CN108238846B

CN108238846B - Preparation method of catalyst for ethanol synthesis, catalyst obtained by preparation method and application of catalyst

Info

Publication number: CN108238846B
Application number: CN201611219518.XA
Authority: CN
Inventors: 柴剑宇; 椿范立; 杨国辉; 李永烨
Original assignee: Highchem Co Ltd
Current assignee: Highchem Co Ltd
Priority date: 2016-12-26
Filing date: 2016-12-26
Publication date: 2021-07-27
Anticipated expiration: 2036-12-26
Also published as: WO2018121324A1; CN108238846A

Abstract

The present invention relates to a process for the preparation of a core/shell catalyst comprising: (A) 40-80% by weight of a composition comprising CuM of formula (I)_aO_xWherein the variables are as defined in the specification; and (B) a molecular sieve catalyst shell, the method of making comprising: impregnating copper-based catalyst particles with silica sol, and then coating a molecular sieve catalyst; or (b2) carrying out hydrothermal treatment on the silane coupling agent solution and the copper-based catalyst particles, then carrying out hydrothermal treatment on the silane coupling agent solution and the pure silicon molecular sieve, and finally carrying out hydrothermal treatment on the obtained roasted product by using a molecular sieve catalyst. The method not only can conveniently and successfully prepare the core/shell catalyst, but also can obtain improved dimethyl ether conversion rate and ethanol selectivity when the prepared catalyst is used for preparing ethanol by a one-step method of dimethyl ether and synthesis gas. The invention also relates to the core/shell catalyst prepared by the method and the application thereof as a catalyst in the one-step preparation of ethanol by dimethyl ether and synthesis gas.

Description

Preparation method of catalyst for ethanol synthesis, catalyst obtained by preparation method and application of catalyst

Technical Field

The invention relates to a method for preparing a catalyst for preparing ethanol by dimethyl ether and synthesis gas in one step, the catalyst prepared by the method and application of the catalyst.

Background

With the increasingly prominent problems of contradiction between supply and demand of global energy, environmental pollution and the like, the development of alternatives of fossil energy is urgently needed. Ethanol has received attention as a clean, efficient, renewable fuel. In addition, ethanol is an important basic raw material and has wide application in the aspects of medicines, chemical engineering and the like. The current ethanol production methods mainly comprise chemical synthesis methods and biological methods. The chemical synthesis method mainly refers to a method for preparing ethanol by ethylene catalytic hydration from a petroleum route, and the route has the defects of serious pollution, high energy consumption and the like. With the increasing exhaustion of petroleum resources, the competitiveness of chemical synthesis methods has declined year by year. The biological method is characterized in that ethanol is prepared by fermenting biomass, wherein non-petroleum energy biomass is used as a raw material, but the biomass mainly comprises plants such as corn, sugarcane and cassava, and is easy to cause global food shortage and price fluctuation. Therefore, the development of non-petroleum routes and non-food biomass routes for producing ethanol has important significance for reducing dependence on petroleum resources, reducing environmental pollution and the like.

Currently, syngas to ethanol is considered one of the most promising routes for ethanol production. Chinese patent CN1122567C discloses a two-step synthesis method of ethanol from syngas. First, synthesis gas was used to synthesize C over Rh-based catalyst₂Oxygenates, followed by Cu-based catalyst to ethanol. Chinese patent CN103537282B discloses a method for synthesizing ethanol and CO-producing methane by using synthesis gas, wherein Rh-based catalyst and Mn are used as auxiliary agents, the CO conversion rate reaches 20%, and the ethanol selectivity reaches 25%. The technical proposal uses a noble metal Rh catalyst, which has high price and high industrial production cost. In addition, the method has the technical bottlenecks of low carbon monoxide conversion rate, low ethanol selectivity and more byproducts.

In recent years, the team of the present inventors [ Energy & Fuels 23(2009)2843, Chem Sus Chem 3(2010), 1192] proposed a new route for producing ethanol from dimethyl ether and syngas (a mixture of carbon monoxide and hydrogen) as raw materials. Dimethyl ether can be converted from abundant coal resources, and synthetic gas can be produced from non-petroleum resources such as coal, natural gas, biomass and the like. This route provides a new non-petroleum route to ethanol. Ethanol is produced in the same reactor by adopting a double-layer catalyst filling method. Firstly, raw material gas passes through a molecular sieve catalyst layer, and dimethyl ether and carbon monoxide undergo carbonylation reaction to generate methyl acetate; then, methyl acetate is hydrogenated to generate main product ethanol and byproduct methanol through the copper-based catalyst layer. Wherein the conversion rate of dimethyl ether and the selectivity of ethanol can respectively reach 100 percent and 48 percent. The selectivity of the ethanol can reach 100 percent because the byproduct methanol can be recycled and dimethyl ether and water are further generated under the action of catalysts such as alumina or molecular sieve and the like. Therefore, the reaction is a green and environment-friendly ethanol production line with water as a main byproduct and without using a noble metal catalyst.

However, the two-stage packing of the catalyst for this reaction significantly reduces the space-time yield and is not suitable for industrial production. In addition, the filling mode of the upper and lower layers of catalysts limits the synergistic effect between active sites, thereby limiting the improvement of the activity of the catalysts; the molecular sieve catalyst has serious carbon deposition in the reaction process, reduces the service life of the catalyst and can not meet the industrial requirement.

Chinese patent application publication CN104801337A discloses a catalyst for preparing ethanol by dimethyl ether and synthesis gas in one step, which is a core-shell catalyst consisting of a Cu-based high-efficiency hydrogenation catalyst and various molecular sieves with eight-membered ring structures, wherein transition metal chlorides and nitrates of groups VIII, IB and IIB of the periodic table of elements are introduced into the Cu-based core catalyst as a cocatalyst; in order to obtain the core-shell catalyst, the core catalyst is directly added into the synthetic liquid of the shell molecular sieve, and the core-shell catalyst is obtained through hydrothermal crystallization. However, the preparation method is difficult to wrap the shell catalyst on the nuclear catalyst directly, and the yield is extremely low.

Disclosure of Invention

In view of the above-mentioned state of the art, the present inventors have conducted extensive and intensive studies on a core/shell catalyst for a one-step process of producing ethanol from dimethyl ether and syngas, in order to find a novel process for producing the core/shell catalyst for the one-step process of producing ethanol from dimethyl ether and syngas. The inventor finds that when the core/shell catalyst is prepared, a bonding layer is added between the core catalyst and the shell catalyst, so that the proportion of the shell catalyst in the core-shell capsule catalyst can be greatly increased. The "tie layers" are mainly divided into two categories: one is a solution of silica gel and the other is a combination of one or more silane coupling agents with one or more pure silica molecular sieves of the Silicalite series. The core/shell catalyst can be simply and successfully prepared by adding the bonding layer, and the catalyst prepared by the method can obtain improved dimethyl ether conversion rate and improved ethanol selectivity when used for preparing ethanol by using dimethyl ether and synthesis gas in one step. The present invention has been achieved based on the foregoing findings.

Accordingly, it is an object of the present invention to provide a process for the preparation of dimethyl ether and a core/shell catalyst for the one-step synthesis gas ethanol production. The method not only can simply and successfully prepare the core/shell catalyst, but also can obtain improved dimethyl ether conversion rate and improved ethanol selectivity when the catalyst prepared by the method is used for preparing ethanol by a one-step method of dimethyl ether and synthesis gas.

It is another object of the present invention to provide a core/shell catalyst prepared by the process of the present invention. When the catalyst is used for preparing ethanol by dimethyl ether and synthesis gas through one-step method, the improved conversion rate of dimethyl ether and the improved selectivity of ethanol can be obtained.

A final object of the present invention is to provide the use of the core/shell catalyst prepared by the process of the present invention as a catalyst in the one-step preparation of ethanol from dimethyl ether and synthesis gas. When the catalyst is used for preparing ethanol by one-step method of dimethyl ether and synthesis gas, the improved conversion rate of dimethyl ether and the improved selectivity of ethanol can be obtained.

