Process for producing carbon monoxide and process for producing a synthetic fuel

Abstract

The invention relates to a process for producing carbon monoxide by decarbonylation of a compound A, B or C, wherein the compound A has the structural formula: R5-C6 (R 1-4 ) - [N (CHO) - C6 (R 1-4 ')] n - R5', compound B has the structural formula: R5 - [C6 (R 1-4 ) - N (CHO) - C6 (R 1-4 ')] n - R5', and compound C has the structural formula: R5 - [C6(R 1-4 ) - N(CHO) - C6 (R1-4') - X] n - R5', where R1, R2, R3, R4, R1', R2', R3', and R4' are independently H, D, F, an alkyl radical, or an aryl radical, where X is an aliphatic bridge, an aromatic bridge, an ether group, an ester group, an amide group, or a urethane group, where n is in a range from 1 to 100,000. Furthermore, the invention relates to a process for producing a synthetic fuel in which the carbon monoxide is reduced using hydrogen.

Description

[0001] The invention relates to a process for producing carbon monoxide and a process for producing a synthetic fuel using the carbon monoxide.

[0002] Carbon monoxide and hydrogen are used in the production of renewable synthetic fuels, such as hydrocarbons or methanol. The hydrogen is produced by electrolysis of water. The carbon monoxide can be produced, for example, by a reverse water gas shift reaction (rWGS): CO2 + H2 ↔ CO + H2O. However, to produce carbon monoxide in this reaction with a good yield, a temperature of over 800°C is required, and the water must be removed, which is a complex process. As an alternative to the water gas shift reaction, carbon monoxide can be released from an amide, such as formamide. Formamide can be produced, for example, by first reacting ammonia with carbon dioxide and water to form bicarbonate: NH3 + CO2 + H2O → [NH4 + ] [HCO3 - ] (1) and then the bicarbonate is hydrogenated to a formate: [NH4 + ] [HCO3 - ] + H2 → [NH4 + ] [HCO2 - ] + H2O. (2)

[0003] The formate can dehydrate to formamide: [NH4 + ] [HCO2 - ] → HCONH2 + H2O. (3)

[0004] Carbon monoxide can be released from the formamide: HCONH2 → NH3 + CO, (4) The ammonia is regenerated. Reactions (1) to (4) together represent the reverse water gas shift reaction CO2 + H2 → CO + H2O.

[0005] Another alternative to the water gas shift reaction is the first step of producing formic acid from carbon dioxide and hydrogen: CO2 + H2 → HCOOH. (5)

[0006] Subsequently, the reaction of ammonia with formic acid leads to the formation of formamide: HCOOH + NH3 → HCONH2 + H2O, (6) Here, too, carbon monoxide is released according to (4). The disadvantage of reaction (4) is that hydrogen cyanide and polymers are formed as undesirable byproducts.

[0007] Formic acid can also be decomposed directly on acidic catalysts by the reaction HCOOH → CO + H2O.

[0008] The object of the invention is therefore to create a process which enables the release of carbon monoxide with a high yield.

[0009] The process according to the invention for producing carbon monoxide is carried out by decarbonylating a compound A, B or C, where compound A has the structural formula:, compound B has the structural formula:, and compound C has the structural formula: where R1, R2, R3, R4, R1', R2', R3' and R4' are independently H, D, F, an alkyl radical or an aryl radical, where X is an aliphatic bridge, an aromatic bridge, has an ether group, has an ester group, has an amide group or has a urethane group, where n is in a range from 1 to 100,000. Surprisingly, it has been found that with formamides of the compounds A, B and C, the decarbonylation takes place in high yield. The compounds A, B and C thus function as a storage medium for carbon monoxide. In case X has the alkyl radical or the aryl radical, the solubility of compound C in nonpolar solvents can be increased.In the case where X contains an ether group, an ester group, an amide group, or a urethane group, the solubility of compound C in polar solvents can be increased. Decarbonylation occurs analogously to reaction (4) to form an amine.

[0010] Preferably, n=1. Alternatively, n>1 is preferred, with n=2 being particularly preferred. For example, n can be in a range from 1 to 100 or 1 to 20, or greater than 100. The larger n, the greater the ratio of the number of atoms of the amide groups to the number of atoms of the remaining atoms in compounds A, B, or C. This allows more mass of carbon monoxide to be stored per unit mass of amide.

