Production method for high-purity tetrapropylammonium hydroxide and high-purity quaternary ammonium base produced thereby

Abstract

A production method for high-purity tetrapropylammonium hydroxide, comprising the following steps: adding tetrapropylammonium halide into a raw material chamber of an electrolytic cell; and by means of electrolysis, tetrapropylammonium cations passing through a cationic membrane, entering a cathode chamber, and being combined with hydroxide ions generated at a cathode, so as to form tetrapropylammonium hydroxide to prepare a quaternary ammonium base. The raw material chamber contains a citrate ion compound. The production method for high-purity tetrapropylammonium hydroxide has the advantage of helping to improve the quality of a quaternary ammonium base product.

Description

Production method of high-purity tetrapropylammonium hydroxide and high-purity quaternary ammonium base produced by the method TECHNICAL FIELD

[0001] The present application relates to the technical field of high-purity organic quaternary ammonium base production, in particular to a production method of high-purity tetrapropylammonium hydroxide and high-purity quaternary ammonium base produced by the method. BACKGROUND

[0002] Tetrapropylammonium hydroxide is a quaternary ammonium base compound and has important applications in many fields. Main uses include: 1. used as a molecular sieve template: tetrapropylammonium hydroxide can be used to synthesize TS-1 molecular sieve, which can be used as a catalyst for the green catalytic oxidation process of caprolactam and propylene oxide; 2. polymerization catalyst for silicone products: tetrapropylammonium hydroxide is used as a catalyst in the polymerization process of silicone rubber and other silicone products, and can also be used for the synthesis of polycarbonates; 3. phase transfer catalyst: in organic synthesis chemistry, tetrapropylammonium hydroxide is also used as a phase transfer catalyst to accelerate the speed of chemical reactions and improve product selectivity; 4. pharmaceutical and cosmetic industries: the emulsifying, bactericidal and preservative properties of tetrapropylammonium hydroxide make it widely used in the pharmaceutical and cosmetic industries, such as emulsifiers, bactericides and preservatives.

[0003] Tetrapropylammonium hydroxide has a wide range of applications, and there are more and more researches on the production process of tetrapropylammonium hydroxide. With the development of the communication industry, tetrapropylammonium hydroxide is gradually applied to chip cleaning and other industries in addition to traditional industrial fields.

[0004] Tetrapropylammonium hydroxide has high requirements for product purity for chip cleaning, and there are differences in requirements for different grades. G1 grade generally requires metal ions to be less than 100 ppb, and G2 grade generally requires metal ions to be less than 10 ppb. The production methods of tetrapropylammonium hydroxide mainly include ion exchange method, calcium hydroxide hydrolysis method and electrolysis method; among these methods, the product produced by electrolysis method has better quality, but there is still a certain gap with the requirements for chip cleaning. SUMMARY

[0005] In order to improve the quality of tetrapropylammonium hydroxide, the present application provides a production method of high-purity tetrapropylammonium hydroxide and high-purity quaternary ammonium base produced by the method.

[0006] In a first aspect, the present application provides a production method of high-purity tetrapropylammonium hydroxide, which adopts the following technical solution:

[0007] The application discloses a production method of high-purity tetrapropyl ammonium hydroxide, which comprises the following steps: adding tetrapropyl ammonium halide into a raw material chamber of an electrolytic cell, preparing quaternary ammonium base by electrolysis, and making tetrapropyl ammonium cations enter a cathode chamber through a cation membrane to combine with hydroxyl ions generated by the cathode to form tetrapropyl ammonium hydroxide; and the raw material chamber contains a citrate ion compound.

[0008] By adopting the technical scheme, the tetrapropyl ammonium hydroxide is prepared by electrolysis, tetrapropyl ammonium cations enter the cathode chamber through the cation membrane to combine with hydroxyl ions in the cathode chamber to form tetrapropyl ammonium hydroxide. When the cations pass through the cation membrane, metal ions in the raw material chamber compete with the tetrapropyl ammonium cations; by adding the compound containing citrate ions, the citrate ions combine with the metal ions in the raw material chamber, the competitiveness of the metal ions is weakened, the tetrapropyl ammonium cations better pass through the cation membrane to enter the cathode chamber, the probability of the metal ions passing through the cation membrane to enter the cathode chamber is reduced, the content of the metal ions in the product is reduced, and the product quality is improved.

