Catalyst and preparation method therefor and use therefor

Abstract

The present application discloses a catalyst and preparation method therefor and use therefor. The catalyst comprises: an alumina support and an active component, wherein the alumina support comprises alumina, a IA main group element component and silicon element, based on the total weight of the support, a content of the IA main group element component is in a range from 510 ppm to 25,300 ppm, and a content of silicon element is in a range from 10ppm to 300ppm; and a ratio of an acid amount at low temperature to an acid amount at high temperature of the support is 1 or more. The present application improves the stability of the support, enhances the selectivity and activity of the catalyst, and extends the lifespan of the catalyst by limiting the content of the IA main group element component, the content of the silicon element, and the acid amount at low temperature and acid amount at high temperature in the support.

Description

[0001] Specification

[0002] CATALYST AND PREPARATION METHOD THEREFOR AND USE

[0003] THEREFOR

[0004] FIELD OF THE INVENTION

[0005] The present application relates to the technical field catalytic material, specifically to a catalyst and preparation method therefor and use therefor.

[0006] BACKGROUND OF THE INVENTION

[0007] Dimethyl carbonate (DMC) contains active functional groups such as methyl, carbonyl, and methoxyl groups in its molecular formula, and is easy to conduct chemical reactions with various organic compounds such as alcohols, amines, hydrazines, and esters. As a green chemical intermediate, it has received widespread attention in the fields of construction, automobiles, medical equipment, lithium batteries, and the like in the past two decades.

[0008] The industrial production routes of dimethyl carbonate comprise phosgene method, transesterification method, liquid-phase methanol oxidative carbonylation method, gas-phase methanol oxidative carbonylation method, and indirect gas-phase oxidative carbonylation method. The existing synthesis methods of DMC mainly comprise transesterification method, liquid-phase oxidative carbonylation method, urea method, dimethyl oxalate decarbonylation method, carbon dioxide direct synthesis method, and methanol gas-phase oxidative carbonylation method. Among them, the methanol gas-phase oxidative carbonylation method is currently the more widely used synthesis method, and its synthesis route is divided into two steps. The first step is the reaction to synthesize methyl nitrite, and the second step is the carbonylation reaction between carbon monoxide and methyl nitrite to synthesize DMC. This process has the advantages of mild reaction conditions, environmental friendliness and no pollution, easy separation of catalysts, and the like, which is increasingly attracting people's attention. However, the stability of the catalyst used in this method is poor, and after a period of use, deactivation phenomenon occurs, leading to a decrease in catalytic activity and selectivity, and a short lifespan of the catalyst. How to make catalysts have high activity, high selectivity, and long lifespan is a key technical challenge in the art.

[0009] SUMMARY

[0010] The present application provides a catalyst and preparation method therefor and use therefor to solve the problems of poor stability of catalysts, deactivation phenomenon after use for a period of time, decreased catalytic activity and selectivity, and short lifespan of catalysts in the prior art.

[0011] In a first aspect, the present application provides a catalyst, comprising an alumina support and an active component, wherein the alumina support comprises alumina, a lAmain group element component and silicon element, based on the total weight of the alumina support, a total content of the IA main group element component is in a range from 510 ppm to 25,300 ppm, and a content of silicon element is in a range from lOppm to 300ppm; and a ratio of an acid amount at low temperature to an acid amount at high temperature of the alumina support is 1 or more.

[0012] In some optional embodiments, based on the total weight of the alumina support, a content of the lA main group element component is in a range from 3000ppm to 25,300ppm, and a content of silicon element is in a range from lOOppm to 200ppm; and a ratio of an acid amount at low temperature to an acid amount at high temperature of the alumina support is in a range from 1 to 15.

[0013] In some optional embodiments, the IA main group element component comprises sodium element and other IA main group elements, wherein, a content of sodium element is in a range from lOppm to 300ppm.

[0014] In some optional embodiments, the acid amount is determined by the ammonia gas-Temperature Programmed Desorption (NH3-TPD) method, the acid amount at low temperature refers to the acid amount with peak positions between 100°C and 310°C, and the acid amount at high temperature refers to the acid amount with peak positions between 310°C and 550°C.

[0015] In some optional embodiments, the active component comprises a platinum group metal component and an auxiliary active component; optionally, based on the total weight of the catalyst, a loading amount of the platinum group metal component is in a range from 0.1 wt% to 2wt%, further, optionally, in a range from 0.5wt% to 2wt%; and optionally, based on the total weight of the catalyst, a loading amount of the auxiliary active component is in a range from 0.1 wt% to 2wt%, and further, optionally, in a range from 0.5wt% to 2wt%.

[0016] In some optional embodiments, the platinum group metal component comprises Pd; and / or, the auxiliary active component comprise at least one of Cu, Co and Ni.

[0017] In a second aspect, the present application also provides a method for preparing the catalyst above, wherein the method comprises the following steps:

[0018] 51, using an aluminum oxide matrix or an alumina hydrate for ion exchange pretreatment, drying, calcining, impregnating in an aqueous solution containing other IA main group elements for ion exchange treatment, drying and calcining to obtain an alumina support; and

[0019] 52, using an impregnation solution containing the platinum group metal component and the auxiliary active component to impregnate the alumina support obtained in SI, drying and calcining to obtain the catalyst.

[0020] In some optional embodiments, the ion exchange pretreatment comprises using an ammonium salt aqueous solution for ion exchange; and optionally, a weight concentration of the ammonium salt aqueous solution is in a range from lwt% to 3wt%, and the ion exchange pretreatment is carried out at a temperature ranging from 40 °C to 80 °C for a time period ranging from 1 hour to 24 hours. In some optional embodiments, in S2, a process for preparing the impregnation solution comprises: mixing the platinum group metal components, the auxiliary active components, and a first solution, adding water or a second solution to obtain the impregnation solution; wherein, a concentration of the first solution is higher than a concentration of the second solution; optionally, the concentration of the first solution is in a range from 5wt% to 20wt%; further optionally, the first solution comprises at least one of ammonia water, hydrochloric acid aqueous solution, sodium chloride aqueous solution and ammonium chloride aqueous solution; optionally, the second solution comprises at least one of ammonia water, hydrochloric acid aqueous solution, sodium chloride aqueous solution, and ammonium chloride aqueous solution; and / or, a weight ratio of the impregnation solution to the alumina support is in a range from 0.5: 1 to 3: l.

[0021] In some optional embodiments, in SI, the calcining is carried out at a temperature ranging from 200°C to 300°C for a time period ranging from 3 hours to 5 hours; and / or, the calcining in S2 is carried out at a temperature ranging from 120°C to 200°C for a time period ranging from 2 hours to 24 hours.

[0022] In a third aspect, the present invention also provides a use of the above catalyst or the catalyst prepared by the above method in the production of dimethyl carbonate through gas-phase carbonylation reaction.

[0023] The technical solution of this application has the following advantages.

[0024] The catalyst provided in the present application comprises an alumina support and an active component, wherein the alumina support comprises alumina, a IA main group element component and silicon element, based on the total weight of the alumina support, a content of the IA main group element component is in a range from 510 ppm to 25,300 ppm, and a content of silicon element is in a range from lOppm to 300ppm; and a ratio of an acid amount at low temperature to an acid amount at high temperature of the alumina support is 1 or more. The present application improves the stability of the alumina support, enhances the selectivity and activity of the catalyst, and extends the lifespan of the catalyst by limiting the content of the IA main group element component, the content of the silicon element, and the acid amount at low temperature and acid amount at high temperature of the alumina support. Specifically, on the one hand, according to the principle of the lowest system energy, a specific content of silicon interacts with the strong active centers on the surface of the alumina support, weakening the strong active centers on the surface of the alumina support, avoiding the aggregation of active components caused by the strong interaction between the active components at the strong active centers and the alumina support, and improving the dispersion degree of precious metal active components; on the other hand, the presence of silicon at high temperatures causes alumina to form a complex on the surface of the material, preventing the dehydration and condensation of adjacent aluminum atom and hydroxyl groups, thereby preventing the sintering of aluminum atoms and improving the thermal stability of the alumina support; on the other hand, the specific content of the IA main group element component can partially migrate to the cluster of auxiliary active components to form the lowest azeotrope, thereby inhibiting the loss of active components. In addition, the alkalinity of the IA main group element component in the alumina support can weaken the acidity of the strong acidic center on the surface of the alumina support to a certain extent. Using support materials with suitable acidic distribution, acid active centers at low temperature are conducive to the activation of raw materials, and fewer strong acid active centers at high temperature prevent side reactions such as raw material decomposition and the aggregation and growth of surface active components, thereby improving the selectivity and activity of the catalyst.

[0025] The catalyst provided in the present application further improves the stability of the alumina support as well as the selectivity and activity of the catalyst, and extends the lifespan of the catalyst by limiting the content of the IA main group element component, the content of silicon element, and the ratio of an acid amount at low temperature to an acid amount at high temperature of the alumina support.

[0026] In the catalyst provided in the present application, the IA main group element component comprise sodium element and other IA main group elements, with a sodium element content ranging from lOppm to 300ppm. By limiting in this way, due to the regulation to the physicochemical properties of the alumina support, the interaction between the active component and auxiliary active component with the alumina support is improved, which can further enhance the activity and stability of the catalyst.

[0027] The method for preparing the catalyst provided in the present application can regulate the content of the IA main group element component, the content of the silicon element, and the ratio of acid amount at low temperature to acid amount at high temperature of the alumina support through ion exchange pretreatment. Then, the loading of the active component can be achieved through the impregnation step. The preparation step is simple, the operation is convenient, and the application is easy to popularize.

