Preparation process for synthesizing tert-butylamine by adopting methyl tert-butyl ether

Abstract

The invention belongs to the technical field of tert-butylamine preparation, and particularly relates to a preparation process for synthesizing tert-butylamine by adopting methyl tert-butyl ether. The preparation process comprises the following steps: preparing calcium alginate microspheres; preparing an SAPO precursor solution; performing composite crystallization; preparing an SAPO-11 carrier; preparing an ammonium type SAPO-11 carrier; preparing a metal supported catalyst; preparing an activated catalyst; methyl tert-butyl ether and liquid ammonia are used as raw materials, and tert-butylamine is prepared under the catalysis of an activated catalyst. According to the preparation process for synthesizing the tert-butylamine by adopting the methyl tert-butyl ether, the process of catalytically synthesizing the tert-butylamine by taking the methyl tert-butyl ether and the ammonia as raw materials follows an acid catalytic cracking nucleophilic addition coupling mechanism, and the prepared hierarchical pore CuZn / HSAPO11 catalyst remarkably reduces the reaction activation energy through the synergistic effect of B acid, L acid and metal active sites; high-activity and high-selectivity catalytic conversion at low temperature is realized, and high-purity tert-butylamine is prepared.

Description

Technical Field

[0001] This invention belongs to the field of tert-butylamine preparation technology, specifically relating to a preparation process for synthesizing tert-butylamine using methyl tert-butyl ether. Background Technology

[0002] tert-butylamine is an important organic synthesis intermediate, widely used in the synthesis of rubber vulcanization accelerators, drugs (rifampicin), insecticides, fungicides, herbicides, dyes, etc. Currently, the main methods for producing tert-butylamine are: (1) HCN-MTBE method, namely hydrogen cyanide-methyl tert-butyl ether method. MTBE and hydrogen cyanide are first reacted with concentrated sulfuric acid to generate tert-butylformamide, and then methanol is used to hydrolyze it to generate tert-butylamine. However, because the process route contains cyanide, there is a great danger in the production. (2) tert-butanol urea method: urea and tert-butanol are reacted at 10-20℃ to generate tert-butylurea, and then hydrolyzed under alkaline conditions to obtain tert-butylamine. The synthesis of tert-butylamine in this route uses a high-boiling-point solvent - ethylene glycol, which can be recycled, but the energy consumption is relatively high and the effect is not good. (3) Isobutylene catalytic amination method: tert-butylamine is obtained by direct gas-phase catalytic amination of isobutylene and ammonia. At 300℃ and 500MPa, with iron-silicon as the catalyst and an ammonia to isobutylene ratio of 5:1, the selectivity of tert-butylamine was 97.6%; with diatomaceous earth as the catalyst and an ammonia to isobutylene ratio of 2:1, the selectivity of tert-butylamine obtained at 300℃ and 250MPa was 99.8%, and the unreacted raw materials could be recycled. It can be seen that this process requires high temperature and high pressure conditions, and the process conditions are harsh, making it unsuitable for domestic production. (4) N-tert-butylphenylacetamide hydrolysis method. This process was successfully developed by Bayer AG of Germany in 1983. The mass fraction of tert-butylamine was 95.6%, and the total yield of the two steps exceeded 75%. N-tert-butylphenylacetamide can also be obtained by reacting styrene with tert-butanol, and then phenylacetic acid and tert-butylamine can be obtained by alkaline hydrolysis. However, this process is difficult to form a large-scale industrial production.

[0003] In summary, existing tert-butylamine production processes all suffer from problems such as relatively harsh reaction conditions, high energy consumption, poor safety, or difficulty in large-scale production. Therefore, it is necessary to explore a novel preparation process for tert-butylamine. Summary of the Invention

[0004] The objective of this invention is to provide a process for synthesizing tert-butylamine using methyl tert-butyl ether. The tert-butylamine prepared by this process exhibits high yield and purity.

[0005] The preparation process for synthesizing tert-butylamine using methyl tert-butyl ether as described in this invention comprises the following steps: (1) Preparation of calcium alginate microspheres: Sodium alginate and starch were added to deionized water and stirred in a water bath at 40°C for 2 hours to obtain a composite solution. Then, the composite solution was added to a liquid paraffin-Span80 mixture and stirred at 800 r / min for 12 minutes to form an emulsion. 0.2 mol / L calcium chloride solution was added dropwise to the emulsion and stirred for another 30 minutes. The mixture was then crosslinked and cured at room temperature for 80 minutes. Finally, the microspheres were separated by centrifugation at 3000 r / min for 5 minutes and washed three times with deionized water to obtain wet calcium alginate gel microspheres. The wet calcium alginate gel microspheres were dried in a vacuum freeze dryer at -50°C for 24 hours until the mass of the microspheres no longer changed, thus obtaining semi-dry microspheres. The semi-dry microspheres were classified by an air classifier and microspheres with a particle size of 40-50 μm were obtained. (2) Preparation of SAPO precursor solution; (3) Composite crystallization: Microspheres with a particle size of 40-50 μm obtained in step (1) are directly added to the SAPO precursor solution prepared in step (2) for isothermal crystallization; (4) Preparation of SAPO-11 carrier by washing, drying and calcination; (5) Acid washing to remove calcium carbonate and water washing and drying to prepare ammonium-type SAPO-11 support; (6) Preparation of metal-supported catalysts by impregnation with active metals; (7) Activate the metal-supported catalyst to prepare an activated catalyst; (8) Tert-butylamine was prepared using methyl tert-butyl ether and liquid ammonia as raw materials under the catalysis of an activated catalyst.

[0006] In step (1), starch accounts for 15% of the mass of sodium alginate.

[0007] In step (1), the mass-volume ratio of sodium alginate to deionized water is 1.5:100, with units of g / mL.

[0008] The liquid paraffin-Span80 mixture mentioned in step (1) is made by adding Span80 (sorbitan monooleate) to liquid paraffin and stirring until completely dissolved. The mass-volume ratio of Span80 to liquid paraffin is 6:500, and the unit is g / mL.

[0009] In step (1), the volume ratio of the composite adhesive to the liquid paraffin-Span80 mixture is 1:5.

[0010] In step (1), the composite adhesive solution is added dropwise to the liquid paraffin-Span80 mixture, and the dropping speed is controlled at 3 mL / min.

[0011] The concentration of the calcium chloride solution in step (1) is 0.2 mol / L.

[0012] The semi-dry microspheres prepared in step (1) have a particle size of 40-50 μm after airflow classification. This uniform particle size ensures that the SAPO-11 precursor liquid can fully penetrate and form a mesoporous structure with concentrated pore size distribution after crystallization.

