Novel carboxy ligands and use thereof in catalysts
Patent Information
- Application Number
- EP2023734644
- Authority / Receiving Office
- EP · EP
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2022-06-24
- Filing Date
- 2023-06-22
- Publication Date
- 2025-04-30
AI Technical Summary
The use of tin-containing catalysts in producing compounds with urethane groups is problematic due to their toxicity, and existing alternatives lack effective catalytic activity and stability, particularly at room temperature.
Development of a bismuth-containing catalyst system utilizing specific carboxy ligands that form a bismuth-containing catalyst with three ligands, which provides comparable catalytic activity to tin-containing catalysts without the toxicity issues and includes a mechanism to inhibit reaction initiation, extending the 'pot life' of reactive materials.
The bismuth-containing catalyst system achieves high catalytic activity in forming compounds with urethane groups, inhibiting reaction initiation for longer pot lives, and operates effectively at room temperature without requiring acidic forms, thus offering a safer and more stable alternative to tin-based catalysts.
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Abstract
Description
[0001] New carboxy ligands and their use in catalysts
[0002] Description
[0003] The invention relates to a carboxy ligand as such, which is defined by the general formula (I) listed in the following text. Furthermore, the invention relates to a bismuth-containing catalyst as such according to the general formula (II), wherein the bismuth-containing catalyst comprises three carboxy ligands of the general formula (I). The present invention further relates to a process for preparing such a carboxy ligand and to a process for preparing such a bismuth-containing catalyst. In the preparation of the carboxy ligand according to the invention, a precursor of a ligand according to the general formula (III) is also obtained, likewise according to the invention. The present invention further relates to the use of such a bismuth-containing catalyst for preparing compounds containing a urethane group.
[0004] WO 2020 / 160939 relates to a bismuth-containing catalyst as such, which is defined therein by a general formula (I). The bismuth-containing catalyst according to WO 2020 / 160939 contains at least one radical R 1 which, according to general formula (II), contains a carboxyl fragment, wherein a first carbon atom (α-carbon) is bonded to the carbon atom of the carboxyl group, which in turn is directly substituted by at least one aromatic. WO 2020 / 160939 further relates to a process for preparing such a bismuth-containing catalyst and the use of such a bismuth-containing catalyst for preparing compounds containing a urethane group.
[0005] WO 2018 / 069018 relates to a coating system comprising components (A) to (C) and optionally further components. Component (A) is at least one compound containing polyhydroxy groups, and component (B) is at least one compound containing polyisocyanates. Component (C), in contrast, is a catalyst comprising at least two salts of an aliphatic monocarboxylic acid having at least 4 carbon atoms. The metal component of the first salt is bismuth (Bi), while the second salt has magnesium (Mg), sodium (Na), potassium (K), or calcium (Ca) as its metal component.According to a first option, the coating systems according to WO 2018 / 069018 can be designed such that all components are present separately from one another, i.e., the individual components are not mixed with one another. According to a second option of the corresponding coating system, the respective components can also be present completely or at least partially mixed with one another. The preparation of compounds containing a urethane group (urethane bond) has also been known for a long time. A compound containing a urethane group is generally obtained by reacting a compound containing an isocyanate group with a compound containing a hydroxyl group. The reaction generally takes place in the presence of a catalyst.Although tin-containing catalysts show very high activity in such reactions, the use of such tin-containing catalysts, especially alkyl tin compounds, should be avoided due to their (very high) toxicity.
[0006] The object of the present invention was therefore to provide a novel ligand and / or a catalyst comprising such a novel ligand, which catalyst can be used for the preparation of compounds containing a urethane group.
[0007] The task is solved by a ligand according to the general formula (I) in which the variables are defined as follows:
[0008] A is N or (NH) + (X)-,
[0009] B is CH2, CH, CR 5 or CR 5 H,
[0010] D is CH2, CH, CR 6 or CR 6 H,
[0011] E is H or alkali,
[0012] R1 is H or Ci-Cio-alkyl,
[0013] R 2 is H or Ci-Cio-alkyl,
[0014] R 3 is H or Ci-Cio-alkyl,
[0015] R 4 is H or Ci-Cio-alkyl,
[0016] R 5 is Ci-C -alkyl,
[0017] R 6 is Ci-C alkyl or R 5 and R 6 together form a bridge with four
[0018] carbon atoms, where B, D, R 5 and R 6 together can form a benzene fragment, which may be combined with a radical R 7 can be at least monosubstituted,
[0019] R 7 is Ci-Cio-alkyl, X is BF4, OH or halogen, where
[0020] A (NH) + (X)- is,
[0021] B CH2, CH, CR 5 or CR 5 H is,
[0022] D CH2, CH, CR 6 or CR 6 H is,
[0023] EH is,
[0024] R1 C2-C4 alkyl,
[0025] R 2 C2-C4 alkyl,
[0026] R 3 H or methyl,
[0027] R 4 H or methyl is
[0028] R 5 and R 6 together form a bridge with four carbon atoms, provided that B and D are not CH2 or CH, where B, D, R 5 and R 6 together preferably form an unsubstituted benzene fragment,
[0029] X BF4ist.
