阅读说明：本技术 以介孔分子筛为载体的催化剂及其制备方法和应用 (Catalyst using mesoporous molecular sieve as carrier, preparation method and application thereof ) 是由 武洁花 赵清锐 邵芸 张明森 刘东兵 于 2020-06-16 设计创作，主要内容包括：本发明涉及催化领域,公开了以介孔分子筛为载体的催化剂及其制备方法和应用,该催化剂包括载体和负载于所述载体上的活性组分,其中,所述载体为介孔分子筛；所述活性组分包括La、Ba和Li；其中,La、Ba和Li的摩尔比为1：0.004-0.04：1-20；其中,所述载体的平均孔径为5-10nm。该催化剂具有较大的孔径,具有更多的负载活性组分的活性位,同时,较大的孔径更有利于反应物和产物扩散。(The invention relates to the field of catalysis, and discloses a catalyst taking a mesoporous molecular sieve as a carrier, a preparation method and application thereof, wherein the catalyst comprises the carrier and an active component loaded on the carrier, wherein the carrier is the mesoporous molecular sieve; the active components include La, Ba and Li; wherein the molar ratio of La, Ba and Li is 1: 0.004-0.04: 1 to 20; wherein the average pore diameter of the carrier is 5-10 nm. The catalyst has larger pore diameter, has more active sites for loading active components, and simultaneously, the larger pore diameter is more beneficial to the diffusion of reactants and products.)

1. The catalyst with the mesoporous molecular sieve as the carrier is characterized by comprising the carrier and an active component loaded on the carrier, wherein the carrier is the mesoporous molecular sieve; the active components include La, Ba and Li;

wherein the molar ratio of La, Ba and Li is 1: 0.004-0.04: 1 to 20;

wherein the average pore diameter of the carrier is 5-10 nm.

2. The catalyst according to claim 1, wherein the specific surface area of the carrier is 700-1000m²(ii)/g, preferably 750-²/g；

And/or the pore volume of the support is 0.5-2.5cm³In g, preferably 0.6 to 2cm³/g；

And/or the average pore diameter of the carrier is 8-10 nm;

and/or, the molar ratio of La, Ba and Li is 1: 0.005-0.007: 1.6-16.

3. The catalyst according to claim 1 or 2, wherein the support is present in an amount of from 64 to 96.89 wt. -%, preferably from 72 to 94.89 wt. -%, based on the total weight of the catalyst;

and/or, the La content is 3-15 wt%, preferably 5-12.5 wt%;

and/or, the content of Ba is 0.01-2 wt.%, preferably 0.4-0.4 wt.%;

and/or the content of Li is from 0.01 to 15% by weight, preferably from 0.5 to 10% by weight;

and/or the active component is present in the form of an oxidation state.

4. A method for preparing a catalyst using a mesoporous molecular sieve as a carrier is characterized by comprising the following steps:

(1) under an acidic condition, carrying out contact reaction on a template agent, a pore-expanding agent, water and a silicon source, and then sequentially carrying out solid-liquid separation and roasting to obtain a mesoporous molecular sieve;

(2) loading active components on the mesoporous molecular sieve, wherein the active components comprise La, Ba and Li; wherein the molar ratio of La, Ba and Li is 1: 0.004-0.04: 1-20.

5. The method of claim 4, wherein the pore-expanding agent is selected from polystyrene and/or mesitylene; preferably polystyrene nano-microspheres;

and/or the average diameter of the polystyrene nano-microsphere is less than 200 nm;

and/or the preparation method of the pore-expanding agent comprises the following steps: in the presence of a solvent, mixing styrene and an initiator to carry out polymerization reaction, and then carrying out solid-liquid separation to obtain the polystyrene nano-microsphere.

6. The method of claim 5, wherein the initiator is at least one of a persulfate, a sulfate, and a sulfite; preferably, the initiator is a persulfate;

and/or the persulfate is a water-soluble salt, preferably sodium persulfate and/or potassium persulfate;

and/or the initiator, the styrene and the solvent are used in such amounts that the molar ratio of the initiator, the styrene and the solvent is 1: 50-100: 3000-4000;

and/or the polymerization reaction is carried out under the condition of stirring, and the rotating speed of the stirring is 400-500 r/min;

and/or the temperature of the polymerization reaction is 70-80 ℃, and the time of the polymerization reaction is 18-24 h;

and/or adding an initiator into styrene in a mixing mode, wherein the adding rate of the initiator is 0.1-10g/min based on 1g of styrene, and standing the obtained mixed solution for 20-22h after the addition is finished.

7. The method according to claim 4, 5 or 6, wherein in step (1), the acidic condition is controlled to have a pH of 2-5 using an acidic substance; the acidic substance is at least one of hydrochloric acid, phosphoric acid, sulfuric acid and nitric acid, and hydrochloric acid is preferred;

and/or, the template agent is a nonionic surfactant; preferably having the formula EO_aPO_bEO_aThe polyoxyethylene-polyoxypropylene-polyoxyethylene triblock copolymer of (a); more preferably, wherein a has a value of 10 to 100, b has a value of 40 to 80; further preferred is EO₂₀PO₇₀EO₂₀And/or EO₁₇PO₅₅EO₁₇。

And/or the silicon source is sodium silicate and/or tetramethoxysilane, preferably tetramethoxysilane;

and/or, the molar ratio of La, Ba and Li is 1: 0.005-0.007: 1.6-16.