[0011] The alkyl radical for R1, R2, R3, R4, R1', R2', R3', and R4' is preferably unbranched or branched. The unbranched alkyl radical preferably has 1 to 5 carbon atoms. For example, the unbranched alkyl radical can be methyl, ethyl, or n-propyl. The branched alkyl radical preferably has 1 to 10 carbon atoms. For example, the branched alkyl radical can be i-propyl or t-butyl.

[0012] The aryl radical for R1, R2, R3, R4, R1', R2', R3', and R4' is preferably substituted, in particular by F, alkyl radicals, and / or aryl radicals, or unsubstituted. For example, the aryl radical can be a substituted or unsubstituted phenyl ring. In particular, the aryl radical can be pt-butylphenyl.

[0013] The aliphatic bridge preferably has between 1 and 20 carbon atoms. The aliphatic bridge can be branched or unbranched. The aliphatic bridge can be saturated or unsaturated.

[0014] The aromatic bridge preferably has between 1 and 30 carbon atoms. The aromatics contained in the aromatic bridge can be substituted, in particular with F, alkyl radicals and / or aryl radicals, or unsubstituted. The aromatic bridge can be partially or fully unsaturated. The aromatic bridge can, for example, have a substituted or unsubstituted phenyl ring.

[0015] In the case that X has the ether group, X preferably has the molecular formula (CH2) a O b , where a is in the range from 0 to 20 and b is in the range from 1 to a+1. Peroxide groups are preferably excluded from the ether group.

[0016] In the case that X has the ester group, X preferably has the following structural formula:where a+b is in a range from 0 to 20.

[0017] In the case that X has the amide group, X preferably has the following structural formula:where a+b is in a range from 0 to 20.

[0018] In the case where X has the urethane group, X preferably has the following structural formula:where a+b is in a range from 0 to 20.

[0019] It is preferred that R5 and R5' are, independently of one another, H, D, F, an alkyl radical, or an aryl radical. The alkyl radical for R5 and R5' is preferably unbranched or branched. The unbranched alkyl radical preferably has from 1 to 5 carbon atoms. For example, the unbranched alkyl radical can be methyl, ethyl, or n-propyl. The branched alkyl radical preferably has from 1 to 10 carbon atoms. For example, the branched alkyl radical can be i-propyl or t-butyl. The aryl radical for R5 and R5' is preferably substituted, in particular with F, alkyl radicals, or aryl radicals, or unsubstituted. For example, the aryl radical can be a substituted or unsubstituted phenyl ring. In particular, the aryl radical can be pt-butylphenyl.

[0020] It is preferred that compound A is selected from the group: Compound A1: wherein n=1 and R1, R2, R3, R4, R5, R1', R2', R3', R4' and R5' are independently H or D, Compound A2: wherein n=1 and R1, R2, R3, R4, R1', R2', R3' and R4' are independently H or D and R5 and R5' are t-butyl, and Compound A3, wherein n=2 and R1, R2, R3, R4, R5, R1', R2', R3', R4' and R5' are independently H or D.

[0021] Decarbonylation is preferably carried out without the presence of a catalyst. Decarbonylation can be carried out, for example, with the addition of heat.

[0022] Alternatively, to not providing a catalyst, the decarbonylation may be carried out in the presence of a catalyst K having the structural formula: wherein R6 is an aryl radical, R7 is H, D, an aryl radical or an alkyl radical, wherein M + is selected from the group Li + , N / a + , K+ , Rb + and Cs + , in particular wherein the K + complexed by a crown ether. It has been found that a high yield of carbon monoxide can be achieved with these catalysts. K + and Cs + , because particularly high yields can be achieved with these ions. A further improvement in yield can be achieved if the K + complexed with crown ether.

[0023] The decarbonylation can also be carried out in the presence of a strong base as a catalyst. The strong base can, for example, comprise a tert-butyl oxide, particularly sodium tert-butyl oxide or potassium tert-butyl oxide, and / or KOH.

[0024] Another catalyst for decarbonylation can be ROM, where M is selected from the group consisting of Na, K, Rb, and Cs, and R is selected from the group consisting of H, D, alkyl, allyl, aryl, benzyl, and vinyl. Examples include MeONa, MeOK, and MeORb. Another catalyst for decarbonylation can be R2NM, where M is selected from the group consisting of Na, K, Rb, and Cs, and R is selected from the group consisting of H, D, alkyl, allyl, aryl, benzyl, and vinyl. Examples include Me2NK and ME2NCs. R2NM results in a faster reaction rate than ROM. + gives better yields and faster reaction rates than Na + . Rb + and Cs + gives better yields and faster reaction rates than K + , where K + but better industrial applicability than Rb + and Cs + has.