[0028] The method for preparing the catalyst is provided in the present application, wherein a process for preparing the impregnation solution comprises: mixing platinum group metal component, auxiliary active component, and a first solution, adding water or a second solution to obtain the impregnation solution, wherein the concentration of the first solution is higher than that of the second solution. In the present application, by limiting the preparation steps of the impregnation solution, the first solution has good solubility for the platinum group metal component and auxiliary active component, which is conducive to the dissolution of the metal active components at low temperatures. The addition of water or the second solution can further adjust the concentration and pH of the impregnation solution, and is more conducive to the dispersion of the active components and auxiliary active components on the alumina support during the impregnation process.

[0029] The present application provided the use of the catalyst in the production of dimethyl carbonate through gas-phase carbonylation reaction, due to the specific composition of the catalyst, the catalyst has high activity, high selectivity, and long lifespan. The initial space-time yield is SlOg / L’h'1or more, with a maximum of 730g / L-h-1, and the selectivity is 94.6% or more. After running for 500 hours, the space-time yield is 457g / L’h-1, with a maximum of 750g / L’tr1and the selectivity is 94.3% or more. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0030] The following will provide a clear and complete description of the technical solution in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, not all of them. Based on the embodiments in the present application, all other embodiments obtained by ordinary technical personnel in this field without paying creative labor fall within the scope of protection of the present application.

[0031] Unless otherwise defined, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the technical field of the present application. The terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the present application. The terms "including" and "having" and any variations thereof in the Description and Claims of the present application, are intended to cover non-exclusive inclusion.

[0032] In the description of the embodiments of the present application, technical terms such as "first", "second", and the like are only used to distinguish different objects and cannot be understood as indicating or implying relative importance or implying the quantity, specific order, or primary and secondary relationships of the indicated technical features.

[0033] Referring to "embodiments" herein means that specific features, structures, or characteristics described in conjunction with the embodiments may be included in at least one embodiment of the present application. This phrase appearing in various positions in the Description does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. Technicians in this field explicitly and implicitly understand that the embodiments described herein can be combined with other embodiments.

[0034] The “range” disclosed in the present application is defined in the form of a lower limit and an upper limit. The given range is limited by selecting a lower limit and an upper limit, and the selected lower limit and upper limit define the boundary of a special range. The range defined by this mode can include or exclude end values, and can be combined arbitrarily, that is, any lower limit can be combined with any upper limit to form a range. For example, if a range of 60-120 and 80-110 is listed for specific parameters, it is also expected to be understood as a range of 60-110 and 80-120. In addition, if the minimum range values 1 and 2 are listed, and if the maximum range values 3, 4, and 5 are listed, the following ranges can all be expected: 1-3, 1-4, 1-5, 2-3, 2-4, and 2-5. In the present application, unless otherwise specified, the numerical range "a-b" represents an abbreviated representation of any combination of real numbers between a and b, where a and b are both real numbers. For example, the numerical range "0-5" indicates that all real numbers between "0-5" have been listed herein, and "0-5" is just an abbreviated representation of these numerical combinations. In addition, when a certain parameter is expressed as an integer greater or equal to 2, it is equivalent to disclosing that the parameter is, for example, integers 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0035] In the description of the embodiments of the present application, the term "and / or" is only a description of the association relationship of the associated objects, indicating that there can be three types of relationships, for example, A and / or B can indicate the presence of A alone, the presence of A and B simultaneously, and the presence of B alone. In addition, the character " / " herein generally indicates that the associated objects before and after this character have an "or" relationship.

[0036] In the description of the present embodiment, the term "at least one" refers to one or more (including one).

[0037] Some catalysts for preparing dimethyl carbonate have been disclosed in the prior art. For example, the catalysts disclosed in the prior art use activated carbon as a support, with palladium chloride as the main active component and copper chloride as the auxiliary active component. The optimal space time yield of DMC can reach 725g / (L’h), but it can only remain stable for about 8 hours. Although using 50ppm to lOOOppm methyl-chloroformate as a chlorine supplement agent can greatly extend the lifespan of the catalyst, the catalyst activity still decreases by 20% to 30% within 100 hours, and the lifespan of the catalyst needs to be improved.

[0038] There is also a catalyst with palladium chloride as the active center disclosed by prior art. Although the catalyst has good DMC selectivity, its stability is poor, and the catalyst will be deactivated after a period of reaction, and the catalytic activity and selectivity are seriously decreased.

[0039] Another catalyst disclosed by prior art uses a substance with a wide range of microporous structure, composed of manganese dioxide, pseudo-boehmite and activated carbon, as the support to obtain relatively high activity and selectivity, but the activity and selectivity of the catalyst are reduced after 500h of operation.

[0040] In summary, some reported catalysts for the preparation of dimethyl carbonate by gas phase oxidative carbonylation of CO and methyl nitrite have a common shortcoming, that is, the activity stability of the catalyst is poor and the lifespan of the catalyst is short. How to make the catalyst with high activity, high selectivity and long life is the key technical problem in the art.

[0041] In order to solve the above-mentioned problems existing in the related technologies, according to the first aspect of the present application, a catalyst is provided, wherein the catalyst comprises: an alumina support and an active component, wherein the alumina support comprises alumina, a lA main group element component and silicon element, based on the total weight of the alumina support, a content of the IA main group element component is in a range from 510 ppm to 25,300 ppm, and a content of silicon element is in a range from lOppm to 300ppm; a ratio of an acid amount at low temperature to an acid amount at high temperature of the alumina support is 1 or more.

[0042] Those skilled in the art can understand that silicon in the alumina support is a common major impurity in bauxite, which reacts with alkaline solutions to form hydrated sodium aluminosilicate and precipitates. In production, hydrated sodium aluminosilicate is referred to as sodium-silicon slag, and the IA main group element component such as sodium is introduced during the preparation process of alumina support (from raw materials for preparing alumina support such as sodium metaaluminate, sodium hydroxide, sodium carbonate, etc.). The sodium element in alumina mainly exists in three forms: adherent alkali, crystalline alkali, and intergranular alkali. Among the alkalis contained in aluminum hydroxide, adherent alkali can be removed by washing aluminum hydroxide with deionized water thoroughly, but crystalline alkali and intergranular alkali cannot be removed. The vast majority of crystalline alkali exists on the surface of alumina and only has a certain impact on the surface properties of alumina. However, in the intergranular alkali, sodium is doped into the alumina lattice, which will have a significant impact on the various physical and chemical properties of the alumina support. However, intergranular alkali is difficult to remove.

[0043] In some embodiments, based on the total weight of the alumina support, the content of the lA main group element component may be 510ppm, 540ppm, 600ppm, 630ppm, 680ppm, 710ppm, 760ppm, 780ppm, 810ppm, 900ppm, 1500ppm, 5000ppm, lOOOOppm, 15000ppm, 20000ppm, 25000ppm, 25300ppm, or within a range composed of the above any values; the content of silicon element is lOppm, 20ppm, 40ppm, 80ppm, lOOppm, 120ppm, 150ppm, 200ppm, 230ppm, 250ppm, 280ppm, 300ppm, or within a range composed of the above any values.

[0044] In some embodiments, the ratio of the acid amount at low temperature to the acid amount at high temperature of the alumina support is 1.5, 2, 2.5, 3, 3.5, 4, 4.8, 5.3, 8, 10, 15, or within a range composed of the above any values.

[0045] The present application improves the stability of the support, enhances the selectivity and activity of the catalyst, and extends the lifespan of the catalyst by limiting the content of the IA main group element component, the content of the silicon element, and the ratio of acid amount at low temperature to acid amount at high temperature of the alumina support. Specifically, on the one hand, according to the principle of the lowest system energy, an appropriate amount of silicon interacts with the strong active centers on the surface of the alumina support, weakening the activities of the strong active centers on the surface of the alumina support, avoiding the aggregation of active components caused by the strong interaction between the active components at the strong active centers and the alumina support, and improving the dispersion degree of precious metal active components; on the other hand, the presence of silicon at high temperatures causes alumina to form a complex on the surface of the material, preventing the dehydration and condensation of adjacent aluminum atom and hydroxyl groups, thereby preventing the sintering of aluminum atoms and improving the thermal stability of the alumina support. The specific amount of the IA main group element component can, on the one hand, partially migrate to the cluster of auxiliary active components to form the lowest azeotrope, thereby inhibiting the loss of active components, on the other hand, the alkalinity of the IA main group element component in the alumina support can weaken the acidity of the strong acidic center on the surface of the alumina support to a certain extent; using support materials with suitable acidic distribution, acid centers at low temperature are conducive to the activation of raw materials, and fewer acid centers at high temperature prevent side reactions such as raw material decomposition as well as the aggregation and growth of surface active components, thereby improving the selectivity and activity of the catalyst. If the content of the IA main group element component is too high, the IA main group element component has a relatively strong alkalinity, which destroys the excessive acid centers on the surface of the catalyst support, and the acid centers at low temperature are less, resulting in lower reaction activity; and if the content of the IA main group element component is too low and there are many strong acid centers on the surface of the support, the raw material methyl nitrite will undergo side reactions such as decomposition, and the surface active components will aggregate and grow, resulting in a decrease in the selectivity and activity of the catalyst. If the content of Si element is too high, due to the lower enthalpy of formation (AfH°M-o) of silicon oxide relative to metal oxides (alumina), the active center species exist in a low valence state, which is not conducive to the redox cycle of active center species, and there will be problems that catalysts will have poor stability and activity. If the content of Si element is too low, it cannot play the role of preventing the sintering of aluminum atoms, and the dehydration and condensation of adjacent aluminum atom and hydroxyl groups will result in poor thermal stability of the alumina support. If the ratio of the acid amount at low temperature to the acid amount at high temperature of the alumina support is less than 1, because the acid centers at low temperature are fewer than strong acid centers at high temperature in the effective active centers, there will be problems that side reactions such as the decomposition of raw material methyl nitrite will occur as well as the surface active components aggregate and grow, resulting in relatively low selectivity and activity of the catalyst. In some optional embodiments, based on the total weight of the alumina support, a total content of the IA main group element component is in a range from 1,000 ppm to 25,300 ppm, and a content of silicon element is in a range from 100 ppm to 200 ppm; and a ratio of an acid amount at low temperature to an acid amount at high temperature of the alumina support is in a range from 1 to 15.