The technical solution for achieving the above object of the present invention can be summarized as follows:

1. a process for the preparation of a core/shell catalyst for the one-step production of ethanol from dimethyl ether and synthesis gas, the catalyst comprising:

(A) the copper-based catalyst A comprising a compound of the formula (I) as core is present in an amount of from 40 to 80% by weight, preferably from 50 to 80%,

CuM_aO_b (I)

wherein

M is one or more elements selected from a second main group, a third main group and a transition element of the periodic table different from Cu, preferably one or more elements selected from Mg, Ca, Al, Ti, Mn, Co, Fe, Ni, Zn and Mo, and more preferably one or more elements selected from Zn, Al and Mn; a is a number between 0 and 30, preferably a number between 0 and 20, more preferably a number between 0 and 10, and particularly preferably a number between 1 and 8; and

b is a group satisfying the formula b

The number of oxygen atoms required for the valence of each element; and

(B) a molecular sieve catalyst B as a shell capable of catalyzing the carbonylation of dimethyl ether to form methyl acetate,

characterized in that the core/shell catalyst is prepared by a process comprising the steps of:

(a) providing particles of a copper-based catalyst a; and

(b1) impregnating particles of a copper-based catalyst A by using silica sol, then adding powder of a molecular sieve catalyst B to coat the impregnated copper-based catalyst particles, and then drying and roasting; or

(b2) Mixing a solution of a silane coupling agent with particles of a copper-based catalyst A, carrying out hydrothermal treatment for 1-24h at 50-200 ℃ in a hydrothermal reaction kettle, washing, drying, carrying out hydrothermal treatment for 1-24h at 50-200 ℃ in the hydrothermal reaction kettle by using a solution or a synthetic solution of a Silicalite series pure silicon molecular sieve, washing, drying, roasting, carrying out hydrothermal treatment for 1-96h at 100-300 ℃ on the obtained roasted product and a water dispersion or a synthetic solution of a molecular sieve catalyst B, washing, drying and roasting.

2. The process according to item 1, wherein the molecular sieve catalyst B comprises one or more metal elements Z selected from the group consisting of Fe, Co, Cu, Zn, Ru, Rh, Pd, Ag, Ir and Pt supported thereon.

3. The method according to item 1 or 2, wherein the silane coupling agent has the formula:

Y_aSiX_4-a (II)

wherein

a is an integer from 1 to 3, especially 1;

y are identical or different and independently of one another are vinyl, C₁-C₆Alkyl, chloro C₁-C₆Alkoxy, amino C₁-C₆Alkoxy, glycidyl ether oxygen C₁-C₆Alkyl, (methacryloyloxy) C₁-C₆Alkyl or N- (Amino group C₁-C₆Alkyl) amino C₁-C₆Alkyl, preferably Y is selected from vinyl, C₁-C₄Alkyl, chloro C₁-C₄Alkoxy, amino C₁-C₄Alkoxy, glycidyl ether oxygen C₁-C₄Alkyl, (methacryloyloxy) C₁-C₄Alkyl or N- (amino C)₁-C₄Alkyl) amino C₁-C₄An alkyl group; and

x are identical or different and independently of one another are OMe, OEt, OC₂H₄OCH₃、OSiMe₃Or OAc, preferably OMe or OEt,

preferably, the silane coupling agent is one or more selected from the group consisting of gamma-Aminopropyltriethoxysilane (APTES), gamma-Aminopropyltrimethoxysilane (APTMS), gamma-glycidoxypropyltrimethoxysilane, gamma- (methacryloyloxy) propyltrimethoxysilane, N- (2-aminoethyl) -3-aminopropyltrimethoxysilane and N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane.

4. The process according to any one of items 1 to 3, wherein the Silicalite series pure silica molecular sieves are one or more selected from the group consisting of Silicalite-1, MCM-41 and SBA-15.

5. The process according to any one of items 2 to 4, wherein the molecular sieve catalyst B is caused to contain the metal element Z in the following manner (i) or (ii),

(i) treating the molecular sieve catalyst B before coating or the core/shell catalyst calcined in the step (B1) or secondarily calcined in the step (B2) with an aqueous solution of a water-soluble precursor of the metal Z, drying and calcining, thereby loading the metal Z;

(ii) and (B) forming an aqueous dispersion by the copper-based catalyst A particles subjected to the second hydrothermal treatment in the step (B2), the molecular sieve catalyst B and water, or directly adding the copper-based catalyst A particles obtained by the second hydrothermal treatment into the synthesis solution of the molecular sieve catalyst B to obtain an aqueous dispersion, dissolving part of metal ions of the catalyst A particles into a liquid phase by adjusting the pH value of the obtained aqueous dispersion, then carrying out hydrothermal treatment on the aqueous dispersion in a hydrothermal reaction kettle at 100-300 ℃ for 1-96h, preferably at 150-250 ℃ for 24-72h, filtering, washing, drying and roasting to obtain the core/shell catalyst with one or more metals contained in the core doped in the shell layer.

6. A compound according to any one of items 1 to 5 wherein the molecular sieve catalyst B is one or more selected from H-MOR, H-ZSM-5, H-ZSM-35 and H- β, preferably H-MOR and/or H-ZSM-35.

7. The process according to any one of items 1 to 6, wherein the total amount of catalyst A and catalyst B is greater than 80%, preferably greater than 90%, based on the total weight of the core/shell catalyst.

8. The process according to any one of items 1 to 7, wherein the mass ratio of catalyst A to catalyst B is from 0.1 to 10, preferably from 0.5 to 5, more preferably from 1 to 5.

9. The process according to any one of items 1 to 8, wherein the copper-based catalyst A is prepared by:

(1) solid phase grinding method: grinding Cu salt and optional M salt together for 0.5-5 hr, and adding at least stoichiometric amount of NaOH and Na for precipitating Cu and M₂CO₃And NaHCO₃One or more of the above-mentioned materials are continuously ground for 0.5-6h, washed by deionized water to remove Na, dried for 5-24h at 50-150 deg.C, and roasted for 1-24h at 350-600 deg.C to obtain copper-based catalyst A;

(2) high-efficiency accurate precipitation method: preparing an aqueous solution A of a soluble Cu salt and optionally a soluble M salt, preparing a solution selected from NaOH, Na₂CO₃And NaHCO₃Adding the solution A and the solution B into a reactor by a pulse liquid phase pump respectively at a rate of ensuring that the pH value of a mixture formed by the added solution A and the added solution B in real time is 8-14, heating and stirring, keeping the heating temperature at 25-100 ℃, aging for 2-48h after the addition is finished, filtering out precipitates, washing with deionized water, drying for 5-24h at 50-150 ℃, and roasting for 1-24h at 600 ℃ of 350-; and

(3) ultrasonic isometric immersion method: preparing water solution of soluble Cu salt and optional soluble M salt, soaking the water solution on a porous carrier in the same volume under the action of ultrasonic wave, drying the obtained product in vacuum at 50-150 ℃ for 5-24h, and roasting at 350-600 ℃ for 1-24h to prepare the copper-based catalyst A.

10. A core/shell catalyst prepared by the method according to any one of items 1 to 9.

11. Use of a core/shell catalyst prepared by a process according to any one of claims 1 to 9 as a catalyst in the direct preparation of ethanol from dimethyl ether and synthesis gas.

These and other objects, features and advantages of the present invention will become readily apparent to those skilled in the art upon consideration of the following specification in conjunction with the invention.

Drawings

FIG. 1 is a schematic structural view of a core/shell catalyst prepared according to the process of the present invention, wherein M is a copper-based catalyst A and N is a molecular sieve catalyst B, wherein a bonding layer is present between the M and N layers.

