Transalkylation catalyst, preparation method thereof and method for preparing 2, 6-dimethylnaphthalene

Abstract

The invention relates to the technical field of catalysts, and discloses a transalkylation catalyst and a preparation method thereof, and a method for preparing 2, 6-dimethylnaphthalene, the catalyst comprises a carrier and an active metal component loaded on the carrier; wherein the carrier comprises a twelve-membered ring molecular sieve and a binder; the active metal component is selected from at least one of transition metals; wherein the acid amount of the B acid in the catalyst is 100-400 [mu] mol / g, and the ratio of the acid amount of the B acid to the acid amount of the L acid is (1-3): 1. The catalyst is used for preparing 2, 6-dimethylnaphthalene through a transalkylation reaction, so that the reaction of naphthalene, methylnaphthalene and monocyclic aromatic hydrocarbon with methyl not only can have higher naphthalene / methylnaphthalene conversion rate, but also can have higher 2, 6-dimethylnaphthalene selectivity and yield, and the molecular sieve catalyst can be regenerated and used for multiple times and is good in stability.

Description

Technical Field

[0001] The invention relates to the technical field of catalysts, and in particular to an alkyl transfer catalyst and a preparation method thereof, and a method for preparing 2,6-dimethylnaphthalene. Background Art

[0002] Polyethylene naphthalate (PEN) is a new type of polyester material. Compared with traditional polyethylene terephthalate (PET), it has higher mechanical strength, heat resistance, chemical stability, gas barrier properties, and resistance to ultraviolet and radiation. It is suitable for electronic devices, packaging materials, instrumentation, aerospace and other industrial fields that have higher material requirements. The main route for PEN production is to oxidize 2,6-dimethylnaphthalene to produce naphthalene dicarboxylic acid, and then polymerize naphthalene dicarboxylic acid with ethylene glycol to produce PEN.

[0003] At present, the only industrial production route for 2,6-dimethylnaphthalene is the side chain alkylation reaction of o-xylene and butadiene by BP Amoco, followed by cyclization and dehydrogenation aromatization to obtain 1,5-dimethylnaphthalene, isomerization of 1,5-dimethylnaphthalene to obtain dimethylnaphthalene isomers, and then separation and purification to obtain more than 95wt% of 2,6-dimethylnaphthalene. This technical process is complex and the production cost is high, which restricts the large-scale application and development of PEN.

[0004] 2,6-dimethylnaphthalene can be synthesized in one step by alkylation reaction using naphthalene or methylnaphthalene as raw materials. The reaction process is simple and the raw material source is abundant. It is a low-cost production route for 2,6-dimethylnaphthalene with great potential. 3 As catalyst, durene, pentamethylbenzene and hexamethylbenzene as transfer alkylating agents, halogenated hydrocarbons as solvent, the transfer alkylation reaction of 2-methylnaphthalene was carried out at 40°C. The experimental results show that the yield of 2,6-dimethylnaphthalene can reach 28.74%. However, due to AlCl 3 The catalyst cannot be reused. During the separation process of the catalyst and the product, it will corrode the equipment and produce acidic wastewater, making the waste treatment process complicated.

[0005] CN101391937A discloses a method for preparing 2,6-dimethylnaphthalene by catalysis of ionic liquids. The method adopts halogenated alkyl imidazolium salt ionic liquids or halogenated alkyl pyridinium ionic liquids as catalysts, mixes methylnaphthalene, a transfer alkylating agent and a solvent, adds the ionic liquid thereto, reacts at 10-50°C for 0.5-8h under the protection of an inert gas, and then separates and obtains 2,6-dimethylnaphthalene. When the selectivity of 2,6-dimethylnaphthalene reaches 100%, the conversion rate of methylnaphthalene is generally lower than 13%, and the yield of 2,6-dimethylnaphthalene is low.

[0006] CN108341734A reports a method for preparing 2,6-dimethylnaphthalene by catalysis of magnetic ionic liquid. The method uses an ultrasonic reactor to carry out an alkyl transfer reaction with 1-methylnaphthalene, 2-methylnaphthalene and mesitylene as raw materials. The yield of 2,6-dimethylnaphthalene can reach 37%, but the reactor reaction efficiency is low and the catalyst separation and recovery are difficult.

[0007] CN1762932A discloses a method for generating 2,6-dimethylnaphthalene by transalkylation reaction of 2-methylnaphthalene with trimethylbenzene, tetramethylbenzene and pentamethylbenzene under supercritical reaction conditions using modified molecular sieve as catalyst. The reaction results show that the conversion rate of 2-methylnaphthalene is 52%, but the selectivity of 2,6-dimethylnaphthalene is low, and the reaction temperature and pressure are high, resulting in high energy consumption.

