Catalysts for the preparation of methyl acetate by carbonylation of dimethyl ether and / or methanol and their uses

Abstract

This invention relates to a catalyst for the carbonylation of dimethyl ether and / or methanol to prepare methyl acetate, comprising a first catalyst layer containing a metal supported on a support material and a second catalyst layer containing an H-type molecular sieve, wherein the first and second catalyst layers are spatially isolated. The catalyst of this invention exhibits significantly improved yields of methyl acetate and considerable selectivity. Furthermore, this invention also relates to a method for preparing methyl acetate by carbonylation of dimethyl ether and / or methanol using said catalyst.

Description

Technical Field

[0001] This invention relates to a catalyst, particularly a catalyst for the carbonylation of dimethyl ether and / or methanol to prepare methyl acetate; and a method for the carbonylation of dimethyl ether and / or methanol to prepare methyl acetate using said catalyst. Background Technology

[0002] Methyl acetate is widely used in the fragrance, coating, adhesive, and pharmaceutical industries. It is not only a good environmentally friendly solvent, capable of replacing acetone, but also an important organic raw material intermediate. Its downstream products mainly include acetic acid, ethanol, acetic anhydride, methyl acrylate, vinyl acetate, and acetamide. The demand for methyl acetate is continuously increasing both domestically and internationally. In recent years, methyl acetate has also found new applications, such as the hydrogenation synthesis of ethanol.

[0003] Industrially, methyl acetate is typically prepared from dimethyl ether and / or methanol via a carbonylation reaction.

[0004] Traditional production processes for methyl acetate via the carbonylation of dimethyl ether and / or methanol often employ homogeneous catalysis. However, this method suffers from difficulties in separating the product from the catalyst; furthermore, the use of precious metals increases production costs; and the use of iodides causes significant equipment corrosion and is detrimental to the operating environment. Wegman et al. (J Chem Soc Chem Comm 1994, (8), 947-948) developed a method using the heteropolyacid RhW 12 The carbonylation of dimethyl ether was catalyzed by PO4 / SiO2 to obtain methyl acetate in a 16% yield. Volkova et al. (Catalyst Letters 2002, 80(3-4), 175-179) applied Rh / CsxH3-xPW... 12 O 40 The carbonylation reaction of dimethyl ether was studied, and a higher RhW ratio was obtained. 12 P(VSiO2) has a reaction rate one order of magnitude higher. However, all of the above catalyst systems use precious metals, thus increasing the cost of methyl acetate production. Furthermore, these catalyst systems readily generate large amounts of hydrocarbons and carbon deposits during the dimethyl ether carbonylation reaction, necessitating frequent shutdowns of methyl acetate production to replace the catalyst.

[0005] In 2006, Iglesia et al. (Angew. Chem. Int. Ed., 2006, (10), 1617-1620) reported that mordenite (MOR) and ZSM-35 molecular sieves exhibited good dimethyl ether carbonylation activity. Because molecular sieves do not require the loading of precious metals and are easily regenerated, they effectively reduce the cost of preparing methyl acetate or acetic acid, making molecular sieve catalysts a hot topic in the study of dimethyl ether carbonylation for the preparation of methyl acetate.

[0006] Extensive research has focused on the effects of zeolite topology, acid strength and density, morphology control, and metal modification on the performance of dimethyl ether carbonylation catalysts.

[0007] In studies on the carbonylation reaction of metal-modified MOR, experimental methods such as introducing metal elements or loading a certain amount of metal elements are used to increase the acidic sites of the molecular sieve and regulate their distribution, thereby improving the activity of the molecular sieve in the carbonylation of dimethyl ether. To date, the mainstream mechanism in dimethyl ether carbonylation suggests that the activation of CO or dimethyl ether / methanol requires the assistance of both the metal functional sites and the Brønsted acid sites of the molecular sieve. This is because Weisz's proximity criterion states that the shorter the distance between the metal active site and the acidic active site, the better the interaction between them; in other words, "the closer, the better." Most related works have also demonstrated that the catalytic performance of bifunctional catalysts can be improved by adjusting and shortening the distance between the two active sites at the nanoscale.