Detailed Description

According to one aspect of the present invention there is provided a process for the preparation of dimethyl ether and a core/shell catalyst for a one-step synthesis gas process for the production of ethanol, the catalyst comprising:

(A) a copper-based catalyst A as a core, comprising a compound of the following formula (I), in an amount of 40 to 80% by weight, based on the total weight of the core/shell catalyst,

CuM_aO_b (I)

wherein

M is one or more elements selected from a second main group, a third main group and a transition element of the periodic table, which are different from Cu;

a is a number between 0 and 30; and

b is the number of oxygen atoms required to satisfy the valence of each element of formula (I); and

(a) providing particles of a copper-based catalyst a; and

The catalyst prepared by the method is a catalyst with a core/shell structure, is a composite catalyst, and can be used for preparing ethanol by one-step method by compounding dimethyl ether and synthesis gas. The shell of the core/shell catalyst is a molecular sieve with a carbonylation catalysis function, and can catalyze the carbonylation of dimethyl ether to form methyl acetate. The core of the core/shell catalyst is a copper-based catalyst for hydrogenation reactions, which is capable of hydrogenating esters to the corresponding alcohols. When the core/shell catalyst is used for preparing ethanol by dimethyl ether and synthesis gas, dimethyl ether serving as a reaction raw material firstly performs carbonylation reaction on an active site of a molecular sieve shell to generate methyl acetate, and then diffuses to the active site of a Cu-based core catalyst to perform hydrogenation reaction to generate ethanol, so that the ethanol can be prepared in one step. The core/shell catalyst of the present invention shortens the diffusion path of the two-step reaction and realizes the improvement of the reaction activity and the space-time rate. The core/shell catalyst has the advantages of high dimethyl ether conversion rate, high ethanol selectivity and long catalyst life when being used for preparing ethanol by a one-step method of dimethyl ether and synthesis gas, and has good application prospect.

The core of the core/shell catalyst of the present invention comprises a copper-based catalyst A of the compound of the following formula (I):

CuM_aO_b (I)

wherein M is one or more elements selected from the second main group, the third main group and the transition elements of the periodic table, which are different from Cu, and is preferably selected from Mg, Cu, and Cu,Ca. One or more elements of Al, Ti, Mn, Co, Fe, Ni, Zn and Mo, more preferably one or more elements of Zn, Al and Mn. a is the molar ratio of the element M to Cu. If M is two or more elements, a is the sum of the molar ratios of each of these elements to Cu. a is generally a number from 0 to 30, preferably a number from 0 to 20, more preferably a number from 0 to 10, and particularly preferably a number from 1 to 8. The copper-based catalyst A can be a supported catalyst or an unsupported catalyst. In the case of supported catalysts, the choice of support is conventional. The support may generally be selected from SiO₂、TiO₂、Al₂O₃、ZrO₂One or more of SiC, MgO and activated carbon. The content of the copper-based catalyst A is generally from 40 to 80% by weight, preferably from 50 to 80%, based on the total weight of the core/shell catalyst.

To prepare the core/shell catalysts of the present invention, it is generally necessary to first provide particles of copper-based catalyst a as the core and then coat molecular sieve catalyst B as the shell.

The particles of the copper-based catalyst A can be prepared in a conventional manner. According to the invention, the particles of the copper-based catalyst A are advantageously prepared by a solid-phase milling method, a highly efficient and precise precipitation method or an ultrasonic isovolumetric impregnation method.

Solid phase grinding method

In the solid phase milling method, the Cu salt and optionally the M salt are first milled together for 0.5 to 5 hours, and then at least a stoichiometric amount of NaOH, Na, selected from NaOH and Na, capable of precipitating Cu and M, is added₂CO₃And NaHCO₃One or more of the above-mentioned materials are continuously ground for 0.5-6h, then washed by deionized water to remove Na, dried at 50-150 deg.C for 5-24h, and roasted at 350-600 deg.C for 1-24h so as to obtain the copper-base catalyst A. The copper-based catalyst A is crushed to obtain particles of the copper-based catalyst A. As the Cu salt, copper nitrate, copper sulfate, copper chloride, or the like can be used. As the M salt, a nitrate, a sulfate, a chloride, or the like, for example, zinc nitrate, aluminum nitrate, or the like can be used. The M salt and the Cu salt are used in such amounts that the molar ratio of the M element to the Cu element is equal to a in the above formula (I). The drying in the solid-phase milling method is usually carried out at 50 to 150 ℃ and preferably at 60 to 120 ℃. The drying time is generally from 5 to 24 hours, preferably from 8 to 18 hours. Calcination in the solid phase milling method is generally carried out at 350-600 ℃, preferably at 350-500 ℃. The calcination time is generally from 1 to 24 hours, preferably from 1 to 10 hours. The average particle diameter of the particles of the copper-based catalyst A is usually 10 to 200 mesh, preferably 20 to 80 mesh.

High efficiency precision precipitation method

In the high-efficiency precise precipitation method, an aqueous solution A of soluble Cu salt and optional soluble M salt is prepared, and NaOH and Na are prepared₂CO₃And NaHCO₃Adding the solution A and the solution B into a reactor by a pulse liquid phase pump respectively at a rate of ensuring that the pH value of a mixture formed by the added solution A and the added solution B in real time is 8-14, heating and stirring, keeping the heating temperature at 25-100 ℃, aging for 2-48h after the addition is finished, filtering out precipitates, washing with deionized water, drying for 5-24h at 50-150 ℃, and roasting for 1-24h at 600 ℃ of 350-. The copper-based catalyst A is crushed to obtain particles of the copper-based catalyst A. As the soluble Cu salt, copper nitrate, copper sulfate, copper chloride, or the like can be used. As the soluble M salt, a nitrate, a sulfate, a chloride, or the like, for example, zinc nitrate, aluminum nitrate, or the like can be used. The soluble M salt and the soluble Cu salt are used in such amounts that the molar ratio of the M element to the Cu element is equal to a in the above formula (I). Solution a and solution B are typically added dropwise to the reactor. The addition rates of solution a and solution B should be such that: the pH of the mixture formed in real time from the solution A which has been added and the solution B which has been added is generally from 8 to 14, preferably from 8 to 10. When adding solution A and solution B, the mixture of solution A and solution B which has been added needs to be stirred and heated, the heating being such that the temperature of the resulting mixture is maintained generally between 25 and 100 ℃ and preferably between 40 and 90 ℃ during which precipitation occurs continuously. After the addition is complete, the reaction mixture is aged for 2 to 48h, preferably for 10 to 24 h. The precipitate was then filtered off and washed with deionized water. And then dried and calcined. The drying is generally carried out at from 50 to 150 ℃ and preferably at from 60 to 120 ℃. The drying time is generally from 5 to 24 hours, preferably8-18 h. Calcination is generally carried out at 350-600 deg.C, preferably at 350-500 deg.C. The calcination time is generally from 1 to 24 hours, preferably from 1 to 10 hours.

Ultrasonic equivoluminal dipping method

In an ultrasonic equivalent-volume impregnation method, preparing an aqueous solution of soluble Cu salt and optional soluble M salt, impregnating the aqueous solution on a porous carrier in an equivalent volume under the action of ultrasonic waves, drying the obtained product at 50-150 ℃ in vacuum for 5-24h, and roasting at 350-600 ℃ for 1-24h to prepare the copper-based catalyst A. The copper-based catalyst A is crushed to obtain particles of the copper-based catalyst A. As the soluble Cu salt, copper nitrate, copper sulfate, copper chloride, or the like can be used. As the soluble M salt herein, a nitrate, a sulfate, or a chloride, for example, zinc nitrate, aluminum nitrate, or the like can be used. The soluble M salt and the soluble Cu salt are used in such amounts that the molar ratio of the M element to the Cu element is equal to a in the above formula (I). After an aqueous solution of soluble Cu salt and optionally soluble M salt is prepared, the aqueous solution is immersed in equal volumes on a porous support under the action of ultrasound. An equal volume here means that the volume of the aqueous solution (i.e. the impregnation solution) used is the same as the pore volume of the support. The carrier is any carrier for copper-based catalyst suitable for ester hydrogenation to form corresponding alcohol, and comprises SiO₂、TiO₂、Al₂O₃、ZrO₂SiC, MgO, activated carbon, and the like. The frequency of the ultrasonic wave is usually more than or equal to 20 KHz. After ultrasonic equal-volume impregnation, drying and roasting. The drying is generally carried out at from 50 to 150 ℃ and preferably at from 60 to 120 ℃. The drying time is generally from 5 to 24 hours, preferably from 8 to 18 hours. Calcination is generally carried out at 350-600 deg.C, preferably at 350-500 deg.C. The calcination time is generally from 1 to 24 hours, preferably from 1 to 10 hours.

