Heterogeneous catalyst

Abstract

The present invention relates to a heterogeneous catalyst comprising carrier particles having a carrier surface, wherein metal complexes such as salen aluminum complexes and halogen salts are individually immobilized on the carrier surface, and amines may also be immobilized on the carrier surface. The present invention also relates to a method for preparing a cyclic carbonate by reacting an epoxide compound with carbon dioxide in the presence of a heterogeneous catalyst and a halogen compound.

Description

Technical Field

[0001] The present invention relates to a heterogeneous catalyst comprising carrier particles having a carrier surface, on which a metal complex and a halogen salt are immobilized. This heterogeneous catalyst is particularly suitable for preparing cyclic carbonates starting from epoxides and carbon dioxide.

Background Art

[0002] In the production of fine chemicals and bulk chemicals, the use of carbon dioxide as an inexpensive and readily available C1 source has attracted great interest. One such chemical production route is the synthesis of cyclic carbonates from strained epoxides and CO2. Cyclic carbonate products are used as electrolytes in lithium-ion batteries. Furthermore, they can be used as monomers for polycarbonate synthesis and non-isocyanate polyurethanes, or as synthetic intermediates.

[0003] Various high-pressure methods, such as those described in EP2431363, are known. This published document describes a method carried out at 20 bar in the presence of a tetra(n-butyl)phosphonium bromide catalyst.

[0004] It is desired to carry out this reaction under more ambient pressure conditions. Catalysts suitable for this reaction at low pressure are Lewis base catalysts and halide anions (X -This includes halogen salts as a source of Epoxides.RAFIK RAJJAK SHAIKH et al.: "Catalytic Strategies for the Cycloaddition of Pure Diluted, and Waste CO2 to Epoxides under Ambient Conditions," ACS CATALYSIS, Part B, No. 1, January 5, 2018 (2018-01-05), pp. 419-450, XP055671558, describes various catalysts for the synthesis of cyclic carbonates starting from epoxides and carbon dioxide.This article describes organometallic complexes as Lewis acids that exhibit excellent catalytic performance in the presence of halogen salts, particularly tetra-n-butylammonium bromide (TBAB).An example mentioned in this article is aminotrisphenolate metal complexes.Metals that may be mentioned are aluminum, gallium, indium, iron, cobalt, nickel, zinc, titanium, and / or bismuth. Furthermore, it has been explained that the oxodimers of substituted salen-aluminum complexes may be Lewis acids.

[0005] US2021 / 0355094 describes a catalyst containing an ethylenediamino-bridged tetra(phenolate) rare-earth-zinc heterodimetallic compound as the Lewis acid. The reaction of the epoxide with carbon dioxide is carried out in the presence of this compound and tetra-n-butylammonium bromide (TBAB).

[0006] ChemCatChem 2021, 13, 4099-4110 describes gallium organic complexes, such as gallium aminotrisphenolate compounds, that catalyze the synthesis of cyclic carbonates in the presence of tetrabutylammonium iodide (TBAI) or tetrabutylammonium bromide (TBAB), starting from epoxides and carbon dioxide.

[0007] Many of the reported catalyst systems have been tested for this reaction in a homogeneous reaction environment. For commercial applications, it is advantageous to carry out the reaction in the presence of heterogeneous catalysts. This simplifies, for example, the separation of the catalyst from the formed cyclic carbonate.

[0008] WO2009 / 109765 describes a method for preparing cyclic carbonate compounds from carbon dioxide and epoxide compounds using a heterogeneous catalytic system containing oxodimers of substituted salen-aluminum complexes. This catalytic system requires the presence of an ammonium halogen salt, such as tetra-n-butylammonium bromide (TBAB), to be catalytically active. However, systems containing such dissolved ammonium salts are not advantageous due to problems with this compound in downstream processing units. This patent appears to solve this problem by immobilizing the salen-aluminum complex on a silica support via a diethylammonium (propyl)ethyl substituent on the phenyl group of the salen-aluminum complex. The presence of this diethylammonium (propyl)ethyl group not only immobilizes the complex on the silica support but also functions as an ammonium salt. However, tetra-n-butylammonium bromide (TBAB) needs to be added further to activate the catalyst. A drawback is that tetra-n-butylammonium bromide is known to leach from the supported catalytic system. [Prior art documents] [Patent Documents]

[0009] [Patent Document 1] European Patent No. 2431363 [Patent Document 2] U.S. Patent Application Publication No. 2021 / 0355094 [Patent Document 3] International Publication No. 2009 / 109765 [Non-patent literature]

[0010] [Non-Patent Document 1] RAFIK RAJJAK SHAIKH et al.: "Catalytic Strategies for the Cycloaddition of Pure Diluted, and Waste CO2 to Epoxides under Ambient Conditions," ACS CATALYSIS, Part B, No. 1, January 5, 2018 (2018-01-05), pp. 419-450. [Non-Patent Document 2] ChemCatChem 2021, 13, 4099~4110 [Overview of the Initiative] [Problems that the invention aims to solve]

[0011] The object of the present invention is to provide a supported catalyst system suitable for the synthesis of cyclic carbonates starting from epoxides and carbon dioxide, without leaching halogen salts such as tetra-n-butylammonium bromide. [Means for solving the problem]

[0012] This problem is solved by the following heterogeneous catalyst: A heterogeneous catalyst comprising carrier particles having a carrier surface, wherein a metal complex and a halogen salt are immobilized on the carrier surface, and the metal complex and halogen salt are each individually immobilized on the carrier surface.

[0013] The present applicants have found that the heterogeneous catalyst according to the present invention can be advantageously used as a catalyst or as part of a catalyst in a chemical process in the presence of an organic halogen compound and in the absence of an immobilized halogen ammonium salt. The presence of this halogen compound improves the activity of the catalyst, for example when the catalyst is reused in a subsequent batch operation or semi-batch operation for preparing a cyclic carbonate. This makes it possible to use this catalyst in a chemical process in which a metal complex has catalyzed and there is no immobilized halogen ammonium salt. When this catalyst is used in the presence of an organic halogen compound, the presence of an unnecessary non-immobilized halogen ammonium salt becomes unnecessary. In particular, it has been found that the heterogeneous catalyst of the present invention can be used in a method for preparing a cyclic carbonate by reacting an epoxide compound with carbon dioxide without leaching of the halogen ammonium salt.

[0014] Furthermore, due to the fact that the metal complex and the halogen salt are individually immobilized, it becomes possible to affect the relative presence of the halogen salt with respect to the metal complex in the catalyst.

[0015] Preferably, the amine is also individually immobilized on the support surface adjacent to the halogen salt and the metal complex. When the amine is also immobilized, the heterogeneous catalyst has been found to effectively bind to carbon dioxide. This allows a gas containing carbon dioxide, such as flue gas or flue gas from a cement kiln, to be brought into direct contact with the catalyst. The amine is preferably a tertiary amine and has the general formula R 1 R 2 R 3 N (where R 1 is an anchor group for covalently bonding a tertiary amine to the support surface.). R 2 and R 3 can be the same or different organic groups and are preferably the same or different alkyl groups having 1 to 20 carbon atoms, preferably 1 to 6 carbon atoms. R 2 and R 3 can also be part of a ring structure forming a 5-membered or 6-membered ring. R 2 or R3 R may be an aminoalkyl group. 2 and R 3 Examples of compounds in which R is part of a ring structure include morpholine, piperidine, and pyrrolidine compounds. More preferably, 2 and R 3 R is the same alkyl group, for example, the same methyl group or ethyl group. 1 The group may be an alkyl(trialkoxy)silane anchor group, where the alkyl group preferably has 2 to 6 carbon atoms and the alkoxy group preferably has 1 to 3 carbon atoms. 1 These are alkyltrichlorosilane, propyl(alkyl)dichlorosilane, and propyl(dialkyl)chlorosilane anchor groups, where the alkyl group may have 2 to 6 carbon atoms. Examples of these groups include propyl(trimethoxy)silane, propyl(triethoxy)silane, propyl(methyl)dichlorosilane, propyl(dimethyl)chlorosilane, and propyltrichlorosilane. 1 This may be styryl(trialkyl)silane, propylbis(methylallyl)silanepropyl, tris(methylallyl)silane, propyl phosphate, propyl(dialkyl)phosphonate, and alkyl-1,1-bisphosphonic acid, where the alkyl group may have 1 to 6 carbon atoms.

