A method for preparing a catalyst for the gas-phase alkyl transfer synthesis of ethylbenzene from benzene and polyethylbenzene and its application.

Abstract

The present invention discloses a preparation method and application of a catalyst for preparing ethylbenzene by gas-phase transalkylation of benzene and polyethylbenzenes, the preparation method comprising the following steps: (1) mixing ZSM-11 molecular sieve raw powder with a binder and pressing the tablets, exchanging the molecular sieve mixed with the binder with an ammonium solution, and calcining to obtain H-ZSM-11 molecular sieve; (2) steam treatment at 400-800°C for 1-8h; (3) adding the molecular sieve obtained in step (2) to a metal element impregnation solution, stirring and impregnating at 80-95°C for 4-12h, then standing for 3-5h, and removing the upper liquid; wherein the metal is an alkali metal, an alkaline earth metal, a rare earth metal or Zn; (4) drying and calcining to obtain a catalyst. The catalyst prepared by the present invention has reduced acidity, improved catalytic activity and stability, and high selectivity for ethylbenzene.

Description

Technical Field

[0001] The invention belongs to the technical field of ethylbenzene preparation, and specifically relates to a preparation method and application of a catalyst for preparing ethylbenzene by gas-phase alkylation transfer of benzene and polyethylbenzenes. Background Art

[0002] Ethylbenzene is an important chemical raw material, and its main use is catalytic dehydrogenation to produce styrene. Styrene is an important synthetic material for the production of polystyrene, engineering plastics and styrene-butadiene rubber. In recent years, the market demand and production capacity of styrene have shown a clear upward trend. my country has the world's largest styrene market. It is estimated that my country will have 6.862 million tons of new styrene production capacity during 2018-2022. At present, ethylbenzene is mainly produced in industry by alkylation reaction of benzene and ethylene / ethanol. The main processes are liquid phase alkylation and gas phase alkylation.

[0003] The traditional method for producing ethylbenzene is mainly to produce ethylbenzene through the alkylation reaction of benzene and ethylene or ethanol. The main processes are AlCl3 liquid phase alkylation method and molecular sieve alkylation method.

[0004] The AlCl3 liquid phase alkylation process is simple, has mild operating conditions, and a high ethylene conversion rate, but it has problems such as equipment corrosion, environmental pollution, and high maintenance costs. The selectivity of ethylbenzene in the product can reach more than 95%.

[0005] The molecular sieve alkylation method mainly uses molecular sieve gas phase alkylation to produce ethylbenzene. The alkylation method has the advantages of being non-corrosive, non-polluting, simple in process, and having a high heat recovery rate.

[0006] Patent CN102274746A reports a nano ZSM-5 catalyst that has been modified with rare earth, treated with water vapor and phosphoric acid. n (Benzene) / n (Ethanol) = 6.5, WHSV 乙醇 =0.8h -1 Under the following conditions, the ethanol conversion rate can reach 99.9%, the ethyl selectivity can reach 99.9%, the xylene content in the ethylbenzene product can be below 800ppm, and the catalyst regeneration period can reach half a year.

[0007] Patent CN101450888A reports a rare earth modified ZSM-5 catalyst with a high silicon-aluminum ratio. n (Benzene) / n (Ethanol) = 6, WHSV 乙醇 =2h -1 Under the conditions of , the highest conversion rate of raw benzene was 16.58% and the selectivity of ethylbenzene was 96.76%.

[0008] The gas phase alkylation catalysts reported above are mainly ZSM-5 molecular sieves. In addition, ZSM-11, MCM-22, Beta, Y-type molecular sieves, etc. are also disclosed.

[0009] Patent CN110465326A discloses a process for producing ethylbenzene from benzene and ethanol by vapor phase alkylation using modified ZSM-11 molecular sieve, achieving an ethanol conversion rate of 98% and good ethylbenzene selectivity.