[0008] In summary, the methods for preparing 2,6-dimethylnaphthalene by transalkylation in the prior art all have problems in energy consumption, yield, stability, etc., which limits the industrialization of preparing 2,6-dimethylnaphthalene by transalkylation. Summary of the invention

[0009] The purpose of the present invention is to overcome the problems of high energy consumption and low yield in the prior art of preparing 2,6-dimethylnaphthalene by an alkylation translocation method, and to provide an alkylation translocation catalyst and a preparation method thereof, as well as a method for preparing 2,6-dimethylnaphthalene. The catalyst is used in catalyzing the alkylation translocation reaction to prepare 2,6-dimethylnaphthalene, and has excellent low-temperature activity, high reactant conversion rate and good product selectivity.

[0010] In order to achieve the above object, the present invention provides an alkyl transfer catalyst, which comprises a carrier and an active metal component supported on the carrier; wherein the carrier comprises a twelve-membered ring molecular sieve and a binder; the active metal component is selected from at least one of transition metals;

[0011] The amount of B acid in the catalyst is 100-400 μmol / g, and the ratio of the amount of B acid to the amount of L acid is 1-3:1.

[0012] The second aspect of the present invention provides a method for preparing the above-mentioned transalkylation catalyst, comprising:

[0013] (1) mixing the twelve-membered ring molecular sieve with a binder precursor, and then forming and drying the mixture to obtain a carrier precursor;

[0014] (2) contacting the carrier precursor with an acid solution for heat treatment, and then performing a first drying and a first calcination;

[0015] (3) impregnating the first calcined product with a solution containing an active metal component precursor in the presence of ultrasound, and then performing a second drying and a second calcination;

[0016] Wherein, the active metal component is selected from at least one of transition metals, preferably at least one of Cu, Fe and Zn.

[0017] The third aspect of the present invention provides a method for preparing 2,6-dimethylnaphthalene, the method comprising: contacting a reaction raw material with a transalkylation agent in the presence of a catalyst under liquid phase conditions;

[0018] Wherein, the reaction raw material is selected from at least one of naphthalene, 1-methylnaphthalene and 2-methylnaphthalene; the transfer alkylating agent is a methyl-substituted monocyclic aromatic hydrocarbon;

[0019] The catalyst is the transalkylation catalyst provided in the first aspect.

[0020] The transalkylation catalyst provided by the present invention adopts a carrier containing a twelve-membered ring molecular sieve to load a transition metal. The special pore structure of the twelve-membered ring molecular sieve and the synergistic effect of the suitable B acid and L acid content are used in the transalkylation reaction to prepare 2,6-dimethylnaphthalene, so that the reaction of naphthalene, methylnaphthalene and monocyclic aromatic hydrocarbons with methyl groups can not only have a high naphthalene / methylnaphthalene conversion rate, but also have a high 2,6-dimethylnaphthalene selectivity and yield. The molecular sieve catalyst can be regenerated and used multiple times, and has good stability. Further controlling the catalyst to have a suitable number of pores and pore size can further improve the low-temperature activity, conversion rate and selectivity of the catalyst.

[0021] The method for preparing 2,6-dimethylnaphthalene provided by the present invention can be carried out under mild liquid phase conditions, has low energy consumption, simple raw materials, and a multiphase continuous reaction. The method can be applied to a fixed bed, is simple to operate, and is suitable for industrial promotion. In a preferred case, no additional solvent needs to be introduced during the reaction process, and the catalyst can be repeatedly regenerated and used, which is beneficial to improving the economy of the reaction process and reducing costs. DETAILED DESCRIPTION

[0022] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0023] The first aspect of the present invention provides an alkyl transfer catalyst, the catalyst comprising a carrier and an active metal component supported on the carrier; wherein the carrier comprises a twelve-membered ring molecular sieve and a binder; the active metal component is selected from at least one of transition metals;

[0024] The amount of B acid in the catalyst is 100-400 μmol / g, and the ratio of the amount of B acid to the amount of L acid is 1-3:1.

[0025] The inventors of the present invention have found in their research that by using a carrier containing a twelve-membered ring molecular sieve to load a transition metal, the special pore structure of the twelve-membered ring molecular sieve and the synergistic effect of the suitable Br acid and L acid content can be used in the transalkylation reaction to prepare 2,6-dimethylnaphthalene, so that the reaction of naphthalene, methylnaphthalene and monocyclic aromatic hydrocarbons with methyl groups can not only have a higher naphthalene / methylnaphthalene conversion rate, but also have a higher 2,6-dimethylnaphthalene selectivity and yield.

[0026] According to some preferred embodiments of the present invention, the acid amount of B acid in the catalyst is 150-350 μmol / g, more preferably 180-250 μmol / g.

