Method for preparing 2, 5-diphenyl amino acid DATA

Abstract

The invention relates to a method for preparing 2, 5-diphenyl amino acid DATA, which adopts DMSS and aniline as raw materials, and comprises the following steps: (1) mixing of ingredients; (2) heating and dissolution; (3) condensation reaction; (4) oxydrolysis; (5) separation of solid and liquid; (6) adsorption and decontamination; (7) separation of solid and liquid; (8) neutralization and acidification; (9) separation of solid and liquid; (10) washing and dehydration; (11) drying; (12) crushing and package; and the product 2, 5-diphenyl amino acid DATA is obtained through the above steps. The method has the advantages of reasonable process, high product purity, stable quality, high yield and safe and reliable reaction process.

Description

technical field [0001] The invention relates to a compound for preparing organic pigments, which is an important intermediate for the manufacture of quinacridone series organic pigments. The method for preparing 2,5-diphenylamino-terephthalylene DATA through condensation reaction, hydrolysis oxidation reaction and neutralization acidification reaction as raw materials, dimethyl ester DMSS and aniline AN, belongs to the technical field of fine chemical industry. Background technique [0002] Quinacridone pigments are a very important class of high-grade organic pigments, with excellent light fastness, heat fastness, and non-migration in various plastics, so they are widely used in high-grade coatings, engineering plastics, It is also used in the coloring of resin, pigment printing, ink and rubber, and also in the coloring of synthetic fibers, and has broad application prospects. [0003] 2,5-di-anilino-3,6-dihydro-terephthalic acid dimethyl ester, (2,5-di-anilino-3,6-dihydro...

AI Technical Summary

Problems solved by technology

[0013] (1) In the condensation reaction process, DMSS and aniline AN are carried out condensation reaction in organic solvents such as methanol, ethanol, because the solubility of DMSS in the solution of methanol, ethanol etc. is limited, and the boiling point of methanol, ethanol is low, in carrying out In the condensation reaction process, it is difficult to completely dissolve DMSS, and the product generated is also a solid product. Therefore, the condensation reaction process efficiency of dimethyl succinyl succinate and aniline is low, the reaction is difficult to carry out thoroughly, and the solid product produced by the condensation reaction easily entrained reactants

Furthermore, water H is produced as a by-product during the condensation reaction. 2 O, resulting in difficulties in the recovery of organic solvents, low selectivity and conversion of products, usually in order to increase the operating temperature of the reaction system, usually need to adopt pressure operation, there are potential safety hazards in the operation process;

[0014] (2) in DMSS and AN through the hydrolysis of condensation reaction product, oxidation reaction process, because the solubility of 2,5-dianilino dimethyl terephthalate salt in water or methanol, ethanol aqueous solution is little, cause The hydrolysis and oxidation reaction proceeds slowly, and it is difficult to carry out the hydrolysis and oxidation reactions thoroughly. In order to obtain the 2,5-dianiline dimethyl terephthalate salt solution, it is necessary to add a large amount of water or alcohol aqueous solution, resulting in low efficiency in the process and the amount of waste water large, difficult to handle;

[0015] (3) In the process of preparing 2,5-diaminoterephthalic acid in the neutralization acidification reaction of the purified 2,5-dianilino terephthalic acid dimethyl salt solution after hydrolysis and oxidation, because after hydrolysis and oxidation The solution concentration of the generated 2,5-dianilino dimethyl terephthalate salt is low, resulting in the addition of acid to the refined mother liquor obtained after neutralization and acidification to obtain 2,5-diaminoterephthalic acid The solid crystal is small, the production efficiency is small, and the product purity is low;

[0016] (4) In all chemical reaction processes, the reaction rate of the general liquid-liquid system is greater than the reaction rate of the liquid-solid system. Therefore, it is generally necessary to avoid the solid-solid reaction system, so that liquid-liquid → produces liquid-solid, Therefore, solid-liquid produces liquid-liquid reaction system. For the system of solid crystalline materials, in principle, the upper limit of the operating temperature is the boiling point of the lowest solvent, and the lowest operating temperature is the melting point of the highest substance, unless it is necessary to dissolve the crystalline product in the solvent. Because in the current preparation process, methanol and ethanol aqueous solution are mainly used as solvents, so the reaction is difficult to carry out thoroughly, or in order to obtain the same system of solution phase materials, a large amount of solvents need to be used, which makes the recovery and treatment of solvents difficult, and there are flammable and flammable danger of explosion;

[0018] (6) The amount of waste water produced in the traditional production process is large, difficult to deal with, and serious environmental pollution

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