[0025] The amount of catalyst n Kcompared to the amount of compound A, B or C n A , n B or n C is preferably chosen so that a ratio nKnA∗nmean in a range of 0.05% to 5%, in particular 0.1% to 2%, a ratio nKnB∗nmean in a range of 0.05% to 5%, in particular 0.1% to 2%, and a ratio nKnC∗nmean in a range of 0.05% to 5%, in particular 0.1% to 2%, where n mean is an arithmetic mean of n (ie an arithmetic mean of the chain length of compound A, B or C).

[0026] The aryl radical for R6 is preferably a substituted or unsubstituted phenyl ring with the structural formula:wherein R8, R9, R 10 , R 11 , R 12 are independently H, D, F, an alkyl radical or an aryl radical. Particularly preferred are R8, R9, R 10 , R 11 and R 12independently of one another are H or D or particularly preferably R8, R9, R 10 and R 11 independently H or D and R 12 is t-butyl.

[0027] The aryl radical for R7 is preferably a substituted or unsubstituted phenyl ring with the structural formula:wherein R8', R9', R 10 ', R 11 ', R 12 ' are independently H, D, F, an alkyl radical or an aryl radical. Particularly preferred are R8', R9', R 10 ', R 11 ' and R 12 ' independently of one another are H or D or particularly preferably R8', R9', R 10 ' and R 11 ' independently H or D and R 12 ' is t-butyl.

[0028] It is particularly preferred that R 12 and / or R 12' is a branched alkyl radical, especially i-propyl or t-butyl. This allows the catalyst to be distributed particularly well in compound A, B, or C if both the catalyst and compound A, B, or C are in a solid state.

[0029] It is particularly preferred that R6 and R7 are identical.

[0030] It is particularly preferred that the catalyst K is selected from the group: K1:wherein R6 and R7 are identical and R8, R9, R 10 , R 11 and R 12 independently H or D are K2:where R6 and R7 are identical and R8, R9, R 10 , R 11 and R 12 are independently H or D, K3:where R6 and R7 are identical and R8, R9, R 10 and R 11 are independently H or D and R 12 t-Butyl, K4:where R6 and R7 are identical and R8, R9, R 10 and R 11 are independently H or D and R12 t-Butyl. Compounds K1, K2, K3, and K4 are particularly preferred because the purity of the reaction mass remains very high in the cyclic process involving carbonylation and decarbonylation.

[0031] The alkyl radical for R7 is preferably unbranched or branched. The unbranched alkyl radical preferably has 1 to 5 carbon atoms. For example, the unbranched alkyl radical can be methyl, ethyl, or n-propyl. The branched alkyl radical preferably has 1 to 10 carbon atoms. For example, the branched alkyl radical can be i-propyl or t-butyl.

[0032] It is particularly preferred that R6 and / or R7 has the structural formula: where R 12 H, D, F, an alkyl radical or an aryl radical. R is particularly preferably 12 H or D

[0033] The crown ether is preferably 4,7,13,16,21,24-hexaoxa-1,10-diazabicyclo[8.8.8]hexacosane (Kryptofix® 222).

[0034] It is preferred that the decarbonylation be carried out with the addition of heat. This allows for increased carbon monoxide yields and shortened decarbonylation reaction times, as well as controlling the reaction rate and thus the rate of carbon monoxide release.

[0035] Alternatively, it is preferable to carry out the decarbonylation without the addition of heat. This ensures good energy efficiency.

[0036] It is preferred that the decarbonylation of compound A, B, or C be carried out in a solvent. This is particularly relevant when n=1 or when compound A1 is decarbonylated. The solvent can be, for example, tetrahydrofuran (THF).

[0037] It is preferred that the decarbonylation of compound A, B or C is carried out in a melt of compound A, B or C. This is relevant, for example, when n=1 or when compound A1 is decarbonylated.

[0038] It is preferred that the decarbonylation of compound A, B or C is carried out in a solid state of compound A, B or C. This is relevant, for example, when n>1 or when n=2 or when compound A3 is decarbonylated.

[0039] In a particularly preferred embodiment of the process, N,N-diphenylformamide is synthesized as compound A, which is obtained from triethylammonium formate azeotrope.

[0040] Furthermore, it is preferred that diphenylamine and triethylammonium formate azeotrope are mixed and the mixture is fractionally distilled under reduced pressure, whereby N,N-diphenylformamide is obtained as compound A in the solid phase.

