A method for preparing a metal ion-doped defect-type FER molecular sieve

Abstract

This invention relates to the fields of materials science and chemistry, and discloses a method for preparing a metal ion-doped defective FER molecular sieve. The method includes a molecular sieve using Cu and Co as doping ions, with a basic framework of a defective FER molecular sieve having a silicon-to-aluminum ratio of 30-40. The molecular sieve is based on the mass of the defective FER molecular sieve, and the mass percentage of the doping ions is 3-5%. This invention employs a two-step synthesis method. The first step involves hydrothermal crystallization to synthesize a pre-crystallized FER molecular sieve. The second step increases the hydrothermal crystallization temperature, causing the unstable molecular sieve structure to transform into a high silicon-to-aluminum ratio defective crystal form under high temperature and pressure, while simultaneously introducing heteroions into the molecular sieve framework. Compared to traditional techniques, this method can achieve a larger doping amount and is simpler with readily available raw materials. Its application in the catalytic synthesis of ethylene glycol dimethyl ether from ethylene glycol and methanol can achieve high conversion rates and high selectivity, demonstrating significant economic value and market potential.

Description

Technical Field

[0001] This invention relates to the fields of materials science and chemistry, and in particular to a method for preparing a metal ion-doped defect-type FER molecular sieve. Background Technology

[0002] Dimethyl ethylene glycol ether (DMET) possesses stable chemical properties and excellent solubility, making it a widely used solvent. It is also used as a pharmaceutical extractant and organic intermediate. Furthermore, it can be used as a coating solvent, an antifreeze additive, and in various fields such as the cosmetics, fragrance, pharmaceutical, and oilfield industries. In recent years, the applications of DMET have continued to expand, finding extensive use in electrochemistry, organic compounds, cleaning agent formulations, and adhesive formulations. With the increasing demand, developing cost-effective and efficient synthesis processes is of great significance.

[0003] Among existing technologies, the synthesis of DMET using ethylene glycol and methanol as raw materials is considered the most economical and environmentally friendly. Furthermore, with the successful industrialization of coal-to-ethylene glycol processes, the source of ethylene glycol is secured. However, this reaction involves numerous side reactions, necessitating the development of catalysts with high activity and selectivity to improve the yield of DMET. US Patent US2004 / 0044253 reports a method for synthesizing DMET from ethylene glycol and lower alcohols using perfluorosulfonic acid resin catalysis, achieving a selectivity of up to 94.3%. However, this catalyst is expensive, and the synthesis process is complex, making it difficult to meet industrial production needs. Patent CN112979428B discloses a tandem method for preparing ethylene glycol dimethyl ether, utilizing a superacid catalyst and molecular sieves to first catalyze the synthesis of intermediate products, and then using molecular sieves and ion exchange resins to catalyze the synthesis of DMET, achieving a selectivity of approximately 90%. However, this method's unique process design places high demands on equipment, resulting in significant equipment costs. The key to the synthesis process lies in the catalyst; therefore, the development of a low-cost, high-conversion catalyst is urgently needed.