[0010] The alkylation of benzene and ethylene / ethanol to produce ethylbenzene is mainly catalyzed by AlCl3, FeCl3 or a catalyst with Lewis strong acid (such as ZSM-5, ZSM-11, Beta molecular sieve, etc.). Since the alkylation reaction is a reversible reaction, the reaction process will not stop at the primary alkylation stage. The generated ethylbenzene is more active than the raw benzene and will continue to undergo secondary alkylation to produce diethylbenzene, triethylbenzene, etc. In general experiments and industry, excessive benzene is generally added to inhibit the formation of diethylbenzene and triethylbenzene to increase the yield of ethylbenzene, but a high benzene-to-ethanol ratio will increase the operating load of the device. In order to improve the selectivity of ethylbenzene without increasing the operating load of the device, it is necessary to effectively utilize the polyethylbenzenes in the product.

[0011] At present, whether it is a gas phase process or a liquid phase process, the latest catalyst can inhibit the occurrence of side reactions and make the selectivity of ethylbenzene in the product reach more than 99%, but there is still 5~7% diethylbenzene in the product. In industry, polyethylbenzenes (mainly diethylbenzene, a small amount of triethylbenzene) in the alkylation reaction are generally subjected to transalkylation reaction with benzene in an alkylation reactor to continue to generate the target product ethylbenzene.

[0012] Patents CN1096025A, CN1199727A and USP5030786 respectively report methods for producing ethylbenzene by transalkylation of benzene and polyethylbenzenes using Y-type molecular sieves under liquid phase process.

[0013] Patents CN10956025A and USP4891456 reported the process of preparing ethylbenzene from benzene and diethylbenzene at 260°C and 3.5MPa using Beta molecular sieve, and the conversion rate of diethylbenzene reached 57%.

[0014] Patent CN1207960A reports a rare earth modified or alkaline earth metal modified Beta molecular sieve. n (Benzene) / n (Ethylbenzene) = 8~12, WHSV 混合液 =6~10h -1 Under the conditions of , the conversion rate of polyethylbenzene is about 45%.

[0015] Patent CN1597110A reports the use of MCM-22 molecular sieves for the transalkylation process of benzene and diethylbenzene. The modified molecular sieve can achieve a diethylbenzene conversion rate and ethylbenzene selectivity of more than 70% and 99%, respectively.

[0016] The above-reported process of transalkylation of benzene and polyethylbenzenes to produce polyethylbenzenes is a liquid phase process, and the catalysts used are mostly the same as those used in the liquid phase alkylation of benzene to produce ethylbenzene, mostly Y-type, β-type, MWW (MCM-22, MCM-49, etc.). The advantages of the liquid phase process are low operating temperature and low content of by-product diethylbenzene, but the required pressure is relatively high.

[0017] The method that has achieved significant commercialization is to use solid acid catalysts to carry out gas-phase transalkylation of benzene and polyethylbenzenes. U.S. Patents US3751504, US3965364, and US4016218 reported the use of unmodified ZSM-5, phosphorus-modified ZSM-5, and steam-treated ZSM-5 to catalyze the gas-phase transalkylation of benzene and polyethylbenzenes.

[0018] Patent CN1310051A reports a process of catalyzing the reaction of benzene and polyethylbenzenes using a ZSM-5 catalyst treated with water vapor and organic acid. At a reaction temperature of T = 435 ° C, 0.6 MPa, and a weight space velocity of benzene and polyethylbenzenes of 28 h -1 , n Under the condition of (benzene) / n(polyethylbenzene) = 5.0, the polyethylbenzene conversion rate was 60%, the ethylbenzene selectivity was above 96%, and the xylene content in the product was 750ppm.

[0019] Zhao Xuesong et al. [Zhao Xuesong, Liu Shenglin, Chen Fucun et al., Vapor-phase transalkylation of diethylbenzene over ZSM-5 / ZSM-11 co-crystallized molecular sieves, Journal of Natural Science of Heilongjiang University, 2006, 23(3):6] studied the transalkylation performance of 3884A catalyst on a fixed bed at a reaction temperature of 420°C, a pressure of 0.7 MPa, and a weight space velocity of 1 h-1. -1 Under the conditions of n (benzene / polyethylbenzenes) = 5.0, the conversion rate of polyethylbenzenes was 28.43% and the selectivity of ethylbenzene was 95.15%. Summary of the invention

[0020] The invention provides a preparation method of a catalyst for gas-phase transalkylation of benzene and polyethylbenzenes to produce ethylbenzene and its application. When the catalyst is used for gas-phase transalkylation of benzene and polyethylbenzenes to produce ethylbenzene, the conversion rate of polyethylbenzenes is high and the stability is good.