[0008] However, MOR after metal ion exchange suffers from problems such as framework instability and easy aggregation of internal metals, and there is still room for improvement in the space-time yield and selectivity of the product methyl acetate. Furthermore, molecular sieves loaded with metals via impregnation also exhibit similar issues.

[0009] Therefore, there is a need in the art for a catalyst for the preparation of methyl acetate from dimethyl ether carbonylation that can significantly improve the space-time yield of methyl acetate and has considerable selectivity. Summary of the Invention

[0010] In view of the aforementioned state of the prior art, the inventors have conducted extensive and in-depth research on molecular sieve catalysts for the carbonylation of dimethyl ether and / or methanol to prepare methyl acetate and / or acetic acid, with the aim of discovering a novel catalyst with stable carbonylation activity. The inventors have found that by spatially isolating the metal from the molecular sieve, the space-time yield of methyl acetate can be significantly improved, with considerable selectivity. Considering the general insight in the art described above—that the closer the distance between the metal active site and the acidic active site, the better—this discovery of the present invention—that spatially isolating the metal from the molecular sieve can significantly improve the space-time yield of methyl acetate and have considerable selectivity—is surprising and unexpected.

[0011] Therefore, in a first aspect of the invention, the present invention relates to a catalyst comprising a first catalyst layer containing a metal supported on a support material and a second catalyst layer containing an H-type molecular sieve, wherein the first catalyst layer and the second catalyst layer are spatially isolated.

[0012] The metal in the first catalyst layer may be one or more of those metals commonly used in metal-modified MORs for carbonylation reactions in the art, such as Ca, Ag, Ce, Pt, Pd, Ga, Zn, Mg, Au, Co, Fe, Zr, Ni or Cu, preferably one or more of Cu, Pd, Ag, Ce, Co, Ga, Zr, Zn or Fe, and most preferably one or two of Cu or Pd.

[0013] The support material in the first catalyst layer can be a conventional inert support, such as silicon dioxide, zirconium oxide, titanium dioxide, cerium dioxide, activated carbon, graphene, carbon nanotubes or combinations thereof, preferably silicon dioxide, activated carbon, graphene, carbon nanotubes or combinations thereof.

[0014] The metal loading of the support material in the first catalyst layer can be 0.001-30% by weight, preferably 0.01-25% by weight, more preferably 0.1-20% by weight, and most preferably 0.5-15% by weight, based on the total weight of the metal and support material in the first catalyst layer in each case.

[0015] The specific surface area of ​​the metal-supported material in the first catalyst layer can be 300-700 m². 2 / g, preferably 400-600m 2 / g, determined using N2 according to the mercury porosity method in each case. Surprisingly, it was found that when the specific surface area of ​​the support material was within the above range, the resulting catalyst exhibited high space-time yield and selectivity.

[0016] The pore volume of the metal-supported material in the first catalyst layer can be 0.10-1.50 mL / g, preferably 0.20-0.70 mL / g, as determined by nitrogen adsorption-desorption BET method in each case. Surprisingly, it was found that when the pore volume of the support material is within the above range, the resulting catalyst exhibits high space-time yield and selectivity.

[0017] The pore size of the metal support material in the first catalyst layer can be 3.0-50.0 nm, preferably 7.0-10 nm.

[0018] The particle size of the carrier material can be 10-10000μm, preferably 20-5000μm, more preferably 40-1000μm, even more preferably 50-500μm, and most preferably 60-250μm.

[0019] The loading of metals onto a support material can be achieved by methods known in the art, such as impregnation, particularly wet impregnation. Wet impregnation, also known as capillary impregnation or dry impregnation, is commonly used to synthesize heterogeneous materials, i.e., catalysts. Typically, the precursor is dissolved in water or an organic solvent, and the resulting solution is then added to a catalyst support having a pore volume approximately the same as the volume of the added solution. Capillary action draws the solution into the pores of the support. The catalyst can then be dried and calcined to remove volatile components, thereby depositing the metal onto the support material.