[0030] Furthermore, the problem is solved by a bismuth-containing catalyst according to the general formula (II) in which the variables are defined as follows:
[0031] A is N or (NH) + (X)-,
[0032] B is CH2, CH, CR 5 or CR 5 H,
[0033] D is CH2, CH, CR 6 or CR 6 H,
[0034] R 1 is H or Ci-Cio-alkyl,
[0035] R 2 is H or Ci-Cio-alkyl,
[0036] R 3 is H or Ci-Cio-alkyl,
[0037] R 4 is H or Ci-Cio-alkyl,
[0038] R 5 is Ci-C -alkyl,
[0039] R 6 is Ci-C alkyl or R 5 and R 6 together form a bridge with four
[0040] carbon atoms, where B, D, R 5 and R 6 together can form a benzene fragment, which may be combined with a radical R 7 can be at least monosubstituted,
[0041] R 7 is Ci-C -alkyl,
[0042] X is BF4, OH or halogen, where in each of the three ligands of the bismuth-containing catalyst the respective variables can be defined independently of the other two ligands or all three ligands are defined identically.
[0043] The bismuth-containing catalysts according to the invention are distinguished, among other things, by the fact that the use of toxic tin-containing catalysts in the production of compounds containing a urethane group can be avoided. The bismuth-containing catalysts according to the invention exhibit comparable catalyst activity to known representatives of effective, catalytically active, yet toxic tin-containing catalysts.
[0044] Furthermore, it was surprisingly found that the use of the bismuth-containing catalyst according to the invention according to general formula (II) in urethane reactions results in an inhibited reaction in the first few minutes due to the use of the ligand according to the invention of general formula (I). This is of particular interest for applications requiring inhibition at room temperature. This blocking of the catalyst can lead to longer pot lives in PU applications. Pot life, according to the invention, refers to how long reactive materials can be processed in the mixed state without any observed loss of quality in the corresponding application. Pot life is determined via the gel time.
[0045] Furthermore, the bismuth-containing catalysts of the invention do not require the catalyst to be present as a salt in the corresponding acid. The bismuth-containing catalysts of the invention can therefore also be used without the presence of the corresponding acid to form compounds with urethane groups with high catalytic activity.
[0046] From a scientific point of view, it is justifiable to choose a notation / representation for the bismuth-containing catalysts according to general formula (II) according to the invention, instead of the salt notation used in the present application, in which a chemical bond between the bismuth central atom and the three ligands according to general formula (II) is fully or at least partially formed. In other words, this means that the bismuth central atom is not present as a positively charged cation, and the corresponding ligands are not present as negatively charged anions, but instead the corresponding charge forms a chemical bond between the corresponding ligands on the one hand and the bismuth central atom on the other. Within the scope of the present invention, such a definition, not based on a salt, therefore also describes the disclosed bismuth-containing catalysts according to the invention.
[0047] In the context of the present invention, definitions such as Ci-C -alkyl, as for example above for the radical R 1 in formula (I) is defined as an alkyl radical having a carbon number of 1 to 10, where any substituents present are not taken into account in the carbon number. The alkyl radical can be linear or branched and, where appropriate, cyclic. Alkyl radicals which have both a cyclic and a linear component also fall under this definition. The same applies to other alkyl radicals, such as a C1-C12 alkyl radical or a C1-C12 alkyl radical. Examples of alkyl radicals are methyl, ethyl, n-propyl, sec-propyl, n-butyl, sec-butyl, isobutyl, 2-ethylhexyl, tertiary-butyl (tert-Bu / t-Bu), pentyl, hexyl, heptyl, cyclohexyl, octyl, nonyl or decyl.
[0048] In the context of the present invention, the term “halogen”, as defined above for the radical X in formula (I), for example, means that the substituent (radical) is fluorine, chlorine, bromine or iodine, preferably X is fluorine or chlorine, particularly preferably chlorine.
[0049] In the context of the present invention, the term “unsubstituted or at least monosubstituted by Ci-C alkyl benzene” means, for example, in connection with the radical R 7 Formula (I) defines that benzene can be present either in unsubstituted form or has at least one C-C alkyl substituent (monosubstituted). If one or more substituents (e.g., bisubstituted, trisubstituted, or even more highly substituted) are present, the corresponding substituents are selected independently of one another from the respective substituent groups indicated.
[0050] If a corresponding residue, such as R 1, due to the definition of, for example, formula (II) (in conjunction with formula (I)) can occur two or more times, the individual radicals R 1 are selected completely independently of each other according to the respective definitions. Unless otherwise stated in the following text, this also applies mutatis mutandis to all other residues, such as R 2 , R 3 , R 5 and / or R 6 .