[0009] Preferably, the concentration of the citrate ions in the raw material chamber is 40 ppm-120 ppm, and more preferably, the concentration of the citrate ions in the raw material chamber is 60 ppm-90 ppm.

[0010] By adopting the technical scheme, the metal ion content is reduced by adopting the appropriate concentration of the citrate ions, and the product quality is improved.

[0011] Preferably, the electrolytic cell comprises an anode chamber, a raw material chamber and a cathode chamber which are sequentially adjacent; an anode plate is arranged in the anode chamber, a cathode plate is arranged in the cathode chamber, and the anode plate is connected with the cathode plate through a power supply; the anode chamber is communicated with the raw material chamber through a negative ion membrane, and the raw material chamber is communicated with the cathode chamber through a cation membrane.

[0012] By adopting the technical scheme, the tetrapropyl ammonium hydroxide is prepared by using a three-chamber two-membrane electrolysis method, the negative ion membrane is arranged between the anode chamber and the raw material chamber, the metal ions belong to cations and cannot pass through the negative ion membrane, the probability of the metal ions in the anode chamber entering the raw material chamber is reduced, the probability of the metal ions entering the cathode chamber is reduced, and the product quality is improved.

[0013] Preferably, the raw material chamber contains tripropyl amine.

[0014] By adopting the technical scheme, a small amount of tripropyl amine is contained in the raw material chamber, the tripropyl amine has a certain complexation with the metal ions, the probability of the metal ions passing through the cation membrane is reduced, and the product quality is improved. The inventors have found in experiments that the citric acid and the tripropyl amine have a certain synergistic effect, and the product quality is better improved.

[0015] Preferably, the mass concentration of tripropylamine in the raw material chamber is 300-600 ppm; the concentration of tetrapropylammonium cation in the raw material chamber is 10%-14%.

[0016] By using the above technical solution, the electrolysis is carried out by selecting more optimal contents of tripropylamine and tetrapropylammonium cation, which is beneficial to further reduce the content of metal ions and improve product quality.

[0017] Preferably, the citrate ion compound is citric acid or ammonium citrate.

[0018] By using the above technical solution, citric acid and ammonium citrate are used as the source of citrate ions, and ammonium ions can be removed by reduced pressure distillation after electrolysis, which helps to avoid the introduction of additional impurities and improve product quality.

[0019] Preferably, the citrate ion compound is citric acid.

[0020] By using the above technical solution, citric acid is used as the source of citrate ions, which helps to improve product quality.

[0021] Preferably, the tetrapropylammonium halide is tetrapropylammonium bromide.

[0022] By using the above technical solution, tetrapropylammonium bromide is used as the raw material to prepare tetrapropylammonium hydroxide by electrolysis, which helps to reduce costs.

[0023] In the second aspect, the application provides a high-purity quaternary ammonium base, which is prepared by the above method for producing high-purity tetrapropylammonium hydroxide.

[0024] By using the above technical solution, tetrapropylammonium hydroxide is prepared by the method disclosed in the application, which helps to reduce the content of impurities and improve product quality.

[0025] In summary, the application has at least one of the following beneficial technical effects:

[0026] The application produces tetrapropylammonium hydroxide by electrolysis, and citric acid is added to the raw material chamber to react with metal ions, weaken the competition between metal ions and tetrapropylammonium cations, and reduce the probability of metal ions passing through the cation membrane, which helps to reduce impurities in the product and improve product quality.

[0027] The application has tripropylamine and citrate ions in the raw material chamber in the electrolysis process, the tripropylamine and citrate ions have synergistic effect, which helps to reduce the content of metal ions in the product and improve the product quality.

[0028] In the application, the concentration of tripropylamine and citrate ions in the raw material chamber has certain influence on the metal ions in the product, and by controlling the concentration of tripropylamine and citrate ions, the product quality can be improved. BRIEF DESCRIPTION OF DRAWINGS

[0029] Fig. 1 is a schematic view of the structure of the electrolytic cell used in the application.

