System and method for preparing high-purity tetrapropylammonium hydroxide through electrolysis method

A technology of tetrapropyl ammonium hydroxide and tetrapropyl ammonium bromide, applied in the field of electrochemistry, can solve the problems of poor product quality and low TPAOH current efficiency of a single-membrane electrolysis device, and achieve the effects of avoiding corrosion and improving quality

Active Publication Date: 2017-06-06
ZHEJIANG UNIV OF TECH
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  • Abstract
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Problems solved by technology

[0008] The invention provides a system for preparing high-purity tetrapropylammonium hydroxide by electrolysis, which solves the problems of low current efficiency of TPAOH prepared by the current electrolytic electrodialysis system, poor product quality of single-membrane electrolysis devices, bromine precipitation at the anode and penetration through the diaphragm. Raw materials react to produce solid products, etc.

Method used

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  • System and method for preparing high-purity tetrapropylammonium hydroxide through electrolysis method
  • System and method for preparing high-purity tetrapropylammonium hydroxide through electrolysis method
  • System and method for preparing high-purity tetrapropylammonium hydroxide through electrolysis method

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Embodiment 2-9

[0047] According to the electrolysis device of embodiment 1, RuO 2 -TiO 2 / Ti replaced by carbon steel / carbon steel, IrO 2 -Ta 2 o 5 / Ti, titanium / titanium, and different types of diaphragm materials were used to prepare 7.5% high-purity TPAOH solution by continuous electrolysis. The process parameters were the same as in Example 1, and the results are shown in Table 1.

[0048] Table 1 Experimental results of electrolytic synthesis of TPAOH solution with different electrode materials and diaphragm materials

[0049]

Embodiment 10-20

[0051] According to the electrolysis device of embodiment 1, RuO 2 -TiO 2 / Ti is a bipolar electrode, the cation exchange membrane 1 / anion exchange membrane 1 is a diaphragm material, different current densities are used, the intermediate chamber maintains different raw material concentrations, the concentration of electrolyte overflow products in the cathodic chamber, and the temperature of the electrolyte are different. Prepare 7.5% high-purity TPAOH solution under electrolysis process conditions, and the additional flow rate of raw materials and ammonia water is calculated according to the theoretical electricity. The results are shown in Table 2.

[0052] Table 2 Experimental results of electrolytic synthesis of TPAOH solution by different electrolytic processes

[0053]

Embodiment 21

[0055] According to the electrolysis device of embodiment 1, the unit electrolyzer quantity is 50, adopts 25 to connect in series, connects in two-way parallel mode. Add 5wt% ammonia water to the anolyte storage tank, add 25wt% TPABr solution to the middle tank storage tank, and add 1wt% TPAOH solution to the cathode storage tank. With the method of constant current intermittent electrolysis, the electrolysis current is 200A, the temperature is controlled from room temperature to 30°C, and the concentration of TPAOH in the electrolyte solution in the cathode area is electrolyzed to 7.5%. Control the electrolyte in the anode area to be pH<8 alkaline (if it is found to be weakly acidic, add ammonia water). After the electrolysis is finished, the TPAOH product in the cathode area is released, and the TPABr solid is added until the concentration of the solution in the middle tank is 25 wt%. The voltage of the experimental tank is 200-150V, the current efficiency is 96.23%, and th...

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Abstract

The invention provides a system and method for preparing high-purity tetrapropylammonium hydroxide through an electrolysis method. A 5wt%-25wt% tetrapropylammonium bromide solution serves as a raw material, a two-membrane three-chamber electrolyzer is adopted, tetrapropylammonium bromide in a middle chamber is dissociated to generate (CH3CH2CH2)4N+ and Br-, the cation (CH3CH2CH2)4N+ selectively penetrates a cation exchange film to form tetramethyl ammonium hydroxide together with hydroxyl in a cathode chamber; and the anion Br- selectively penetrates an anion exchange membrane to enter the cathode chamber to be oxidized to generate bromine, the bromine then reacts with ammonium hydroxide to generate ammonium bromide and nitrogen, and a 5wt%-15wt% high-purity tetrapropylammonium hydroxide solution is prepared through continuous current electrolysis according to a continuous or discontinuous method. The electrolysis process overcomes the defect that a product produced through an ion exchange method contains sodion, the beneficial effects of being low in energy consumption, high in product purity and high in current efficiency are achieved, and the bromide ion content in the product is smaller than 50 PPM.

Description

technical field [0001] The invention belongs to the technical field of electrochemistry, and in particular relates to a system and a method for preparing high-purity tetrapropylammonium hydroxide by electrolysis. Background technique [0002] Titanium silicate molecular sieve is an important new molecular sieve material in the petrochemical industry, and it is widely used in the fields of catalytic cracking and catalytic reforming in the petroleum industry. Tetrapropylammonium hydroxide (TPAOH) is an irreplaceable alkali source and templating agent for titanium silicate molecular sieves, and plays an important role in structure orientation in the synthesis process of ZSM5 molecular sieves. Tetrapropylammonium hydroxide (TPAOH), the molecular formula is C 12 h 28 NOH, like most quaternary ammonium bases, is easy to absorb moisture and dissolve in water. When exposed to the air, it can absorb carbon dioxide in the air, and it is easy to decompose when heated. [0003] At pr...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C25B3/00C25B9/18
CPCC25B3/00C25B9/70
Inventor 甘永平张文魁黄辉夏阳梁初张俊
Owner ZHEJIANG UNIV OF TECH
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