[0016] The halogen salts are preferably ammonium halogen salts or phosphonium halogen salts. The choice of halogen also determines the choice of other halogen compounds used as part of the catalytic system, as it is desirable that they be the same. This halogen is also called the catalytic halogen. Preferred halogen salts are iodide salts and bromide salts. The immobilized iodide salt is preferably a phosphonium iodide salt, more preferably a quaternary ammonium iodide salt. The immobilized bromide salt is preferably a phosphonium bromide salt, more preferably a quaternary ammonium bromide salt. Quaternary ammonium iodide salts and quaternary ammonium bromide salts have the general formula R 4 R 5 R 6 R 7NX (wherein X is a bromide or iodide anion, R 4 R is an anchor group, 5 , R 6 and R 7 These may have the same or different alkyl or aryl groups, preferably having 1 to 20 carbon atoms. 5 and R 6 It may be part of a ring structure that forms a 5-membered ring or a 6-membered ring. 5 and R 6 Examples of compounds in which R is part of a ring structure include morpholine, piperidine, and pyrrolidine compounds. Preferred R 5 , R 6 and R 7 The group is an alkyl group having 1 to 20 carbon atoms, more preferably 3 to 12 carbon atoms, such as propyl, n-butyl, isobutyl, tert-butyl, n-pentyl, neopentyl, and isopentyl.

[0017] Anchor base R 4 is the anchor base R 1 This is the same as the explanation given earlier.

[0018] Metal complexes, alkylated amines, and halogen salts can be immobilized on a carrier surface by steric capture, electrostatic bonding, and / or covalent bonding. Preferably, immobilization is carried out by covalent bonding using anchor groups.

[0019] For covalent bonding to occur, the solid carrier must contain, or be derivatized to contain, reactive functional groups that help to covalently bond the anchor compound to its surface. Examples of suitable reactive functional groups are titanol (Ti-OH), silanol, and aluminol (Al-OH). Materials having such functional groups include, for example, silicon dioxide carriers containing reactive silanol groups, alumina carriers containing reactive aluminol groups, amorphous silica-alumina carriers having both silanol and aluminol groups, and sol-gel materials. Other possible carrier particles may be polyacrylamide carriers, polystyrene carriers, and polyethylene glycol carriers.

[0020] Preferred carrier particles are titanium dioxide, silica, alumina, and / or silica-alumina particles. The silanol groups present on the surface of silica or silica-alumina particles and / or the aluminol groups present on the surface of alumina or silica-alumina particles, or the titanol present on the surface of titanium dioxide particles, are preferably covalently bonded.

[0021] Catalyst particles can be relatively large when used as part of a packed bed in a reactor. Inert particles may be present in such a bed. Preferably, the heterogeneous catalyst exists as a suspension in a liquid reaction mixture. In this case, the support exists as a powder that is small enough to form a high active catalyst surface area per unit weight of the support, and large enough to be easily separated from the cyclic carbonate inside or outside the reactor. Preferably, the supported powder particles have a particle size of at least 90% by weight of all particles being larger than 10 μm and smaller than 2000 μm. Particle size is measured with Malvern® Mastersizer® 2000.

[0022] Metal complexes, halogen salts, and optional tertiary amines are as follows: S-(R 1 -(R 2 R 3 N)) k S-(R 4 -(R 5 R 6 R 7 NX)) m S-(R 8 - Metal complex) n [In the formula, S is the carrier surface, Tertiary amines are R 1 R 2 R 3 N (wherein, R 1 R is an anchor group that covalently bonds a tertiary amine to the support surface S, 2 and R 3R is an identical or different alkyl group having 1 to 20 carbon atoms. 2 and R 3 is part of a ring structure that forms a 5-membered ring or a 6-membered ring, or R 2 or R 3 It is an aminoalkyl group. Quaternary ammonium halogen salts are R 4 R 5 R 6 R 7 NX (wherein X is a bromide or iodide anion, R 4 R is an anchor group that covalently bonds a quaternary ammonium halogen salt to the support surface S, 5 , R 6 and R 7 These are identical or different alkyl groups having 1 to 20 carbon atoms. R 8 This is an anchor group that covalently bonds the metal complex to the support surface S. k:m:n represents the molar ratio of the amine, halogen salt, and metal complex individually immobilized on the support surface S. As shown, heterogeneous catalysts can be individually and appropriately immobilized on the support surface.

[0023] The molar ratio of the halogen salt to the metal complex is appropriately 1:1 or greater. In the above equation, m is equal to or greater than n. If the amine is not immobilized, k is equal to zero.

[0024] When the metal complex is, for example, an aluminum complex as described in more detail below, the molar ratio of k:m is preferably 3:1 to 8:1. The molar ratio of n:k is preferably 1:3 to 1:10, and more preferably 1:3 to 1:5.

[0025] As will be explained in more detail, when the metal complex is a gallium complex, the molar ratio of k:m is preferably less than 1:4, where k may be equal to 0.

[0026] If the carrier surface has silanol groups present on the surface S of silica or silica-alumina particles and / or aluminol groups present on the surface S of alumina or silica-alumina particles, R 1 , R 4 and R 8 Preferably, these are the same or different alkyl(trialkoxy)silane anchor groups and / or alkyltrichlorosilane anchor groups.

[0027] The metals that make up the metal complex may be one or more selected from the group consisting of aluminum, gallium, indium, iron, cobalt, nickel, zinc, titanium, and / or bismuth. Rare earth metal complexes, such as the polydentate coordination of N-methylethylenediamine-bridged tris(phenolate) ligands to Y, Sm, Nd, and La, as described in ACS Sustainable Chem.Eng.2020, 8, 13185-13194, can also be used.

[0028] US2021 / 0355094 describes a catalyst containing an ethylenediamino-bridged tetra(phenolate) rare-earth-zinc heterodimetallic compound as the Lewis acid. The reaction of the epoxide with carbon dioxide is carried out in the presence of this compound and tetra-n-butylammonium bromide (TBAB).

[0029] The metal complex may be any catalytically active complex activated by an ammonium halogen salt, preferably tetra-n-butylammonium bromide (TBAB). More preferably, any metal complex known to catalyze carbon dioxide-involved reactions. Preferably, the metal complex is an aminotrisphenolate metal complex. Examples include the aminotrisphenolate aluminum complexes described in J.Am.Chem.Soc.2013, 135, 1228-1231, Chem.Eur.J.2014, 20, 2264-2275, and Chem.Sus.Chem.2017, 10, 1274-1282.

[0030] Possible aminotrisphenolate iron complexes are described in Inorg. Chem. 2012, 51, 20, 10639-10649.

[0031] Preferred metal complexes are aminotrisphenolate gallium complexes, such as those described in ChemCatChem 2021, 13, 4099-4110. Good catalytic activity has been found to be achieved both when the tertiary amine is individually immobilized and when it is not individually immobilized. Preferably, the molar ratio of individually immobilized halogen salt to individually immobilized metal complex is appropriately 1:1, and more preferably higher than 3:1, for this type of catalyst.

[0032] Vanadium complexes that may be active in this reaction in the presence of tert-butyl iodide are described in ChemCatChem 2012, 4, 1190-1196.

[0033] Another preferred metal complex is a salen-metal complex or its oxodimer, more preferably a salen-aluminum complex or its oxodimer, and most preferably a salen-aluminum complex. In this type of catalyst, it is preferable that the amine is immobilized separately next to the halogen salt and the metal complex. The salen-aluminum complex and / or its oxodimer may be the complex described in WO2009 / 109765 above. The salen-aluminum complex is preferably immobilized using an anchor group. This anchor group may be substituted with one of the phenyl groups, which are a typical part of these salen-aluminum complexes, as disclosed in WO2009 / 109765, or with a bridging group that links two nitrogen atoms of the salen-aluminum complex. Preferably, the anchor group contains a halogen, preferably a quaternary ammonium nitrogen paired with the halogen of the catalyst system. An example of such an anchor group is the diethylammonium(propyl)ethyl group described in WO2009 / 109765 above. This is advantageous because the quaternary ammonium nitrogen ion paired with the halogen in the catalyst system functions as a co-catalyst for the heterogeneous catalyst of the present invention.