8. The method of claim 6, wherein, in step (1), the templating agent, the water, and the silicon source as Si are used in amounts such that the molar ratio of the templating agent, the water, and the silicon source as Si is 1: 30000-65000: 40-60 parts;

and/or the amount of the pore-expanding agent and the template agent is such that the mass ratio of the pore-expanding agent to the template agent is 3-5: 1;

and/or the XRD pattern of the mesoporous molecular sieve has characteristic peaks at 100 DEG +/-0.3 DEG, 110 DEG +/-0.3 DEG and 200 DEG +/-0.3 DEG of 2 theta.

9. The method of claim 4, 6 or 7, wherein in step (1), the contact reaction is carried out by: adding a silicon source into the template agent, wherein the adding rate of the silicon source is 0.1-10g/min, preferably 0.1-5g/min based on 1g of the template agent;

and/or, the contact reaction is carried out under the vacuum condition, and the vacuum degree is 80-100 mba; the temperature of the contact reaction is 40-50 ℃, and the time is 2-4 h;

and/or, in the step (1), the roasting temperature is 500-600 ℃; the roasting time is 0.5-10h, preferably 3-9 h.

10. The method of claim 4, wherein in step (2), the load is loaded by:

impregnating the mesoporous molecular sieve with impregnation liquid containing a lanthanum precursor, a barium precursor and a lithium precursor, and then sequentially drying and roasting to obtain the catalyst taking the mesoporous molecular sieve as a carrier;

preferably, in the impregnation liquid, the concentration of the lanthanum precursor is 0.01 to 0.5 wt% in terms of lanthanum element, the concentration of the barium precursor is 0.001 to 0.3 wt% in terms of barium element, and the concentration of the lithium precursor is 0.0001 to 0.1 wt% in terms of lithium element;

and/or the dosage of the impregnation liquid is 80-120g relative to each gram of the carrier.

11. The method according to claim 10, wherein, in step (2), the lanthanum precursor is a water-soluble lanthanum salt, preferably at least one selected from lanthanum nitrate, lanthanum chloride and lanthanum chlorate, more preferably lanthanum nitrate;

and/or the barium precursor is water-soluble barium salt, preferably selected from barium nitrate and/or barium chloride;

and/or the lithium precursor is a water-soluble lithium salt, preferably selected from lithium nitrate and/or lithium acetate, more preferably lithium nitrate.

12. The process according to claim 10 or 11, wherein in step (2), the time of the impregnation is from 1 to 6h, preferably from 1 to 3 h; the temperature is 30-80 ℃;

and/or the drying temperature is 100-110 ℃, and the drying time is 1-3 h;

and/or, in the step (2), the roasting temperature is 500-650 ℃; the roasting time is 4-5 h.

13. A catalyst supported on a mesoporous molecular sieve, characterized in that the catalyst supported on a mesoporous molecular sieve is prepared by the method according to any one of claims 4 to 12.

14. A method for producing a hydrocarbon containing more than two carbon atoms from methane, the method comprising: contacting methane with the mesoporous molecular sieve supported catalyst of any one of claims 1-3 and 13 in the presence of oxygen;

or preparing a mesoporous molecular sieve supported catalyst according to the process of any of claims 4 to 12 and then contacting methane with the resulting mesoporous molecular sieve supported catalyst in the presence of oxygen.

15. The method according to claim 14, wherein the molar ratio of the amounts of methane and oxygen is 2-8: 1, preferably 3-8: 1;

and/or, the contact temperature is 500-750 ℃; the contact time is 1-10 h; the pressure of the contact is 0.005-0.5MPa, and the space velocity of the methane is 10000-100000 mL/(g.h), preferably 20000-75000 mL/(g.h).

Technical Field

The invention relates to the field of catalysis, in particular to a catalyst taking a mesoporous molecular sieve as a carrier, and a preparation method and application thereof.

Background

Ethylene is the largest commodity chemical and chemical basic component in the world. Ethylene and other C2+ hydrocarbon products can also be produced from methane by the Oxidative Coupling (OCM) reaction of methane. The technology is reducing ethylene (C)₂H₄) The method has great potential in the aspects of cost, energy and environmental emission in production, and meanwhile, because the methane oxidative coupling reaction is a strong exothermic reaction and is carried out at high temperature and is limited by the reaction temperature and the technical difficulty of the reaction process, no industrial scale production is produced so far, so that the development of the methane oxidative coupling catalyst with excellent performance has practical significance.

In order to lower the reaction temperature of oxidative coupling catalysts for methane, researchers have made much work, for example, CN109922880A discloses an Oxidative Coupling of Methane (OCM) catalyst composition characterized by the general formula Sr_1.0Ce_aYb_bO_cWherein a is from about 0.01 to about 2.0, wherein b is from about 0.01 to about 2.0, wherein the sum (a + b) is not 1.0, andwherein c balances the oxidation state. CN109890501A discloses an Oxidative Coupling of Methane (OCM) catalyst composition comprising: (i) Sr-Ce-Yb-O perovskite; (ii) one or more metal oxides selected from the group consisting of strontium (Sr), cerium (Ce) and ytterbium (Yb); wherein the one or more oxides comprise: a single metal oxide, a mixture of single metal oxides, a mixed metal oxide, a mixture of mixed metal oxides, a mixture of single and mixed metal oxides, or a combination thereof. The prepared catalyst has the problems of high reaction temperature, complex catalyst preparation process and long preparation period, and brings difficulty to industrial scale-up production.