[0021] A method for preparing a catalyst for preparing ethylbenzene by gas-phase transalkylation of benzene and polyethylbenzenes, comprising the following steps:

[0022] (1) ZSM-11 molecular sieve raw powder is mixed with a binder to form tablets, the molecular sieve mixed with the binder is subjected to ammonium exchange treatment with an ammonium solution, and calcined to obtain H-ZSM-11 molecular sieve;

[0023] (2) steam treatment at a treatment temperature of 400-800°C for 1-8h;

[0024] (3) adding the molecular sieve obtained in step (2) into a metal element impregnation solution, stirring and impregnating at 80-95° C. for 4-12 hours, then standing for 3-5 hours, and removing the upper layer of liquid; wherein the metal is an alkali metal, an alkaline earth metal, a rare earth metal or Zn;

[0025] (4) After drying and calcination, the catalyst can be obtained.

[0026] Preferably, the alkali metal is Cs, the alkaline earth metal is Mg, and the rare earth metal is La or Ce.

[0027] Preferably, in step (3), during the impregnation, the ratio of the impregnation liquid to the molecular sieve mixed with the binder is (10-20) mL: 1 g.

[0028] Preferably, the impregnation solution is an aqueous solution of a soluble carbonate, nitrate, chloride or acetate corresponding to the alkali metal or alkaline earth metal; the concentration of the impregnation solution is 0.5-2 mol / L.

[0029] Preferably, in step (1), the total weight of the molecular sieve mixed with the binder is calculated as 100%, the content of the ZSM-11 molecular sieve raw powder is 50-90%, and the balance is the binder. More preferably, the content of the ZSM-11 molecular sieve raw powder is 50-70%.

[0030] Preferably, the ammonium exchange is specifically as follows: mixing the molecular sieve mixed with the binder with the ammonium solution, stirring and reflux at 80-90°C for 5-6h, centrifuging, filtering, and drying; repeating the above operation twice; wherein the mass ratio of the molecular sieve mixed with the binder to the ammonium solution is 1:(20-25); and the ammonium solution is a 1-3 mol / L NH4Cl solution or NH4NO3 solution.

[0031] Preferably, the binder is a mixture of SiO2 and Al2O3.

[0032] Preferably, the silicon-aluminum ratio of the ZSM-11 molecular sieve raw powder is 30-100. More preferably, the silicon-aluminum ratio of the ZSM-11 molecular sieve raw powder is 30-50.

[0033] Preferably, the water vapor treatment is specifically as follows: placing the molecular sieve in a fixed bed reactor, heating it to the treatment temperature under an inert gas atmosphere, turning off the inert gas, and introducing liquid water at a flow rate of 0.05-1 mL / min.

[0034] Preferably, the drying condition is 105-120° C. for 5-8 h, and the calcination condition is 550-650° C. for 5-6 h.

[0035] The catalyst prepared by the preparation method of the present invention is used for preparing ethylbenzene by gas-phase alkylation of benzene and polyethylbenzenes. The specific method is as follows: the catalyst is crushed, sieved through 20-40 mesh, loaded into a fixed bed catalyst, activated at 450-500°C for 4-5h, and nitrogen is used as a carrier gas. Benzene and polyethylbenzenes are used as raw materials and reacted at 400-450°C and 1-2MPa; wherein the molar ratio of benzene to polyethylbenzenes is 6-8:1, and the weight space velocity of the polyethylbenzene mixed liquid is 1-2h -1 ; The polyethylbenzene is diethylbenzene, or a mixture of diethylbenzene and triethylbenzene.

[0036] Advantages of the present invention:

[0037] (1) The preparation method of the present invention can effectively adjust the distribution and acid strength of B acid and L acid on the catalyst by treating the ZSM-11 molecular sieve raw powder with water vapor and metal. After the treatment, the acid strength of the catalyst can be significantly changed, especially the acid strength of the strong acid can be reduced.

