A solid catalyst for synthesizing tetramethylammonium bicarbonate and its preparation method and application

Abstract

The invention discloses a solid catalyst for synthesizing tetramethylammonium bicarbonate and a preparation method and application thereof, the method comprising the following steps: a, mixing a cerium salt solution and an organic base through a supergravity reactor; separating the solid after mixing to obtain a Ce precursor; b, the Ce precursor is optionally immersed in a tetramethylammonium hydroxide aqueous solution with a mass concentration of 2-25%, surface modification, and then freeze-drying and / or supercritical drying the filtrate to obtain CeO nanoparticles; c, mixing the CeO nanoparticles with a cyclopentadienyl cobalt metal catalyst in a solvent, stirring and treating at 40-80°C for 5-12h, separating and drying, and obtaining a CpCo-CeO catalyst with a surface chemical bond. The solid catalyst is applied to the one-step synthesis of tetramethylammonium bicarbonate, has the advantages of high product selectivity and high conversion rate, and can improve the product yield.

Description

Technical Field

[0001] The invention relates to a catalyst and an organic synthesis method, in particular to a solid catalyst for synthesizing tetramethylammonium bicarbonate and a preparation method and application thereof. Background Art

[0002] Tetramethylammonium bicarbonate (TMAC) is the raw material for the electrolytic preparation of tetramethylammonium hydroxide (TMAH). TMAH is an important organic strong base, mainly used in the preparation of cleaning agents and etchants in the electronics industry, so electronic grade purity is usually required. Studying the synthesis process of TMAC is of great significance to reducing the production cost of the TMAH industry chain and improving product grades.

[0003] The traditional preparation process of TMAC is: dimethyl carbonate (DMC) and trimethylamine are methylated to produce tetramethylammonium carbonate, and then hydrolyzed to obtain TMAC. Trimethylamine is a gas at room temperature and is usually stored and used in the form of an aqueous solution or an alcohol solution. Currently, literature reports mostly use a methanol solution of trimethylamine as a raw material to prepare tetramethylammonium bicarbonate through a two-step reaction of methylation and hydrolysis. There are also many studies that combine the above two steps into one step, that is, directly use water as a solvent to allow the methylation reaction and the hydrolysis reaction to proceed simultaneously, but in an alkaline reaction system, DMC will undergo significant hydrolysis, resulting in a low product yield.

[0004] Patent CN113735713A proposes the use of a molecular sieve catalyst modified with an organic amine to synthesize TMAC in a one-step process in an aqueous solution, but the maximum yield is 96%, and the use of the molecular sieve will greatly introduce metal ions, which is not conducive to the application of the product in the field of electronic chemicals.

[0005] In summary, the existing process for synthesizing TMAC by a one-step method still cannot achieve satisfactory results in terms of product yield. In view of the above-mentioned defects of the prior art, the present invention provides an improved TMAC catalyst and a preparation method. Summary of the invention

[0006] In order to solve the above technical problems, the present invention provides a solid catalyst for synthesizing tetramethylammonium bicarbonate and a preparation method and application thereof.

[0007] Based on the first aspect of the present invention, the present invention provides a method for preparing a solid catalyst for synthesizing tetramethylammonium bicarbonate.

[0008] Based on the second aspect of the present invention, the present invention also provides a solid catalyst for synthesizing tetramethylammonium bicarbonate prepared by the above method.

[0009] Based on the third aspect of the present invention, the present invention also provides an application of synthesizing tetramethylammonium bicarbonate under the action of the above catalyst.

[0010] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0011] First, a method for preparing a solid catalyst for synthesizing tetramethylammonium bicarbonate comprises the following steps:

[0012] a. mixing a cerium salt solution and an organic base through a supergravity reactor; separating the solid after mixing to obtain a Ce precursor;

[0013] b. The Ce precursor is optionally immersed in a tetramethylammonium hydroxide aqueous solution with a mass concentration of 2-25%, preferably 8-12%, to modify the surface, and then the filtrate is freeze-dried and / or supercritically dried to obtain CeO 2 Nanoparticles; when the organic base in step a does not contain tetramethylammonium hydroxide, surface modification is indispensable; by surface modification with tetramethylammonium hydroxide, impurities generated by the application of the catalyst in a strong base system can be reduced, and quaternary ammonium base sites can be generated to enhance the catalytic effect;

[0014] c. CeO 2 The nanoparticles are mixed with a cyclopentadienyl cobalt metal catalyst in a solvent, stirred at 40-80°C for 5-12 hours, separated and dried to obtain CpCo-CeO with a surface chemical bond. 2 Catalyst. The construction of CpCo- chemical bonds can regulate the surface electron density of Ce, increase the reaction activation energy, and improve product selectivity.