After providing the particles of the copper-based catalyst A, the particles of the copper-based catalyst A are coated with the molecular sieve catalyst B as a shell layer.

In order to coat the molecular sieve catalyst B as a shell layer, the invention discovers that the following two methods (namely the methods in the steps (B1) and (B2)) can successfully coat the molecular sieve catalyst B shell on the particles of the copper-based catalyst A, and the core/shell catalyst coated by the method can obtain high conversion rate of dimethyl ether and high ethanol yield when being used for preparing ethanol by a one-step method of dimethyl ether and synthesis gas, and has good stability and long service life.

In order to coat the molecular sieve catalyst B as a shell layer, the following method may be adopted:

(b1) the method comprises the following steps The particles of the copper-based catalyst A are impregnated with silica sol, and then the impregnated copper-based catalyst particles are coated with a powder of a molecular sieve catalyst B, followed by drying and calcination. This process may be referred to as a dip-then-stick process.

Silica sol is used as a binder in the present invention, and colloidal particles are firmly attached to the surface of an object as moisture in the silica sol evaporates. The concentration of the silica sol is usually 20 to 40% by weight. For the impregnation of the particles of the copper-based catalyst A, the amount of silica sol used is usually not less than the pore volume of the pores contained in the particles of the copper-based catalyst A. After the particles of the copper-based catalyst A are impregnated, the powder of the molecular sieve catalyst B is added, and the powder of the molecular sieve catalyst B is coated on the impregnated copper-based catalyst particles in an adhesion mode due to the existence of the adhesive. And then dried and calcined. The drying is generally carried out at from 50 to 150 ℃ and preferably at from 60 to 120 ℃. The drying time is generally from 5 to 24 hours, preferably from 8 to 18 hours. Calcination is generally carried out at 350-600 deg.C, preferably at 350-500 deg.C. The calcination time is generally from 1 to 24 hours, preferably from 1 to 10 hours.

As a method for coating the molecular sieve catalyst B, the following method may also be employed:

(b2) the method comprises the following steps Mixing a solution of a silane coupling agent with particles of a copper-based catalyst A, carrying out hydrothermal treatment for 1-24h at 50-200 ℃ in a hydrothermal reaction kettle, washing, drying, carrying out hydrothermal treatment for 1-24h at 50-200 ℃ in the hydrothermal reaction kettle by using a solution or a synthetic solution of a Silicalite series pure silicon molecular sieve, washing, drying, roasting, carrying out hydrothermal treatment for 1-96h at 100-300 ℃ on the obtained roasted product and a water dispersion of a molecular sieve catalyst B, washing, drying and roasting.

This process may be referred to as a hydrothermal synthesis process. The silane coupling agent is the same as the silane coupling agent in the moleculeOrganosilicon compounds containing two groups of different chemical nature, the classical products of which can be represented by the general formula Y_aSiX_4-aIn particular YSiX₃Wherein a is an integer of 1 to 3, Y is a non-hydrolyzable group including an alkenyl group (mainly vinyl group), and Cl, NH are terminated₂SH, epoxy group, N₃A hydrocarbon group of functional groups such as (meth) acryloxy, isocyanate, etc., i.e., a carbon functional group, and X is a hydrolyzable group including Cl, OMe, OEt, OC₂H₄OCH₃、OSiMe₃And OAc, etc. Due to the special structure of the silane coupling agent, the molecule of the silane coupling agent has a reaction group capable of being chemically combined with an inorganic material and a reaction group capable of being chemically combined with an organic material, so that the silane coupling agent can be used for surface treatment. It is preferred according to the invention that the silane coupling agent has the formula:

Y_aSiX_4-a (II)

wherein a is an integer from 1 to 3, in particular 1, Y are identical or different and are, independently of one another, vinyl, C₁-C₆Alkyl, chloro C₁-C₆Alkoxy, amino C₁-C₆Alkoxy, glycidyl ether oxygen C₁-C₆Alkyl, (methacryloyloxy) C₁-C₆Alkyl or N- (amino C)₁-C₆Alkyl) amino C₁-C₆Alkyl, and X are identical or different and independently of one another are OMe, OEt, OC₂H₄OCH₃、OSiMe₃Or an OAc. As silane coupling agents of the formula (II), preference is given to Y being identical or different and independently of one another being vinyl, C₁-C₄Alkyl, chloro C₁-C₄Alkoxy, amino C₁-C₄Alkoxy, glycidyl ether oxygen C₁-C₄Alkyl, (methacryloyloxy) C₁-C₄Alkyl or N- (amino C)₁-C₄Alkyl) amino C₁-C₄An alkyl group; and/or X are the same or different and independently of each other OMe or OEt. As examples of the silane coupling agent of the present invention, there may be mentioned: gamma-Aminopropyltriethoxysilane (APTES), gamma-Aminopropyltrimethoxysilane (APTMS), gamma-glycidyloxy-trimethoxysilane (APTMS)Glycerol ether oxygen propyl trimethoxy silane, gamma- (methacryloyloxy) propyl trimethoxy silane, N- (2-aminoethyl) -3-aminopropyl trimethoxy silane

And N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane

The solvent used for the silane coupling agent solution is typically water, alcohol or a mixture of water and alcohol. The concentration of the silane coupling agent solution is usually 0.2 to 5% by weight. The amount of the silane coupling agent solution used is usually equal to or greater than the pore volume of the pores contained in the particles of the copper-based catalyst A. After mixing the particles of the copper-based catalyst A with the silane coupling agent solution, carrying out hydrothermal treatment for 1-24h at 50-200 ℃ in a hydrothermal reaction kettle, preferably for 5-12h at 80-150 ℃ in the hydrothermal reaction kettle, and then washing and drying. Washing is typically with deionized water. The drying is generally carried out at from 50 to 150 ℃ and preferably at from 60 to 120 ℃. The drying time is generally from 5 to 24 hours, preferably from 8 to 18 hours. Drying to obtain copper-based catalyst A particles after first hydrothermal treatment, then carrying out hydrothermal treatment on the copper-based catalyst A particles for 1-24h by using a water solution or a synthetic solution of a Silicalite series pure silicon molecular sieve in a hydrothermal reaction kettle at 50-200 ℃, washing, drying and roasting. The Silicalite-series pure silica molecular sieves referred to herein are silicon-only molecular sieves. As the pure silica molecular sieve of the Silicalite series, Silicalite-1, MCM-41, SBA-15 and the like can be mentioned. The aqueous solutions of pure Silicalite series molecular sieves are typically commercial or self-made solutions of pure Silicalite series molecular sieves in water, alcohols or hydroalcoholic mixtures, typically at concentrations of 0.1 to 2% by weight. The amount of this solution used is generally equal to or greater than the pore volume of the pores contained in the particles of catalyst A. The synthetic solution of the Silicalite series pure silicon molecular sieve is a synthetic solution (namely, a liquid mixture before hydrothermal synthesis of the molecular sieve) obtained by preparing a corresponding molecular sieve by a conventional method. The synthesis method and conditions of the molecular sieve are mature and are easy to obtain.

After the Silicalite series pure silicon molecular sieves are wrapped on the outer layer of the core of the copper-based catalyst A, the Silicalite series pure silicon molecular sieves can play a role of crystal seeds in the process of synthesizing a shell catalyst, and are easy to synthesize the shell. After the solution or the synthetic solution of the Silicalite series molecular sieve is mixed with the copper-based catalyst A particles subjected to the first hydrothermal treatment, the mixture is subjected to hydrothermal treatment for 1 to 24 hours at 50 to 200 ℃ in a hydrothermal reaction kettle, preferably for 4 to 12 hours at 80 to 180 ℃ in the hydrothermal reaction kettle, and then the mixture is washed, dried and roasted to obtain the copper-based catalyst A particles subjected to the second hydrothermal treatment. Washing is typically with deionized water. The drying is generally carried out at from 50 to 150 ℃ and preferably at from 60 to 120 ℃. The drying time is generally from 5 to 24 hours, preferably from 8 to 18 hours. Calcination is generally carried out at 350-600 deg.C, preferably at 350-500 deg.C. The calcination time is generally from 1 to 24 hours, preferably from 1 to 10 hours.

