MIXTURE INTENDED FOR USE AS A LIQUID SORPTION AGENT IN THE SYNTHESIS OF METHANOL, AND PROCESS FOR THE SYNTHESIS OF METHANOL BY MEANS OF THIS MIXTURE

Abstract

The invention relates to a mixture intended to be used as a liquid sorption agent in the synthesis of methanol, and a process for the synthesis of methanol using this mixture. The mixture consists of a component a) in the form of at least one di(trifluoromethylsulfonyl)imide salt containing an organic cation, and a component b) which is formed of a salt made from one of the anions [po4]3-~, [hpo4]2-, [h2po4]-, [so4]2-, [hso4]-, [no3]-, [no2]- or c1- and one or two or three cations suitable for a), the number of cations corresponding to the absolute value of the atomic number of the respective anion (component b1), a di(trifluoromethylsulfonyl)imide salt containing a metallic cation (component b2) and / or a zwitterionic compound (component b3).In its liquid state, the mixture exhibits good dissolving properties in methanol and water and can be used as a liquid sorption agent, particularly in the synthesis of methanol. This invention further relates to a process for synthesizing methanol using said mixture.

Description

[0001] The present invention relates to a mixture for use as a liquid sorbent in methanol synthesis and to a method for carrying out methanol synthesis using the mixture.

[0002] Many chemical syntheses involve so-called equilibrium-limiting reactions, meaning that the synthesis of products stops (from an external perspective) when an equilibrium is reached between reactants and product(s). In such syntheses, it is therefore advantageous for a high degree of conversion to remove product(s) from the synthesis system, either to prevent the establishment of an equilibrium between reactants and product(s) or to return from an equilibrium state to a non-equilibrium state. This can be achieved, for example, by continuously or discontinuously removing product(s) from the reaction system.

[0003] Two well-known examples of a chemical synthesis under an equilibrium-limiting reaction are the production of methanol from hydrogen and carbon monoxide according to the following reaction equation 1, or from hydrogen and carbon dioxide according to the following reaction equation 2: 1. 2H 2 + CO ⇄ CH 3 OH 2. 3H 2 + CO 2 ⇄ CH 3 OH + H 2 O

[0004] Currently, methanol synthesis primarily takes place in heterogeneous, catalyzed fixed-bed reactors, where the reactants are only partially converted in a single pass through the reactor. The condensable reaction products are therefore separated after one pass, and the unreacted reactants are recirculated to the reaction site. The recirculation of the sometimes large volumes of gas results in significant equipment costs.

[0005] To overcome or at least reduce this disadvantage, a process for carrying out a chemical synthesis using two only partially soluble support phases and a catalyst dispersed in one of the support phases is known from DE 10 2015 202 681 A1, in which the support phases are mixed in a reactor, at least one synthesis reactant is introduced into the reactor and the two support phases are subsequently separated from each other.

[0006] In methanol synthesis, the synthesis product methanol, or methanol and water, exhibits an affinity for polar liquids, causing them to accumulate in such liquids. Therefore, according to the aforementioned publication, one of the carrier phases in methanol synthesis is preferably a polar liquid, which can be composed of ionic liquid(s), polar solvent(s), or one or more higher molecular weight alcohols.

[0007] The synthesis product(s) accumulate in the polar support phase, thereby preventing the establishment of a steady-state equilibrium situation in the other, less polar or nonpolar support phase, which (at least predominantly) contains the reactants and the catalyst required for methanol synthesis, until the saturation limit in the polar support phase is reached.

[0008] In a further process step, the two carrier phases are separated, for example by removing the polar carrier phase from the reactor, and the synthesis product(s) (methanol or methanol and water) are at least partially separated from the polar carrier phase. The polar carrier phase, now "freed" of the synthesis products, can then be returned to the reactor.

[0009] The ionic liquids mentioned as possible carrier phases are salts that melt at low temperatures (<100°C) and represent a class of solvents with extremely low vapor pressure.

