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Preparation method of p-chloropropiophenone

A technology of chloropropiophenone and p-chlorobenzoic acid, which is applied in the field of pharmaceutical intermediates, can solve problems such as high product cost, unsatisfactory results, and complicated operation process, and achieve low cost, moderate reaction time, and high product purity. Effect

Inactive Publication Date: 2010-08-18
NANTONG UNIVERSITY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Because meta-position and ortho-position substituents with very close boiling points are generated simultaneously during the chlorination reaction, separation and purification are difficult, and the separation requires a solvent method. The operation process is complicated and seriously pollutes the environment
Other relevant synthetic methods of p-chloropropiophenone, its results are not ideal enough
Also because of the specificity of the product in the synthesis method and some difficulties in the process, the product yield is extremely low, resulting in high product costs

Method used

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  • Preparation method of p-chloropropiophenone

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0018] In a four-necked reaction flask equipped with an electric stirrer, a reflux condenser, and a thermometer, add 15.65 g of p-chlorobenzoic acid, 51.8 g of propionic acid, and 2.5 g of catalyst in sequence. After adding the materials, start stirring and control the condensation reaction temperature to 140°C. For about 12 hours, carry out the condensation reaction by stirring for 12 hours, distill off excess propionic acid, and continue to rise in temperature until carbon dioxide gas begins to escape at 280°C, and carry out decarboxylation reaction at a temperature of 280°C-285°C, while using 95% ethanol solution Absorb the escaped carbon dioxide gas and distilled liquid, stop the reaction when there is no liquid distilled out in the four-port reactor after decarboxylation reaction for 2 hours, then cool and crystallize to obtain p-chloropropiophenone product, the yield of p-chloropropiophenone It reaches 86.45%, and the melting point is 34-37°C.

Embodiment 2

[0020] In a four-necked reaction flask equipped with an electric stirrer, a reflux condenser, and a thermometer, add 15.65 g of p-chlorobenzoic acid, 51.8 g of propionic acid, and 3.5 g of catalyst in sequence. After adding the materials, start stirring and control the condensation reaction temperature to 140°C. For about 12 hours, carry out the condensation reaction by stirring for 12 hours, distill off excess propionic acid, and continue to rise in temperature until carbon dioxide gas begins to escape at 280°C, and carry out decarboxylation reaction at a temperature of 280°C-285°C, while using 95% ethanol solution Absorb the escaped carbon dioxide gas and the distilled liquid, stop the reaction after 2 hours when there is no liquid distilled out in the four-port reactor, then cool and crystallize to obtain the p-chloropropiophenone product, and the yield of p-chloropropiophenone reaches 87.71 %, the melting point is 34-37°C.

Embodiment 3

[0022] In a four-necked reaction flask equipped with an electric stirrer, a reflux condenser, and a thermometer, add 15.65 g of p-chlorobenzoic acid, 59.2 g of propionic acid, and 2.5 g of catalyst in sequence. After adding the materials, start stirring and control the condensation reaction temperature to 140°C. For about 12 hours, carry out the condensation reaction by stirring for 12 hours, distill off excess propionic acid, and continue to rise in temperature until carbon dioxide gas begins to escape at 280°C, and carry out decarboxylation reaction at a temperature of 280°C-285°C, while using 95% ethanol solution Absorb the escaped carbon dioxide gas and the distilled liquid, stop the reaction after 2 hours when there is no liquid distilled out in the four-port reactor, then cool and crystallize to obtain the p-chloropropiophenone product, and the yield of p-chloropropiophenone reaches 86.81% %, the melting point is 34-37°C.

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Abstract

The invention discloses a preparation method of p-chloropropiophenone. Parafluorobenzoic acid and propionic acid serve as raw materials; in the presence of catalyst, the raw materials react to prepare the p-chloropropiophenone, and the catalyst is reduced iron powder. The invention adopts the novel catalyst to synthetize the p-chloropropiophenone, thereby simplifying the separation and purification processes. The invention has short reaction time and high product yield, the yield of the product can reach above 86%, and the invention has higher purity in the obtained product, low energy consumption, less environment pollution and low cost. The invention is a more ideal process for realizing industrialized production.

Description

Technical field: [0001] The invention relates to a preparation method for preparing p-chloropropiophenone, belonging to pharmaceutical intermediates. Background technique: [0002] 4-Chloropropiophenone is an aromatic asymmetric ketone compound, white crystalline solid with a melting point of 34-37°C. 4-Chloropropiophenone is an important structural intermediate. It is mainly used as a pharmaceutical intermediate for the synthesis of new weight loss drug rimonabant (N-(piperidine)-5-(4-chlorophenyl)-1-(2,4-dichlorophenyl)-4- Methyl-IH-pyrazole-3 carboxamide) key intermediates α-bromo-p-chloropropiophenone and 4-(4-chlorophenyl)-3-methyl-2,4-dioxobutanoic acid ethyl Esters; can also be used as fine chemical raw materials for the synthesis of fine chemical products containing p-chlorobenzene ring structure in the molecule, and can also be used as intermediates for other medicines and pesticides. [0003] Its chemical name is: p-chloropropiophenone or 4-chloropropiophenone ...

Claims

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Application Information

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IPC IPC(8): C07C49/807C07C45/65
Inventor 王树清汤艳峰高崇石玉军景晓辉丁欣宇
Owner NANTONG UNIVERSITY
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