[0004] The key to catalyzing the reaction of ethylene glycol and methanol lies in the surface acidity of the catalyst. Molecular sieves are aluminosilicate crystals with a regular, ordered three-dimensional porous structure. The hydroxyl groups on their surface and the Al ions outside the framework enrich the surface with weak Brønsted (B) and Lewis (L) acid sites. The Si-(OH)-Al bridging bonds in the framework provide strong B acid sites, and the Al elements at defect sites provide strong Lewis acid sites. Therefore, molecular sieves are widely used in the petrochemical industry. FER molecular sieves are mesoporous zeolite molecular sieves composed of six-, eight-, and ten-membered rings. They are structurally stable and widely used in addition reactions. However, single FER molecular sieves exhibit limited activity and are prone to carbon deposition in the catalytic synthesis of DMET from methanol and ethylene glycol, necessitating modification. Heteroatom doping is a common molecular sieve modification technique. By introducing heteroatoms to isomorphically replace Si / Al atoms in the framework, it modulates the acidity, pore size, and catalytic performance of the molecular sieve, significantly enhancing its catalytic activity. For example, patent CN106315609B discloses a one-step method for preparing a rare-earth complex framework-doped microporous-mesoporous composite molecular sieve. This method involves uniformly mixing rare-earth element nitrates with SBA-15 molecular sieves, followed by calcination to successfully introduce the rare-earth elements into the framework structure. However, under high-temperature conditions, the molecular sieve structure is unstable and prone to framework collapse. Patent CN113277530A discloses a niobium-doped AlPO-31 molecular sieve crystal and its preparation method. This method involves uniformly mixing niobium oxalate with the molecular sieve raw material and performing elemental niobium doping via a simultaneous hydrothermal method. This method ensures uniform distribution of the doping element, but the presence of impurities during hydrothermal crystallization can damage the molecular sieve structure. Excessive impurities can prevent the molecular sieve framework from forming, therefore only a very small amount of impurities can be introduced. Based on this, developing a FER molecular sieve with high conversion rate and high selectivity is of great significance. Summary of the Invention

[0005] The purpose of this invention is to address the shortcomings of existing technologies by proposing a method for preparing metal ion-doped defect-type FER molecular sieves.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A method for preparing a metal ion-doped defective FER molecular sieve includes a molecular sieve using Cu and Co as doping ions, wherein the molecular sieve uses a defective FER molecular sieve with a silicon-to-aluminum ratio of 30-40 as the basic framework, and the molecular sieve is based on the mass of the defective FER molecular sieve, with the mass percentage of doping ions being 3%-5%.

[0008] Includes the following steps:

[0009] S1: Dissolve the silicon source, aluminum source, template agent and crystallization aid in deionized water and stir evenly. Adjust the pH value to 10 using a pH adjuster.

[0010] S2: Transfer the mixed solution to the reactor and perform dynamic hydrothermal crystallization at 130~150℃ for 72~96h for the first time; after cooling, open the reactor and add the heteroion compound, and perform dynamic hydrothermal crystallization at 200~220℃ for 3~5h for the second time. Then, obtain the metal ion doped defect type FER molecular sieve by washing, filtration and drying.

[0011] S3: Disperse the metal ion-doped defective FER molecular sieve powder obtained in step S2 in ammonium chloride solution, stir for 2-4 hours, wash, filter and dry, and finally transfer to a muffle furnace for calcination to obtain the final product.

[0012] As a further embodiment of the present invention, the silicon source is any one of tetraethyl orthosilicate, sodium silicate, and silica sol; the aluminum source is any one of aluminum nitrate, aluminum chloride, and aluminum sulfate; the template agent is any one of pyridine, morpholine (CTAB), and ethylenediamine; the crystallization aid is any one of sodium sulfate and sodium chloride; and the pH adjuster is any one of H2SO4, HCl, and NaOH.

[0013] As a further embodiment of the present invention, the molar ratio of silicon source, aluminum source, template agent, crystallization aid and water in S1 is (30~40):1:(15~20):(5~10):(700~900).

[0014] As a further embodiment of the present invention, the pH value of S1 is adjusted to 10 by using any one of H2SO4, HCl and NaOH.

[0015] As a further embodiment of the present invention, the first dynamic hydrothermal crystallization temperature in S2 is 130~150℃ and the crystallization time is 72~96h, and the second dynamic hydrothermal crystallization temperature in S2 is 200~220℃ and the crystallization time is 3~5h.

[0016] As a further embodiment of the present invention, the heteroionic compound in S2 is either a sulfate or a chloride of Cu and Co, and the amount of heteroionic compound added in S2 is 3% to 5% of the mass of the defective FER molecular sieve.

[0017] As a further embodiment of the present invention, the concentration of the ammonium chloride solution in S3 is 1~2M, the mass ratio of the ammonium chloride solution to the metal ion doped defect type FER molecular sieve is 10~15:1, the stirring time is 2~4h and the stirring temperature is 50~80℃.