[0038] (2) Compared with conventional ZSM-11 molecular sieve, the catalyst prepared by the present invention has reduced acidity, improved catalytic activity and stability, and high selectivity for ethylbenzene. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 is the XRD pattern of the catalyst obtained in Example 1;

[0040] Figure 2 This is a comparison chart of NH3-TPD of different catalysts. DETAILED DESCRIPTION

[0041] Example 1

[0042] A method for preparing a catalyst for preparing ethylbenzene by gas-phase transalkylation of benzene and polyethylbenzenes, comprising the following steps:

[0043] (1) ZSM-11 molecular sieve raw powder with a silicon-aluminum ratio of 50 was mixed with a binder in a mass ratio of 80:20, and tableted to obtain a molecular sieve mixed with a binder. 20 g of the mixture was taken and mixed with a 1 mol / L NH4Cl solution in a mass ratio of 1:25, stirred and refluxed at 90°C for 6 h, centrifuged, filtered, and dried at 105°C for 6 h; the above-mentioned mixing with NH4Cl solution, stirring, centrifuging, filtering, and drying were repeated twice; then the mixture was calcined at 550°C for 6 h to obtain an H-ZSM-11 molecular sieve; the binder was a mixture of SiO2 and Al2O3 in an equal mass ratio;

[0044] (2) placing the molecular sieve obtained in step (1) in a fixed bed reactor, heating to 500°C under a nitrogen atmosphere, turning off the inert gas, introducing liquid water at a flow rate of 1 mL / min, and treating with water vapor at 500°C for 5 h;

[0045] (3) Add the molecular sieve obtained in step (2) into 200 mL of 1 mol / L Mg(CH3COO)2 aqueous solution, stir and immerse for 10 h at 85 °C and 300 rpm, then let it stand for 3 h and remove the upper liquid;

[0046] (4) After drying at 105 °C for 8 h and calcining at 550 °C for 6 h, the catalyst was obtained and labeled as Cat-1.

[0047] Example 2

[0048] A method for preparing a catalyst for preparing ethylbenzene by gas-phase transalkylation of benzene and polyethylbenzenes, comprising the following steps:

[0049] (1) ZSM-11 molecular sieve raw powder with a silicon-aluminum ratio of 50 was mixed with a binder in a mass ratio of 80:20, and tableted to obtain a molecular sieve mixed with a binder. 20 g of the mixture was taken and mixed with a 1 mol / L NH4Cl solution in a mass ratio of 1:20, stirred and refluxed at 90°C for 6 h, centrifuged, filtered, and dried at 105°C for 6 h; the above-mentioned mixing with NH4Cl solution, stirring, centrifuging, filtering, and drying were repeated twice; and then calcined at 550°C for 6 h to obtain an H-ZSM-11 molecular sieve; the binder was a mixture of SiO2 and Al2O3 in an equal mass ratio;

[0050] (2) placing the molecular sieve obtained in step (1) in a fixed bed reactor, heating to 550°C under a nitrogen atmosphere, turning off the inert gas, introducing liquid water at a flow rate of 1 mL / min, and treating with water vapor at 550°C for 5 h;

[0051] (3) Add the molecular sieve obtained in step (2) into 400 mL of 1 mol / L Zn(NO3)2·6H2O solution, stir and immerse for 10 h at 85°C and 400 rpm, then let it stand for 5 h and remove the upper liquid;

[0052] (4) After drying at 120 °C for 5 h and calcining at 650 °C for 5 h, the catalyst was obtained and labeled as Cat-2.

