Metal salt functionalized solid acid catalyst for etherification reaction and application thereof

Abstract

The invention discloses a metal salt functionalized solid acid catalyst for etherification reaction and application thereof, the catalyst can catalyze etherification reaction under mild conditions to synthesize methyl tert-butyl ether, and the catalyst shows excellent activity and selectivity. The catalyst is prepared by taking a metal salt-acid solution complex as a culture medium through an in-situ synthesis method, and the preparation method comprises the following steps: (1) preparation of the metal salt-acid solution complex: taking a metal salt as an active main body, preparing a dilute acid solution as an active functional ligand, fully stirring and dissolving at normal temperature, and filtering to obtain the metal salt-acid solution complex; a metal salt-acid solution complex is prepared; and (2) preparation of the metal salt functionalized solid acid catalyst: adopting an in-situ synthesis method, taking the metal salt-acid solution complex as a culture medium, mixing tetraethyl orthosilicate, adding an auxiliary agent, stirring to form gel, aging the gel, grinding into powder, roasting and activating to generate an acid site, and drying to obtain the metal salt functionalized solid acid catalyst. The metal salt functionalized solid acid catalyst for the etherification reaction can be prepared.

Description

Technical Field

[0001] The invention relates to a catalyst and application thereof, and more particularly to a metal salt functionalized solid acid catalyst for etherification reaction and application thereof. Background Art

[0002] Methyl tert-butyl ether (MTBE) is a high-octane, colorless and transparent liquid with excellent blending performance and stability, and is an ideal gasoline additive. It can effectively improve combustion efficiency, inhibit ozone generation, and has good miscibility with gasoline. It is widely used as a blending component for unleaded, high-octane oxygenated gasoline. In addition, MTBE is also an important chemical raw material. It can be cracked to prepare high-purity isobutylene for the production of butyl rubber and other products. With the growth of demand, the production technology of MTBE has received more and more attention.

[0003] The synthesis of methyl tert-butyl ether is mainly carried out through the etherification reaction of methanol and isobutylene under the action of an acidic catalyst. The etherification process is based on the electrophilic addition mechanism. Isobutylene, as a proton acceptor, undergoes a protonation reaction under the action of an acidic catalyst to generate a positive carbon ion. The positive carbon ion as an intermediate then quickly reacts with the nucleophilic reagent CH3O - Reaction to produce methyl tert-butyl ether. According to this mechanism, the protonation of olefins is an acid-base reaction process. Therefore, it is beneficial for the reaction when the acidity of the catalyst and the alkalinity of the olefin are strong. From the current production and application situation, resin catalysts are widely used in etherification reactions due to their acidity and selectivity, but they are also accompanied by a series of disadvantages. First, the thermal stability of resin catalysts is poor, and the sulfonic acid groups are easy to fall off and the internal pores collapse at high temperatures, resulting in a decrease in catalytic activity. Secondly, resin catalysts are very sensitive to the ratio of methanol and isobutylene, which limits their applicability under different raw material ratios. In addition, resin catalysts may cause corrosion problems and are challenging to handle after use, increasing operating costs and environmental risks. These shortcomings limit the efficiency and stability of resin catalysts in the synthesis of methyl tert-butyl ether, and have prompted researchers to find more efficient and stable alternative catalysts to improve the performance of methyl tert-butyl ether synthesis.

[0004] In the prior art, the Chinese patent with publication number CN101773848A provides an innovative preparation technology of composite rare earth oxide β molecular sieve catalyst, which modifies hydrogen β molecular sieve by using lanthanide rare earth oxide, aiming to improve the conversion rate of isobutylene in synthesis. Under the optimal reaction conditions, the isobutylene conversion rate is 80%. However, rare earth oxides are easily lost, resulting in reduced activity and stability of the catalyst, making it difficult to apply industrially. The Chinese patent with publication number CN102992965A provides a method for preparing methyl tert-butyl ether using a niobium-containing solid acid catalyst, which is prepared by impregnating γ-Al2O3 in a niobium oxalate solution and a sulfuric acid solution, respectively, and then calcining to prepare a niobium-containing solid acid catalyst. However, the thermal stability of niobium oxalate is insufficient, which limits its continuous use in high temperature environments and is easily deactivated, making it difficult for the catalyst to meet the requirements for high temperature stability and long-term durability in industrial applications. The Chinese patent with publication number CN108057458A provides a method for preparing a catalyst for synthesizing methyl tert-butyl ether, in which SBA-15 is sulfonated by concentrated sulfuric acid to produce active centers in the SBA-15 pores to catalyze methanol and tert-butyl alcohol etherification to prepare methyl tert-butyl ether. However, the sulfonic acid group is easily dissolved from the catalyst surface during the reaction, resulting in a decrease in its catalytic activity. The Chinese patent with publication number CN109232196A provides a method for preparing methyl tert-butyl ether, in which montmorillonite is loaded and modified by metal oxides to enhance its catalytic performance. However, after montmorillonite is loaded, its pores are easily blocked, affecting the mass transfer efficiency of the catalyst, and the metal oxides are expensive, and the economic benefits of industrial application are not ideal.