[0034] The problem with the catalyst described in WO2009 / 109765 is that the supported salen-aluminum ligand is difficult to prepare and requires at least nine synthesis steps. Some of these steps have low yields, resulting in an overall yield of less than 10%, and the synthesis method uses large amounts of solvent. The applicants have found a complex that can be prepared in a much simpler manner and in higher yields. This preferred salen-aluminum complex and / or its oxodimer is an optionally substituted salen-aluminum complex or its oxodimer having a pyridinium bridging group. The quaternary nitrogen ion of the pyridinium bridging group serves as a cocatalyst in the catalyst system and as an anchor group R for immobilization on the support surface. 8 It functions as a means of connecting.

[0035] The pyridinium bridging group may be a 2-pyridinium bridging group, and preferably a 3-pyridinium bridging group that enables the bonding of an anchor group. Optionally substituted salenaluminum ligands having a salenaluminum ligand with a 3-pyridinium bridging group are given by the following general formula:

[0036] [ka] (In the formula, B is a halogen, an alkoxy group, or an alkyl group. The phenyl group of the salen aluminum ligand is optionally substituted, R 8 (where is an anchor group and X is a halogen anion.) The phenyl group, which can be represented as , may be substituted at the 3-position. The alkoxy group B may be a methoxy group, an ethoxy group, and / or an isopropoxy group. The alkyl group B may have 1 to 5 carbon atoms, such as a methyl group or an ethyl group. B may also be a chloride group, a bromide group, or an iodide group. The choice of B may depend on the availability of the starting aluminum compound when synthesizing the complex. For this reason, a chloride group is preferred for B.

[0037] Anion X may be a halogen in the catalyst system, which may be an iodide anion or a bromide anion.

[0038] The phenyl group in the above formula may be substituted with a halogen, an optionally substituted C1-20 alkyl group, an optionally substituted C5-20 aryl group, an optionally substituted C3-20 heterocyclyl group, an ether group, an ammonium group, or a nitro group. An example is described in EP2146977. Preferably, the phenyl group is substituted with a butyl group, and more preferably with a tert-butyl group.

[0039] Anchor base R 8 R 1 and R 4The explanation above may be the same as for this.

[0040] Heterogeneous catalysts are composed of one of the following complexes exhibiting different anchor groups R and different groups B: [Al(3,4-Py-sulfen(N-propyl(trimethoxy)silane))(Cl)]Br, [Al(3,4-Py-sulfen(N-propyl(triethoxy)silane))(Cl)]Br, [Al(3,4-Py-sulfen(N-propyl(triethoxy)silane))(OEt)]Br, [Al(3,4-Py-sulfen(N-propyl(triethoxy)silane))(Cl)]I, [Al(3,4-Py-sulfen(N-propyl(diethoxyphosphonate)(Cl)]Br, [Al(3,4-Py-sulfen(N-propyl(phosphate)(Cl)]Br, [Al(3,4-Py-sulfen(N-butyl(diethylphosphonate)(OEt)]Br, and [Al(3,4-Py-sulfen(N-pentyl(phosphate)(Cl)]Br, [Al(3,4-Py-sulfen(N-propyl(trimethoxy)silane))(Et)]Br, [Al(3,4-Py-sulfen(N-propyl(trimethoxy)silane))(OEt)]Br, Here, in the above complex, a substituent is optionally present at the 3-position of the phenyl group in the sulfen structure. Furthermore, in the above description, Et is ethyl and OEt is ethoxy.

[0041] Heterogeneous catalysts, comprising immobilized optionally substituted salen-aluminum complexes having pyridinium crosslinking groups, can be prepared by the following method.

[0042] A method for preparing an optionally substituted salen aluminum complex, starting from a corresponding optionally substituted salen nickel or zinc complex having a 3-pyridine crosslinking group, comprising the following steps: (a) A step of demetallizing the corresponding substituted nickel-salen or zinc complex to obtain a demetallized salen ligand, (b) A step of contacting the demetallated salen ligand from step (a) with an aluminum compound to obtain an optionally substituted salen-aluminum complex having a 3-pyridine bridge, and (c) A optionally substituted salen aluminum complex having a 3-pyridine bridge is subjected to alkylation with an anchor precursor compound to obtain a pyridinium bridge group and an anchor group R bonded to the quaternary nitrogen ion of the pyridinium bridge group. 8 A step to obtain a corresponding alkylated optionally substituted salen aluminum complex having, and (d) A step of immobilizing the alkylated optionally substituted salen aluminum complex obtained in step (c) onto the surface of a support.

[0043] Corresponding starting substituted salen nickel or zinc complexes having a 3-pyridine bridging group can be obtained as described in Catal. Sci. Technol., 2014, 4, 1615 and ChemCatChem 2011, 3, 831-834. This method is particularly suitable for preparing complexes having a 3-pyridine bridging group and the corresponding complexes having a 3-pyridinium bridging group.

[0044] In step (a), the corresponding substituted salen nickel or zinc complex is demetallated to obtain a demetallated salen ligand. Demetallation can be carried out by known demetallation methods, such as those described in Organometallics 2002, 21, 14, 2950-2957. Demetallation is adequately carried out by anhydrous demetallation in the presence of imidazole in acetonitrile, toluene, tetrahydrofuran (THF), or methyltetrahydrofuran. This step can be carried out in high yield. Tetrahydrofuran (THF) or methyltetrahydrofuran is preferred, especially when preparing large quantities of the complex.

[0045] Figure 1 shows an example of a demetallated salen ligand that yields a complex after metallization according to the present invention.

[0046] In step (b), the demetallated salen ligand from step (a) is brought into contact with an aluminum compound. This aluminum compound constitutes a precursor of group B as used herein to describe a preferred complex. If B is a chloride, the aluminum compound is suitable to be diethylaluminum chloride (Al(Et)2Cl) or aluminum diethoxycyclolide (Al(OEt)2Cl). If B is an alkoxy group such as ethoxy, the aluminum compound is preferably triethoxyaluminum. If B is an alkyl group, the aluminum compound is preferably one in which the alkyl group has 1 to 5 carbon atoms, such as trialkylaluminum compounds such as trimethylaluminum and triethylaluminum.

[0047] Preferably, when this method is carried out on a large scale and reagent contact is enhanced, the aluminum compound is gradually added in step (b) to the demetallated salen ligand, which is dissolved or dispersed as a slurry in a suitable solvent. It has been found that if the aluminum compound is not added gradually, the reactants solidify and the reagents cannot be effectively mixed. The demetallated salen ligand is preferably dissolved or dispersed as a slurry in a suitable solvent, such as toluene or THF (tetrahydrofuran). The time for gradual addition is preferably more than 1 hour, and more preferably more than 1.5 hours. Preferably, the addition is continued for no more than 3 hours. The temperature is preferably 20 to 90°C, more preferably 50 to 80°C. To reduce the solubility of the resulting optionally substituted salen-aluminum complex, a C5 to C10 hydrocarbon alkane solvent, preferably heptane, is added. The solidified complex can be separated from the solvent by filtration.

[0048] The corresponding optionally substituted salen aluminum complex having a pyridinium bridging group is prepared in step (b). In step (c), the optionally substituted salen aluminum complex having a pyridine bridging obtained in step (b) is subjected to an alkylation reaction to obtain the corresponding optionally substituted salen aluminum complex having a pyridinium bridging group. Alkylation is carried out by atomizing the optionally substituted salen aluminum complex having a pyridine bridging in a suitable solvent with halogen-R 8 Compounds, preferably bromide compounds, Br-R 8 (In the formula, R 8 This is done appropriately by contacting the above-mentioned anchor group. Suitable solvents are tetrahydrofuran (THF), dimethylformamide (DMF), NMP, n-butylpyrrolidone, sulfolane, dimethyl sulfoxide (DMSO), or a mixture of dimethyl sulfoxide (DMSO) and acetonitrile, or a mixture of dimethyl sulfoxide (DMSO) and sulfolane, or a mixture of dimethyl sulfoxide (DMSO) and n-butylpyrrolidone.