[0030] Reference signs: 1, anode chamber; 2, raw material chamber; 3, cathode chamber; 4, anode plate; 5, cathode plate; 6, anion membrane; 7, cation membrane. DETAILED DESCRIPTION

[0031] The commonly used tetrapropylammonium hydroxide production process generally uses tetrapropylammonium bromide as raw material, and electrolytic cell is used to prepare tetrapropylammonium hydroxide by electrolysis. The commonly used electrolytic cell generally includes a raw material chamber and a cathode chamber, the raw material chamber and the cathode chamber are communicated through a cation membrane, and a cathode plate is installed in the cathode chamber; in the electrolysis process, water in the cathode chamber is electrolyzed to form hydrogen and hydroxide ions, the hydrogen leaves the electrolytic cell in the form of gas, and the tetrapropylammonium cation combines with the hydroxide ion through the cation membrane to form tetrapropylammonium hydroxide. The inventors found in practice that in the electrolysis process, the metal ions in the raw material compete with the tetrapropylammonium cation, and a part of the metal ions will pass through the cation membrane into the cathode chamber, resulting in a small amount of metal ions in the tetrapropylammonium hydroxide product, which affects the product quality.

[0032] Based on the above technical background, the application proposes a technical solution, a small amount of citric acid is added to the raw material chamber of the electrolytic machine, which reacts with the metal ions, reduces the competition between the metal ions and the tetrapropylammonium cation, and more tetrapropylammonium cations pass through the cation membrane and fewer metal ions pass through the cation membrane, so that the content of metal ions in the product is reduced, which is beneficial to improve the product quality. A small amount of tripropylamine is added to the raw material chamber, and the tripropylamine and citric acid have certain synergistic effect, which further reduces the content of metal ions in the product. In addition, the concentration of tripropylamine and tetrapropylammonium cation in the raw material chamber needs to be in a suitable proportion, which is beneficial to better improve the product quality.

[0033] During the electrolysis process, the contents of citric acid and tripropylamine in the raw material chamber are detected, and citric acid and tripropylamine are added according to the detection results, so that the contents of citric acid and tripropylamine in the raw material chamber are kept within the required range. In actual production, as the electrolysis time is prolonged, a small amount of solid substances such as precipitates or flocs will adhere to the inner wall of the raw material chamber; therefore, the electrolysis machine needs to be cleaned regularly, such as once a month, which will help to maintain the stability of product quality. During the electrolysis process, the concentration of bromide ions in the raw material chamber is detected, and the concentration of tetrapropylammonium cations in the raw material chamber is calculated, and tetrapropylammonium bromide aqueous solution is added to keep the concentration of tetrapropylammonium cations in the raw material chamber within the required range.

[0034] The specific embodiments are described below.

[0035] The water used in the following examples is deionized water with a conductivity of not more than 20 μs / cm. The power source for the electrolysis process is a direct current power source. The mass concentration of tetrapropylammonium cations in the raw material chamber during the electrolysis process is not more than 14%, preferably 10-14%. During the electrolysis process, the concentration of bromide ions in the raw material chamber is titrated with silver nitrate, and the concentration of tetrapropylammonium cations is measured by conversion, and the concentration of tetrapropylammonium cations in the raw material chamber during the electrolysis process is tracked; according to the change of the concentration of tetrapropylammonium cations in the raw material chamber, tetrapropylammonium bromide aqueous solution is added to the raw material chamber during the electrolysis process to keep the mass concentration of tetrapropylammonium cations in the raw material chamber at 10-14%. The concentration of tetrapropylammonium cations in the added tetrapropylammonium bromide aqueous solution is 36%, and water will be added to the raw material chamber at the start to keep the concentration of tetrapropylammonium cations in the raw material chamber at 10-14%. The concentration of citrate ions is detected by ion chromatography, the concentration of tripropylamine is detected by headspace chromatography, and the concentration of metal ions is detected by ICP-MS. The same set of electrolysis equipment is used in the following examples. Before starting the power source to begin electrolysis, the electrolytic cell contains water.

