High-yield and low-cost method for refining and purifying long-carbon-chain dicarboxylic acid

Abstract

The invention relates to a high-yield and low-cost method for refining and purifying long-carbon-chain dicarboxylic acid. The method comprises the following steps: (1) the raw material crude long-chain dicarboxylic acid for refining and purifying does not need to be dried; (2) decolorizing and filtering are carried out to obtain a decolorizing agent filter cake, and the decolorizing agent filter cake is washed with a solvent acetic acid; (3) before the solvent is recovered from the recrystallization mother liquor, watering-out crystallization is carried out first, and then, the long-carbon-chain dicarboxylic acid product dissolved in the crystallization mother liquor is extracted again; and (4) the solvent in the filtered mother liquor after watering-out crystallization is recovered by adopting an azeotropic distillation method, and sec-butyl acetate is selected as an entrainer. The refined and purified long-carbon-chain dicarboxylic acid reaches the following technical indexes: the single acid is greater than or equal to 99.30 wt%, the total acid is greater than or equal to 99.80 wt%, the ash content is less than or equal to 15ppm, the iron content is less than or equal to 1ppm interms of Fe2O3, the total nitrogen content is less than or equal to 15ppm in terms of N element, and the water content is less than or equal to 0.2 wt%. The refining and purifying yield of the long-carbon-chain dicarboxylic acid is greater than or equal to 96.00%.

Description

technical field [0001] The invention is a method for refining and purifying long carbon chain dicarboxylic acids with high yield and low cost. It belongs to the purification treatment of acyclic dicarboxylic acids with more than 10 carbon atoms. Background technique [0002] Long-chain dicarboxylic acid (along-chain dicarboxylic acid)—a straight-chain dicarboxylic acid with more than 10 carbon atoms in the carbon chain, is an important class of fine chemical products. Main raw materials for synthesizing polyamide resins, polyester resins, hot melt adhesives, spices, weather-resistant plasticizers, lubricating oil additives, coatings, liquid crystals, etc. [0003] The main industrial applications include artificial synthesis of muscone; coil adhesives used for a long time at 100°C; hot-melt adhesives for clothing setting; not only can manufacture high-temperature resistant lubricants, but also can manufacture effective at -45°C low temperature Lubricating lubricant; high-p...

AI Technical Summary

Problems solved by technology

However, because the moisture carried by the crude raw material reduces the solubility of the long carbon chain dicarboxylic acid refined and purified in the acetic acid solvent, part of the long carbon chain dicarboxylic acid crystallization enters the filter cake with the activated carbon, causing the loss of the dicarboxylic acid, thereby Reduced dibasic carboxylic acid refining purification yield

[0014] 2. After the crystallization mother liquor is recovered from the solvent, the obtained heavy components are repeatedly recovered and used as refined and purified raw materials, resulting in the accumulation of other mixed dibasic acids and other impurities produced during the fermentation process, which affects the quality of long-chain dicarboxylic acid products

In addition to reducing the recovery yield of by-products, it will also increase the difficulty of the subsequent decolorization and purification process, and even adversely affect the quality of by-products

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