A preparation method of electronic grade guanidine salt

Abstract

The present invention provides a method for preparing an electronic-grade guanidine salt, comprising: (1) preparing a guanidine salt aqueous solution using ultrapure water; (2) adding an antisolvent to the guanidine salt aqueous solution to obtain a moist precipitate; and (3) drying the precipitate to obtain an electronic-grade guanidine salt. The preparation method provided by the present invention is simple to operate and has a high recovery rate; is carried out at room temperature, is safe and reliable, and does not pose any safety hazards; has low raw material prices, and can effectively reduce production costs; and has a high purity product, wherein the purity of the obtained guanidine salt can reach a content of >99.5% and a metal ion content of <1 ppm.

Description

Technical Field

[0001] The present invention relates to the field of chemical industry, and in particular to a method for preparing an electronic grade guanidine salt Background Art

[0002] Recrystallization is a purification process that is simple to operate and has low equipment costs. Recrystallization utilizes solubility differences at different temperatures. For example, CN105523998A discloses a process for preparing methimazole, which uses methanol, ethanol, isopropanol and other solvents to recrystallize methimazole by heating and cooling, ultimately obtaining a product with an HPLC purity of >99% and a common metal ion content of <1ppm. CN110606820A uses a mixture of toluene, ethanol, and water in proportion as a crystallization solvent to recrystallize N-ethylcarbazole. The resulting final product has an impurity content of less than 0.1% and a metal ion content of less than 100ppm. However, the alcohol used is a low-flash point solvent (flash point <15°C), and the temperature during operation is relatively high (>50°C), posing a potential safety hazard. CN1850590A discloses a method for producing electronic-grade phosphoric acid. By using a gradient cooling method, electronic-grade phosphoric acid with a total metal ion content of no more than 0.6ppm can be obtained, but the production process requires strict control and efficiency still needs to be improved. CN101781185A discloses a method for removing metal ions in the synthesis of polyhydroxybenzophenone. The metal ions are reduced by adding a metal ion chelating agent during the recrystallization process. The metal ion content of the product is reduced to below 100 ppb. However, the added metal ion chelating agent is inevitably encapsulated in the product, resulting in low product purity.

[0003] Similarly, recrystallization can also utilize the difference in solubility in different solvents, that is, anti-solvent recrystallization. After the anti-solvent is added, the material to be purified is rapidly supersaturated and precipitated. This method is often used in drug purification, such as the purification method of terephthalaldehyde mentioned in CN101006044A, which ultimately obtains a product with a purity of >99.6%. The method for purifying urapidil by anti-solvent recrystallization mentioned in CN102267951A ultimately obtains a product with a purity of >99.82%. CN108272867A mentions a process for producing high-purity buckwheat flavonoids by an anti-solvent crystallization method, the purity of which can reach more than 99%, and the yield can reach more than 94%. However, these patents do not disclose the metal ion concentration.

[0004] Because guanidine salts significantly inhibit the corrosion of certain metals, they are essential components in semiconductor cleaning and polishing fluids. For example, they are an essential component in chemical mechanical polishing fluids such as those described in CN101970595A and CN103834306A. They also play a crucial role in cleaning fluids for plasma etching residues, such as those described in CN102051281A, CN101657531A, and CN102827708A.

[0005] Currently, there are no patents for the preparation of electronic-grade guanidine salts. Guanidine salts, such as guanidine nitrate, are oxidizing and toxic, and can decompose and explode at high temperatures. Therefore, the use of a heating-and-cooling recrystallization method presents potential safety risks, especially when using the low-flash-point alcohols mentioned in the aforementioned patents as solvents. Therefore, obtaining guanidine salts with acceptable metal ion content and a simple process at room temperature has become an urgent challenge in the field. Summary of the Invention

[0006] To solve the above problems, the present invention provides a method for preparing an electronic-grade guanidine salt, which is purified by recrystallization using an anti-solvent method in one step to obtain a guanidine salt with a content of >99.5% and a metal ion content of <1 ppm. The method is simple to operate and has a high yield. At the same time, all steps are performed at room temperature, which is safe.