[0051] Unless otherwise stated in the following description, the respective definitions of the radicals R 1 to R 7 The respective unsubstituted definitions are preferred. The present invention is further defined below.
[0052] A first object of the present invention is a ligand according to the general formula (I) in which the variables are defined as follows:
[0053] A is N or (NH) + (X)-,
[0054] B is CH2, CH, CR 5 or CR 5 H,
[0055] D is CH2, CH, CR 6 or CR 6 H,
[0056] E is H or alkali,
[0057] R 1 is H or Ci-Cio-alkyl,
[0058] R 2 is H or Ci-Cio-alkyl,
[0059] R 3 is H or Ci-Cio-alkyl,
[0060] R 4 is H or Ci-Cio-alkyl,
[0061] R 5 is Ci-C -alkyl,
[0062] R 6 is Ci-C alkyl or R 5 and R 6 together form a bridge with four carbon atoms, where B, D, R 5 and R 6 together can form a benzene fragment, which may be combined with a radical R 7 can be at least monosubstituted,
[0063] R 7 is Ci-C -alkyl,
[0064] X is BF4, OH or halogen.
[0065] For a specialist it is clear that in case R 5 and R 6 together form a bridge with four carbon atoms, where B, D, R 5 and R 6 together form a benzene fragment, B and D are defined as follows:
[0066] B is CR 5 and
[0067] D is CR 6 , where the residues R 5 and R 6 have a total of 4 carbon and 4 hydrogen atoms and there are six delocalized TT electrons between the 6 carbon atoms. In other words, the residues R 1 , R 2 , R 4 , R 5 , B and D form a benzimidazole residue.
[0068] Furthermore, it is also possible for a double bond to be present between B and D instead of a single bond. In this case, the following applies:
[0069] B is CH or CR 5 and
[0070] D is CH or CR 6 .
[0071] According to the invention, it is preferred that in the general formula (I) i) B and D and optionally R 5 and R 6 each have the same definition, where B, D, R 5 and R 6 together optionally form a benzene fragment, which is preferably unsubstituted, and / or ii) R 1 and R 2 each have the same definition, and / or ill) R 3 and R 4 each have the same definition, and / or iv) alkali is sodium or potassium, preferably sodium, provided that E is alkali, and / or v) halogen is chlorine or bromine, provided that X is halogen.
[0072] However, it is also possible that R 1 and R 2 are different and / or R 3 and R 4 are different. Of course, it is also possible that B and D are different.
[0073] According to the invention, it is more preferred that in the general formula (I)
[0074] A (NH) + (X)- is,
[0075] B CH2, CH, CR 5 or CR 5 H is,
[0076] D CH2, CH, CR 6 or CR 6 H is,
[0077] EH is,
[0078] R 1 C2-C4 alkyl,
[0079] R 2 C2-C4 alkyl,
[0080] R 3 H or methyl,
[0081] R 4 H or methyl is
[0082] R 5 and R 6 together form a bridge with four carbon atoms, provided that B and D are not CH2 or CH, where B, D, R 5 and R 6 together preferably form an unsubstituted benzene fragment, X is BF4.
[0083] Particularly preferred ligands of the general formula (I) according to the invention are 4-carboxy-N-(1,3-diisopropyl-1,3-dihydro-2H-benzo[d]imidazol-2-ylidene)-2,6-dimethylbenzenaminium tetrafluoroborate or 4-carboxy-N-(1,3-di-tert-butylimidazolidin-2-ylidene)benzenaminium tetrafluoroborate.
[0084] Another object of the present invention is a bismuth-containing catalyst according to the general formula (II) in which the variables are defined as follows:
[0085] A is N or (NH) + (X)
[0086] B is CH2, CH, CR 5 or CR 5 H,
[0087] D is CH2, CH, CR 6 or CR 6 H,
[0088] R 1 is H or Ci-Cio-alkyl,
[0089] R 2 is H or Ci-Cio-alkyl,
[0090] R 3 is H or Ci-Cio-alkyl,
[0091] R 4 is H or Ci-Cio-alkyl,
[0092] R 5is Ci-C -alkyl,
[0093] R 6 is Ci-C alkyl or R 5 and R 6 together form a bridge with four
[0094] carbon atoms, where B, D, R 5 and R 6 together can form a benzene fragment, which may be combined with a radical R 7 can be at least monosubstituted,
[0095] R 7 is Ci-C -alkyl,
[0096] X is BF4, OH, or halogen, where the respective variables in each of the three ligands of the bismuth-containing catalyst can be defined independently of the other two ligands, or all three ligands can be defined identically. However, it is preferred that all three ligands of the bismuth-containing catalyst be defined identically according to general formula (II).
[0097] The above definitions and preferences with regard to the ligand according to the general formula (I) also apply analogously to the present bismuth-containing catalyst according to the general formula (II).
