Method for preparing electronic-grade tetramethylammonium hydroxide (TMAH)

A technology of tetramethyl ammonium hydroxide and tetramethyl ammonium bicarbonate, applied in the field of electrochemistry, can solve the problems of low product purity and current efficiency of tetramethyl ammonium hydroxide, achieve low process energy consumption, and expand the scope of application , the effect of simple process

Inactive Publication Date: 2011-10-05
ZHENGZHOU UNIV
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0005] The purpose of the present invention is to provide a method for preparing electronic-grade tetramethylammonium hydroxide, which solves the problems of low purity and current efficiency of tetramethylammonium hydroxide produced by traditional processes, and meets the needs of industrial production

Method used

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  • Method for preparing electronic-grade tetramethylammonium hydroxide (TMAH)

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Embodiment 1

[0030] In the double-membrane electrolysis device, the electrolytic cell body is made of polypropylene (PP), the cathode is made of 304 stainless steel, the anode is made of titanium-based ruthenium dioxide, the anion membrane is made of quaternized polyethersulfone anion exchange membrane, and the cation membrane is made of F4403D. Add 0.2-0.5 mol / L TMAH solution to the cathode tank, add 2.0 mol / L TMAHCO to the buffer tank 3 solution, add 0.4 mol / L Na to the anode tank 2 SO 4 solution, the electrolysis temperature is 40-60 ℃, and the electrolysis current density is 400, 500, 600, 800 and 1000 A / m 2 , to electrolyze the solution.

[0031] At the end of the electrolysis, according to the test results of the product, the current efficiency of the electrolysis process was calculated, and the results were: 80.6%, 80.9%, 83.7%, 84.9% and 80.2%, and the total metal ion content in the product was lower than 4 ppm. It can be seen that when the current density is greater than 800 A / ...

Embodiment 2

[0033] The electrolytic cell body, cathode and anode, anion and cation exchange membranes in Example 1 were used. Add 0.2-0.5 mol / L TMAH solution into the cathode tank, the electrolysis temperature is 40-60 ℃, and the electrolysis current density is 800 A / m 2 , add 0.4 mol / L Na to the anode tank 2 SO 4 solution, add 1.0, 1.5, 2.0, 2.5, 3.0 mol / L TMAHCO into the buffer tank 3 The solution is electrolyzed.

[0034] At the end of the electrolysis, according to the test results of the product, the current efficiency of the electrolysis process was calculated, and the results were: 83.6%, 86.2%, 83.9%, 82.1% and 81.5%, and the total metal ion content in the product was lower than 4 ppm. It can be seen that when TMAHCO in the buffer tank 3 When the solution concentration is greater than 1.5 mol / L, the electrolysis efficiency of the process begins to decline. Therefore, the TMAHCO in the buffer tank during electrolysis 3 The solution concentration is preferably 1.5 mol / L, and t...

Embodiment 3

[0036] The electrolytic cell body, cathode and anode, anion and cation exchange membranes in Example 1 were used. Add 0.2-0.5 mol / L TMAH solution to the cathode tank, add 0.4 mol / L NaH solution to the anode tank 2 SO 4 solution, TMAHCO in buffer tank 3 The solution concentration is 1.5 mol / L, and the electrolytic current density is 800 A / m 2 , the temperature during electrolysis is controlled at 40, 45, 50, 55, and 60 °C, and the solution is electrolyzed.

[0037] At the end of the electrolysis, according to the test results of the product, the current efficiency of the electrolysis process was calculated, and the results were: 80.1%, 87.9%, 87.3%, 84.6% and 82.5%, and the total metal ion content in the product was lower than 4 ppm. It can be seen that when the temperature of electrolysis is higher than 45 °C,

[0038] The electrolysis efficiency of the process starts to drop. Therefore, the temperature during electrolysis is preferably 45 °C, and a higher current efficienc...

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Abstract

The invention discloses a method for preparing electronic-grade tetramethylammonium hydroxide (TMAH), belonging to the field of electrochemistry. In the method, tetramethylammonium bicarbonate is used as a raw material for electrolysis, a dual-film electrolyzer is used for preparing the electronic-grade TMAH, and the whole electrolyzer implements cyclic stirring of the electrolyte in the electrolytic process in an external cycle mode. The electrolytic conditions are as follows: the cathode tank uses a 0.2-0.5 mol/L TMAH solution; the buffer tank uses a 1.0-3.0 mol/L TMAHCO3 solution; the anode tank uses a 0.2-0.6 mol/L Na2SO4 solution; the temperature for electrolysis is 40-60 DEG C; and the current density is 400-1000 A/m<2>. The invention has the advantages of simple technological process, low raw material cost, high product yield (the content of metallic ions in the product is lower than 4ppm, achieving the standard for electronic-grade TMAH), high electrolytic-current efficiency (up to 80-90%), environmental protection, no pollution and high production safety.

Description

technical field [0001] The invention relates to a method for preparing electronic-grade tetramethylammonium hydroxide, which belongs to the field of electrochemistry. Background technique [0002] Tetramethylammonium hydroxide (TMAH) is a strong base of equal strength to caustic. Because of its strong alkalinity and no residue after thermal decomposition, especially no conductive ionic substances, it is widely used in the field of electronics industry. With the continuous development of large-scale integrated circuits, the demand for high-purity electronic-grade TMAH is increasing, but the traditional method of preparing TMAH has defects such as high cost and high content of impurity ions. [0003] At present, the preparation methods of TMAH mainly include: precipitation method, ion exchange resin method, addition method, ion membrane method and ion membrane electrolysis method. The precipitation method has the disadvantages of high process cost and low product purity. Th...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C25B3/00
Inventor 任保增李涛李伟然宋怀俊雒廷亮刘振峰许小荣
Owner ZHENGZHOU UNIV
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