[0046] The present application further improves the stability of the alumina support as well as the selectivity and activity of the catalyst, and extends the lifespan of the catalyst by limiting the content of the IA main group element component, the content of silicon element, and the ratio of an acid amount at low temperature to an acid amount at high temperature of the alumina support.

[0047] In some optional embodiments, the IA main group element component include sodium elements and other IA main group elements, wherein the content of sodium element is in a range from lOppm to 300ppm. In some optional embodiments, the content of sodium element is lOppm, 50ppm, 80ppm, 120ppm, 160ppm, 190ppm, 200ppm, 220ppm, 250ppm, 270ppm, 300ppm, or within a range composed of the above any values.

[0048] The present application limits the content of sodium element in the alumina support, due to the regulation of the physicochemical properties of the alumina support, the interaction between the active component and auxiliary active component with the component support is improved, which can further enhance the activity and stability of the catalyst. Since excessive sodium content will have a strong interaction with the surface active center of the catalyst, excessive sodium content is unfavorable to the reaction of generating dimethyl carbonate.

[0049] In some optional embodiments, the acid amount is determined by the ammonia gas-Temperature Programmed Desorption (NHa-TPD) method, wherein the acid amount at low temperature refers to the acid amount with peak positions between 100°C and 310°C, and the acid amount at high temperature refers to the acid amount with peak positions between 310°C and 550°C.

[0050] The testing principle of acid amount is as follows.

[0051] When alkaline gas molecules come into contact with solid catalysts (supports), in addition to gas-solid physical adsorption, chemical adsorption also occurs. The adsorption process starts from the strong acid site of the catalyst and gradually develops towards the weak acid site, while desorption is exactly the opposite. The temperature at which alkaline gas molecules on the weak acid site desorb is lower than the temperature at which alkaline gas molecules on the strong acid site desorb. Therefore, for a given catalyst, a suitable alkaline gas can be selected, and various experimental techniques for measuring gas adsorption and desorption can be used to measure the strength and acidity of the catalyst. The most commonly used method is the Temperature Programmed Desorption method.

[0052] Temperature Programmed Desorption (TPD) is a process in which a catalyst that has pre-adsorbed certain gas molecules is subjected to programmed heating and temperature rising, by using a stable flow rate of gas (usually using inert gas, such as He gas), the molecules adsorbed on the catalyst surface are desorbed at a certain temperature; as the temperature increases, the desorption rate increases; after several desorption peaks, the desorption is completed. By measuring the amount of alkaline gas desorbed, the total acid amount of the catalyst can be obtained. By calculating the area of various desorption peaks, the acid amounts of various acid sites can be obtained.

[0053] In some optional embodiments, the active component comprises a platinum group metal component and an auxiliary active component.

[0054] Optionally, based on the total weight of the catalyst, a loading amount of the platinum group metal component is in a range from 0.1 wt% to 2wt%; for example, the loading amount of platinum group metal component can be 0.1wt%, 0.5wt%, 0.8wt%, 1.0wt%, 1.2wt%, 1.5wt%, 1.7wt%, 2wt%, or within a range composed of the above any values; further optionally, based on the total weight of the catalyst, a loading amount of the platinum group metal component is in a range from 0.5wt% to 2wt%.

[0055] Optionally, based on the total weight of the catalyst, a loading amount of the auxiliary active component is in a range from 0.1 wt% to 2wt%; for example, the load of the auxiliary active component element may be 0.1wt%, 0.6wt%, 0.9wt%, l. lwt%, 1.4wt%, 1.8wt%, 2wt%, or within a range composed of the above any values. Further optionally, based on the total weight of the catalyst, a loading amount of the auxiliary active component is in a range from 0.5wt% to 2wt%.

[0056] In some optional embodiments, the platinum group metal component comprises Pd; and / or, the auxiliary active component comprise at least one of K, Cu, Co and Ni; and / or, the lA main group element component comprise one of Na, K, Li, Ru and Cs.

[0057] In some optional embodiments, the IA main group element component comprises one or a mixture of more of Na, K, Li, Ru and Cs. Further, optionally, the IA main group element component is a mixture of Na and K, a mixture of Na and Li, or a mixture of Na, K and Li.

[0058] In a second aspect, the present application also provides a method for preparing the catalyst, comprising the following steps:

[0059] 51, using an alumina oxide matrix or an alumina hydrate for ion exchange pretreatment, drying and calcining to obtain an alumina support;

[0060] 52, using an impregnation solution containing the platinum group metal component and the auxiliary active component to impregnate the alumina support obtained in SI, drying and calcining to obtain the catalyst.

[0061] The present application can regulate the content of the IA main group element component, the content of silicon element, and the ratio of acid amount at low temperature to acid amount at high temperature of the alumina support through ion exchange pretreatment. Then, the loading of the active component can be achieved through the impregnation step. The preparation step is simple, the operation is convenient, and the application is easy to popularize.

[0062] Specifically, the method for preparing the catalyst may comprise the following steps.

[0063] 1) alumina matrix or alumina hydrate Al is used for ion exchange pretreatment, and after drying and calcination, an alumina support with a content of IA main group element component ranging from 510ppm to 25,300ppm, a content of silicon element ranging from lOppm to 300ppm, and a ratio of an acid amount at low temperature to an acid amount at high temperature of the alumina support of 1 or more is obtained.

[0064] 2) a platinum group metal component, an auxiliary active component, and a first solution are mixed to prepare an impregnation solution Bl; the impregnation solution Bl is mixed with water or a second solution to obtain an impregnation solution B2; wherein, the concentration of the first solution is higher than that of the second solution. In the present application, by limiting the preparation steps of the impregnation solution, the first solution has good solubility for the platinum group metal component and the auxiliary active component, which is conducive to the dissolution of the metal active components at low temperatures. The addition of water or second solution can further adjust the concentration and pH of the impregnation solution, and is more conducive to the dispersion of the active component and auxiliary active component on the alumina support during the impregnation process.

[0065] 3) The alumina support is immersed in the impregnation solution B2 for a period of time.

[0066] 4) When the balance of impregnation is reached, the material therein is dried and calcined to obtain the catalyst product C.

[0067] In some optional embodiments, a process for ion exchange pretreatment described in step 1) comprises: firstly, an ammonium salt aqueous solution with a concentration of lwt%~3wt% is prepared, and then the commercially available alumina support is dispersed into the above-mentioned ammonium salt aqueous solution, filtered after reflux at a temperature ranging from 40°C to 80°C for a certain time, washed with deionized water for 1 to 5 times, dried overnight in an oven at 80°C to 110°C, and then calcined at a temperature ranging from 200°C to 300°C for 3 hours to 5 hours to obtain the required alumina support.

[0068] In some optional embodiments, the concentration of ammonium salt aqueous solution can be lwt%, 1.3wt%, 1.5wt%, 1.8wt%, 2.0wt%, 2.2wt%, 2.5wt%, 2.8wt%, 3.0wt%, or within a range composed of the above any values. The calcination temperature can be 200°C, 220°C, 250°C, 260°C, 280°C, 300°C, or within a range composed of the above any values. The calcination time can be 1 hour, 1.5 hours, 2 hours, 2.5 hours, 3 hours, or within a range composed of the above any values.

[0069] In some optional embodiments, the ammonium salt comprises at least one of ammonium nitrate, ammonium chloride, ammonium carbonate and ammonium bicarbonate.

[0070] In some optional embodiments, the ion exchange pretreatment step described in 1) further comprises an impregnation process for a second IA main group element (the IA main group element component other than sodium), i.e., preparing a salt solution containing a IA main group element other than sodium with a concentration of 2wt% to 10wt%, then dispersing the calcined support into the salt solution above, immersing it at room temperature for a certain time, drying overnight in an oven at 80°C to 110°C, and then calcining at 200°C to 300°C for 3 hours to 5 hours to obtain an alumina support.

[0071] In some optional embodiments, the second IA main group element component comprise one or a mixture of more of K, Li, Ru and Cs. Optionally, the salt solution containing the IA main group element component is selected from an aqueous solution of chloride salts, nitrate salts, and acetate salts.

[0072] In some optional embodiments, the platinum group metal component of 2) comprises at least Pd.

[0073] In some optional embodiments, the first solution of 2) is selected from at least one of ammonia water, hydrochloric acid aqueous solution, sodium chloride aqueous solution, and ammonium chloride aqueous solution. Optionally, the first solution is at least one of ammonia water, hydrochloric acid aqueous solution, and ammonium chloride aqueous solution. Furthermore optionally, the concentration of the first solution is in a range from 5wt% to 20wt%. For example, the concentration of the first solution can be 5wt%, 8wt%, 10wt%, 12wt%, 15wt%, 17wt%, 19wt%, 20wt%, or within a range composed of the above any values.

[0074] In some optional embodiments, the second solution of 2) is one or a mixture of two selected from ammonia water, hydrochloric acid aqueous solution, sodium chloride aqueous solution, and ammonium chloride aqueous solution. The concentration of the second solution is 5wt% or less, for example, the concentration of the second solution can be 0.5wt%, lwt%, 1.4wt%, 1.8wt%, 2.3wt%, 2.7wt%, 3.1wt%, 3.6wt%, 4.5wt%, 4.9wt%, 5wt%, or within a range composed of the above any values.