[0027] According to some preferred embodiments of the present invention, in the catalyst, the ratio of the acid amount of B acid to the acid amount of L acid is 1.2-3:1, for example, it can be 1.2:1, 1.5:1, 1.8:1, 2:1, 2.1:1, 2.2:1, 2.3:1, 2.4:1, 2.5:1, 2.6:1, 2.7:1, 2.8:1, 2.9:1, 3:1 and other typical but non-limiting ratios or ranges therebetween. Preferably, in the catalyst, the ratio of the acid amount of B acid to the acid amount of L acid is 2-2.8:1. In the above preferred case, it is beneficial to further improve the low temperature activity of the catalyst and improve the product selectivity and yield.

[0028] In the present invention, the contents of B acid and L acid of the catalyst are measured by pyridine probe infrared spectroscopy method.

[0029] According to the present invention, preferably, the specific surface area of ​​the catalyst is 250-700m 2 / g, preferably 300-650m 2 / g.

[0030] According to the present invention, preferably, the pore volume of the catalyst is 0.28-0.7 mL / g, preferably 0.3-0.68 mL / g.

[0031] In the present invention, the specific surface area and pore volume of the catalyst are measured by BET total analysis method.

[0032] The present invention has a wide selection range for the twelve-membered ring molecular sieve, for example, it can be at least one of Y molecular sieve, Beta molecular sieve, MCM-22 molecular sieve, MCM-56 molecular sieve, SAPO-5 molecular sieve, SAPO-37 molecular sieve and SAPO-40 molecular sieve. In a further preferred case, the twelve-membered ring molecular sieve is selected from at least one of Y molecular sieve, Beta molecular sieve and SAPO-5 molecular sieve. The use of the above-mentioned preferred molecular sieve types is conducive to the diffusion of reactants into the pores and contact with the acid center, thereby further improving the catalytic activity of the catalyst and improving the yield of the target product.

[0033] According to the present invention, preferably, the molar ratio of silicon oxide / aluminum oxide of the twelve-membered ring molecular sieve is 0.1-30, preferably 0.8-25. In the present invention, the molar ratio of silicon oxide / aluminum oxide of the twelve-membered ring molecular sieve is obtained by X-ray fluorescence spectrometry (XRF) method.

[0034] The present invention has no particular limitation on the type of binder in the carrier. Any conventional binder that can be used for catalyst carriers in the art can be applied to the present invention, for example, it can be at least one of alumina, kaolin, attapulgite, bentonite, diatomaceous earth and silicon dioxide. In order to further improve the catalytic activity and strength of the catalyst, preferably, the binder is alumina.

[0035] According to some preferred embodiments of the present invention, based on the total amount of the carrier, the content of the twelve-membered ring molecular sieve is 60-80wt%, preferably 65-75wt%; the content of the binder is 20-40wt%, preferably 25-35wt%.

[0036] According to the present invention, the active metal component in the catalyst is selected from at least one of transition metals, for example, it can be at least one of Cu, Zn, Ag, Ni, Co, Fe, Mn, Cr, Mo, Ru, Rh, Pd, Pt, preferably at least one of Cu, Fe and Zn, more preferably Cu and / or Fe. The use of the above preferred active metal composition helps to further adjust the acidity of the molecular sieve, thereby improving the catalytic activity and selectivity of the catalyst.

[0037] According to the present invention, preferably, based on the total amount of the catalyst, the content of the carrier is 90-99.9wt%, preferably 92-99wt%, and the content of the active metal component in terms of element is 0.1-10wt%, preferably 1-8wt%. In the above preferred case, it is beneficial to obtain the desired acidity and pore distribution.

[0038] In the present invention, the content of each component in the catalyst is analyzed by X-ray fluorescence spectroscopy (XRF) method.

[0039] The second aspect of the present invention provides a method for preparing the above-mentioned transalkylation catalyst, comprising:

[0040] (1) mixing the twelve-membered ring molecular sieve with a binder precursor, and then forming and drying the mixture to obtain a carrier precursor;

[0041] (2) contacting the carrier precursor with an acid solution for heat treatment, and then performing a first drying and a first calcination;

[0042] (3) impregnating the first calcined product with a solution containing an active metal component precursor in the presence of ultrasound, and then performing a second drying and a second calcination;

[0043] Wherein, the active metal component is selected from at least one of transition metals, preferably at least one of Cu, Fe and Zn.

[0044] In the present invention, the twelve-membered ring molecular sieve has the same definition as in the above text, which will not be described in detail. Preferably, the twelve-membered ring molecular sieve is a hydrogen twelve-membered ring molecular sieve.

[0045] Preferably, the specific surface area of ​​the twelve-membered ring molecular sieve is 280-740 m 2 / g, preferably 340-730m 2 / g.

[0046] Preferably, the pore volume of the hydrogen-type twelve-membered ring molecular sieve is 0.26-0.66 mL / g, preferably 0.28-0.64 mL / g.