Disclosure of Invention

The invention aims to solve the problems of high reaction temperature, complex catalyst preparation process and poor reaction stability in the prior art, and provides a catalyst taking a mesoporous molecular sieve as a carrier, a preparation method and application thereof, wherein the catalyst has larger aperture and more active sites for loading active components, and meanwhile, the larger aperture is more beneficial to the diffusion of reactants and products; when the catalyst taking the mesoporous molecular sieve as a carrier is prepared, a template agent, a silicon source and a pore-expanding agent are added, and under an acidic condition, the preparation of the mesoporous molecular sieve with larger aperture is facilitated through the synergistic effect of the template agent, the silicon source and the pore-expanding agent, so that the catalyst has more active sites for loading active components; the catalyst can ensure that the reaction for preparing the hydrocarbon above carbon by methane is carried out at a lower temperature (such as within the range of 500-750 ℃), reduces the requirements on a reactor and operating conditions, has higher methane conversion rate and higher hydrocarbon selectivity above carbon, and is more beneficial to industrial scale-up production.

In order to achieve the above object, the present invention provides a catalyst using a mesoporous molecular sieve as a carrier, the catalyst comprising a carrier and an active component supported on the carrier, wherein the carrier is a mesoporous molecular sieve; the active components include La, Ba and Li;

wherein the molar ratio of La, Ba and Li is 1: 0.004-0.04: 1 to 20;

wherein the average pore diameter of the carrier is 5-10 nm.

The catalyst using the mesoporous molecular sieve as the carrier has larger aperture and more active sites for loading active components, and meanwhile, the larger aperture is more beneficial to the diffusion of reactants and products, thereby promoting the progress of methane oxidation coupling reaction.

In a second aspect of the present invention, there is provided a method for preparing a catalyst supported on a mesoporous molecular sieve, the method comprising:

(1) under an acidic condition, carrying out contact reaction on a template agent, a pore-expanding agent, water and a silicon source, and then sequentially carrying out solid-liquid separation and roasting to obtain a mesoporous molecular sieve;

(2) loading active components on the mesoporous molecular sieve, wherein the active components comprise La, Ba and Li; wherein the molar ratio of La, Ba and Li is 1: 0.004-0.04: 1-20.

In a third aspect of the present invention, a catalyst using a mesoporous molecular sieve as a carrier is provided, and the catalyst using a mesoporous molecular sieve as a carrier is prepared by the above method.

In a fourth aspect of the present invention, there is provided a process for producing a hydrocarbon above carbon dioxide from methane, the process comprising: in the presence of oxygen, methane is contacted with the catalyst taking the mesoporous molecular sieve as a carrier;

or preparing the catalyst taking the mesoporous molecular sieve as the carrier according to the method, and then contacting methane with the obtained catalyst taking the mesoporous molecular sieve as the carrier in the presence of oxygen.

The method for preparing the catalyst with the mesoporous molecular sieve as the carrier is characterized in that a pore-expanding agent is added into a reaction system in the process of preparing the mesoporous molecular sieve, and the mesoporous molecular sieve with larger aperture is more favorably prepared through the synergistic action of a template agent, a silicon source and the pore-expanding agent, so that the catalyst has more active sites for loading active components, and the progress of methane oxidation coupling reaction is promoted.

The method for preparing the hydrocarbon above carbon by methane is characterized in that the methane is contacted with the catalyst taking the mesoporous molecular sieve as the carrier in the presence of oxygen to prepare the hydrocarbon above carbon, the catalyst taking the mesoporous molecular sieve as the carrier can ensure that the reaction for preparing the hydrocarbon above carbon by methane can be carried out at lower temperature (such as 500-650 ℃), the requirements on a reactor and operating conditions are reduced, and the method has higher methane conversion rate and higher selectivity of the hydrocarbon above carbon, and is more beneficial to industrial amplification production.

Drawings

FIG. 1 is a TEM image of a transmission electron microscope of a mesoporous molecular sieve obtained according to example 1.

Detailed Description

The endpoints of the ranges and any values disclosed herein are not limited to the precise range or value, and such ranges or values should be understood to encompass values close to those ranges or values. For ranges of values, between the endpoints of each of the ranges and the individual points, and between the individual points may be combined with each other to give one or more new ranges of values, and these ranges of values should be considered as specifically disclosed herein.

The invention provides a catalyst taking a mesoporous molecular sieve as a carrier, which comprises a carrier and an active component loaded on the carrier, wherein the carrier is the mesoporous molecular sieve; the active components include La, Ba and Li;

wherein the molar ratio of La, Ba and Li is 1: 0.004-0.04: 1 to 20;

wherein the average pore diameter of the carrier is 5-10 nm.

In some embodiments of the present invention, preferably, the molar ratio of La, Ba and Li is 1: 0.005-0.007: 1.6-16.

In some embodiments of the present invention, the specific surface area, pore volume and pore diameter of the catalyst can be measured according to a nitrogen adsorption method, the specific surface area is calculated by using a BET method, and the pore volume is calculated by using a BJH model. The specific surface area of the carrier is preferably 700-1000m²(ii)/g, more preferably 750-²(ii) in terms of/g. The pore volume of the support is preferably from 0.5 to 2.5cm³In g, more preferably 0.6 to 2cm³(ii) in terms of/g. The average pore diameter of the support is preferably 8 to 10 nm.