[0075] In some optional embodiments, in 3), the weight ratio of impregnation solution B2 to the alumina support is 0.5: 1 to 3: 1. For example, the weight ratio of impregnation solution B2 to the alumina support is 0.5: 1, 0.8: 1, 1 : 1, 1.2: 1, 1.5:1, 2.0: 1, 2.2: 1, 2.5: 1, 2.8: 1, 3: 1, or within a range composed of the above any values. In some optional embodiments, in 3), the impregnation time is in a range from 0.5 hours to 12 hours, the impregnation temperature is in a range from 20°C to 80°C, further optionally, the impregnation time is in a range from 0.5 hours to 4 hours, the impregnation temperature is in a range from 20°C to 40°C. For example, the immersion time can be 0.5 hours, 1 hour, 3 hours, 5 hours, 7 hours, 9 hours, 10 hours, 12 hours, or within the range of any of the above values. The impregnation temperature can be 20°C, 30°C, 40°C, 50 °C, 60°C, 70°C, 80°C, or within a range composed of the above any values.

[0076] In some optional implementation methods, in 4), the drying time can be from 2 hours to 24 hours, the drying temperature can be from 80°C to 120°C, the calcining time can be from 2 hours to 24 hours, and the calcining temperature can be from 120°C to 200°C. There is no need to specify the drying and calcination atmosphere, which can be air or nitrogen atmosphere. For example, the drying time can be 2 hours, 5 hours, 8 hours, 10 hours, 12 hours, 16 hours, 18 hours, 24 hours, or within the range of any of the above values. The drying temperature can be 80°C, 85°C, 90°C, 100°C, 110°C, 120°C, or within any range composed of the above values. The calcination time can be 2 hours, 5 hours, 8 hours, 10 hours, 12 hours, 16 hours, 18 hours, 24 hours, or within any range composed of the above values. The calcination temperature can be 80°C, 85°C, 90°C, 100°C, 110°C, or within any range composed of the above values.

[0077] In a third aspect, the present application also provides use of the above catalyst or the catalyst prepared by the above method in the production of dimethyl carbonate through gas-phase carbonylation reaction.

[0078] In some optional embodiments, in the presence of the catalyst provided in the present application, methyl nitrite reacts with carbon monoxide to prepare dimethyl carbonate.

[0079] In the use of the catalyst provided in the present application in the production of dimethyl carbonate through gas-phase carbonylation reaction, due to the specific composition of the catalyst, the catalyst has high activity, high selectivity, and long lifespan; the initial space-time yield is 600g / L-h-1or more, and the selectivity is 97% or more; and after running for 500 hours, the space-time yield is 590g / L-h-1, and the selectivity is 96% or more.

[0080] In some optional embodiments, in the use for preparing dimethyl carbonate, the reaction temperature is in a range from 80°C to 130°C. For example, the reaction temperature can be 80°C, 85°C, 90°C, 100°C, 110°C, 130°C, or within any range composed of the above values.

[0081] In some optional embodiments, in the use for preparing dimethyl carbonate, the reaction pressure is in a range from O. IMpa to l.OMpa, for example, the pressure can be O. IMPa, 0.3MPa, 0.5MPa, 0.7MPa, 0.9MPa, l.OMPa, or within any range composed of the above values.

[0082] In some optional embodiments, in the use for preparing dimethyl carbonate, the space velocity is in a range from 500h-1to 20,000 h’1. For example, the space velocity can be 500h-1, 800h , 1200b’1, 2000b-1, 300011’1, 50001T1, 8000b’1, 12000b’1, 16000b-1, 18000b’1, 20000b-1, or within any range composed of the above values.

[0083] The following provides a further detailed description of the present application in conjunction with specific examples, which cannot be understood as limiting the scope of protection claimed by the present application.

[0084] The analysis of the content of the organic compound substances (including dimethyl carbonate, methanol, methyl nitrite, dimethyl oxalate, etc.) in the following raw materials and products was carried out using gas chromatography 8090 manufactured by Agilent Technologies Inc., and it is equipped with HP-VOC capillary columns manufactured by Agilent Technologies Inc.

[0085] The acid amount of the alumina support is measured using the ammonia gas - temperature programmed desorption method, and the specific method is as follows: the acid amount of the catalyst was measured using an ammonia gas - temperature programmed desorption device. 0.2g of the alumina support was accurately weighed and placed in a quartz sample cell. Under an argon atmosphere, the sample cell was heated to 500°C for 5 hours at a constant temperature for sample pretreatment. Then, the sample cell was cooled to 50°C to adsorb ammonia gas until it reached saturation. Then, vacuum degassing treatment was carried out at 50°C for 30 minutes. Then, under an argon atmosphere, the sample cell was heated up to 600°C according to the program at a heating rate of 10°C / min to obtain the ammonia desorption curve. After peaks separation, they are integrated separately to obtain the acid amount data. Example 1

[0086] This example provides a catalyst, whose composition and preparation method are as follows.

[0087] (1) Preparation of alumina support: 1200g of ammonium nitrate aqueous solution with a concentration of 2wt% was prepared, and 300g of commercially available alumina support (i.e., alumina matrix, wherein alumina was spherical particles with a particle diameter of about 3mm, a specific surface area of 169m2 / g, a Na content of 650ppm, a Si content of 400ppm, and a ratio of the acid amount at low temperature (100°C to 310°C) to the acid amount at high temperature (310°C to 550°C) measured by the ammonia gas-Temperature Programmed Desorption (NHa-TPD) method of 0.35, the same below) were dispersed into the above ammonium nitrate solution, refluxed at 50°C for 2 hours, filtered, washed with deionized water for 5 times, dried overnight in an oven at 110°C, and then calcined at 200°C for 5 hours to obtain an alumina support precursor. 105g of potassium nitrate solution with a concentration of 5wt% was prepared, then the above alumina support precursor after calcination was dispersed into the potassium nitrate solution, immersed at room temperature for 2 hours, dried overnight in an oven at 80°C, and then calcined at 500°C for 5 hours to obtain an alumina support with a Na content of lOOppm, a K content of 5,000ppm, and a Si content of 140ppm (the elemental composition of which was analyzed using the AxiosMax type X-ray fluorescence spectrometer produced by PANalytial company in the Netherlands, the same below). The ratio of the acid amount at low temperature (100°C to 310°C) to the acid amount at high temperature (310°C to 550°C) of the prepared alumina support measured by NHa-TPD method was 5.0.

[0088] (2) Preparation of impregnation solution: 6.9g of PdCh and 13.4g of CuCh^EfcO were added and dissolved in 100g of 10% ammonia water, and 200g of 5% ammonia water was added therein and mixed to obtain the impregnation solution.

[0089] (3) 500g of the alumina support obtained in (1) was immersed in the impregnation solution obtained in (2), equal-volume impregnation was performed at room temperature, the materials were dried at 80°C for 12 hours, and calcined at 200°C for 2 hours to obtain catalyst Cl.

[0090] Catalyst evaluation: the catalyst Cl obtained above was evaluated in a fixed bed reactor, and the reaction conditions were set as follows: the loading amount of the catalyst was 20mL; the pressure was 0.6MPaG; the reaction temperature was 110°C; the reaction space velocity WHSV was 4000h-1; and the volume fraction of various components in the reactant raw materials was: 14% of CO, 15% of methyl nitrite (MN), and 71% of N2. After the carbonylation reaction, the reaction products were cooled at 5°C for gas-liquid separation, and the compositions of the gas phase and liquid phase products were analyzed to calculate the catalyst's space-time yield (STY) and DMC selectivity (Sei (DMC)). 1000 ) wherein, m (DMC) is the weight of DMC product generated per hour, and V(cat) is the volume of catalyst loaded; wherein, n(DMC) represents the amount of substance (mol) of dimethyl carbonate, n(DMO) represents the amount of substance (mol) of dimethyl oxalate, n(MF) represents the amount of substance (mol) of methyl formate, and n(ML) represents the amount of substance (mol) of methylal.

[0091] After testing, the initial space-time yield of catalyst Cl after running for 8h is 600g / L-h , and the initial selectivity of DMC is 97.6%; the space-time yield of catalyst Cl after running for 500h is 597g / L-h'1, and the selectivity of DMC is 97.7%.

[0092] Example 2

[0093] This example provides a catalyst, whose composition and preparation method are as follows.

[0094] (1) Preparation of alumina support: 1795g of ammonium chloride aqueous solution with a concentration of lwt% was prepared, and 100g of commercially available alumina support (i.e., alumina matrix) were dispersed into the above ammonium chloride aqueous solution, refluxed at 70°C for 12 hours, filtered, washed with deionized water for 5 times, dried overnight in an oven at 110°C, and then calcined at 200°C for 5 hours to obtain an alumina support precursor. 200g of lithium nitrate solution with a concentration of 10wt% was prepared, then the above alumina support precursor after calcination was dispersed into the above lithium nitrate solution, immersed at room temperature for 4 hours, dried overnight in an oven at 110°C, and then calcined at 800°C for 4 hours to obtain an alumina support with a Na content of 240ppm, a Li content of 15,000ppm, and a Si content of 180ppm. The ratio of the acid amount at low temperature (100°C to 310°C) to the acid amount at high temperature (310°C to 550°C) of the prepared alumina support measured by NBL-TPD method was 4.4.

[0095] (2) Preparation of impregnation solution: 9.3g of PdCL and 16.9g of CuCh^EbO were added into 350g of 5% ammonia water, and mixed to obtain the impregnation solution.

[0096] (3) 500g of the alumina support obtained in (1) was immersed in the impregnation solution obtained in (2), equal-volume impregnation was performed at room temperature, the materials were dried at 80°C for 12 hours, and calcined at 200°C for 2 hours to obtain catalyst C2.

[0097] The catalyst evaluation step is the same as that in Example 1. The initial space-time yield after running for 8h of catalyst C2 is 730g / L-h-1, and the initial selectivity of DMC is 97.8%; the space-time yield after running for 500h of catalyst C2 is 725g / L’h'1, and the selectivity of DMC is 98%.

[0098] Example 3

[0099] This example provides a catalyst, whose composition and preparation method are as follows.