[0020] Prior to impregnation, the carrier material can be vacuum degassed. Vacuum degassed treatment can be carried out at a temperature of 80-150°C for 0.5-10 hours. Then, the vacuum-degassed carrier is immersed in a solution of a soluble salt of the metal. The soluble salt can be a nitrate, sulfate, carboxylate, or halide, especially a chloride. For example, for copper, the soluble salt can be copper nitrate, copper sulfate, copper acetate, copper oxalate, or copper halide, wherein the copper halide can be selected from copper chloride or copper bromide, including hydrated and non-hydrated forms. Preferably, the water-soluble copper salt is copper nitrate, copper sulfate, or copper chloride. Furthermore, copper complexes, such as copper ammonia complexes, can also be used.

[0021] During the impregnation process, the carrier material can be stirred to ensure a uniform metal load. Stirring can be performed using a stirrer or with ultrasonic assistance, with ultrasonic assistance being preferred.

[0022] After impregnation, the resulting moist solid can be degassed under vacuum, then dried, and finally calcined. Vacuum degassed can be carried out at a temperature of 80-150°C for 0.5-72 hours, preferably 10-50 hours. Drying can be carried out at a temperature of 80-150°C for 0.5-24 hours. Calcination can be carried out at a temperature of 200-700°C, preferably 300-600°C, for 0.5-24 hours.

[0023] The H-type molecular sieve in the second catalyst layer can be H-type ZSM-34, ZSM-35, MOR, CHA, OFF, EU-12, Al-RUB-41 or HSUZ-4, preferably H-type OFF, EU-12, Al-RUB-41, ZSM-34 or MOR, more preferably H-type MOR (H-MOR).

[0024] The H-type molecular sieve is commercially available or can be prepared by methods known in the art, such as the solvothermal method, preferably the hydrothermal method. The hydrothermal method includes the following steps: mixing an aluminum source, a silicon source, an alkali source, an optional template agent, and water, and carrying out a hydrothermal crystallization reaction to obtain a crystallized reaction material; drying the crystallized reaction material, then calcining it, and finally reducing it to obtain the H-type molecular sieve.

[0025] The aluminum source can be selected from one or more of sodium aluminate, aluminum nitrate, aluminum isopropoxide, and aluminum chloride; the alkali source can be selected from one or more of sodium hydroxide, sodium carbonate, and potassium hydroxide; the silicon source can be selected from one or more of silica, silica sol, water glass, and organosilane; when used, the template agent can be selected from one or more of choline chloride, tetraethylammonium hydroxide, and tetramethylammonium chloride.

[0026] The amounts of aluminum source, alkali source, silicon source, optional template agent (SDA), and water are known in the art. For example, when preparing H-MOR, the molar ratio can be n(Al2O3):n(Na2O):n(K2O):n(SiO2):n(H2O):n(SDA)=1:(2.5-5.1):(0.76-9.13):(10.54-30):(130-216):(0-1.3).

[0027] Hydrothermal crystallization can be carried out in a closed container (e.g., an autoclave) under the autogenous pressure of the reaction system. The crystallization temperature range is 100-300℃, preferably 150-300℃; the crystallization time is 1 hour to 10 days, preferably 4 hours to 5 days.

[0028] During hydrothermal crystallization, a slow-release agent may be added. Suitable slow-release agents include, but are not limited to, urea, ammonium acetate, ammonium oxalate, or ammonium carbonate. The amount of slow-release agent may be 0-2.0% by weight, preferably 0.01-1.5% by weight, more preferably 0.1-1.0% by weight, based on the total weight of the reaction mixture.