[0013] The preparation method of the SAPO precursor solution in step (2) is as follows: Boehmite is added to deionized water and stirred evenly. Then, phosphoric acid is added dropwise. After the addition is complete, stirring is continued for 1 hour until completely clear and transparent. Tetraethyl orthosilicate is added and stirring is continued for 1 hour until the tetraethyl orthosilicate is fully hydrolyzed. Finally, di-n-propylamine is added and stirring is continued for 1 hour until the gel is uniform. The gel is aged in a 90°C water bath for 24 hours to obtain the SAPO precursor solution. The mass ratio of boehmite to deionized water is 1:8. The content of calcined Al2O3 in boehmite is 68% by mass percentage. The mass concentration of phosphoric acid is 85%. Based on the Al2O3 in boehmite, the molar ratio of phosphoric acid to Al2O3 is controlled at 1.1:1. Based on the Al2O3 in boehmite, the molar ratio of tetraethyl orthosilicate to Al2O3 is controlled at 0.15:1. 1; Based on Al2O3 in pseudoboehmite, the molar ratio of di-n-propylamine to Al2O3 was controlled to be 2.0 : 1.

[0014] The specific steps of the composite crystallization in step (3) are as follows: the microspheres with a particle size of 40-50 μm prepared in step (1) are directly added to the SAPO precursor solution prepared in step (2), ultrasonically dispersed for 15 min, stirred at room temperature for 2 h, and after stopping stirring, transferred to a polytetrafluoroethylene-lined high-pressure reactor, heated to 180 °C at a rate of 1.5 °C / min, and crystallized at constant temperature under autogenous pressure for 30 h, and finally naturally cooled to room temperature; wherein: the mass ratio of microspheres with a particle size of 40-50 μm to SAPO precursor solution is 1:8-12.

[0015] The preparation of SAPO-11 support by washing, drying and calcining in step (4) specifically involves discarding the supernatant, taking out the solid after isothermal crystallization, washing the obtained solid with deionized water by centrifugation 4-5 times until the pH of the washing solution is 7, and then drying it at 110℃ for 12h to obtain powder. The powder is then placed in a muffle furnace for calcination. After calcination, the powder is cooled to room temperature with the furnace to obtain SAPO-11 support. The calcination is carried out in an air atmosphere, with the temperature increased to 120℃ at a heating rate of 2℃ / min and held for 1h, then increased to 300℃ at a heating rate of 2℃ / min and held for 2h, and finally increased to 580℃ at a heating rate of 5℃ / min and held for 4h.

[0016] The acid washing to remove calcium carbonate and the water washing and drying in step (5) are as follows: the SAPO-11 support is immersed in 0.1 mol / L hydrochloric acid and stirred at room temperature for 1 h. Then the solid is filtered out and immersed in 0.5 mol / L ammonium chloride solution. The solid is stirred at 80 °C for 2 h for separation and exchange. Then it is centrifuged and washed with deionized water until pH=7.0. Finally, it is dried at 110 °C for 12 h to prepare the ammonium type SAPO-11 support. The mass-volume ratio of solid to ammonium chloride is 1:10, and the unit is g / mL.

[0017] In step (5), hydrochloric acid is first used to remove most of the calcium carbonate and soluble calcium salts, and then ammonium chloride is added for ion exchange to remove the remaining Ca. 2+ Na + Cation exchange is equal to NH4 + .

[0018] In step (5), since the organic components of calcium alginate have been decomposed and transformed in step (3) hydrothermal isothermal crystallization and step (4) high-temperature calcination, the obtained SAPO-11 carrier is mainly composed of an inorganic porous framework. Its molecular sieve structure can withstand dilute hydrochloric acid treatment to remove CaCO3 hard template and soluble impurities. After ammonium exchange, a pure phase ammonium type SAPO-11 carrier is obtained.

[0019] The preparation of metal-supported catalyst by impregnation of active metal in step (6) is as follows: copper nitrate and zinc nitrate are dissolved in deionized water to prepare a mixed solution, and an ammonium-type SAPO-11 support is impregnated with an equal volume. After impregnation, the solution is aged at room temperature for 12 hours, and then dried and calcined to prepare the metal-supported catalyst. The drying temperature is 110℃, the drying time is 12 hours, the calcination atmosphere is air, the calcination temperature is 500℃, and the calcination time is 4 hours. In the prepared metal-supported catalyst, the mass of copper oxide accounts for 5.5-5.7% of the total mass of the catalyst, the mass of zinc oxide accounts for 3.4-3.6% of the total mass of the catalyst, and the mass of the ammonium-type SAPO-11 support accounts for 90.8-91.0% of the total mass of the catalyst.

[0020] The activation treatment of the metal-supported catalyst in step (7) to prepare the activated catalyst is specifically as follows: the metal-supported catalyst prepared in step (6) is loaded into a fixed-bed reactor, hydrogen atmosphere is introduced, the temperature is raised to 365-375℃ at a heating rate of 2℃ / min, and the temperature is kept constant for 3.6-3.7h. After the reduction is completed, the catalyst is cooled to 165-170℃ in hydrogen atmosphere to obtain the activated catalyst.

[0021] Step (8) describes the preparation of tert-butylamine using methyl tert-butyl ether and liquid ammonia as raw materials under the catalysis of an activated catalyst. Specifically, methyl tert-butyl ether is pumped into preheating vaporizer A via a metering pump, and the vaporization temperature is controlled at 115°C to vaporize it into a gaseous phase. Liquid ammonia is pumped into preheating vaporizer B via a metering pump, and converted into high-pressure superheated gaseous ammonia at 2.0 MPa and 145°C. The two materials are thoroughly mixed in a mixer to obtain a superheated mixed raw material. After being heated to 175°C by preheater C, it enters the reactor and undergoes a continuous gas-phase catalytic ammonolysis reaction from top to bottom through the catalyst bed. The reaction effluent is then processed through… The reactor outlet condenser cools the mixture to 25°C, causing tert-butylamine and unreacted methyl tert-butyl ether to condense into a liquid phase. Unreacted gaseous ammonia is separated into gas and liquid phases and then compressed and recycled. The condensed liquid product is then washed in a water washing tower to remove dissolved ammonia before being fed into a distillation column operating at atmospheric pressure. The column top temperature is controlled at 44°C to collect high-purity tert-butylamine, while the column bottom temperature is controlled at 60°C to collect unreacted methyl tert-butyl ether, which is recycled back to the reactor inlet. The molar ratio of liquid ammonia to methyl tert-butyl ether is 4-6:1, the reaction temperature is 175°C, the reaction pressure is 2.0 MPa, and the mass hourly space velocity (WHSV) of methyl tert-butyl ether is 1.0 h⁻¹. -1 .

[0022] Compared with the prior art, the present invention has the following advantages: (1) The preparation process of tert-butylamine using methyl tert-butyl ether described in this invention follows the acid-catalyzed cracking nucleophilic addition coupling mechanism. The prepared hierarchical porous CuZn / HSAPO11 catalyst significantly reduces the reaction activation energy through the synergistic effect of Brønsted acid, Lewis acid and metal active sites, achieving high-activity and high-selectivity catalytic conversion at low temperature, and preparing high-purity tert-butylamine.

