Purification method of long-carbon-chain dicarboxylic acid

Abstract

The invention relates to a purification method of long-carbon-chain dicarboxylic acid, belonging to purification treatment of cycle-free dicarboxylic acid with more than 10 carbon atoms. The invention is characterized in that recrystallizing purification is performed by using a long-carbon-chain dibasic acid crude product produced by a microbial fermentation process as an initial raw material and methanol as a solvent. The method comprises the following steps: (1) dissolving and decolorizing: a. feeding at room temperature, b. dissolving by preheating, c. decolorizing by adsorption, and d. four-stage filtering; (2) gradient cooling and crystallization; (3) eluting and centrifugal filtration; and (4) vacuum drying. The technical indexes of the purified long-carbon-chain dicarboxylic acid are as follows: the single acid content is at least 90.20%, the total acid content is 99.60 wt%, the ash content is at most 30 ppm, the iron content on the basis of Fe2O3 is at most 2 ppm, the total nitrogen on the basis of N is at most 30 ppm, the moisture content is at most 0.4 wt%, and no ester content is detected. The purification yield of C11-C14 is greater than or equal to 98.4%. The long-carbon-chain dicarboxylic acid is suitable to be used as a polycondensation monomer to perform polycondensation reaction with diamine to synthesize the long-carbon-chain nylon, and is also suitable to be used as a raw material of synthetic perfume and drugs. The purification method of long-carbon-chain dicarboxylic acid has the advantages of favorable product color, high product purity, high refinement yield and lower cost.

Description

technical field [0001] The invention is a method for purifying long carbon chain dicarboxylic acids. 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] Use long-chain dicarboxylic acids as raw materials to develop plasticizers with excellent performance used in the production of PVC (polyvinyl chloride), such as long-chain dibasic acid dibutanol ester, dihexyl alcohol ester, dioctyl alcohol ester, etc. . Replace existing phthalic acid and aliphatic dibasic acid esters; develop long-chain dibasic acid d...

AI Technical Summary

Problems solved by technology

When polyamide is used as a raw material to produce polyamide products, short chains will be polymerized, and it is difficult to produce high-molecular polymers with high polymerization degree and regular molecular weight, which will affect the mechanical properties of the product.

And glacial acetic acid is extremely corrosive when the temperature exceeds 60°C. Even if expensive titanium equipment is used, the equipment cannot be completely prevented from being corroded.

[0014] 2. Most of the solvents used in the ethanol refining process are edible alcohol. The price of edible alcohol is high. The current market price is 7000-9000 yuan / ton, which greatly increases the production cost

At present, the ethanol refining process has gradually matured, basically solving the problem of esterification side reactions in the refining process, but because the esterification reaction activity of methanol is much greater than that of ethanol, the problem of side reactions is always the bottleneck of the methanol refining process

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