[0029] After the reaction, the reaction mixture can be filtered and washed several times with distilled water (e.g., 1-10 times, preferably 1-3 times) until the washings are neutral. The filtrate is then dried. Drying can be carried out using various drying methods known in the art, such as conventional heat drying, microwave drying, and / or spray drying. In the case of heat drying, the drying temperature can be 50-200°C, preferably 80-150°C, and the drying time can be 1-24 hours, more preferably 4-20 hours, and even more preferably 8-15 hours.

[0030] After drying, the resulting product can be shaped using methods known in the art, such as tableting, ball forming, or extrusion molding. Molding can be performed with the addition of a lubricant, such as graphite. The amount of lubricant used can be 1-10%, preferably 1-5%, based on the total weight of the lubricant and the dried product. After molding, the resulting molded body can be crushed and sieved through a 40-60 mesh sieve.

[0031] After sieving, the resulting product is calcined. Calcination can be carried out using various methods known in the art, such as in a muffle furnace. The calcination temperature can be 300-800℃, preferably 350-600℃, more preferably 350-500℃; the calcination time can be 1-24 hours, preferably 1-12 hours, more preferably 1-5 hours.

[0032] In the catalyst of the present invention, the terms "first catalyst layer" and "second catalyst layer" are relative to the flow direction of the reactants (e.g., dimethyl ether and CO, etc.), that is, the first catalyst layer is located upstream of the second catalyst layer relative to the flow direction of the reactants.

[0033] In the catalyst of this invention, "spatial isolation" means that the first catalyst layer and the second catalyst are spatially separated by a macroscopically discernible distance, such as on the order of centimeters, for example 0.5-100 cm, preferably 1-100 cm, more preferably 1-50 cm, even more preferably 1-20 cm, and most preferably 1-10 cm. The first catalyst layer and the second catalyst layer can be isolated by an inert material mesh, such as quartz wool, quartz sand, activated carbon, silica, graphite, glass beads, or ceramic rings.

[0034] The weight ratio of the first catalyst layer to the second catalyst layer can be 1:10 to 10:1, preferably 1:5 to 5:1, and more preferably 1:2 to 2:1.

[0035] The catalyst of the present invention can be used as a catalyst for the preparation of methyl acetate by carbonylation of dimethyl ether and / or methanol, which can significantly improve the space-time yield of methyl acetate and has considerable selectivity.

[0036] Therefore, in another aspect of the invention, the invention relates to a method for preparing methyl acetate by carbonylation of dimethyl ether and / or methanol, wherein the catalyst of the invention is used.

[0037] According to the present invention, the carbonylation reaction can be carried out intermittently or continuously.

[0038] The catalyst of this invention can be used in any conventional form, but is preferably used in a fixed-bed configuration. In the carbonylation reaction, the reactant gas can be passed through the catalyst.

[0039] According to a preferred embodiment of the present invention, the carbonylation reaction temperature can be 180-330°C, preferably 200-280°C, for example 210-240°C, such as 220°C or 230°C. The carbonylation reaction pressure can be 0.1-40 MPa, preferably 0.5-30 MPa. The gas flow rate of the carbonylation reaction can be 0.1-2000 mL / min, preferably 0.5-200 mL / min, more preferably 5-100 mL / min, and most preferably 10-50 mL / min.

[0040] According to the present invention, in the carbonylation reaction, CO is used in molar excess relative to dimethyl ether and / or methanol. Preferably, the molar ratio of CO to dimethyl ether and / or methanol is 100:1-5:1, for example 80:1-8:1, 50:1-10:1, 40:1-12:1, 30:1-12:1, 20:1-14:1, more preferably 50:1-10:1, and even more preferably 25:1-12:1.

