Method for preparing and concentrating tetraethylammonium hydroxide with membrane integration technique

Abstract

The invention provides a method for preparing and concentrating tetraethylammonium hydroxide with a membrane integration technique. The method comprises steps as follows: an aqueous tetraethylammoniumsalt solution is introduced into a feed liquid chamber of a bipolar-membrane electrodialysis device, pure water is introduced into an acid liquor chamber and an alkali liquor chamber respectively, and a sulfuric acid solution is introduced into electrode liquor chambers and a buffer solution chamber respectively; a direct-current electric field is applied to an anode plate and a cathode plate, cations (CH3CH2)4N<+> in the feed liquid chamber enter the alkali liquor chamber through a cation exchange membrane, and anions X<-> in the feed liquid chamber enter the buffer solution chamber throughan anion exchange membrane; the cations (CH3CH2)4N<+> and hydroxyl ions produced by bipolar-membrane hydrolytic dissociation are bound to generate tetraethylammonium hydroxide in the alkali liquor chamber, the tetraethylammonium hydroxide is collected and subjected to membrane distillation, and an aqueous tetraethylammonium hydroxide solution with mass concentration being 15%-20% is obtained. According to the method, bipolar-membrane electrodialysis and membrane distillation technologies are integrated, and the prepared aqueous tetraethylammonium hydroxide solution is high in concentration, low in impurity content and low in production cost.

Description

technical field [0001] The invention belongs to the technical field of compound preparation, and in particular relates to a method for preparing and concentrating tetraethylammonium hydroxide by utilizing membrane integration technology. Background technique [0002] Tetraethylammonium hydroxide is an organic base, a catalyst in the synthesis of silicone products such as silicone rubber, silicone resin, and silicone oil; it is widely used in the electronics industry as a cleaning, etching, and polishing reagent for integrated circuit boards. Anisotropic etching of Si-SiO2 interface used in semiconductor micromachining technology. In addition, it can also be used as a phase transfer catalyst, template agent for molecular sieve synthesis, cleaning agent, and impurity removal agent in the petroleum industry. Its traditional production methods include electrolysis, ion exchange resin method, silver oxide method, membrane electrolysis method, etc., but these methods have insurmo...

AI Technical Summary

Problems solved by technology

Its traditional production methods include electrolysis, ion exchange resin method, silver oxide method, membrane electrolysis method, etc., but these methods have insurmountable defects: electrolysis method has high energy consumption, and the process has by-product Cl2; ion exchange The conversion rate of the resin method is not high, accompanied by a large amount of waste liquid discharge, which is easy to cause harm to the environment; the production cost of the silver oxide method is relatively expensive, and large-scale industrial production cannot be carried out; the membrane electrolysis method can prepare high-purity quaternary ammonium alkali, but The production process consumes a lot of energy, making it difficult to save energy and reduce consumption

However, due to the influence of the performance of anion and cation exchange membranes, bipolar membrane electrodialysis still has problems such as membrane fouling and ion leakage in the production of high-concentration acids and bases.

The concentration of tetraethylammonium hydroxide prepared at the same time is not high, and contains impurity ions, it is difficult to meet the high quality requirements of tetraethylammonium hydroxide

Images