[0005] In view of the challenges faced by solid acid catalysts in etherification reactions in the prior art, such as diffusion problems caused by pore size limitation, easy deactivation of active sites, complex preparation process, high cost and insufficient thermal stability, these shortcomings limit their application at the industrial level. Therefore, from the perspective of industrial application, it is of great significance to develop a catalyst, preparation method and application for the efficient catalytic etherification of methanol and isobutylene to synthesize methyl tert-butyl ether. Summary of the invention

[0006] The purpose of the present invention is to provide a metal salt functionalized solid acid catalyst for etherification reaction in view of the problems existing in the industrial catalyst technology in the prior art. The catalyst can be used as a catalyst for the etherification reaction to catalyze the etherification reaction under mild conditions to synthesize methyl tert-butyl ether. The diffusion problem caused by pore size limitation, easy deactivation of active sites, complicated preparation process, high cost and thermal stability of the solid acid catalyst in the prior art are completely solved.

[0007] Another object of the present invention is to provide an application of the metal salt functionalized solid acid catalyst for etherification reaction, which can be used for the etherification reaction of methanol and isobutylene to prepare methyl tert-butyl ether. In the etherification reaction of methanol and isobutylene, the catalyst exhibits excellent activity and selectivity, and the prepared product has high quality and good purity.

[0008] The present invention is achieved through the following technical solutions:

[0009] The metal salt functionalized solid acid catalyst for etherification reaction of the present invention is prepared by an in-situ synthesis method using a metal salt-acid solution complex as a culture medium, and the preparation method comprises the following steps:

[0010] (1) Preparation of metal salt-acid solution complex: using metal salt as the active main body, preparing dilute acid solution as the active functional ligand, stirring and dissolving at room temperature to obtain the metal salt-acid solution complex;

[0011] (2) Preparation of metal salt functionalized solid acid catalyst: An in-situ synthesis method is adopted, wherein the metal salt-acid solution complex is used as a culture medium, tetraethyl orthosilicate is mixed, and an auxiliary agent is added and stirred to form a gel. After the gel is aged, it is ground into powder, and calcined to activate it to produce acidic sites, thereby obtaining a metal salt functionalized solid acid catalyst for etherification reaction.

[0012] The metal salt functionalized solid acid catalyst for etherification reaction of the present invention has a further technical solution that the mass ratio of the metal salt active body to the active functional ligand is 1:10-20; the active body metal salt is a Lewis acid metal salt; the active functional ligand dilute acid solution is a sulfuric acid solution, and the use of sulfuric acid also has a certain sulfonation effect, which can effectively improve the activity of the catalyst. A further technical solution is that the Lewis acid metal salt is one of cerium chloride, zirconium chloride, titanium chloride, cerium sulfate, copper sulfate or ferric sulfate or a combination thereof; the mass fraction of the dilute acid solution is 3%-8%.

[0013] The metal salt functionalized solid acid catalyst for etherification reaction of the present invention can also have a further technical solution that the auxiliary agent is one or a combination of methyl cellulose, ethyl cellulose, hexadecyltrimethylammonium bromide, sesbania powder, polyvinyl alcohol or N,N-dimethylaniline hydrochloride; and the molar ratio of the metal salt-acid solution complex, tetraethyl orthosilicate and the auxiliary agent is 1:0.5-1:0.0001-0.00001.

