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Method for preparing bromopentoic acid

A technology of brovaleric acid and hydrogen bromide, applied in the preparation of carboxylate/lactone, organic chemistry, etc., can solve the problems of difficult process, inability to carry out industrial production, high material concentration, etc., and achieves simple process and easy to form scale The effect of chemical production and wide application prospects

Inactive Publication Date: 2006-04-12
FUDAN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The disadvantage of this method is that no organic solvent is used, the concentration of the material in the system is too high, and it is difficult to stir, and the remaining part of the raw material δ-valerolactone is not easy to consume and remains in the system
It is difficult to obtain high-purity product 5-bromovaleric acid, which cannot meet the high-purity requirements of the modern pharmaceutical industry for raw materials
Therefore, this method also has technical difficulties
[0010] G.L.Kad's method uses a microwave reactor, which is only used for research and cannot be industrialized at all
Therefore, this method has no use value in industry

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0017] Embodiment 1: in the three-necked bottle of 500 milliliters, install thermometer, stirrer, add raw material δ-valerolactone (1 mole, 100 grams), normal hexane (200 milliliters), start to stir then. Dry hydrogen bromide gas (1.1 mol, 89 g) was introduced, and the reaction temperature was controlled at 20°C to 30°C. After completion of the hydrogen bromide gas sparging, the mixture was stirred at this temperature for an additional 5 hours. Then cool to 0~10°C and stir for 3 hours, a large amount of crystals are formed. After filtration, a light yellow 5-bromovaleric acid solid was obtained, weighing 176 grams, with a yield of 97% and a purity of 99.5% (gas chromatography analysis).

Embodiment 2

[0018] Embodiment 2: in the three-necked flask of 500 milliliters, install thermometer, stirrer, add raw material δ-valerolactone (1 mole, 100 grams), hexanaphthene (200 milliliters), start to stir then. Dry hydrogen bromide gas (1.2 mol, 97 g) was introduced, and the reaction temperature was controlled at 30°C~40°C. After completion of the hydrogen bromide gas sparging, it was stirred at this temperature for an additional 4 hours. Then cool to 5~15°C and stir for 2 hours, a large amount of crystals are formed. After filtration, a light yellow solid of 5-bromovaleric acid was obtained, weighing 178 grams, with a yield of 98% and a purity of 99.2% (gas chromatography analysis).

Embodiment 3

[0019] Embodiment 3: in the three-necked bottle of 500 milliliters, install thermometer, stirrer, add raw material δ-valerolactone (1 mole, 100 grams), toluene (200 milliliters), begin to stir then. Dry hydrogen bromide gas (1.5 mol, 121 g) was introduced, and the reaction temperature was controlled at 40°C~50°C. After completion of the hydrogen bromide gas sparging, the mixture was stirred at this temperature for an additional 6 hours. Then cool to 10~20°C and stir for 4 hours, a large amount of crystals are formed. After filtration, a light yellow 5-bromovaleric acid solid was obtained, weighing 164 grams, with a yield of 97% and a purity of 99.1% (gas chromatography analysis).

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PUM

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Abstract

This invention relates to a manufacturing technique of organic compounds, or a preparation method for 5-bromo-valeric acid. Based on the method dry hydrogen bromide gas is going through a delta-valerolactone containing organic solvent, the ring of delta-valerolactone is easy to have cleavage reaction, corresponding 5-bromo-valeric acid is produced with high yield. As 5-bromo-valeric acid is hard to dissolve in alkanes, cycloalkanes and aromatic compounds solvents, cooling it below 30 DEG C, lower than the melting point of 5-bromo-valeric acid, 5-bromo-valeric acid crystallized and deposited. Then, 5-bromo-valeric acid solid with high purity is separated through filtration technique. This method has simple technique, easy to form scaled production, with wide application prospect and good economic benefit.

Description

technical field [0001] The invention belongs to the technical field of organic compound production, in particular to a preparation method of 5-bromovaleric acid. Background technique [0002] 5-Bromopentanoic acid is a very important pharmaceutical intermediate, widely used in the manufacture of medicine and veterinary medicine. At present, there is no domestic manufacturer producing it. The reason is that it is difficult to obtain high-purity products due to insufficient technology. Since the melting point of 5-bromovaleric acid is low, that is, the melting point is 38-40°C, it is not easy to form crystals, and 5-bromovaleric acid is generally obtained by distillation. However, in the presence of water, 5-bromovaleric acid is easily dehydrobrominated by cyclization to δ-valerolactone. Therefore, in the distillation process, a part of 5-bromovaleric acid reacts with water in the system to become raw material δ-valerolactone, and this process is difficult to obtain high-pur...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C51/09C07C53/19
Inventor 刘国斌
Owner FUDAN UNIV
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