[0047] In the present invention, the binder precursor refers to any substance that can be used to obtain the binder by calcination, which is well known to those skilled in the art. For example, the precursor of aluminum oxide may be pseudo-boehmite.

[0048] According to some preferred embodiments of the present invention, the dry basis mass ratio of the twelve-membered ring molecular sieve to the binder precursor is 60-80:20-40, preferably 65-75:25-35.

[0049] The present invention has no particular limitation on the molding method, and those skilled in the art can select the molding method according to actual needs, for example, extrusion molding can be used.

[0050] A peptizing agent may also be introduced during the molding process. According to some preferred embodiments of the present invention, step (1) comprises: mixing a twelve-membered ring molecular sieve, a binder precursor and a peptizing agent, and then molding and drying to obtain a carrier precursor. The present invention has no particular requirements for the specific type of the peptizing agent. Preferably, the peptizing agent is an aqueous solution of an acid, preferably an aqueous solution of at least one selected from nitric acid, acetic acid, citric acid, oxalic acid and formic acid. Preferably, the concentration of the acid in the peptizing agent is 1-5wt%.

[0051] Preferably, the ratio of the peptizing agent to the total mass of the twelve-membered ring molecular sieve and the binder precursor is 0.2-0.6:1.

[0052] According to some preferred embodiments of the present invention, the drying conditions in step (1) include: a temperature of 30-200° C., preferably 60-180° C.; and a time of 0.1-72 h, preferably 4-48 h.

[0053] In the present invention, preferably, the forming process does not include a calcination process.

[0054] In the present invention, the catalyst is adjusted to have appropriate B acid and L acid contents through the heat treatment in step (2) and the loading of active metal components in step (3), and the catalyst is further adjusted to have appropriate pore number and pore size.

[0055] According to some preferred embodiments of the present invention, in step (2), the acid solution is provided by an acid aqueous solution, and the concentration of the acid aqueous solution is 0.5-3 mol / L, preferably 0.5-2.5 mol / L.

[0056] The present invention has a wide range of choices for the type of acid, and conventional organic acids and / or inorganic acids in the art can be used. Preferably, the acid is selected from at least one of citric acid, ethylenediaminetetraacetic acid, malic acid, tartaric acid, sulfuric acid, phosphoric acid and nitric acid, preferably citric acid and / or phosphoric acid.

[0057] Preferably, relative to 1 g of the carrier precursor, the amount of the acid solution is 5-15 mL, preferably 8-12 mL.

[0058] According to some preferred embodiments of the present invention, the heat treatment temperature is 40-100° C., preferably 60-90° C., and the time is 5-24 hours, preferably 6-18 hours. The above preferred embodiments are beneficial to further optimize the acid distribution of the catalyst and improve the catalytic activity and selectivity of the catalyst.

[0059] According to some preferred embodiments of the present invention, the temperature of the first drying is 30-200° C., preferably 60-180° C., and the time is 0.1-72 h, preferably 4-48 h.

[0060] According to some preferred embodiments of the present invention, the temperature of the first calcination is 380-580° C., preferably 400-520° C., and the time is 0.5-20 h, preferably 3-12 h.

[0061] In the present invention, the impregnation in step (3) is carried out in the presence of ultrasound, and the first calcined product can be firstly impregnated in a solution containing an active metal component precursor, and then the ultrasound treatment is started.

[0062] The present invention has a wide range of choices for the active metal component precursor, and can use conventional soluble compounds of active metal components in the art, such as nitrates and / or chlorides of transition metals. The present invention has no special requirements for the concentration and dosage of the solution containing the active metal component precursor, and is based on the upper amount of the transition metal. Preferably, the concentration of the solution containing the active metal component precursor is 0.1-1 mol / L.

[0063] According to some preferred embodiments of the present invention, the ultrasonic conditions include: ultrasonic power density of 0.1-20 W / cm 2 , preferably 5-15W / cm 2 The above preferred embodiment is advantageous for uniform dispersion of active metal components.

[0064] According to the present invention, preferably, the immersion temperature is 40-100°C, preferably 60-90°C; and the immersion time is 5-24h, preferably 6-18h.

[0065] The present invention has no particular limitation on the conditions of the second drying, as long as the excess impregnation liquid can be removed. Preferably, the temperature of the second drying is 30-200° C., and the time is 0.1-72 hours.

[0066] Preferably, the second calcination is carried out at a temperature of 400-600° C. and for a time of 0.5-20 h.

[0067] According to the present invention, preferably, the second drying and the second calcining are performed under an inert atmosphere, and the inert atmosphere can be provided by nitrogen.

[0068] The third aspect of the present invention provides a method for preparing 2,6-dimethylnaphthalene, the method comprising: contacting a reaction raw material with a transalkylation agent in the presence of a catalyst under liquid phase conditions;

[0069] Wherein, the reaction raw material is selected from at least one of naphthalene, 1-methylnaphthalene and 2-methylnaphthalene; the transfer alkylating agent is a methyl-substituted monocyclic aromatic hydrocarbon;

[0070] The catalyst is the transalkylation catalyst described in the first aspect.