[0041] In one embodiment of the invention, at least one inert gas, preferably argon, is used in the carbonylation reaction. When dimethyl ether and methanol are used as raw materials, the molar ratio of the reaction gases is Ar:DME:MeOH:CO = 1:(0.1-20):(0.1-50):(1-50), preferably 1:(0.1-50):(0.1-50):(10-50). When dimethyl ether or methanol is used as raw materials, the molar ratio of the reaction gases is Ar:DME / MeOH:CO = 1:(0.1-50):(1-50), preferably 1:(0.1-50):(10-50). Wherein DME is dimethyl ether and MeOH is methanol.

[0042] When using methanol, it can be preheated and vaporized in a gasification unit. The gasification unit can be a stainless steel tubular fixed-bed reactor, filled with a non-adsorption, thermally conductive material, preferably quartz sand or glass beads. The preheating and vaporization temperature is 70-400℃, preferably 80-300℃. The preheated methanol is then passed through a catalyst along with CO and an inert gas. Upon passing through the catalytic bed, methanol is carbonylated to produce acetic acid, which then undergoes an esterification reaction with methanol to finally produce methyl acetate. Alternatively, methanol is first dehydrated to produce dimethyl ether, which is then carbonylated to produce methyl acetate.

[0043] Before the reaction, the catalyst of the present invention can be loaded into the reactor and then reduced. Reduction can be carried out using a hydrogen-containing gas, such as pure H2 or a mixture of H2 and N2 (H2 / N2). When using H2 / N2, the volume content of H2 can be 1-20%, more preferably 2-10%. The hydrogen-containing gas flow rate can be 5-500 ml / min, preferably 10-400 ml / min, more preferably 10-300 ml / min, and most preferably 80-200 ml / min. The reduction temperature can be 100-500°C, preferably 150-450°C, more preferably 200-400°C. The reduction time can be 0.5-50 hours, preferably 1-20 hours, more preferably 2-10 hours.

[0044] The technical solution for achieving the objective of this invention can be summarized as follows:

[0045] 1. A catalyst comprising a first catalyst layer containing a metal supported on a support material and a second catalyst layer containing an H-type molecular sieve, wherein the first catalyst layer and the second catalyst layer are spatially isolated.

[0046] 2. The catalyst as described in embodiment 1, wherein the metal in the first catalyst layer is one or more of Ca, Ag, Ce, Pt, Pd, Ga, Zn, Mg, Au, Co, Fe, Zr, Ni or Cu, preferably one or more of Cu, Pd, Ag, Ce, Co, Ga, Zr, Zn or Fe, and most preferably one or more of Cu or Pd.

[0047] 3. The catalyst as described in embodiment 1 or 2, wherein the support material in the first catalyst layer is silicon dioxide, zirconium oxide, titanium dioxide, cerium dioxide, activated carbon, graphene, carbon nanotubes or a combination thereof, preferably silicon dioxide, activated carbon, graphene, carbon nanotubes or a combination thereof.

[0048] 4. The catalyst according to any one of embodiments 1-3, wherein the H-type molecular sieve is H-type ZSM-34, ZSM-35, MOR, CHA, OFF, EU-12, Al-RUB-41 or HSUZ-4, preferably H-type OFF, EU-12, Al-RUB-41, ZSM-34 or MOR, more preferably H-MOR.

[0049] 5. The catalyst according to any one of embodiments 1-4, wherein the metal loading of the support material in the first catalyst layer is 0.001-30% by weight, preferably 0.01-25% by weight, more preferably 0.1-20% by weight, and most preferably 0.5-15% by weight, based on the total weight of the metal and the support material in each case.

[0050] 6. The catalyst as described in any one of embodiments 1-5, wherein the first catalyst layer and the second catalyst are spatially separated by a distance of 0.5-100 cm, preferably 1-100 cm, more preferably 1-50 cm, more preferably 1-20 cm, and most preferably 1-10 cm.

[0051] 7. A method for preparing methyl acetate by carbonylation of dimethyl ether and / or methanol, wherein a catalyst as described in any one of embodiments 1-6 is used. Detailed Implementation

[0052] The present invention will be further described below with reference to specific embodiments, but should not be construed as limiting the scope of protection of the present invention.