[0036] The application is further described in detail below with reference to the accompanying drawings. Example

[0037] Example 1: A method for producing high-purity tetrapropylammonium hydroxide, comprising the following steps:

[0038] Take 5 kg of tetrapropyl ammonium bromide, and prepare a tetrapropyl ammonium bromide aqueous solution with a tetrapropyl ammonium cation mass concentration of 36% by adding pure water. Take the tetrapropyl ammonium bromide aqueous solution, add it to the raw material chamber 2 of the electrolytic cell, dilute it with water to a tetrapropyl ammonium bromide mass concentration of 12% in the raw material chamber 2, and add citric acid to make the citrate ion concentration about 40 ppm. The electrolytic cell comprises anode chamber 1, raw material chamber 2 and cathode chamber 3 in sequence; an anode plate 4 is installed in the anode chamber 1, a cathode plate 5 is installed in the cathode chamber 3, and the anode plate 4 and the cathode plate 5 are connected by a power supply; the anode chamber 1 and the raw material chamber 2 are communicated by an anion membrane 6, and the raw material chamber 2 and the cathode chamber 3 are communicated by a cation membrane 7; water is added to the anode chamber 1 and the cathode chamber 3 before the electrolysis is started; first, the tetrapropyl ammonium bromide aqueous solution is added to the raw material chamber 2, and through electrolysis, the tetrapropyl ammonium cation passes through the cation membrane 7 into the cathode chamber 3, and combines with the hydroxide ion generated by the cathode to form tetrapropyl ammonium hydroxide.

[0039] During the electrolysis process, the materials in the anode chamber 1, the raw material chamber 2 and the cathode chamber 3 are circulated by circulating pumps respectively, and the circulation flow rates of the materials in the anode chamber 1 and the cathode chamber 3 are both 80 ml / min, and the circulation flow rate of the material in the raw material chamber 2 is 150 ml / min. According to the concentration change of tetrapropyl ammonium bromide in the raw material chamber 2, tetrapropyl ammonium bromide aqueous solution is added to the raw material chamber 2 during the electrolysis process to keep the concentration of tetrapropyl ammonium bromide in the raw material chamber 2 at about 12%, and citric acid aqueous solution is added every 4 hours to keep the concentration of citrate ion at about 40 ppm. When the electrolysis is carried out for 24 hours, the concentration of tetrapropyl ammonium hydroxide product in the cathode chamber 3 increases to about 25%, and water is added to the cathode chamber 3 to keep the concentration at about 25%, and 1 kg of product is discharged from the cathode chamber 3 every 8 hours, and the electrolysis is carried out for 48 hours, and the content of metal ions in the product generated when the electrolysis is carried out for 48 hours is detected. Example

[0040] The difference between Example 2 and Example 1 is that 300 ppm of tripropylamine is added to the raw material chamber of Example 2, and the content of tripropylamine in the raw material chamber is detected by headspace chromatography every 4 hours during the electrolysis process, and tripropylamine is added according to the detection result to keep the content of tripropylamine in the raw material chamber at about 300 ppm, and the others are the same as in Example 1. Example

[0041] The difference between Example 3 and Example 2 is that no citric acid is added to the raw material chamber of Example 3, and the others are the same as in Example 2. Example

[0042] The difference between Example 4 and Example 2 is that the concentration of tetrapropyl ammonium cation in the raw material chamber of Example 4 is 6%-8%, and the others are the same as in Example 2. Example

[0043] Example 5 is different from Example 2 in that the concentration of citrate ions in the raw material chamber of Example 5 is 90 ppm, and the other conditions are the same as those of Example 2.

[0044] Examples 6-10

[0045] Examples 6-10 are different from Example 5 in that the concentrations of citrate ions and tripropylamine in the raw material chamber of Examples 6-10 are different, and the other conditions are the same as those of Example 5. The concentrations of the components in the raw material chamber of Examples 6-10 are shown in Table 1.

[0046] Table 1: Molar ratio of each raw material in Examples 6-10

[0047] Comparative Example 1

[0048] Comparative Example 1 is different from Example 1 in that no citric acid is added in Comparative Example 1, and the other conditions are the same as those of Example 1.