[0098] According to the invention, it is preferred that i) B and D and optionally R 5 and R 6 each have the same definition, where B, D, R 5 and R 6 together optionally form a benzene fragment, which is preferably unsubstituted, and / or ii) R 1 and R 2 each have the same definition, and / or ill) R 3 and R 4 each have the same definition, and / or iv) halogen is chlorine or bromine, provided that X is halogen.
[0099] Here, too, it is possible that R 1 and R 2 are different and / or R 3 and R 4are different. Of course, it is also possible that B and D are different.
[0100] It is particularly preferred that in the general formula (II)
[0101] A (NH) + (X)- is,
[0102] B CH2, CH, CR 5 or CR 5 H is,
[0103] D CH2, CH, CR 6 or CR 6 H is,
[0104] R 1 C2-C4 alkyl,
[0105] R 2 C2-C4 alkyl,
[0106] R 3 H or methyl,
[0107] R 4 H or methyl is
[0108] R 5 and R 6 together form a bridge with four carbon atoms, provided that B and D are not CH2 or CH, where B, D, R 5 and R 6 together preferably form an unsubstituted benzene fragment,
[0109] X BF4ist.
[0110] The bismuth-containing catalyst according to the general formula (II) is particularly preferably bismuth(III)-(4-((1,3-di-tert-butylimidazolidin-2-ylidene)ammonio)benzoate)tetrafluoroborate)3([Bi(O2C(PNsltBu)H)3][BF4]3). However, it is also possible that another metal central atom is used as the central atom instead of a bismuth central atom in the catalyst according to the invention, for example a zinc, titanium or zirconium central atom.
[0111] Therefore, a further subject matter of the present invention is also a metal-containing catalyst which is prepared by reacting at least one compound of the general formula (I) with at least one metal-containing compound, wherein the metal-containing compound is preferably a bismuth-, zinc-, titanium- or zirconium-containing compound, preferably a bismuth-containing compound.
[0112] Another object of the present invention is a precursor of a ligand according to the general formula (III) in which the variables are defined as follows:
[0113] A is N or (NH) + (X)
[0114] B is CH2, CH, CR 5 or CR 5 H,
[0115] D is CH2, CH, CR 6 or CR 6 H,
[0116] R 1 is H or Ci-Cio-alkyl,
[0117] R 2 is H or Ci-Cio-alkyl,
[0118] R 3 is H or Ci-Cio-alkyl,
[0119] R 4 is H or Ci-Cio-alkyl,
[0120] R 5 is Ci-C -alkyl,
[0121] R 6 is Ci-C alkyl or R 5 and R 6 together form a bridge with four
[0122] carbon atoms, where B, D, R 5 and R 6 together can form a benzene fragment, which may be combined with a radical R 7 can be at least monosubstituted,
[0123] R 7 is Ci-Cio-alkyl,
[0124] X is BF4, OH or halogen
[0125] Y is halogen, preferably Br.
[0126] Preferably, in the general formula (III), A (NH) + (X)' is,
[0127] B CH2, CH, CR 5 or CR 5 H is,
[0128] D CH2, CH, CR 6 or CR 6 H is,
[0129] R 1 C2-C4 alkyl,
[0130] R 2 C2-C4 alkyl,
[0131] R 3 H or methyl,
[0132] R 4 H or methyl is
[0133] R 5 and R 6 together form a bridge with four carbon atoms, provided that B and D are not CH2 or CH, where B, D, R 5 and R 6 together preferably form an unsubstituted benzene fragment,
[0134] X BF4ist.
[0135] The above definitions and preferences with regard to the ligand according to the general formula (I) and with regard to the bismuth-containing catalyst according to the general formula (II) also apply analogously to the present precursor of a ligand according to the general formula (III).
[0136] The precursor N-(4-bromo-2,6-dimethylphenyl)-1,3-diisopropylbenzimidazol-2-imine (Br(P"NBiPr)) or N-(4-bromophenyl)-1,3-di-tert-butylimidazolidin-2-imine (Br(PNsltBu)) is very particularly preferred.
[0137] The present invention further provides a process for preparing a ligand according to the invention according to the general formula (I), wherein the ligand according to the invention according to the general formula (I) is obtained from the corresponding precursor of a ligand of the general formula (III) by carboxylating this precursor in the presence of a catalyst.
[0138] A suitable catalyst for carboxylation is, for example, n-butyllithium.
[0139] The present invention further provides a process for preparing a bismuth-containing catalyst of general formula (II), wherein i) at least one compound of general formula (I) is reacted with ii) at least one bismuth-containing compound selected from Bi2O3, bismuth carbonate, bismuth bicarbonate, bismuth halide, bismuth carboxylate, Bi(C6-C14-aryl)3, Bi(C1-C12-alkyl)3, or metallic bismuth. In principle, any bismuth-containing compound suitable for forming the bismuth central atom in the bismuth-containing catalyst of general formula (II) according to the invention by reaction with the corresponding compound of general formula (I) can be used in the process according to the invention for preparing a bismuth-containing catalyst of general formula (II). Bismuth-containing compounds as such are known to the person skilled in the art.If a bismuth halide is used as a bismuth-containing compound according to the invention, it is preferably a chlorine-containing compound, in particular Bids.