[0071] According to the present invention, preferably, the transfer alkylating agent is selected from any one or a mixture of toluene, xylene, trimethylbenzene and tetramethylbenzene. The xylene may be at least one of o-xylene, p-xylene and m-xylene; the trimethylbenzene may be at least one of unsymmetrical trimethylbenzene, 3-trimethylbenzene and mesitylene; the tetramethylbenzene may be at least one of unsymmetrical tetramethylbenzene, 3-trimethylbenzene and mesitylene.

[0072] The present invention has no special requirements for the source of the transfer alkylating agent, and it can also be provided by mixed C8 aromatics, mixed C9 aromatics, mixed C10 aromatics, etc. The mixed C8 aromatics, mixed C9 aromatics, and mixed C10 aromatics have the conventional definitions in the art, and the mixed C8 aromatics include xylene and ethylbenzene, the mixed C9 aromatics include trimethylbenzenes, methylethylbenzene and propylbenzene, and the mixed C10 aromatics include tetramethylbenzenes, diethylbenzene and methylpropylbenzene, etc. Preferably, the methyl-substituted aromatics (i.e., xylene, trimethylbenzenes or tetramethylbenzenes) in the mixed C8 aromatics, the mixed C9 aromatics, and the mixed C10 aromatics account for about 40-60 mol% respectively.

[0073] In the present invention, in the transfer alkylating agent, the molar ratio of toluene, xylene, trimethylbenzene and tetramethylbenzene is (0-10): (0-10): (0-10): (0-10).

[0074] According to some preferred embodiments of the present invention, the molar ratio of the reaction raw material to the transfer alkylating agent is 1:(1-10), preferably 1:(2-7).

[0075] According to the present invention, the method for preparing 2,6-dimethylnaphthalene can be carried out under mild liquid phase conditions, and when the reaction temperature is not higher than 400° C., it has a high raw material conversion rate and product selectivity, and the yield of 2,6-dimethylnaphthalene is high.

[0076] According to some preferred embodiments of the present invention, the liquid phase conditions include: reaction temperature of 150-400°C, preferably 250-350°C; reaction pressure of 0.5-5MPa, preferably 2.0-4.0MPa; weight hourly space velocity of the reaction raw materials of 0.1-5h -1 , preferably 0.5-3h -1 In the present invention, unless otherwise specified, the pressure refers to the gauge pressure. By adopting the above preferred embodiment, the reaction energy consumption can be further reduced and the economic efficiency of the reaction process can be improved while ensuring a high raw material conversion rate and product selectivity.

[0077] The present invention will be described in detail below through examples.

[0078] Unless otherwise specified, the raw materials used in the following examples and comparative examples are commercially available.

[0079] Example 1

[0080] (1) Take H-Beta molecular sieve with a silicon oxide / alumina molar ratio of 25 (specific surface area of ​​693 m 2 / g, pore volume of 0.56mL / g) and pseudo-boehmite (produced by Condea in Germany, brand Pural SB powder) are mixed in a dry basis mass ratio of 65:35, and diluted nitric acid with a concentration of 5% by mass is added in a mass ratio of dilute nitric acid to the above mixture of 1:2, and the mixture is extruded into strips, and then dried at 110°C for 4 hours to obtain a carrier precursor.

[0081] (2) The carrier precursor was placed in a citric acid solution with a concentration of 1 mol / L. The amount of the acid solution was 10 mL relative to 1 g of the carrier precursor. The solution was treated at 80° C. for 8 h, then dried at 110° C. for 4 h, and calcined at 520° C. for 5 h.

[0082] (3) The sample treated in step (2) was placed in 0.2 mol / L Cu(NO 3 ) 2 The solution was immersed and the immersed solution was ultrasonically treated with an ultrasonic power density of 10 W / cm 2 , the treatment time is 6h, and the temperature is 60℃.

[0083] (4) The sample treated in step (3) was dried at 110° C. for 4 hours under a nitrogen atmosphere and calcined at 560° C. for 5 hours to obtain catalyst A1. X-ray fluorescence spectroscopy (XRF) analysis showed that the Cu content in the catalyst was 2.13% by mass.

[0084] The acid composition, specific surface area and pore volume of the catalyst are shown in Table 1.

[0085] Example 2

[0086] The method of Example 1 was followed except that a HY molecular sieve having a silicon oxide / aluminum oxide molar ratio of 7 (specific surface area of ​​730 m 2 / g, pore volume of 0.33mL / g) to replace H-Beta molecular sieve, the obtained catalyst is recorded as A2. According to X-ray fluorescence spectroscopy (XRF) analysis, the Cu content in the catalyst is 2.42% by mass. The acid composition, specific surface area and pore volume of the catalyst are shown in Table 1.