[0010] Although the first examples have been known since 1914, ionic liquids have only been intensively investigated as solvents for chemical reactions for about 15 years. The extremely low vapor pressure of ionic liquids is a great advantage for certain processes, as it allows for the extractive separation of a reaction mixture without contaminating the gas phase with solvent vapors. The extract can often be recovered from the ionic liquid by simple distillation, avoiding problems such as azeotrope formation between the solvent and the extract.

[0011] By appropriately selecting the cation and anion of an ionic liquid, its polarity and thus its solubility properties can be precisely controlled. The range extends from water-miscible to water-immiscible ionic liquids, and even to those that form two phases with organic solvents or other ionic liquids. Skillful exploitation of their exceptional solubility properties is key to the successful application of ionic liquids as a novel class of solvents.

[0012] Problems can arise when using ionic liquids at higher temperatures, as many are not permanently temperature-stable above 200°C. Furthermore, the presence of catalysts, reactants, and reaction products can significantly restrict the choice of cations and anions from a stability perspective.

[0013] P. Wasserscheid, W. Keim: "Ionic liquids - new "solutions" for transition metal catalysis", Angew. Chem., Volume 112, Issue 21, pp. 3926-3945, November 3, 2000, describes the use of ionic liquids as extraction media in two-phase catalysis.

[0014] Although ionic liquids are already mentioned in the prior art as a possible carrier phase in connection with methanol synthesis (see WO 2010 / 107929 A2 or DE 10 2015 215662 A1), the use of ionic liquids as a sorbent (extraction phase) of methanol or methanol and water under the reaction conditions of methanol gas-phase synthesis using carbon monoxide and hydrogen, carbon dioxide and hydrogen or a mixture of carbon monoxide, carbon dioxide and hydrogen represents a problem that has not yet been solved.

[0015] This is because particularly high demands are placed on the stability of the ionic liquid(s) used at temperatures up to 300°C and up to 300 bar synthesis gas pressure in the presence of a catalyst, such as Cu-Zn oxide on aluminum oxide, and the reaction products.

[0016] It would also be advantageous if the ionic liquid in methanol synthesis using carbon dioxide and hydrogen had equally good sorption properties with respect to the synthesis products water and methanol, in order to avoid an accumulation of one of the synthesis products in the gas phase.

[0017] Against this background, the object of the present invention is to provide novel sorbents for methanol or methanol and water in methanol synthesis based on ionic liquids and a process for methanol synthesis using such sorbents.

[0018] These problems are solved by the mixture according to claim 1 and the method according to claim 7. Advantageous further developments of the mixture and the method are the subject of the dependent claims.

