阅读说明：本技术 一种改进的四甲基碳酸氢铵制备方法 (Improved preparation method of tetramethyl ammonium bicarbonate ) 是由 刘颂军 孙炜 冯亚楠 吕国文 于 2021-09-29 设计创作，主要内容包括：公开了一种改进的四甲基碳酸氢铵制备方法,以碳酸二甲酯和三甲胺水溶液为反应原料,采用一步法制备四甲基碳酸氢铵；其中,反应在有机胺改性的分子筛存在下进行。由于加入了特定比例的有机胺改性的分子筛,产品收率进一步提高。有机胺改性的分子筛与碳酸二甲酯或其产物产生了相互作用,降低了最终产品发生副反应的概率。(An improved process for preparing tetramethyl ammonium hydrogen carbonate is disclosed, which uses dimethyl carbonate and aqueous solution of trimethylamine as reaction raw materials, and adopts one-step method to prepare tetramethyl ammonium hydrogen carbonate; wherein the reaction is carried out in the presence of an organic amine modified molecular sieve. The product yield is further improved due to the addition of the organic amine modified molecular sieve in a specific proportion. The organic amine modified molecular sieve interacts with the dimethyl carbonate or the product thereof, and the probability of side reaction of the final product is reduced.)

1. An improved preparation method of tetramethyl ammonium bicarbonate, which takes dimethyl carbonate and trimethylamine aqueous solution as reaction raw materials and adopts a one-step method to prepare the tetramethyl ammonium bicarbonate; the method is characterized in that the reaction is carried out in the presence of an organic amine modified molecular sieve.

2. The preparation method of the invention is characterized in that the molecular sieve is selected from one or more of SBA-3, SBA-15, SBA-16, MCM-41 and MCM-48; preferably, the molecular sieve is selected from SBA-15.

3. The preparation method of the invention, wherein the BET surface area of the molecular sieve is 500-700m²(ii)/g; the average pore diameter is 6-12 nm; the average grain diameter is 0.5-4 μm; the space group is a hexagonal system; preferably, the molecular sieve has a BET surface area of 550-650m²(ii)/g; the average pore diameter is 7-10 nm; the average grain diameter is 1-2 μm; the space group is a hexagonal system.

4. The preparation method of the invention is characterized in that the organic amine is selected from NH₂-(CH₂)_n-Si(OEt)₃(ii) a n is 1-10; preferably, the organic amine is selected from NH₂-(CH₂)₃-Si(OEt)₃。

5. The preparation method comprises the following steps of: mixing the components in a weight ratio of (4-6): the molecular sieve of 1 and organic amine are refluxed and reacted for 6 to 32 hours in toluene; filtering, washing and drying; preferably, the modification method of the organic amine modified molecular sieve is as follows: mixing the following components in percentage by weight of 5: the molecular sieve of 1 and organic amine are refluxed and reacted for 12 hours in toluene; filtering, washing and drying.

6. The preparation method provided by the invention is characterized in that the molar ratio of dimethyl carbonate to trimethylamine is 1: (0.8-1.5); preferably, the molar ratio of dimethyl carbonate to trimethylamine is 1: (1.0-1.2).

7. According to the preparation method, the addition amount of the organic amine modified molecular sieve is 8-14 wt% of dimethyl carbonate; preferably, the organic amine modified molecular sieve is added in an amount of 11 wt% of the dimethyl carbonate.

8. The preparation method comprises the following steps of (1) enabling the mass fraction of the trimethylamine aqueous solution to be 25-40 wt%; preferably, the mass fraction of the trimethylamine aqueous solution is 33 wt%.

9. The preparation method of the invention is characterized in that the reaction is carried out in a nitrogen atmosphere, and the pressure is 1.0-1.5 MPa; preferably, the reaction is carried out in a nitrogen atmosphere at a pressure of 1.2 MPa.

10. The preparation method provided by the invention is characterized in that the reaction temperature is 100-110 ℃, and the reaction time is 2-10 h; preferably, the reaction temperature is 105 ℃ and the reaction time is 5 h.