[0087] Example 3

[0088] (1) Take H-Beta molecular sieve with a silicon oxide / alumina molar ratio of 25 (specific surface area of ​​693 m 2 / g, pore volume of 0.56mL / g) and pseudo-boehmite (produced by Condea in Germany, brand Pural SB powder) are mixed in a dry basis mass ratio of 70:30, and diluted nitric acid with a concentration of 5% by mass is added in a mass ratio of dilute nitric acid to the above mixture of 1:2, and the mixture is extruded into strips, and then dried at 110°C for 4 hours to obtain a carrier precursor.

[0089] (2) The carrier precursor was placed in a phosphoric acid solution with a concentration of 2 mol / L. The amount of the acid solution was 10 mL relative to 1 g of the carrier precursor. The solution was treated at 80° C. for 8 h, then dried at 110° C. for 4 h, and calcined at 520° C. for 5 h.

[0090] (3) The sample treated in step (2) was placed in 0.2 mol / L Cu(NO 3 ) 2 The solution was immersed and the immersed solution was ultrasonically treated with an ultrasonic power density of 10 W / cm 2 , the treatment time is 6h, and the temperature is 60℃.

[0091] (4) The sample treated in step (3) was dried at 110° C. for 4 hours under a nitrogen atmosphere and calcined at 560° C. for 5 hours to obtain catalyst A3. X-ray fluorescence spectroscopy (XRF) analysis showed that the Cu content in the catalyst was 2.16% by mass.

[0092] The acid composition, specific surface area and pore volume of the catalyst are shown in Table 1.

[0093] Example 4

[0094] (1) Take H-Beta molecular sieve with a silicon oxide / alumina molar ratio of 25 (specific surface area of ​​693 m 2 / g, pore volume of 0.56mL / g) and pseudo-boehmite (produced by Condea in Germany, brand Pural SB powder) are mixed in a dry basis mass ratio of 65:35, and diluted nitric acid with a concentration of 5% by mass is added in a mass ratio of dilute nitric acid to the above mixture of 1:2, and the mixture is extruded into strips, and then dried at 110°C for 4 hours to obtain a carrier precursor.

[0095] (2) The carrier precursor was placed in a 2 mol / L citric acid solution, with the amount of the acid solution being 10 mL relative to 1 g of the carrier precursor. The solution was treated at 80° C. for 8 h, then dried at 110° C. for 4 h, and calcined at 520° C. for 5 h.

[0096] (3) The sample treated in step (2) was placed in a 0.2 mol / L Fe(NO 3 ) 3 The solution was immersed and the immersed solution was ultrasonically treated with an ultrasonic power density of 10 W / cm 2, the treatment time is 6h, and the temperature is 60℃.

[0097] (4) The sample treated in step (3) was dried at 110° C. for 4 hours under a nitrogen atmosphere and calcined at 560° C. for 5 hours to obtain catalyst A4. X-ray fluorescence spectroscopy (XRF) analysis showed that the Cu content in the catalyst was 1.88% by mass.

[0098] The acid composition, specific surface area and pore volume of the catalyst are shown in Table 1.

[0099] Example 5

[0100] (1) Take HY molecular sieve with a silicon oxide / alumina molar ratio of 7 (specific surface area of ​​604 m 2 / g, pore volume of 0.32mL / g) and pseudo-boehmite (produced by Condea in Germany, brand Pural SB powder) are mixed in a dry basis mass ratio of 65:35, and diluted nitric acid with a concentration of 1% by mass is added in a mass ratio of dilute nitric acid to the above mixture of 1:2, and the mixture is extruded into strips, and then dried at 110°C for 4 hours to obtain a carrier precursor.

[0101] (2) The carrier precursor was placed in a citric acid solution with a concentration of 1 mol / L. The amount of the acid solution was 10 mL relative to 1 g of the carrier precursor. The solution was treated at 80° C. for 8 h, then dried at 110° C. for 4 h, and calcined at 520° C. for 5 h.

[0102] (3) The sample treated in step (2) was placed in a 0.2 mol / L Fe(NO 3 ) 3 The solution was immersed, and the immersed solution was ultrasonically treated with an ultrasonic power density of 5 W / cm 2 , the treatment time is 6h, and the temperature is 60℃.

[0103] (4) The sample treated in step (3) was dried at 110° C. for 4 hours under a nitrogen atmosphere and calcined at 560° C. for 5 hours to obtain catalyst A5. X-ray fluorescence spectroscopy (XRF) analysis showed that the Fe content in the catalyst was 1.93% by mass.

[0104] The acid composition, specific surface area and pore volume of the catalyst are shown in Table 1.