[0019] According to the present invention, a mixture for use as a liquid sorbent for methanol or methanol and water in the methanol synthesis using carbon monoxide and hydrogen, carbon dioxide and hydrogen, or a mixture of carbon monoxide, carbon dioxide, and hydrogen as synthesis starting materials is proposed, wherein the mixture is characterized in that it consists of I) of a component A) in the form of at least one salt formed from the bis(trifluoromethylsulfonyl)imide anion and a cation in the form of a quaternary ammonium cation of the general formula [NR 1< R 2< R 3< R] +< ; or a phosphonium cation of the general formula [PR 1< R 2< R 3< R] +< ; wherein the residues R 1< , R 2< , R 3< are independently selected from hydrogen; linear or branched, saturated or unsaturated, aliphatic or alicyclic alkyl groups with 1 to 20 carbon atoms, wherein up to 6 hydrogen residues may be substituted by OH groups;Heteroaryl groups and / or heteroaryl C1-C6 alkyl groups with 3 to 8 carbon atoms, preferably 4 to 8 carbon atoms in the heteroaryl residue and at least one heteroatom in the heteroaryl residue selected from N, O and S, wherein the alkyl groups can be linear or branched, saturated or unsaturated, aliphatic or alicyclic and wherein one or more hydrogen residues on the heteroaryl residue can be substituted with at least one group, which can be selected independently from linear or branched, saturated or unsaturated, aliphatic or alicyclic C1-C6 alkyl groups and / or halogen atoms;Aryl and / or aryl-C1-C6 alkyl groups with 6 to 20 carbon atoms in the aryl residue, wherein the alkyl groups can be linear or branched, saturated or unsaturated, aliphatic or alicyclic, and wherein one or more hydrogen residues on the aryl residue can be substituted with at least one group that can be selected independently from linear or branched, saturated or unsaturated, aliphatic or alicyclic C1-C6 alkyl groups and / or halogen atoms; and [-(CH2)x-O-]y-CH3 groups with x=2-5 and y=1-20; and the residue R is selected from linear or branched, saturated or unsaturated, aliphatic or alicyclic alkyl groups with 1 to 20 carbon atoms, wherein up to 6 hydrogen residues can be substituted by OH groups;Heteroaryl-C1-C6 alkyl groups with 3 to 8 carbon atoms, preferably 4 to 8 carbon atoms in the heteroaryl residue and at least one heteroatom in the heteroaryl residue selected from N, O and S, wherein the alkyl groups can be linear or branched, saturated or unsaturated, aliphatic or alicyclic and wherein one or more hydrogen residues on the heteroaryl residue can be substituted with at least one group, which can be selected independently from linear or branched, saturated or unsaturated, aliphatic or alicyclic C1-C6 alkyl groups and / or halogen atoms;Aryl-C1-C6 alkyl groups with 6 to 20 carbon atoms in the aryl residue, wherein the alkyl groups can be linear or branched, saturated or unsaturated, aliphatic or alicyclic, and wherein one or more hydrogen residues on the aryl residue can be substituted with at least one group that can be selected independently from linear or branched, saturated or unsaturated, aliphatic or alicyclic C1-C6 alkyl groups and / or halogen atoms; and -[-(CH2)x-O-]y-CH3 groups with x=2-5 and y=1-20; and II) a component B), which consists of at least the following component: B3) a zwitterionic compound formed from one of the cations mentioned in A), in which one of the residues R, R1< , R2< or R3< is a -(CH2)x-SO3-< group with x = 1-10. ;

[0020] In component B3), the residues R, R 1< , R 2< or R 3< include all those mentioned with respect to component A), where additionally each of the residues R, R 1< , R 2< or R 3< can also be a -(CH 2 ) x -SO 3 -< -group with x = 1-10 and one of the residues R, R 1< , R 2< or R 3< is actually a -(CH 2 ) x -SO 3 -< -group with x = 1-10.

[0021] Component B) can further consist of at least one of the following components: B1) a salt formed from one of the anions [PO₄]³⁻, [HPO₄]²⁻, [H₂PO₄]⁻, [SO₄]²⁻, [HSO₄]⁻, [NO₃]⁻, [NO₂]⁻, or Cl⁻ and one, two, or three of the cations mentioned in A), wherein the number of cations corresponds to the absolute value of the charge of the respective anion; B2) a salt formed from one or more bis(trifluoromethylsulfonyl)imide anions and a lithium, potassium, cesium, magnesium, calcium, barium, nickel, cobalt, iron, scandium, lanthanum, zinc, gallium, cerium or aluminium cation, wherein the number of bis(trifluoromethylsulfonyl)imide anions corresponds to the absolute value of the charge of the respective metal cation.

[0022] The mixture according to the present invention can therefore comprise one or more of the components A) and one or more of the components B1, B2 and / or B3.

[0023] As the inventors discovered, organic salts with an organic cation and the bis(trifluoromethylsulfonyl)imide anion are liquid and sufficiently stable under the reaction conditions given in the synthesis of methanol from carbon monoxide and hydrogen, carbon dioxide and hydrogen or a mixture of carbon monoxide, carbon dioxide and hydrogen (temperatures in the range of 200°C to 300°C and pressures in the range of 50 bar to 300 bar).