[0023] (2) The preparation process for synthesizing tert-butylamine using methyl tert-butyl ether described in this invention uses an activated catalyst, with the HSAPO11 support providing suitable Brønsted acid sites, to efficiently catalyze the directional cracking of methyl tert-butyl ether. After acid washing and ammonium exchange treatment, the support forms a high-purity hydrogen-form SAPO11 framework. The hydroxyl groups in this framework constitute moderately strong Brønsted acid active centers, which can protonate and activate the tert-butyl-oxygen bond in the methyl tert-butyl ether molecule, promoting the selective cleavage of the CO bond, generating a tert-butyl carbocation and releasing methanol. Compared with traditional strong acid catalysts, this mild Brønsted acid site can avoid excessive cracking of methyl tert-butyl ether and the occurrence of side reactions. At the same time, the catalyst has a hierarchical porous structure, which greatly shortens the diffusion path of reactants and intermediates, eliminates the microporous diffusion limitation, and allows the cracking step to proceed rapidly at low temperatures, laying the foundation for low-temperature high activity. The introduced Zn active component is Zn 2+ The form is highly dispersed on the carrier surface, Zn 2+As a Lewis acid site, it promotes the enrichment and coordination activation of NH3 on the catalyst surface, optimizes the collision between ammonia and carbocations, and accelerates nucleophilic addition. The activation effect of the Lewis acid site on NH3 effectively lowers the energy barrier of the addition step, matching the formation rate of the Brønsted acid cleavage step, avoiding side reactions caused by carbocation accumulation, and significantly improving the selectivity of tert-butylamine while enhancing catalytic activity. After hydrogen reduction, the Cu component is in the form of metallic Cu. 0 It exists in a form that stabilizes the reaction intermediate through metal-support interactions, promoting electron rearrangement and product desorption after CN bond formation; simultaneously, Cu 0 With Zn 2+ Formation of Cu 0 -Zn 2+ The interface has bifunctional sites that optimize the adsorption state of ammonia through surface electronic effects, enabling the reaction to proceed efficiently at low temperatures.

[0024] (3) The preparation process of tert-butylamine using methyl tert-butyl ether described in this invention involves the gradual decomposition of calcium alginate template under hydrothermal conditions at 180°C to generate calcium-containing solid residues and gaseous products. CaCO3 occupies space as an in-situ hard template during crystallization. After being removed by acid washing, a mesoporous structure with concentrated pore size distribution is formed, and finally a multi-level porous SAPO-11 carrier is obtained. Detailed Implementation

[0025] Example 1 The preparation process for synthesizing tert-butylamine using methyl tert-butyl ether as described in Example 1 consists of the following steps: (1) Preparation of calcium alginate microspheres: Sodium alginate and starch were added to deionized water and stirred in a water bath at 40°C for 2 hours to obtain a composite solution. Then, the composite solution was added to a liquid paraffin-Span80 mixture and stirred at 800 r / min for 12 minutes to form an emulsion. 0.2 mol / L calcium chloride solution was added dropwise to the emulsion and stirred for another 30 minutes. The mixture was then crosslinked and cured at room temperature for 80 minutes. Finally, the microspheres were separated by centrifugation at 3000 r / min for 5 minutes and washed three times with deionized water to obtain wet calcium alginate gel microspheres. The wet calcium alginate gel microspheres were dried in a vacuum freeze dryer at -50°C for 24 hours until the mass of the microspheres no longer changed, thus obtaining semi-dry microspheres. The semi-dry microspheres were classified by an air classifier and microspheres with a particle size of 40-50 μm were obtained. (2) Preparation of SAPO precursor solution; (3) Composite crystallization: Microspheres with a particle size of 40-50 μm obtained in step (1) are directly added to the SAPO precursor solution prepared in step (2) for isothermal crystallization; (4) Preparation of SAPO-11 carrier by washing, drying and calcination; (5) Acid washing to remove calcium carbonate and water washing and drying to prepare ammonium-type SAPO-11 support; (6) Preparation of metal-supported catalysts by impregnation with active metals; (7) Activate the metal-supported catalyst to prepare an activated catalyst; (8) Tert-butylamine was prepared using methyl tert-butyl ether and liquid ammonia as raw materials under the catalysis of an activated catalyst.

[0026] In step (1), starch accounts for 15% of the mass of sodium alginate.

[0027] In step (1), the mass-volume ratio of sodium alginate to deionized water is 1.5:100, with units of g / mL.

[0028] The liquid paraffin-Span80 mixture mentioned in step (1) is made by adding Span80 (sorbitan monooleate) to liquid paraffin and stirring until completely dissolved. The mass-volume ratio of Span80 to liquid paraffin is 6:500, and the unit is g / mL.

[0029] In step (1), the volume ratio of the composite adhesive to the liquid paraffin-Span80 mixture is 1:5.

[0030] In step (1), the composite adhesive solution is added dropwise to the liquid paraffin-Span80 mixture, and the dropping speed is controlled at 3 mL / min.

[0031] The concentration of the calcium chloride solution in step (1) is 0.2 mol / L.

[0032] The semi-dry microspheres prepared in step (1) have a particle size of 40-50 μm after airflow classification. This uniform particle size ensures that the SAPO-11 precursor liquid can fully penetrate and form a mesoporous structure with concentrated pore size distribution after crystallization.

[0033] The preparation method of the SAPO precursor solution in step (2) is as follows: Boehmite is added to deionized water and stirred evenly. Then, phosphoric acid is added dropwise. After the addition is complete, stirring is continued for 1 hour until completely clear and transparent. Tetraethyl orthosilicate is added and stirring is continued for 1 hour until the tetraethyl orthosilicate is fully hydrolyzed. Finally, di-n-propylamine is added and stirring is continued for 1 hour until the gel is uniform. The gel is aged in a 90°C water bath for 24 hours to obtain the SAPO precursor solution. The mass ratio of boehmite to deionized water is 1:8. The content of calcined Al2O3 in boehmite is 68% by mass percentage. The mass concentration of phosphoric acid is 85%. Based on the Al2O3 in boehmite, the molar ratio of phosphoric acid to Al2O3 is controlled at 1.1:1. Based on the Al2O3 in boehmite, the molar ratio of tetraethyl orthosilicate to Al2O3 is controlled at 0.15:1. 1; Based on Al2O3 in pseudoboehmite, the molar ratio of di-n-propylamine to Al2O3 was controlled to be 2.0 : 1.

[0034] The specific steps of the composite crystallization in step (3) are as follows: the microspheres with a particle size of 40-50 μm prepared in step (1) are directly added to the SAPO precursor solution prepared in step (2), ultrasonically dispersed for 15 min, and then slowly stirred at room temperature for 2 h. After stopping the stirring, the mixture is transferred to a polytetrafluoroethylene-lined high-pressure reactor, heated to 180 °C at a rate of 1.5 °C / min, and crystallized at constant temperature under autogenous pressure for 30 h. Finally, it is naturally cooled to room temperature. The mass ratio of the microspheres with a particle size of 40-50 μm to the SAPO precursor solution is 1:10.

[0035] The preparation of SAPO-11 support by washing, drying and calcining in step (4) specifically involves discarding the supernatant, taking out the solid after isothermal crystallization, washing the obtained solid four times with deionized water until the pH of the washing solution is 7, drying it at 110℃ for 12 hours to obtain powder, placing the powder in a muffle furnace for calcination, and cooling it to room temperature with the furnace after calcination to obtain SAPO-11 support; wherein, the calcination is carried out in an air atmosphere, heating to 120℃ at a heating rate of 2℃ / min and holding for 1 hour, then heating to 300℃ at a heating rate of 2℃ / min and holding for 2 hours, and finally heating to 580℃ at a heating rate of 5℃ / min and holding for 4 hours.