[0014] A further technical solution of the metal salt functionalized solid acid catalyst for etherification reaction of the present invention may be that the calcination temperature is 150-650° C. and the calcination time is 4-6 hours.

[0015] The invention discloses an application of the metal salt functionalized solid acid catalyst for etherification reaction prepared by the preparation method in the etherification reaction of methanol and isobutylene to prepare methyl tert-butyl ether.

[0016] The above application of the present invention, its further technical scheme comprises the following steps: first injecting methanol as a reaction solvent in a high-pressure reactor, then adding a pre-prepared metal salt functionalized solid acid catalyst for etherification reaction; after sealing, replacing with nitrogen three times to completely remove the air in the reactor; then, introducing isobutylene into the high-pressure reactor, then pressurizing and heating to carry out etherification reaction; after the reaction is completed, separating to obtain a high-purity methyl tert-butyl ether product. A further technical scheme is that the molar ratio of methanol to isobutylene is 0.8-1.2, the content of the metal salt functionalized solid acid catalyst for etherification reaction in the reaction solution is 1%-5%wt of methanol, the etherification reaction pressure is 0.6-1.5MPa, the etherification reaction temperature is 60-120°C, and the etherification reaction time is 0.5-1.5h.

[0017] A further technical solution includes the following steps: adding a water-soluble metal complex catalyst, ammonia water and ethylene dichloride to a reaction device in proportion, heating and controlling the temperature at 100-120°C for reaction, and the reaction time is 4-20 minutes. After the reaction is completed, ethyleneamine hydrochloride is obtained, and then alkali is added for neutralization, and the ethyleneamine product is separated. A further technical solution is that the amount of the water-soluble metal complex catalyst is preferably 0.1-1% of the mass of ethylene dichloride, and the ethylene dichloride is 1,2-ethylene dichloride. A further technical solution can also be that the pressure during the reaction is 1-1.5MPa, the concentration of ammonia water is 15-25%, and the molar ratio of ammonia to alkali is 4-8:1.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] The preparation process of the metal salt functionalized solid acid catalyst for etherification reaction of the present invention is simple and efficient. The metal salt active body and the acid solution active functional ligand are loaded on the mesoporous silicon-based material by an in-situ synthesis method, and the finished product can be obtained by one calcination. The method simplifies the preparation process and reduces the cost. At the same time, the high specific surface area and porosity of the mesoporous silicon base are utilized to make the metal salt uniformly dispersed, and the catalytic efficiency is high. In the etherification reaction of methanol and isobutylene, the catalyst shows excellent activity and selectivity, and the prepared product has high quality and good purity. The conversion rate of methanol in the etherification reaction can reach 99.9%, and the selectivity of methyl tert-butyl ether can reach 99.9%. The functionalized solid acid catalyst prepared by the selected Lewis acid metal salt-acid solution complex shows a good catalytic effect on the reaction system. Under the catalytic conditions of this type of catalyst, the conversion rate of the raw material is high, the selectivity of the product, i.e., methyl tert-butyl ether, is high, and there are very few by-products. Compared with traditional catalysts, the metal salt functionalized solid acid catalyst maintains good catalytic activity and stability even after repeated use, and there is no significant decrease in raw material conversion rate and product yield. It effectively overcomes the shortcomings of traditional catalysts and has important application value for the production of methyl tert-butyl ether. DETAILED DESCRIPTION

[0020] The present invention is further described below with reference to the following examples, but these examples do not limit the protection scope of the present invention.

[0021] Example 1

[0022] Preparation of metal salt functionalized solid acid catalyst (cerium chloride functionalized solid acid catalyst) for etherification reaction:

[0023] In this embodiment, cerium chloride is used as the active main body of the catalyst and sulfuric acid solution is used as the active functional ligand. 3 g of cerium chloride is dissolved in 40 ml of a 5% by mass dilute sulfuric acid solution, and after stirring and dissolving, 6.38 g of ethyl silicate and 0.4 g of polyvinyl alcohol are added. The mixture is stirred at room temperature until a gel is formed, and then the obtained gel is aged in an oven, ground, and calcined at 200° C. for 5 h to obtain a cerium chloride functionalized solid acid catalyst.