[0015] In some examples, in step a, the molar ratio of the cerium salt to the organic base is 1:(1-10);

[0016] Preferably, the organic base is aqueous ammonia and / or tetramethylammonium hydroxide.

[0017] Preferably, the cerium salt is one or more of cerium nitrate, cerium sulfate, cerium trichloride and hydrates thereof.

[0018] In some examples, in step a, the mixing conditions of the supergravity reactor are: supergravity level 150-2000G, preferably 300-800G (1G represents 1 surface gravity acceleration, corresponding to 9.8N / kg, 100G means 100 times the gravity effect), residence time is 2-30min, preferably 5-10min.

[0019] In some examples, in step b, the surface modification temperature is 40-80°C, preferably 60-70°C, and the time is 4-8h, preferably 5-7h.

[0020] In some examples, in step b, the freeze-drying conditions are: treating at -70°C to -30°C for 24-72h, preferably treating at -50°C to -40°C for 36-48h; and / or,

[0021] Supercritical drying conditions: supercritical CO 2 It is the drying medium, the drying pressure is 10-15MPa, the drying temperature is 35-45℃, and the drying time is 10-20min.

[0022] In some examples, the CeO prepared in step b 2 The particle size of nanoparticles is 0.1-2nm.

[0023] In some examples, in step c, CeO 2 The ratio of the nanoparticles to the cyclopentadienyl cobalt metal catalyst is 0.1-10 based on the molar ratio of Ce to Co;

[0024] Preferably, the cyclopentadienyl cobalt metal catalyst is selected from at least one of dicarbonyl cyclopentadienyl cobalt, cyclopentadienyl (dimethyl fumarate) (triethylphosphite) cobalt (I);

[0025] Preferably, the solvent in step c is any one or more of water, acetone, methanol, ethanol, acetonitrile, tetrahydrofuran, dichloromethane, and chloroform.

[0026] Secondly, a solid catalyst for synthesizing tetramethylammonium bicarbonate prepared by the method described above.

[0027] Again, an application of a solid catalyst for synthesizing tetramethylammonium bicarbonate prepared by the method described above, characterized in that the solid catalyst is used to catalyze the reaction of an aqueous solution of dimethyl carbonate and trimethylamine to prepare tetramethylammonium bicarbonate.

[0028] In some examples, the molar ratio of dimethyl carbonate to trimethylamine is 1:(0.5-2);

[0029] Preferably, the amount of the solid catalyst is 1-10% of the mass of dimethyl carbonate;

[0030] Preferably, the reaction temperature is 100-150° C., the reaction pressure is 0-1 MPa, and the reaction time is 3-6 h.

[0031] The solid catalyst provided by the present invention is applied to the one-step synthesis of tetramethylammonium bicarbonate, has the advantages of high product selectivity and high conversion rate, and the yield is as high as more than 97%. Compared with the prior art, it has obvious advantages. It is speculated that the possible reaction mechanism includes the decomposition and resynthesis reaction process of DMC, thereby realizing material circulation and maintaining a high product yield. DETAILED DESCRIPTION

[0032] The present invention is further described below by means of specific examples. The examples described in the present invention are only used to illustrate the present invention and do not limit the scope of the present invention.

[0033] In the present invention, unless otherwise specified, the raw materials and equipment used can be purchased from the market or are commonly used in the art. Dicarbonyl cyclopentadienyl cobalt (95%) was purchased from Aladdin Cobalt, brand D166511; cyclopentadienyl (dimethyl fumarate) (triethylphosphinate) cobalt (I) was purchased from Aladdin, brand C405499.

[0034] The methods in the embodiments, unless otherwise specified, are conventional methods in the art.