[0105] Example 6

[0106] The method of Example 1 was followed except that a SAPO-5 molecular sieve (specific surface area of ​​593 m2) with a silicon oxide / aluminum oxide molar ratio of 0.5 was used. 2 / g, pore volume of 0.28mL / g) to replace H-Beta molecular sieve, the obtained catalyst was recorded as A6. According to X-ray fluorescence spectroscopy (XRF) analysis, the Cu content in the catalyst was 1.42% by mass.

[0107] Comparative Example 1

[0108] The method of Example 1 was followed except that HZSM-5 molecular sieve (specific surface area 370 m 2 / g, pore volume of 0.20mL / g) to replace H-Beta molecular sieve, the obtained catalyst is recorded as DA1. According to X-ray fluorescence spectroscopy (XRF) analysis, the Cu content in the catalyst is 2.42% by mass. The acid composition, specific surface area and pore volume of the catalyst are shown in Table 1.

[0109] Comparative Example 2

[0110] The method of Example 1 was followed, except that the acid treatment in step (2) was not performed. The carrier precursor was dried at 110° C. for 4 hours, calcined at 520° C. for 5 hours, and then placed in 0.2 mol / L Cu(NO 3 ) 2 The solution was immersed, and the immersed solution was ultrasonically treated with an ultrasonic power density of 5 W / cm 2 , the treatment time is 6h, and the temperature is 60℃.

[0111] The treated sample was then dried at 110°C for 4 hours under a nitrogen atmosphere and calcined at 560°C for 5 hours to obtain catalyst DA2. X-ray fluorescence spectroscopy (XRF) analysis showed that the Cu content in the catalyst was 2.32% by mass. The acid composition, specific surface area and pore volume of the catalyst are shown in Table 1.

[0112] Comparative Example 3

[0113] (1) Take H-Beta molecular sieve with a silicon oxide / alumina molar ratio of 27 (specific surface area of ​​439 m 2 / g, pore volume of 0.50mL / g) and pseudo-boehmite (produced by Condea in Germany, brand Pural SB powder) are mixed in a dry basis mass ratio of 65:35, and diluted nitric acid with a concentration of 1% by mass is added in a mass ratio of dilute nitric acid to the above mixture of 1:2, and the mixture is extruded into strips, and then dried at 110°C for 4 hours to obtain a carrier precursor.

[0114] (2) The carrier precursor was placed in a citric acid solution with a concentration of 1 mol / L. The amount of the acid solution was 10 mL relative to 1 g of the carrier precursor. The catalyst was treated at 80°C for 8 hours, then dried at 110°C for 4 hours, and calcined at 520°C for 5 hours. Catalyst DA3 was obtained. The acid composition, specific surface area and pore volume of the catalyst are shown in Table 1.

[0115] Table 1

[0116]

[0117] Test Case

[0118] The catalysts prepared in the above examples and comparative examples were used in a fixed bed microreactor to carry out the transalkylation reaction of naphthalene / methylnaphthalene with monocyclic aromatic hydrocarbons having a methyl group. The reaction temperature was as shown in Table 2, the reaction pressure was 2.5 MPa, and the weight hourly space velocity was 1 h -1 The results of the 8-hour reaction are shown in Table 2.

[0119] In Table 2, the reaction evaluation results were calculated as follows:

[0120]

[0121]

[0122] 2,6-dimethylnaphthalene yield (%) = 2,6-dimethylnaphthalene selectivity × naphthalene / methylnaphthalene conversion × 100%.

[0123] Table 2

[0124]

[0125]

[0126] *The composition of the mixed C9 aromatic hydrocarbons includes: 60 mol% of trimethylbenzene, 20 mol% of methylethylbenzene, 15 mol% of n-propylbenzene, and 5 mol% of isopropylbenzene. The molar ratio of 2-methylnaphthalene to trimethylbenzene in the mixed C9 aromatic hydrocarbons is 1:5.

[0127] It can be seen from the results in Table 2 that the transalkylation catalyst prepared in the embodiment of the present invention has higher selectivity and yield of 2,6-dimethylnaphthalene, and good low-temperature activity. While ensuring a high raw material conversion rate and product selectivity, it is beneficial to reduce the reaction energy consumption and improve the economy of the reaction process.

[0128] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. A transalkylation catalyst, characterized in that: The catalyst comprises a carrier and an active metal component supported on the carrier; wherein the carrier comprises a twelve-membered ring molecular sieve and a binder; and the active metal component is selected from at least one of transition metals; The amount of B acid in the catalyst is 100-400 μmol / g, and the ratio of the amount of B acid to the amount of L acid is 1-3:

1.

2. The catalyst according to claim 1, wherein The amount of B acid in the catalyst is 150-350 μmol / g; and / or, the ratio of the acid amount of B acid to the acid amount of L acid is 1.2-3:1; And / or, the specific surface area of ​​the catalyst is 250-700m 2 / g, preferably 300-650m 2 / g; And / or, the pore volume of the catalyst is 0.28-0.7 mL / g, preferably 0.3-0.68 mL / g.