[0024] Etherification reaction:

[0025] Weigh 20g of methanol into a 100mL autoclave, add the cerium chloride functionalized solid acid catalyst according to 5% of the mass of methanol, seal, replace with nitrogen three times and then add isobutylene, pressurize the autoclave to 1.5MPa with nitrogen under the condition of alcohol-olefin molar ratio of 1, heat to 65°C, catalyze the reaction of methanol and isobutylene for 1h to obtain methyl tert-butyl ether product. According to gas chromatography analysis, the conversion rate of methanol in the etherification reaction is 96.6%, and the selectivity of methyl tert-butyl ether is 99.9%.

[0026] Example 2

[0027] Based on the cerium chloride functionalized solid acid catalyst prepared in Example 1, the reaction conditions of the etherification reaction were adjusted to 0.9, and the other reaction conditions were kept unchanged to catalyze the reaction of methanol and isobutylene to obtain methyl tert-butyl ether. According to gas chromatography analysis, the conversion rate of methanol in the etherification reaction was 100%, and the selectivity of methyl tert-butyl ether was 99.9%.

[0028] Example 3

[0029] Preparation of metal salt functionalized solid acid catalyst (zirconium chloride functionalized solid acid catalyst) for etherification reaction:

[0030] In this embodiment, zirconium chloride is used as the active main body of the catalyst and sulfuric acid solution is used as the active functional ligand. 3 g of zirconium chloride is dissolved in 40 ml of a 5% by mass dilute sulfuric acid solution, and after stirring and dissolving, 6.38 g of ethyl silicate and 0.4 g of polyvinyl alcohol are added. The mixture is stirred at room temperature until a gel is formed, and then the obtained gel is aged in an oven, ground, and calcined at 200° C. for 5 hours to obtain a zirconium chloride functionalized solid acid catalyst.

[0031] Etherification reaction:

[0032] Weigh 20g of methanol into a 100mL autoclave, add the zirconium chloride functionalized solid acid catalyst according to 5% of the weight of methanol, seal, replace with nitrogen three times and then add isobutylene, pressurize the autoclave to 1.5MPa with nitrogen under the condition of alcohol-olefin molar ratio of 1, heat to 65°C, catalyze the reaction of methanol and isobutylene for 1h to obtain methyl tert-butyl ether product. According to gas chromatography analysis, the conversion rate of methanol in the etherification reaction is 94.3%, and the selectivity of methyl tert-butyl ether is 99.9%.

[0033] Example 4

[0034] Based on the zirconium chloride functionalized solid acid catalyst prepared in Example 3, the reaction conditions of the etherification reaction were adjusted to 0.9, and the other reaction conditions were kept unchanged to catalyze the reaction of methanol and isobutylene to obtain methyl tert-butyl ether product. According to gas chromatography analysis, the conversion rate of methanol in the etherification reaction was 99.8%, and the selectivity of methyl tert-butyl ether was 99.9%.

[0035] Example 5

[0036] Preparation of metal salt functionalized solid acid catalyst (titanium chloride functionalized solid acid catalyst) for etherification reaction:

[0037] In this embodiment, titanium chloride is used as the active main body of the catalyst and sulfuric acid solution is used as the active functional ligand. 3 g of titanium chloride is dissolved in 40 ml of a 5% by mass dilute sulfuric acid solution, and after stirring and dissolving, 6.38 g of ethyl silicate and 0.4 g of polyvinyl alcohol are added. The mixture is stirred at room temperature until a gel is formed, and then the obtained gel is aged in an oven, ground, and calcined at 200° C. for 5 h to obtain a titanium chloride functionalized solid acid catalyst.

[0038] Etherification reaction:

[0039] Weigh 20g of methanol and add it to a 100mL autoclave, add the titanium chloride functionalized solid acid catalyst according to 5% of the weight of methanol, seal it, replace it with nitrogen three times and then add isobutylene, under the condition that the alcohol-olefin molar ratio is 1, pressurize the autoclave with nitrogen to 1.5MPa, heat it to 65°C, catalyze the reaction of methanol and isobutylene for 1h to obtain methyl tert-butyl ether product. According to gas chromatography analysis, the conversion rate of methanol in the etherification reaction is 93.9%, and the selectivity of methyl tert-butyl ether is 99.9%.