[0049] It was found to be advantageous to start alkylation from an optionally substituted salen-aluminum complex rather than alkylating an optionally substituted starting salen-zinc complex having a pyridine crosslinking group. It was found that it is not possible to subject the zinc complex to alkylation using the bromide compound Br-R. By starting with the aluminum complex, alkylation with Br-R becomes possible, and the complex of the present invention in which X is a bromide ion can be prepared.

[0050] In step (d), the alkylated, optionally substituted salen aluminum complex obtained in step (c) is immobilized on the support surface. In step (d), halogen salts and optionally amines are also immobilized on the support surface. This can be done by contacting the support surface with these individual compounds simultaneously, preferably by the anchor groups of these compounds forming covalent bonds with the reactive functional groups of the support surface. Alternatively, the heterogeneous catalyst can also be prepared by contacting the support surface with the salen aluminum complex and a preferred tertiary amine simultaneously. The resulting heterogeneous precursor catalyst can then be contacted with halogen compounds, where some of the immobilized tertiary amine reacts to form a preferred quaternary ammonium halogen salt. Activation of this heterogeneous precursor catalyst can be performed when preparing the heterogeneous catalyst or when the catalyst is to be used at the site of the method. This method for obtaining a heterogeneous catalyst has the advantage that it does not require the halogen salts to be immobilized individually.

[0051] Accordingly, the present invention also relates to heterogeneous precursor catalysts comprising carrier particles having a carrier surface, wherein a salen aluminum complex and / or its oxodimer is immobilized on the carrier surface, and a tertiary alkylamine is immobilized on the carrier surface. Preferably, the molar ratio of the tertiary amine to the atomic aluminum of the salen aluminum complex and / or its oxodimer is greater than 3:1, and preferably greater than 4:1. This results in the presence of a large amount of immobilized tertiary amine, some of which reacts with preferred quaternary ammonium halogen salts during catalyst activation. Preferably, the activation is carried out to obtain a heterogeneous catalyst in which the molar ratio of the amine, excluding an optional quaternary ammonium as part of the salen aluminum complex, to the total quaternary ammonium is 3:1 to 8:1.

[0052] The present invention also relates to a method for activating the above-mentioned heterogeneous precursor catalyst by contacting it with a halogen compound, preferably an iodide compound, and more preferably a bromide compound. The halogen in the halogen compound is the halogen of the catalytic system. Examples of suitable halogen compounds include halogen compounds used in the method of preparing cyclic carbonates by reacting epoxide compounds with carbon dioxide, as described below.

[0053] The heterogeneous catalyst described above according to the present invention includes embodiments in which an alkylated amine and a quaternary ammonium halogen salt are immobilized. The immobilized quaternary ammonium halogen salt acts as a cocatalyst when the catalyst is used in a method for preparing a cyclic carbonate by reacting an epoxide compound with carbon dioxide. In this catalyst, the salen aluminum complex may be any of the above, preferably comprising a quaternary ammonium halogen salt as part of the anchor groups described above. In other embodiments, the quaternary ammonium halogen salt that can act as a cocatalyst is part of the anchor groups that immobilize the salen aluminum complex on the support surface. The immobilized halogen salt may be any of the above, such as a phosphonium halogen salt, preferably a quaternary ammonium halogen salt.

[0054] Therefore, in the preferred heterogeneous catalyst, alkylated amines and quaternary ammonium are immobilized, and the quaternary ammonium can be immobilized as part of an immobilized halogen salt and as part of an immobilized salen-aluminum complex. The molar ratio of individually immobilized amines to individually immobilized quaternary ammonium is preferably 3:1 to 8:1, except for the optional quaternary ammonium as part of the salen-aluminum complex.

[0055] The molar ratio of individually immobilized salen-aluminum complexes, expressed in terms of moles of aluminum, to individually immobilized amines is preferably 1:3 to 1:5. The optimal heterogeneous catalyst has a molar ratio of approximately 1 mole of aluminum, 4 moles of amine, and 1 mole of ammonium in the salen-aluminum complex, excluding an optional quaternary ammonium which is part of the salen-aluminum complex. Such catalysts can be prepared by contacting the immobilized ammonium halogen salt, salen-aluminum complex, and tertiary amine components with a support in approximately equal proportions. The ratio of these compounds on the support surface of the prepared heterogeneous catalyst can be measured by inductively coupled plasma mass spectrometry (ICP-MS).

[0056] Heterogeneous catalysts can be used as a catalyst or as part of a catalyst in copolymerization methods for preparing aliphatic polycarbonates starting from epoxide compounds and carbon dioxide. Another reaction in which heterogeneous catalysts are used is the method of preparing polyesters by ring-opening polymerization of lactone compounds, as described, for example, in WO2012 / 065711.

[0057] Preferably, the heterogeneous catalyst is used as a catalyst or as part of a catalyst in a method for preparing a cyclic carbonate by reacting an epoxide compound with carbon dioxide.

[0058] Therefore, the present invention also covers a method for preparing cyclic carbonates by reacting an epoxide compound with carbon dioxide in the presence of a heterogeneous catalyst.

[0059] Preferably, this method is carried out in the presence of the corresponding halogen compound. The halogen compound may be an aryl halogen compound, and preferably an alkyl halogen compound. The halogen of the halogen compound is the halogen of the catalytic system. The presence of the corresponding halogen compound is beneficial to the activity and stability of the catalyst. It has been found that the reaction rate can be affected by adjusting the content of the corresponding halogen compound when carrying out the method. The halogen compound is not a halogen salt. The amount of the corresponding halogen compound is not necessarily large. Good results were obtained when the corresponding halogen compound was present in an amount of 0.3 to 10 mol%, preferably 0.5 to 3 mol%, relative to the epoxide compound.

[0060] When a bromide salt is immobilized, preferably the bromide compound is present as the corresponding halogen compound. This bromide compound can react in situ with the immobilized tertiary amine to form the desired quaternary ammonium salt. In this method, any immobilized halogen salt that is removed from the support surface for any reason and does not function as a cocatalyst can be replaced with the immobilized quaternary ammonium salt formed in situ. When the amine is not immobilized, such as in the illustrated gallium-based catalyst, it is also advantageous to carry out the method in the presence of the halogen compound. This can be explained by the fact that the halogen compound can restore the deactivated immobilized halogen salt in situ. In this way, the level of the cocatalyst can be maintained at the desired level on the support surface. When a desired bromide salt is used, this method is preferably carried out in the presence of an aryl bromide and / or alkyl bromide. Therefore, reactivation with tetra-n-butylammonium bromide (TBAB), as in the method of WO2009 / 109765, can be omitted. A suitable aryl bromide is benzyl bromide. Because this compound is corrosive to some metals, it may be preferable to carry out processing in a glass or glass-lined processing apparatus. Preferably, less corrosive bromide compounds are used, such as alkyl bromides, such as C3-C10 alkyl bromide compounds, such as propyl bromide, butyl bromide, pentyl bromide, hexyl bromide, heptyl bromide, and octyl bromide. Another suitable group of alkyl bromides is alkyl dibromides, such as 1,2-dibromoethane, 1,3-dibromopropane, 1,4-dibromobutane, 1,5-dibromopentane, and 1,6-dibromohexane.

[0061] The starting epoxide compound preferably has 2 to 8 carbon atoms. Suitable epoxide compounds include ethylene oxide, propylene oxide, butylene oxide, pentene oxide, glycidol, styrene oxide, epichlorohydrin, or fluoroethylene oxide.