[0035] [Example 1]

[0036] Solid catalyst A was prepared according to the following steps:

[0037] a. The cerium nitrate hexahydrate solution (0.2 mol / L) and the tetramethylammonium hydroxide solution (0.4 mol / L) were fed into a supergravity reactor at a volume ratio of 1:2, and mixed under the conditions of supergravity level of 150G and residence time of 2 min; after mixing, the solid was separated by centrifugation to obtain a Ce precursor;

[0038] b. The Ce precursor was immersed in a 2% tetramethylammonium hydroxide aqueous solution, modified at 40°C for 4 hours, filtered and freeze-dried at -70°C for 24 hours to obtain CeO with a particle size of 2 nm. 2 Nanoparticles;

[0039] c. CeO with a Ce / Co molar ratio of 0.1 2 The nanoparticles were mixed with dicarbonyl cyclopentadienyl cobalt in water, stirred at 40 °C for 5 h, separated and dried to obtain CpCo-CeO with surface chemical bonds. 2 catalyst.

[0040] [Example 2]

[0041] Solid catalyst B was prepared by the following steps:

[0042] a. The cerium nitrate hexahydrate solution (1 mol / L) and ammonia water (2 mol / L) were introduced into a supergravity reactor at a volume ratio of 1:0.5, and mixed under the conditions of supergravity level of 2000G and residence time of 30min; after mixing, the solid was separated by centrifugation to obtain a Ce precursor;

[0043] b. The Ce precursor was immersed in a 25% tetramethylammonium hydroxide aqueous solution, modified at 80°C for 8 hours, filtered and freeze-dried at -30°C for 72 hours to obtain CeO with a particle size of 2 nm. 2 Nanoparticles;

[0044] c. CeO with a Ce / Co molar ratio of 10 2 The nanoparticles were mixed with cyclopentadienyl (dimethyl fumarate) (triethylphosphinate) cobalt (I) in methanol, stirred at 80 °C for 12 h, separated and dried to obtain CpCo-CeO with surface chemical bonds. 2 catalyst.

[0045] [Example 3]

[0046] The solid catalyst C was prepared by the following steps:

[0047] a. The cerium nitrate hexahydrate solution (0.5 mol / L) and the tetramethylammonium hydroxide solution (5 mol / L) were fed into a supergravity reactor at a volume ratio of 1:1, and mixed under the conditions of a supergravity level of 1000G and a residence time of 20 min; after mixing, the solid was separated by centrifugation to obtain a Ce precursor;

[0048] b. The Ce precursor was immersed in a 12% tetramethylammonium hydroxide aqueous solution, modified at 60°C for 6 hours, filtered, freeze-dried at -50°C for 48 hours, and obtained CeO with a particle size of 0.1 nm. 2 Nanoparticles;

[0049] c. CeO with a Ce / Co molar ratio of 2 2 The nanoparticles were mixed with cyclopentadienyl (dimethyl fumarate) (triethylphosphinate) cobalt (I) in ethanol, stirred at 60 °C for 8 h, separated and dried to obtain CpCo-CeO with surface chemical bonds. 2 catalyst.

[0050] [Example 4]

[0051] The solid catalyst D was prepared by the following steps:

[0052] a. The cerium nitrate hexahydrate solution (0.8 mol / L) and ammonia water (0.8 mol / L) were fed into a supergravity reactor at a volume ratio of 1:2, and mixed under the conditions of supergravity level of 300G and residence time of 10 min; after mixing, the solid was separated by centrifugation to obtain a Ce precursor;

[0053] b. The Ce precursor was immersed in a tetramethylammonium hydroxide aqueous solution with a mass concentration of 8%, modified at 50°C for 5 hours, filtered and freeze-dried at -40°C for 36 hours to obtain CeO with a particle size of 0.5 nm.2 Nanoparticles;

[0054] c. CeO with a Ce / Co molar ratio of 2 2 The nanoparticles were mixed with cyclopentadienyl (dimethyl fumarate) (triethylphosphinate) cobalt (I) in acetone, stirred at 50 °C for 6 h, separated and dried to obtain CpCo-CeO with surface chemical bonds. 2 catalyst.

[0055] [Example 5]

[0056] The solid catalyst E was prepared according to the following steps:

[0057] a. The cerium nitrate hexahydrate solution (0.8 mol / L) and the tetramethylammonium hydroxide solution (1.6 mol / L) were fed into a supergravity reactor at a volume ratio of 1:3, and mixed under the conditions of supergravity level of 1500G and residence time of 25 min; after mixing, the solid was separated by centrifugation to obtain a Ce precursor;

[0058] b. The Ce precursor was immersed in a 20% tetramethylammonium hydroxide aqueous solution, modified at 70°C for 7h, filtered and freeze-dried at -60°C for 30h to obtain CeO with a particle size of 0.4nm. 2 Nanoparticles;

[0059] c. CeO with a Ce / Co molar ratio of 8 2 The nanoparticles were mixed with dicarbonyl cyclopentadienyl cobalt in water, stirred at 70 °C for 6 h, separated and dried to obtain CpCo-CeO with surface chemical bonds. 2 catalyst.