[0007] Specifically, the present invention provides a method for preparing an electronic-grade guanidine salt, comprising the following steps:

[0008] (1) preparing a guanidine salt aqueous solution using ultrapure water;

[0009] (2) adding an antisolvent to the guanidine salt aqueous solution to obtain a moist precipitate;

[0010] (3) drying the precipitate to obtain an electronic grade guanidine salt.

[0011] Preferably, the guanidine salt aqueous solution is a saturated guanidine salt aqueous solution.

[0012] Preferably, the preparation of the guanidine salt aqueous solution includes filtering insoluble matter in the guanidine salt aqueous solution.

[0013] Preferably, the anti-solvent is a water-soluble organic solvent.

[0014] Preferably, the water-soluble organic solvent is alcohol, ketone or ether.

[0015] Preferably, the mass ratio of the anti-solvent to the guanidine salt aqueous solution is 0.01:1 to 10:1.

[0016] Preferably, the step (3) comprises washing the wet precipitate again with an anti-solvent.

[0017] Preferably, the metal ion content in the anti-solvent is less than 1 ppm.

[0018] Compared with the prior art, the advantages of the present invention are: the preparation method provided by the present invention is simple to operate and has a high recovery rate; it is carried out at room temperature, is safe and reliable, and does not pose any safety hazards; the raw materials are inexpensive, which can effectively reduce production costs; the obtained product is high in purity, and the purity of the obtained guanidine salt can reach a content of >99.5% and a metal ion content of <1ppm. DETAILED DESCRIPTION

[0019] The advantages of the present invention are described in detail below with reference to specific embodiments.

[0020] Example 1:

[0021] (1) Add 3 kg of guanidine carbonate to 7 kg of ultrapure water, stir until completely dissolved, and then filter to obtain a 30% guanidine carbonate aqueous solution;

[0022] (2) adding 14 kg of methanol, causing guanidine carbonate to be supersaturated and precipitated to obtain a wet guanidine carbonate material;

[0023] (3) The wet guanidine carbonate is washed with methanol and then dried to obtain electronic grade guanidine carbonate.

[0024] Example 2:

[0025] (1) Add 1.5 kg of guanidine phosphate to 8.5 kg of ultrapure water, stir until completely dissolved, and then filter to obtain a 10% aqueous solution of guanidine nitrate;

[0026] (2) adding 1.0 kg of ethanol, guanidine nitrate is supersaturated and separated to obtain guanidine phosphate wet material;

[0027] (3) The wet guanidine phosphate is washed with acetone and then dried to obtain electronic grade guanidine phosphate.

[0028] Example 3:

[0029] (1) Add 1 kg of guanidine acetate to 9 kg of ultrapure water, stir until completely dissolved, and then filter to obtain a 10% guanidine acetate aqueous solution;

[0030] (2) adding 15 kg of isopropyl alcohol, causing guanidine nitrate to be supersaturated and precipitated to obtain a wet guanidine nitrate material;

[0031] (3) The wet guanidine nitrate is washed with methanol and then dried to obtain electronic grade guanidine acetate.

[0032] Example 4:

[0033] (1) Add 1 kg of guanidine nitrate to 9 kg of ultrapure water, stir until completely dissolved, and then filter to obtain a 10% guanidine nitrate aqueous solution;

[0034] (2) adding 15 kg of butanone, guanidine nitrate is supersaturated and separated to obtain guanidine nitrate wet material;

[0035] (3) The wet guanidine nitrate is washed with isopropyl alcohol and then dried to obtain electronic grade guanidine nitrate.

[0036] Example 5:

[0037] (1) Add 10 kg of guanidine nitrate to 5 kg of ultrapure water, stir until completely dissolved, and then filter to obtain a 66.7% guanidine nitrate aqueous solution;

[0038] (2) adding 5 kg of ether, causing guanidine nitrate to be supersaturated and precipitated to obtain a wet guanidine nitrate material;

[0039] (3) The wet guanidine nitrate is washed with ether and then dried to obtain electronic grade guanidine nitrate.