Technical Field

The invention relates to an improved preparation method of tetramethyl ammonium bicarbonate, belonging to the technical field of organic synthesis.

Background

Tetramethylammonium bicarbonate is a key raw material for preparing tetramethylammonium hydroxide by ion membrane electrolysis, which has wide applications in a variety of fields including, but not limited to, catalysts, surfactants, templating agents, organic synthesis reagents, and the like. In particular, in recent years, high purity tetramethylammonium hydroxide has been used as a cationic developer in large scale integrated circuits and as a cleaning agent in microelectronic chips, both to reduce the impurity ion content and to reduce the cost. Therefore, the research on the preparation method of tetramethylammonium bicarbonate is a precondition for preparing high-purity tetramethylammonium hydroxide.

Chinese patent application publication CN101314572A discloses a method for preparing tetramethylammonium bicarbonate by a tubular reactor condensation reaction, comprising: mixing and preheating raw materials dimethyl carbonate (DMC) and Trimethylamine (TMA) with a solvent according to a molar ratio of 0.5-1.5: 1, introducing the mixture into a tubular reactor for condensation reaction to prepare tetramethyl ammonium bicarbonate, and recovering the solvent after the reaction for recycling. The method adopts continuous tubular reaction, can effectively solve the defects of intermittent kettle type reaction, has simple and compact equipment, small occupied area, investment saving, high use efficiency, stable product quality, simple and concise production process control, and can improve the safety factor of the equipment to a great extent and effectively reduce the consumption and the cost.

Chinese patent application publication CN107417539A discloses a method for synthesizing tetramethylammonium bicarbonate by a kettle-type reactor series tubular reactor; synthesizing the electrolytic raw material tetramethyl ammonium bicarbonate of tetramethyl ammonium hydroxide by a kettle type reactor and a tubular reactor in series. Pumping raw materials of dimethyl carbonate, trimethylamine and methanol as a solvent into a reaction kettle by a pump, heating materials to reaction temperature by using reaction heat for reaction, removing redundant reaction heat through a cooler, pressing the materials into a subsequent tubular reactor for continuous reaction through pressure generated by a reaction system, feeding the materials discharged from the tubular reactor into a two-stage falling-film evaporator, recovering the solvent and unconverted raw materials of the reaction system in the first-stage falling-film evaporator, performing methyl carbonate tetramethyl ammonium hydrolysis reaction in the second-stage falling-film evaporator, and simultaneously performing evaporation and recovery of the methanol generated by the reaction. The invention has the advantages of low operation pressure, simple synthesis method and equipment, small occupied area, low power consumption, investment saving, continuous production and stable product quality.

Chinese patent application publication CN107281994A discloses a device and method for continuously preparing tetramethylammonium bicarbonate by circulating tubular reactors in series; raw materials of dimethyl carbonate, trimethylamine and solvent methanol continuously enter a circulating tank through a feeding pump, the mixed materials are pumped into a tubular reactor together with materials overflowing from the circulating tubular reactor through a circulating pump, the dimethyl carbonate and the trimethylamine react in the solvent methanol on the tube pass of the reactor, reaction heat released in the reaction process is taken away through a cooling medium in the shell pass, most of the materials circulate, a small part of the materials enter the tubular reactor for continuous reaction through the pressure generated by a reaction system, and the reacted materials enter a falling film evaporator for recycling a methanol solvent and extracting a tetramethylammonium bicarbonate product. The reaction system of the invention has low operation pressure, most of the conversion reaction is carried out in the circulating tubular reactor, and the reaction heat can be used for generating low-pressure steam; the whole set of equipment can be used for continuous production, and the product quality is stable.