[0024] However, these organic salts—due to the nature of the anion—always exhibit very hydrophobic properties, meaning they have very low water- and / or methanol-dissolving properties. Because of the low solubility of these reaction products, the desired effect of shifting the equilibrium by dissolving water and / or methanol into the ionic liquid during methanol synthesis is not sufficiently achieved.

[0025] The (additional) use of one or more known water- and / or methanol-soluble organic ionic liquid(s) is not possible, as this would lead to gaseous decomposition products due to their thermal instability, which would deactivate the catalyst used.

[0026] Surprisingly, it has now been found that by a mixture of at least one of the above-mentioned components A (i.e. a thermally stable, organic bis(trifluoromethylsulfonyl)imide salt) and at least the above-mentioned component B3 (zwitterionic compound), more water- and methanol-soluble, thermally stable, low-melting sorption phases are obtained, which can be successfully used in the methanol synthesis from carbon dioxide (CO2) and / or carbon monoxide (CO) with hydrogen (H2).

[0027] As experiments have shown, for example, in the synthesis of methanol using carbon dioxide and hydrogen, by using a mixture according to the invention as a liquid sorbent, a shift in equilibrium by a factor of 4 or more can be achieved by sorption of the reaction products water and methanol from the gaseous reaction phase, i.e., more than four times more methanol is formed in the closed reactor than would be possible under equilibrium conditions without the mixture according to the invention.

[0028] According to a first advantageous embodiment of the mixture, the mass fraction of component B), i.e. the sum of the mass fractions in the ionic liquid, is in the range of 1% to 99%, preferably in the range of 1% to 80%.

[0029] As the inventors also surprisingly discovered, a comparatively small mass fraction of component B) is often sufficient to achieve a significantly improved water- and / or methanol-dissolving property of the mixture compared to component A) alone. A person skilled in the art can determine the mass fraction of the respective component B) in the mixture with the respective component A) that produces the required or desired dissolving properties with respect to water and / or methanol through just a few experiments.

[0030] According to a further advantageous embodiment, the mixture according to the invention is one that is liquid at a temperature of 79°C and above, preferably 49°C and particularly preferably 19°C and above. Since the mixtures according to the present invention are provided as a liquid sorption phase, it is essential that they remain liquid under the temperature conditions prevailing during the sorption process.

[0031] If the sorption process takes place, for example, during gas-phase methanol synthesis ("in situ"), where reaction temperatures range from approximately 100°C to approximately 300°C, a mixture must be selected that is liquid within this temperature range. If the sorption process takes place, for example, outside the reactor ("ex situ"), where temperatures may be lower than in the reactor, or if the sorption process occurs in a region of the reactor where temperatures are lower than in the actual "reaction zone," a mixture must be selected that is liquid at the given lower temperatures. A person skilled in the art can determine one or more suitable mixtures through a few experiments.

[0032] As the inventors discovered, in many cases the claimed mixtures exhibit a melting point of at least 80°C when component A) is present in the mixture at a mass ratio of 20% or more. The respective melting point of a mixture can be determined by a simple experiment, and the components of the mixture and their mixing ratios (mass ratios) can be selected such that both a desired or required melting point and a desired degree of methanol- and / or water-soluble property are achieved.

[0033] The inventors were able to show that in many cases, over a certain mass fraction range of component B), a linear relationship exists between the increase in methanol and / or water-soluble property and the increase in the mass fraction of component B).

[0034] The mixtures according to the invention are obtained by intensive mixing of the components they contain. All of the individual components can be produced by methods known to those skilled in the art and are also commercially available (if necessary, upon special order).

