Method for effectively recycling 2,4-dichloro-5-fluoro acetophenone from crystallization mother liquor

A technology of fluoroacetophenone and crystallization mother liquor, applied in chemical recovery, chemical instruments and methods, separation/purification of carbonyl compounds, etc., can solve the problem of large amount of auxiliary separation reagent hydrazine hydrate, large amount of hydrochloric acid and sulfuric acid, and difficulty in recycling and other problems, to achieve the effect of low production cost, high recovery rate and simple operation

Active Publication Date: 2010-06-23
ZHEJIANG UNIV OF TECH +1
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

2,4-dichloro-5-fluoroacetophenone is prepared by using 2,4-dichlorofluorobenzene, acetyl chloride and aluminum trichloride as raw materials through the Friedel-Crafts acylation reaction. Chloro-5-fluoroacetophenone inevitably produces its isomer by-product 2,6-dichloro-3-fluoroacetophenone, and the main component of the reaction solution is 2,4-dichloro-5-fluoro Acetophenone and 2,6-dichloro-3-fluoroacetophenone, of which 2,4-dichloro-5-fluoroacetophenone content is about 80%, 2,6-dichloro-3-fluoroacetophenone The ketone content is about 20%. The melting points of 2,4-dichloro-5-fluoroacetophenone and 2,6-dichloro-3-fluoroacetophenone differ by about 10°C. Post-treatment is exactly repeated crystallization at low temperature, and

Method used

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  • Method for effectively recycling 2,4-dichloro-5-fluoro acetophenone from crystallization mother liquor

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0025] The amount ratio of the feed material is 2,4,-dichloro-5-fluoroacetophenone in the mother liquor: neopentyl glycol: the amount ratio of the acidic catalyst A is 1: 1.05: 0.1, and the acidic catalyst A is p-toluenesulfonate acid. The mass ratio of ketal:water:catalyst B is 1:2.0:0.2, and the acidic catalyst B is p-toluenesulfonic acid.

[0026] In a 250ml four-necked flask equipped with mechanical stirring, a water separator, and a reflux condenser, add 75g of 2,4-dichloro-5-fluoroacetophenone mother liquor (GC shows that its content is 40%, containing 2,4 - Dichloro-5-fluoroacetophenone 30 g), 15.8 g neopentyl glycol, 2.49 g p-toluenesulfonic acid and 75 ml toluene. Heat and stir, divide water and reflux for 2 hours, cool to room temperature, neutralize the reaction solution to neutrality with 50% sodium hydroxide solution and wash with a small amount of water to remove p-toluenesulfonic acid and excess neopentyl glycol in the system. After static separation, toluene wa...

Embodiment 2

[0030] The amount ratio of the feed material is 2,4,-dichloro-5-fluoroacetophenone in the mother liquor: neopentyl glycol: the amount ratio of the acidic catalyst A is 1: 1.05: 0.1, and the acidic catalyst A is perfluorosulfur Acid resin, organic solvent is toluene. The mass ratio of ketal:water:catalyst B is 1:5.0:0.05, and the acidic catalyst B is a perfluorosulfonic acid resin (wherein the hydrogen ion content is 0.5mmol / g, the same below).

[0031] In a 250ml four-necked flask equipped with mechanical stirring, a water separator, and a reflux condenser, add 75g of 2,4-dichloro-5-fluoroacetophenone mother liquor (containing 2,4-dichloro-5-fluorobenzene ethyl ketone 30 g), 15.8 g neopentyl glycol (12.6 g recycled neopentyl glycol + 3.2 g fresh neopentyl glycol), 29 g perfluorosulfonic acid resin and 37.5 ml toluene. Heat and stir, separate water and reflux for 1 h, cool to room temperature, and filter out perfluorosulfonic acid resin. Toluene was recovered under reduced pr...

Embodiment 3

[0035] The amount ratio of the feed material is 2,4,-dichloro-5-fluoroacetophenone in the mother liquor: neopentyl glycol: the amount ratio of the acidic catalyst A is 1: 1.2: 0.1, and the acidic catalyst A is p-toluenesulfonate acid, and the organic solvent is cyclohexane. The mass ratio of ketal:water:catalyst B is 1:2.0:0.2, and the acidic catalyst B is p-toluenesulfonic acid.

[0036] In a 250ml four-necked flask equipped with mechanical stirring, a water separator, and a reflux condenser, add 75g of 2,4-dichloro-5-fluoroacetophenone mother liquor (containing 2,4-dichloro-5-fluorobenzene ethyl ketone 30 g), 18 g neopentyl glycol (13.4 g recycled neopentyl glycol + 4.6 g fresh neopentyl glycol), 2.5 g p-toluenesulfonic acid and 113 ml cyclohexane. Heat and stir, divide water and reflux for 5 hours, cool to room temperature, neutralize the reaction solution to neutrality with 50% sodium hydroxide solution and wash with a small amount of water to remove p-toluenesulfonic aci...

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Abstract

The invention discloses a method for effectively recycling 2,4-dichloro-5-fluoro acetophenone from crystallization mother liquor, which comprises the following steps of: (a) reacting 2,4-dichloro-5-fluoro acetophenone crystallized mother liquor and neopentyl glycol as raw materials in an inert organic solution A under the action of an acidic catalyst A, then removing water continuously produced in the reaction process, and after sufficient reaction, separating and purifying to respectively obtain 2,6-dichloro-3-fluoro acetophenone and 2,4-dichloro-5-fluoro acetophenone ketal; and (b) carrying out the hydrolysis on the 2,4-dichloro-5-fluoro acetophenone ketal and water in an inert organic solution B under the action of an acidic catalyst B, and after sufficient reaction, carrying out aftertreatment to obtain the 2,4-dichloro-5-fluoro acetophenone. The invention has advanced process route, simple operation, mild reaction condition, high recycle rate of the 2,4-dichloro-5-fluoro acetophenone, environment protection and low production cost; and the neopentyl glycol of the auxiliary reagent can be recycled repeatedly, and the solidoid acidic catalyst can be recycled, thereby the invention is suitable for industrialized large-scale production.

Description

(1) Technical field [0001] The invention relates to a method for efficiently recovering 2,4-dichloro-5-fluoroacetophenone from 2,4-dichloro-5-fluoroacetophenone crystallization mother liquor. (2) Background technology [0002] 2,4-Dichloro-5-fluoroacetophenone is a key intermediate for the production of quinolones such as ciprofloxacin, enrofloxacin, and norfloxacin, with an annual market demand of more than 3,000 tons. 2,4-dichloro-5-fluoroacetophenone is prepared by using 2,4-dichlorofluorobenzene, acetyl chloride and aluminum trichloride as raw materials through the Friedel-Crafts acylation reaction. Chloro-5-fluoroacetophenone inevitably produces its isomer by-product 2,6-dichloro-3-fluoroacetophenone, and the main component of the reaction solution is 2,4-dichloro-5-fluoro Acetophenone and 2,6-dichloro-3-fluoroacetophenone, of which 2,4-dichloro-5-fluoroacetophenone content is about 80%, 2,6-dichloro-3-fluoroacetophenone The ketone content is about 20%. The melting po...

Claims

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Application Information

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IPC IPC(8): C07C49/807C07C45/85C02F9/04C02F103/36
CPCY02P20/584
Inventor 陈志卫苏为科杨郭明郑利冬黄生建姜辉王超
Owner ZHEJIANG UNIV OF TECH
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