[0041] In the process according to the invention for producing a synthetic fuel, the carbon monoxide is converted using hydrogen. The synthetic fuel can comprise a hydrocarbon and / or an alcohol, in particular methanol and / or ethanol. Exemplary processes for producing the synthetic fuel are Fischer-Tropsch synthesis, involve synthesis gas fermentation, and / or involve methanol synthesis according to the following reaction equation: CO + 2 H2 ⇌ CH3OH. Preparation of compounds A, B and C

[0042] It is preferred that compound A is prepared starting from compound D: and / or wherein compound B is prepared starting from compound E: and / or wherein compound C is prepared starting from compound F:

[0043] Decarbonylation of compounds A regenerates compound D, decarbonylation of compounds B regenerates compound E and decarbonylation of compounds C regenerates compound F.

[0044] Compound A1 is accessible from compound D1, where n=1 and R1, R2, R3, R4, R5, R1', R2', R3', R4' and R5' are independently H or D. Compound A2 is accessible from compound D2, where n=1 and R1, R2, R3, R4, R1', R2', R3' and R4' are independently H or D and R5 and R5' are t-butyl. Compound A3 is accessible from compound D3, where n=2 and R1, R2, R3, R4, R5, R1', R2', R3', R4' and R5' are independently H or D. Compounds D1, D2 and D3 are commercially available. Polyaniline is also commercially available. Polyaniline can be produced by oxidative polymerization of aniline. The chain length of the polyaniline can be adjusted, in particular, by adjusting the ratio of the amount of oxidizing agent to the amount of aniline. Polyaniline derivatives are also accessible via oxidative polymerization.

[0045] It is preferred that compound A is prepared by reacting compound D with formic acid, and / or that compound B is prepared by reacting compound E with formic acid, and / or that compound C is prepared by reacting compound F with formic acid. It is particularly preferred that the formic acid is prepared from a reaction of hydrogen with carbon dioxide. Thus, the amide also acts as a hydrogen storage medium.

[0046] For example, N,N-diphenylformamide (A1) can be prepared by mixing diphenylamine (100 g, 0.591 mol) and formic acid (108 g, 2.35 mol) in a 250 mL round-bottom flask. After 3 days of stirring, a clear solution of A1 was obtained (98% conversion by 1H NMR). The excess formic acid and the condensed water were recovered by flask distillation at 50°C (91.4 g of colorless 82% formic acid, 92% recovery). The remaining white solid was ground and slurried with aqueous HCl (200 mL, 0.5 M), filtered, and rinsed with water (3 × 200 mL). The product was dried at 50 °C under high vacuum for 18 hours to obtain 110 g (95%) of a white solid.

[0047] Further investigations have shown that the compound N,N-diphenylformamide (A1) can be prepared and provided in a particularly preferred manner, namely directly from triethylammonium formate azeotrope, which makes the thermodynamics of the reaction sequence significantly more favorable than formylation using formic acid.

[0048] Using this improved synthesis route for the compound N,N-diphenylformamide (A1), formylation is also possible with triethylammonium formate. This is because the formic acid then does not need to be isolated. CO2 can be scrubbed with amines, a process known as amine scrubbing. During amine scrubbing, the CO2 is chemically absorbed by the amines in a scrubbing solution. The saturated amines or the solution are then heated to 100-140 degrees Celsius, during which a large portion of the CO2 becomes gaseous again and is then separated within the separation system. The reduction of a carbonate with hydrogen is well known; i.e., when triethylammonium formate is used for formylation, the corresponding formate is obtained directly. This is a crucial and particularly advantageous step for completing the reaction sequence. Using this synthesis route, it was shown that diarylamines can be azeotropically formylated with triethylammonium formate at 150 °C under reduced pressure.

[0049] The synthesis of N,N-diphenylformamide (A1), for example, on a 30 g laboratory scale, with recycling of the triethylammonium formate complex 5:2 (azeotrope), is preferably carried out as follows: Diphenylamine (30 g, 0.177 mol) and triethylammonium formate azeotrope (46.7 g, 0.108 mol, corresponding to 0.540 mol of pure FA, formic acid) were placed in a 100 mL round-bottom flask and connected to a fractional distillation apparatus. The mixture was stirred for 2 days at 150 °C under reduced pressure (150-200 mmHg) to obtain a pale yellow solution. During the reaction, a receiver Schlenk tube maintained at -40 °C collected water (low layer) and NEt3 (upper layer) resulting from the reaction. After completion of the formylation reaction, the excess triethylammonium formate azeotrope was recovered as pure reagent by bulb-to-Schlenk distillation at 100 °C (29.3 g, 94% recovery).The white solid remaining in the flask was ground and identified by 1H NMR as diphenylformamide (34.3 g, 97%), which contained only 3% diphenylamine as the sole impurity.