In some embodiments of the present invention, in order to further secure the catalytic effect of the catalyst, the content of the support is preferably 64 to 96.89% by weight, more preferably 72 to 94.89% by weight, based on the total weight of the catalyst. The content of La is preferably 3 to 15% by weight, more preferably 5 to 12.5% by weight. The content of Ba is preferably 0.01 to 2% by weight, more preferably 0.4 to 0.4% by weight. The content of Li is preferably 0.01 to 15% by weight, more preferably 0.5 to 10% by weight.

In some embodiments of the invention, the active component is present in an oxidized form.

In a second aspect of the present invention, there is provided a method for preparing a catalyst supported on a mesoporous molecular sieve, the method comprising:

(1) under an acidic condition, carrying out contact reaction on a template agent, a pore-expanding agent, water and a silicon source, and then sequentially carrying out solid-liquid separation and roasting to obtain a mesoporous molecular sieve;

(2) loading active components on the mesoporous molecular sieve, wherein the active components comprise La, Ba and Li; wherein the molar ratio of La, Ba and Li is 1: 0.004-0.04: 1-20.

In some embodiments of the invention, the mesoporous molecular sieve has an XRD pattern with characteristic peaks at 100 ° ± 0.3 °, 110 ° ± 0.3 ° and 200 ° ± 0.3 ° 2 Θ.

In some embodiments of the present invention, the pore-expanding agent is a substance capable of enlarging the pore size of the mesoporous molecular sieve, and the pore-expanding agent is preferably selected from at least one of polystyrene and mesitylene; more preferably polystyrene nanospheres.

In some embodiments of the invention, the polystyrene nanospheres have an average diameter of less than 200 nm.

In some embodiments of the present invention, the polystyrene nanospheres may be prepared by themselves. According to a preferred embodiment of the present invention, the preparation method of the polystyrene nanosphere comprises: in the presence of a solvent, mixing styrene and an initiator to carry out polymerization reaction, and then carrying out solid-liquid separation to obtain the polystyrene nano-microsphere.

In some embodiments of the invention, preferably the solvent is water, more preferably nitrogen degassed water.

In some embodiments of the present invention, the preparation method of the polystyrene nanosphere may further comprise washing styrene with alkaline solution, and then washing with water (preferably deionized water) to remove the polymerization inhibitor in the styrene raw material.

In some embodiments of the present invention, preferably, the alkaline substance in the lye is at least one of sodium hydroxide, sodium bicarbonate, sodium carbonate and potassium hydroxide, preferably sodium hydroxide. Preferably, the molar concentration of the alkaline substance is 0.05-0.1 mol/L.

In some embodiments of the present invention, the method for preparing polystyrene may further comprise crushing and grinding polystyrene to obtain polystyrene powder.

In some embodiments of the invention, the initiator is preferably at least one of a persulfate, a sulfate, and a sulfite; more preferably, the initiator is a persulfate.

In some embodiments of the invention, the persulfate salt is a water-soluble salt, preferably sodium persulfate and/or potassium persulfate.

In some embodiments of the present invention, preferably, the initiator, the styrene, and the solvent are used in amounts such that the molar ratio of the initiator, the styrene, and the solvent is from 1:50 to 100: 3000-4000. In the process of preparing the pore-expanding agent, the solvent may be water.

In some embodiments of the present invention, to further make the structure of the pore-expanding agent highly ordered, it is preferable that the polymerization reaction is performed under stirring at a rotation speed of 400 and 500 rpm.

In some embodiments of the present invention, in order to separate the pore-enlarging agent from the solution as quickly as possible, it is preferable to perform centrifugation using a centrifuge at 6000-.

In some embodiments of the invention, the polymerization temperature is preferably 70-80 ℃ to further promote the formation of the pore-expanding agent. The polymerization time is preferably 18 to 24 hours.

In some embodiments of the present invention, to further promote the formation of the pore-expanding agent, the initiator is added to styrene at a rate of 0.1 to 10g/min based on 1g of styrene, and after completion of the addition, the resulting mixed solution is allowed to stand for 20 to 22 hours.

In some embodiments of the invention, in step (1), the acidic conditions are controlled to a pH of 2 to 5 using an acidic substance; the acidic substance is at least one of hydrochloric acid, phosphoric acid, sulfuric acid and nitric acid, and hydrochloric acid is preferred.

In some embodiments of the present invention, the template agent may be a nonionic surfactant, mainly performing a special structure synthesis, and performing a structure-directing function; preferably having the formula EO_aPO_bEO_aThe polyoxyethylene-polyoxypropylene-polyoxyethylene triblock copolymer of (a); more preferably, wherein a has a value of 10 to 100, b has a value of 40 to 80; further preferred is EO₂₀PO₇₀EO₂₀And/or EO₁₇PO₅₅EO₁₇(ii) a Specifically, the source of the template agent is not limited in the present invention and may be obtained commercially (e.g., from Sigma-Aldrich under the trade name P123, formula EO)₂₀PO₇₀EO₂₀) The compound can also be prepared by adopting a method in the prior art, and the details are not repeated here.