[0035] Where the present application refers to an alkyl, alkoxy, or aminoalkyl group being branched, this naturally presupposes that the group has the required minimum of 3 carbon atoms; where the present application refers to a group being unsaturated, this naturally presupposes that it has at least 2 atoms that can form a double bond with each other (e.g., at least 2 carbon atoms); where the present application refers to a group being alicyclic, this naturally presupposes that the group has at least 3, preferably 4, 5, 6, or more carbon atoms;If the present application states that up to 6 hydrogen residues in a group can be substituted by OH groups, this naturally presupposes that the group has the required number of substitutable hydrogen residues (in a C1 group, a maximum of 3 hydrogen residues can be substituted; in a saturated C2 group, a maximum of 5 hydrogen residues;etc.). Where the present application refers to an aryl group with 6 to 20 carbon atoms, this may, depending on the number of carbon atoms, be a monocyclic (e.g., with up to 10 carbon atoms) or polycyclic (e.g., from 10 carbon atoms) aryl group, whereby the rings of a polycyclic aryl group may be fused or linked to each other by means of a C-C bond (as, for example, in biphenyl). And where the present application refers to "halogen atoms," these are to be understood as fluorine, chlorine, bromine, and / or iodine atoms or groups.

[0036] The following is a preferred example of the mixture: tributylmethylphosphonium bis(trifluoromethylsulfonyl)imide, lithium bis(trifluoromethylsulfonyl)imide and tributyl-4-sulfonyl-1-butanephosphonium.

[0037] In the specified mixture, the mass ratio of the first specified component to the second specified component to the third specified component is preferably in the range of four to one to one, through four to three to one, up to four to three to three. Such mass ratios are also regularly suitable for other binary and ternary mixtures according to the present invention.

[0038] Of course, the present invention is not limited to the examples mentioned above and the preferred mass ratios indicated; rather, the scope of protection of the present invention is determined by the content of the patent claims.

[0039] The present invention does not encompass the use of the mixtures according to the present invention in a methanol synthesis, in particular a gas-phase methanol synthesis, as a liquid sorbent for methanol or methanol and water.

[0040] The present invention also encompasses a process for carrying out a methanol synthesis, in particular a gas-phase methanol synthesis, using carbon monoxide and hydrogen, carbon dioxide and hydrogen or a mixture of carbon monoxide, carbon dioxide and hydrogen as synthesis reactants in a reactor at a temperature in the range of 100°C and 300°C and a synthesis gas pressure in the range of 50 bar to 300 bar in the presence of a catalyst, comprising the following steps: Providing a liquid mixture according to the invention or one of its advantageous embodiments in the reactor; converting carbon monoxide and hydrogen, carbon dioxide and hydrogen, or a mixture of carbon monoxide, carbon dioxide, and hydrogen to the synthesis product methanol or the synthesis products methanol and water in the reactor at a temperature in the range of 100°C to 300°C and a synthesis gas pressure in the range of 50 bar to 300 bar; sorption of at least a subset of at least one synthesis product from the gas phase containing at least one synthesis product into the liquid mixture; and continuous or discontinuous discharge of the liquid mixture from the reactor.

[0041] There are no special restrictions regarding the reactor, and any reactor known from the prior art for the stated purpose can be used, e.g., one as described in DE 10 2015 202 681 A1. In this regard, and also with regard to the possible reaction procedure, explicit reference is made to this publication.

[0042] A suitable quantity of the mixture according to the invention, or one of its advantageous embodiments, can be introduced into the reactor, which can then be heated to a temperature suitable for methanol synthesis in the range of 100°C to 300°C (e.g., in the range of 200°C), or can already be at a suitable temperature when the mixture is introduced. In this way, the mixture according to the invention is always present in liquid form in the reactor. Of course, the mixture can also already be at a liquid temperature outside the reactor, and the mixture can be introduced into the reactor in liquid form.

[0043] Above the mixture in the reactor, the pelletized or particulate catalyst required for methanol synthesis can be arranged, for example, in a basket-like container. By introducing the synthesis gases carbon monoxide and hydrogen, carbon dioxide and hydrogen, or a mixture of carbon monoxide, carbon dioxide, and hydrogen into the reactor and adjusting the synthesis gas pressure to a range of 50 bar to 300 bar (e.g., around 80 bar) and a reactor temperature to a range of 100°C to 300°C (e.g., 200°C), the synthesis gas reactants are converted into the synthesis gas product(s), methanol or methanol and water.

