Mixed long-carbon-chain dicarboxylic acid and preparation method thereof

Abstract

The invention relates to a mixed long-carbon-chain dicarboxylic acid and a preparation method thereof, wherein a heavy component material obtained after a solvent acetic acid is recovered from a recrystallization filtering mother liquor generated in a dodecanedioic acid recrystallization refining process is used as a raw material to prepare the mixed long-carbon-chain dicarboxylic acid. The methodcomprises the following steps: adding deionized water into the heavy component material raw material, heating while stirring, carrying out standing layering, and removing the lower-layer short carbonchain mixed acid impurities in a molten state; carrying out cooling crystallizing on the upper-layer extracting solution, and filtering to obtain a crude product; recrystallizing, refining and purifying the obtained crude product to obtain the mixed long-carbon-chain dicarboxylic acid, wherein the product quality reaches the following technical indexes that the total acid (based on a dodecanedioic acid main product) is greater than or equal to 99.00 wt%, and the platinum-cobalt color is less than 10. The invention provides a mixed long-carbon-chain dicarboxylic acid product being high in purity and good in color and luster and capable of being used as a synthesis raw material for synthesizing industrial products such as a dibasic acid salt surfactant, an alkylol amine salt anti-rust and anti-wear agent, artificially synthesized musk and the like, and a preparation method thereof.

Description

Technical field [0001] The invention is a mixed long-carbon chain dicarboxylic acid and a preparation method thereof. It belongs to the purification treatment of acyclic dicarboxylic acids with more than 10 carbon atoms. Background technique [0002] Dodecanedioic Acid is also known as lauric acid. It is an industrial product that has been developed earlier and has a larger output among long carbon chain dicarboxylic acids. Mainly used to synthesize polymer materials, spices, medicines, etc. Among them, it is one of the most important uses as a polycondensation monomer and diamine to synthesize long carbon chain nylon (also known as polyamide resin) engineering plastics. [0003] Nylon is a type of polymer compound containing amide group (-NHCO-) ​​on the molecular backbone. Because nylon contains a large number of amide groups in its molecular structure, and the macromolecular ends are amino or carboxyl groups, it is a kind of crystalline polymer with strong polarity, hydrogen...

AI Technical Summary

Problems solved by technology

It is difficult to meet the technical requirements of users

[0020] 2. During the fermentation process, the accompanying short carbon chain mixed dicarboxylic acids below carbon 9 have not been removed in the preparation method of the prior art, and are the main impurities in the mixed long carbon chain dicarboxylic acid products

The existence of this part of impurity makes it difficult to use the mixed long carbon chain dicarboxylic acid product of the prior art as a synthetic raw material

[0021] 3. The method of natural drying wastes solvent resources, occupies valuable land, pollutes the atmosphere and water environment, etc.

With the existing technology, about 0.4 tons of long-carbon chain mixed dibasic acids can be produced per ton of rectified heavy components, that is, for every 1 ton of long-carbon chain mixed dibasic acids produced, an average of 0.875 tons of acetic acid gas escapes into the air, resulting in The waste of acetic acid solvent causes air pollution again

0.375 tons of acetic acid entered the sewage treatment system, which undoubtedly increased the sewage treatment load

[0023] 4. The method of natural drying, neutralization into salt and dissolution, twice decolorization and sulfuric acid acidification and crystallization, the process is cumbersome

Product color is difficult to meet user requirements

[0024] The mixed long carbon chain dibasic acid obtained in the prior art has a total acid content of ≤85% based on the refined dodecyl dicarboxylic acid main product, a total nitrogen content of ≥160ppm, an ash content of ≥200ppm, and a platinum-cobalt chroma greater than 85

[0025] 5. Since the solvent has a decisive influence on the decolorization effect of activated carbon, the decolorization effect of activated carbon on aqueous solution is much smaller than that on organic solution

Therefore, in the above-mentioned decolorization process, although two decolorizations have been adopted, it is still difficult to solve the problem of the deep chroma of the rectification heavy component. The platinum-cobalt chroma of the mixed long carbon chain dicarboxylic acid obtained by this method is generally more than 85

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