In some embodiments of the present invention, there is no particular limitation on the kind of the silicon source as long as it can provide silicon element, and preferably, the silicon source is sodium silicate and/or tetramethyloxysilane, more preferably tetraethyl silicate.

In some embodiments of the present invention, preferably, the molar ratio of La, Ba and Li is 1: 0.005-0.007: 1.6-16.

In some embodiments of the present invention, to further ensure the generation of the mesoporous molecular sieve, in step (1), the templating agent, the water, and the silicon source as Si are used in amounts such that the molar ratio of the templating agent, the water, and the silicon source as Si is 1: 30000-65000: 40-60 parts;

in some embodiments of the present invention, in order to further enlarge the pore size of the catalyst, in step (1), the pore-expanding agent and the templating agent are used in an amount such that the mass ratio of the pore-expanding agent to the templating agent is 3-5: 1.

In the invention, the adding sequence and the adding condition of the template agent, the silicon source, the water and the pore-expanding agent are not limited, preferably, the template agent, the silicon source and the water are firstly contacted at the stirring speed of 700-900 r/min, the mixture obtained after the contact and the pore-expanding agent are subjected to mixing reaction at the stirring speed of 90-150 r/min, and then the mesoporous molecular sieve is obtained by sequentially condensing and roasting.

In the invention, in order to accelerate the dissolution of the template agent, in the step (1), the contact system can be subjected to ultrasonic treatment, the ultrasonic treatment temperature can be 30-50 ℃, and the ultrasonic treatment time can be 3-5 h.

In some embodiments of the present invention, in order to further promote the generation of the mesoporous molecular sieve, in step (1), the contacting reaction is performed in a manner that: the silicon source is added into the template agent, and the adding speed of the silicon source is 0.1-10g/min, preferably 0.1-5g/min based on 1g of the template agent.

In some embodiments of the present invention, in order to shorten the reaction time, in step (1), the contact reaction is performed under vacuum, preferably at a vacuum degree of 80 to 100 mba; the temperature of the contact reaction is preferably 40-50 ℃, and the time is preferably 2-4 h.

In some embodiments of the present invention, in step (1), the temperature of the roasting is preferably 500-; the calcination time is preferably 0.5 to 10 hours, more preferably 3 to 9 hours.

In some embodiments of the present invention, in step (2), there is no limitation on the manner of loading, and conventional technical means in the prior art may be adopted, and preferably, the manner of loading is: impregnating the mesoporous molecular sieve with impregnation liquid containing a lanthanum precursor, a barium precursor and a lithium precursor, and then drying and roasting the impregnated mesoporous molecular sieve in sequence to obtain the catalyst taking the mesoporous molecular sieve as a carrier. Specifically, the metal component enters the pore of the mesoporous structure by means of the capillary pressure of the pore structure of the carrier, and the metal component is adsorbed on the surface of the mesoporous molecular sieve until the metal component reaches the adsorption equilibrium in the carrier. The impregnation may be co-impregnation or stepwise impregnation, preferably co-impregnation.

In some embodiments of the present invention, in the step (2), in the impregnation liquid, the concentration of the lanthanum precursor in terms of lanthanum element is preferably 0.01 to 0.5 wt%, the concentration of the barium precursor in terms of barium element is preferably 0.001 to 0.3 wt%, and the concentration of the lithium precursor in terms of lithium element is preferably 0.0001 to 0.1 wt%.

In some embodiments of the invention, in step (2), the impregnation solution is used in an amount of 80 to 120g per gram of support.

In some embodiments of the present invention, there is no particular limitation on the lanthanum precursor, and preferably, in step (2), the lanthanum precursor is a water-soluble lanthanum salt, more preferably at least one selected from lanthanum nitrate, lanthanum chloride, and lanthanum chlorate, and further preferably lanthanum nitrate.

In some embodiments of the present invention, there is no particular limitation on the barium precursor, and preferably, the barium precursor is a water-soluble barium salt, more preferably selected from barium nitrate and/or barium chloride;

in some embodiments of the present invention, there is no particular limitation on the lithium precursor, and preferably, the lithium precursor is a water-soluble lithium salt, more preferably selected from lithium nitrate and/or lithium acetate, and even more preferably lithium nitrate.

In some embodiments of the present invention, in order to contact the support with the precursor solution more sufficiently, in step (2), the time of the impregnation is preferably 1 to 6 hours, more preferably 1 to 3 hours. The temperature of the impregnation is preferably from 30 to 80 ℃.

In the present invention, in the step (2), the solvent removal process after completion of the impregnation may be a process which is conventional in the art, and for example, a rotary evaporator may be used to remove the solvent in the impregnation system.

In some embodiments of the present invention, in step (2), the drying may be performed by a method conventional in the art, preferably, the drying is performed in a drying device, and the drying conditions may include a drying temperature of preferably 100 ℃. The drying time is preferably 1 to 3 hours.

In some embodiments of the present invention, in step (2), the calcination temperature is preferably 500-650 ℃ to promote the formation of the catalyst. The roasting time is preferably 4-5 h.

In the present invention, the method may further comprise a step of subjecting the obtained mesoporous molecular sieve supported catalyst. The forming method is not limited, and conventional extrusion forming can be adopted, and the obtained formed catalyst taking the mesoporous molecular sieve as the carrier can be cylindrical, honeycomb or flaky. And crushing and screening the molded catalyst taking the mesoporous molecular sieve as the carrier, wherein the particle size of the obtained crushed catalyst taking the mesoporous molecular sieve as the carrier is 40-60 meshes.