[0100] (1) Preparation of alumina support: 600g of ammonium carbonate aqueous solution with a concentration of 3wt% was prepared, and 100g of commercially available alumina support (i.e., alumina matrix) were dispersed into the ammonium carbonate solution above, refluxed at 60°C for 20 hours, filtered, washed with deionized water for 5 times, dried overnight in an oven at 110°C, and then calcined at 200°C for 5 hours to obtain an alumina support precursor. 200g of lithium nitrate solution with a concentration of 10wt% was prepared, then the above alumina support precursor after calcination was dispersed into the above lithium nitrate solution, immersed at room temperature for 3 hours, dried overnight in an oven at 110°C, and then calcined at 800°C for 4 hours to obtain an alumina support with a Na content of 210ppm, a K content of 30ppm, a Li content of 8, lOOppm, and a Si content of 167ppm. The ratio of the acid amount at low temperature (100°C to 310°C) to the acid amount at high temperature (310°C to 550°C) of the prepared alumina support measured by NH3-TPD method was 3.3.

[0101] (2) Preparation of impregnation solution: 6.9g of PdCh and 13.4g of CuCh^EbO were added into 360g of 5% ammonia water and mixed to obtain the impregnation solution.

[0102] (3) 500g of the alumina support obtained in (1) was immersed in the impregnation solution obtained in (2), equal-volume impregnation was performed at room temperature, dried at 80°C for 12 hours, and calcined at 200°C for 2 hours to obtain catalyst C3.

[0103] The catalyst evaluation step is the same as that in Example 1. The initial space-time yield after running for 8h of catalyst C3 is 670g / L-h-1, and the initial selectivity of DMC is 97.0%; after running for 500h, the space-time yield of catalyst C3 is 650g / L-h-1, and the selectivity of DMC is 96.8%.

[0104] Example 4

[0105] This example provides a catalyst, whose composition and preparation method are as follows.

[0106] (1) Preparation of alumina support: 1200g of ammonium nitrate aqueous solution with a concentration of 2wt% was prepared, and 300g of commercially available alumina support (i.e., alumina matrix) were dispersed into the ammonium nitrate aqueous solution above, refluxed at 50°C for 2 hours, filtered, washed with deionized water for 5 times, dried overnight in an oven at 110°C, and then calcined at 200°C for 5 hours to obtain an alumina support precursor. 154g of sodium nitrate solution with a concentration of 5wt% was prepared, then the above alumina support precursor after calcination was dispersed into the sodium nitrate solution, immersed at room temperature for 2 hours, dried overnight in an oven at 80°C, and then calcined at 500°C for 5 hours to obtain an alumina support with a Na content of 5,200ppm, and a Si content of 137ppm. The ratio of the acid amount at low temperature (100°C to 310°C) to the acid amount at high temperature (310°C to 550°C) of the prepared alumina support measured by NH3-TPD method was 4.1.

[0107] (2) Preparation of impregnation solution: 6.9g of PdCh and 13.4g of CuCh^EbO were added and dissolved in 100g of 10% ammonia water, and 200g of 5% ammonia water was added therein and mixed to obtain the impregnation solution.

[0108] (3) 500g of the alumina support obtained in (1) was immersed in the impregnation solution obtained in (2), equal-volume impregnation was performed at room temperature, dried at 80°C for 12 hours, and calcined at 200°C for 2 hours to obtain catalyst C4.

[0109] The catalyst evaluation step is the same as that in Example 1. The initial space-time yield after running for 8h of catalyst C4 is SlOg / L’h'1, and the initial selectivity of DMC is 97.5%; after running for 500h, the space-time yield of catalyst C4 is 457g / L-h-1, and the selectivity of DMC is 97.3%.

[0110] Example 5

[0111] This example provides a catalyst, whose composition and preparation method are as follows.

[0112] (1) Preparation of alumina support: the specific method is the same as that in Example 1.

[0113] (2) Preparation of impregnation solution: 6.9g of PdCh and 13.4g of CuCh^EEO were added into 300g of 6.67% ammonia water and dissolved to obtain the impregnation solution.

[0114] (3) 500g of the alumina support obtained in (1) was immersed in the impregnation solution obtained in (2), equal-volume impregnation was performed at room temperature, dried at 80°C for 12 hours, and calcined at 200°C for 2 hours to obtain catalyst C5.

[0115] The catalyst evaluation step is the same as that in Example 1. The initial space-time yield after running for 8h of catalyst C5 is SSOg / L’h'1, and the initial selectivity of DMC is 97.6%; after running for 500h, the space-time yield of catalyst C5 is 555g / L-h_1, and the selectivity of DMC is 97.5%.

[0116] Example 6

[0117] This example provides a catalyst, whose composition and preparation method are as follows.

[0118] (1) Preparation of alumina support: 1000g of ammonium nitrate aqueous solution with a concentration of 2wt% was prepared, and 300g of commercially available alumina support (i.e., alumina matrix) were dispersed into the ammonium nitrate solution above, refluxed at 40°C for 2 hours, filtered, washed with deionized water for 5 times, dried overnight in an oven at 110°C, and then calcined at 200°C for 5 hours to obtain an alumina support precursor. 105g of potassium nitrate solution with a concentration of 2wt% was prepared, then the above alumina support precursor after calcination was dispersed into the potassium nitrate solution, immersed at room temperature for 2 hours, dried overnight in an oven at 80°C, and then calcined at 500°C for 5 hours to obtain an alumina support with a Na content of 120ppm, a K content of 2,500ppm, and a Si content of 160ppm. The ratio of the acid amount at low temperature (100°C to 310°C) to the acid amount at high temperature (310°C to 550°C) of the prepared alumina support measured by Nfh-TPD method was 2.5.

[0119] (2) Preparation of impregnation solution: 6.9g of PdCh and 13.4g of CuCh^EEO were added and dissolved in 100g of 10% ammonia water, and 200g of 5% ammonia water was added therein and mixed to obtain the impregnation solution.

[0120] (3) 500g of the alumina support obtained in (1) was immersed in the impregnation solution obtained in (2), equal-volume impregnation was performed at room temperature, dried at 80°C for 12 hours, and calcined at 200°C for 2 hours to obtain catalyst C6.

[0121] The catalyst evaluation step is the same as that in Example 1. The initial space-time yield after running for 8h of catalyst C6 is 570g / L-h-1, and the initial selectivity of DMC is 94.6%; after running for 500h, the space-time yield of catalyst C6 is 545g / L-h-1, and the selectivity of DMC is 94.3%.

[0122] Example 7

[0123] This example provides a catalyst, whose composition and preparation method are as follows.

[0124] (1) Preparation of alumina support: the specific method is the same as that in Example 1.

[0125] (2) Preparation of impregnation solution: 6.9g of PdCh and 15.5g of Ni(NC>3)2 were added and dissolved in 100g of 10% ammonia water, and 200g of 5% ammonia water was added therein and mixed to obtain the impregnation solution.

[0126] (3) 500g of the alumina support obtained in (1) was immersed in the impregnation solution obtained in (2), equal-volume impregnation was performed at room temperature, dried at 80°C for 12 hours, and calcined at 200°C for 2 hours to obtain catalyst C7.

[0127] The catalyst evaluation step is the same as that in Example 1. The initial space-time yield after running for 8h of catalyst C7 is 610g / L-h , and the initial selectivity of DMC is 97.5%; after running for 500h, the space-time yield of catalyst C7 is 600g / L-h , and the selectivity of

[0128] DMC is 97.5%.

[0129] Example 8

[0130] This example provides a catalyst, whose composition and preparation method are as follows.

[0131] (1) Preparation of alumina support: the specific method is the same as that in Example 1.

[0132] (2) Preparation of impregnation solution: 6.9g of PdCh and 13.4g of CuCh^EbO were added and dissolved in 200g of 10% ammonia water, and 200g of 5% ammonia chloride aqueous solution was added therein and mixed to obtain the impregnation solution.

[0133] (3) 500g of the alumina support obtained in (1) was immersed in the impregnation solution obtained in (2), equal-volume impregnation was performed at room temperature, dried at 80°C for 12 hours, and calcined at 200°C for 2 hours to obtain catalyst C8.

[0134] The catalyst evaluation step is the same as that in Example 1. The initial space-time yield after running for 8h of catalyst C8 is 615g / L-h_1, and the initial selectivity of DMC is 97.4%; after running for 500h, the space-time yield of catalyst C8 is 608g / L-h_1, and the selectivity of DMC is 97.3%.

[0135] Example 9

[0136] This example provides a catalyst, whose composition and preparation method are as follows.

[0137] (1) Preparation of alumina support: 1200g of ammonium nitrate aqueous solution with a concentration of 2wt% was prepared, and 300g of commercially available alumina support (i.e., alumina matrix) were dispersed into the ammonium nitrate solution above, refluxed at 80°C for 10 hours, filtered, washed with deionized water for 5 times, dried overnight in an oven at 110°C, and then calcined at 200°C for 5 hours to obtain an alumina support precursor. 105g of potassium nitrate solution with a concentration of 5wt% was prepared, then the above alumina support precursor after calcination was dispersed into the potassium nitrate solution, immersed at room temperature for 2 hours, dried overnight in an oven at 100°C, and then calcined at 650°C for 5 hours to obtain an alumina support with a Na content of 90ppm, a K content of 5,700ppm, and a Si content of llOppm. The ratio of the acid amount at low temperature (100°C to 310°C) to the acid amount at high temperature (310°C to 550°C) of the prepared alumina support measured by NH3-TPD method was 5.5.

[0138] (2) Preparation of impregnation solution: 6.9g of PdCh and 13.4g of CuCh^EbO were added and dissolved in 100g of 10% ammonia water, and 200g of 5% ammonia water was added therein and mixed to obtain the impregnation solution.

