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A kind of method of synthesizing p-bromopropiophenone

A technology for bromopropiophenone and p-bromobenzoic acid, which is applied in the direction of condensation preparation of carbonyl compounds, organic chemistry, etc., can solve problems such as difficult product purity control, difficult product separation, low product yield, etc., and achieves low cost, separation and purification process. Simple, high product yield effect

Inactive Publication Date: 2011-11-30
NANTONG UNIVERSITY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] Though p-bromopropiophenone has been used earlier, there is no report about the synthetic domestic literature of p-bromopropiophenone. According to the structure of p-bromopropiophenone and existing synthetic work experience, the synthetic process route of p-bromopropiophenone is based on other methods. The synthetic method of aromatic ketone, namely, in the presence of anhydrous aluminum trichloride catalyst, with bromobenzene and propionyl chloride as raw materials, directly carry out acid chloride reaction to synthesize p-bromopropiophenone, but there are o-bromopropiophenone and a small amount of There are two isomers of m-bromopropiophenone, the product separation is difficult, and the product purity is not easy to control
The method has the disadvantages of complex process, low product yield and high production cost.

Method used

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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, 20.1 g of p-bromobenzoic acid, 44.4 g of propionic acid, and 6 g of a composite catalyst were added successively. After the addition, the stirring was started and the condensation reaction temperature was controlled to be 130- At about 140°C, carry out the condensation reaction by stirring for 6-10h, distill off the excess propionic acid, and continue to rise the temperature until 220°C, when gas begins to escape, carry out the decarboxylation reaction at 220°C-230°C, and use 95 % ethanol solution to absorb the escaped gas and distilled liquid, after decarboxylation reaction for 0.5-1.0h, stop the reaction if there is no liquid distilled out in the four-port reactor, then cool and crystallize to obtain p-bromopropiophenone products, p-bromobenzene The yield of acetone reaches 77.67%, and the melting point is 45-47°C.

Embodiment 2

[0020] In a four-necked reaction flask equipped with an electric stirrer, a reflux condenser and a thermometer, 20.1 g of p-bromobenzoic acid, 51.8 g of propionic acid, and 6 g of composite catalyst were added successively. At about 140°C, carry out the condensation reaction by stirring for 6-10h, distill off excess propionic acid, and continue to rise in temperature until 220°C when gas begins to escape, and carry out decarboxylation reaction at 220-230°C, while using 95% The ethanol solution absorbs the escaped gas and distilled liquid. After 0.5-1.0h, there is no liquid distilled out in the four-port reactor, then the reaction is stopped, and then cooled and crystallized to obtain the p-bromopropiophenone product. The yield reaches 77.92%, and the melting point is 45-47°C.

Embodiment 3

[0022] In a four-necked reaction flask equipped with an electric stirrer, a reflux condenser, and a thermometer, 20.1 g of p-bromobenzoic acid, 59.2 g of propionic acid, and 6 g of composite catalyst were added successively. At about 140°C, carry out the condensation reaction by stirring for 6-10h, distill off excess propionic acid, and continue to rise in temperature until 220°C when gas begins to escape, and carry out decarboxylation reaction at 220-230°C, while using 95% The ethanol solution absorbs the escaped gas and distilled liquid. After 0.5-1.0h, there is no liquid distilled out in the four-port reactor, then the reaction is stopped, and then cooled and crystallized to obtain the p-bromopropiophenone product. The yield reaches 77.26%, and the melting point is 45-47°C.

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Abstract

The invention discloses a method for synthesizing p-bromopropiophenone, which uses p-bromobenzoic acid and propionic acid as raw materials to prepare p-bromopropiophenone through reaction in the presence of a composite catalyst. The invention adopts a novel composite catalyst to synthesize p-bromopropiophenone, the separation and purification process is simple, the reaction time is short, the yield of the product reaches more than 77%, the obtained product has high purity, low energy consumption, little environmental pollution, and low cost, and is the realization of industrial production an ideal process.

Description

technical field [0001] The invention relates to a method for synthesizing p-bromopropiophenone. Background technique [0002] 4-Bromopropiophenone is an aromatic asymmetric ketone compound, white crystal, melting point is 45-47 ℃, 4-Bromopropiophenone is an important intermediate with structural composition. It is mainly used as a fine chemical raw material, and can also be used as a pharmaceutical intermediate to synthesize fine chemical products containing a p-bromobenzene ring structure in the molecule. [0003] The chemical name is: p-bromopropiophenone or 4-bromopropiophenone [0004] Molecular formula: C 9 h 9 BrO; molecular weight: 168.5; molecular structure: [0005] Physical and chemical properties: Appearance is white crystal, melting point mp: 45-47°C, boiling point bp: 265.5°C. [0006] Though p-bromopropiophenone has been used earlier, there is no report about the synthetic domestic literature of p-bromopropiophenone. According to the structure of p-bromo...

Claims

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Application Information

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IPC IPC(8): C07C49/807C07C45/48
Inventor 李建华王树清华平朱国华施磊
Owner NANTONG UNIVERSITY
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