[0062] This method can be carried out as a continuous method in which the heterogeneous catalyst is present as part of the fixed bed in a fixed-bed reactor. Next, the halogen compound can be supplied to the fixed-bed reactor together with the epoxide and carbon dioxide. Depending on the epoxide and subsequent method conditions, the reaction in the fixed bed can be carried out in the gas phase, the liquid phase, or a combination of the gas and liquid phases. The temperature is 20 to 150°C, more preferably 40 to 120°C, and the absolute pressure is preferably 0.1 to 0.5 MPa, more preferably 0.1 to 0.3 MPa.

[0063] Carbon dioxide is appropriately brought into contact with the epoxide compound in a suspension of the liquid cyclic carbonate and heterogeneous catalyst. The temperature and pressure conditions are selected so that the cyclic carbonate is in a liquid state. Furthermore, the temperature and pressure conditions are selected so that the carbon dioxide and epoxide readily dissolve in the liquid cyclic carbonate reaction medium. The temperature can be 0 to 200°C and the pressure 0 to 5.0 MPa (absolute), and the temperature is below the boiling point of the cyclic carbonate product at the selected pressure. At the upper end of these temperature and pressure ranges, complex reaction vessels are required. Since favorable results with respect to the selectivity and yield of the desired carbonate product are obtained at lower temperatures and pressures, it is preferable that the temperature be 20 to 150°C, more preferably 40 to 120°C, and the absolute pressure be 0.1 to 0.5 MPa, more preferably 0.1 to 0.4 MPa. This method can be carried out as described, for example, in WO2021 / 094447. [Brief explanation of the drawing]

[0064] [Figure 1] This figure shows an example of a demetallated salen ligand that yields a complex after metallization. [Modes for carrying out the invention]

[0065] [Example 1] This example illustrates step (a) of a method for preparing a complex according to the present invention. The preparation of [Zn(3,4-Py-sulfen)] will be described according to the following scheme.

[0066] [ka]

[0067] In a round-bottom flask, 100 mL of methanol contained 1.44 g of 3,4-diaminepyridine (13.2 mmol), 4.8 mL of 3-tert-butylsalicyaldehyde (28.0 mmol), 3.08 g of zinc acetate dihydrate (13.8 mmol), and 5.0 mL of triethylamine (35.9 mmol). The mixture was stirred and heated under reflux for 24 hours to obtain a bright red solid. The solid was filtered and washed with methanol (3 × 20 mL). The yield of [Zn(3,4-Py-sulfen)] was 6.24 grams (95.6%).

[0068] The product is, 1 It was identified by 1H NMR. 1 ¹H NMR (300 MHz, DMSO-d6) δ values: 9.20 (s, 1H), 9.15 (s, 2H), 8.48 (d, J = 5.5 Hz, 1H), 7.88 (d, J = 5.5 Hz, 1H), 7.29 (m, 4H), 6.48 (td, J = 7.5, 3.2 Hz, 2H), 1.48 (s, 18H). The NMR data indicates that the target product was formed.

[0069] [Example 2] This example illustrates step (b) of a method for preparing the complex according to the present invention. The [Zn(3,4-Py-sulfen)] obtained in Example 1 is demetallated according to the following scheme.

[0070] [ka]

[0071] [Zn(3,4-Py-sulfen)] (6.24 g, 12.65 mmol) from Example 1 was placed in a flask and dissolved in 60 mL of toluene. Imidazole (3.48 g, 50.6 mmol) was added to this solution and the mixture was heated at 60°C for 2 hours. The solid was filtered and washed with toluene. The solid was again dissolved in methanol (60 mL) and heated at 60°C for 2 hours. The solid was filtered and dried to obtain 4.27 g of orange powder. Yield 78.6%.

[0072] The product is, 1 Identified by 1H-NMR. 1 ¹H NMR (300 MHz, DMSO-d6) δ 13.80 (s, 1H), 13.73 (s, 1H), 9.07 (d, J = 8.7 Hz, 2H), 8.71 (s, 1H), 8.58 (d, J = 5.3 Hz, 1H), 7.62 - 7.48 (m, 3H), 7.42 (td, J = 8.0, 1.7 Hz, 2H), 6.95 (td, J = 7.7, 3.3 Hz, 2H), 1.38 (s, 18H). The NMR data indicates that the target product was formed.

[0073] [Example 3] This example illustrates step (c) of a method for preparing the complex according to the present invention. The pyridine-bridged substituted salen-aluminum complex is prepared from the demetallated ligand obtained in Example 2 according to the following scheme.

[0074] [ka]

[0075] Flame-dried Schlenk was dissolved in 24 ml of toluene with the 3,4-Py-sulfen ligand (2.6 g, 6.0 mmol) obtained in Example 2, and heated to 60°C. Al(Et)2Cl (1.8 M in toluene, 6.4 mL, 11.6 mmol) was added, and the reaction mixture was stirred for 17 hours. The reaction mixture was cooled to room temperature, the product was filtered, and washed with toluene (10 mL) and pentane (2 × 10 mL) to obtain a yellow solid (1.19 g, 40%).

[0076] The product is, 1 Identified by 1H-NMR. 1 ¹H NMR (300 MHz, DMSO-d6) δ 9.50 (s, 1H), 9.44 (d, J = 5.0 Hz, 2H), 8.65 (d, J = 5.6 Hz, 1H), 8.13 (d, J = 5.7 Hz, 1H), 7.57 (td, J = 11.8, 10.6, 4.8 Hz, 4H), 6.90 - 6.75 (m, 2H), 1.56 (d, J = 1.8 Hz, 19H). The NMR data indicates that the target product was formed.

[0077] [Example 4] The substituted aluminum salen complex obtained in Example 3 (3.68 g, 7.5 mmol) was placed in a Schlenk flask that was flame-dried under a nitrogen atmosphere. Dry dimethylformamide (8.4 mL) and 3-bromopropyltrimethoxysilane (5.64 mL, 30 mmol) were added to the Schlenk flask. The reaction mixture was heated at 80°C for 48 hours to obtain an orange precipitate. Next, the reaction mixture was cooled to room temperature, the solid was isolated by centrifugation, and then washed with 3 × 10 mL of petroleum ether and 3 × 10 mL of diethyl ether to remove excess 3-bromopropyltrimethoxysilane. The resulting orange powder was dried under vacuum to obtain 5 g of a silylated compound containing DMF6 molecules.

[0078] 1H NMR: (DMSO-d6) 9.88 (br s, 1H), 9.63 (br s, 1H), 9.53 (br s, 1H), 9.07 (d, 7.00 Hz, 1H), 8.69 (d, 7.00 Hz, 1H), 7.65 (m, 4H), 7.56 (d, 7.6 Hz, 1h), 6.89 (t, 7.59 Hz, 2H), 4.55 (t, 7.20 Hz, 2H), 3.51 (s, 9H, Si-OMe), 2.11 (m, 2H), 1.56 (s, 9H), 1.55 (s, 9H), 0.70 (m, 2H)

[0079] [Example 5] 4 g of Grace Silica (particle size 40-63 μm, pore size 35 Å) was dried in a baffled flask using a Kugellow apparatus at 200°C and 50 rpm for 15 hours. The silica was cooled to room temperature, and the flask was refilled with nitrogen. Next, 30 mL of propylene carbonate was added to the silica, and the resulting slurry was heated to 130°C. The silylated chloroaluminum sulfen solution obtained in Example 4 (1.13 mL of 0.44 M dimethylformamide solution), the 3-(tributyl)ammoniumpropyltrimethoxysilane bromide solution (1.2 mL of 0.5 M acetonitrile solution), and N,N-dimethylaminopropyltrimethoxysilane (540 μL) were dissolved in 6 mL of propylene carbonate and added to the silica over 3 hours to immobilize the complex, ammonium bromide salt, and amine individually on the silica surface. At the end of the addition, the addition container was washed with 2 × 5 mL of propylene carbonate, and the reaction was continued for 18 hours. After the reaction mixture was cooled to room temperature, it was filtered through a glass fiber filter. The solid was washed with 2 × 30 mL of propylene carbonate and 2 × 30 mL of ethyl acetate, and dried under vacuum (10 mbar) at 70°C for 2 hours to obtain 4.67 g of catalyst as a yellow powder.

