Preparation process of 2-methyl-3-hydroxyquinoline-4-carboxylic acid

A hydroxyquinoline and preparation technology, applied in the direction of organic chemistry, can solve the problems of cumbersome operation and waste of energy, and achieve the effect of reducing energy cost, simplifying operation and equipment

Inactive Publication Date: 2018-12-07
JIANGSU HUAER CHEM
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Complicated operatio

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0010] In a 2000ml four-necked flask, add 1000ml of water at 35°C, add 39g of lime (reduced to pure), 7.48g of sodium hydroxide (reduced to pure), 50g of isatin under stirring, stir at room temperature for 30 minutes, and start to add 32.4g (Purity conversion) 1 monochloroacetone, dropwise added in 1.5 hours, due to the exothermic reaction, the temperature rose to 62°C after the dropwise addition, continued to stir for 2 hours, adjusted the pH value to 1.0 with hydrochloric acid, suction filtered, drained as much as possible, and kept at room temperature Wash with water until neutral, drain, discharge, dry, and test the content. Obtain product 68 grams, content 98.5%.

Embodiment 2

[0012] In a 2000ml four-neck flask, add 1200ml of water at 20°C, add 38g of lime (reduced to pure), 7.2g of sodium hydroxide (reduced to pure), 50g of isatin under stirring, stir at room temperature for 30 minutes, and start to drop 32.1 Gram (pure) 1 monochloroacetone, the dropwise addition is completed in 1.7 hours, the temperature rises to 45°C after the dropwise addition, continue to stir for 2 hours, adjust the pH value to 0.98 with hydrochloric acid, filter with suction, drain as much as possible, wash with water at room temperature until neutral , drained, discharged, dried, and tested for content. Obtain product 67.8 grams, content 98.3%.

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PUM

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Abstract

The invention discloses a preparation process of 2-methyl-3-hydroxyquinoline-4-carboxylic acid, belonging to the field of organic synthesis. The process comprises the steps of adding water, calcium hydroxide, sodium hydroxide and isatin into a container, stirring for over half an hour, dropwise adding chloroacetone after 1-2 hours, stirring for over 2 hours after the dropwise adding, directly adjusting the pH to 1.0+/-0.2 with hydrochloric acid, filtering, and washing, so as to obtain the product. The preparation process has the beneficial effects that the heating and cooling processes are omitted in the whole process, the operation and the equipment are simplified, the energy cost is lowered, the optimal molar proportion of calcium hydroxide to sodium hydroxide is controlled at 3 to 1;onone hand, the reaction fluidity is facilitated, and on the other hand, the quality stability of the product is improved.

Description

technical field [0001] The invention relates to an improved preparation process of 2-methyl-3-hydroxyquinoline-4-carboxylic acid, which belongs to the technical field of organic synthesis. Background technique [0002] 2-Methyl-3-hydroxyquinoline-4-carboxylic acid is an important dye intermediate, which can be used for dye dispersing No. 54 yellow, dispersing No. 64 yellow and as an intermediate of some medicines. The market demand is large and the prospect is broad. The synthesis process of 2-methyl-3-hydroxyquinoline-4-carboxylic acid is to add quantitative calcium hydroxide and isatin in water, stir and dissolve, then add quantitative chloroacetone dropwise under low temperature conditions, and heat up to a certain temperature after the dropwise addition. temperature, keep warm and then lower the temperature, then add hydrochloric acid dropwise, adjust the pH value to strong acidity, precipitate the product 2-methyl-3-hydroxyquinoline-4-carboxylic acid, filter and wash to...

Claims

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Application Information

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IPC IPC(8): C07D215/50
CPCC07D215/50
Inventor 詹国青
Owner JIANGSU HUAER CHEM
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