[0053] Example 3

[0054] A method for preparing a catalyst for preparing ethylbenzene by gas-phase transalkylation of benzene and polyethylbenzenes, comprising the following steps:

[0055] (1) ZSM-11 molecular sieve raw powder with a silicon-aluminum ratio of 50 was mixed with a binder in a mass ratio of 80:20, and tableted to obtain a molecular sieve mixed with a binder. 20 g of the mixture was taken and mixed with a 1 mol / L NH4Cl solution in a mass ratio of 1:25, stirred and refluxed at 90°C for 6 h, centrifuged, filtered, and dried at 105°C for 6 h; the above-mentioned mixing with NH4Cl solution, stirring, centrifuging, filtering, and drying were repeated twice; then the mixture was calcined at 550°C for 6 h to obtain an H-ZSM-11 molecular sieve; the binder was a mixture of SiO2 and Al2O3 in an equal mass ratio;

[0056] (2) placing the molecular sieve obtained in step (1) in a fixed bed reactor, heating to 550°C under a nitrogen atmosphere, turning off the inert gas, introducing liquid water at a flow rate of 1 mL / min, and treating with water vapor at 550°C for 5 h;

[0057] (3) Add the molecular sieve obtained in step (2) into 200 mL of 2 mol / L Mg(CH3COO)2 solution, stir and immerse for 10 h at 85 °C and 250 rpm, then let it stand for 3 h and remove the upper liquid;

[0058] (4) After drying at 120 °C for 5 h and calcining at 650 °C for 5 h, the catalyst was obtained and labeled as Cat-3.

[0059] Example 4

[0060] A method for preparing a catalyst for preparing ethylbenzene by gas-phase transalkylation of benzene and polyethylbenzenes, comprising the following steps:

[0061] (1) Mix ZSM-11 molecular sieve powder with a silicon-aluminum ratio of 30 with a binder in a mass ratio of 50:50, press into tablets to obtain a molecular sieve mixed with a binder, take 20g, mix it with 3mol / L NH4NO3 solution in a mass ratio of 1:25, stir and reflux at 80℃ for 5h, centrifuge, filter, and dry at 120℃ for 5h; repeat the above operation of mixing with NH4NO3 solution, stirring, centrifuging, filtering, and drying twice; then calcine at 650℃ for 5h to obtain H-ZSM-11 molecular sieve; the binder is a mixture of SiO2 and Al2O3 in equal mass ratios;

[0062] (2) placing the molecular sieve obtained in step (1) in a fixed bed reactor, heating to 400°C under a nitrogen atmosphere, turning off the inert gas, introducing liquid water at a flow rate of 1 mL / min, and treating with water vapor at 400°C for 8 h;

[0063] (3) Add the molecular sieve obtained in step (2) into 200 mL of 0.5 mol / L La(NO3)3·6H2O solution, stir and immerse for 12 h at 80°C and 1000 rpm, then let it stand for 3 h and remove the upper liquid;

[0064] (4) After drying at 120 °C for 5 h and calcining at 650 °C for 5 h, the catalyst was obtained and labeled as Cat-4.

[0065] Example 5

[0066] A method for preparing a catalyst for preparing ethylbenzene by gas-phase transalkylation of benzene and polyethylbenzenes, comprising the following steps:

[0067] (1) ZSM-11 molecular sieve raw powder with a silicon-aluminum ratio of 100 was mixed with a binder in a mass ratio of 90:10, and tableted to obtain a molecular sieve mixed with a binder. 20 g of the mixture was mixed with a 3 mol / L NH4NO3 solution in a mass ratio of 1:25, stirred and refluxed at 80°C for 5 h, centrifuged, filtered, and dried at 105°C for 8 h; the above-mentioned mixing with NH4NO3 solution, stirring, centrifuging, filtering, and drying were repeated twice; and then calcined at 650°C for 5 h to obtain an H-ZSM-11 molecular sieve; the binder was a mixture of SiO2 and Al2O3 in an equal mass ratio;

[0068] (2) placing the molecular sieve obtained in step (1) in a fixed bed reactor, heating to 800°C under a nitrogen atmosphere, turning off the inert gas, introducing liquid water at a flow rate of 0.05 mL / min, and treating with water vapor at 800°C for 1 h;

[0069] (3) Add 200 mL of 0.5 mol / L of the molecular sieve obtained in step (2) CsClThe solution was stirred and immersed at 95 °C and 200 rpm for 4 h, then allowed to stand for 3 h and the upper liquid was removed;

[0070] (4) After drying at 105 °C for 8 h and calcining at 650 °C for 5 h, the catalyst was obtained and labeled as Cat-5.

[0071] Comparative Example 1

[0072] The molecular sieve obtained in step (1) of Example 1.

