BRASSELET HUGO LUC YVON (NL)
KORTLEVER RUUD (NL)
NIJENHUIS JOHN (NL)
| EP3885469A1 | 2021-09-29 |
BUREK ET AL., GREEN CHEM., vol. 21, 2019, pages 3232 - 3249
NISHIMI ET AL., EUR. J. ORG. CHEM., 2011, pages 4113 - 4120
CAMPOS-MARTIN, ANGEW. CHEM. INT. ED., vol. 45, 2006, pages 6962 - 6984
RAUCH ET AL., GREEN CHEMISTRY, vol. 19, no. 2, 2017, pages 376 - 379
HOU ET AL., ANGEW. CHEM. INT, vol. 59, 2020, pages 17356 - 17376
ZHANG ET AL., ACS CATALYSIS, vol. 10, no. 23, 2020, pages 14195 - 14200
| Claims 1. Process for the production of organic compounds with at least one oxygen atom in their structure, which process comprises the steps of: - feeding a first stream comprising CO2 to an electrochemical cell; - contacting at least part of said CO2 with a cathode, thereby converting at least part of said CO2 into an intermediate compound; - feeding a second stream comprising water to said electrochemical cell; - providing hydrogen peroxide (H2O2); - oxidizing at least part of said intermediate compound by contacting it with at least part of said hydrogen peroxide in the presence of an enzyme, thereby producing said organic compound. 2. Process according to claim 1, wherein said H2O2 is produced in situ by at least one of the following: - electrochemical reaction; - enzymatic reaction; - photochemical reaction; and - from nuclear waste. 3. Process according to claim 2, wherein said hydrogen peroxide is provided by contacting at least part of said water with an anode, thereby converting at least part of said water into hydrogen peroxide. 4. Process according to any of the previous claims, wherein H2O2 is produced in the same cell as wherein the CO2 is converted into the intermediate compound. 5. Process according to claim 4, wherein H2O2 is made via anodic water oxidation. 6. A process of claim 5, wherein the H2O2 is made by combining the cathodic reduction of CO2 and the cathodic reduction O2. 7. Process according to any of the previous claims, wherein said intermediate compound is selected from the group consisting of alkenes, alkanes, alcohols, aldehydes and combinations thereof. 8. Process according to any of the previous claims wherein the step of oxidizing at least part of said intermediate compound comprises an oxidation reaction selected from: - epoxidation (production of epoxides), such as ethylene oxide; - hydroxylation; - Baeyer-Villiger oxidation (forming an ester from a ketone or an aldehyde); and - combinations thereof. 9. Process according to any of the previous claims, which is a continuous process. |
BACKGROUND OF THE INVENTION
The invention is in the field of chemical synthesis, in particular the synthesis of organic compounds using CO 2 as a starting material and using renewable energy sources.
The electrochemical reduction of carbon dioxide to more reduced chemical species using electrical energy is known per se.
An object of the present invention is to provide an energy efficient process for producing valuable organic chemicals, employing the electrochemical reduction of carbon dioxide.
A further object is to produce these organic compounds with a high selectivity and conversion.
Organic compounds with high commercial value are for instance oxidized compounds, such as epoxides and alcohols and products derived thereof. Converting the intermediate compounds obtained from electrochemical reduction of carbon dioxide into these oxidized compounds requires an oxidizing agent.
The present inventors found that a very efficient and selective process is obtained when hydrogen peroxide is produced in the same electrochemical cell as used for the electrochemical reduction of carbon dioxide, and this hydrogen peroxide is used for the oxidation of the intermediate compounds. In accordance with the invention, hydrogen peroxide can be produced in both the cathode compartment: via O 2 reduction, as well as in the anodic compartment via H 2 O oxidation. The process of the invention is in particular very beneficial if the oxidation with hydrogen peroxide is carried out in the presence of an enzyme.
Thus the present invention provides a CO 2 -neutral, or even “CO 2 - negative” (viz. resulting in a net removal of CO 2 from the atmosphere), oxidation process. Also, a highly selective conversion under mild reaction conditions are obtained. The present invention allows for a modular approach, which is suitable for the production of a broad range of base chemicals.
BRIEF SUMMARY OF THE INVENTION
In accordance with the present invention there is provided a process for the production of organic compounds with at least one oxygen atom in their structure, which process comprises the steps of:
- feeding a first stream comprising CO 2 to an electrochemical cell;
- contacting at least part of said CO 2 with a cathode, thereby converting at least part of said CO 2 into an intermediate compound ;
- feeding a second stream comprising water to said electrochemical cell;
- providing hydrogen peroxide (H 2 O 2 ), for instance by contacting at least part of said water with an anode, thereby converting at least part of said water into hydrogen peroxide;
- oxidizing at least part of said intermediate compound by contacting it with at least part of said hydrogen peroxide in the presence of an enzyme, thereby producing said organic compound.