[0053] Example 1

[0054] Preparation of Cu / SiO2

[0055] Cu / SiO2 was prepared by initial wet impregnation. The SiO2 (CARiACT Q series, Q3, particle size 75-150 μm, pore volume 0.30 mL / g, specific surface area 550 m²) obtained from Fujisilysia, Japan, was used. 3 The carrier was 5 g SiO2, and the Cu source was Cu(NO3)2·3H2O. 5 g SiO2 was degassed under vacuum at 120 °C for 6 hours, then placed in a glass beaker. A 10 mL aqueous solution containing 2.27 g Cu(NO3)2·3H2O was slowly impregnated into the SiO2 for 30 minutes with ultrasonic assistance. During impregnation, 2 g of water was added to ensure uniform dispersion of the copper precursor solution in the SiO2. The resulting wet solid was degassed under vacuum at 120 °C for 48 hours, dried at 120 °C for 12 hours, and then calcined at 500 °C for 3 hours. The Cu loading was 12 wt%.

[0056] 0.5g Cu / SiO2 (first catalyst layer) and 0.5g H-MOR (second catalyst layer) obtained from TOSOH Corporation of Japan were placed in a stainless steel reactor with an inner diameter of 9.5mm. The distance between the Cu / SiO2 catalyst layer and the H-MOR was 1cm, and quartz wool was used for isolation.

[0057] Catalyst activity test

[0058] Before exposure to the reactants, the catalyst was pretreated in a stream of high-purity H2 at 400 °C for 3 hours at a flow rate of 20 mL / min. The reaction was carried out at a constant temperature of 220 °C and 2.0 MPa, with the reaction gas Ar / DME / CO (3.1 mol% Ar, 5.2 mol% DME, balance CO, obtained from Sumitomo Chemical) flowing through the catalyst bed at a flow rate of 20 mL / min.

[0059] Example 2

[0060] The procedure of Example 1 was repeated, except that the copper content of the Cu(NO3)2·3H2O aqueous solution was 1.14 g Cu(NO3)2·3H2O, thereby preparing Cu / SiO2 with a Cu loading of 6 wt%.

[0061] Example 3

[0062] The procedure of Example 1 was repeated, except that the copper content of the Cu(NO3)2·3H2O aqueous solution was 0.57g Cu(NO3)2·3H2O, thereby preparing Cu / SiO2 with a Cu loading of 3wt%.

[0063] Example 4

[0064] The procedure of Example 1 was repeated, except that the copper content of the Cu(NO3)2·3H2O aqueous solution was 0.29 g Cu(NO3)2·3H2O, thereby preparing Cu / SiO2 with a Cu loading of 1.5 wt%.

[0065] Example 5

[0066] The procedure of Example 1 was repeated, except that the copper content of the Cu(NO3)2·3H2O aqueous solution was 0.15g Cu(NO3)2·3H2O, thereby preparing Cu / SiO2 with a Cu loading of 0.75wt%.

[0067] Example 6

[0068] The procedure of Example 1 was repeated, except that the copper content of the Cu(NO3)2·3H2O aqueous solution was 0.11 g Cu(NO3)2·3H2O, thereby preparing Cu / SiO2 with a Cu loading of 0.6 wt%.

[0069] Example 7

[0070] The procedure of Example 1 was repeated, except that 10 mL of an aqueous solution containing 1.48 g of Pd(NO3)2 was used to prepare Pd / SiO2 with a Pd loading of 12 wt%.

[0071] Example 8

[0072] Repeat the procedure of Example 1, except that 0.5g is used via DOI. https: / / doi.org / 10.1039 / C2JM31479G H-type ZSM-34 (second catalyst layer) synthesized by the literature method was used to replace H-MOR.

[0073] Example 9

[0074] Repeat the procedure of Example 1, except that 0.5g of H-CHA (second catalyst layer) obtained from Clariant was used instead of H-MOR.