[0049] Table 2: Comparison of the content of metal ions in the product after electrolysis for 48 h

[0050] Comparative Example 1 is prepared by a conventional electrolysis method, and the content of iron ions, chromium ions, calcium ions, etc. in the obtained product is in the range of 35-45 ppb. The electrolysis process of Example 1 contains citric acid in the raw material chamber, and the content of iron ions and chromium ions in the product obtained by electrolysis is significantly reduced. By comparing the experimental results of Example 1 and Comparative Example 1, it can be seen that in the preparation process of tetrapropylammonium hydroxide, the addition of citrate ions interacts with metal ions, reduces the probability of metal ions entering the product chamber through the cation membrane, and is beneficial to reducing the impurity content in the product and improving the product quality.

[0051] By comparing the experimental results of Example 1 and Example 2, the content of iron ions and chromium ions is further reduced in the raw material chamber of Example 2 by simultaneously adding tripropylamine and citric acid, and the content of calcium ions and copper ions is also significantly reduced. The effect is not obvious in Example 3 without the addition of citric acid but only with the addition of tripropylamine, and the effect is more obvious when tripropylamine is used simultaneously with citric acid. In Example 4, the concentration of tetrapropylammonium cations is not in the optimal range, and the effect is not optimal.

[0052] By comparing the experimental results of Example 2 and Example 5, the concentrations of citric acid and tripropylamine in the raw material chamber of Example 5 are appropriate, the concentration of tetrapropylammonium cations is appropriate, the metal ion content of the prepared product is low, the content of iron ions, chromium ions, copper ions and calcium ions is less than 10 ppb, and the product quality is high. In Examples 6-7, although the amount of citric acid is appropriate, the concentration of tripropylamine is not in the optimal range, and the metal ion content is slightly increased. In Examples 8-10, the amount of citric acid is appropriate, the concentration of tripropylamine is appropriate, the metal ion content of the prepared product is low, and the product quality is high.

[0053] The embodiments of the present application are preferred embodiments of the present application, and are not intended to limit the protection scope of the present application, and thus: any equivalent changes made according to the structure, shape, principle of the present application should be covered within the protection scope of the present application.

Claims

1. A method for producing high-purity tetrapropylammonium hydroxide, characterized by, The method comprises the following steps: adding tetrapropyl ammonium halide into a raw material chamber of an electrolytic cell, through electrolysis, the tetrapropyl ammonium cation enters a cathode chamber through a cation membrane, combines with the hydroxide ion generated by the cathode to form tetrapropyl ammonium hydroxide, and the quaternary ammonium base is prepared; the raw material chamber contains citrate ion compound.

2. The method of claim 1, wherein the method is characterized by: The concentration of citrate ion in the raw material chamber is 40-120 ppm.

3. The method of claim 1, wherein the method is characterized by: The electrolytic cell comprises an anode chamber (1), a raw material chamber (2) and a cathode chamber (3) in sequence; an anode plate (4) is installed in the anode chamber (1), a cathode plate (5) is installed in the cathode chamber (3), the anode plate (4) is connected with the cathode plate (5) through a power supply; the anode chamber (1) and the raw material chamber (2) are communicated through an anion membrane (6), and the raw material chamber (2) and the cathode chamber (3) are communicated through a cation membrane (7).

4. The method of claim 1, wherein the method is characterized by: The raw material chamber contains tripropylamine.

5. The method for producing high-purity tetrapropylammonium hydroxide according to claim 4, characterized in that: The mass concentration of tripropylamine in the raw material chamber is 300-600 ppm, and the concentration of tetrapropyl ammonium cation in the raw material chamber is 10%-14%.

6. The method for producing high-purity tetrapropylammonium hydroxide according to claim 1, characterized in that: The citrate ion compound is citric acid or ammonium citrate.

7. The method for producing high-purity tetrapropylammonium hydroxide according to claim 6, characterized in that: The citrate ion compound is citric acid.

8. The method for producing high-purity tetrapropylammonium hydroxide according to claim 1, characterized in that: The tetrapropyl ammonium halide is tetrapropyl ammonium bromide.

9. A high purity quaternary ammonium base, characterized in that: The method is prepared by the method for producing high-purity tetrapropyl ammonium hydroxide according to any one of claims 1-8.

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