[0018] As a further embodiment of the present invention, the calcination environment in S3 is an empty atmosphere and the calcination temperature is 500~550℃, and the calcination time is 2~4h.

[0019] As a general inventive concept, this invention provides an application of the metal ion-doped defective FER molecular sieve prepared by the above-described preparation method in the catalytic synthesis of ethylene glycol dimethyl ether from ethylene glycol and methanol.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] This invention discloses a method for preparing and applying a metal ion-doped defective FER molecular sieve. The molecular sieve is synthesized via a two-step process: the first step involves hydrothermal crystallization to synthesize a pre-crystallized FER molecular sieve; the second step involves increasing the hydrothermal crystallization temperature, causing the unstable molecular sieve structure to transform into a high-silicon-to-aluminum ratio defective crystal form under high temperature and pressure, while simultaneously introducing heteroions into the molecular sieve framework. Compared to traditional techniques, this method can achieve a larger doping amount and is simpler with readily available raw materials. Its application in the catalytic synthesis of ethylene glycol dimethyl ether from ethylene glycol and methanol achieves high conversion rates and high selectivity, demonstrating significant economic value and promising market prospects. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the ethylene glycol (EG) conversion rate in the preparation method of the metal ion doped defect-type FER molecular sieve proposed in this invention.

[0023] Figure 2 This is a schematic diagram of the selectivity of ethylene glycol dimethyl ether (DMET) in the preparation method of the metal ion doped defective FER molecular sieve proposed in this invention. Detailed Implementation

[0024] To facilitate understanding of the present invention, the present invention will be described more fully and in detail below with reference to the accompanying drawings and preferred embodiments, but the scope of protection of the present invention is not limited to the following specific embodiments.

[0025] Unless otherwise defined, all technical terms used herein have the same meaning as commonly understood by those skilled in the art. The technical terms used herein are for the purpose of describing particular embodiments only and are not intended to limit the scope of the invention.

[0026] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this invention can be purchased from the market or prepared by existing methods.

[0027] Performance evaluation method: The catalyst performance was evaluated using a fixed-bed microreactor with an inner diameter of 10 mm and a length of 550 mm. The bottom layer was filled with quartz sand for support, and then separated by quartz wool. 2 g of molecular sieve powder was mixed evenly with 2 g of quartz sand and transferred to the reaction tube, ensuring it was in the center. Quartz wool was placed above it for separation, and then quartz sand was added above that for rectification. Nitrogen gas was used as both a protective gas and a carrier gas at a rate of 10 ml / min, maintaining a pressure of 1 MPa. The reaction tube was preheated to 150 °C. Then, methanol and ethylene glycol were mixed evenly at a mass ratio of 4:1 and pumped into the reactor at a rate of 2 ml / min. Samples were taken for gas chromatography analysis after holding at 160 °C, 170 °C, 180 °C, 190 °C, and 200 °C for 120 min at each temperature.

[0028] Reference Figure 1 - Figure 2 A method for preparing a metal ion-doped defective FER molecular sieve includes a molecular sieve with Cu and Co as doping ions, wherein the molecular sieve is based on a defective FER molecular sieve with a silicon-to-aluminum ratio of 30-40, and the molecular sieve is based on the mass of the defective FER molecular sieve, with the mass percentage of doping ions being 3%-5%.

[0029] Includes the following steps:

[0030] S1: Dissolve the silicon source, aluminum source, template agent and crystallization aid in deionized water and stir evenly. Adjust the pH value to 10 using a pH adjuster.

[0031] S2: Transfer the mixed solution to the reactor and perform dynamic hydrothermal crystallization at 130~150℃ for 72~96h for the first time; after cooling, open the reactor and add the heteroion compound, and perform dynamic hydrothermal crystallization at 200~220℃ for 3~5h for the second time. Then, obtain the metal ion doped defect type FER molecular sieve by washing, filtration and drying.

[0032] S3: Disperse the metal ion-doped defective FER molecular sieve powder obtained in step S2 in ammonium chloride solution, stir for 2-4 hours, wash, filter and dry, and finally transfer to a muffle furnace for calcination to obtain the final product.