And then, forming an aqueous dispersion by the copper-based catalyst A particles subjected to the second hydrothermal treatment, the molecular sieve catalyst B and water together, or directly adding the copper-based catalyst A particles subjected to the second hydrothermal treatment into the synthesis solution of the molecular sieve catalyst B to form an aqueous dispersion, carrying out hydrothermal treatment on the aqueous dispersion in a hydrothermal reaction kettle at 100-300 ℃ for 1-96h, preferably at 150-250 ℃ for 24-72h, washing, drying and roasting to obtain the core/shell catalyst. Washing is typically with deionized water. The drying is generally carried out at from 50 to 150 ℃ and preferably at from 60 to 120 ℃. The drying time is generally from 5 to 24 hours, preferably from 8 to 18 hours. Calcination is generally carried out at 350-600 deg.C, preferably at 350-500 deg.C. The calcination time is generally from 1 to 24 hours, preferably from 4 to 10 hours.

Because the shell molecular sieve has catalytic activity only when the shell is H-type, if the shell is Na or other ionic molecular sieve, the shell is also converted into H-type by ion exchange. This may typically operate, for example, as follows: adding the Na-type molecular sieve into 1M ammonium nitrate aqueous solution, stirring for 2-12H at 80 ℃, filtering, washing, drying and roasting to obtain the core/shell catalyst with the H-type molecular sieve shell layer. The drying is generally carried out at from 50 to 150 ℃ and preferably at from 60 to 120 ℃. The drying time is generally from 5 to 24 hours, preferably from 8 to 18 hours. Calcination is generally carried out at 350-600 deg.C, preferably at 350-550 deg.C. The calcination time is generally from 1 to 24 hours, preferably from 4 to 10 hours.

The molecular sieve catalyst B as the shell of the core/shell catalyst is a molecular sieve with carbonylation catalysis function and can catalyze the carbonylation of dimethyl ether to form methyl acetate. Preferably, the molecular sieve catalyst B is one or more selected from H-MOR, H-ZSM-5, H-ZSM-35 and H-beta, especially H-MOR and/or H-ZSM-35.

In a preferred embodiment of the present invention, molecular sieve catalyst B comprises one or more metal elements selected from Fe, Co, Cu, Zn, Ru, Rh, Pd, Ag, Ir and Pt (hereinafter referred to as metal Z) supported thereon, which may be present as an elemental substance, as a compound such as an oxide, or as a mixture of an elemental substance and a compound thereof. The inclusion of the metal Z enhances the anti-carbon deposition ability of the core/shell catalyst of the present invention, thereby extending the catalyst life. The content of the metal Z, calculated as element, is generally from 0 to 10% by weight, preferably from 1 to 6% by weight, based on the total weight of the shell of the core/shell catalyst

In order for molecular sieve catalyst B to contain the metal element Z, it can be achieved by the following means (i) or (ii):

(i) the molecular sieve catalyst B before coating or the core/shell catalyst calcined in step (B1) or twice calcined in step (B2) is treated with an aqueous solution of a water-soluble precursor of metal Z, dried and calcined, thereby supporting the metal Z. The supporting method of the metal Z includes an impregnation method, an ion exchange method, and the like. The impregnation method is generally: preparing an aqueous solution of a water-soluble precursor of the metal Z in deionized water, soaking the aqueous solution in the molecular sieve catalyst B in the same volume or on the core/shell catalyst obtained by roasting in the step (B1) or obtained by secondary roasting in the step (B2), drying and roasting. The equal volume herein means that the volume of the impregnating solution is equal to the pore volume of the pores contained in the molecular sieve catalyst B or the core/shell catalyst calcined in step (B1) or twice calcined in step (B2). The drying is generally carried out at from 50 to 150 ℃ and preferably at from 60 to 120 ℃. The drying time is generally from 5 to 24 hours, preferably from 8 to 18 hours. Calcination is generally carried out at 350-600 deg.C, preferably at 350-500 deg.C. The calcination time is usually 1 to 24 hoursPreferably 1-10 h. As the water-soluble precursor of the metal Z here, a water-soluble salt of the metal Z can be mentioned, and a nitrate, a sulfate, a chloride or the like, for example, copper nitrate, platinum nitrate, ruthenium chloride or the like can be used. The ion exchange method is a commonly used catalyst preparation method, and particularly utilizes cations (such as Na) in the molecular sieve in the aspect of metal modification of the molecular sieve⁺，NH₄ ⁺) With cations (ions to be exchanged, e.g. Cu) in solution²⁺，Zn²⁺) To achieve ion exchange. The common practice is: preparing a solution of a water-soluble precursor (such as a water-soluble salt) of the metal Z, adding a sample to be loaded (the molecular sieve catalyst B before coating or the core/shell catalyst obtained by roasting in the step (B1) or the core/shell catalyst obtained by secondary roasting in the step (B2)), stirring and keeping the temperature at 60-100 ℃, preferably 60-80 ℃, and performing suction filtration, drying and roasting after the exchange is finished. The drying is generally carried out at from 50 to 150 ℃ and preferably at from 60 to 120 ℃. The drying time is generally from 5 to 24 hours, preferably from 8 to 18 hours. Calcination is generally carried out at 350-600 deg.C, preferably at 350-500 deg.C. The calcination time is generally from 1 to 24 hours, preferably from 1 to 10 hours.

(ii) And (B) forming an aqueous dispersion by the copper-based catalyst A particles subjected to the second hydrothermal treatment in the step (B2), the molecular sieve catalyst B and water, or directly adding the copper-based catalyst A particles obtained by the second hydrothermal treatment into the synthesis solution of the molecular sieve catalyst B to obtain an aqueous dispersion, dissolving part of metal ions of the catalyst A particles into a liquid phase by adjusting the pH value of the obtained aqueous dispersion, then carrying out hydrothermal treatment on the aqueous dispersion in a hydrothermal reaction kettle at 100-300 ℃ for 1-96h, preferably at 150-250 ℃ for 24-72h, filtering, washing, drying and roasting to obtain the core/shell catalyst with one or more metals contained in the core doped in the shell layer. The pH here is generally from 7 to 13, preferably from 8 to 12. Washing is typically with deionized water. The drying is generally carried out at from 50 to 150 ℃ and preferably at from 60 to 120 ℃. The drying time is generally from 5 to 24 hours, preferably from 8 to 18 hours. Calcination is generally carried out at 350-600 deg.C, preferably at 350-500 deg.C. The calcination time is generally from 1 to 24 hours, preferably from 1 to 10 hours.

In the core/shell catalyst of the present invention, the mass ratio of the catalyst A to the catalyst B is 0.1 to 10, preferably 0.5 to 5, more preferably 1 to 5. The total amount of catalyst a and catalyst B is greater than 80%, preferably greater than 90%, based on the total weight of the core/shell catalyst.

The core/shell catalyst of the present invention has an average particle diameter of 10 to 200 mesh, preferably 12 to 60 mesh.

According to another aspect of the present invention, there is provided a core/shell catalyst made by the process of the present invention. All features of the core/shell catalyst are the same as described above for the preparation of the core/shell catalyst.

According to a final aspect of the invention there is provided the use of a core/shell catalyst prepared by the process of the invention in the direct production of ethanol from dimethyl ether and synthesis gas.

Before the core/shell catalyst is used for directly preparing ethanol by dimethyl ether and synthesis gas, if Cu and optional M in the copper-based catalyst and optional metal Z contained in the molecular sieve catalyst B are not in an elemental form, the core/shell catalyst needs to be reduced so that the elements in the catalyst are in an elemental form. For this purpose, the core/shell catalyst is usually reduced with an atmosphere containing hydrogen. The reduction temperature is usually 200-500 deg.C, preferably 200-300 deg.C. The reduction pressure is usually 0 to 10MPa, preferably 0 to 5MPa, gauge. The reduction time is generally from 5 to 24h, preferably from 5 to 12 h. The reducing atmosphere may be pure hydrogen or a mixture of hydrogen and CO. Thus, CO: H₂The molar ratio is usually from 0 to 10, preferably from 0 to 5. The reduction space velocity is usually 500-50000h^-1Preferably 500-^-1. After reduction, Cu and optionally M in the copper-based catalyst in the core/shell catalyst and optionally the metal Z element contained in the molecular sieve catalyst B are in elemental form and exhibit catalytic activity.