[0036] The acid washing to remove calcium carbonate and the water washing and drying in step (5) are as follows: the SAPO-11 support is immersed in 0.1 mol / L hydrochloric acid and stirred at room temperature for 1 h. Then the solid is filtered out and immersed in 0.5 mol / L ammonium chloride solution. The solid is stirred at 80 °C for 2 h for separation and exchange. Then it is centrifuged and washed with deionized water until pH=7.0. Finally, it is dried at 110 °C for 12 h to prepare the ammonium type SAPO-11 support. The mass-volume ratio of solid to ammonium chloride is 1:10, and the unit is g / mL.

[0037] In step (5), hydrochloric acid is first used to remove most of the calcium carbonate and soluble calcium salts, and then ammonium chloride is added for ion exchange to remove the remaining Ca. 2+ Na + Cation exchange is equal to NH4 + .

[0038] In step (5), since the organic components of calcium alginate have been decomposed and transformed in step (3) hydrothermal isothermal crystallization and step (4) high-temperature calcination, the obtained SAPO-11 carrier is mainly composed of an inorganic porous framework. Its molecular sieve structure can withstand dilute hydrochloric acid treatment to remove CaCO3 hard template and soluble impurities. After ammonium exchange, a pure phase ammonium type SAPO-11 carrier is obtained.

[0039] The preparation of metal-supported catalyst by impregnation of active metal in step (6) is as follows: copper nitrate and zinc nitrate are dissolved in deionized water to prepare a mixed solution, and an ammonium-type SAPO-11 support is impregnated with an equal volume. After impregnation, the solution is aged at room temperature for 12 hours, and then dried and calcined to prepare a metal-supported catalyst. The drying temperature is 110°C, the drying time is 12 hours, the calcination atmosphere is air, the calcination temperature is 500°C, and the calcination time is 4 hours. In the prepared metal-supported catalyst, the mass of copper oxide accounts for 5.5% of the total mass of the catalyst, the mass of zinc oxide accounts for 3.5% of the total mass of the catalyst, and the mass of the ammonium-type SAPO-11 support accounts for 91% of the total mass of the catalyst.

[0040] The activation treatment of the metal-supported catalyst in step (7) to prepare the activated catalyst is as follows: the metal-supported catalyst prepared in step (6) is loaded into a fixed-bed reactor, hydrogen atmosphere is introduced, the temperature is raised to 370℃ at a heating rate of 2℃ / min, and the temperature is kept constant for 3.6h. After the reduction is completed, the catalyst is cooled to 167℃ in hydrogen atmosphere to obtain the activated catalyst.

[0041] Analysis showed that the specific surface area of ​​the activated BET catalyst prepared in step (7) was 251 m². 2 / g, most probable pore size is 5.2nm, pore volume is 0.35cm³. 3 / g.

[0042] Step (8) describes the preparation of tert-butylamine using methyl tert-butyl ether and liquid ammonia as raw materials under the catalysis of an activated catalyst. Specifically, methyl tert-butyl ether is fed into preheating vaporizer A via a metering pump, and the vaporization temperature is controlled at 115°C to vaporize it into a gaseous phase. Liquid ammonia is fed into preheating vaporizer B via a metering pump, and converted into high-pressure superheated gaseous ammonia at 2.0 MPa and 145°C. The two materials are thoroughly mixed in a mixer to obtain a superheated mixed raw material. After being heated to 175°C by preheater C, it enters the reactor and undergoes a continuous gas-phase catalytic ammonolysis reaction from top to bottom through the catalyst bed. The reaction effluent... The reactor outlet condenser cools the mixture to 25°C, causing tert-butylamine and unreacted methyl tert-butyl ether to condense into a liquid phase. Unreacted gaseous ammonia is separated into gas and liquid phases, then compressed and recycled. The condensed liquid product is washed in a water washing tower to remove dissolved ammonia, and then fed into a distillation column operating at atmospheric pressure. High-purity tert-butylamine is collected at the top of the column at 44°C, while unreacted methyl tert-butyl ether is collected at the bottom at 60°C and recycled back to the reactor inlet. The molar ratio of liquid ammonia to methyl tert-butyl ether is 5:1, the reaction temperature is 175°C, the reaction pressure is 2.0 MPa, and the mass hourly space velocity (WHSV) of methyl tert-butyl ether is 1.0 h⁻¹. -1 .

[0043] In Example 1, the conversion rate of methyl tert-butyl ether was 89.2%, the selectivity of tert-butylamine was 96.1%, the yield of tert-butylamine was 85.7%, and the purity of tert-butylamine was 99.5%.

[0044] Example 2 The preparation process for synthesizing tert-butylamine using methyl tert-butyl ether as described in Example 2 consists of the following steps: (1) Preparation of calcium alginate microspheres: Sodium alginate and starch were added to deionized water and stirred in a water bath at 40°C for 2 hours to obtain a composite solution. Then, the composite solution was added to a liquid paraffin-Span80 mixture and stirred at 800 r / min for 12 minutes to form an emulsion. 0.2 mol / L calcium chloride solution was added dropwise to the emulsion and stirred for another 30 minutes. The mixture was then crosslinked and cured at room temperature for 80 minutes. Finally, the microspheres were separated by centrifugation at 3000 r / min for 5 minutes and washed three times with deionized water to obtain wet calcium alginate gel microspheres. The wet calcium alginate gel microspheres were dried in a vacuum freeze dryer at -50°C for 24 hours until the mass of the microspheres no longer changed, thus obtaining semi-dry microspheres. The semi-dry microspheres were classified by an air classifier and microspheres with a particle size of 40-50 μm were obtained. (2) Preparation of SAPO precursor solution; (3) Composite crystallization: Microspheres with a particle size of 40-50 μm obtained in step (1) are directly added to the SAPO precursor solution prepared in step (2) for isothermal crystallization; (4) Preparation of SAPO-11 carrier by washing, drying and calcination; (5) Acid washing to remove calcium carbonate and water washing and drying to prepare ammonium-type SAPO-11 support; (6) Preparation of metal-supported catalysts by impregnation with active metals; (7) Activate the metal-supported catalyst to prepare an activated catalyst; (8) Tert-butylamine was prepared using methyl tert-butyl ether and liquid ammonia as raw materials under the catalysis of an activated catalyst.

[0045] In step (1), starch accounts for 15% of the mass of sodium alginate.

[0046] In step (1), the mass-volume ratio of sodium alginate to deionized water is 1.5:100, with units of g / mL.

[0047] The liquid paraffin-Span80 mixture mentioned in step (1) is made by adding Span80 (sorbitan monooleate) to liquid paraffin and stirring until completely dissolved. The mass-volume ratio of Span80 to liquid paraffin is 6:500, and the unit is g / mL.

[0048] In step (1), the volume ratio of the composite adhesive to the liquid paraffin-Span80 mixture is 1:5.