[0033] Example 1:

[0034] Weigh 100.78g of sodium silicate (SiO2 content 34.78%, Na2O content 17.08%, provided by Guangzhou Hongcheng Chemical Co., Ltd.), 6.48g of Al2(SO4)3·18H2O, 23.07g of pyridine, and 13.81g of anhydrous sodium sulfate and dissolve them in 196.51g of deionized water. Adjust the pH to 10 using sulfuric acid, stir for 30 min, and then transfer to a hydrothermal reactor for crystallization at 150℃ for 96 h. After cooling to room temperature, open the reactor, add 4.11g of CoSO4·7H2O, and continue crystallization at 200℃ for 3 h. After cooling to room temperature, open the reactor, filter, wash, and dry to obtain 29.6g of sodium-type Co ion-doped defective FER molecular sieve. Prepare 296ml of 1M ammonium chloride solution, disperse the molecular sieve powder in the solution, and stir at 80℃ for 4 h. After filtration, washing, and drying, transfer to a muffle furnace and calcine at 500℃ for 3 h to obtain the final product.

[0035] Example 2:

[0036] 162.05 g of tetraethyl orthosilicate, 7.30 g of Al(NO3)3·9H2O, 21.04 g of ethylenediamine, and 9.09 g of sodium chloride were weighed and dissolved in 280.04 g of deionized water. The pH was adjusted to 10 using sulfuric acid, and after stirring for 30 min, the mixture was transferred to a hydrothermal reactor and crystallized at 130 °C for 80 h. After cooling to room temperature, 4.29 g of CuSO4·5H2O was added, and the crystallization reaction continued at 220 °C for 4 h. After cooling to room temperature, the mixture was filtered, washed, and dried to obtain 28.4 g of sodium-type Cu ion-doped defective FER molecular sieve. 426 ml of a 1.5 M ammonium chloride solution was prepared, and the molecular sieve powder was dispersed in the solution and stirred at 60 °C for 3 h. After filtration, washing, and drying, the mixture was transferred to a muffle furnace and calcined at 520 °C for 4 h to obtain the final product.

[0037] Example 3:

[0038] 136.31g of silica sol (30% SiO2 content, provided by Guangzhou Yangmei Chemical Co., Ltd.), 2.59g of AlCl3, 25.41g of morpholine, and 6.82g of sodium chloride were weighed and dissolved in 184.65g of deionized water. The pH was adjusted to 10 using sodium hydroxide, and after stirring for 30 min, the mixture was transferred to a hydrothermal reactor and crystallized at 140℃ for 72 h. After cooling to room temperature, 3.85g of CuCl2·2H2O was added, and the crystallization reaction continued at 220℃ for 5 h. After cooling to room temperature, the mixture was filtered, washed, and dried to obtain 30.1g of sodium-type Cu ion-doped defect-type FER molecular sieve. 301ml of 2M ammonium chloride solution was prepared, and the molecular sieve powder was dispersed in the solution and stirred at 50℃ for 2 h. After filtration, washing, and drying, the mixture was transferred to a muffle furnace and calcined at 550℃ for 2 h to obtain the final product.

[0039] Example 4:

[0040] Weigh 153.27g of sodium silicate (SiO2 content 26.68%, Na2O content 8.35%, provided by Guangzhou Hongcheng Chemical Co., Ltd.), 7.30g of Al(NO3)3·9H2O, 23.38g of ethylenediamine, and 11.36g of sodium chloride and dissolve them in 145.45g of deionized water. Adjust the pH to 10 using hydrochloric acid, stir for 30 min, and then transfer to a hydrothermal reactor for crystallization at 150℃ for 84 h. After cooling to room temperature, open the reactor, add 3.36g of CoCl2·6H2O, and continue crystallization at 200℃ for 4 h. After cooling to room temperature, open the reactor, filter, wash, and dry to obtain 28.6g of sodium-type Co ion-doped defective FER molecular sieve. Prepare 343ml of 1.8M ammonium chloride solution, disperse the molecular sieve powder in the solution, and stir at 60℃ for 2 h. After filtration, washing, and drying, transfer to a muffle furnace and calcine at 500℃ for 4 h to obtain the final product.