[0060] [Example 6]

[0061] The solid catalyst F was prepared as follows:

[0062] a. The cerium nitrate hexahydrate solution (0.3 mol / L) and the tetramethylammonium hydroxide solution (0.3 mol / L) were fed into a supergravity reactor at a volume ratio of 1:3, and mixed under the conditions of supergravity level of 500G and residence time of 5 min; after mixing, the solid was separated by centrifugation to obtain a Ce precursor;

[0063] b. The Ce precursor was immersed in a tetramethylammonium hydroxide aqueous solution with a mass concentration of 18%, and modified at 50°C for 7 hours. After filtration, it was freeze-dried at -50°C for 60 hours to obtain CeO with a particle size of 1 nm. 2 Nanoparticles;

[0064] c. CeO with a Ce / Co molar ratio of 5 2The nanoparticles were mixed with dicarbonyl cyclopentadienyl cobalt in ethanol, stirred at 70 °C for 10 h, separated and dried to obtain CpCo-CeO with surface chemical bonds. 2 catalyst.

[0065] [Example 7]

[0066] The solid catalyst G was prepared by the following steps:

[0067] a. The cerium nitrate hexahydrate solution (0.6 mol / L) and the tetramethylammonium hydroxide solution (1.2 mol / L) were fed into a supergravity reactor at a volume ratio of 1:4, and mixed under the conditions of supergravity level of 1700G and residence time of 15 min; after mixing, the solid was separated by centrifugation to obtain a Ce precursor;

[0068] b. Freeze-dry the Ce precursor at -60 °C for 70 h to obtain CeO with a particle size of 1.2 nm. 2 Nanoparticles;

[0069] c. CeO with a Ce / Co molar ratio of 3 2 The nanoparticles were mixed with dicarbonyl cyclopentadienyl cobalt in methanol, stirred at 70 °C for 7 h, separated and dried to obtain CpCo-CeO with surface chemical bonds. 2 catalyst.

[0070] [Comparative Example 1]

[0071] The Ce precursor was prepared according to step a in Example 2 and was directly recorded as solid catalyst H.

[0072] [Comparative Example 2]

[0073] The solid catalyst was prepared in the same manner as in Example 2, except that step c was omitted and the CeO 2 The nanoparticles are directly recorded as solid catalyst I.

[0074] [Comparative Example 3]

[0075] Solid catalyst J was prepared in substantially the same manner as in Example 2, except that the modification in step b was not performed, and the Ce precursor prepared in step a was directly mixed with cyclopentadienyl(dimethylfumarate)(triethylphosphinate)cobalt(I) complex to carry out the reaction in step c.

[0076] [Comparative Example 4]

[0077] Solid catalyst K was prepared in substantially the same manner as in Example 2, except that the freeze-drying conditions in step b were modified to the following drying conditions: drying at a pressure of 50 kPa and a temperature of 60° C. for 4 h.

[0078] [Comparative Example 5]

[0079] Cyclopentadienyl(dimethylfumarate)(triethylphosphite)cobalt(I) was directly referred to as solid catalyst L.

[0080] [Application Example 1-7, Comparative Application Example 1-6]

[0081] Different solid catalysts were used to synthesize TMAC through a one-step reaction:

[0082] Add dimethyl carbonate and a catalyst to a reactor, the catalyst dosage is 2 wt % of dimethyl carbonate, heat to 120°C, add an aqueous solution of trimethylamine (the mass ratio of water to trimethylamine is 7:3), the molar ratio of trimethylamine to dimethyl carbonate is 1:1, and sample test after timed reaction for 5 hours.

[0083] The reaction results are shown in Table 1:

[0084] Table 1. Performance test results in application examples 1-7 and comparative application examples 1-6

[0085]

[0086] The above is only a preferred embodiment of the present invention. It should be pointed out that ordinary technicians in this field can make several improvements and supplements without departing from the method of the present invention. These improvements and supplements should also be regarded as the scope of protection of the present invention.