When the core/shell catalyst is used for directly preparing ethanol by dimethyl ether and synthesis gas, the reaction can be carried out intermittently or continuously. The catalyst may be used in any conventional form, preferably in the form of a fixed bed. When the core/shell catalyst is used for directly preparing ethanol by dimethyl ether and synthesis gas, Ar (argon), DME, CO and H are contained₂By the reaction stream comprisingThe invention relates to a reactor of a core/shell catalyst. The reaction temperature is usually 200-500 deg.C, preferably 200-300 deg.C. The reaction pressure is usually 0 to 10MPa, preferably 0.5 to 5MPa, gauge. The reaction time is generally from 0.5 to 20 hours, preferably from 0.5 to 10 hours. The reaction space velocity is usually 500-50000h^-1Preferably 500-^-1. Molar ratio of reaction gas: ar DME CO H₂(1) (0.1-20): (0.1-50): 0.1-50), preferably 1 (0.1-10): 10-50), wherein Ar is an internal standard and DME is dimethyl ether.

Examples

The present invention will be further described with reference to the following specific examples, which should not be construed as limiting the scope of the invention.

Example 1

Preparation of the catalyst

0.1mol of copper nitrate and 0.1mol of zinc nitrate are weighed, ground in an agate mortar for 0.5h, added with 0.2mol of sodium carbonate and continuously ground for 2 h. Washing the obtained sample with deionized water, drying at 100 deg.C for 10 hr, calcining at 350 deg.C for 3 hr, and press-forming into 20-40 mesh granule. 0.5g of the obtained particles are put into 0.5g of 30 wt% silica sol for full infiltration, then commercial powder molecular sieve H-MOR (Tosoh corporation) is added, after uniform stirring, drying is carried out for 6H at 100 ℃, and roasting is carried out for 5H at 500 ℃, thus obtaining the CuZnO @ S @ H-MOR core/shell catalyst, wherein CuZnO is a core, H-MOR is a shell, S is an adhesive layer (silica sol) connecting the core and the shell, the core accounts for 80% of the total weight of the core/shell catalyst, and the total weight of the core and the shell accounts for 90% of the total weight of the core/shell catalyst.

Reduction and reaction of catalyst

Weighing 0.5g of the obtained core/shell catalyst, placing into a tubular fixed bed reactor with an inner diameter of 8mm, vertically placing, filling quartz wool at two ends of the catalyst bed, and introducing 100% H with flow rate of 30mL/min from one end₂After 10 hours of reduction at 300 ℃ and atmospheric pressure, the gas was then switched to a reaction gas containing the following components in the following molar ratios: ar DME CO H₂The reaction is started at the reaction temperature of 220 ℃ and the total gas pressure of 1.5MPa (gauge pressure) at the flow rate of 40mL/min, the reaction is continuously carried out, and the reactant conversion rate and the product selectivity are measured and calculated in real time. The results are shown in Table 1.

Example 2

Preparing 1M ammonia water solution B by using deionized water; 0.1mol of copper nitrate, 0.05mol of zinc nitrate and 0.05mol of aluminum nitrate are weighed and prepared into an aqueous solution A by deionized water. The prepared solution A and the prepared solution B are respectively dripped into the same beaker by a pulse liquid phase pump, the dripping speed of the two solutions is controlled at the same time, the pH value of the mixed solution obtained in real time is accurately controlled to be 10, the temperature of the mixed solution is kept to be 50 ℃, stirring is kept during the feeding process, meanwhile, precipitation is generated, and the dripping of the solution B is stopped after the dripping of the solution A is finished. After the addition, the obtained precipitation mixture is aged for 12h, filtered, washed by deionized water, dried for 10h at 120 ℃, roasted for 3h at 350 ℃, and pressed and formed into particles with 20-40 meshes. Then, 0.5g of the obtained granules was thoroughly impregnated with 1g of 30 wt% silica sol, followed by addition of commercial powder molecular sieve H-MOR (Tosoh corporation), followed by uniform stirring, drying at 100 ℃ for 6 hours and calcination at 500 ℃ for 5 hours. The following ion exchange was then performed: adding 1g of roasted sample into 50mL of 0.2M copper nitrate aqueous solution, stirring and keeping the temperature at 80 ℃, performing suction filtration after 2h, drying at 100 ℃ for 6h, and roasting at 500 ℃ for 2 h; repeating the ion exchange step for 4 times to obtain CuZn_0.5Al_0.5O_2.25@S@Cu₅H-MOR "core/shell catalyst, in which CuZn_0.5Al_0.5O_2.25As a nucleus, Cu₅H-MOR is the shell, "Cu₅"means that the Cu content of the shell relative to the shell is 5 wt%. S is a bonding layer (silica sol) connecting the core and the shell, the core accounting for 70% of the total weight of the core/shell catalyst, and the total weight of the core and the shell accounting for 90% of the total weight of the core/shell catalyst.

The reduction and reaction of the catalyst in example 1 were repeated and the results are shown in table 1.

Example 3

0.1mol of copper nitrate and 0.1mol of zinc nitrate are weighed, deionized water is used for preparing 30mL of aqueous solution, and the aqueous solution is immersed in 0.5mol of SiO under the assistance of ultrasonic waves (20KHz)₂Vacuum drying the carrier at 50 deg.C for 24 hr, calcining at 350 deg.C for 4 hr, and press-forming to obtain 20-40 mesh granules. 0.5g of the resulting particles were then added to a 0.3 wt% ethanol solution of 0.5g of the silane coupling agent APTMS (Aldrich) in a hydrothermal reactor at 80 deg.CThe mixture was subjected to hydrothermal treatment for 12 hours, washed with deionized water, dried at 100 ℃ for 10 hours, and then added with a 1 wt% aqueous solution of a commercial Silicalite-1 molecular sieve (Tosoh Corp.), subjected to hydrothermal treatment at 100 ℃ for 12 hours in a hydrothermal reactor, washed with deionized water, dried at 100 ℃ for 10 hours, and then calcined at 450 ℃ for 5 hours. Adding the obtained calcined substance into synthetic solution (1.85 Na) of H-ZSM-35₂O： 1Al₂O₃：20SiO₂：592H₂O: 19.7pyrrolidine), carrying out hydrothermal treatment for 72h at 200 ℃ in a hydrothermal reaction kettle, filtering, washing by deionized water, drying for 10h at 100 ℃, and roasting for 3h at 550 ℃ to obtain the core/shell catalyst with a shell catalyst of Na-type molecular sieve. The preparation of the aforementioned synthetic solution was as follows: weighing 1.16g NaAlO₂Dissolved in 60mL of 0.5M NaOH aqueous solution and marked as solution A; 29.68g of 30 wt% silica sol was weighed in, 10.21g of pyrrolidine was added, and the resulting solution was designated as solution B; uniformly mixing the solution A and the solution B to obtain a synthetic solution (1.85 Na)₂O：1Al₂O₃：20SiO₂：592H₂O: 19.7 pyrrolidine).

And then, carrying out ion exchange on the Na-type molecular sieve serving as the shell catalyst to obtain the H-type molecular sieve. The method specifically comprises the following steps: weighing 1g of the obtained core/shell catalyst sample, adding the core/shell catalyst sample into 1M ammonium nitrate aqueous solution, stirring for 6H at 80 ℃, filtering, washing with deionized water, drying for 10H at 100 ℃, and roasting for 3H at 550 ℃ to obtain the core/shell catalyst with the shell catalyst being the H-type molecular sieve.