[0041] Example 5:

[0042] 141.80 g of tetraethyl orthosilicate, 7.30 g of Al(NO3)3·9H2O, 33.88 g of morpholine, and 9.09 g of sodium chloride were weighed and dissolved in 315.04 g of deionized water. The pH was adjusted to 10 using sodium hydroxide, and after stirring for 30 min, the mixture was transferred to a hydrothermal reactor and crystallized at 150 °C for 96 h. After cooling to room temperature, the reactor was opened, and 2.70 g of CoSO4·7H2O and 2.26 g of CuCl2·2H2O were added. The crystallization reaction was continued at 210 °C for 4 h. After cooling to room temperature, the reactor was opened, filtered, washed, and dried to obtain 28.9 g of sodium-type Co / Cu ion-doped defective FER molecular sieve. 289 ml of 1.2 M ammonium chloride solution was prepared, and the molecular sieve powder was dispersed in the solution and stirred at 80 °C for 4 h. After filtration, washing, and drying, the mixture was transferred to a muffle furnace and calcined at 520 °C for 4 h to obtain the final product.

[0043] Example 6:

[0044] Weigh 134.33 g of sodium silicate (SiO2 content 34.78%, Na2O content 17.08%, provided by Guangzhou Hongcheng Chemical Co., Ltd.), 2.59 g of AlCl3, 27.69 g of pyridine, and 24.86 g of anhydrous sodium sulfate and dissolve them in 197.87 g of deionized water. Adjust the pH to 10 using sulfuric acid, stir for 30 min, and then transfer to a hydrothermal reactor. Crystallize at 130 °C for 90 h. After cooling to room temperature, open the reactor, add 2.77 g of CoSO4·7H2O and 2.28 g of CuSO4·5H2O, and continue crystallizing at 200 °C for 5 h. After cooling to room temperature, open the reactor, filter, wash, and dry to obtain 29.6 g of sodium-type Co / Cu ion-doped defective FER molecular sieve. Prepare 414 ml of 1.5 M ammonium chloride solution, disperse the molecular sieve powder in the solution, and stir at 70 °C for 3 h. After filtration, washing, and drying, the product is transferred to a muffle furnace and calcined at 550°C for 2 hours to obtain the final product.

[0045] Example 7:

[0046] Weigh 87.63g of silica sol (SiO2 content 40%, provided by Guangzhou Yangmei Chemical Co., Ltd.), 6.48g of Al2(SO4)3·18H2O, 17.53g of ethylenediamine, and 11.36g of sodium chloride, and dissolve them in 244.98g of deionized water. Adjust the pH to 10 using hydrochloric acid, stir for 30 min, and then transfer to a hydrothermal reactor. Crystallize at 140℃ for 75 h. After cooling to room temperature, open the reactor, add 1.16g of CoCl2·6H2O and 1.53g of CuCl2·2H2O, and continue crystallizing at 200℃ for 3 h. After cooling to room temperature, open the reactor, filter, wash, and dry to obtain 29.1g of sodium-type Co / Cu ion-doped defective FER molecular sieve. Prepare 437ml of 1M ammonium chloride solution, disperse the molecular sieve powder in the solution, and stir at 60℃ for 4 h. After filtration, washing, and drying, the product is transferred to a muffle furnace and calcined at 520°C for 3 hours to obtain the final product.