[0139] (3) 500g of the alumina support obtained in (1) was immersed in the impregnation solution obtained in (2), equal-volume impregnation was performed at room temperature, dried at 80°C for 12 hours, and calcined at 200°C for 2 hours to obtain catalyst C9.

[0140] The catalyst evaluation step is the same as that in Example 1. The initial space-time yield after running for 8h of catalyst C9 is 604g / L-h-1, and the initial selectivity of DMC is 97.7%; after running for 500h, the space-time yield of catalyst C9 is 600g / L-h , and the selectivity of DMC is 97.8%.

[0141] Example 10

[0142] This example provides a catalyst, whose composition and preparation method are as follows.

[0143] (1) Preparation of alumina support: 500g of ammonium nitrate aqueous solution with a concentration of lwt% was prepared, and 300g of commercially available alumina support (i.e., alumina matrix) were dispersed into the ammonium nitrate solution above, refluxed at 40°C for 2 hours, filtered, washed with deionized water for 5 times, dried overnight in an oven at 110°C, and then calcined at 200°C for 5 hours to obtain an alumina support precursor. 105g of potassium nitrate solution with a concentration of 5wt% was prepared, then the above alumina support precursor after calcination was dispersed into the potassium nitrate solution, immersed at room temperature for 2 hours, dried overnight in an oven at 100°C, and then calcined at 650°C for 5 hours to obtain an alumina support with a Na content of 320ppm, a K content of 5,700ppm, and a Si content of 180ppm. The ratio of the acid amount at low temperature (100°C to 310°C) to the acid amount at high temperature (310°C to 550°C) of the prepared alumina support measured by NH3-TPD method was 5.7.

[0144] (2) Preparation of impregnation solution: 6.9g of PdCh and 13.4g of CuCh^EbO were added and dissolved in 100g of 10% ammonia water, and 200g of 5% ammonia water was added therein and mixed to obtain the impregnation solution.

[0145] (3) 500g of the alumina support obtained in (1) was immersed in the impregnation solution obtained in (2), equal-volume impregnation was performed at room temperature, dried at 80°C for 12 hours, and calcined at 200°C for 2 hours to obtain catalyst CIO.

[0146] The catalyst evaluation step is the same as that in Example 1. The initial space-time yield after running for 8h of catalyst CIO is 589g / L-h-1, and the initial selectivity of DMC is 97.4%; after running for 500h, the space-time yield of catalyst CIO is 585g / L-h-1, and the selectivity of DMC is 97.2%.

[0147] Example 11

[0148] This example provides a catalyst, whose composition and preparation method are as follows.

[0149] (1) Preparation of alumina support: 1200g of ammonium nitrate aqueous solution with a concentration of 2wt% was prepared, and 150g of commercially available alumina support (i.e., alumina matrix) were dispersed into the ammonium nitrate solution above, refluxed at 80°C for 10 hours, filtered, washed with deionized water for 5 times, dried overnight in an oven at 110°C, and then calcined at 200°C for 5 hours to obtain an alumina support precursor. 145g of potassium nitrate solution with a concentration of 8wt% was prepared, then the above alumina support precursor after calcination was dispersed into the potassium nitrate solution, immersed at room temperature for 2 hours, dried overnight in an oven at 100°C, and then calcined at 650°C for 5 hours to obtain an alumina support with a Na content of 90ppm, a K content of 10,200ppm, and a Si content of llOppm. The ratio of the acid amount at low temperature (100°C to 310°C) to the acid amount at high temperature (310°C to 550°C) of the prepared alumina support measured by NEh-TPD method was 7.8.

[0150] (2) Preparation of impregnation solution: 6.9g of PdCh and 13.4g of CuCh^EbO were added and dissolved in 100g of 10% ammonia water, and 200g of 5% ammonia water was added therein and mixed to obtain the impregnation solution.

[0151] (3) 500g of the alumina support obtained in (1) was immersed in the impregnation solution obtained in (2), equal-volume impregnation was performed at room temperature, dried at 80°C for 12 hours, and calcined at 200°C for 2 hours to obtain catalyst Cll. The catalyst evaluation step is the same as that in Example 1. The initial space-time yield after running for 8h of catalyst Cll is 613g / L-h-1, and the initial selectivity of DMC is 97.7%; after running for 500h, the space-time yield of catalyst Cll is 610g / L-h-1, and the selectivity of DMC is 97.7%.

[0152] Example 12

[0153] This example provides a catalyst, whose composition and preparation method are as follows.

[0154] (1) Preparation of alumina support: 1200g of ammonium nitrate aqueous solution with a concentration of 2wt% was prepared, and 300g of commercially available alumina support (i.e., alumina matrix) were dispersed into the ammonium nitrate solution above, refluxed at 80°C for 10 hours, filtered, washed with deionized water for 5 times, dried overnight in an oven at 110°C, and then calcined at 200°C for 5 hours to obtain an alumina support precursor. 389g of lithium nitrate solution with a concentration of 10wt% was prepared, then the above alumina support precursor after calcination was dispersed into the lithium nitrate solution, immersed at room temperature for 2 hours, dried overnight in an oven at 100°C, and then calcined at 650°C for 5 hours to obtain an alumina support with a Na content of 90ppm, a Li content of 12,000ppm, and a Si content of llOppm. The ratio of the acid amount at low temperature (100°C to 310°C) to the acid amount at high temperature (310°C to 550°C) of the prepared alumina support measured by Nfh-TPD method was 12.1.

[0155] (2) Preparation of impregnation solution: 6.9g of PdCh and 13.4g of CuCh^EbO were added and dissolved in 100g of 10% ammonia water, and 200g of 5% ammonia water was added therein and mixed to obtain the impregnation solution.

[0156] (3) 500g of the alumina support obtained in (1) was immersed in the impregnation solution obtained in (2), equal-volume impregnation was performed at room temperature, dried at 80°C for 12 hours, and calcined at 200°C for 2 hours to obtain catalyst C12.

[0157] The catalyst evaluation step is the same as that in Example 1. The initial space-time yield after running for 8h of catalyst C12 is 710g / L’h'1, and the initial selectivity of DMC is 97.7%; after running for 500h, the space-time yield of catalyst C12 is 700g / L’h'1, and the selectivity of DMC is 97.6%. Example 13

[0158] This example provides a catalyst, whose composition and preparation method are as follows.

[0159] (1) Preparation of alumina support: 1200g of ammonium nitrate aqueous solution with a concentration of 2wt% was prepared, and 300g of commercially available alumina support (i.e., alumina matrix) were dispersed into the ammonium nitrate solution above, refluxed at 80°C for 10 hours, filtered, washed with deionized water for 5 times, dried overnight in an oven at 110°C, and then calcined at 200°C for 5 hours to obtain an alumina support precursor. 210g of potassium nitrate solution with a concentration of 10wt% was prepared, then the above alumina support precursor after calcination was dispersed into the potassium nitrate solution, immersed at room temperature for 2 hours, dried overnight in an oven at 100°C, and then calcined at 650°C for 5 hours to obtain an alumina support with a Na content of 90ppm, a K content of 24,000ppm, and a Si content of llOppm. The ratio of the acid amount at low temperature (100°C to 310°C) to the acid amount at high temperature (310°C to 550°C) of the prepared alumina support measured by NBE-TPD method was 14.5.

[0160] (2) Preparation of impregnation solution: 6.9g of PdCh and 13.4g of CuCh^EEO were added and dissolved in 100g of 10% ammonia water, and 200g of 5% ammonia water was added therein and mixed to obtain the impregnation solution.

[0161] (3) 500g of the alumina support obtained in (1) was immersed in the impregnation solution obtained in (2), equal-volume impregnation was performed at room temperature, dried at 80°C for 12 hours, and calcined at 200°C for 2 hours to obtain catalyst C13.

[0162] The catalyst evaluation step is the same as that in Example 1. The initial space-time yield after running for 8h of catalyst C13 is 595g / L-h-1, and the initial selectivity of DMC is 97.5%; after running for 500h, the space-time yield of catalyst C13 is 593g / L’h'1, and the selectivity of DMC is 97.3%.

[0163] Example 14

[0164] This example provides a catalyst, whose composition and preparation method are as follows.

[0165] (1) Preparation of alumina support: 1200g of ammonium nitrate aqueous solution with a concentration of 2wt% was prepared, and 300g of commercially available alumina support (i.e., alumina matrix) were dispersed into the ammonium nitrate solution above, refluxed at 80°C for 10 hours, filtered, washed with deionized water for 5 times, dried overnight in an oven at 110°C, and then calcined at 200°C for 5 hours to obtain an alumina support precursor. 80g of lithium nitrate solution with a concentration of 2wt% was prepared, then the above alumina support precursor after calcination was dispersed into the lithium nitrate solution, immersed at room temperature for 2 hours, dried overnight in an oven at 100°C, and then calcined at 650°C for 5 hours to obtain an alumina support with a Na content of 90ppm, a Li content of 450ppm, and a Si content of llOppm. The ratio of the acid amount at low temperature (100°C to 310°C) to the acid amount at high temperature (310°C to 550°C) of the prepared alumina support measured by NBL-TPD method was 1.5.

[0166] (2) Preparation of impregnation solution: 6.9g of PdCh and 13.4g of CuCh^EbO were added and dissolved in 100g of 10% ammonia water, and 200g of 5% ammonia water was added therein and mixed to obtain the impregnation solution.

[0167] (3) 500g of the alumina support obtained in (1) was immersed in the impregnation solution obtained in (2), equal-volume impregnation was performed at room temperature, dried at 80°C for 12 hours, and calcined at 200°C for 2 hours to obtain catalyst C14.

[0168] The catalyst evaluation step is the same as that in Example 1. The initial space-time yield after running for 8h of catalyst C14 is 595g / L-h-1, and the initial selectivity of DMC is 96.8%; after running for 500h, the space-time yield of catalyst C14 is 570g / L-h-1, and the selectivity of DMC is 96.6%.