[0044] Due to the methanol-soluble or methanol-water-soluble properties of the liquid mixture according to the present invention, at least a portion of the synthesis product methanol or the synthesis products methanol and water passes into the mixture, thereby shifting the equilibrium in the above reaction equations 1) and 2) in the direction of the reactants. Thus, a much larger proportion of reactants can be converted into the product(s) in the reactor than would be possible without the presence of the mixture according to the present invention.

[0045] Once a sufficient, desired, or maximum possible amount of the reaction product(s) has entered the liquid mixture, it is discharged from the reactor.

[0046] In the process according to the present invention, the gas phase containing at least one synthesis product can advantageously be introduced into the liquid mixture by means of a gas introduction stirrer during or after the methanol synthesis process. This allows the sorption of the reaction product methanol, or of the reaction products methanol and water, to proceed more rapidly compared to processes without such a measure. Of course, sorption from the gas phase of the synthesis product(s) can also be accelerated by other suitable measures, for example, by injecting the gas phase into the liquid mixture.

[0047] The process according to the present invention can advantageously be further developed such that the liquid mixture discharged from the reactor is depressurized and that at least one of the synthesis products, methanol, which thereby at least partially emerges from the mixture, is recovered. From a sufficiently hot or warm liquid mixture, the synthesis product methanol, or the synthesis products methanol and water, emerge in gaseous form and can then be condensed, for example, by cooling.

[0048] It is also advantageous if, in the process according to the present invention, after the pressure reduction of the liquid mixture and the at least partial release of the synthesis product methanol or the synthesis products methanol and water from the mixture, the mixture is returned to the reactor. The return of the mixture preferably occurs in a liquid state. The return of the mixture to the reactor—as well as its discharge from the reactor—can be continuous or batchwise. The same applies to the supply of the synthesis reactants.

[0049] Thus, the present invention enables a continuous methanol synthesis, wherein at least partial amounts of the synthesis product methanol or the synthesis products methanol and water can be transferred into the liquid mixture and continuously or batchwise discharged from the reactor. Outside the reactor, the mixture can be depressurized, the discharged synthesis product(s) recovered, and the mixture, at least partially freed of the synthesis product(s), returned to the reactor for the resorption of synthesis product(s).

[0050] In the process according to the present invention, any suitable catalyst can be used, but preferably copper-zinc oxide on aluminum oxide is used as the catalyst, which is arranged in the gas phase of the reactor.

[0051] A preferred example of the process according to the present invention is one in which carbon dioxide and hydrogen are used as synthesis gas, at least partial amounts of the synthesis products methanol and water are sorbed into the liquid mixture in the reactor, after the mixture is discharged from the reactor and the mixture is depressurized (i.e., the pressure above the mixture is reduced), the synthesis products methanol and water are at least partially released from the mixture, at least the released synthesis product methanol is recovered (e.g., by condensation), and after the liquid mixture is depressurized and the synthesis products are at least partially released from the mixture, it is returned to the reactor (preferably in liquid form).

[0052] The method according to the present invention can advantageously be further developed in such a way that heat is extracted from the mixture before it is returned to the reactor, i.e., that the temperature of the mixture is lowered.

[0053] The mixtures according to the present invention can be used in the liquid state as sorbents for methanol and / or water in all processes where such sorption is desired, not only in the context of methanol gas-phase synthesis. A currently preferred application is their use "in situ," i.e., in methanol gas-phase synthesis, but their use is not limited to this. Sorption of methanol and / or water can take place or be carried out under all suitable pressure (e.g., also at atmospheric pressure) and temperature conditions (i.e., from a temperature at which the respective mixture is liquid).