And then, loading Pt in the shell layer of the core/shell catalyst by adopting an impregnation method. Specifically, 2g of the core/shell catalyst having an H-type molecular sieve as a shell catalyst was impregnated with 2g of Pt (NH)₃)₂(NO₂)₂In the water solution of deionized water, the Pt content in the water solution is 0.005 wt%, filtering, drying at 100 ℃ for 12h, and roasting at 500 ℃ for 5h to obtain CuZn₁Si₅O₁₂@S@Pt₁H-ZSM-35 "core/shell catalyst, in which CuZn₁Si₅O₁₂As nuclei, Pt₁H-ZSM-35 as shell, "Pt₁"means that the Pt content relative to the shell is 1 wt%, S is a tie layer (APTMS and Silicalite-1) connecting the core and the shell, the core accounts for 50% of the total weight of the core/shell catalyst, and the coreAnd the total weight of the shell represents 92% of the total weight of the core/shell catalyst.

The reduction and reaction of the catalyst in example 1 were repeated using the obtained core/shell catalyst, and the results are shown in table 1.

Example 4

The catalyst preparation procedure was essentially the same as in example 3, except that: in example 3, the calcined product obtained by hydrothermal treatment, washing, drying and calcination using an aqueous solution of a commercial Silicalite-1 molecular sieve was added to a synthetic solution of H-ZSM-35 (1.85 Na)₂O：1Al₂O₃：20SiO₂：592H₂O: 19.7pyrrolidine), controlling the pH value of the aqueous dispersion to 10 by adopting 0.02M NaOH aqueous solution, dissolving partial ions of the core catalyst into a liquid phase, then carrying out hydrothermal treatment for 72h at 200 ℃ in a hydrothermal reaction kettle, filtering, washing by deionized water, drying for 10h at 100 ℃, and roasting for 3h at 550 ℃ to obtain the core/shell catalyst of which the shell catalyst is a Na-type molecular sieve.

Then, as described in example 3, Na-type molecular sieve as shell catalyst is ion exchanged to obtain H-type molecular sieve, and "CuZn" is obtained₁Si₅O₁₂@S@Cu₅H-ZSM-35 "core/shell catalyst, in which CuZn₁Si₅O₁₂As a nucleus, Cu₅H-ZSM-35 as shell, "Cu₅"means that the shell has a Cu content of 5 wt% relative to the shell, S is a tie layer (APTMS and Silicalite-1) connecting the core to the shell, the core comprises 50% of the total weight of the core/shell catalyst, and the total weight of the core and shell comprises 88% of the total weight of the core/shell catalyst.

Example 5

The catalyst preparation process was essentially the same as in example 2, except that: the Cu loading step of the shell catalyst in example 2 was omitted to obtain "CuZn_0.5Al_0.5O_2.25@ S @ H-MOR "core/shell catalyst, in which CuZn_0.5Al_0.5O_2.25Is a core, H-MOR is a shell, S is a bonding layer (silica sol) connecting the core and the shell, the core accounts for 70 percent of the total weight of the core/shell catalyst, the core andthe total weight of the shell represents 93% of the total weight of the core/shell catalyst.

Example 6

The catalyst preparation procedure was essentially the same as in example 3, except that: the hydrothermal treatment with the commercial Silicalite-1 molecular sieve in example 3 was changed to a hydrothermal treatment with a commercial MCM-41 molecular sieve. Finally obtaining' CuZn₁Si₅O₁₂@S@Pt₁H-ZSM-35 "core/shell catalyst, in which CuZn₁Si₅O₁₂As nuclei, Pt₁H-ZSM-35 as shell, "Pt₁"means that the Pt content relative to the shell layer is 1 wt%, S is a bonding layer (APTMS and MCM-41) connecting the core and the shell, the core represents 50% of the total weight of the core/shell catalyst, and the total weight of the core and the shell represents 92% of the total weight of the core/shell catalyst.

Example 7

The catalyst preparation procedure was essentially the same as in example 3, except that: 1) 0.1mol of zinc nitrate used in the preparation of the nuclear catalyst in example 3 was replaced with 0.05mol of iron nitrate +0.05mol of cobalt nitrate; 2) the silane coupling agent used before coating, aptms (aldrich), was replaced with aptes (aldrich); and 3) Pt modification in the shell is replaced by Rh modification, namely Pt (NH)₃)₂(NO₂)₂The aqueous solution in deionized water was replaced with 2g Rh (NO)₃)₃An aqueous solution in deionized water having an Rh content of 0.005 wt%. Finally obtaining' CuFe_0.5Co_0.5Si₅O₁₂@S@Rh₁H-ZSM-35 "core/shell catalyst, in which CuFe_0.5Co_0.5Si₅O₁₂As nuclei, Rh₁H-ZSM-35 as shell, "Rh₁"means that Rh content relative to the shell layer was 1 wt%, S was a tie layer (APTES and Silicalite-1) connecting the core to the shell, the core accounted for 60% of the total weight of the core/shell catalyst, and the total weight of the core and shell accounted for 86% of the total weight of the core/shell catalyst.

Example 8

The catalyst preparation procedure was essentially the same as in example 3, except that: 1) 0.1mol of zinc nitrate used for preparing the nuclear catalyst in example 3 was replaced with 0.05mol of nickel nitrate +0.025mol of manganese nitrate +0.025mol of magnesium nitrate; 2) replacing the silane coupling agent APTMS (Aldrich) used before coating with gamma-glycidoxypropyltrimethoxysilane (Aldrich); and 3) replacing the commercial Silicalite-1 molecular sieve with the commercial SBA-15 molecular sieve. Finally obtaining' CuNi_0.5Mn_0.25Mg_0.25Si₅O₁₂@S@Pt₁H-ZSM-35 "core/shell catalyst, in which CuNi_0.5Mn_0.25Mg_0.25Si₅O₁₂As nuclei, Pt₁H-ZSM-35 as shell, "Pt₁"means that the Pt content relative to the shell layer is 1 wt%, S is the bonding layer (gamma-glycidoxypropyltrimethoxysilane and SBA-15) connecting the core to the shell, the core represents 70% of the total weight of the core/shell catalyst, and the total weight of the core and shell represents 85% of the total weight of the core/shell catalyst.

Example 9

Example 3 was repeated, except that: the reaction time for directly preparing ethanol by dimethyl ether and synthesis gas is prolonged to 40 hours, and the reaction result is shown in table 1.

Example 10

Example 3 was repeated, except that: the reaction pressure of the reaction for directly preparing ethanol by dimethyl ether and synthesis gas is changed to 0.5MPa, and the reaction result is shown in Table 1.

Comparative example 1

The catalyst was prepared essentially as in example 1, except that the amount of catalyst core was varied such that the resulting catalyst had a core comprising 90% of the total weight of the core/shell catalyst and a total weight of the core and shell comprising 95% of the total weight of the core/shell catalyst.

The resulting catalyst was applied to the dimethyl ether and syngas direct ethanol production as described in example 1 and the results are shown in table 1.

Comparative example 2

The catalyst was prepared essentially as in example 2, except that the amounts of zinc nitrate and aluminum nitrate were varied to give a catalyst having the composition: "CuZn₂₀Al₂₀O₅₁@ S @ CuH-MOR "core/shell catalyst, wherein CuZn₂₀Al₂₀O₅₁The core is CuH-MOR, the shell is CuH-MOR, the Cu content in the shell is 5%, S is a bonding layer (silica sol) for connecting the core and the shell, the core accounts for 70% of the total weight of the core/shell catalyst, and the total weight of the core and the shell accounts for 90% of the total weight of the core/shell catalyst.

The resulting catalyst, the resulting/shell catalyst, was applied to the reaction of dimethyl ether with syngas to produce ethanol directly as described in example 1, and the results are shown in table 1.

Comparative example 3

The catalyst was prepared in a manner similar to that of example 1 except that the step of impregnating silica sol was changed to impregnation water, and then wet copper-based catalyst particles A (20-40 mesh particles) were directly mixed with commercial powder molecular sieve H-MOR (Tosoh corporation), uniformly stirred, dried at 100 ℃ for 6 hours, and calcined at 500 ℃ for 5 hours, and the calcined product obtained did not have a core/shell structure.

The calcined product was used in the reaction of dimethyl ether with syngas to produce ethanol directly as described in example 1, and the results are shown in table 1.