[0075] Comparative Example 1

[0076] Only H-MOR is used as a catalyst.

[0077] Comparative Example 2

[0078] Similar to Example 1, except that H-MOR is used as the first catalyst layer and Cu / SiO2 prepared in Example 1 is used as the second catalyst layer.

[0079] Comparative Example 3

[0080] Similar to Example 1, except that only Cu-MOR is used as the catalyst. The preparation of Cu-MOR is the same as in Example 1, except that H-MOR is used instead of SiO2.

[0081] Comparative Example 4

[0082] Similar to Example 1, except that Cu / SiO2 and H-MOR are physically mixed and then used as a catalyst.

[0083] The space-time yield and selectivity of methyl acetate for each catalyst were determined. The results are summarized in Table 1.

[0084] Table 1

[0085]

[0086]

[0087] As shown in Table 1, the catalyst of the present invention exhibits a significantly improved space-time yield of methyl acetate and considerable selectivity. Compared with Comparative Example 1 using pure H-MOR, the catalyst of the present invention shows a maximum improvement of 170% in the space-time yield of methyl acetate.

Claims

1. A catalyst for the carbonylation of dimethyl ether and / or methanol to prepare methyl acetate, comprising a first catalyst layer containing a metal supported on a support material and a second catalyst layer containing an H-type molecular sieve, wherein the first catalyst layer is located upstream of the second catalyst layer relative to the flow direction of the reactants, wherein the first catalyst layer and the second catalyst layer are spatially isolated, and the first catalyst layer and the second catalyst layer are spatially separated by 0.5-100 cm, wherein the metal in the first catalyst layer is one or more of Ag, Pt, Pd, Zn, Au or Cu, and wherein the H-type molecular sieve is H-type ZSM-34, ZSM-35, MOR, CHA, OFF, EU-12, Al-RUB-41 or HSUZ-4.

2. The catalyst of claim 1, wherein the metal in the first catalyst layer is one or both of Cu and Pd.

3. The catalyst of claim 1, wherein the support material in the first catalyst layer is silicon dioxide, zirconium oxide, titanium dioxide, cerium dioxide, activated carbon, graphene, carbon nanotubes or a combination thereof.

4. The catalyst of claim 2, wherein the support material in the first catalyst layer is silicon dioxide, activated carbon, graphene, carbon nanotubes or a combination thereof.

5. The catalyst according to any one of claims 1-4, wherein the H-type molecular sieve is H-type OFF, EU-12, Al-RUB-41, ZSM-34 or MOR.

6. The catalyst according to claim 5, wherein the H-type molecular sieve is H-MOR.

7. The catalyst according to any one of claims 1-4, wherein the metal loading of the support material in the first catalyst layer is 0.001-30% by weight, based on the total weight of the metal and the support material in each case.

8. The catalyst of claim 7, wherein the metal loading of the support material in the first catalyst layer is 0.01-25% by weight, based on the total weight of the metal and the support material in each case.

9. The catalyst of claim 7, wherein the metal loading of the support material in the first catalyst layer is 0.1-20% by weight, based on the total weight of the metal and the support material in each case.

10. The catalyst of claim 7, wherein the metal loading of the support material in the first catalyst layer is 0.5-15% by weight, based on the total weight of the metal and the support material in each case.

11. The catalyst according to any one of claims 1-4, wherein the first catalyst layer and the second catalyst are spatially separated by a distance of 1-100 cm.

12. The catalyst of claim 11, wherein the first catalyst layer and the second catalyst are spatially separated by a distance of 1-50 cm.

13. The catalyst of claim 11, wherein the first catalyst layer and the second catalyst are spatially separated by a distance of 1-20 cm.

14. The catalyst of claim 11, wherein the first catalyst layer and the second catalyst are spatially separated by a distance of 1-10 cm.

15. A method for preparing methyl acetate by carbonylation of dimethyl ether and / or methanol, wherein the catalyst according to any one of claims 1-14 is used.

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