[0140] Preferably, the bismuth-containing compound is selected from Bi2Os, BiCh, Bi(C6H5)3 or metallic bismuth.
[0141] Preferably, the bismuth-containing catalysts according to the invention according to the general formula (II) are prepared by reacting at least one compound of the general formula (I) with at least one bismuth-containing compound, wherein i) the reaction is carried out under a protective atmosphere and / or in the presence of at least one solvent, in particular toluene, acetonitrile or tetrahydrofuran, and / or ii) the reaction is carried out for at least 10 hours and / or at a temperature of at least 100°C, and / or iii) following the reaction, volatile constituents are removed, the bismuth-containing catalyst is dried under reduced pressure and / or recrystallization is carried out.
[0142] A further object of the present invention is the use of at least one bismuth-containing catalyst according to the above definitions for the preparation of compounds containing a urethane group.
[0143] A further embodiment of the present invention comprises a ligand according to the general formula (I) in which the variables are defined as follows:
[0144] A is N or (NH) + (X)
[0145] B is CH2, CH, CR 5 or CR 5 H,
[0146] D is CH2, CH, CR 6 or CR 6 H,
[0147] E is H or alkali,
[0148] R 1 is H or Ci-Cio-alkyl,
[0149] R 2 is H or Ci-Cio-alkyl,
[0150] R 3 is H or Ci-Cio-alkyl,
[0151] R 4 is H or Ci-Cio-alkyl,
[0152] R 5 is Ci-C -alkyl,
[0153] R 6 is Ci-C alkyl or R 5 and R 6 together form a bridge with four carbon atoms, where B, D, R 5 and R 6together can form a benzene fragment, which may be combined with a radical R 7 can be at least monosubstituted,
[0154] R 7 is Ci-C -alkyl,
[0155] X is BF4, OH or halogen.
[0156] The invention is illustrated below using examples.
[0157] N-(4-Bromo-2, 6-dimethylphenyl) - 1, 3-diisopropylbenzimidazole-2-imine (Br(P' 'NBiPr) )
[0158] The precursor 2-chloro-1,3-diisopropylbenzimidazolium tetrafluoroborate was synthesized according to the following literature procedure: LFB Wilm, T. Eder, C. Mück-Lichtenfeld, P. Mehlmann, M. Wünsche, F. Buß and F. Dielmann, Green Chem., 2019, 21, 640-648.
[0159] In a Schlenk flask, 2-chloro-1,3-diisopropylbenzimidazolium tetrafluoroborate (3.38 g, 10.4 mmol, 1.00 eq.) and 4-bromo-2,6-xylidine (2.08 g, 10.4 mmol, 1.00 eq.) were dissolved in 35 mL of MeCN. After the addition of EtsN (2.90 mL, 20.8 mmol, 2.00 eq.), the reaction mixture was heated for 3 days at 100 °C. The reaction progress was monitored by 1 H NMR spectroscopy. The solvent was then removed under vacuum, and the residue was extracted with hot n-hexane (50 mL). The solution was stored overnight at -20 °C, yielding the product Br(P"NBiPr) as a crystalline white solid. The product Br(P"NBiPr) was subsequently dried at 80 °C for 24 h under vacuum. Yield: 89% (3.90 g, 9.74 mmol).
[0160] N-(4-Bromophenyl)-1,3-di-tert-butylimidazolidin-2-imine (Br(PNsltBu); catalyst according to Comparative Example 2)
[0161] The precursor 2-chloro-1,3-di-tert-butylimidazolium chloride was also synthesized according to the above literature procedure.
[0162] In a Schlenk flask, 2-chloro-1,3-di-tert-butyl-imidazolium chloride (12.5 g, 49.5 mmol, 1.00 eq.) and p-bromoaniline (8.52 g, 49.5 mmol, 1.00 eq.) were dissolved in 150 mL of MeCN. After the addition of EtsN (13.8 mL, 99.0 mmol, 2.00 eq.), the for 4 days at 80 °C. The reaction progress was monitored by 1 H NMR spectroscopy. The solvent was then removed under vacuum, and the residue was extracted with hot n-hexane (150 mL). The solution was stored overnight at -20 °C, yielding the product Br(PNsltBu) as a crystalline yellow solid. The product Br(PNsltBu) was subsequently dried under vacuum at 80 °C for 24 hours. Yield: 87% (15.1 g, 42.9 mmol).