Comparative example 4

The catalyst preparation was similar to example 3, except that: the hydrothermal treatment step using APTMS was omitted by adding the press-formed 20-40 mesh particles A directly to a 1 wt% solution of a commercial Silicalite-1 molecular sieve (Tosoh Corp.) and then performing the same operation as in example 3 to obtain "CuZn₁Si₅O₁₂@S@Pt₁H-ZSM-35 "core/shell catalyst, in which CuZn₁Si₅O₁₂As nuclei, Pt₁H-ZSM-35 as shell, "Pt₁"means that the Pt content relative to the shell layer is 1 wt%, S is a binding layer (Silicalite-1) connecting the core and the shell, the core represents 50% of the total weight of the core/shell catalyst, and the total weight of the core and the shell represents 90% of the total weight of the core/shell catalyst.

COMPARATIVE EXAMPLE 5 (without adhesive layer)

The catalyst preparation was similar to example 3, except that: omitting the hydrothermal treatment with silane coupling agent APTMS and commercial Silicalite-1 molecular sieves, i.e., copper-based catalyst particles (i.e., press-formed 20-40 mesh particles A) were added directly to the synthesis solution (1.85 Na) of H-ZSM-35₂O：1Al₂O₃： 20SiO₂：592H₂O: 19.7Pyrrolidine), followed by exactly the same procedure as in example 3 gave "CuZn₁Si₅O₁₂@Pt₁H-ZSM-35 "core/shell catalyst, in which CuZn₁Si₅O₁₂As nuclei, Pt₁H-ZSM-35 as shell, "Pt₁"means that the Pt content relative to the shell layer is 1 wt%, the core represents 90% of the total weight of the core/shell catalyst, and the total weight of the core and shell represents 100% of the total weight of the core/shell catalyst. The catalyst is applied to the reaction of directly preparing ethanol by dimethyl ether and synthesis gas, and the result is shown in table 1.

TABLE 1

The activity evaluation conditions of the above catalysts were as follows:

the reduction conditions for examples 1-8 and comparative examples 1-5 were: 300 ℃, 0.1MPa and 1000h^-1、 CO:H₂0: 1; the reaction conditions are as follows: 220 ℃, 4h, 1.5MPa and 1000h^-10.5g of catalyst, Ar: DME: CO: H₂＝1:1:48:50；

The reduction conditions of example 9 were the same as above, but the reaction time was extended to 40h in the reaction conditions.

The reduction conditions of example 10 were as above, but the pressure in the reaction conditions was 0.5MPa, and the other conditions were as above.

Claims

CuM_aO_b (I)

wherein

M is one or more elements selected from a second main group, a third main group and transition elements of the periodic table, which are different from Cu;

a is a number between 0 and 30; and

(a) providing particles of a copper-based catalyst a; and

2. The process according to claim 1, wherein the copper-based catalyst A is present in an amount of from 50 to 80%, based on the total weight of the core/shell catalyst.

3. The method according to claim 1, wherein M is one or more elements selected from the group consisting of Mg, Ca, Al, Ti, Mn, Co, Fe, Ni, Zn and Mo.

4. The method according to claim 1, wherein M is one or more elements of Zn, Al and Mn.

5. The method of claim 1, a is a number between 0 and 20.

6. The method of claim 1, a is a number between 0 and 10.

7. The process according to claim 1, a is a number from 1 to 8.

8. The process according to any one of claims 1 to 7, wherein the molecular sieve catalyst B comprises one or more metal elements Z selected from the group consisting of Fe, Co, Cu, Zn, Ru, Rh, Pd, Ag, Ir and Pt supported thereon.

9. The method of any of claims 1-7, wherein the silane coupling agent has the formula:

Y_aSiX_4-a (II)

wherein

a is an integer of 1 to 3;

y are identical or different and independently of one another are vinyl, C₁-C₆Alkyl, chloro C₁-C₆Alkoxy, amino C₁-C₆Alkoxy, glycidyl ether oxygen C₁-C₆Alkyl, (methacryloyloxy) C₁-C₆Alkyl or N- (amino C)₁-C₆Alkyl) amino C₁-C₆An alkyl group; and

x are identical or different and independently of one another are OMe, OEt, OC₂H₄OCH₃、OSiMe₃Or an OAc.

10. The method according to claim 9, wherein a is 1.

11. The process according to claim 9, wherein Y is selected from vinyl, C₁-C₄Alkyl, chloro C₁-C₄Alkoxy, amino C₁-C₄Alkoxy, glycidyl ether oxygen C₁-C₄Alkyl, (methacryloyloxy) C₁-C₄Alkyl or N- (amino C)₁-C₄Alkyl) amino C₁-C₄An alkyl group.

12. The process of claim 9 wherein X is OMe or OEt.

13. The method according to claim 9, wherein the silane coupling agent is one or more selected from the group consisting of γ -Aminopropyltriethoxysilane (APTES), γ -Aminopropyltrimethoxysilane (APTMS), γ -glycidoxypropyltrimethoxysilane, γ - (methacryloyloxy) propyltrimethoxysilane, N- (2-aminoethyl) -3-aminopropyltrimethoxysilane and N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane.

14. The process of any one of claims 1 to 7, wherein the Silicalite series pure silica molecular sieves are one or more selected from the group consisting of Silicalite-1, MCM-41 and SBA-15.

15. The process according to claim 8, wherein molecular sieve catalyst B is caused to comprise the metallic element Z by either (i) or (ii),

(ii) and (B2) forming an aqueous dispersion by the copper-based catalyst A particles subjected to the second hydrothermal treatment in the step (B), the molecular sieve catalyst B and water, or directly adding the copper-based catalyst A particles obtained by the second hydrothermal treatment into the synthesis solution of the molecular sieve catalyst B to obtain an aqueous dispersion, dissolving part of metal ions of the catalyst A particles into a liquid phase by adjusting the pH value of the obtained aqueous dispersion, then carrying out hydrothermal treatment on the aqueous dispersion in a hydrothermal reaction kettle at the temperature of 100 ℃ and 300 ℃ for 1-96h, filtering, washing, drying and roasting to obtain the core/shell catalyst with one or more metals contained in the core doped in the shell layer.

16. The process as claimed in claim 15, wherein in (ii), the aqueous dispersion is hydrothermally treated in a hydrothermal reaction vessel at 150 ℃ and 250 ℃ for 24 to 72 h.

17. The process of any of claims 1 to 7 wherein the molecular sieve catalyst B is one or more selected from H-MOR, H-ZSM-5, H-ZSM-35 and H- β.

18. The process according to claim 17 wherein the molecular sieve catalyst B is H-MOR and/or H-ZSM-35.

19. The process according to any one of claims 1 to 7, wherein the total amount of catalyst A and catalyst B is greater than 80% based on the total weight of the core/shell catalyst.

20. The process according to claim 19, wherein the total amount of catalyst a and catalyst B is greater than 90% based on the total weight of the core/shell catalyst.

21. The process according to any one of claims 1 to 7, wherein the mass ratio of catalyst A to catalyst B is from 0.1 to 10.

22. The process according to claim 21, wherein the mass ratio of catalyst a to catalyst B is from 0.5 to 5.

23. The process according to claim 21, wherein the mass ratio of catalyst a to catalyst B is from 1 to 5.

24. The process according to any one of claims 1 to 7, wherein the copper-based catalyst A is prepared by:

(2) high-efficiency accurate precipitation method: preparing an aqueous solution A of a soluble Cu salt and optionally a soluble M salt, preparing a solution selected from NaOH, Na₂CO₃And NaHCO₃Adding the solution A and the solution B into a reactor by using a pulse liquid phase pump respectively, wherein the adding rate of the solution A and the solution B is required to ensure that the pH value of a mixture formed by the added solution A and the added solution B in real time is 8-14, the adding process is carried out under heating and stirring, the heating temperature is kept at 25-100 ℃, aging is carried out for 2-48h after the adding is finished, precipitates are filtered out, washing is carried out by deionized water, drying is carried out for 5-24h at 50-150 ℃, and roasting is carried out for 1-24h at 600 ℃ of 350-; and

25. A core/shell catalyst made by the process according to any one of claims 1-24.

26. Use of a core/shell catalyst prepared by a process according to any one of claims 1 to 24 as a catalyst in the direct preparation of ethanol from dimethyl ether and synthesis gas.