[0169] Example 15

[0170] This example provides a catalyst, whose composition and preparation method are as follows.

[0171] (1) Preparation of alumina support: 1200g of ammonium nitrate aqueous solution with a concentration of 2wt% was prepared, and 300g of commercially available alumina support (i.e., alumina matrix) were dispersed into the ammonium nitrate solution above, refluxed at 80°C for 10 hours, filtered, washed with deionized water for 5 times, dried overnight in an oven at 110°C, and then calcined at 200°C for 5 hours to obtain an alumina support precursor. 200g of lithium nitrate solution with a concentration of 5wt% was prepared, then the above alumina support precursor after calcination was dispersed into the lithium nitrate solution, immersed at room temperature for 2 hours, dried overnight in an oven at 100°C, and then calcined at 650°C for 5 hours to obtain an alumina support with a Na content of 90ppm, a Li content of 3,070ppm, and a Si content of llOppm. The ratio of the acid amount at low temperature (100°C to 310°C) to the acid amount at high temperature (310°C to 550°C) of the prepared alumina support measured by NBL-TPD method was 3.0.

[0172] (2) Preparation of impregnation solution: 6.9g of PdCL and 13.4g of CuCh^EbO were added and dissolved in 100g of 10% ammonia water, and 200g of 5% ammonia water was added therein and mixed to obtain the impregnation solution.

[0173] (3) 500g of the alumina support obtained in (1) was immersed in the impregnation solution obtained in (2), equal-volume impregnation was performed at room temperature, dried at 80°C for 12 hours, and calcined at 200°C for 2 hours to obtain catalyst Cl 5.

[0174] The catalyst evaluation step is the same as that in Example 1. The initial space-time yield after running for 8h of catalyst C15 is 595g / L-h-1, and the initial selectivity of DMC is 97.1%; after running for 500h, the space-time yield of catalyst Cl 5 is 600g / L-h , and the selectivity of DMC is 97.0%.

[0175] Example 16

[0176] This example provides a catalyst, whose composition and preparation method are as follows.

[0177] (1) Preparation of alumina support: 1200g of ammonium nitrate aqueous solution with a concentration of 1.2wt% was prepared, and 300g of commercially available alumina support (i.e., alumina matrix) were dispersed into the ammonium nitrate solution above, refluxed at 40°C for 2 hours, filtered, washed with deionized water for 5 times, dried overnight in an oven at 110°C, and then calcined at 200°C for 5 hours to obtain an alumina support precursor. 450g of lithium chloride solution with a concentration of 10wt% was prepared, then the above alumina support precursor after calcination was dispersed into the lithium chloride solution, immersed at room temperature for 2 hours, dried overnight in an oven at 100°C, and then calcined at 650°C for 5 hours to obtain an alumina support with a Na content of 290ppm, a Li content of 22,500ppm, and a Si content of llOppm. The ratio of the acid amount at low temperature (100°C to 310°C) to the acid amount at high temperature (310°C to 550°C) of the prepared alumina support measured by NH3-TPD method was 11.8.

[0178] (2) Preparation of impregnation solution: 6.9g of PdCh and 13.4g of CuCh^EbO were added and dissolved in 100g of 10% ammonia water, and 200g of 5% ammonia water was added therein and mixed to obtain the impregnation solution.

[0179] (3) 500g of the alumina support obtained in (1) was immersed in the impregnation solution obtained in (2), equal-volume impregnation was performed at room temperature, dried at 80°C for 12 hours, and calcined at 200°C for 2 hours to obtain catalyst C16.

[0180] The catalyst evaluation step is the same as that in Example 1. The initial space-time yield after running for 8h of catalyst C16 is 640g / L-h-1, and the initial selectivity of DMC is 97.4%; after running for 500h, the space-time yield of catalyst C16 is 630g / L-h-1, and the selectivity of DMC is 97.3%.

[0181] Example 17

[0182] This example provides a catalyst, whose composition and preparation method are as follows.

[0183] (1) Preparation of alumina support: 400g of ammonium nitrate aqueous solution with a concentration of lwt% was prepared, and 300g of commercially available alumina support (i.e., alumina matrix) were dispersed into the ammonium nitrate solution above, refluxed at 40°C for 2 hours, filtered, washed with deionized water for 5 times, dried overnight in an oven at 110°C, and then calcined at 200°C for 5 hours to obtain an alumina support precursor. 80g of lithium nitrate solution with a concentration of 5wt% was prepared, then the above alumina support precursor after calcination was dispersed into the lithium nitrate solution, immersed at room temperature for 2 hours, dried overnight in an oven at 100°C, and then calcined at 650°C for 5 hours to obtain an alumina support with a Na content of 390ppm, a Li content of l,100ppm, and a Si content of 280ppm. The ratio of the acid amount at low temperature (100°C to 310°C) to the acid amount at high temperature (310°C to 550°C) of the prepared alumina support measured by NH3-TPD method was 3.6.

[0184] (2) Preparation of impregnation solution: 6.9g of PdCh and 13.4g of CuCh^EbO were added and dissolved in 100g of 10% ammonia water, and 200g of 5% ammonia water was added therein and mixed to obtain the impregnation solution.

[0185] (3) 500g of the alumina support obtained in (1) was immersed in the impregnation solution obtained in (2), equal-volume impregnation was performed at room temperature, dried at 80°C for 12 hours, and calcined at 200°C for 2 hours to obtain catalyst C17.

[0186] The catalyst evaluation step is the same as that in Example 1. The initial space-time yield after running for 8h of catalyst C17 is 620g / L’h'1, and the initial selectivity of DMC is 97.0%; after running for 500h, the space-time yield of catalyst C17 is 614g / L-h-1, and the selectivity of DMC is 96.9%.

[0187] Example 18

[0188] This example provides a catalyst, whose composition and preparation method are as follows.

[0189] (1) Preparation of alumina support: 2000g of ammonium nitrate aqueous solution with a concentration of 10wt% was prepared, and 300g of commercially available alumina support (i.e., alumina matrix) were dispersed into the ammonium nitrate solution above, refluxed at 80°C for 20 hours, filtered, washed with deionized water for 5 times, dried overnight in an oven at 110°C, and then calcined at 200°C for 5 hours to obtain an alumina support precursor. 105g of potassium nitrate solution with a concentration of 5wt% was prepared, then the above alumina support precursor after calcination was dispersed into the potassium nitrate solution, immersed at room temperature for 2 hours, dried overnight in an oven at 100°C, and then calcined at 650°C for 5 hours to obtain an alumina support with a Na content of 70ppm, a K content of 5,700ppm, and a Si content of 30ppm. The ratio of the acid amount at low temperature (100°C to 310°C) to the acid amount at high temperature (310°C to 550°C) of the prepared alumina support measured by NEh-TPD method was 5.4.

[0190] (2) Preparation of impregnation solution: 6.9g of PdCh and 13.4g of CuCh^EbO were added and dissolved in 100g of 10% ammonia water, and 200g of 5% ammonia water was added therein and mixed to obtain the impregnation solution.

[0191] (3) 500g of the alumina support obtained in (1) was immersed in the impregnation solution obtained in (2), equal-volume impregnation was performed at room temperature, dried at 80°C for 12 hours, and calcined at 200°C for 2 hours to obtain catalyst Cl 8.

[0192] The catalyst evaluation step is the same as that in Example 1. The initial space-time yield after running for 8h of catalyst Cl 8 is 602g / L-h-1, and the initial selectivity of DMC is 97.4%; after running for 500h, the space-time yield of catalyst C18 is 587g / L-h-1, and the selectivity of DMC is 97.3%.

[0193] Example 19

[0194] This example provides a catalyst, whose composition and preparation method are as follows.

[0195] (1) Preparation of alumina support: 1500g of ammonium nitrate aqueous solution with a concentration of 2wt% was prepared, and 300g of commercially available alumina support (i.e., alumina matrix) were dispersed into the ammonium nitrate solution above, refluxed at 80°C for 8 hours, filtered, washed with deionized water for 5 times, dried overnight in an oven at 110°C, and then calcined at 200°C for 5 hours to obtain an alumina support precursor. 115g of lithium chloride solution with a concentration of 5wt% was prepared, then the above alumina support precursor after calcination was dispersed into the lithium chloride solution, immersed at room temperature for 2 hours, dried overnight in an oven at 100°C, and then calcined at 650°C for 5 hours to obtain an alumina support with a Na content of 95ppm, a Li content of 2,900ppm, and a Si content of 105ppm. The ratio of the acid amount at low temperature (100°C to 310°C) to the acid amount at high temperature (310°C to 550°C) of the prepared alumina support measured by NFL-TPD method was 4.2.

[0196] (2) Preparation of impregnation solution: 6.9g of PdCh and 13.4g of CuCh^EbO were added and dissolved in 100g of 10% ammonia water, and 200g of 5% ammonia water was added therein and mixed to obtain the impregnation solution.

[0197] (3) 500g of the alumina support obtained in (1) was immersed in the impregnation solution obtained in (2), equal-volume impregnation was performed at room temperature, dried at 80°C for 12 hours, and calcined at 200°C for 2 hours to obtain catalyst C19.

[0198] The catalyst evaluation step is the same as that in Example 1. The initial space-time yield after running for 8h of catalyst C19 is 630g / L-h_1, and the initial selectivity of DMC is 97.4%; after running for 500h, the space-time yield of catalyst C19 is 618g / L-h_1, and the selectivity of DMC is 97.3%.

[0199] Example 20

[0200] This example provides a catalyst, whose composition and preparation method are as follows.