[0163] 4-carboxy-N-(1,3-diisopropyl-l,3-dihydro-2H-benzo[d]imidazol-2-ylidene)-2,6-dimethylbenzenaminium tetrafluoroborate ([HO2C(P"NBiPr)H] [BF4])
[0164] In a Schlenk flask, Br(P"NBiPr) (2.18 g, 5.44 mmol, 1.00 eq.) was dissolved in 25 mL of THF and cooled to -78 °C. Then, a 1.6 M solution of n-butyllithium in n-hexane (3.40 mL, 5.44 mmol, 1.00 eq.) was slowly added dropwise and stirred for 1 h at this temperature. Subsequently, CO2 was added using a Teflon cannula. was passed through the reaction solution for 15 min and then stirred for 1 h at room temperature. All volatiles were removed in vacuo, and the residue was treated with 10 mL of water. A 5.5 M solution of tetrafluoroboric acid in water (2.00 mL, 10.9 mmol, 2.00 eq.) was then slowly added and stirred for 15 min. The product [HO2C(P"NBiPr)H][BF4] precipitated as a white solid. This was filtered, washed first with water and then with Et2© (3 x 20 mL). Finally, [HO2C(P"NBiPr)H][BF4] was dried in vacuo at 120 °C for 24 h and obtained as a white solid in 84% yield (2.10 g, 4.6 mmol).
[0165] 4-(( 1,3-diisopropyl-1,3-dihydro-2H-benzo[d]imidazol-2-ylidene)amino) -3,5-dimethylbenzoic acid (HO2C(P"NBiPr))
[0166] [HO2C(P"NBiPr)H] [BF4] (340 mg, 0.75 mmol) and sodium tert-butoxide (72.0 mg, 0.75 mmol) were placed in a Schlenk flask. After the addition of 5 mL of tetrahydrofuran, the reaction solution was stirred for 1 h at room temperature. The suspension was then filtered, and the solution was covered with n-hexane. and stored overnight. The crystalline compound
[0167] HO2C(P"NBiPr) was washed with the mother liquor and dried in vacuum at
[0168] Dried overnight at room temperature. Yield: 93% (256 mg, 0.70 mmol).
[0169] 4-carboxy-N-(1,3-di-tert-butylimidazolidin-2-ylidene)benzenaminium tetrafluoroborate
[0170] ([HO2C(PNsltBu)H] [BF4]) In a Schlenk flask, Br(PNsltBu) (5.64 g, 16.0 mmol, 1.00 eq.) was dissolved in 50 mL of THF and cooled to -78 °C. A 1.6 M solution of n-butyllithium in n-hexane (10.0 mL, 16.0 mmol, 1.00 eq.) was then slowly added dropwise and stirred at this temperature for 1 h. Subsequently, CO2 was passed through the reaction solution using a Teflon cannula for 15 min. and then stirred for 1 h at room temperature. All volatiles were removed in vacuo, and the residue was treated with 25 mL of water. A 5.5 M solution of tetrafluoroboric acid in water (5.90 mL, 32.0 mmol, 2.00 eq.) was then slowly added and stirred for 15 min. The product [HO2C(PNsltBu)H][BF4] precipitated as a white solid. This was filtered, washed first with water and then with Et2© (3 x 50 mL). Finally, [HC>2C(PNsltBu)H][BF4] was dried in vacuo at 120 °C for 24 h and obtained as a white solid in 90% yield (5.90 g, 14.6 mmol).
[0171] 4-((1,3-di-tert-butylimidazolidin-2-ylidene)amino)benzoic acid (HC^CfPNsitBu)) [HO2C(PNsltBu)H][BF4] (304 mg, 0.75 mmol) and sodium tert-butoxide (72.0 mg, 0.75 mmol) were placed in a Schlenk flask. After the addition of 5 mL of tetrahydrofuran, the reaction solution was stirred for 1 h at room temperature. The suspension was filtered, the solution was layered with n-hexane, and stored overnight. The crystalline compound (HChCfPNsItBu) was washed with the mother liquor and dried overnight under vacuum at room temperature. Yield: 92% (219 mg, 0.69 mmol).
[0172] Bismuth(III)-(4-((1,3-di-tert-butylimidazolidin-2-ylidene)ammonio)benzoate)tetrafluoroborate)3 ([Bi(O2C(PNsltBu)H)3][BF4]3 / Bi(O2C(PNsltBu))3; catalyst according to Example 4)
[0173] 15 , and compound [H02C(PNsltBu)H][BF4] (243 mg, 0.60 mmol) at 80 °C. The solid was then washed with 3 x 5 mL of toluene and dried overnight in vacuo at 120 °C. Yield: 95% (270 mg, 0.19 mmol).
[0174] To prepare the catalyst Bi(O2C(PNsltBu))s, the amount required for catalysis was prepared by deprotonation of [Bi(O2C(PNsltBu)H)3][BF4]3 with a potassium tert-butoxide standard solution in tetrahydrofuran and used directly for the urethane reaction.