Thus the invention provides a process for the electroenzymatic synthesis of chemicals starting from carbon dioxide, so that CO 2 can be used as a starting material for organic synthesis of oxygen containing compounds.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is a schematic representation of a process in accordance with the present invention. Figure 2 is a schematic representation of the process of the present invention wherein H 2 O 2 is produced in situ using an electrochemical cell.
Figure 3 is a further schematic representation of the process of the present invention wherein H 2 O 2 is produced in situ using an electrochemical cell.
DETAILED DESCRIPTION OF THE INVENTION
According to the invention there is provided a process for the production of organic compounds containing oxygen, such as epoxides, alcohols and products derived from those such as diols, a-substituted alcohols, aldehydes, carboxylic acid derivates (such as acids, esters, amides, nitriles) etc..
Suitable oxidation reactions that can be carried out in accordance with the invention are:
- epoxidation (production of epoxides), such as ethylene oxide, propylene oxide, or higher homologues:
- hydroxylation:
- allylic hydroxylation:
- Baeyer-Villiger oxidation (forming an ester from a ketone or an aldehyde);
Reactions such as hydroxylation and epoxidation can be stereoselective in accordance with the invention.
In accordance with the invention, hydrogen peroxide can be produced in both the cathode compartment: via O 2 reduction, as well as in the anodic compartment via H 2 O oxidation.
The electrochemical cell to which the CO 2 comprising feed stream is fed can be for instance of the H-cell type, comprising gas diffusion electrode based flow cells and membrane electrode assembly cells.
The cathode which is used to allow contact with CO 2 so that it may be reduced can be made of a support material, for instance a carbon- based gas diffusion layer, on which a metal-based electrocatalyst, such as copper, is deposited.
The intermediate compound that is formed is preferably selected from the group consisting of alkenes, alkanes, alcohols, aldehydes, ketones, and combinations thereof.
The anode which is used to oxidize water can be made from a support material on which a carbon-based, for instance boron doped diamond (BDD), or metal-based, for instance manganese oxide, is deposited. As enzyme, any polypeptide capable of activating hydrogen peroxide can be used. Possible embodiments comprise: Peroxidases/peroxygenases from the E.C. classes 1.11.1 and 1.11.2; Monooxygenases from E.C. 1.14.11, 1.14.12. or 1.14.13 or hydrolases able to accept H 2 O 2 as nucleophile.
Suitable peroxidases/peroxygenases capable of catalyzing H 2 O 2 - dependent oxidation reactions. Peroxidases (E.C. 1.11) comprise all H 2 O 2 - active enzymes that oxidize organic or inorganic compounds. Representative examples comprise NADH peroxidase, chloride peroxidase, ascorbate peroxidase, phospholipid-hydroperoxide glutathione peroxidase, manganese peroxidase, lignin peroxidase, versatile peroxidase, glutathione amide- dependent peroxidase, bromide peroxidase, dye decolorizing peroxidase, hydroperoxy fatty acid reductase, (S)-2-hydroxypropylphosphonic acid epoxidase, thioredoxin-dependent per oxiredoxin, glutaredoxin-dependent per oxiredoxin, glutathione-dependent peroxiredoxin, glutathione-dependent per oxiredoxin, prostamide/prostaglandin F2alpha synthase, unspecific peroxygenase (EC 1.11.2.1, including aromatic peroxygenase, mushroom peroxygenase, haloperoxidase-peroxygenase, Agrocybe aegerita peroxidase) is an enzyme with systematic name substrate:hydrogen peroxide oxidoreductase (RH -hydroxylating or -epoxidising). This enzyme catalyzes RH + H 2 O 2 ROH + H 2 O), myeloperoxidase, plant seed peroxygenase (EC 1.11.2.3, also referred to as plant peroxygenase, soybean peroxygenase) is an enzyme with systematic name substrate:hydroperoxide oxidoreductase (RH- hydroxylating or epoxidizing). This enzyme catalyzes RIH + R2OOH R1OH + R2OH), fatty-acid peroxygenase (EC 1.11.2.4, fatty acid hydroxylase, P450 peroxygenase, CYP152A1, P450BS, P450SPalpha) is an enzyme with systematic name fatty acid:hydroperoxide oxidoreductase (RH- hydroxylating). This enzyme catalyzes fatty acid + H 2 O 2 3- or 2-hydroxy fatty acid + H 2 O), and combinations thereof.