[0050] Thus, a highly advantageous synthetic route for the production of N,N-diphenylformamide (A1) has been demonstrated, which avoids or circumvents the thermodynamically unfavorable preparation of pure formic acid. Considering CO hydrogenation in the presence of bases such as triethylamine, triethylammonium formate is obtained as a distillable azeotrope in good yields. The excess azeotrope can be easily recycled at the end of the reaction.

[0051] In a further alternative, it is preferred that compound A is prepared by reacting compound D with carbon dioxide to form a carbonate and / or a bicarbonate, and then hydrogenating the carbonate and / or the bicarbonate with hydrogen to form compound A, and / or wherein compound B is prepared by reacting compound E with carbon dioxide to form a carbonate and / or a bicarbonate, and then hydrogenating the carbonate and / or the bicarbonate with hydrogen to form compound B, and / or wherein compound C is prepared by reacting compound F with carbon dioxide to form a carbonate and / or a bicarbonate, and then hydrogenating the carbonate and / or the bicarbonate with hydrogen to form compound C.The amide thus acts as a hydrogen storage medium. Compound E can be prepared by oxidative polymerization of a monomer M1:.

[0052] This is described, for example, in Sang-Bum Kim, Ken Harada, and Takakazu Yamamoto, "Preparation of Poly(diphenylamine-4,4'-diyl) and Related Random Copolymers by Organometallic Polycondensation. Electrical, Electrochemical, and Optical Properties" in Macromolecules 1998, 31, 988-993.

[0053] Analogously, compound F can be prepared by oxidative polymerization of a monomer M2:

[0054] All reactions mentioned for the preparation of compounds A, B, C, D, E and / or F can be carried out under anhydrous and / or oxygen-free conditions.

[0055] For the purposes of the invention, other aromatic systems include furans, thiophenes, pyrroles, oxazoles, thiazoles, imidazoles, isoxazoles, isothiazoles, pyrazoles, pyridines, pyrazines, pyrimidine, 1,3,6-triazines, alpha- or gamma pyrones, benzo[b]furan, benzo[b]thiophene, indoles, 2H-isoindoles, Benzothiazoles, 2-Benzothiophenes, 1H-Benzimidazoles, 1H-Benzotriazoles, 1H-Indazoles, 1,3-Benzoxazoles, 2-Benzofuranes, 7H-Purines, Quinolines, Iso-Quinolines, Quinazolines, Quinoxalines, Phthalazines, 1,2,4-Benzotriazines, Pyrido[2,3-d]pyrimidine, Pyrido[3,2-d]pyrimidines, pteridines, acridines, phenazines, benzo[g]ptheridines, 9H-carbazoles, or bipyridine derivatives. In particular, it is conceivable to carbonylate polypyrrole, polypyrrole derivatives, poly(indole-co-thiophene), poly(indole-co-thiophene) derivatives, poly[(pyrrole-2,5-diyl)-co-(4-hydroxylbenzylidene)], poly[(pyrrole-2,5-diyl)-co-(4-hydroxylbenzylidene)] derivatives, polyindole, or polyindole derivatives to formamides and to decarbonylate these formamides. Production of catalysts

[0056] The catalysts Li + [NR6R7 - ] can be prepared by deprotonation of HNR6R7 with n-BuLi. In one example, lithium diphenylamide was prepared by adding 1.2 equivalents of n-BuLi (5 mL, 1.12 M) dropwise to a solution of diphenylamine (846 mg, 5.00 mmol) in n-hexane (25 mL). The reaction mixture was stirred until a white precipitate formed. After 1.5 h of stirring, the resulting suspension was filtered through GF / B (Whatman® glass microfiber filter, grade GF / B), washed with n-pentane (3 × 10 mL), and dried in HV (high vacuum) to afford 840 mg (96%) of a white solid.