In a third aspect of the present invention, a catalyst using a mesoporous molecular sieve as a carrier is provided, and the catalyst using the mesoporous molecular sieve as the carrier is prepared by the above method.

In a fourth aspect of the present invention, there is provided a process for producing a hydrocarbon above carbon dioxide from methane, the process comprising: in the presence of oxygen, methane is contacted with the catalyst taking the mesoporous molecular sieve as a carrier;

or preparing the catalyst taking the mesoporous molecular sieve as the carrier according to the method, and then contacting methane with the obtained catalyst taking the mesoporous molecular sieve as the carrier in the presence of oxygen.

In the present invention, the contacting may be performed in a continuous flow reactor, and the present invention has no limitation on the type of the continuous flow reactor, and may be a fixed bed reactor, a stacked bed reactor, a fluidized bed reactor, a moving bed reactor, or an ebullating bed reactor. In particular, the mesoporous molecular sieve supported catalyst may be arranged in layers in a continuous flow reactor (e.g., a fixed bed) or mixed with a reactant stream (e.g., an ebullating bed).

In some embodiments of the present invention, in order to promote the catalytic reaction, increase the conversion of methane and increase the selectivity of hydrocarbons above carbon two, the molar ratio of the amounts of methane and oxygen may be 2 to 8:1, preferably 3-8: 1.

In the present invention, the contacting conditions are not particularly limited and may be conventionally selected in the art, and preferably, the contacting temperature is 500-. The contact time can be 1-12 h; the pressure of the contact is 0.005-0.5MPa, and the space velocity of the methane is 10000-100000 mL/(g.h), preferably 20000-75000 mL/(g.h).

In the present invention, the hydrocarbon containing more than two carbon atoms is at least one selected from the group consisting of ethane, ethylene, propane and propylene.

In the present invention, the unit "mL/(g.h)" is the amount (mL) of the total gas of methane and oxygen used at a time of 1 hour, relative to 1g of the catalyst by mass.

In the present invention, the pressure means gauge pressure.

The present invention will be described in detail below by way of examples.

In the examples and comparative examples, the reagents used were all commercially available analytical reagents. The room temperature means 25 ℃. The drying box is produced by Shanghai-Hengchang scientific instruments Co., Ltd, and has the model of DHG-9030A. The muffle furnace is manufactured by CARBOLITE corporation, model CWF 1100. The polyoxyethylene-polyoxypropylene-polyoxyethylene triblock copolymer is available from Sigma-Aldrich under the trade name P123 and has the molecular formula of EO₂₀PO₇₀EO₂₀Molecular weight 5800. Tetraethyl silicate, analytically pure, was purchased from Shanghai Allantin Biotechnology Ltd. In the experiment process, the pH value is measured by a Metler pH meter S220, a styrene reagent is purchased from Shanghai Aladdin Biotechnology GmbH, potassium persulfate is purchased from Beijing chemical reagent GmbH of the national medicine group, an alumina molecular sieve is purchased from Henan Mingze environmental protection technology GmbH.

Preparation example 1

Washing 100mL of styrene with an equal volume of sodium hydroxide solution for six times, wherein the concentration of sodium hydroxide is 0.1mol/L, then washing with equal volume of distilled water for six times, adding a washed organic phase into 835mL of nitrogen degassed water at 80 ℃, then adding 50mL of potassium persulfate aqueous solution under the stirring of 500 revolutions per minute, wherein the concentration of potassium persulfate is 0.24mol/L, the adding speed of potassium persulfate is 0.5mL/min, standing the reaction mixture for 22h, centrifuging for 20min by using a centrifugal machine, wherein the rotating speed is 8000 revolutions per minute, recovering a solid product to obtain a pore-expanding agent, and SEM analysis shows that the average diameter of the obtained pore-expanding agent polystyrene nano microspheres is 100 nm.

Example 1

Adding 1g of template agent P123 into a solution (pH value is 4.2) consisting of 25mL of hydrochloric acid with the concentration of 2mol/L and 8g of deionized water, stirring to completely dissolve the P123, carrying out ultrasonic treatment at 40 ℃ for 2h, adding 2g of tetramethoxysilane (the adding rate of the tetramethoxysilane is 0.1g/min), stirring for 10min at the rotating speed of 850 r/min, adding 3g of the pore-expanding agent obtained in the preparation example 1, uniformly stirring the mixture at the rotating speed of 120 r/min, heating the mixture at 40 ℃ under the vacuum of 100mba for 3h, transferring the mixture to the air at room temperature for condensation, and roasting for 4h at 560 ℃ in a muffle furnace to obtain the mesoporous molecular sieve.

0.23g (0.0005mol) of lanthanum nitrate hexahydrate and 0.012g (4.6X 10 mol) of lanthanum nitrate were weighed out^-5mol) barium nitrate and 0.005g (7.2X 10)^-5mol) lithium nitrate is added into 100g deionized water, the mixture is uniformly stirred, 1g of the mesoporous molecular sieve prepared in preparation example 1 is added into the uniformly mixed solution, the solution is soaked for 6 hours at the temperature of 45 ℃, then a rotary evaporator is used for removing water in the system to obtain a solid product, the solid product is placed in a 110 ℃ oven, dried for 2 hours, then placed in a muffle furnace, the temperature is set to be 650 ℃, and the solid product is roasted for 5 hours to obtain the catalyst taking the mesoporous molecular sieve as a carrier.