3. The catalyst according to claim 1 or 2, wherein The twelve-membered ring molecular sieve is selected from at least one of Y molecular sieve, Beta molecular sieve, MCM-22 molecular sieve, MCM-56 molecular sieve, SAPO-5 molecular sieve, SAPO-37 molecular sieve, and SAPO-40 molecular sieve, preferably at least one of Y molecular sieve, Beta molecular sieve, and SAPO-5 molecular sieve; Preferably, the molar ratio of silicon oxide to aluminum oxide of the twelve-membered ring molecular sieve is 0.1-30; and / or, the binder is selected from at least one of alumina, kaolin, attapulgite, bentonite, diatomaceous earth and silica, preferably alumina; And / or, based on the total amount of the carrier, the content of the twelve-membered ring molecular sieve is 60-80wt%, preferably 65-75wt%; the content of the binder is 20-40wt%, preferably 25-35wt%.

4. The catalyst according to any one of claims 1 to 3, wherein The active metal component is selected from at least one of Cu, Fe and Zn, more preferably Cu and / or Fe; Preferably, based on the total amount of the catalyst, the content of the carrier is 90-99.9wt%, preferably 92-99wt%, and the content of the active metal component in terms of element is 0.1-10wt%, preferably 1-8wt%.

5. The method for preparing the transalkylation catalyst according to any one of claims 1 to 4, comprising: (1) mixing the twelve-membered ring molecular sieve with a binder precursor, and then forming and drying the mixture to obtain a carrier precursor; (2) contacting the carrier precursor with an acid solution for heat treatment, and then performing a first drying and a first calcination; (3) impregnating the first calcined product with a solution containing an active metal component precursor in the presence of ultrasound, and then performing a second drying and a second calcination; Wherein, the active metal component is selected from at least one of transition metals, preferably at least one of Cu, Fe and Zn.

6. The preparation method according to claim 5, wherein: The twelve-membered ring molecular sieve is a hydrogen-type twelve-membered ring molecular sieve; Preferably, the specific surface area of ​​the twelve-membered ring molecular sieve is 280-740 m 2 / g, preferably 340-730m 2 / g; Preferably, the pore volume of the twelve-membered ring molecular sieve is 0.26-0.66 mL / g, preferably 0.28-0.64 mL / g; Preferably, the dry basis mass ratio of the twelve-membered ring molecular sieve to the binder precursor is 60-80:20-40, preferably 65-75:25-35; Preferably, the drying conditions in step (1) include: a temperature of 60-180° C. and a time of 4-48 hours.

7. The preparation method according to claim 5 or 6, wherein: The acid solution is provided by an acid aqueous solution, and the concentration of the acid aqueous solution is 0.5-3 mol / L; Preferably, the acid is selected from at least one of citric acid, ethylenediaminetetraacetic acid, malic acid, tartaric acid, sulfuric acid, phosphoric acid and nitric acid, preferably citric acid and / or phosphoric acid; Preferably, relative to 1g of the carrier precursor, the amount of the acid solution is 5-15mL, preferably 8-12mL; Preferably, the heat treatment temperature is 40-100°C and the time is 5-24h; Preferably, the first drying temperature is 30-200°C and the time is 0.1-72h; Preferably, the temperature of the first calcination is 380-580° C., and the time is 0.5-20 h.

8. The preparation method according to any one of claims 5 to 7, wherein: The ultrasonic conditions include: ultrasonic power density of 0.1-10W / cm 2 ; Preferably, the immersion temperature is 40-100°C and the time is 5-24h; Preferably, the second drying temperature is 30-200°C and the time is 0.1-72h; Preferably, the second calcination temperature is 400-600°C and the time is 0.5-20h; Preferably, the second drying and the second calcining are performed under an inert atmosphere.

9. A method for preparing 2,6-dimethylnaphthalene, characterized in that: The method comprises: contacting a reaction raw material with a transalkylation agent in the presence of a catalyst under liquid phase conditions; Wherein, the reaction raw material is selected from at least one of naphthalene, 1-methylnaphthalene and 2-methylnaphthalene; the transfer alkylating agent is a methyl-substituted monocyclic aromatic hydrocarbon; The catalyst is the transalkylation catalyst according to any one of claims 1 to 4.

10. The method according to claim 9, wherein: The transfer alkylating agent is selected from at least one of toluene, xylene, trimethylbenzene and tetramethylbenzene; Preferably, the molar ratio of the reaction raw material to the transalkylating agent is 1:(1-5); Preferably, the liquid phase conditions include: reaction temperature of 150-400°C, reaction pressure of 0.5-5 MPa, and weight hourly space velocity of the reaction raw materials of 0.1-5 h -1 .

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