[0175] Bismuth 4-butylbenzoate (Bi(bbz)3; catalyst according to comparative example cf. 1)
[0176] Compound Bi(bbz)3 was prepared according to a modified literature procedure (PC Andrews, GB Deacon, PC Junk, I. Kumar and M. Silberstein, Dalton Trans., 2006, 4852-4858) using BiPhs (440 mg, 1.00 mmol) and 4-butylbenzoic acid (540 mg, 3.00 mmol) in quantitative Yield produced. II. Determination of catalyst activity
[0177] The catalyst activity of the individual working and comparative examples can be seen in Table 1 below. The catalyst activity was tested using a reaction in which a compound containing a urethane group was formed. The reactant used was 11 mmol of 2-ethylhexyl-(6-isocyanatohexyl)-carbamate (commercially available as Desmodur LD (3.3 mL)) with 11 mmol of n-butanol (1 mL). The reaction was carried out at room temperature in the presence of a solvent (2 mL xylene) and the catalysts listed in Table 1 (with a catalyst content of 0.05 mol% based on the amount of bismuth).
[0178] The isocyanate reduction and thus the formation of a urethane group are investigated using horizontal ATR-IR spectroscopy. For this purpose, 0.05 mL of the reaction solution is taken at defined intervals and directly analyzed. Based on the relative intensity decrease of the asymmetric isocyanate stretching vibration at 2250–2285 cm' 1 The conversion is determined. The initial content of free isocyanate was determined at room temperature in the reaction solution in the absence of a catalyst. All IR spectra were normalized to the bands of the symmetric and asymmetric stretching vibrations of the CFh groups (3000 - 2870 cm' 1 ).
[0179] The catalysts used in Table 1 are as follows:
[0180] Comparative example 1 (cf. 1): Bi(bbz)3
[0181] Comparative example 2 (cf. 2): Br(PNsltBu)
[0182] Comparative example 3 (cf. 3): Bi(bbz)3+ 3 eq. Br(PNsltBu)
[0183] Example 4 (Ex. 4): Bi(O2C(PNsl / Bu))3
[0184] Comparative example 5 (cf. 5): without catalyst
[0185] Table 1
[0186] As can be seen from Table 1, neither the Bi carboxylate with the ligand bbz (cf. 1) nor the halo-imine Br(PNsltBu) (cf. 2) show increased activity in the urethane reaction compared to the uncatalyzed reaction. The mixture consisting of Bi(bbz)3 and 3 eq. Br(PNsltBu) (cf. 3) also shows only a slight increase in the catalytic activity of the urethane reaction compared to the uncatalyzed reaction. Surprisingly, the compound Bi(O2C(PNsltBu))3 is just as inactive during the first 10 minutes of catalysis as the mixture consisting of Bi(bbz)3 and 3 eq. Br(PNsltBu) (cf. 3). However, after this inhibition phase, a remarkable increase in catalytic activity is observed, reaching a conversion of 90% after 60 min.
Claims
Claims Ligand according to the general formula (I) in which the variables are defined as follows: A is N or (NH) + (X)-, B is CH2, CH, CR 5 or CR 5 H, D is CH2, CH, CR 6 or CR 6 H, E is H or alkali, R 1 is H or Ci-Cio-alkyl, R 2 is H or Ci-Cio-alkyl, R 3 is H or Ci-Cio-alkyl, R 4 is H or Ci-Cio-alkyl, R 5 is Ci-C alkyl R 6 is Ci-C alkyl or R 5 and R 6 together form a bridge with four carbon atoms, where B, D, R 5 and R 6 together they can form a benzene fragment, which may optionally combine with a residue R 7 at least monosubstituted, R 7 is Ci-C alkyl X is BF4, OH or halogen, where A (NH) + (X)' is, B CH2, CH, CR 5 or CR 5 H is, D CH2, CH, CR 6 or CR 6 H is, EH is, R 1 C2-C4 alkyl is, R 2 C2-C4 alkyl is, R 3 H or methyl is R 4 H or methyl is R 5 and R 6 together form a bridge with four carbon atoms, provided that B and D are not CH2 or CH, where B, D, R 5 and R 6 together preferably form an unsubstituted benzene fragment, X BF4 is.
2. Ligand according to claim 1, characterized in that i) B and D and optionally R 5 and R 6 each have the same definition, where B, D, R 5 and R 6 together, if necessary, form a benzene fragment, which is preferably unsubstituted, and / or ii) R 1 and R 2each have the same definition, and / or ill) R 3 and R 4 each have the same definition, and / or iv) alkali is equal to sodium or potassium, preferably sodium, provided that E is equal to alkali, and / or v) halogen is equal to chlorine or bromine, provided that X is equal to halogen.
