Preparation method for tetra-alkyl ammonium hydroxide

Abstract

The invention belongs to the technical field of electrochemical synthesis and relates to a preparation method for tetra-alkyl ammonium hydroxide. A three-film four-chamber electrodialysis device is adopted, and tetra-alkyl ammonium salt serves as raw material to prepare the tetra-alkyl ammonium hydroxide. Firstly, a tetra-alkyl ammonium salt aqueous solution, pure water, anolyte and an acid solution are added to a salt chamber, a cathode chamber, an anode chamber and an acid chamber respectively, power is turned on, tetra-alkyl ammonium cations penetrate a first cation film to enter the anode chamber, anions penetrate an anion film to enter the acid chamber; the anolyte is electrolyzed to generate O2 and cations H+, and the H+ combine with the anions coming out of the salt chamber to generate anolyte after the H+ enter the acid chamber; and water molecules is electrolyzed at a negative plate to form H2 and anions OH-, and the anions OH- combine with the tetra-alkyl ammonium cations to form a tetra-alkyl ammonium hydroxide solution. The preparation method is simple in process, convenient to operate, scientific in principle, low in cost, environmentally friendly, and capable of being applied to large-scale industrial production easily.

Description

Technical field: [0001] The invention belongs to the technical field of electrochemical synthesis, and relates to a method for preparing tetraalkylammonium hydroxide, in particular to a method for preparing high-purity tetraalkylammonium hydroxide using a three-membrane four-compartment electrodialysis device. Background technique: [0002] Tetraalkylammonium hydroxide is a class of general formula R 1 R 2 R 3 R 4 Compounds of NOH, where R 1 , R 2 , R 3 , R 4 For four identical or different alkyl groups, tetraalkylammonium hydroxides, as an organic strong base, have specific uses in various industries. For example, tetramethylammonium hydroxide is the simplest tetramethylammonium hydroxide Alkyl ammonium hydroxide has a low decomposition temperature, and the decomposition products are all gaseous, without residual impurities; and tetramethyl ammonium hydroxide itself has the characteristics of strong organic base, good dissociation in water, and low content of inorgan...

AI Technical Summary

Problems solved by technology

As the tetraalkyl ammonium hydroxide used above, there are high requirements on its quality and purity. As an electronic chemical, a small amount of impurities can cause the deterioration of the semiconductor substrate; in the catalyst process using molecular sieve synthesis, tetraalkyl The impurities introduced by ammonium hydroxide will cause the deactivation of the catalyst and the reduction of the reaction efficiency; in the electrosynthesis reaction of adiponitrile, the impurity halogen ions will cause the corrosion of the electrolytic cell plate and the reduction of the current efficiency

[0003] At present, the preparation methods of tetraalkylammonium hydroxide mainly include silver oxide method, ion exchange resin method and ion membrane electrolysis method, wherein the silver oxide method uses silver oxide as raw material, the cost is higher, and the silver ion content in the final product is higher simultaneously; The ion exchange resin method obtains products with high halogen content, which cannot meet the industrial requirements; the ion membrane electrolysis method combines electrolysis and ion membrane technology, and the method is simple in process and high in product purity, and is a green synthesis process. A method for preparing tetramethylammonium hydroxide by a double-membrane method, the raw materials used are tetramethylammonium bicarbonate, anion CO 3 2－ Through the anion membrane to the anode and H + combined to form CO 2 , the process is environmentally friendly and simple, but for tetraalkylammonium salts with halogen anions, such as tetramethylammonium chloride and tetramethylammonium bromide, Cl will be precipitated at the anode 2 、Br 2 , due to the low oxidation resistance of the anionic membrane, the equipment needs to frequently replace the anionic membrane, resulting in high production costs, and the system cannot operate normally; patent CN201110446506 discloses a method for preparing tetrapropylammonium hydroxide using bipolar membrane electrodialysis , on the basis of the double-membrane method, a bipolar membrane is added, and H can be dissociated by using the bipolar membrane solution + and OH － The nature of electrodialysis achieves the purpose of electrodialysis separation. This method uses the emerging bipolar membrane instead of the plate to avoid the precipitation of simple halogens and reduce energy consumption. However, the cost of the bipolar membrane is high, the current that can pass is small, and the temperature resistance is poor. , Improper use is prone to the separation of anion and yang membranes; at the same time, due to the low ability of bipolar membranes to block the penetration of the same ions, the halogen content in the product is high, and high-purity products cannot be obtained

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