[0040] Comparative Example 1:

[0041] (1) Add 10 kg of guanidine nitrate to 5 kg of ultrapure water, stir until completely dissolved, and then filter to obtain a 66.7% guanidine nitrate aqueous solution;

[0042] (2) adding 5 kg of reagent-grade ether, and guanidine nitrate is supersaturated and separated to obtain guanidine nitrate wet material;

[0043] (3) The wet guanidine nitrate is washed with reagent-grade ether and then dried to obtain purified guanidine nitrate.

[0044] Comparative Example 2:

[0045] (1) Add 5 kg of distilled water to 10 kg of guanidine nitrate, stir until completely dissolved, and then filter to obtain a 66.7% guanidine nitrate aqueous solution;

[0046] (2) adding 5 kg of reagent-grade ether, and guanidine nitrate is supersaturated and separated to obtain guanidine nitrate wet material;

[0047] (3) The wet guanidine nitrate is washed with reagent-grade ether and then dried to obtain purified guanidine nitrate.

[0048] According to the preparation methods in the above embodiments, products were obtained respectively. The metal ion content in the raw materials and products was tested by ICP-OES method, and the content of guanidine salt in the products was measured by acid-base titration test. The test results are shown in Table 1:

[0049] Table 1: Test results of Examples 1-5 and Comparative Examples 1-2

[0050]

[0051]

[0052] Examples 1-5 show that, for various guanidine salts, the preparation method of the present invention can reduce the metal ion content in the product to less than 1 ppm, while maintaining a guanidine salt content of >99.5%. This indicates that single-step recrystallization can simultaneously remove metal ion impurities and other impurities from the guanidine salt, achieving electronic grade purity.

[0053] In Comparative Example 1, ultrapure water is used to configure a guanidine salt aqueous solution, and the anti-solvent used is reagent grade ether. After the anti-solvent crystallization process, the content of sodium ions contained in the guanidine salt is reduced from 410ppm to 84ppm; in Comparative Example 2, distilled water is used to configure a guanidine salt aqueous solution, and the anti-solvent used is reagent grade ether. After the anti-solvent crystallization process, the content of sodium ions contained in the guanidine salt is reduced from 410ppm to 228ppm. The data in Comparative Example 1 and Comparative Example 2 are compared with Example 5: Example 5 uses ultrapure water to configure a guanidine salt aqueous solution, and uses pure ether as an anti-solvent. The sodium ion content in the guanidine salt after anti-solvent crystallization can be reduced from 410ppm to 0.80ppm. Analysis shows that when ordinary distilled water or reagent grade anti-solvent is used, since distilled water and reagent grade anti-solvent still contain impurities, during the recrystallization process, trace impurities will enter the guanidine salt to be purified, thereby affecting the purity of the guanidine salt, so that the purified guanidine salt still cannot reach the expected purity.

[0054] While the specific embodiments of the present invention have been described in detail above, these are merely exemplary and the present invention is not limited thereto. For those skilled in the art, any equivalent modifications and substitutions to the present invention are also within the scope of the present invention. Therefore, any equivalent changes and modifications made without departing from the spirit and scope of the present invention are intended to be encompassed within the scope of the present invention.

Claims

1. A method for preparing an electronic grade guanidine salt, characterized in that: The following steps are involved: (1) Using ultrapure water to prepare a guanidine salt aqueous solution; (2) adding an antisolvent to the guanidine salt aqueous solution to obtain a moist precipitate; (3) drying the precipitate to obtain an electronic grade guanidine salt; The mass ratio of the antisolvent to the guanidine salt aqueous solution is 0.1:1 to 10:1; Step (3) further comprises washing the wet precipitate again with an anti-solvent; The metal ion content in the anti-solvent is less than 1 ppm; The guanidine salt aqueous solution is a saturated guanidine salt aqueous solution; The preparation of the guanidine salt aqueous solution comprises filtering insoluble matter in the guanidine salt aqueous solution; The anti-solvent is methanol, ethanol, butanone, isopropanol, or ether; The guanidine salt is guanidine carbonate, guanidine phosphate, guanidine acetate, or guanidine nitrate.

Images