[0057] The catalysts Na + [NR6R7 -] can be prepared by deprotonation of HNR6R7 with sodium hydride. In one example, sodium diphenylamide was prepared by dissolving diphenylamine (1692 mg, 10.00 mmol) and sodium hydride (240 mg, 10.0 mmol), each in THF (10 mL). The sodium hydride solution was added dropwise to the diphenylamine solution to form a light yellow solution. After stirring overnight, the reaction mixture was filtered through GF / B, and the solution was dried overnight in HV. The resulting solid was washed with n-pentane (3 × 5 mL) and dried in HV to afford a white solid (1797 mg, 94%).

[0058] The catalysts K + [NR6R7 -] can be prepared by deprotonation of HNR6R7 with benzylpotassium. In one example, potassium diphenylamide (K1) was prepared by dissolving benzylpotassium (8.083 g, 62.07 mmol) and diphenylamine (10.51 g, 62.11 mmol) each in THF (50 mL). Both solutions were pre-chilled in the freezer. The orange benzylpotassium solution was added dropwise to the diphenylamine solution to form a yellowish solution. After stirring for 1.5 h, the reaction mixture was filtered through GF / B, and the yellowish solution was dried overnight in HV. The resulting solid was washed with n-pentane (3 × 25 mL) and dried in HV to afford 13.19 g (97%) of a yellow solid. In another example, potassium bis(4-(t-butyl)phenyl)amide (K3) was prepared by dissolving benzylpotassium (1.388 g, 10.66 mmol) and bis(4-(t-butyl)phenyl)amine (3.007 g, 10.68 mmol) each in THF (10 mL). Both solutions were pre-chilled in the freezer.The orange benzylpotassium solution was added dropwise to the bis(4-(t-butyl)phenyl)amine solution to form a yellowish solution. After stirring for 2 hours, the reaction mixture was filtered through GF / B, and the yellowish solution was dried overnight in HV. The resulting solid was washed with n-pentane (3 × 5 mL) and dried in HV to yield 2.946 g of yellow solid (86%).

[0059] The catalysts crown ether-K + [NR6R7 - ], where the K + -cation is complexed by the crown ether, can be prepared by adding the crown ether to a solution of the uncomplexed catalyst K + [NR6R7 -] In one example, Kryptofix® 222 potassium diphenylamide (K@K22 diphenylamide) was prepared by dissolving potassium diphenylamide (186 mg, 0.897 mmol) and Kryptofix® 222 (336 mg, 0.893 mmol) each in THF (3 mL). The Kryptofix® 222 solution was added dropwise to the potassium diphenylamide solution. After stirring for 20 minutes, the reaction mixture was filtered through GF / B, and the resulting solid was dried overnight in HV. The resulting solid was washed with n-pentane (3 × 3 mL) and dried in HV to afford 279 mg (54%) of the pale yellow solid. In another example, Kryptofix® 222 potassium bis(4-(t-butyl)phenyl)amide was prepared by dissolving potassium bis(4-(t-butyl)phenyl)amide (184 mg, 0.575 mmol) and Kryptofix® 222 (217 mg, 0.577 mmol) each in THF (3 mL). The Kryptofix® 222 solution was added dropwise to the potassium bis(4-(t-butyl)phenyl)amide solution to form a yellowish solution.After stirring for 2 hours, the reaction mixture was filtered through GF / B, and the yellowish solution was dried overnight in HV. The resulting solid was washed with n-pentane (3 × 3 mL) and dried in HV to yield 384 mg (96%) of the pale yellow solid.

[0060] The catalysts Cs + [NR6R7 -] can be prepared by reducing HNR6R7 with cesium. In one example, cesium diphenylamide (K2) was prepared by adding diphenylamine (508 mg, 3.00 mmol) to cesium (412 mg, 3.10 mmol) in 5 mL of THF. The mixture immediately turned dark orange and evolved a gas (presumably hydrogen). The reaction mixture was stirred overnight at room temperature. The completion of the reaction was indicated by the cessation of gas evolution. The resulting mixture was filtered to remove the solid, and then n-pentane was slowly added to the mixture until all the precipitate dissolved in the solution and the solution became clear. The pale yellow solid was filtered over GF / B, washed with n-pentane (3 × 5 mL), and dried in HV to afford 885 mg (98%) of a yellow solid.In another example, cesium bis(4-(t-butyl)phenyl)amide (K4) was prepared by adding bis(4-(t-butyl)phenyl)amine (844 mg, 3.00 mmol) to cesium (412 mg, 3.10 mmol) in 5 mL of THF. The mixture immediately turned dark orange and evolved a gas (presumably hydrogen). The reaction mixture was stirred overnight at room temperature. The completion of the reaction was indicated by the cessation of gas evolution. The resulting mixture was filtered to remove the solid, and then n-pentane was slowly added to the mixture until all the precipitate dissolved in the solution and the solution became clear. The pale yellow solid was filtered over GF / B, washed with n-pentane (3 × 5 mL), and dried in HV to afford 1153 mg (93%) of a yellow solid.