Claims

1. A method for preparing a solid catalyst for synthesizing tetramethylammonium bicarbonate, characterized in that: The following steps are involved: a. mixing a cerium salt solution and ammonia water and / or tetramethylammonium hydroxide through a supergravity reactor; separating the solid after mixing to obtain a Ce precursor; b. The Ce precursor is optionally immersed in a tetramethylammonium hydroxide aqueous solution with a mass concentration of 2-25% for surface modification, and then the filtrate is freeze-dried and / or supercritically dried to obtain CeO2 nanoparticles; when tetramethylammonium hydroxide is not contained in step a, surface modification is indispensable; c. Mixing CeO2 nanoparticles and cyclopentadienyl cobalt metal catalyst in a solvent, stirring and treating at 40-80°C for 5-12 hours, separating and drying, and obtaining a CpCo-CeO2 catalyst with a chemical bond constructed on the surface; The cyclopentadienyl cobalt metal catalyst is selected from at least one of dicarbonyl cyclopentadienyl cobalt and cyclopentadienyl (dimethyl fumarate) (triethylphosphite) cobalt (I).

2. The method for preparing a solid catalyst for synthesizing tetramethylammonium bicarbonate according to claim 1, wherein In step b, the Ce precursor is optionally immersed in an aqueous solution of tetramethylammonium hydroxide with a mass concentration of 8-12% for surface modification.

3. The method for preparing a solid catalyst for synthesizing tetramethylammonium bicarbonate according to claim 1, wherein In step a, the molar ratio of the cerium salt to ammonia water and / or tetramethylammonium hydroxide is 1:(1-10).

4. The method for preparing a solid catalyst for synthesizing tetramethylammonium bicarbonate according to claim 3, wherein: In step a, the mixing conditions of the high gravity reactor are: high gravity level 150-2000G, residence time 2-30min.

5. The method for preparing a solid catalyst for synthesizing tetramethylammonium bicarbonate according to claim 4, wherein: In step a, the mixing conditions of the high gravity reactor are: high gravity level 300-800G, residence time 5-10min.

6. The method for preparing a solid catalyst for synthesizing tetramethylammonium bicarbonate according to any one of claims 1 to 5, characterized in that: In step b, the surface modification temperature is 40-80° C. and the time is 4-8 hours.

7. The method for preparing a solid catalyst for synthesizing tetramethylammonium bicarbonate according to claim 6, wherein: In step b, the surface modification temperature is 60-70° C. and the time is 5-7 hours.

8. The method for preparing a solid catalyst for synthesizing tetramethylammonium bicarbonate according to claim 6, wherein: In step b, freeze-drying conditions are: treatment at -70°C to -30°C for 24-72h; and / or, The supercritical drying conditions are: supercritical CO2 as the drying medium, drying pressure of 10-15MPa, drying temperature of 35-45℃, and drying time of 10-20min.

9. The method for preparing a solid catalyst for synthesizing tetramethylammonium bicarbonate according to claim 8, characterized in that: In step b, the freeze-drying conditions are: treating at -50°C to -40°C for 36-48h.

10. The method for preparing a solid catalyst for synthesizing tetramethylammonium bicarbonate according to claim 8, characterized in that: The particle size of the CeO2 nanoparticles prepared in step b is 0.1-2nm.

11. The method for preparing a solid catalyst for synthesizing tetramethylammonium bicarbonate according to any one of claims 1 to 5, characterized in that: In step c, the usage ratio of CeO2 nanoparticles to cyclopentadienyl cobalt metal catalyst is 0.1-10 based on the molar ratio of Ce to Co.

12. The method for preparing a solid catalyst for synthesizing tetramethylammonium bicarbonate according to claim 11, characterized in that: The solvent in step c is any one or more of water, acetone, methanol, ethanol, acetonitrile, tetrahydrofuran, dichloromethane and chloroform.

13. A solid catalyst for synthesizing tetramethylammonium bicarbonate prepared by the method described in any one of claims 1 to 12.

14. Use of a solid catalyst for synthesizing tetramethylammonium bicarbonate prepared by the method according to any one of claims 1 to 12, characterized in that: The solid catalyst is used for catalyzing the reaction of dimethyl carbonate and trimethylamine in aqueous solution to prepare tetramethylammonium bicarbonate.

15. The use according to claim 14, characterized in that: The molar ratio of dimethyl carbonate to trimethylamine is 1:(0.5-2).

16. The use according to claim 15, characterized in that The usage of the solid catalyst is 1-10% of the mass of dimethyl carbonate.

17. The use according to claim 15, characterized in that: The reaction temperature is 100-150°C, the reaction pressure is 0-1MPa, and the reaction time is 3-6h.

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