[0049] In step (1), the composite adhesive solution is added dropwise to the liquid paraffin-Span80 mixture, and the dropping speed is controlled at 3 mL / min.

[0050] The concentration of the calcium chloride solution in step (1) is 0.2 mol / L.

[0051] The semi-dry microspheres prepared in step (1) have a particle size of 40-50 μm after airflow classification. This uniform particle size ensures that the SAPO-11 precursor liquid can fully penetrate and form a mesoporous structure with concentrated pore size distribution after crystallization.

[0052] The preparation method of the SAPO precursor solution in step (2) is as follows: Boehmite is added to deionized water and stirred evenly. Then, phosphoric acid is added dropwise. After the addition is complete, stirring is continued for 1 hour until completely clear and transparent. Tetraethyl orthosilicate is added and stirring is continued for 1 hour until the tetraethyl orthosilicate is fully hydrolyzed. Finally, di-n-propylamine is added and stirring is continued for 1 hour until the gel is uniform. The gel is aged in a 90°C water bath for 24 hours to obtain the SAPO precursor solution. The mass ratio of boehmite to deionized water is 1:8. The content of calcined Al2O3 in boehmite is 68% by mass percentage. The mass concentration of phosphoric acid is 85%. Based on the Al2O3 in boehmite, the molar ratio of phosphoric acid to Al2O3 is controlled at 1.1:1. Based on the Al2O3 in boehmite, the molar ratio of tetraethyl orthosilicate to Al2O3 is controlled at 0.15:1. 1; Based on Al2O3 in pseudoboehmite, the molar ratio of di-n-propylamine to Al2O3 was controlled to be 2.0 : 1.

[0053] The specific steps of the composite crystallization in step (3) are as follows: the microspheres with a particle size of 40-50 μm prepared in step (1) are directly added to the SAPO precursor solution prepared in step (2), ultrasonically dispersed for 15 min, and then slowly stirred at room temperature for 2 h. After stopping the stirring, the mixture is transferred to a polytetrafluoroethylene-lined high-pressure reactor, heated to 180 °C at a rate of 1.5 °C / min, and crystallized at constant temperature under autogenous pressure for 30 h. Finally, it is naturally cooled to room temperature. The mass ratio of the microspheres with a particle size of 40-50 μm to the SAPO precursor solution is 1:8.

[0054] The preparation of SAPO-11 support by washing, drying and calcining in step (4) specifically involves discarding the supernatant, taking out the solid after isothermal crystallization, washing the obtained solid four times with deionized water until the pH of the washing solution is 7, drying it at 110℃ for 12 hours to obtain powder, placing the powder in a muffle furnace for calcination, and cooling it to room temperature with the furnace after calcination to obtain SAPO-11 support; wherein, the calcination is carried out in an air atmosphere, heating to 120℃ at a heating rate of 2℃ / min and holding for 1 hour, then heating to 300℃ at a heating rate of 2℃ / min and holding for 2 hours, and finally heating to 580℃ at a heating rate of 5℃ / min and holding for 4 hours.

[0055] The acid washing to remove calcium carbonate and the water washing and drying in step (5) are as follows: the SAPO-11 support is immersed in 0.1 mol / L hydrochloric acid and stirred at room temperature for 1 h. Then the solid is filtered out and immersed in 0.5 mol / L ammonium chloride solution. The solid is stirred at 80 °C for 2 h for separation and exchange. Then it is centrifuged and washed with deionized water until pH=7.0. Finally, it is dried at 110 °C for 12 h to prepare the ammonium type SAPO-11 support. The mass-volume ratio of solid to ammonium chloride is 1:10, and the unit is g / mL.

[0056] In step (5), hydrochloric acid is first used to remove most of the calcium carbonate and soluble calcium salts, and then ammonium chloride is added for ion exchange to remove the remaining Ca. 2+ Na + Cation exchange is equal to NH4 + .

[0057] In step (5), since the organic components of calcium alginate have been completely decomposed and transformed in the hydrothermal isothermal crystallization in step (3) and the high-temperature calcination in step (4), the obtained SAPO-11 support is mainly composed of an inorganic porous framework. Its molecular sieve structure can withstand dilute hydrochloric acid treatment to remove CaCO3 hard templates and soluble impurities. After ammonium exchange, a pure phase ammonium type SAPO-11 support is obtained.

[0058] The preparation of metal-supported catalyst by impregnation of active metal in step (6) is as follows: copper nitrate and zinc nitrate are dissolved in deionized water to prepare a mixed solution, and an ammonium-type SAPO-11 support is impregnated with an equal volume. After impregnation, the solution is aged at room temperature for 12 hours, and then dried and calcined to prepare the metal-supported catalyst. The drying temperature is 110℃, the drying time is 12 hours, the calcination atmosphere is air, the calcination temperature is 500℃, and the calcination time is 4 hours. In the prepared metal-supported catalyst, the mass of copper oxide accounts for 5.6% of the total mass of the catalyst, the mass of zinc oxide accounts for 3.6% of the total mass of the catalyst, and the mass of the ammonium-type SAPO-11 support accounts for 90.8% of the total mass of the catalyst.

[0059] The activation treatment of the metal-supported catalyst in step (7) to prepare the activated catalyst is specifically as follows: the metal-supported catalyst prepared in step (6) is loaded into a fixed-bed reactor, hydrogen atmosphere is introduced, the temperature is raised to 375℃ at a heating rate of 2℃ / min, and the temperature is kept constant for 3.6h. After the reduction is completed, the catalyst is cooled to 165℃ under hydrogen atmosphere to obtain the activated catalyst.

[0060] Analysis showed that the specific surface area of ​​the activated BET catalyst prepared in step (7) was 237 m². 2 / g, most probable pore size is 7.6nm, pore volume is 0.42cm³. 3 / g.

[0061] Step (8) describes the preparation of tert-butylamine using methyl tert-butyl ether and liquid ammonia as raw materials under the catalysis of an activated catalyst. Specifically, methyl tert-butyl ether is fed into preheating vaporizer A via a metering pump, and the vaporization temperature is controlled at 115°C to vaporize it into a gaseous phase. Liquid ammonia is fed into preheating vaporizer B via a metering pump, and converted into high-pressure superheated gaseous ammonia at 2.0 MPa and 145°C. The two materials are thoroughly mixed in a mixer to obtain a superheated mixed raw material. After being heated to 175°C by preheater C, it enters the reactor and undergoes a continuous gas-phase catalytic ammonolysis reaction from top to bottom through the catalyst bed. The reaction effluent... The reactor outlet condenser cools the mixture to 25°C, causing tert-butylamine and unreacted methyl tert-butyl ether to condense into a liquid phase. Unreacted gaseous ammonia is separated into gas and liquid phases, then compressed and recycled. The condensed liquid product is washed in a water washing tower to remove dissolved ammonia, and then fed into a distillation column operating at atmospheric pressure. High-purity tert-butylamine is collected at the top of the column at 44°C, while unreacted methyl tert-butyl ether is collected at the bottom at 60°C and recycled back to the reactor inlet. The molar ratio of liquid ammonia to methyl tert-butyl ether is 4:1, the reaction temperature is 175°C, the reaction pressure is 2.0 MPa, and the mass hourly space velocity (WHSV) of methyl tert-butyl ether is 1.0 h⁻¹. -1 .