[0080] The molar ratio of the total number of individually immobilized aluminum moles in the heterogeneous catalyst, expressed as the number of individually immobilized aluminum moles in the salen-aluminum complex, individually immobilized tertiary amine, and individually immobilized ammonium, as measured by ICP-MS, is approximately equal to the ratio of the starting compounds described above: 1 mole of aluminum, 4 moles of amine, and 1 mole of ammonium, which is also called the Al / N / N+ (molar) ratio or the n / k / m (molar) ratio. The ammonium in this ratio is solely related to the ammonium in 3-(tributyl)ammoniumpropyltrimethoxysilane bromide.

[0081] The ICP-MS analysis results of the immobilized salen aluminum complex prepared in this example are shown in Table 1 below.

[0082] [Table 1]

[0083] [Example 6] Example 5 was repeated by individually fixing more ammonium salts so that the molar ratios of the starting compounds, expressed as molars, were 1 mole of aluminum, 4 moles of amine, and 2 moles of ammonium, respectively. In this ratio, the ammonium is related only to the ammonium in 3-(tributyl)ammoniumpropyltrimethoxysilanebromide.

[0084] [Example 7] Example 5 was repeated by individually fixing more ammonium salts so that the molar ratios of the starting compounds, expressed as molars, were 1 mole of aluminum, 4 moles of amine, and 1.5 moles of ammonium, respectively. The ammonium in this ratio is related only to the ammonium in 3-(tributyl)ammoniumpropyltrimethoxysilanebromide.

[0085] [Example 8] In this example, the catalytic activity of the heterogeneous catalysts in Examples 5, 6, and 7 was tested in the preparation of 4-phenyl-1,3-dioxolan-2-one from styrene oxide and carbon dioxide in the reaction described later, in the presence of added octyl bromide.

[0086] In a Schlenk reaction flask, 98.06 mg of heterogeneous catalyst was heated to 100°C and then evacuated. The flask was refilled with CO2 gas, and then propylene carbonate (3.33 mL), styrene oxide (1 mL), and octyl bromide (30.26 μL) were added. The flask was purged with CO2 and stirring was started. After 24 hours, the conversions of various catalysts were measured and are shown in Table 2. The main product was 4-phenyl-1,3-dioxolan-2-one.

[0087] [Table 2]

[0088] [Example 9] Example 8 was repeated using the catalyst from Example 5, except that the halogen compound was 1,4-dibromobutane (DBB) instead of octyl bromide. The experiment was carried out by varying the amount of DBB, as described in Examples 9a to 9d in Table 3. After the first run (run 1), stirring was stopped and the solid catalyst was precipitated at the bottom of the Schlenk reaction flask. Then the solvent phase of the reaction mixture was removed. Next, ethyl acetate (4 mL) was added, and the reaction mixture was stirred for 15 minutes, after which the solid catalyst was precipitated at the bottom of the Schlenk reaction flask. The solvent phase of the reaction mixture was removed. This washing operation with ethyl acetate was performed a total of two times. Next, the Schlenk reaction flask was heated to 100°C and evacuated. CO2 gas was refilled into the flask, and then propylene carbonate, styrene oxide, and 1,4-dibromobutane (if present) were added. The flask was purged with CO2, stirring was started, and the experiment of Example 8 was repeated. After 20 hours, the transformations of various catalysts were measured and described as run 2 in Table 3. This was repeated in runs 3 and 4. The results are shown in Table 3. The results indicate that for the catalyst of Example 5, a DBB content of approximately 2 mol% relative to styrene oxide is optimal. The presence of DBB improves the activity of the catalyst, and its activity is further improved when the catalyst is reused or recycled in subsequent runs during the preparation of cyclic carbonates.

[0089] [Table 3]

[0090] [Example 10] In this example, the catalytic activity of the immobilized complex obtained in Example 5 is tested in a fixed-bed reactor.

[0091] In a tubular reactor, 200 mg of pelletized catalyst was supported on quartz wool and heated to 100°C. The reaction tube was flushed with a CO2 stream (5 ml / min). A 1,2-propylene oxide stream (50 μl / min) containing a low concentration of 1-bromooctane was added to the CO2 stream (5 ml / min). The flow exiting the reaction tube was cooled using a chiller (3°C). After chilling, the liquid and gas were separated in a separator. The residual gas was sent to a scrubber. Liquid samples were periodically taken and analyzed.

[0092] The reaction tube had a diameter of 10 mm (inner diameter 8 mm), the pelletized catalyst size was 100-300 μm, and the 1-bromooctane content was 1 mol%.

[0093] The experiment was conducted continuously for 20 days. Propylene carbonate (PC) in the wastewater was analyzed on days 18 and 19. The results are shown in Table 4.

[0094] [Table 4]

[0095] [Example 11] This example describes how to prepare ligands according to the following scheme.

[0096] [ka]

[0097] In a 100 mL round-bottom flask, 2,4-dimethylphenol (7.58 g, 62.0 mmol, 3.1 eq), paraformaldehyde (1.80 g, 60.0 mmol, 3.0 eq), and 2-((2-aminoethyl)amino)ethane-1-ol (2.08 g, 20.0 mmol, 1.0 eq) were added. The reaction mixture was heated to 90°C, yielding a pale yellow solution. The reaction mixture was allowed to proceed at this temperature for 64 hours without alteration. The reaction mixture was then cooled to room temperature and dissolved in diethyl ether (25 mL) as a slightly yellow solution. A large amount of sodium sulfate was added to this solution, which was then filtered and washed with diethyl ether (2 × 5 mL). Pentane (75 mL) was added to the slightly yellow filtrate without altering the reaction mixture. When this solution was cooled to -20°C for 40 hours, a white precipitate formed in the slightly yellow solution. This suspension was filtered and washed with ice-cold diethyl ether / pentane (1:1, 20 mL twice) to obtain a white residue and a slightly yellow filtrate. The residue was dried under reduced pressure at room temperature for 2 hours. The desired product was isolated as a white powder (5.47 g, 54.0%).

[0098] Alternatively, the product can be purified by eluting with heptane / ethyl acetate / triethylamine (80:20:2) immediately after the reaction using silica column chromatography, and then eluting with heptane:isopropanol / triethylamine (90:10:2) after the yellow band disappears.

[0099] 1 H NMR (300 MHz, DMSO-d6); δ 6.78 (s, 3H, Ar-H), 6.69 (s, 2H, Ar-H), 6.56 (s, 1H, Ar-H), 3.59 (s, 6H, Ar-CH2), 3.48 (s, 2H, CH2OH), 2.68 (s, 2H, CH2), 2.60 (s, 2H, CH2), 2.48 (s, 2H, CH2CH2OH), 2.14 (s, 9H, ArCH3), 2.09 (s, 6H, ArCH3), 2.02 (s, 3H, ArCH3). 13C NMR (75 MHz, DMSO-d6): δ 153.01, 152.24, 130.36, 129.94, 127.93, 126.97, 126.71, 126.40, 123.89, 123.42, 122.49, 121.40, 58.12, 57.11, 55.25, 54.92, 49.56, 48.79, 20.13, 16.17, 15.58.

[0100] [Example 12] The method for preparing the [Ga(trisphenolate)] complex will be explained according to the following scheme.

[0101] [ka]

[0102] In a 250 mL round-bottom Schlenk flask, the trisphenolate ligand from Example 11 (4.96 g, 9.79 mmol, 1.0 eq), gallium(III) ethoxide (2.01 g, 9.79 mmol, 1.0 eq), and pre-dried THF (100 mL) were added to obtain a slightly turbid, pale yellow solution. The reaction proceeded at room temperature for 16 hours. Next, the reaction mixture was filtered through a Celite filter aid and washed with pre-dried THF (2 × 15 mL) to obtain a clear, slightly yellow solution as filtrate. The THF was then evaporated under reduced pressure and dried further at room temperature under reduced pressure for 2 hours. The Ga(trisphenolate) complex was isolated as an off-white powder, a THF adduct (6.30 g, 99.7%).