[0201] (1) Preparation of alumina support: 500g of ammonium carbonate aqueous solution with a concentration of lwt% was prepared, and 300g of commercially available alumina support (i.e., alumina matrix) were dispersed into the ammonium carbonate solution above, refluxed at 50°C for 2 hours, filtered, washed with deionized water for 5 times, dried overnight in an oven at 110°C, and then calcined at 200°C for 5 hours to obtain an alumina support precursor. 95g of potassium chloride solution with a concentration of 4wt% was prepared, then the above alumina support precursor after calcination was dispersed into the potassium chloride solution, immersed at room temperature for 2 hours, dried overnight in an oven at 100°C, and then calcined at 650°C for 5 hours to obtain an alumina support with a Na content of 280ppm, a K content of 5,800ppm, and a Si content of 185ppm. The ratio of the acid amount at low temperature (100°C to 310°C) to the acid amount at high temperature (310°C to 550°C) of the prepared alumina support measured by Nfh-TPD method was 5.8.

[0202] (2) Preparation of impregnation solution: 6.9g of PdCh and 13.4g of CuCh^EEO were added and dissolved in 100g of 10% ammonia water, and 200g of 5% ammonia water was added therein and mixed to obtain the impregnation solution.

[0203] (3) 500g of the alumina support obtained in (1) was immersed in the impregnation solution obtained in (2), equal-volume impregnation was performed at room temperature, dried at 80°C for 12 hours, and calcined at 200°C for 2 hours to obtain catalyst C20.

[0204] The catalyst evaluation step is the same as that in Example 1. The initial space-time yield after running for 8h of catalyst C20 is 632g / L’h'1, and the initial selectivity of DMC is 97.4%; after running for 500h, the space-time yield of catalyst C20 is 615g / L-h-1, and the selectivity of DMC is 97.4%.

[0205] Comparative Example 1

[0206] This comparative example provides a catalyst, whose composition and preparation method are as follows. (1) Preparation of impregnation solution: 6.9g of PdCh and 13.4g of CuCh^EEO were added and dissolved in 100g of 10% ammonia water, and 200g of 5% ammonia water was added therein and mixed to obtain the impregnation solution.

[0207] (2) 500g of commercially available alumina was immersed in the impregnation solution obtained in (1), equal -volume impregnation was performed at room temperature, dried at 80°C for 12 hours, and calcined at 200°C for 2 hours to obtain catalyst DI.

[0208] The catalyst evaluation step is the same as that in Example 1. The initial space-time yield after running for 8h of catalyst DI is OOg / L’h'1, and the initial selectivity of DMC is 90.9%; after running for 500h, the space-time yield of catalyst DI is SOOg / L’h'1, and the selectivity of DMC is 88.0%.

[0209] Comparative Example 2

[0210] This comparative example provides a catalyst, whose composition and preparation method are as follows:

[0211] (1) Preparation of alumina support: 1200g of ammonium nitrate aqueous solution with a concentration of 0.1 wt% was prepared, and 150g of commercially available alumina support (i.e., alumina matrix) were dispersed into the above ammonium nitrate solution, refluxed at 50°C for 2 hours, filtered, washed with deionized water for 5 times, dried overnight in an oven at 110°C, and then calcined at 200°C for 5 hours to obtain an alumina support precursor. 105g of potassium nitrate solution with a concentration of 0.2wt% was prepared, then the above alumina support precursor after calcination was dispersed into the potassium nitrate solution, immersed at room temperature for 2 hours, dried overnight in an oven at 80°C, and then calcined at 500°C for 5 hours to obtain an alumina support with a Na content of 460ppm, a K content of 260ppm, and a Si content of 340ppm. The ratio of the acid amount at low temperature (100°C to 310°C) to the acid amount at high temperature (310°C to 550°C) of the prepared alumina support measured by NEh-TPD method was 0.8.

[0212] (2) Preparation of impregnation solution: 6.9g of PdCh and 13.4g of CuCh^EbO were added and dissolved in 100g of 10% ammonia water, and 200g of 5% ammonia water was added therein and mixed to obtain the impregnation solution.

[0213] (3) 500g of the alumina support obtained in (1) was immersed in the impregnation solution obtained in (2), equal-volume impregnation was performed at room temperature, the materials were dried at 80°C for 12 hours, and calcined at 200°C for 2 hours to obtain catalyst D2.

[0214] The catalyst evaluation procedure is the same as that in Example 1. The initial space-time yield after running for 8h of catalyst D2 is 440g / L-h_1, and the initial selectivity of DMC is 92.1%; after running for 500h, the space-time yield of catalyst D2 is dOOg / L’h’1, and the selectivity of DMC is 91.7%.

[0215] In the present application, the differences between Comparative Example 1 and Examples 1-20 are that the catalyst provided in Comparative Example 1 is directly supported by commercially available alumina supports, and the content of the IA main group element, the content of silicon element, and the ratio of the acid amount at low temperature to the acid amount at high temperature were not regulated. The difference between Comparative Example 2 and Examples 1-20 is that although the content of the IA main group element, the content of silicon element, and the ratio of the acid amount at low temperature to the acid amount at high temperature of the alumina support were regulated in Comparative Example 2, the content of silicon element and the ratio of the acid amount at low temperature to the acid amount at high temperature after regulation are not within the scope limited in the present application. From the evaluation results of the above catalyst, it can be seen that the present application improves the stability of the alumina support, extends the service life of the catalyst, and improves the selectivity and activity of the catalysts at the same time by regulating the content of the IA main group element, the content of silicon element, and the ratio of the acid amount at low temperature to the acid amount at high temperature of the alumina support.

[0216] Obviously, the above examples are only provided for the purpose of clearly illustrating the examples, rather than limiting the implementations. For ordinary technical personnel in the field they belong to, different forms of changes or variations can be made based on the above explanation. It is not necessary and impossible to exhaustively list all implementations here. The obvious changes or variations arising from this are still within the scope of protection created by the present application.

Claims

Claims1. A catalyst, wherein the catalyst comprises an alumina support and an active component, wherein the alumina support comprises alumina, a IA main group element component and silicon element, based on the total weight of the alumina support, a total content of the IA main group element component is in a range from 510 ppm to 25,300ppm, and a content of silicon element is in a range from 10 ppm to 300 ppm; and a ratio of an acid amount at low temperature to an acid amount at high temperature of the alumina support is 1 or more.

2. The catalyst of claim 1, wherein, based on the total weight of the alumina support, a content of the IA main group element component is in a range from 3,000 ppm to 25,300 ppm, and a content of silicon element is in a range from 100 ppm to 200 ppm; and a ratio of an acid amount at low temperature to an acid amount at high temperature of the alumina support is in a range from 1 to 15.

3. The catalyst of claim 1 or 2, wherein the lA main group element component comprises sodium element and other IA main group elements, wherein a content of sodium element is in a range from 10 ppm to 300 ppm.

4. The catalyst of claim 1 or 2, wherein the acid amount is determined by the ammonia gas-Temperature Programmed Desorption (NHa-TPD) method, the acid amount at low temperature refers to the acid amount with peak positions between 100°C and 310°C, and the acid amount at high temperature refers to the acid amount with peak positions between 310°C and 550°C.

5. The catalyst of claim 1 or 2, wherein the active component comprises a platinum group metal component and an auxiliary active component; optionally, based on the total weight of the catalyst, a loading amount of the platinumgroup metal component is in a range from 0.1 wt% to 2wt%; further, optionally, based on the total weight of the catalyst, a loading amount of the platinum group metal component is in a range from 0.5wt% to 2wt%; and optionally, based on the total weight of the catalyst, a loading amount of the auxiliary active component is in a range from 0.1 wt% to 2wt%; further, optionally, based on the total weight of the catalyst, a loading amount of the auxiliary active component is in a range from 0.5wt% to 2wt%.

6. The catalyst of claim 5, wherein the platinum group metal component comprises Pd; and / or, the auxiliary active component comprise at least one of Cu, Co and Ni.

7. A method for preparing the catalyst of any one of claims 1 to 6, wherein the method comprises the following steps:51, using an aluminum oxide matrix or an alumina hydrate for ion exchange pretreatment, drying, calcining, impregnating in an aqueous solution containing other IA main group elements for ion exchange treatment, drying and calcining to obtain an alumina support; and52, using an impregnation solution containing the platinum group metal component and the auxiliary active component to impregnate the alumina support obtained in SI, drying and calcining to obtain the catalyst.

8. A method for preparing the catalyst of claim 7, wherein the ion exchange pretreatment comprises using an ammonium salt aqueous solution for ion exchange; and optionally, a weight concentration of the ammonium salt aqueous solution is in a range from lwt% to 3wt%, and the ion exchange pretreatment is carried out at a temperature ranging from 40 °C to 80 °C for a time period ranging from 1 hour to 24 hours.

9. A method for preparing the catalyst of claim 7, wherein in S2, a process for preparing the impregnation solution comprises: mixing the platinum group metal component, the auxiliary active component, and a first solution, adding water or a second solution to obtainthe impregnation solution; wherein, a concentration of the first solution is higher than a concentration of the second solution; optionally, the concentration of the first solution is in a range from 5wt% to 20wt%; further, optionally, the first solution comprises at least one of ammonia water, hydrochloric acid aqueous solution, sodium chloride aqueous solution and ammonium chloride aqueous solution; optionally, the second solution comprises at least one of ammonia water, hydrochloric acid aqueous solution, sodium chloride aqueous solution, and ammonium chloride aqueous solution; and / or, a weight ratio of the impregnation solution to the alumina support is in a range from 0.5: 1 to 3:l.

10. The method for preparing the catalyst of claim 7, wherein, in SI, the calcining is carried out at a temperature ranging from 200°C to 300°C for a time period ranging from 3 hours to 5 hours; and / or, the calcining in S2 is carried out at a temperature ranging from 120°C to 200°C for a time period ranging from 2 hours to 24 hours.

11. A use of the catalyst of any one of claims 1-6 or the catalyst prepared by the method of any one of claims 7 to 10 in the production of dimethyl carbonate through gas-phase carbonylation reaction.

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