[0054] Insofar as the term "sorption agent" is used in the present application, it is understood, according to the generally accepted definition, to mean an agent that is capable of causing an enrichment of at least one substance (here: methanol and / or water) within a phase (here: the liquid mixture according to the invention or one of its advantageous embodiments) or at an interface between two phases (here: at the interface formed between a gas phase containing methanol and / or water and the liquid phase of the liquid mixture according to the invention or one of its advantageous embodiments). A sorption agent can thus cause an enrichment of at least one substance within a phase (i.e., absorption) and / or an enrichment at an interface (i.e.,an adsorption), wherein, in the case of the mixtures according to the present invention, when used as liquid sorbents, it can be assumed that exclusively or predominantly an absorption of methanol and / or water takes place.

Claims

1. Mixture for use as liquid sorbent for methanol or methanol and water in methanol synthesis using carbon monoxide and hydrogen, carbon dioxide and hydrogen or a mixture of hydrogen, carbon monoxide and carbon dioxide as synthesis reactants, characterized in that the mixture consists of I) a component A) in the form of at least one salt, which is formed from the bis(trifluoromethylsulfonyl)imide anion and a cation in the form of a - quaternary ammonium cation of the general formula [NR1R2R3R]+; or - a phosphonium cation of the general formula [PR1R2R3R]+; wherein the radicals R1, R2, R3 are independently selected from hydrogen; linear or branched, saturated or unsaturated, aliphatic or alicyclic alkyl groups having 1 to 20 carbon atoms, where up to 6 hydrogen radicals may be substituted by OH groups; heteroaryl groups and / or heteroaryl-C1-C6-alkyl groups having 3 to 8 carbon atoms in the heteroaryl radical and at least one heteroatom in the heteroaryl radical that is selected from N, O and S, wherein the alkyl groups may be linear or branched, saturated or unsaturated, aliphatic or alicyclic and wherein one or more hydrogen radicals on the heteroaryl radical may be substituted by at least one group which is independently selectable from linear or branched, saturated or unsaturated, aliphatic or alicyclic C1-C6-alkyl groups and / or halogen atoms; aryl and / or aryl-C1-C6-alkyl groups having 6 to 20 carbon atoms in the aryl radical, wherein the alkyl groups may be linear or branched, saturated or unsaturated, aliphatic or alicyclic and wherein on the aryl radical one or more hydrogen radicals may be substituted by at least one group which is independently selectable from linear or branched, saturated or unsaturated, aliphatic or alicyclic C1-C6-alkyl groups and / or halogen atoms; and - [-(CH2)x-O-]y-CH3 groups where x = 2-5 and y = 1-20; and - the radical R is selected from linear or branched, saturated or unsaturated, aliphatic or alicyclic alkyl groups having 1 to 20 carbon atoms, where up to 6 hydrogen radicals may be substituted by OH groups; heteroaryl-C1-C6-alkyl groups having 3 to 8 carbon atoms in the heteroaryl radical and at least one heteroatom in the heteroaryl radical that is selected from N, O and S, wherein the alkyl groups may be linear or branched, saturated or unsaturated, aliphatic or alicyclic and wherein one or more hydrogen radicals on the heteroaryl radical may be substituted by at least one group which is independently selectable from linear or branched, saturated or unsaturated, aliphatic or alicyclic C1-C6-alkyl groups and / or halogen atoms; aryl-C1-C6-alkyl groups having 6 to 20 carbon atoms in the aryl radical, wherein the alkyl groups may be linear or branched, saturated or unsaturated, aliphatic or alicyclic and wherein one or more hydrogen radicals on the aryl radical may be substituted by at least one group which is independently selectable from linear or branched, saturated or unsaturated, aliphatic or alicyclic C1-C6-alkyl groups and / or halogen atoms; and -[-(CH2)x-O-]y-CH3 groups where x = 2-5 and y = 1-20; and II) a component B) which consists of at least the following components: B3) a zwitterionic compound that is formed from one of the cations stated in A), in which one of the radicals R, R1, R2 or R3 is a -(CH2)x-SO3- group where x = 1-10.