3. Ligand according to claim 1 or 2, characterized in that the ligand is 4-carboxy-N-(1,3-diisopropyl-1,3-dihydro-2H-benzo[d]imidazol-2-ylidene)-2,6-dimethylbenzenaminium tetrafluoroborate or 4-carboxy-N-(1,3-di-tert-butylimidazolidin-2-ylidene)benzenaminium tetrafluoroborate.
4. Bismuth-containing catalyst according to general formula (II) in which the variables are defined as follows: A is N or (NH) + (X)-, B is CH2, CH, CR 5 or CR 5 H, D is CH2, CH, CR 6 or CR 6 H, R 1 is H or Ci-Cio-alkyl, R2 is H or Ci-Cio-alkyl, R 3 is H or Ci-Cio-alkyl, R 4 is H or Ci-Cio-alkyl, R 5 is Ci-C alkyl R 6 is Ci-C alkyl or R 5 and R 6 together form a bridge with four carbon atoms, where B, D, R 5 and R 6 together they can form a benzene fragment, which may optionally combine with a residue R 7 at least monosubstituted, R 7 is Ci-C alkyl X is BF4, OH or halogen, where in each of the three ligands of the bismuth-containing catalyst the respective variables can be defined independently of the other ligands or all three ligands can be defined the same way.
5. Bismuth-containing catalyst according to claim 4, characterized in that all three ligands of the bismuth-containing catalyst are defined identically.
6. Bismuth-containing catalyst according to claim 4 or 5, characterized in that i) B and D and optionally R 5 and R 6 each have the same definition, where B, D, R 5 and R 6 together, if necessary, form a benzene fragment, which is preferably unsubstituted, and / or ii) R 1 and R 2 each have the same definition, and / or ill) R 3 and R 4 each have the same definition, and / or iv) halogen is equal to chlorine or bromine, provided that X is equal to halogen.
7. Bismuth-containing catalyst according to one of claims 4 to 6, characterized in that A (NH) + (X)- is B CH2, CH, CR 5 or CR 5 H is D CH2, CH, CR 6 or CR 6 H is R 1 C2-C4 alkyl is, R 2 C2-C4 alkyl is, R 3 H or methyl is R 4H or methyl is R 5 and R 6 together form a bridge with four carbon atoms, provided that B and D are not CH2 or CH, where B, D, R 5 and R 6 together preferably form an unsubstituted benzene fragment, X BF4 is a bismuth-containing catalyst according to any one of claims 4 to 7, characterized in that the bismuth-containing catalyst is bismuth(III)-(4-((1,3-di-tert-butylimidazolidin-2-ylidene)ammonio)benzoate)tetrafluoroborate)3 ([Bi(O2C(PNsltBu)H)3][BF4]3). Precursor of a ligand according to general formula (III) in which the variables are defined as follows: A is N or (NH) + (X)-, B is CH2, CH, CR 5 or CR 5 H, D is CH2, CH, CR 6 or CR 6 H, R 1 is H or Ci-Cio-alkyl, R 2 is H or Ci-Cio-alkyl, R 3is H or Ci-Cio-alkyl, R 4 is H or Ci-Cio-alkyl, R 5 is Ci-C alkyl R 6 is Ci-C alkyl or R 5 and R 6 together form a bridge with four carbon atoms, where B, D, R 5 and R 6 together they can form a benzene fragment, which may optionally combine with a residue R 7 at least monosubstituted, R 7 is Ci-C alkyl X is BF4, OH or halogen Y is halogen, preferably Br. A process for producing a ligand according to one of claims 1 to 3, characterized in that the ligand according to general formula (I) is prepared from the corresponding precursor of a ligand of general formula (III) according to Claim 10 is obtained by carboxylation of this precursor in the presence of a catalyst.
11. Process for the preparation of a bismuth-containing catalyst of general formula (II) according to any one of claims 4 to 8, characterized in that i) at least one compound of general formula (I) according to any one of claims 1 to 4 is reacted with ii) at least one bismuth-containing compound selected from Bi2O3, bismuth carbonate, bismuth hydrogen carbonate, bismuth halide, bismuth carboxylate, Bi(C6-Ci4-aryl)3, Bi(Ci-Ci2-alkyl)3 or metallic bismuth.
12. Method according to claim 11, characterized in that the bismuth-containing compound is selected from Bi2O3, BiCI3, Bi(CeH5)3 or metallic bismuth.
13. A process according to claim 11 or 12, characterized in that i) the reaction is carried out under a protective atmosphere and / or in the presence of at least one solvent, in particular toluene, acetonitrile or tetrahydrofuran, and / or ii) the reaction is carried out for at least 10 hours and / or at a temperature of at least 100°C, and / or ill) following the reaction, volatile components are removed, the bismuth-containing catalyst is dried under vacuum and / or recrystallization is carried out.
14. Use of at least one bismuth-containing catalyst according to any one of claims 4 to 8 for the production of compounds containing a urethane group.