[0073] Comparative Example 2

[0074] The ZSM-5 molecular sieve raw powder with the same silicon-aluminum ratio was used to replace the ZSM-11 molecular sieve raw powder, and the other steps were the same as in Example 1.

[0075] 1. Acidity distribution

[0076] The acid amount distribution of the molecular sieve catalyst obtained in Example 1 and Comparative Example 1 was detected, and the results are shown in Table 1. The acid amount of B acid and L acid of the molecular sieve was obtained by the pyridine desorption amount measured after desorption at 200°C and 350°C, wherein the total acid amount at 200°C corresponds to the total acid amount of the catalyst, and the total acid amount at 350°C corresponds to the acid amount of the strong acid and medium-strong acid of the catalyst.

[0077] Table 1 Acid content distribution

[0078]

[0079] As shown in Table 1, the distribution of B acid and L acid on the catalyst and the acid strength can be effectively adjusted after the catalyst is treated with water vapor and then loaded with oxide MgO. Although the total acid content on the modified catalyst does not change much, the B acid on the modified catalyst increases significantly.

[0080] 2. XRD detection

[0081] The catalyst obtained in Example 1 was subjected to XRD testing, and the results are shown in Figure 1 .

[0082] Depend on Figure 1 It can be seen that the diffraction peak of ZSM-11 at 2θ of 45.20° is a single peak; there are two characteristic peaks at 22.5°~25.5°, which are respectively attributed to the characteristic diffraction peaks of the (501) and (303) crystal planes of the ZSM-11 molecular sieve, indicating that the synthesized molecular sieve is a typical MEL configuration molecular sieve. In addition, it can be seen that after water vapor treatment and MgO loading, the position and intensity of the characteristic diffraction peaks of ZSM-11 have not changed, indicating that the molecular sieve modified by MgO still maintains the framework structure of ZSM-11.

[0083] 3. NH3-TPD detection

[0084] The catalysts of Examples 1-3 and Comparative Example 1 were tested by NH3-TPD. Figure 2 .

[0085] Depend on Figure 2 It can be seen that compared with the untreated ZSM-11, the catalyst provided by the present invention has a smaller weak acid peak intensity and a significantly weaker strong acid peak.

[0086] 4. Catalyst performance testing

[0087] The catalyst prepared by the preparation method of the present invention is used for preparing ethylbenzene by gas-phase alkylation of benzene and polyethylbenzenes. The specific method is as follows: the catalyst is crushed, sieved through 20-40 mesh, loaded into a fixed bed catalyst, activated at 500°C for 5h, and nitrogen is used as a carrier gas. Benzene and polyethylbenzenes are used as raw materials and reacted at 420°C and 1MPa; wherein the molar ratio of benzene to polyethylbenzenes is 6:1, and the weight space velocity of the polyethylbenzene mixed liquid is 1h -1 ; The polyethylbenzene is diethylbenzene, or a mixture of diethylbenzene and triethylbenzene;

[0088] The specific reaction conditions and results are shown in Table 2.

[0089] Table 2 Reaction conditions and results

[0090]

[0091] As shown in Table 2, the direct use of unmodified ZMS-11 as a catalyst for the gas-phase transalkylation of benzene and polyethylbenzenes to produce ethylbenzene in Comparative Example 1 has three disadvantages: low conversion rate of polyethylbenzenes, high content of xylene in byproducts, resulting in relatively low selectivity of the main product ethylbenzene. The modified ZSM-11 catalyst provided by the present invention can achieve higher raw material conversion and high selectivity and purity of product ethylbenzene. While the ZSM-5 molecular sieve is used in Comparative Example 2, although the ZSM-5 molecular sieve is also a two-dimensional pore system, its elliptical pore structure is longer than the two-dimensional straight pores of the ZSM-11 molecular sieve, and the generated C7~C10 aromatics are not easy to desorb, and more side reactions are likely to occur, so the aromatics selectivity is lower than that of ZSM-11, and the use of ZSM-5 for substitution cannot meet the purpose of the present invention.