Suitable monooxygenases comprise one or more enzymes capable of incorporating one atom of oxygen from O 2 if contacted with a suitable reductant. In the present invention the capability of these enzymes to circumvent 02/reductant by directly utilizing H 2 O 2 (H 2 O 2 shunt pathway). This comprises enzymes containing heme- or non-heme-iron monooxygenases, Cu-dependent monooxygenases and also flavin-dependent monooxygenases.
Suitable hydrolases comprise one or more enzymes from the E.C. class 3 that next to water as nucleophile can also react with H 2 O 2 such as hydrolases acting on ester-, amide, ether-, glycoside bonds.
Hydrogen peroxide can be supplied to the enzymatic reaction in various ways, as described e.g. by Burek et al. (Green Chem., 21(2019)3232- 3249, DOI 10.1039/C9GC00633H). A particular advantage of the current invention is that the electrochemical equipment and current applied can be used not only for the reduction of CO 2 but also for the in situ generation of H 2 O 2 . In this way, many shortcomings of the methods of the state-of-the-art can be elegantly solved. For example, anodic water oxidation to generate H 2 O 2 produces no by-product, which would impede the reaction and/or the product isolation. The combined electrochemical H 2 O 2 generation (either anodically or cathodically) also allows to dose the rate at which H 2 O 2 is generated and thereby minimises enzyme inactivation. This methods also avoids dilution effects as observed by external addition of H 2 O 2 (from aqueous stock solutions).
In accordance with the present invention H 2 O 2 can be provided by using known techniques. It can be added as such, or it may be produced in situ, for instance by - electrochemical reaction (by anode oxidation or cathode reduction). Examples of these reactions are shown in figures 2 and 3, respectively. Advantageously the electrochemical H 2 O 2 production is carried out in the same electrochemical cell where the CO 2 is converted into the intermediate compound, preferably the H 2 O 2 is produced via anodic water oxidation (figure 2), or via cathodic oxygen reduction, wherein the oxygen is obtained by anodic water oxidation (figure 3). - by enzymatic reaction (typically involving an amino acid sequence), in particular by one or more enzymes from the EC number family, such as glucose dehydrogenase, sulfhydryl oxidase, formate dehydrogenase, or combinations thereof. Specific examples of suitable enzymes for this purpose are oxidoreductases of the class E.C. 1, more specifically enzymes from the classes E.C. 1.9 (heme monooxygenases) and E. C. 1.11. (peroxidases), hydrolases (E.C. 3.), and combinations thereof;
- by organometallic syntheses as the well-known industrial anthraquinone process (see e.g. Nishimi et al. Eur. J. Org. Chem. 2011, 4113-4120, DOI: 10.1002/ejoc.201100300) and/or other method already reviewed (see e.g. Campos-Martin et. al. Angew. Chem. Int. Ed. 2006, 45, 6962 - 6984 DOI: 10.1002/anie.200503779)
- by photochemical reactions using the flavonoid moiety (see e.g. Rauch et al. Green chemistry, 2017, 19(2), 376-379 DOI: 10.1039/c6gc02008a) or all others methods known by the skilled in the art and, for example, recently reviewed (see e.g. Hou et al. Angew. Chem. Int. Ed. 2020, 59, 17356-17376, doi.org/10.1002/anie.201911609); and/or
- from nuclear waste (see e.g. Zhang et al. ACS Catalysis 10(23)(2020) 14195- 14200, https://doi.org/10.102 l/acscatal.0c03059).
The above-mentioned enzyme catalysts can be used for instance in aqueous media comprising ionic strengths of typically between 1 mM and 5 M of salt (inorganic or organic) preferably between 1 M and 3 M, pH values ranging between pH 2 and pH 13, preferably between 4 and 10, more preferably 6-8, typically around 7. Suitable reaction temperatures range between -20 °C and 140 °C, preferably from 5-80 °C, more preferably from 15-35 °C, in particular around room temperature (25 °C).
Next to aqueous media, also mixtures with water-soluble and water-insoluble solvents can be used. The ratio of the solvents can range between 1:99 to 99:1.
Also non-aqueous media such as ionic liquids or deep eutectic solvents can be used. The biocatalyst can be homogeneously dissolved in the reaction mixture or can be confined to a solid support, or it can for instance be confined within a microbial cell immobilized to a heterogeneous support, including the electrodes. A typical apparatus for carrying out the invention comprises the following elements: a cathode and anode electrode, separated by a membrane or separator, a water containing anolyte which is flowed through the apparatus.
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