[0047] Example 8:

[0048] Weigh 93.47g of silica sol (50% SiO2 content, provided by Guangzhou Yangmei Chemical Co., Ltd.), 6.48g of Al2(SO4)3·18H2O, 30.77g of pyridine, and 13.81g of anhydrous sodium sulfate, and dissolve them in 268.32g of deionized water. Adjust the pH to 10 using sodium hydroxide, stir for 30 min, and then transfer to a hydrothermal reactor. Crystallize at 130℃ for 85 h. After cooling to room temperature, open the reactor, add 4.58g of CoCl2·6H2O and 1.15g of CuSO4·5H2O, and continue crystallizing at 220℃ for 3 h. After cooling to room temperature, open the reactor, filter, wash, and dry to obtain 29.5g of sodium-type Co / Cu ion-doped defective FER molecular sieve. Prepare 295ml of 2M ammonium chloride solution, disperse the molecular sieve powder in the solution, and stir at 50℃ for 2 h. After filtration, washing, and drying, the product is transferred to a muffle furnace and calcined at 520°C for 2 hours to obtain the final product.

[0049] Comparative Example 1:

[0050] Weigh 100.78g of sodium silicate (SiO2 content 34.78%, Na2O content 17.08%, provided by Guangzhou Hongcheng Chemical Co., Ltd.), 6.48g of Al2(SO4)3·18H2O, 23.07g of pyridine, and 13.81g of anhydrous sodium sulfate, and dissolve them in 196.51g of deionized water. Adjust the pH to 10 using sulfuric acid, stir for 30 min, and then transfer to a hydrothermal reactor for crystallization at 150℃ for 96 h. After cooling to room temperature, open the reactor, filter, wash, and dry to obtain 33.6g of sodium-type FER molecular sieve. Prepare 296ml of 1M ammonium chloride solution, disperse the molecular sieve powder in the solution, and stir at 80℃ for 4 h. After filtration, washing, and drying, transfer to a muffle furnace and calcine at 500℃ for 3 h to obtain the final product.

[0051] Comparative Example 2:

[0052] Weigh 153.27g of sodium silicate (SiO2 content 26.68%, Na2O content 8.35%, provided by Guangzhou Hongcheng Chemical Co., Ltd.), 7.30g of Al(NO3)3·9H2O, 23.38g of ethylenediamine, and 11.36g of sodium chloride and dissolve them in 145.45g of deionized water. Adjust the pH to 10 using hydrochloric acid, stir for 30 min, and then transfer to a hydrothermal reactor for crystallization at 150℃ for 84 h. After cooling to room temperature, open the reactor, add 4.32g of CoCl2·6H2O, and continue crystallization at 200℃ for 4 h. After cooling to room temperature, open the reactor, filter, wash, and dry to obtain 27.8g of sodium-type Co ion-doped defective FER molecular sieve. Prepare 343ml of 1.8M ammonium chloride solution, disperse the molecular sieve powder in the solution, and stir at 60℃ for 2 h. After filtration, washing, and drying, transfer to a muffle furnace and calcine at 500℃ for 4 h to obtain the final product.

[0053] Comparative Example 3:

[0054] Weigh 100.78g of sodium silicate (SiO2 content 34.78%, Na2O content 17.08%, provided by Guangzhou Hongcheng Chemical Co., Ltd.), 6.48g of Al2(SO4)3·18H2O, 23.07g of pyridine, and 13.81g of anhydrous sodium sulfate and dissolve them in 196.51g of deionized water. Adjust the pH to 10 using sulfuric acid, stir for 30 min, and then transfer to a hydrothermal reactor for crystallization at 150℃ for 96 h. After cooling to room temperature, open the reactor, filter, wash, and dry to obtain 32.8g of sodium-type FER molecular sieve. Disperse the sodium-type FER molecular sieve with 6.02g of CoSO4·7H2O in 100ml of deionized water and stir and dry at 80℃. Transfer the dried mixture to a muffle furnace and calcine at 600℃ for 6 h. Prepare 296ml of 1M ammonium chloride solution, disperse the calcined molecular sieve powder in the solution, and stir at 80℃ for 4 h. After filtration, washing, and drying, the product is transferred to a muffle furnace and calcined at 500°C for 3 hours to obtain the final product.