Example 2

Adding 1g (0.00017mol) of template agent P123 into a solution (pH value is 3.5) consisting of 25mL of hydrochloric acid with the concentration of 2mol/L and 10g of deionized water, stirring to completely dissolve the P123, carrying out ultrasonic treatment at 40 ℃ for 2h, adding 1.67g of tetramethoxysilane (the adding rate of the tetramethoxysilane is 0.3g/min), stirring for 6min at the rotating speed of 800 r/min, adding 4g of the pore-expanding agent obtained in the preparation example 1, uniformly stirring the mixture at the rotating speed of 100 r/min, heating the mixture at 45 ℃ under the vacuum of 100mba for 2h, transferring the mixture into air at room temperature for condensation, and roasting at 500 ℃ for 6h in a muffle furnace to obtain the mesoporous molecular sieve.

0.32g (0.0007mol) of lanthanum nitrate hexahydrate and 0.02g (7.65X 10 mol) of lanthanum nitrate are weighed out^-5mol) barium nitrate and 0.04g (0.0006mol) lithium nitrate are added into 100g deionized water to be mixed and stirred uniformly, 1g of the mesoporous molecular sieve prepared in the preparation example 1 is added into the uniformly mixed solution to be soaked for 1.5h at the temperature of 50 ℃, then a rotary evaporator is used for removing water in the system to obtain a solid product, the solid product is placed in a 100 ℃ oven to be dried for 3h, then the solid product is placed in a muffle furnace at the set temperature of 550 ℃ to be roasted for 4h, and the catalyst taking the mesoporous molecular sieve as a carrier is obtained.

Example 3

Adding 1g (0.00017mol) of template agent P123 into a solution (pH value is 3.8) consisting of 25mL of hydrochloric acid with the concentration of 2mol/L and 12.5g of deionized water, stirring to completely dissolve the P123, carrying out ultrasonic treatment at 40 ℃ for 4 hours, adding 1.8g of tetramethoxysilane (the adding rate of the tetramethoxysilane is 0.2g/min), stirring for 5 minutes at the rotating speed of 750 r/min, adding 3.7g of the pore-expanding agent obtained in the preparation example 1, uniformly stirring the mixture at the rotating speed of 130 r/min, heating the mixture at 40 ℃ under the vacuum of 100mba for 4 hours, transferring the mixture to the air at room temperature for condensation, and roasting at 600 ℃ for 4 hours in a muffle furnace to obtain the mesoporous molecular sieve.

0.48g (0.0011mol) of lanthanum nitrate hexahydrate and 0.24g (9.2X 10 mol) of lanthanum nitrate are weighed^-4mol) barium nitrate and 0.01g (1.45X 10)^-4mol) lithium nitrate is added into 200g deionized water, the mixture is uniformly stirred, 2g of the mesoporous molecular sieve prepared in preparation example 1 is added into the uniformly mixed solution, the solution is soaked for 3 hours at the temperature of 80 ℃, then a rotary evaporator is used for removing solvent water in the system to obtain a solid product, the solid product is placed in a 110 ℃ oven, the drying is carried out for 2 hours, the solid product is placed in a muffle furnace, the temperature is set to be 650 ℃, and the calcination is carried out for 5 hours to obtain the catalyst taking the mesoporous molecular sieve as a carrier.

Comparative example 1

A catalyst supported on a mesoporous molecular sieve was prepared according to the method of example 1, except that the prepared mesoporous molecular sieve was replaced with an alumina molecular sieve.

Comparative example 2

A catalyst supported on a mesoporous molecular sieve was prepared as in example 1, except that no pore-enlarging agent was used.

Comparative example 3

A mesoporous molecular sieve supported catalyst was prepared as in example 1, except that lanthanum nitrate was replaced with cerium nitrate and barium nitrate was replaced with zinc nitrate.

Comparative example 4

A mesoporous molecular sieve supported catalyst was prepared as in example 2, except that lanthanum nitrate, barium nitrate, and lithium nitrate were used in amounts such that the molar ratio of La, Ba, and Li was 0.5:1: 1.5.

Test example 1

0.1g of the catalyst using the mesoporous molecular sieve obtained in the examples and the comparative examples as a carrier is loaded into a fixed bed reactor for methane oxidative coupling to prepare hydrocarbon above carbon dioxide, the reaction pressure is 0.008MPa, and the molar ratio of methane: the molar ratio of oxygen is 6:1, the contact temperature is 650 ℃, the reaction time is 5h, the space velocity of methane is 40000 mL/(g.h), and the reaction product is collected after the reaction.

Analysis of the reaction product composition was performed on a gas chromatograph available from Agilent under model 7890A. Wherein, hydrocarbons such as methane, ethane, ethylene, propane, propylene and the like are detected by an alumina column FID detector, methane, carbon monoxide, carbon dioxide and oxygen are detected by a carbon molecular sieve column TCD detector, and the calculation is carried out by a carbon balance method.