[0061] All reactions for the preparation of the catalysts can be carried out under anhydrous and / or oxygen-free conditions. Investigation of decarbonylation

[0062] General procedure for the decarbonylation of N,N-diphenylformamide (A1) under constant volume: N,N-diphenylformamide (79 mg, 0.4 mmol) was dissolved in THF-D8 (0.3 ml) and transferred into a Young's NMR tube (total volume of 1 cm 3 ) with a screw-on Teflon cap. Metal N,N-diphenylamide (0.4 mmol) was dissolved in THF (1 ml). 10 µl of this solution was taken and added to the N,N-diphenylformamide solution in the Young's NMR tube. The reaction was monitored hourly for 66 hours at 25 °C using 1 H-NMR analysis. The results are presented in Fig.Figure 1 shows the conversion c of the amide to the amine and carbon monoxide plotted against time. While Ph2NLi yielded approximately 3% conversion, Ph2NNa and Ph2NK showed 70% and 95% conversion, respectively, after 68 hours. The cesium amide K2 exhibits even faster kinetics in the initial phase of the reaction, but the conversion stagnates at 88%, suggesting equilibrium with the reverse reaction (i.e., carbonylation of diphenylamine). The potassium Kryptofix® 222 complex exhibits a similarly high initial activity, achieving a conversion of approximately 95%.

[0063] General procedure for the decarbonylation of N,N-diphenylformamide (A1) to carbon monoxide and diphenylamine under solvent-free conditions: Under an inert atmosphere, clean N,N-diphenylformamide (1972 mg, 10.00 mmol) and a metal N,N-diphenylamide (1 mol%) were added to a 25 mL Schlenk flask. The reaction mixture was connected to an oil bubbler and heated to 70 °C for 3 hours, forming a melt of the mixture. During this time, gas evolution (CO) was observed. The water displacement method was used to determine and measure the volume of the gaseous products. Fig. 2, where the conversion c of the amide into the amine and carbon monoxide is plotted against time, shows similar decarbonylation rates as in Fig. 1 and an almost quantitative conversion when the catalysts K1 (both with the uncomplexed K + -cation as well as with the K complexed with Kryptofix® 222+ -cation) and K2 can be used.

[0064] General procedure for the decarbonylation of N,N'-(1,4-phenylene)bis(N-phenylformamide) (A3) to carbon monoxide and N,N'-diphenyl-p-phenylenediamine under solvent-free conditions: Under an inert atmosphere, pure N,N'-(1,4-phenylene)bis(N-phenylformamide) (1790 mg, 5 mmol) and metal bis(4-(tert-butyl)phenyl)amide (1 mol%) were mixed thoroughly with grinding for 5 minutes and then transferred to a 25 mL Schlenk flask. The reaction mixture was connected to a reflux condenser, previously connected to an oil bubbler, and heated to the desired temperature for 6 hours. During this time, gas evolution (CO) was observed. The water displacement method was used to determine and measure the volume of the gaseous products. Fig.Figure 3, in which the conversion c of the amide into the amine and carbon monoxide is plotted against time, shows the results for K3 (without crown ether). A solid mixture of A3 and K3 is stable at room temperature. Almost quantitative conversion is achieved at 90 °C when the catalysts K3 (both with the uncomplexed K + -cation as well as with the K complexed with Kryptofix® 222 + -cation) and K4 can be used.

[0065] N,N-Diphenylformamide (1972 mg, 10.00 mmol) and the catalyst (1 mol%) were added to a 25 mL Schlenk flask. The reaction mixture was heated to 70 °C for 3 hours, and gas evolution was monitored. At the end of the reaction (when gas evolution ceased), the mixture was cooled to room temperature, solidified, and precipitated using 1 H-NMR analysis was used to determine the amount of decomposition. The results are presented in the table below: catalyst c / % speed tBuOK 100 best speed in this table tBuONa 100 Similar to KOH HOK 100 Similar to tBuONa HONa 0 No reaction

[0066] The decarbonylation can be carried out under anhydrous and / or oxygen-free conditions.

