the second filtration step is recycled to the fermentation step for the production of additional L-lysine from dextrose.

[0022] To further understand the invention in each aspect and the various embodiments just outlined, reference may be made to the following detailed description, items, embodiments, and claims, as well as the accompanying drawings, which together describe the invention as more particularly claimed below. Brief description of the attached diagram A better understanding of the features and advantages of the invention will be obtained by referring to the following detailed description and accompanying drawings, which illustrate illustrative embodiments utilizing the principles of the invention, in which: Figure 1 The schematic diagram illustrates, in one embodiment, the method of the present invention relating to the fermentation of dextran to produce L-lysine feedstock.

[0024] Figure 2 The figure illustrates the proposed non-limiting reaction mechanism / reaction pathway for the formation of PMDA from L-lysine in accordance with the present invention.

[0025] Figure 3 The phases observed in the conversion of L-lysine to PMDA carbamate in CSTRs, in the presence of an inert solid in the form of glass beads, and in a nonpolar solvent medium (such as MEK) are depicted.

[0026] Figure 4 The figure illustrates a short-path distillation process for recovering desired PMDA products. Invention Details The embodiments described herein, along with their various features and advantageous details, are explained more fully with reference to the non-limiting embodiments shown in the accompanying drawings and the following description.

[0028] Now go to Figure 1 The diagram schematically illustrates a process embodiment 10 of the present invention, which begins with clarified and dehydrated but otherwise unrefined L-lysine feedstock 12, which has been produced by fermentation (14) of dextrose, such as currently known and commercially available dextrose, for example, to provide crude L-lysine fermentation broth (16), which is then filtered (18) to remove biomass and then dehydrated (20) to provide the L-lysine feedstock 12 mentioned above. Preferably, sufficient water is removed to provide L-lysine feedstock 12 containing about 20% or less water.

[0029] L-lysine raw material 12 is preferably dried solid (see...). Figure 3 The inert solid 24, supplied together with the lysine in the nonpolar solvent or solvent mixture 26 (also added to reactor 22), serves to provide a wettable surface on which lysine dissolved in the nonpolar solvent or solvent mixture 26 can be deposited and heated to release carbon dioxide. On this wettable surface, the PMDA carbamate product can then be formed, at least partially, by the released carbon dioxide and by supplemental carbon dioxide (not shown) optionally but preferably supplied to reactor 22, to promote a higher yield of the lysine feedstock 12 from the PMDA carbamate, all according to... Figure 2 The hypothetical, non-limiting reaction pathway is shown. The decarboxylation reaction and subsequent formation of PMDA carbamate are preferably carried out in a nitrogen-rich atmosphere or generally under a nitrogen blanket, as shown by the nitrogen feed stream 28 entering reactor 22.

[0030] The contents 30 of reactor 22 after lysine feedstock 12 is converted into PMDA carbamate are then filtered in a first filtration step 32 to provide a residue containing inert solids and preferably substantially all of the PMDA carbamate, as well as a filtrate containing a nonpolar solvent or solvent mixture, which can be recycled back to reactor 22 in stream 34.

[0031] The residue portion 36 is combined with a nonpolar solvent or solvent mixture 38 under heating conditions to both release CO2 (top CO2 stream not shown) from the pentane-1,5-diamine (PMDA) carbamate in the residue 36 and provide a solution of pentane-1,5-diamine mixed with the inert solid in the residue 36 in the solvent or solvent mixture, wherein PMDA is readily soluble in the nonpolar solvent or solvent mixture 38 but is also readily separable from the nonpolar solvent or solvent mixture 38.

[0032] This mixture of inert solids and PMDA solution is then provided as stream 40 to a second filtration step 42, where the inert solids are recovered in stream 44 for recycling to reactor 22 after a water washing step 46 to remove residual salt 48 from the initial fermentation broth 16. These residual salts can be recycled back to dextrose fermentation 14, while the washed inert solids can be returned to reactor 22 via stream 50 (as a supply of inert solids 24).

[0033] The filtrate 52 from the second filtration step 42 (containing the desired PMDA product in a solution having a nonpolar solvent or solvent mixture supplied in stream 38) is then sent to a separation step 54 – preferably involving, as described above, separation step 54. Figure 4 The short-path distillation shown is a simple distillation method for recovering PMDA product 56, which preferably already has monomer-grade purity but can be further refined and purified as needed using one or more well-known methods. The nonpolar solvent or solvent mixture from which PMDA has been separated can be recycled and includes a solvent or solvent mixture 38 for washing the residue 36 from the first filtration step 32.

[0034] The suitable inert solid 24 is preferably easily filterable, effectively transferring heat for the thermal decarboxylation of lysine feedstock 12 and the release of carbon dioxide from PMDA carbonate prior to the second filtration step 42, and providing a clean, smooth surface that is readily wetted by lysine in solution to form PMDA carbonate in reactor 22. Exemplary inert solids will be selected from the group consisting of alumina, silica, sand, glass beads, and silicon carbide, with glass beads being preferred.

[0035] The nonpolar solvent or solvent mixture 26 used in reactor 22 is preferably selected from aldehydes and ketones, such as methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone or acetone, wherein methyl ethyl ketone is an example, and the nonpolar solvent or solvent mixture 38 recovered from the second filtration step 42 as stream 52 for forming the PMDA solution preferably contains alcohol or alcohol / water mixture, such as ethanol or ethanol and water.

[0036] In reactor 22, a temperature ranging from about 150 degrees Celsius to preferably not exceeding about 200 degrees Celsius will be used, and this temperature will be maintained for about 2 hours and preferably not exceeding about 5 hours while being stirred.

