Preparation method of 1,4-naphthalic acid

A technology of naphthalene dicarboxylic acid and naphthoic acid, which is applied in the field of 1, and can solve problems such as difficulty in obtaining 1-methyl-4-naphthoic acid

Pending Publication Date: 2021-05-11
HUBEI HONGXIN CHEM CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Its disadvantage is also that the starting material 1-methyl-4-naphthoic acid is difficult to obtain

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0024] In a 2000mL four-neck flask, add 500mL of dry ethylene chloride, then add 160g of aluminum chloride and 94g of acetyl chloride successively, and stir the mixture at 30-35°C until a transparent solution is formed. At this point, 207 g of 1-bromonaphthalene previously dissolved in 250 mL of vinyl chloride was added, the temperature was raised to 90° C., and the mixture was stirred for 30 minutes. The reaction mixture was cooled to room temperature, and the resulting precipitated aluminum chloride / 4-bromo-1-acetylnaphthalene complex was filtered under negative pressure and washed several times with a small amount of vinyl chloride. The obtained complex was added to 2000mL 2M hydrochloric acid, heated to 100°C for decomposition, and at the same time, vinyl chloride was distilled off. After cooling to room temperature, stirring at the same time resulted in precipitation, and 4-bromo-1-acetylnaphthalene crystals were obtained. Filter with suction, wash the residual acid with...

Embodiment 2

[0029] The preparation of 4-bromo-1-naphthoic acid is carried out according to the method of embodiment 1.

[0030] 125.6g of 4-bromo-1-naphthoic acid and 51g of cuprous cyanide were added to 330mL of anhydrous quinoline. The mixture was then heated to 235-240°C under reflux and reacted for 4 hours to form a homogeneous dark solution. The reaction solution was cooled to 120°C, and then 750mL of 15% sodium hydroxide solution was added to produce a yellow-brown suspension, which was then heated to reflux. The concentrate uses a liquid separation device to discard the aqueous quinoline with a large specific gravity. After the 4-cyanonaphthoic acid / copper bromide complex is completely hydrolyzed or quinoline is completely removed (about 6 hours), the reaction mixture is cooled to 80°C ,, adjust the pH value of the mixture to 7.0-7.5 with about 230mL concentrated hydrochloric acid, filter out the copper oxide precipitate, continue to adjust the pH value of the filtrate with 90mL c...

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Abstract

The invention relates to a preparation method of 1,4-naphthalic acid, which is characterized by comprising the steps of performing Friedel-Crafts reaction on 1-naphthalene bromide serving as an initial raw material and acetyl chloride to generate 4-bromo-1-acetyl naphthalene; then carrying out oxidation by using pypocholoride to obtain 4-bromo-1-naphthoic acid; reacting 4-bromine-1-naphthoic acid with cuprous cyanide in a polar aprotic solvent in the presence of potassium iodide and copper sulfate in catalytic doses to generate a 4-cyano naphthoic acid copper salt complex; and carrying out alkaline hydrolysis on the 4-cyano naphthoic acid copper salt complex to obtain the 1,4-naphthalic acid. According to the preparation method of the naphthalene-1,4-dicarboxylic acid, the raw materials are easy to obtain, and the product does not contain color impurities, is high in purity and good in quality, and can be directly used as an intermediate of a dye, an ultraviolet light absorber, a scintillator and an optical whitening agent for further synthesis.

Description

technical field [0001] The invention belongs to the field of fine chemicals, and in particular relates to a preparation method of 1,4-naphthalene dicarboxylic acid. Background technique [0002] 1,4-Naphthalenedicarboxylic acid (1,4-NDCA, 1,4-naphthalenedicarboxylic acid) is an intermediate in the synthesis of fluorescent whitening agent KCB, so it is called KCB acid; it is also an important component in the synthesis of other dyes, pigments, resins, and drugs Intermediate; It can also be used as a mixed material additive in the field of clothing materials, high-strength container materials and other materials. [0003] At present, the synthesis process of 1,4-naphthalene dicarboxylic acid mainly contains the following methods: [0004] Using 1,4-dimethylnaphthalene as the starting material, there are three methods: one is the three-step synthesis method of 1,4-dimethylnaphthalene (bromination, cyano substitution, hydrolysis) (US4375556A, US4376214A, CA1072109A) , the meth...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C51/08C07C63/38C07C253/14C07C255/57C07C51/295C07C61/40C07C45/46C07C49/813
CPCC07C51/08C07C253/14C07C51/295C07C45/46C07C49/813C07C61/40C07C255/57C07C63/38
Inventor 杨玉忠
Owner HUBEI HONGXIN CHEM CO LTD
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