[0040] Example 6

[0041] Based on the titanium chloride functionalized solid acid catalyst prepared in Example 5, the reaction conditions of the etherification reaction were adjusted to 0.9, and the other reaction conditions were kept unchanged to catalyze the reaction of methanol and isobutylene to obtain methyl tert-butyl ether. According to gas chromatography analysis, the conversion rate of methanol in the etherification reaction was 99.2%, and the selectivity of methyl tert-butyl ether was 99.9%.

[0042] Example 7

[0043] Preparation of metal salt functionalized solid acid catalyst (cerium sulfate functionalized solid acid catalyst) for etherification reaction:

[0044] In this embodiment, cerium sulfate is used as the active main body of the catalyst and sulfuric acid solution is used as the active functional ligand. 3 g of cerium sulfate is dissolved in 40 ml of a 5% by mass dilute sulfuric acid solution, and after stirring and dissolving, 6.38 g of ethyl silicate and 0.4 g of polyvinyl alcohol are added. The mixture is stirred at room temperature until a gel is formed, and then the obtained gel is aged in an oven, ground, and calcined at 250° C. for 5 h to obtain a cerium sulfate functionalized solid acid catalyst.

[0045] Etherification reaction:

[0046] Weigh 20g of methanol and add it to a 100mL autoclave, add the above-mentioned cerium sulfate functionalized solid acid catalyst according to 5% of the weight of methanol, seal it, replace it with nitrogen three times and then fill it with isobutylene. Under the condition that the alcohol-olefin molar ratio is 1, pressurize the autoclave with nitrogen to 1.5MPa, heat it to 65°C, and catalyze the reaction of methanol and isobutylene for 1h to obtain methyl tert-butyl ether product. According to gas chromatography analysis, the conversion rate of methanol in the etherification reaction is 94.7%, and the selectivity of methyl tert-butyl ether is 99.9%.

[0047] Example 8

[0048] Based on the cerium sulfate functionalized solid acid catalyst prepared in Example 7, the reaction conditions of the etherification reaction were adjusted to 0.9, and the other reaction conditions were kept unchanged to catalyze the reaction of methanol and isobutylene to obtain methyl tert-butyl ether product. According to gas chromatography analysis, the conversion rate of methanol in the etherification reaction was 99.9%, and the selectivity of methyl tert-butyl ether was 99.9%.

[0049] Example 9

[0050] Preparation of metal salt functionalized solid acid catalyst (copper sulfate functionalized solid acid catalyst) for etherification reaction:

[0051] In this embodiment, copper sulfate is used as the active main body of the catalyst and sulfuric acid solution is used as the active functional ligand. 3 g of copper sulfate is dissolved in 40 ml of a 5% by mass dilute sulfuric acid solution, and after stirring and dissolving, 6.38 g of ethyl silicate and 0.4 g of polyvinyl alcohol are added. The mixture is stirred at room temperature until a gel is formed, and then the obtained gel is aged in an oven, ground, and calcined at 250° C. for 5 h to obtain a copper sulfate functionalized solid acid catalyst.

[0052] Etherification reaction:

[0053] 20 g of methanol was weighed and added to a 100 mL autoclave, and the copper sulfate functionalized solid acid catalyst was added at 5% of the mass of methanol, and the autoclave was sealed, and isobutylene was charged after nitrogen replacement three times. Under the condition that the alcohol-olefin molar ratio was 1, the autoclave was pressurized to 1.5 MPa with nitrogen, and the temperature was raised to 65° C., and the methanol and isobutylene were catalyzed to react for 1 hour to obtain methyl tert-butyl ether product. According to gas chromatography analysis, the conversion rate of methanol in the etherification reaction was 93.1%, and the selectivity of methyl tert-butyl ether was 99.9%.

[0054] Example 10

[0055] Based on the copper sulfate functionalized solid acid catalyst prepared in Example 9, the reaction conditions of the etherification reaction were adjusted to 0.9, and the other reaction conditions were kept unchanged to catalyze the reaction of methanol and isobutylene to obtain methyl tert-butyl ether product. According to gas chromatography analysis, the conversion rate of methanol in the etherification reaction was 99.3%, and the selectivity of methyl tert-butyl ether was 99.9%.