[0037] Example Example 1 - PMDA Synthesis Using CO2 and Inert Solids 25 g of Sigma Aldrich lysine (>98% purity), 90 g of glass beads (with diameters ranging from 150 μm to 212 μm), and 500 mL of methyl ethyl ketone were loaded into a 1 L Pal reactor. The reactor was purged three times with nitrogen to remove air from the headspace. After purging, the reactor was pressurized with 200 psi nitrogen and heated to 180 °C with stirring at 940 RPM, and the temperature was maintained for 2 hours. Heating was then stopped, and the reactor was cooled to room temperature. During cooling, when the temperature dropped to approximately 100 °C, some nitrogen pressure was released, and an additional 200 psi of carbon dioxide was supplied to the reactor. The resulting PMDA carbamate solids were then filtered from the mixture and passed through… 1 H NMR, 13 Analysis was performed using C NMR and UPLC. The MEK organic layer was washed from the solid glass beads by decantation and then analyzed by UPLC. To convert the PMDA carbamate solid to PMDA, the solid was first dissolved in an ethanol / water mixture and heated, and then purified by short-path distillation. 1 H NMR, 13 The generated PMDA was analyzed by C NMR and UPLC, with a PMDA yield of 82% (94% of which was recovered by distillation using ethanol / water).

[0038] Example 2 In a 300 mL Hastelloy Pal reactor, 4.1 g of 35-60 mesh silica gel, 5.3 g of lysine (Aldrich), and 1.3 g of isophorone were added to 57.2 g of methyl ethyl ketone. The reactor containing the contents was then purged three times with nitrogen and pressurized to 200 psig with nitrogen. After maintaining the reactant mixture at 160°C for 1 hour with continuous stirring at 650 rpm, carbon dioxide was added to reach a combined pressure of 450 psig, and the reaction was allowed to continue for an additional 0.5 hours. The system was then cooled to ambient / room temperature, and the reactor contents were treated in the same manner as in Example 1, with a PMDA yield of 75%.

[0039] Comparative Example 1. PMDA Synthesis without CO2 and Inert Solids In a 300 mL Hastelloy Pal reactor, 5.3 g of lysine (20-40 mesh, from a lysine plant) and 1.3 g of isophorone were added to 56.1 g of methyl ethyl ketone (MEK). The system was purged three times with nitrogen, and then nitrogen was added to a final concentration of 200 psig. The reaction mixture was heated to 170 °C and maintained at that temperature for 1.5 hours with stirring at 650 rpm. The reactor was then cooled to ambient / room temperature, yielding a product mixture comprising a viscous substance. Analysis of this substance indicated the presence of PMDA, produced in a yield of 54%.

Claims

1. A method for producing pentane-1,5-diamine from L-lysine, comprising: a. Prepare a reaction mixture at an elevated temperature, the reaction mixture comprising L-lysine or an L-lysine salt, an inert solid, and a nonpolar aldehyde or ketone solvent; b. The reaction mixture is maintained at the elevated temperature for a period of time sufficient to cause at least some decarboxylation of the L-lysine and form a product mixture comprising pentane-1,5-diamine carbamate precipitate and pentane-1,5-diamine; c. Filter the product mixture to provide a residue comprising the inert solid and pentane-1,5-diamine carbamate precipitate; d. Heating the residue together with a solvent or solvent mixture to obtain a solution mixture thereby releasing carbon dioxide, the solution mixture comprising pentane-1,5-diamine dissolved in the solvent or solvent mixture and dispersed inert solids.

2. The method of claim 1, wherein the solution mixture from step d is filtered to remove the inert solid, leaving a filtrate containing pentane-1,5-diamine dissolved in the solvent or solvent mixture.

3. The method of claim 2, wherein the pentane-1,5-diamine is filtered from the solvent or solvent mixture in the filtrate.

4. The method according to claim 1, wherein one or more L-lysine salts are produced from the fermentation broth of dextrose fermentation.

5. The method according to claims 1-4, wherein at least a portion of the filtrate containing the nonpolar aldehyde or ketone solvent obtained from step c is recycled back to the reaction vessel.

6. The method of claim 2, wherein at least a portion of the filtered inert solids is recycled back to the reaction vessel.

7. The method according to claims 2 and 6, wherein at least a portion of the inert solid is washed with water before being recycled back to the reaction vessel.

8. The method of claim 7, wherein the salt washed from the at least portion of the inert solid is recycled for dextrose fermentation to produce L-lysine.

9. The method according to any one of claims 1-8, wherein the solvent or solvent mixture comprises an alcohol.

10. The method of claim 9, wherein the solvent or solvent mixture is selected from ethanol or methanol.

11. The method of claim 10, wherein the solvent or solvent mixture comprises ethanol or a combination of ethanol and water.

12. The method of claim 3, further comprising the step of distilling the filtrate.

13. The method of claim 12, wherein at least a portion of the solvent or solvent mixture obtained from step d is recycled for combination with the permeate under heating.

14. The method according to any one of claims 1-13, wherein the decarboxylation in step b is carried out for 2 hours at a temperature of up to 175 degrees Celsius under a nitrogen or nitrogen-rich atmosphere.

15. The method according to any one of claims 1-14, wherein the inert solid is selected from the group consisting of: alumina, sand, silicon dioxide, glass beads and silicon carbide.

16. The method of claim 15, wherein the inert solid is a glass bead.

17. The method according to any one of claims 1-16, wherein the nonpolar aldehyde or ketone solvent is methyl ethyl ketone or methyl isobutyl ketone.

18. The method of claim 17, wherein the nonpolar aldehyde or ketone solvent is methyl ethyl ketone.

19. The method according to any one of claims 1-18, further comprising the step of adding carbon dioxide to the reaction vessel after heating the reaction mixture to the elevated temperature to form pentane-1,5-diamine carbamate.

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