2. Component B) according to Claim 1, additionally composed of at least one of the following components: B1) a salt that is formed from one of the anions [PO4]3-, [HPO4]2-, [H2PO4]-, [SO4]2-, [HSO4]-, [NO3]-, [NO2]- or Cl- and one, two or three of the cations stated in A), wherein the number of cations corresponds to the absolute value of the charge number of the respective anion; B2) a salt that is formed from one or more bis(trifluoromethylsulfonyl)imide anions and a lithium, potassium, cesium, magnesium, calcium, barium, nickel, cobalt, iron, scandium, lanthanum, zinc, gallium, cerium or aluminum cation, wherein the number of bis(trifluoromethylsulfonyl)imide anions corresponds to the absolute value of the charge number of the respective metal cation.

3. Mixture according to Claim 1 or Claim 2, characterized in that the proportion by mass of component B) in the mixture is in the range from 1% to 99%, preferably in the range from 1% to 80%.

4. Mixture according to any of the preceding claims, characterized in that it is liquid at a temperature from 79°C, preferably from 49°C, particularly preferably from 19°C.

5. Mixture according to any of the preceding claims, characterized in that it consists of tributylmethylphosphonium bis(trifluoromethylsulfonyl)imide, lithium bis(trifluoromethylsulfonyl)imide and tributyl-4-sulfonyl-1-butanephosphonium.

6. Mixture according to Claim 5, characterized in that the mass ratio of the first component specified to the second component specified to the third component specified is in the range from 4:1:1 through 4:3:1 to 4:3:3.

7. Method for conducting a methanol synthesis using carbon monoxide and hydrogen, carbon dioxide and hydrogen or a mixture of carbon monoxide, carbon dioxide and hydrogen as synthesis reactants in a reactor at a temperature in the range from 100°C to 300°C and a synthesis gas pressure in the range from 50 bar to 300 bar in the presence of a catalyst, comprising the following steps: - providing a liquid mixture according to any of Claims 1 to 6 in the reactor; - converting carbon monoxide and hydrogen, carbon dioxide and hydrogen or a mixture of carbon monoxide, carbon dioxide and hydrogen to the synthesis product methanol or the synthesis products methanol and water in the reactor at a temperature in the range from 100°C to 300°C and a synthesis gas pressure in the range from 50 bar to 300 bar; - sorbing at least one subamount of at least one synthesis product, from the gas phase comprising at least one synthesis product, into the liquid mixture; and - continuously or discontinuously guiding the liquid mixture out of the reactor.

8. Method according to Claim 7, characterized in that the gas phase comprising at least one synthesis product is introduced into the mixture by means of a sparging stirrer.

9. Method according to Claim 7 or 8, characterized in that the liquid mixture guided out of the reactor is depressurized and in that at least the methanol - at least partially emerging from the mixture as a result - is recovered.

10. Method according to Claim 9, characterized in that, after the depressurization of the liquid mixture and the at least partial emergence from the mixture of the synthesis product methanol or the synthesis products methanol and water, the mixture is recycled back into the reactor.

11. Method according to any of Claims 7 to 10, characterized in that the catalyst used is copper / zinc oxide on aluminum oxide, said catalyst being arranged in the synthesis-gas gas phase of the reactor.

12. Method according to any of Claims 7 to 11, characterized in that the synthesis gas used is carbon dioxide and hydrogen; at least subamounts of the synthesis products methanol and water are absorbed into the liquid mixture in the reactor; the guidance of the mixture out of the reactor and the depressurization of the mixture is followed by the synthesis products methanol and water at least partially emerging from the mixture; at least the synthesis product methanol that has at least partially emerged is recovered; and the depressurization of the liquid mixture and the at least partial emergence of the synthesis products from the mixture is followed by the mixture being recycled back into the reactor.

13. Method according to any of Claims 10 to 12, characterized in that heat is extracted from the mixture prior to recycling into the reactor.