[0062] In Example 2, the conversion rate of methyl tert-butyl ether was 84.5%, the selectivity of tert-butylamine was 97.2%, the yield of tert-butylamine was 82.1%, and the purity of tert-butylamine was 99.3%.

[0063] Example 3 The preparation process for synthesizing tert-butylamine using methyl tert-butyl ether as described in Example 3 consists of the following steps: (1) Preparation of calcium alginate microspheres: Sodium alginate and starch were added to deionized water and stirred in a water bath at 40°C for 2 hours to obtain a composite solution. Then, the composite solution was added to a liquid paraffin-Span80 mixture and stirred at 800 r / min for 12 minutes to form an emulsion. 0.2 mol / L calcium chloride solution was added dropwise to the emulsion and stirred for another 30 minutes. The mixture was then crosslinked and cured at room temperature for 80 minutes. Finally, the microspheres were separated by centrifugation at 3000 r / min for 5 minutes and washed three times with deionized water to obtain wet calcium alginate gel microspheres. The wet calcium alginate gel microspheres were dried in a vacuum freeze dryer at -50°C for 24 hours until the mass of the microspheres no longer changed, thus obtaining semi-dry microspheres. The semi-dry microspheres were classified by an air classifier and microspheres with a particle size of 40-50 μm were obtained. (2) Preparation of SAPO precursor solution; (3) Composite crystallization: Microspheres with a particle size of 40-50 μm obtained in step (1) are directly added to the SAPO precursor solution prepared in step (2) for isothermal crystallization; (4) Preparation of SAPO-11 carrier by washing, drying and calcination; (5) Acid washing to remove calcium carbonate and water washing and drying to prepare ammonium-type SAPO-11 support; (6) Preparation of metal-supported catalysts by impregnation with active metals; (7) Activate the metal-supported catalyst to prepare an activated catalyst; (8) Tert-butylamine was prepared using methyl tert-butyl ether and liquid ammonia as raw materials under the catalysis of an activated catalyst.

[0064] In step (1), starch accounts for 15% of the mass of sodium alginate.

[0065] In step (1), the mass-volume ratio of sodium alginate to deionized water is 1.5:100, with units of g / mL.

[0066] The liquid paraffin-Span80 mixture mentioned in step (1) is made by adding Span80 (sorbitan monooleate) to liquid paraffin and stirring until completely dissolved. The mass-volume ratio of Span80 to liquid paraffin is 6:500, and the unit is g / mL.

[0067] In step (1), the volume ratio of the composite adhesive to the liquid paraffin-Span80 mixture is 1:5.

[0068] In step (1), the composite adhesive solution is added dropwise to the liquid paraffin-Span80 mixture, and the dropping speed is controlled at 3 mL / min.

[0069] The concentration of the calcium chloride solution in step (1) is 0.2 mol / L.

[0070] The semi-dry microspheres prepared in step (1) have a particle size of 40-50 μm after airflow classification. This uniform particle size ensures that the SAPO-11 precursor liquid can fully penetrate and form a mesoporous structure with concentrated pore size distribution after crystallization.

[0071] The preparation method of the SAPO precursor solution in step (2) is as follows: Boehmite is added to deionized water and stirred evenly. Then, phosphoric acid is added dropwise. After the addition is complete, stirring is continued for 1 hour until completely clear and transparent. Tetraethyl orthosilicate is added and stirring is continued for 1 hour until the tetraethyl orthosilicate is fully hydrolyzed. Finally, di-n-propylamine is added and stirring is continued for 1 hour until the gel is uniform. The gel is aged in a 90°C water bath for 24 hours to obtain the SAPO precursor solution. The mass ratio of boehmite to deionized water is 1:8. The content of calcined Al2O3 in boehmite is 68% by mass percentage. The mass concentration of phosphoric acid is 85%. Based on the Al2O3 in boehmite, the molar ratio of phosphoric acid to Al2O3 is controlled at 1.1:1. Based on the Al2O3 in boehmite, the molar ratio of tetraethyl orthosilicate to Al2O3 is controlled at 0.15:1. 1; Based on Al2O3 in pseudoboehmite, the molar ratio of di-n-propylamine to Al2O3 was controlled to be 2.0 : 1.

[0072] The specific steps of the composite crystallization in step (3) are as follows: the microspheres with a particle size of 40-50 μm prepared in step (1) are directly added to the SAPO precursor solution prepared in step (2), ultrasonically dispersed for 15 min, and then slowly stirred at room temperature for 2 h. After stopping the stirring, the mixture is transferred to a high-pressure reactor lined with polytetrafluoroethylene, heated to 180 °C at a rate of 1.5 °C / min, and crystallized at constant temperature under autogenous pressure for 30 h. Finally, it is naturally cooled to room temperature. The mass ratio of the microspheres with a particle size of 40-50 μm to the SAPO precursor solution is 1:12.

[0073] The preparation of SAPO-11 support by washing, drying and calcining in step (4) specifically involves discarding the supernatant, taking out the solid after isothermal crystallization, washing the obtained solid five times with deionized water until the pH of the washing solution is 7, drying it at 110℃ for 12 hours to obtain powder, placing the powder in a muffle furnace for calcination, and cooling it to room temperature with the furnace after calcination to obtain SAPO-11 support; wherein, the calcination is carried out in an air atmosphere, heating to 120℃ at a heating rate of 2℃ / min and holding for 1 hour, then heating to 300℃ at a heating rate of 2℃ / min and holding for 2 hours, and finally heating to 580℃ at a heating rate of 5℃ / min and holding for 4 hours.

[0074] The acid washing to remove calcium carbonate and the water washing and drying in step (5) are as follows: the SAPO-11 support is immersed in 0.1 mol / L hydrochloric acid and stirred at room temperature for 1 h. Then the solid is filtered out and immersed in 0.5 mol / L ammonium chloride solution. The solid is stirred at 80 °C for 2 h for separation and exchange. Then it is centrifuged and washed with deionized water until pH=7.0. Finally, it is dried at 110 °C for 12 h to prepare the ammonium type SAPO-11 support. The mass-volume ratio of solid to ammonium chloride is 1:10, and the unit is g / mL.

[0075] In step (5), hydrochloric acid is first used to remove most of the calcium carbonate and soluble calcium salts, and then ammonium chloride is added for ion exchange to remove the remaining Ca. 2+ Na + Cation exchange is equal to NH4 + .

[0076] In step (5), since the organic components of calcium alginate have been completely decomposed and transformed in the hydrothermal isothermal crystallization in step (3) and the high-temperature calcination in step (4), the obtained SAPO-11 support is mainly composed of an inorganic porous framework. Its molecular sieve structure can withstand dilute hydrochloric acid treatment to remove CaCO3 hard templates and soluble impurities. After ammonium exchange, a pure phase ammonium type SAPO-11 support is obtained.