[0056] Embodiment 11

[0057] Preparation of metal salt functionalized solid acid catalyst (ferric sulfate functionalized solid acid catalyst) for etherification reaction:

[0058] In this embodiment, ferric sulfate is used as the active main body of the catalyst and sulfuric acid solution is used as the active functional ligand. 3 g of ferric sulfate is dissolved in 40 ml of a 5% by mass dilute sulfuric acid solution, and after stirring and dissolving, 6.38 g of ethyl silicate and 0.4 g of polyvinyl alcohol are added. The mixture is stirred at room temperature until a gel is formed, and then the obtained gel is aged in an oven, ground, and calcined at 250° C. for 5 h to obtain a ferric sulfate functionalized solid acid catalyst.

[0059] Etherification reaction:

[0060] Weigh 20g of methanol and add it to a 100mL autoclave, add the above-mentioned iron sulfate functionalized solid acid catalyst according to 5% of the weight of methanol, seal it, replace it with nitrogen three times and then fill it with isobutylene. Under the condition that the alcohol-olefin molar ratio is 1, pressurize the autoclave with nitrogen to 1.5MPa, heat it to 65°C, and catalyze the reaction of methanol and isobutylene for 1h to obtain methyl tert-butyl ether product. According to gas chromatography analysis, the conversion rate of methanol in the etherification reaction is 92.3%, and the selectivity of methyl tert-butyl ether is 99.9%.

[0061] Example 12

[0062] Based on the ferric sulfate functionalized solid acid catalyst prepared in Example 11, the reaction conditions of the etherification reaction were adjusted to 0.9, and the other reaction conditions were kept unchanged to catalyze the reaction of methanol and isobutylene to obtain methyl tert-butyl ether product. According to gas chromatography analysis, the conversion rate of methanol in the etherification reaction was 99.1%, and the selectivity of methyl tert-butyl ether was 99.9%.

[0063] Example 13

[0064] The cerium chloride functionalized solid acid catalyst prepared in Example 1 was subjected to a recycling experiment, and the raw material catalyst ratio and reaction conditions were controlled to remain unchanged. When the alcohol-olefin molar ratio was 1, the results of three recycling experiments were as follows:

[0065] (1) The methanol conversion rate was 96.6%, and the selectivity of methyl tert-butyl ether was 99.9%.

[0066] (2) The methanol conversion rate was 96.5%, and the selectivity of methyl tert-butyl ether was 99.9%.

[0067] (3) The methanol conversion rate was 96.6%, and the selectivity of methyl tert-butyl ether was 99.9%.

[0068] When the catalyst is recycled for three times, the methanol conversion rate exceeds 96% and the selectivity of methyl tert-butyl ether does not decrease.

[0069] Embodiment 14

[0070] The cerium sulfate functionalized solid acid catalyst prepared in Example 7 was subjected to a recycling experiment, and the raw material catalyst ratio and reaction conditions were controlled to remain unchanged. When the alcohol-olefin molar ratio was 1, the results of three recycling experiments were as follows:

[0071] (1) The methanol conversion rate was 94.6%, and the selectivity of methyl tert-butyl ether was 99.9%.

[0072] (2) The methanol conversion rate was 94.2%, and the selectivity of methyl tert-butyl ether was 99.9%.

[0073] (3) The methanol conversion rate was 94.7%, and the selectivity of methyl tert-butyl ether was 99.9%.

[0074] When the catalyst is recycled for three times, the methanol conversion rate exceeds 94% and the selectivity of methyl tert-butyl ether does not decrease.

[0075] Embodiment 15

[0076] The copper sulfate functionalized solid acid catalyst prepared in Example 9 was subjected to a recycling experiment, and the raw material catalyst ratio and reaction conditions were controlled to remain unchanged. When the alcohol-olefin molar ratio was 1, the results of three recycling experiments were as follows:

[0077] (1) The methanol conversion rate was 93.2%, and the selectivity of methyl tert-butyl ether was 99.9%.

[0078] (2) The methanol conversion rate was 93.0%, and the selectivity of methyl tert-butyl ether was 99.9%.

[0079] (3) The methanol conversion rate was 93.1%, and the selectivity of methyl tert-butyl ether was 99.9%.

[0080] When the catalyst is recycled for three times, the methanol conversion rate exceeds 93% and the selectivity of methyl tert-butyl ether does not decrease.