[0067] The screening of common primary and secondary, linear and cyclic alkyl and aryl formamides identified diphenylformamide (A1) as a particularly promising lead structure for the decarbonylation reaction. It can be synthesized either at room temperature by reacting PH2NH with formic acid on a 100 g scale or at 150 °C under reduced pressure using a 3:1 excess of the more economical triethylammonium formate azeotrope. The excess azeotrope can be easily recycled at the end of the reaction. Thus, the process for producing carbon monoxide by decarbonylation of the compound diphenylformamide (A1) is particularly interesting, as the demonstrated synthesis pathway for diphenylformamide (A1) using a triethylammonium formate azeotrope offers significant economic advantages.In a particularly preferred embodiment of the process, diarylamines are efficiently formylated at room temperature with formic acid or at 150 °C under reduced pressure with triethylammonium formate. QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited non-patent literature

[0000] Sang-Bum Kim, Ken Harada, and Takakazu Yamamoto, "Preparation of Poly(diphenylamine-4,4'-diyl) and Related Random Copolymers by Organometallic Polycondensation. Electrical, Electrochemical, and Optical Properties" in Macromolecules 1998, 31, 988-993

[0052]

Claims

[1] A process for producing carbon monoxide by decarbonylation of a compound A, B or C, wherein compound A has the structural formula:, compound B has the structural formula:, and compound C has the structural formula: wherein R1, R2, R3, R4, R1', R2', R3' and R4' are independently H, D, F, an alkyl group or an aryl group, wherein X is an aliphatic bridge, an aromatic bridge, an ether group, an ester group, an amide group or a urethane group, wherein n is in a range of 1 to 100,000. [2] The process according to claim 1, wherein R5 and R5' are independently H, D, F, an alkyl radical or an aryl radical. [3] A process according to claim 1 or 2, wherein the decarbonylation is carried out without the presence of a catalyst. [4] A process according to claim 3, wherein the decarbonylation is carried out with the addition of heat. [5] A process according to claim 1 or 2, wherein the decarbonylation is carried out in the presence of a catalyst K having the structural formula: wherein R6 is an aryl radical, R7 is H, D, an aryl radical or an alkyl radical, wherein M + is selected from the group Li + , N / a + , K + , Rb + and Cs + , in particular wherein the K + complexed by a crown ether. [6] A process according to claim 5, wherein the decarbonylation is carried out with the addition of heat. [7] A process according to claim 5, wherein the decarbonylation is carried out without the addition of heat. [8] A process according to any one of claims 1 to 7, wherein the decarbonylation of compound A, B or C is carried out in a solvent. [9] A process according to any one of claims 1 to 7, wherein the decarbonylation of compound A, B or C is carried out in a melt of compound A, B or C. [10] The process according to any one of claims 1 to 7, wherein the decarbonylation of the compound A, B or C is carried out in a solid state of the compound A, B or C. [11] Process according to any one of claims 1 to 10, wherein compound A is prepared starting from compound D:and / or wherein compound B is prepared starting from compound E:and / or wherein compound C is prepared starting from compound F: [12] A process according to claim 11, wherein compound A is prepared by reacting compound D with formic acid and / or compound B is prepared by reacting compound E with formic acid and / or compound C is prepared by reacting compound F with formic acid. [13] A process according to claim 11, wherein compound A is prepared by reacting compound D with carbon dioxide to form a carbonate and / or a bicarbonate, and then hydrogenating the carbonate and / or the bicarbonate with hydrogen to form compound A, and / or wherein compound B is prepared by reacting compound E with carbon dioxide to form a carbonate and / or a bicarbonate, and by subsequently hydrogenating the carbonate and / or the bicarbonate with hydrogen to form compound B, and / or wherein compound C is prepared by reacting compound F with carbon dioxide to form a carbonate and / or a bicarbonate, and then hydrogenating the carbonate and / or the bicarbonate with hydrogen to form compound C. [14] The process according to claim 11, wherein N,N-diphenylformamide is synthesized as compound A, which is obtained from triethylammonium formate azeotrope. [15] A process according to claim 14, wherein diphenylamine and triethylammonium formate azeotrope are mixed and the mixture is fractionally distilled under reduced pressure to recover N,N-diphenylformamide in the solid phase. [16] A process for producing a synthetic fuel, wherein the carbon monoxide produced by a process according to any one of claims 1 to 13 is reduced using hydrogen. [17] Method according to claim 16, wherein the synthetic fuel comprises a hydrocarbon and / or an alcohol, in particular methanol and / or ethanol.

Images