Zhouyu et al first use methanol to absorb trimethylamine, to make methanol solution of trimethylamine; then taking a certain amount of trimethylamine solution and dimethyl carbonate to react in a high-pressure reaction kettle, and finding out the optimal reaction condition for synthesizing TMAMC by investigating the reaction temperature, the material ratio and the initial nitrogen pressure: the reaction temperature is 120 ℃; the material ratio n-trimethylamine to n-dimethyl carbonate is 1.1: 1; the initial nitrogen pressure is 0.1 MPa; the reaction took 2h to complete under these conditions. The yield of TMAMC can reach 98.4%.

Further, Zhang Gui Ju et al further synthesized tetramethylammonium bicarbonate from dimethyl carbonate and trimethylamine aqueous solution, and mainly examined the influence of raw material molar ratio, reaction temperature and reaction time on product yield. When the molar ratio of dimethyl carbonate to trimethylamine is 1: 1.2, the reaction temperature is 105 ℃, and the reaction time is 5 hours, the yield of the tetramethyl ammonium bicarbonate is 93.0 percent.

However, in the above prior art, chinese patent application publication CN101314572A has technical drawbacks of high trimethylamine partial pressure and high equipment energy consumption; the Chinese patent application publications CN107417539A and CN107281994A have the technical defects of large reactor volume and complex device; the method of Zhouyu Lu and the like adopts a two-step method, and the method of Zhang Gui Ju and the like adopts a one-step method; the former step is complicated, and the hydrolysis reaction is easy to reduce the product yield; the latter procedure is simple, but the product yield is still unsatisfactory.

Therefore, there is still a need to provide an improved method for preparing tetramethylammonium bicarbonate, which addresses the above-mentioned drawbacks of the prior art.

Disclosure of Invention

The invention aims to provide an improved preparation method of tetramethylammonium bicarbonate. Compared with the prior art, the preparation method further improves the product yield.

In order to realize the aim, the invention provides an improved preparation method of tetramethylammonium bicarbonate, which takes dimethyl carbonate and trimethylamine aqueous solution as reaction raw materials and adopts a one-step method to prepare the tetramethylammonium bicarbonate; the method is characterized in that the reaction is carried out in the presence of an organic amine modified molecular sieve.

The preparation method of the invention is characterized in that the molecular sieve is selected from one or more of SBA-3, SBA-15, SBA-16, MCM-41 and MCM-48.

Preferably, the molecular sieve is selected from SBA-15.

The preparation method of the invention, wherein the BET surface area of the molecular sieve is 500-700m²(ii)/g; the average pore diameter is 6-12 nm; the average grain diameter is 0.5-4 μm; the space group is a hexagonal system.

Preferably, the molecular sieve has a BET surface area of 550-650m²(ii)/g; the average pore diameter is 7-10 nm; the average grain diameter is 1-2 μm; the space group is a hexagonal system.

The preparation method of the invention is characterized in that the organic amine is selected from NH₂-(CH₂)_n-Si(OEt)₃；n＝1-10。

Preferably, the organic amine is selected from NH₂-(CH₂)₃-Si(OEt)₃。

The preparation method comprises the following steps of: mixing the components in a weight ratio of (4-6): the molecular sieve of 1 and organic amine are refluxed and reacted for 6 to 32 hours in toluene; filtering, washing and drying.

Preferably, the modification method of the organic amine modified molecular sieve is as follows: mixing the following components in percentage by weight of 5: the molecular sieve of 1 and organic amine are refluxed and reacted for 12 hours in toluene; filtering, washing and drying.

The preparation method provided by the invention is characterized in that the molar ratio of dimethyl carbonate to trimethylamine is 1: (0.8-1.5).

Preferably, the molar ratio of dimethyl carbonate to trimethylamine is 1: (1.0-1.2).

According to the preparation method, the addition amount of the organic amine modified molecular sieve is 8-14 wt% of dimethyl carbonate.

Preferably, the organic amine modified molecular sieve is added in an amount of 11 wt% of the dimethyl carbonate.

The preparation method provided by the invention is characterized in that the mass fraction of the trimethylamine aqueous solution is 25-40 wt%.

