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A kind of preparation method of dye intermediate 1-naphthol-3,6-disulfonic acid (rg acid)

A dye intermediate, naphthalene disulfonic acid technology, applied in the preparation of sulfonic acid, organic chemistry and other directions, can solve the problems of many by-products, large production pollution, low yield, etc., and achieve mild reaction conditions, reduce pollution, and yield. high effect

Active Publication Date: 2017-09-15
SHENYANG RES INST OF CHEM IND
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The production cost of this method is relatively low, but it is easy to generate impurities of isomers
In addition, the preparation of 1-naphthol-3,6,8-trisulfonic acid requires the use of oleum, which has disadvantages such as inconvenient transportation, large production pollution, and harsh process conditions.
[0005] In the late 1970s, Japanese patent JP 52010226 disclosed a method for preparing aromatic phenolic compounds by high-temperature alkali fusion of aromatic sulfonic acid, in which RG acid can be prepared by this method from 1,3,6-trisulfonic acid, which is a kind of Relatively simple synthesis method, but besides certain advantages in terms of cost, this method also has many disadvantages such as many by-products, low yield, large pollution, etc. The technology is still relatively backward, and no new synthesis method has been seen since then public report

Method used

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  • A kind of preparation method of dye intermediate 1-naphthol-3,6-disulfonic acid (rg acid)
  • A kind of preparation method of dye intermediate 1-naphthol-3,6-disulfonic acid (rg acid)
  • A kind of preparation method of dye intermediate 1-naphthol-3,6-disulfonic acid (rg acid)

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0032] (1) Nitrification reaction

[0033]

[0034] Add 120 grams of 75% sulfuric acid into a 250ml four-necked bottle, and then put 34g of 2,7-naphthalene disulfonic acid with a solid content of 67.8% into the sulfuric acid, heat to 70°C to dissolve, cool down after complete dissolution, and set the temperature at 0°C Slowly add 7.5 g of concentrated nitric acid with a content of 69.3% dropwise. After the dropwise addition, add 1.38 g of phosphotungstic acid, raise the temperature to 80°C and keep it warm for 2 hours, then slowly add 20g of water dropwise to the reaction solution at 60°C to dilute the reaction solution, so that the final concentration of sulfuric acid reaches about 60%. After dilution, the mixture was cooled to room temperature and allowed to stand for one hour, then suction filtered to obtain 37.6 g of gray-green 1-nitro-3,6-naphthalene disulfonic acid filter cake with a solid content of 65.4% and a yield of 92.3%.

[0035] (2) Reduction reaction

[003...

Embodiment 2

[0042] The difference from Example 1 is that during the hydrolysis reaction, 150g of reducing solution with an amino value of 7.6% was added to a 250ml four-necked bottle and 100g of water was evaporated under reduced pressure, then 120g of 30% hydrochloric acid was quickly added to the concentrated solution, and the temperature was raised to 110 °C, keep the reaction for 10 hours. Liquid chromatographic tracking, when the normalized value of the raw material area is 0.5%, and the product area is greater than 97.2%, the reaction end point is reached. Cool down to room temperature and filter to obtain 13.4 g of gray RG acid filter cake with a content of 81.4%, a purity of 99.2%, and a yield of 95.4%.

Embodiment 3

[0044] (1) Nitrification reaction for mother liquor application

[0045]140 grams of the nitration mother liquor obtained in Example 1 were distilled to 155° C. under reduced pressure at -0.093 MPa. At this time, the concentration of sulfuric acid was about 85%, and then 34 g of 2,7-naphthalene disulfonic acid with a content of 67.8% was dropped into In sulfuric acid, after heating up and dissolving, slowly add 8.3g of concentrated nitric acid with a content of 60.8% dropwise at 20°C, then add 0.7g of phosphotungstic acid, raise the temperature to 85°C and keep it for 4 hours, then slowly drop into the reaction solution at 70°C Add dropwise 28g of water to dilute until the sulfuric acid concentration is about 60%, and filter after cooling down to stand still to obtain 35.9g of nitration filter cake with a content of 68.9% and a yield of 92.8%.

[0046] (2) Reduction reaction

[0047] Take 28.5 g of 1-nitro-3,6-naphthalene disulfonic acid obtained above with a solid content of...

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Abstract

The invention relates to the field of organic synthesis, and relates to a preparation method of a dye intermediate 1-naphthol-3,6-disulfonic acid (RG acid). According to the invention, an industrial product 2,7-naphthalene disulfonic acid is adopted as an initial material; and 1-naphthol-3,6-disulfonic acid (RG acid) with a single component and with purity reaching 98% or higher is obtained through three steps of reactions which are nitration, reduction and hydrolysis. During the preparation process provided by the invention, no waste gas and waste solid is emitted. Mother liquor produced through nitration and hydrolysis is subjected to a concentration treatment. Concentrate liquid and evaporated water can be returned to the reaction, and substantially no wastewater is discharged during the entire process. The process has the advantages of simple operation process, mild reaction conditions, and good product quality. The method provided by the invention is a novel route suitable for RG acid industrial production.

Description

technical field [0001] The invention belongs to the field of organic synthesis and relates to a preparation method of a dye intermediate 1-naphthol-3,6-disulfonic acid (RG acid). Background technique [0002] RG acid, namely 1-naphthol-3,6-disulfonic acid, also known as FC acid, is an intermediate used in the manufacture of acid dyes. The main production methods are H acid diazotization denitrification method and naphthalene sulfonation alkali fusion method. [0003] Mendeleev's Journal of the Soviet Chemical Society (1965), 10(2), 239 reported a diazotization of 1-amino-8-naphthol-3,6-disulfonic acid in the presence of copper sulfate , a method for preparing RG acid by heating under reflux in an ethanol solution; in the following twenty years, German patent DE3424477 also disclosed a method using 1-amino-8-naphthol-3,6-disulfonic acid as a starting material, heavy After nitriding, the method for preparing RG acid is treated with a reducing agent. The product yield that t...

Claims

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Application Information

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IPC IPC(8): C07C309/43C07C303/22
Inventor 刘东马瑛孟明扬高嘉新王玉灿
Owner SHENYANG RES INST OF CHEM IND
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