[0077] The preparation of metal-supported catalyst by impregnation of active metal in step (6) is as follows: copper nitrate and zinc nitrate are dissolved in deionized water to prepare a mixed solution, and an ammonium-type SAPO-11 support is impregnated with an equal volume. After impregnation, the solution is aged at room temperature for 12 hours, and then dried and calcined to prepare a metal-supported catalyst. The drying temperature is 110℃, the drying time is 12 hours, the calcination atmosphere is air, the calcination temperature is 500℃, and the calcination time is 4 hours. In the prepared metal-supported catalyst, the mass of copper oxide accounts for 5.7% of the total mass of the catalyst, the mass of zinc oxide accounts for 3.4% of the total mass of the catalyst, and the mass of the ammonium-type SAPO-11 support accounts for 90.9% of the total mass of the catalyst.

[0078] The activation treatment of the metal-supported catalyst in step (7) to prepare the activated catalyst is specifically as follows: the metal-supported catalyst prepared in step (6) is loaded into a fixed-bed reactor, hydrogen atmosphere is introduced, the temperature is raised to 370℃ at a heating rate of 2℃ / min, and the temperature is kept constant for 3.7h. After the reduction is completed, the temperature is cooled to 170℃ under hydrogen atmosphere to obtain the activated catalyst.

[0079] Analysis showed that the specific surface area of ​​the activated BET catalyst prepared in step (7) was 268 m². 2 / g, most probable pore size is 4.0nm, pore volume is 0.30cm³. 3 / g.

[0080] Step (8) describes the preparation of tert-butylamine using methyl tert-butyl ether and liquid ammonia as raw materials under the catalysis of an activated catalyst. Specifically, methyl tert-butyl ether is fed into preheating vaporizer A via a metering pump, and the vaporization temperature is controlled at 115°C to vaporize it into a gaseous phase. Liquid ammonia is fed into preheating vaporizer B via a metering pump, and converted into high-pressure superheated gaseous ammonia at 2.0 MPa and 145°C. The two materials are thoroughly mixed in a mixer to obtain a superheated mixed raw material. After being heated to 175°C by preheater C, it enters the reactor and undergoes a continuous gas-phase catalytic ammonolysis reaction from top to bottom through the catalyst bed. The reaction effluent... The reactor outlet condenser cools the mixture to 25°C, causing tert-butylamine and unreacted methyl tert-butyl ether to condense into a liquid phase. Unreacted gaseous ammonia is separated into gas and liquid phases, then compressed and recycled. The condensed liquid product is washed in a water washing tower to remove dissolved ammonia, and then fed into a distillation column operating at atmospheric pressure. High-purity tert-butylamine is collected at the top of the column at 44°C, while unreacted methyl tert-butyl ether is collected at the bottom at 60°C and recycled back to the reactor inlet. The molar ratio of liquid ammonia to methyl tert-butyl ether is 6:1, the reaction temperature is 175°C, the reaction pressure is 2.0 MPa, and the mass hourly space velocity (WHSV) of methyl tert-butyl ether is 1.0 h⁻¹. -1 .

[0081] In Example 3, the conversion rate of methyl tert-butyl ether was 91.5%, the selectivity of tert-butylamine was 94.8%, the yield of tert-butylamine was 86.8%, and the purity of tert-butylamine was 99.4%.

[0082] Comparative Example 1 The preparation process for synthesizing tert-butylamine using methyl tert-butyl ether described in Comparative Example 1 is the same as that in Example 1. The only difference is that only copper nitrate is impregnated in step 6. In the prepared metal-supported catalyst, the mass of copper oxide accounts for 5.5% of the total mass of the catalyst, and the mass of ammonium-type SAPO-11 support accounts for 94.5% of the total mass of the catalyst.

[0083] Analysis showed that the specific surface area of ​​the activated BET catalyst prepared in step (7) was 255 m². 2 / g, most probable pore size is 5.3nm, pore volume is 0.36cm³. 3 / g.

[0084] In Comparative Example 1, the conversion rate of methyl tert-butyl ether was 75.8%, the selectivity of tert-butylamine was 88.6%, the yield of tert-butylamine was 67.2%, and the purity of tert-butylamine was 98.2%.

[0085] Comparative Example 2 The preparation process for synthesizing tert-butylamine using methyl tert-butyl ether described in Comparative Example 2 is the same as that in Example 1. The only difference is that in step 6, only zinc nitrate is impregnated. In the prepared metal-supported catalyst, the mass of zinc oxide accounts for 3.5% of the total mass of the catalyst, and the mass of ammonium-type SAPO-11 support accounts for 96.5% of the total mass of the catalyst.

[0086] Analysis showed that the specific surface area of ​​the activated BET catalyst prepared in step (7) was 259 m². 2 / g, most probable pore size is 5.3nm, pore volume is 0.38cm³. 3 / g.

[0087] In Comparative Example 2, the conversion rate of methyl tert-butyl ether was 83.3%, the selectivity of tert-butylamine was 78.2%, the yield of tert-butylamine was 65.1%, and the purity of tert-butylamine was 98.0%.

[0088] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A preparation process for synthesizing tert-butylamine using methyl tert-butyl ether, characterized in that: It consists of the following steps: (1) Preparation of calcium alginate microspheres: Sodium alginate and starch were added to deionized water and stirred in a water bath at 40°C for 2 hours to obtain a composite solution. Then, the composite solution was added to a liquid paraffin-Span80 mixture and stirred at 800 r / min for 12 minutes to form an emulsion. 0.2 mol / L calcium chloride solution was added dropwise to the emulsion and stirred for another 30 minutes. The mixture was then crosslinked and cured at room temperature for 80 minutes. Finally, the microspheres were separated by centrifugation at 3000 r / min for 5 minutes and washed three times with deionized water to obtain wet calcium alginate gel microspheres. The wet calcium alginate gel microspheres were dried in a vacuum freeze dryer at -50°C for 24 hours until the mass of the microspheres no longer changed, thus obtaining semi-dry microspheres. The semi-dry microspheres were classified by an air classifier and microspheres with a particle size of 40-50 μm were obtained. (2) Preparation of SAPO precursor solution; (3) Composite crystallization: Microspheres with a particle size of 40-50 μm obtained in step (1) are directly added to the SAPO precursor solution prepared in step (2) for isothermal crystallization; (4) Preparation of SAPO-11 carrier by washing, drying and calcination; (5) Acid washing to remove calcium carbonate and water washing and drying to prepare ammonium-type SAPO-11 support; (6) Preparation of metal-supported catalysts by impregnation with active metals; (7) Activate the metal-supported catalyst to prepare an activated catalyst; (8) Tert-butylamine was prepared using methyl tert-butyl ether and liquid ammonia as raw materials under the catalysis of an activated catalyst.

2. The preparation process for synthesizing tert-butylamine using methyl tert-butyl ether according to claim 1, characterized in that: In step (1), starch accounts for 15% of the mass of sodium alginate; In step (1), the mass-volume ratio of sodium alginate to deionized water is 1.5:100, with units of g / mL. The liquid paraffin-Span80 mixture mentioned in step (1) is made by adding Span80 to liquid paraffin and stirring until completely dissolved. The mass-volume ratio of Span80 to liquid paraffin is 6:500, and the unit is g / mL. In step (1), the volume ratio of the composite adhesive to the liquid paraffin-Span80 mixture is 1:5; In step (1), the composite adhesive solution is added dropwise to the liquid paraffin-Span80 mixture, and the dropping speed is controlled at 3 mL / min; The concentration of the calcium chloride solution in step (1) is 0.2 mol / L.