[0103] 1H NMR (300 MHz, DMSO-d6) δ 7.19 (s, 1H, OH), 6.88 - 6.73 (m, 3H, Ar-H), 6.61 (d, J = 2.2 Hz, 1H, Ar-H), 6.56 (d, J = 2.2 Hz, 1H, Ar-H), 6.48 (d, J = 2.2 Hz, 1H, Ar-H), 4.34 (d, J = 12.8 Hz, 1H, CH2), 4.16 (d, J = 13.4 Hz, 1H, CH2), 3.89 (d, J = 12.8 Hz, 1H, CH2), 3.62 (m, 2H, THF, CH2O), 3.58 - 3.31 (m, 6H, Ar-CH2)), 3.02 - 2.84 (m, 2H, CH2), 2.84 - 2.60 (m, 3H CH2), 2.20 (s, 3H, ArCH3), 2.14 (t, J = 5.7 Hz, 12H, ArCH3), 1.83 (s, 3H, ArCH3), 1.76 (m, 2H, THF, CH2). 13 C NMR (75 MHz, DMSO) δ 159.50, 157.87, 130.97, 130.75, 130.46, 127.80, 127.37, 127.10, 126.66, 126.44, 126.17, 123.49, 123.09, 121.96, 121.55, 120.69, 118.08, 67.06 (THF, CH2O), 61.33, 59.50, 55.70, 53.82, 53.26, 52.19, 25.18 (THF, CH2), 20.15, 16.93, 16.40, 15.92.

[0104] [Example 13] The method for preparing [Ga(trisphenolate)propyl(trimethoxy)silane] will be described according to the following scheme.

[0105] [ka]

[0106] Under a nitrogen atmosphere, [Ga(trisphenolate)] (5.45 g, 9.50 mmol, 1.00 eq) of Example 12, (3-isocyanatopropyl)trimethoxysilane (1.95 g, 9.50 mmol, 1.00 eq) and propylene carbonate (19 mL) were added to a 50 mL Schlenk flask to obtain a white suspension. The reaction was allowed to proceed at 60 °C for 16 hours to obtain a light brown solution. The reaction mixture was used directly for immobilization.

[0107] The same reaction can also be carried out in THF dried in advance under a nitrogen atmosphere. After the reaction, THF was evaporated under reduced pressure, and the target product [Ga(trisphenolate)propyl(trimethoxy)silane] was isolated in quantitative yield as a slightly yellow powder. The NMR data of this compound were obtained in CDCl3.

[0108] 1 H NMR (300 MHz, CDCl3) δ 7.07 - 6.25 (m, 6H, Ar-H), 5.98 (s, 1H, NH), 4.26 (d, J = 13.5 Hz, 1H, CH2), 3.96 (d, J = 13.5 Hz, 1H, CH2), 3.74 (m, 2H, CH2), 3.64 (m, 1H, CH2), 3.61 - 3.47 (m, 6H, Ar-CH2)), 3.40 (m, 1H, CH2), 3.19 - 3.01 (m, 2H, CH2), 2.93 - 2.74 (m, 2H, CH2), 2.35 - 2.02 (m, 15H, ArCH3), 1.92 - 1.80 (m, 3H, Ar-CH3), 1.71 - 1.57 (m, 1H, CH2), 1.43 (s, 9H, Si(OCH3)3, 1.31 - 1.16 (m, 1H, CH2), 0.73 - 0.44 (m, 2H, SiCH2). 13C-NMR (75 MHz, CDCl3) δ 158.58, 157.41 (br), 155.55, 132.08, 131.53, 128.61, 127.69, 126.31, 124.16, 120.88, 116.60, 77.59, 77.16, 76.74, 67.99 (THF, CH2O), 51.95, 50.58, 43.43, 30.35, 26.95, 25.64 (THF, CH2), 23.22, 20.41, 16.55, 16.24, 15.76, 8.54, 6.33. FT-IR(ATR): 1728cm -1 (s,RNH-C(O)-OR')

[0109] [Example 14] Under a nitrogen atmosphere, a mixture of N,N-dimethylaminopropyltrimethoxysilane and 3-(tributyl)ammoniumpropyltrimethoxysilane bromide [Ga(trisphenolate)propyl(trimethoxy)silane] from Example 13 was added to a 50 mL Schlenk flask, and a slightly yellow solution was obtained by adding a total of 18 mL of propylene carbonate (PC). The composition of the (co)catalyst solution is shown in Table 5 below.

[0110] [Table 5]

[0111] Using a Radleys MYA 4 reaction system equipped with a top stirrer, silica (10 g, SP540-11508, Grace GmbH, 35 Å, 40-60 μm) was dispersed in propylene carbonate (75 mL) and heated to 130°C over 45 minutes. Then, a solution prepared by dissolving [Ga(trisphenolate)propyl(trimethoxy)silane] (0.5 M propylene carbonate solution) obtained in Example 13, 3-(tributyl)ammoniumpropyltrimethoxysilane bromide (0.5 M acetonitrile solution) and N,N-dimethylaminopropyltrimethoxysilane (328 μL) in 3 mL of propylene carbonate was added over 3 hours using a syringe pump. The reaction mixture was stirred and further heated at 130°C for 18 hours, after which the reaction mixture was cooled to room temperature. The resulting slightly yellow suspension was filtered using a glass fiber filter (Whatman, 1820-055), washed with propylene carbonate (2 × 20 mL), and then washed with ethyl acetate (1 × 20 mL) to obtain a slightly yellow powder residue and a slightly yellow solution as filtrate. The residue was then dried in a vacuum oven at 70°C and 5 mbar for 2 hours. This material was used in the catalytic reaction as heterogeneous catalyst 14c. For compositions 14a, 14b, and 14d, heterogeneous catalysts 14a, 14b, and 14d were prepared in a similar manner.

[0112] [Example 15] In this example, the catalytic activity of heterogeneous catalysts 14a to 14d obtained in Example 14 was tested by preparing 4-phenyl-1,3-dioxolan-2-one through the following reaction of styrene oxide with carbon dioxide.

[0113] In a Schlenk reaction flask, 98.06 mg of heterogeneous catalyst was heated to 100°C and then evacuated. The flask was refilled with CO2 gas at ambient pressure using a balloon, and then propylene carbonate (3.30 mL) and styrene oxide (1 mL) were added. The flask was purged with CO2 and stirring was started. After 20 hours, the conversions of various catalysts were measured and are shown in Table 6. The main product was 4-phenyl-1,3-dioxolan-2-one.

[0114] [Example 16] Example 15 was repeated, except that 1,4-dibromobutane (DBB) was also added to the flask. After 20 hours, the conversion of various catalysts to styrene oxide (StO) with respect to the amount of DBB was measured and is shown in Table 6. The main product was 4-phenyl-1,3-dioxolan-2-one.

[0115] [Table 6]

[0116] [Example 17] In this example, the catalytic activity of the heterogeneous catalysts used in Examples 15 and 16 was tested for their recyclability in the reaction of styrene oxide with carbon dioxide to prepare 4-phenyl-1,3-dioxolan-2-one.

[0117] After the first run (Run 1), stirring was stopped and the solid catalyst was allowed to precipitate at the bottom of the Schlenk reaction flask. The solvent phase of the reaction mixture was then removed. Next, ethyl acetate (4 mL) was added, and the reaction mixture was stirred for 15 minutes, after which the solid catalyst was allowed to precipitate at the bottom of the Schlenk reaction flask. The solvent phase of the reaction mixture was removed. This washing procedure with ethyl acetate was performed a total of two times. Next, the Schlenk reaction flask was heated to 100°C and evacuated. CO2 gas was refilled into the flask, and then propylene carbonate (3.30 mL), styrene oxide (1 mL), and 1,4-dibromobutane (DBB, 20.92 μL) were added. The flask was purged with CO2 and stirring was started. After 20 hours, various catalyst transformations were measured and shown in Table 7 as Run 2. The main product was 4-phenyl-1,3-dioxolan-2-one.

[0118] [Table 7]

Claims

1. A heterogeneous catalyst comprising carrier particles having a carrier surface, wherein a metal complex and a halogen salt are immobilized on the carrier surface, and the metal complex and halogen salt are each individually immobilized on the carrier surface.