Preferably, the mass fraction of the trimethylamine aqueous solution is 33 wt%.

The preparation method of the invention is characterized in that the reaction is carried out in a nitrogen atmosphere, and the pressure is 1.0-1.5 MPa.

Preferably, the reaction is carried out in a nitrogen atmosphere at a pressure of 1.2 MPa.

The preparation method of the invention comprises the steps of reacting at the temperature of 100 ℃ and 110 ℃ for 2-10 h.

Preferably, the reaction temperature is 105 ℃ and the reaction time is 5 h.

The inventors have found that the improved tetramethylammonium bicarbonate preparation method according to the present invention further improves the product yield by adding a specific ratio of organic amine modified molecular sieve. Without wishing to be bound by any theory, the organic amine modified molecular sieve interacts with the dimethyl carbonate or its products, reducing the probability of side reactions in the final product.

Detailed Description

The invention will be further illustrated with reference to specific embodiments.

It should be understood that the detailed description of the invention is merely illustrative of the spirit and principles of the invention and is not intended to limit the scope of the invention. Furthermore, it should be understood that various changes, substitutions, deletions, modifications or adjustments may be made by those skilled in the art after reading the disclosure of the present invention, and such equivalents are also within the scope of the invention as defined in the appended claims.

In the present invention, the SBA-15 molecular sieve is purchased from Juna New energy Co., Tezhou, Jiangsu.

The relevant indexes are as follows:

BET surface area (m)²/g)：600；

Average pore diameter (nm): 7-10;

average particle diameter (μm): 1-2;

space group: a hexagonal system.

Example 1

2g of SBA-15 molecular sieve is added into 30mL of anhydrous toluene, 0.8g of 3-aminopropyltriethoxysilane is added into the anhydrous toluene, and the reflux reaction is carried out for 12 hours at the temperature of 108 ℃. And after the reaction is finished, filtering, washing for 3 times by using anhydrous toluene, drying for 24 hours at the temperature of 120 ℃, and cooling to room temperature to obtain the organic amine modified SBA-15 molecular sieve.

Example 2

9.0g (0.1mol) of dimethyl carbonate and 17.9g (containing 0.1mol) of trimethylamine aqueous solution with the mass fraction of 33 percent are added into an autoclave; then 1.0g of the organic amine modified SBA-15 molecular sieve of example 1 was added. And (4) introducing nitrogen, checking the air tightness of the high-pressure reaction kettle, emptying and pressurizing to 1.2 MPa. Turning on the heater and the stirrer, raising the temperature to 105 ℃, and stirring for reaction for 5 hours. And after the reaction is finished, reducing the pressure, cooling and filtering to remove the organic amine modified SBA-15 molecular sieve. And distilling under reduced pressure to remove a small amount of by-product methanol to obtain the aqueous solution of tetramethyl ammonium bicarbonate. And (4) concentrating the aqueous solution, and drying to obtain a white solid, namely the product.

Example 3

9.0g (0.1mol) of dimethyl carbonate and 21.5g (containing 0.12mol) of trimethylamine aqueous solution with the mass fraction of 33 percent are added into an autoclave; then 1.0g of the organic amine modified SBA-15 molecular sieve of example 1 was added. And (4) introducing nitrogen, checking the air tightness of the high-pressure reaction kettle, emptying and pressurizing to 1.2 MPa. Turning on the heater and the stirrer, raising the temperature to 105 ℃, and stirring for reaction for 5 hours. And after the reaction is finished, reducing the pressure, cooling and filtering to remove the organic amine modified SBA-15 molecular sieve. And distilling under reduced pressure to remove a small amount of by-product methanol to obtain the aqueous solution of tetramethyl ammonium bicarbonate. And (4) concentrating the aqueous solution, and drying to obtain a white solid, namely the product.

Samples were taken and analyzed by HPLC for product yields of examples 2 and 3, which were 94.1% and 96.3%, respectively.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention shall fall within the protection scope of the present invention.