3. The preparation process for synthesizing tert-butylamine using methyl tert-butyl ether according to claim 1, characterized in that: The preparation method of the SAPO precursor solution in step (2) is as follows: Boehmite is added to deionized water and stirred evenly. Then, phosphoric acid is added dropwise. After the addition is complete, stirring is continued for 1 hour until completely clear and transparent. Tetraethyl orthosilicate is added and stirring is continued for 1 hour until the tetraethyl orthosilicate is fully hydrolyzed. Finally, di-n-propylamine is added and stirring is continued for 1 hour until the gel is uniform. The gel is aged in a 90°C water bath for 24 hours to obtain the SAPO precursor solution. The mass ratio of boehmite to deionized water is 1:

8. The content of calcined Al2O3 in boehmite is 68% by mass percentage. The mass concentration of phosphoric acid is 85%. Based on the Al2O3 in boehmite, the molar ratio of phosphoric acid to Al2O3 is controlled at 1.1:

1. Based on the Al2O3 in boehmite, the molar ratio of tetraethyl orthosilicate to Al2O3 is controlled at 0.15:

1. 1; Based on Al2O3 in pseudoboehmite, the molar ratio of di-n-propylamine to Al2O3 was controlled to be 2.0:

1.

4. The preparation process for synthesizing tert-butylamine using methyl tert-butyl ether according to claim 1, characterized in that: The specific steps of the composite crystallization in step (3) are as follows: the microspheres with a particle size of 40-50 μm prepared in step (1) are directly added to the SAPO precursor solution prepared in step (2), ultrasonically dispersed for 15 min, stirred at room temperature for 2 h, and after stopping stirring, transferred to a polytetrafluoroethylene-lined high-pressure reactor, heated to 180 °C at a rate of 1.5 °C / min, and crystallized at constant temperature under autogenous pressure for 30 h, and finally naturally cooled to room temperature; wherein: the mass ratio of microspheres with a particle size of 40-50 μm to SAPO precursor solution is 1:8-12.

5. The preparation process for synthesizing tert-butylamine using methyl tert-butyl ether according to claim 1, characterized in that: The preparation of SAPO-11 support by washing, drying and calcining in step (4) specifically involves discarding the supernatant, taking out the solid after isothermal crystallization, washing the obtained solid with deionized water by centrifugation 4-5 times until the pH of the washing solution is 7, and then drying it at 110℃ for 12h to obtain powder. The powder is then placed in a muffle furnace for calcination. After calcination, the powder is cooled to room temperature with the furnace to obtain SAPO-11 support. The calcination is carried out in an air atmosphere, with the temperature increased to 120℃ at a heating rate of 2℃ / min and held for 1h, then increased to 300℃ at a heating rate of 2℃ / min and held for 2h, and finally increased to 580℃ at a heating rate of 5℃ / min and held for 4h.

6. The preparation process for synthesizing tert-butylamine using methyl tert-butyl ether according to claim 1, characterized in that: The acid washing to remove calcium carbonate and the water washing and drying in step (5) are as follows: the SAPO-11 support is immersed in 0.1 mol / L hydrochloric acid and stirred at room temperature for 1 h. Then the solid is filtered out and immersed in 0.5 mol / L ammonium chloride solution. The solid is stirred at 80 °C for 2 h for separation and exchange. Then it is centrifuged and washed with deionized water until pH=7.

0. Finally, it is dried at 110 °C for 12 h to prepare the ammonium type SAPO-11 support. The mass-volume ratio of solid to ammonium chloride is 1:10, and the unit is g / mL.

7. The preparation process for synthesizing tert-butylamine using methyl tert-butyl ether according to claim 1, characterized in that: The preparation of metal-supported catalyst by impregnation of active metal in step (6) is as follows: copper nitrate and zinc nitrate are dissolved in deionized water to prepare a mixed solution, and an ammonium-type SAPO-11 support is impregnated with an equal volume. After impregnation, the solution is aged at room temperature for 12 hours, and then dried and calcined to prepare the metal-supported catalyst. The drying temperature is 110℃, the drying time is 12 hours, the calcination atmosphere is air, the calcination temperature is 500℃, and the calcination time is 4 hours. In the prepared metal-supported catalyst, the mass of copper oxide accounts for 5.5-5.7% of the total mass of the catalyst, the mass of zinc oxide accounts for 3.4-3.6% of the total mass of the catalyst, and the mass of the ammonium-type SAPO-11 support accounts for 90.8-91.0% of the total mass of the catalyst.

8. The preparation process for synthesizing tert-butylamine using methyl tert-butyl ether according to claim 1, characterized in that: The activation treatment of the metal-supported catalyst in step (7) to prepare the activated catalyst is specifically as follows: the metal-supported catalyst prepared in step (6) is loaded into a fixed-bed reactor, hydrogen atmosphere is introduced, the temperature is raised to 365-375℃ at a heating rate of 2℃ / min, and the temperature is kept constant for 3.6-3.7h. After the reduction is completed, the catalyst is cooled to 165-170℃ in hydrogen atmosphere to obtain the activated catalyst.

9. The preparation process for synthesizing tert-butylamine using methyl tert-butyl ether according to claim 1, characterized in that: Step (8) describes the preparation of tert-butylamine using methyl tert-butyl ether and liquid ammonia as raw materials under the catalysis of an activated catalyst. Specifically, methyl tert-butyl ether is pumped into preheating vaporizer A via a metering pump, and the vaporization temperature is controlled at 115°C to vaporize it into a gaseous phase. Liquid ammonia is pumped into preheating vaporizer B via a metering pump, and converted into high-pressure superheated gaseous ammonia at 2.0 MPa and 145°C. The two materials are thoroughly mixed in a mixer to obtain a superheated mixed raw material. After being heated to 175°C by preheater C, it enters the reactor and undergoes a continuous gas-phase catalytic ammonolysis reaction from top to bottom through the catalyst bed. The reaction effluent is then processed through… The reactor outlet condenser cools the mixture to 25°C, causing tert-butylamine and unreacted methyl tert-butyl ether to condense into a liquid phase. Unreacted gaseous ammonia is separated into gas and liquid phases and then compressed and recycled. The condensed liquid product is then washed in a water washing tower to remove dissolved ammonia before being fed into a distillation column operating at atmospheric pressure. The column top temperature is controlled at 44°C to collect high-purity tert-butylamine, while the column bottom temperature is controlled at 60°C to collect unreacted methyl tert-butyl ether, which is recycled back to the reactor inlet. The molar ratio of liquid ammonia to methyl tert-butyl ether is 4-6:1, the reaction temperature is 175°C, the reaction pressure is 2.0 MPa, and the mass hourly space velocity (WHSV) of methyl tert-butyl ether is 1.0 h⁻¹. -1 .