The methane conversion and the like are calculated as follows:

methane conversion ═ amount of methane consumed by the reaction/initial amount of methane × 100%

Ethylene selectivity is the amount of methane consumed by ethylene produced/total consumption of methane × 100%

Ethane selectivity is the amount of methane consumed by ethane produced/total consumption of methane × 100%

Propane selectivity is the amount of methane consumed by the propane formed/total consumption of methane x 100%

Propylene selectivity is the amount of methane consumed by propylene produced/total consumption of methane × 100%

Hydrocarbon selectivity over carbon two ═ ethane selectivity + ethylene selectivity + propylene selectivity + propane selectivity

The results obtained are shown in table 1.

Test example 2

The nitrogen adsorption and desorption experiments of the mesoporous molecular sieve samples obtained in the examples and the comparative examples were carried out on a full-automatic physicochemical adsorption analyzer model ASAP2020M + C, manufactured by Micromeritics, USA. The samples were degassed at 350 ℃ for 4 hours under vacuum prior to assay. The specific surface area of the sample was calculated by the BET method, and the pore volume and the average pore diameter were calculated by the BJH model, and the results are shown in table 1.

Test example 3

The elemental analysis method for the mesoporous molecular sieve supported catalysts in the examples and comparative examples was X-ray fluorescence spectroscopy (XRF) analysis with an XRF instrument model malvern panalyticepsilon1, and the results are shown in table 1, wherein the lanthanum content, barium content and lithium content are shown in table 1, with the balance being the support content, based on 100 wt%.

Test example 4

The mesoporous molecular sieve samples obtained in the examples were subjected to X-ray powder diffractometry tests using a copper target with a characteristic spectral wavelength on a Bruker D8 Adti diffractometer From the XRD pattern, the characteristic peaks of the mesoporous molecular sieve with 2 theta angles of 100 degrees, 110 degrees and 200 degrees indicate that the mesoporous molecular sieve has the basic characteristics of SBA-15. Similarly, the mesoporous molecular sieves obtained in examples 2 and 3 also show characteristic peaks at 2 theta angles of 100 degrees, 110 degrees and 200 degrees according to XRD detection.

Test example 5

The mesoporous molecular sieves obtained in examples and comparative examples were subjected to transmission electron microscopy and TEM imaging was performed using JEOL for 2100F FEG TEM with schottky field emission source. Acceleration voltage of 200kv, energy dispersive X-ray (EDX) analysis Using a low background double inclined support and an INCAX-Sight silicon (lithium) detector for EDX, 50mm area at 25 °²130 eV. The transmission electron micrograph of example 1 is shown in FIG. 1. As can be seen from fig. 1, the mesoporous molecular sieve has a typical 1D pore structure. Similarly, the mesoporous molecular sieves SBA-15 obtained in examples 2 and 3 have typical 1D channel structures as detected by a transmission electron microscope.

TABLE 1

As can be seen from Table 1, when the mesoporous molecular sieve supported catalysts obtained in examples 1-3 and comparative examples 1-4 are used in the oxidative coupling reaction of methane, examples 1-3 have a relatively high methane conversion rate and a hydrocarbon selectivity over carbon two, and after 5 hours of reaction, the relatively high methane conversion rate and the hydrocarbon selectivity over carbon two can still be maintained, and the hydrocarbon selectivity over carbon two, such as the methane conversion rate, the ethane selectivity, and the like of comparative examples 1-4 are all lower than those of examples 1-3, which shows that the mesoporous molecular sieve supported catalyst of the present invention has excellent catalytic performance when used in the oxidative coupling reaction of methane.

Comparing example 1 with other examples, it can be seen that a mesoporous molecular sieve supported catalyst having particularly excellent catalytic performance can be obtained by preparing in the following manner:

adding a template agent P123 into a solution (pH value is 4.2-4.5) consisting of hydrochloric acid and deionized water, stirring to completely dissolve the P123, carrying out ultrasonic treatment at 40-42 ℃ for 2-2.2h, adding tetramethoxysilane (the adding speed of the tetramethoxysilane is 0.1-0.12g/min), stirring at the rotating speed of 850-, the dosage of the hydrochloric acid is 25-25.5mL, the dosage of the deionized water is 8-8.2g, the dosage of the tetramethoxysilane is 2-2.2g, and the dosage of the pore-expanding agent is 2-2.2 g;

adding lanthanum nitrate hexahydrate, barium nitrate and lithium nitrate into deionized water, mixing and stirring uniformly, adding the mesoporous molecular sieve prepared in preparation example 1 into the uniformly mixed solution, soaking for 6-6.2h at the temperature of 45-46 ℃, removing water in the system by using a rotary evaporator to obtain a solid product, placing the solid product in a 110-112 ℃ oven, drying for 2-2.1h, then placing the dried product in a muffle furnace, setting the temperature to be 650-652 ℃, and roasting for 5-5.2h to obtain the catalyst taking the mesoporous molecular sieve as a carrier, wherein the dosage of barium nitrate is 0.012-0.013g, the dosage of lithium nitrate is 0.005-0.0053g, the dosage of deionized water is 100-110g, and the dosage of the mesoporous molecular sieve is 1-1.2g relative to 0.23g of lanthanum nitrate hexahydrate.

The preferred embodiments of the present invention have been described above in detail, but the present invention is not limited thereto. Within the scope of the technical idea of the invention, many simple modifications can be made to the technical solution of the invention, including combinations of various technical features in any other suitable way, and these simple modifications and combinations should also be regarded as the disclosure of the invention, and all fall within the scope of the invention.