2. The heterogeneous catalyst according to claim 1, wherein amines are individually immobilized on the surface of a support.

3. The heterogeneous catalyst according to claim 2, wherein the amine is a tertiary amine.

4. The heterogeneous catalyst according to any one of claims 1 to 3, wherein a quaternary ammonium iodide salt and / or a phosphonium iodide salt are immobilized on the surface of the carrier as a halogen salt.

5. A heterogeneous catalyst according to any one of claims 1 to 3, wherein a quaternary ammonium bromide salt and / or a phosphonium bromide salt are immobilized as a halogen salt on the surface of the support.

6. The heterogeneous catalyst according to any one of claims 1 to 5, wherein the halogen salt is a quaternary ammonium halogen salt.

7. The heterogeneous catalyst according to any one of claims 1 to 6, wherein the carrier particles are silica, alumina and / or amorphous silica-alumina particles.

8. The heterogeneous catalyst according to claim 7, wherein a silanol group is present on the surface of silica or silica-alumina particles, and / or an aluminol group is present on the surface of alumina or silica-alumina particles, and a metal complex, an amine, and a bromide salt or iodide salt are covalently bonded to the carrier surface by alkyl(trialkoxy)silane and / or alkyltrichlorosilane anchor groups.

9. Metal complexes, tertiary amines, and halogen salts are as follows: S-(R １ -(R ２ R ３ N)) ｋ S-(R ４ -(R ５ R ６ R ７ NX)) ｍ S-(R ８ - Metal complex) ｎ [In the formula, S is the carrier surface, Tertiary amines are R １ R ２ R ３ N (wherein, R １ R is an anchor group that covalently bonds a tertiary amine to the support surface S, ２ and R ３ R is an identical or different alkyl group having 1 to 20 carbon atoms, or R ２ and R ３ is part of a ring structure that forms a five-membered ring or a six-membered ring, or R ２ or R ３ It is an aminoalkyl group. Quaternary ammonium halogen salts are R ４ R ５ R ６ R ７ NX (wherein X is a bromide or iodide anion, R ４ R is an anchor group that covalently bonds a quaternary ammonium halogen salt to the support surface S, ５ , R ６ and R ７ These are identical or different alkyl groups having 1 to 20 carbon atoms. R ８ This is an anchor group that covalently bonds the metal complex to the support surface S. k may be 0, and m:n is the molar ratio of halogen salts and metal complexes individually immobilized on the carrier surface S, or, if immobilized amines are present, k:m:n is the molar ratio of amines, halogen salts, and metal complexes individually immobilized on the carrier surface S. As shown, the heterogeneous catalyst according to any one of claims 1 to 8, wherein the catalysts are individually immobilized on the carrier surfaces of each other.

10. The heterogeneous catalyst according to claim 7, wherein the metal complex is an aluminum complex, an immobilized amine is present, and the k:m molar ratio is 3:1 to 8:

1.

11. The heterogeneous catalyst according to claim 9 or 10, wherein the metal complex is an aluminum complex and the molar ratio of n:k is 1:3 to 1:

10.

12. The silanol group is present on the surface S of the silica or silica-alumina particle, and / or the aluminol group is present on the surface S of the alumina or silica-alumina particle, and R １ , R ４ and R ８ The heterogeneous catalyst according to any one of claims 7 to 9, wherein the groups are the same or different alkyl (trialkoxy) silane anchor groups and / or alkyltrichlorosilane anchor groups.

13. The heterogeneous catalyst according to any one of claims 1 to 12, wherein the metal complex is an optionally substituted salen-aluminum complex having a pyridinium bridging group.

14. The heterogeneous catalyst according to claim 13, wherein the optionally substituted salen aluminum complex has a 3-pyridinium bridging group.

15. The salen aluminum complex has the following general formula: 【Chemistry 1】 (In the formula, B is a halogen, an ethoxy group, or an alkyl group. The phenyl group of the salen aluminum complex is optionally substituted, R ８ (where is an anchor group bonded to the carrier surface, and X is a halogen anion.) The heterogeneous catalyst according to claim 14, having the characteristics described above.

16. The heterogeneous catalyst according to claim 15, wherein X is an iodide anion or a bromide anion.

17. The heterogeneous catalyst according to claim 15 or 16, wherein the molar ratio of amine to atomic aluminum, expressed as amine moles:atomic aluminum moles, of the salen aluminum complex is greater than 3:

1.

18. The heterogeneous catalyst according to any one of claims 15 to 17, wherein X is a bromide anion, a quaternary ammonium bromide salt is immobilized as a halogen salt on the surface of the support, and the molar ratio of amine to quaternary ammonium bromide salt is 3:1 to 8:1 amine moles / quaternary ammonium nitrogen moles.

19. The heterogeneous catalyst according to any one of claims 1 to 12, wherein the metal of the metal complex is aluminum, gallium, indium, iron, cobalt, nickel, zinc, titanium and / or bismuth.

20. The heterogeneous catalyst according to claim 19, wherein the metal complex is an aminotrisphenolate metal complex.

21. The heterogeneous catalyst according to claim 20, wherein the metal is gallium.

22. Use of a heterogeneous catalyst according to any one of claims 1 to 21 as a catalyst or as part of a catalyst in a method for preparing a cyclic carbonate by reacting an epoxide compound with carbon dioxide.

23. Use of the heterogeneous catalyst according to claim 22 in the presence of an organic halogen compound.

24. The use according to claim 23, wherein the organic halogen compound is an aryl halogen compound or an alkyl halogen compound.

25. A method for preparing a cyclic carbonate, comprising reacting an epoxide compound with carbon dioxide in the presence of a heterogeneous catalyst and a halogen compound as described in any one of claims 1 to 21.

26. The method according to claim 25, wherein the heterogeneous catalyst is present as a suspension in a cyclic carbonate.

27. The method according to claim 25, wherein the heterogeneous catalyst is present as part of the fixed bed in a fixed bed reactor.

28. The method according to any one of claims 25 to 27, wherein the halogen compound is an aryl halogen compound or an alkyl halogen compound.

29. The method according to claim 28, wherein the halogen compound is a C3-C10 alkyl bromide.

30. The method according to claim 29, wherein the alkyl bromide is one of propyl bromide, butyl bromide, pentyl bromide, hexyl bromide, heptyl bromide, octyl bromide, 1,2-dibromoethane, 1,3-dibromopropane, 1,4-dibromobutane, 1,5-dibromopentane, and 1,6-dibromohexane.

31. The method according to any one of claims 25 to 30, wherein the epoxide compound has 2 to 8 carbon atoms.

32. The method according to claim 31, wherein the epoxide compound is ethylene oxide, propylene oxide, butylene oxide, pentene oxide, glycidol, styrene oxide, or fluoroethylene oxide.

33. A heterogeneous precursor catalyst comprising carrier particles having a carrier surface, wherein a metal complex is immobilized on the carrier surface and a tertiary alkylamine is immobilized on the carrier surface.

34. The heterogeneous precursor catalyst according to claim 33, wherein the metal complex is a salen-aluminum complex.

35. The heterogeneous precursor catalyst according to claim 34, wherein the molar ratio of the tertiary amine to the atomic aluminum of the salen aluminum complex and / or its oxodimer is greater than 3:1, preferably greater than 4:

1.

36. A method for activating a heterogeneous precursor catalyst, comprising contacting the heterogeneous precursor catalyst described in any one of claims 33 to 35 with a halogen compound.

37. The method according to claim 36, wherein the halogen compound is an aryl halogen compound or an alkyl halogen compound.

38. The method according to claim 37, wherein the halogen compound is a C3-C10 alkyl bromide.

39. The method according to claim 38, wherein the alkyl bromide is one of propyl bromide, butyl bromide, pentyl bromide, hexyl bromide, heptyl bromide, octyl bromide, 1,2-dibromoethane, 1,3-dibromopropane, 1,4-dibromobutane, 1,5-dibromopentane, and 1,6-dibromohexane.

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