Method for preparing electronic grade gallic acid

Abstract

The invention discloses a method for preparing electronic grade gallic acid by using Tara powder as raw material and combining microorganism fermentation method with resin absorption. The method comprises the following steps: fermenting Tara powder with aspergillus niger to prepare raw gallic acid, decoloring the raw gallic acid in ethanol solution, filtrating to obtain filtrate, sending the filtrate through a anionic-cationic exchange resin column, performing reduced pressure evaporation to recycle ethanol until precipitating crystals, cooling, filtrating to obtain refined gallic acid and performing vacuum drying to obtain the electronic grade gallic acid. The contents of Na, Fe, K, Ca, Mg, Cu, Zn, Al and Mn ions are not more than 50ppb. The method has no pollution, high yield and low cost, the resin can be recycled and the method does not damage resin and is applicable to preparing detergent used to wash integrated circuits in electronic industry.

Description

technical field [0001] The invention relates to a method for producing electronic-grade gallic acid by using tara powder as a raw material through microbial fermentation and resin adsorption. Background technique [0002] High-purity chemicals for the electronics industry, namely MOS reagents (Moss reagents). Generally used in semiconductors, electron tubes, integrated circuit boards, etc., the highest impurity content is 0.01-10ppm, and some can be reduced to ppb levels. The dust level reaches 0-2ppb. The production of electronic-grade reagents generally uses industrial-grade products as raw materials, and the corresponding purification technology is used to remove impurities in the raw materials according to the characteristics of the raw materials. [0003] Gallic acid is also called double acid and gallic acid, its chemical name is 3,4,5-trihydroxybenzoic acid (3,4,5-trhydroxybenzoic acid), and its molecular formula is (OH 3 )C 6 h 2 COOH.H 2 O, the structural form...

AI Technical Summary

Problems solved by technology

Acid hydrolysis and alkali hydrolysis are methods of hydrolyzing gallic acid under the action of sulfuric acid or caustic soda. The basic process is divided into hydrolysis, pressure filtration, crude product crystallization, crude product centrifugation, crude product decolorization, filtration, fine crystal crystallization, fine crystal centrifugation, The finished product is obtained by vacuum drying and pulverization; sulfuric acid in the acid hydrolysis method has strong oxidizing properties, and will destroy a part of the benzene ring structure in the tannic acid during the reaction process, and the color of the crude product is very dark, and there are side reactions, and there are many impurities. It is difficult for the product processed in the subsequent process to meet the standard of electronic-grade gallic acid; the amount of caustic soda and hydrochloric acid used in the alkali hydrolysis method is very high, and the caustic soda and hydrochloric acid are neutralized to form sodium chloride, and the product contains a large amount of sodium chloride after the subsequent process. The processed products also fail to meet the standards of electronic grade gallic acid; the common disadvantages of the acid hydrolysis and alkali hydrolysis processes are: incomplete hydrolysis of tannins, low yield of gallic acid, unstable product quality, serious corrosion of equipment, production The cost is high, and more importantly, the organic wastewater pollutes the environment seriously

The microbial fermentation method uses microorganisms to ferment in an aqueous solution containing tannins, and uses glucose after hydrolysis of tannic acid as a carbon source for the growth and reproduction of microorganisms. At the same time, microorganisms are induced to produce enzymes in the solution, and tannic acid Gallic acid is produced by enzyme-catalyzed hydrolysis; the disadvantages of microbial fermentation are: long production cycle, incomplete hydrolysis, 10-20% tannin unhydrolyzed after fermentation, and product quality not up to the standard of electronic grade gallic acid

Shortcoming in this method: 1, produce a large amount of waste water in the production process (production 1 ton of electronic grade gallic acid produces 16 tons of waste water); 3. The resin is often adsorbed in the environment of 60-75 ℃, which will easily break the resin and shorten the service life of the resin; 4. Although this method can produce electronic grade gallic acid in one step, the cost is high. higher

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