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Synthesis method of 8-hydroxyquinaldine

A synthetic method and the technology of hydroxyquinaldine, which are applied in the field of synthesis of 8-hydroxyquinaldine, can solve the problems of high toxicity, limited industrial scale production, great harm to operators and production environment, and achieve low raw material cost and high process efficiency. simple effect

Inactive Publication Date: 2014-01-01
SHUANGLE CHEM PIGMENT YANGZHOU CITY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0005] The disadvantage of such methods is the use of the highly toxic crotonaldehyde
Crotonaldehyde is a state-controlled drug, which is highly toxic and has a strong lachrymatory effect, which is extremely harmful to operators and the production environment, and greatly limits industrial-scale production

Method used

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  • Synthesis method of 8-hydroxyquinaldine
  • Synthesis method of 8-hydroxyquinaldine
  • Synthesis method of 8-hydroxyquinaldine

Examples

Experimental program
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Effect test

Embodiment 1

[0030] Example 1: In a 2L glass reactor, add 109g of o-aminophenol, 30g of o-nitrophenol, 500mL of 30% hydrochloric acid and 30g of glacial acetic acid in sequence, and after fully dissolving them at 60°C, slowly add three After adding 90g of metaldehyde, keep it warm for 6 hours, pass 0.5MPa water vapor to carry out steam distillation for 3 hours, recover o-nitrophenol, cool the remaining liquid in the reaction kettle to room temperature, add 30% NaOH to neutralize to pH=6.8, Filtration, washing with hot water and drying to obtain 100 g of a yellow-brown solid crude product with a yield of 63% and a purity of 90.0% (GC detection, see Figure 5 ).

[0031] The above crude product was subjected to vacuum distillation (collecting fractions at 185-190°C / 25kPa) and recrystallization from 20% alcohol aqueous solution to obtain 65 g of white solid with a yield of 65% and a purity of 98.7% (GC detection, see Figure 6 ).

Embodiment 2

[0032] Example 2: In a 2L glass reactor, add 109g of o-aminophenol, 40g of o-nitrophenol, 500mL of 37% hydrochloric acid and 45g of glacial acetic acid in sequence. After fully dissolving them at 80°C, slowly add three Metaldehyde 105g, after adding, keep warm for 4 hours, pass 0.5MPa water vapor to carry out steam distillation for 3 hours, recover o-nitrophenol in the distillate, cool the remaining liquid in the reaction kettle to room temperature, neutralize with liquid caustic soda to pH=6 , sodium carbonate is neutralized again until no bubbles are produced, filtered, washed with hot water, and dried to obtain 109 g of brown solid crude product, with a yield of 69% and a purity of 86.0% (GC detection, see Figure 7 ).

[0033] The above crude product was subjected to vacuum distillation (185-190°C / 25kPa fraction was collected) and recrystallized from 30% alcohol aqueous solution to obtain 66.5g of white solid with a yield of 61% and a purity of 97.6% (GC detection, see F...

Embodiment 3

[0034] Example 3: In a 2L glass reactor, add 109g of o-aminophenol, 50g of o-nitrophenol, 500mL of 19% hydrochloric acid and 45g of glacial acetic acid in sequence, and after fully dissolving them at reflux temperature, slowly add three Metaldehyde 120g, after adding, keep warm for 2 hours, pass 0.5MPa water vapor to carry out steam distillation for 3 hours, recover o-nitrophenol from the distillate, cool the remaining liquid in the reaction kettle to room temperature, neutralize with ammonia water to pH=6.8, filter , washed with hot water to obtain 116g of brown solid crude product, yield 73%, purity 82.1% (GC detection, see Figure 9 ).

[0035] The above crude product was subjected to vacuum distillation (185-190°C / 25kPa fraction was collected) and recrystallized from 30% alcohol aqueous solution to obtain 71.5g of white solid with a yield of 62% and a purity of 99.7% (GC detection, see Figure 10 ).

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Abstract

The invention discloses a synthesis method of 8-hydroxyquinaldine. The synthesis method is characterized by comprising the steps of (1) fully dissolving o-aminophenol and o-nitrophenol in a mixed solution of hydrochloric acid and acetic acid at the temperature of 30-100 DEG C, slowly dropping paraldehyde at the temperature, and performing heat preservation reaction for 1-8h after the end of dropping; (2) removing unreacted o-nitrophenol by steam distillation, cooling the remaining solution to room temperature, neutralizing with an alkaline solution, and then filtering to obtain a solid crude product; (3) performing reduced pressure distillation and re-crystallization with an ethanol water solution to obtain a high-purity crystal product. According to the method disclosed by the invention, low-toxicity paraldehyde is used for replacing crotonaldehyde with severe toxicity, and the method has the advantages of simple process and low raw material cost, and is suitable for large-scale production.

Description

technical field [0001] The invention relates to a synthesis method of quinoline chemical intermediates, in particular to a synthesis method of 8-hydroxyquinaldine. Background technique [0002] 8-Hydroxyquinaldine (2-methyl-8-hydroxyquinoline) is an important fine chemical intermediate, mainly used as metal ion extractant and metal ion determination, also used in the synthesis of dyes and pigments and Preparation of pharmaceutical intermediates. [0003] At present, the process of preparing 8-hydroxyquinaldine mainly uses crotonaldehyde as the raw material, which reacts with o-aminophenol under the action of oxidizing agents (such as o-nitrophenol, iron oxide, vanadic acid and arsenic acid, etc.). The most typical is the Doebner-Miller quinoline synthesis method, which uses o-nitrophenol as an oxidant and is prepared by cyclization of crotonaldehyde and o-aminophenol in the presence of inorganic acids. [0004] [0005] A disadvantage of such methods is the use of the h...

Claims

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Application Information

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IPC IPC(8): C07D215/26
CPCC07D215/26
Inventor 陈凤太葛扣根江国强朱骥朱建军陈军
Owner SHUANGLE CHEM PIGMENT YANGZHOU CITY
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