[0081] The results of etherification products under different catalysts and reaction conditions of Examples 1-12 are shown in Table 1.

[0082] Table 1 Etherification product results under different catalysts and reaction conditions in Examples 1-12

[0083]

[0084] Experimental data analysis:

[0085] According to the results of Examples 1-12, it is shown that the functionalized solid acid catalyst prepared by the Lewis acid metal salt-acid solution complex exhibits a good catalytic effect on the reaction system. Under the catalytic conditions of this type of catalyst, the conversion rate of the raw material is high, the selectivity of the product, i.e., methyl tert-butyl ether, is high, and there are very few by-products.

[0086] According to the results of Examples 13-15, three different catalysts among the metal salt functionalized solid acid catalysts were selected for repeated use multiple times, and the catalysts still maintained a very high catalytic activity and the selectivity was not reduced, which fully verified the stability of the catalyst, which can be reused multiple times and has great industrial application prospects.

Claims

1. A metal salt functionalized solid acid catalyst for etherification reaction, characterized in that: The metal salt functionalized solid acid catalyst is prepared by an in-situ synthesis method using a metal salt-acid solution complex as a culture medium. The preparation method comprises the following steps: (1) Preparation of metal salt-acid solution complex: using metal salt as the active main body, preparing dilute acid solution as the active functional ligand, stirring and dissolving at room temperature to prepare the metal salt-acid solution complex; (2) Preparation of metal salt functionalized solid acid catalyst: An in-situ synthesis method is adopted, wherein the metal salt-acid solution complex is used as a culture medium, tetraethyl orthosilicate is mixed, and an auxiliary agent is added and stirred to form a gel. After the gel is aged, it is ground into powder, and calcined to activate it to produce acidic sites, thereby obtaining a metal salt functionalized solid acid catalyst for etherification reaction.

2. The metal salt functionalized solid acid catalyst for etherification reaction according to claim 1, characterized in that: The mass ratio of the metal salt active body to the active functional ligand is 1:10-20; the active body metal salt is a Lewis acid metal salt; and the active functional ligand dilute acid solution is a sulfuric acid solution.

3. The metal salt functionalized solid acid catalyst for etherification reaction according to claim 2, characterized in that: The Lewis acid metal salt is one of cerium chloride, zirconium chloride, titanium chloride, cerium sulfate, copper sulfate or ferric sulfate or a combination thereof; the mass fraction of the dilute acid solution is 3%-8%.

4. The metal salt functionalized solid acid catalyst for etherification reaction according to claim 1, characterized in that: The auxiliary agent is one of methyl cellulose, ethyl cellulose, hexadecyltrimethylammonium bromide, sesbania powder, polyvinyl alcohol or N,N-dimethylaniline hydrochloride or a combination thereof; the molar ratio of the metal salt-acid solution complex, tetraethyl orthosilicate and the auxiliary agent is 1:0.5-1:0.0001-0.00001.

5. The metal salt functionalized solid acid catalyst for etherification reaction according to claim 1, characterized in that: The calcination temperature is 150-650°C, and the calcination time is 4-6h.

6. Use of a metal salt functionalized solid acid catalyst for etherification reaction prepared by the preparation method according to any one of claims 1 to 5 in the etherification reaction of methanol and isobutylene to prepare methyl tert-butyl ether.

7. The use according to claim 6, characterized in that: The method comprises the following steps: firstly injecting methanol as a reaction solvent into a high-pressure reactor, and then adding a pre-prepared metal salt functionalized solid acid catalyst for etherification reaction; after sealing, replacing with nitrogen three times to completely remove the air in the reactor; then, introducing isobutylene into the high-pressure reactor, and then pressurizing and heating to carry out etherification reaction; after the reaction is completed, obtaining a high-purity methyl tert-butyl ether product by separation.

8. The use according to claim 7, characterized in that: The molar ratio of methanol to isobutylene is 0.8-1.2, the content of metal salt functionalized solid acid catalyst for etherification reaction in the reaction solution is 1%-5%wt of methanol, the etherification reaction pressure is 0.6-1.5MPa, the etherification reaction temperature is 60-120°C, and the etherification reaction time is 0.5-1.5h.

Images