Claims

1. A method for preparing a catalyst for gas phase transalkylation of benzene and polyethylbenzenes to produce ethylbenzene, characterized in that: The following steps are involved: (1) Mixing ZSM-11 molecular sieve raw powder with a binder to form tablets, exchanging the obtained molecular sieve mixed with the binder with an ammonium solution, and calcining to obtain H-ZSM-11 molecular sieve; (2) steam treatment at a treatment temperature of 400-800°C for 1-8h; (3) adding the molecular sieve obtained in step (2) into a metal element impregnation solution, stirring and impregnating at 80-95° C. for 4-12 hours, then standing for 3-5 hours, and removing the upper layer of liquid; wherein the metal is an alkali metal, an alkaline earth metal, a rare earth metal or Zn; (4) After drying and calcination, the catalyst can be obtained.

2. The method for preparing a catalyst for preparing ethylbenzene by gas phase transalkylation of benzene and polyethylbenzenes according to claim 1, wherein: In step (3), during the impregnation, the ratio of the impregnation liquid to the molecular sieve mixed with the binder is (10-20) mL: 1 g.

3. The method for preparing a catalyst for preparing ethylbenzene by gas phase transalkylation of benzene and polyethylbenzenes according to claim 2, wherein: The impregnation solution is an aqueous solution of soluble carbonate, nitrate, chloride or acetate corresponding to the metal; the concentration of the impregnation solution is 0.5-2 mol / L.

4. The method for preparing a catalyst for preparing ethylbenzene by gas phase transalkylation of benzene and polyethylbenzenes according to claim 3, characterized in that: In step (1), the total weight of the molecular sieve mixed with the binder is calculated as 100%, the content of the ZSM-11 molecular sieve raw powder is 50-90%, and the remainder is the binder.

5. The method for preparing a catalyst for preparing ethylbenzene by gas phase transalkylation of benzene and polyethylbenzenes according to claim 4, characterized in that: The ammonium exchange is specifically as follows: mixing the molecular sieve mixed with the binder with the ammonium solution, stirring and refluxing at 80-90°C for 5-6h, centrifuging, filtering, and drying; repeating the above operation twice; wherein the mass ratio of the molecular sieve mixed with the binder to the ammonium solution is 1:(20-25); and the ammonium solution is a 1-3 mol / L NH4Cl solution or NH4NO3 solution.

6. The method for preparing a catalyst for preparing ethylbenzene by gas phase transalkylation of benzene and polyethylbenzenes according to claim 5, characterized in that: The binder is a mixture of SiO2 and Al2O3.

7. The method for preparing a catalyst for preparing ethylbenzene by gas phase transalkylation of benzene and polyethylbenzenes according to claim 6, characterized in that: The silicon-aluminum ratio of the ZSM-11 molecular sieve raw powder is 30-100.

8. The method for preparing a catalyst for preparing ethylbenzene by gas phase transalkylation of benzene and polyethylbenzenes according to claim 7, characterized in that: The water vapor treatment is specifically as follows: placing the molecular sieve in a fixed bed reactor, heating it to the treatment temperature under an inert gas atmosphere, turning off the inert gas, and introducing liquid water at a flow rate of 0.05-1 mL / min.

9. The method for preparing a catalyst for preparing ethylbenzene by gas phase transalkylation of benzene and polyethylbenzenes according to claim 8, characterized in that: The drying condition is drying at 105-120° C. for 5-8 hours, and the calcination condition is calcining at 550-650° C. for 5-6 hours.

10. A method for preparing ethylbenzene by gas phase transalkylation of benzene and polyethylbenzenes, characterized in that: The catalyst is crushed, sieved through 20-40 mesh, loaded into a fixed bed catalyst, activated at 450-500°C for 4-5h, and then reacted at 400-450°C and 1-2MPa with nitrogen as carrier gas and benzene and polyethylbenzene as raw materials; wherein the molar ratio of benzene to polyethylbenzene is 6-8:1, and the weight space velocity of the polyethylbenzene mixed liquid is 1-2h -1 ; The polyethylbenzene is diethylbenzene, or a mixture of diethylbenzene and triethylbenzene; the catalyst is a catalyst prepared by the preparation method according to any one of claims 1-9.

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