[0055] The metal ion content of each example and comparative example was analyzed by ICP, and the results are shown in Table 1 below:

[0056] Table 1: Metal Ion Content

[0057] Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Example 8 Comparative Example 1 Comparative Example 2 Comparative Example 3 Co content (%) 2.94 / / 3.11 1.92 1.88 0.96 4.11 / 3.78 3.44 Cu content (%) / 3.96 5.03 / 3.05 1.93 2.05 0.95 / / /

[0058] It should be noted that this invention employs a two-step synthesis method. The first step involves hydrothermal crystallization to synthesize a pre-crystallized FER molecular sieve. The second step increases the hydrothermal crystallization temperature, causing the unstable molecular sieve structure to transform into a high-silicon-to-aluminum ratio defect-type crystal under high temperature and pressure, while simultaneously introducing heteroions into the molecular sieve framework. Compared to traditional techniques, this method can achieve a larger doping amount and is simpler with readily available raw materials. Its application in the catalytic synthesis of ethylene glycol dimethyl ether from ethylene glycol and methanol can achieve high conversion rates and high selectivity, demonstrating significant economic value and promising market prospects.

[0059] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. Use of a metal ion doped defect-type FER molecular sieve for catalyzing the synthesis of ethylene glycol dimethyl ether from ethylene glycol and methanol, characterized in that, The metal ion doped defect type FER molecular sieve, including a molecular sieve with Cu and Co as doped ions, the molecular sieve taking a defect type FER molecular sieve with a silicon-aluminum ratio of 30-40 as a basic framework, and the mass percentage of the doped ions being 3-5% based on the mass of the defect type FER molecular sieve; The preparation method of the metal ion doped defect type FER molecular sieve, Comprising the following steps: S1: dissolving a silicon source, an aluminum source, a template agent and a crystallization aid in deionized water and stirring uniformly, and adjusting the pH value to 10 by using a pH adjuster; S2: transferring the mixed solution to a reaction kettle, performing dynamic hydrothermal crystallization at 130-150 DEG C for the first time for 72-96 h, opening the reaction kettle after cooling to add a heteroion compound, performing dynamic hydrothermal crystallization at 200-220 DEG C for the second time for 3-5 h, and then washing, suction filtering and drying to obtain the metal ion doped defect type FER molecular sieve; S3: dispersing the metal ion doped defect type FER molecular sieve powder obtained in step S2 in an ammonium chloride solution, stirring for 2-4 h, washing, suction filtering and drying, and finally transferring to a muffle furnace to be calcined to obtain the final product; The silicon source is any one of tetraethyl orthosilicate, sodium sulfate and silica sol, the aluminum source is any one of aluminum nitrate, aluminum chloride and aluminum sulfate, the template agent is any one of pyridine, morpholine and ethylenediamine, the crystallization aid is any one of sodium sulfate and sodium chloride, and the pH adjuster is any one of H2SO4, HCl and NaOH; In S1, the molar ratio of the silicon source, the aluminum source, the template agent, the crystallization aid and water is (30-40):1:(15-20):(5-10):(700-900). In S1, the pH value is adjusted to 10 by any one of H2SO4, HCl and NaOH.

2. The use of a metal ion-doped defect-type FER molecular sieve according to claim 1 in the catalytic synthesis of ethylene glycol dimethyl ether from ethylene glycol and methanol, characterized in that, In S2, the heteroion compound is one of Cu sulfate and chloride and one of Co sulfate and chloride, and the addition amount of the heteroion compound is 3-5% of the mass of the defect type FER molecular sieve.

3. The use of a metal ion-doped defect-type FER molecular sieve according to claim 1 in the catalytic synthesis of ethylene glycol dimethyl ether from ethylene glycol and methanol, characterized in that, In S3, the concentration of the ammonium chloride solution is 1-2 M, the mass ratio of the ammonium chloride solution to the metal ion doped defect type FER molecular sieve is 10-15:1, the stirring time is 2-4 h and the stirring temperature is 50-80 DEG C.

4. The use of a metal ion-doped defect-type FER molecular sieve according to claim 1 in the catalytic synthesis of ethylene glycol dimethyl ether from ethylene glycol and methanol, characterized in that, In S3, the calcination environment is an air atmosphere and the calcination temperature is 500-550 DEG C, and the calcination time is 2-4 h.

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