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Process for producing 2-cyclopentene-1-one

A manufacturing method and technology of cyclopentene are applied in chemical instruments and methods, preparation of organic compounds, preparation of carbon-based compounds, etc., and can solve problems such as high boiling point and high price

Inactive Publication Date: 2006-12-13
MANAC
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, this method requires a large amount of polar solvent, and the N-alkylformanilide compound used as a solvent has problems of high price and high boiling point

Method used

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  • Process for producing 2-cyclopentene-1-one
  • Process for producing 2-cyclopentene-1-one
  • Process for producing 2-cyclopentene-1-one

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0039] To 2.2 parts by weight of N-methylpyrrolidone solvent, 0.01 parts by weight of lithium bromide monohydrate, 0.26 parts by weight of lithium carbonate, and 0.001 parts by weight of hydroquinone were added, and the temperature of the kettle was heated to 100°C. Thereto was added dropwise 1 part by weight of 2-bromocyclopentanone over 1 hour. After the dropwise addition was terminated, it was allowed to react for 1 hour, then the system was depressurized to 6.0-6.7 kPa, and the temperature of the kettle was distilled below 140° C. to obtain 2-cyclopenten-1-one with a yield of 58%.

Embodiment 2

[0041] To a mixed solvent of 1.1 parts by weight of N-methylpyrrolidone and 1.1 parts by weight of toluene, 0.26 parts by weight of lithium carbonate and 0.001 parts by weight of hydroquinone were added, and the temperature of the kettle was heated to 100°C. Thereto was added dropwise 1 part by weight of 2-bromocyclopentanone over 1 hour. After the dropwise addition was terminated, it was allowed to react for another 1 hour, then the system was depressurized to 6.0-6.7 kPa, concentrated at a kettle temperature below 70° C., and 90% of the toluene used was recovered. After concentration, reduce the pressure in the system to 6.0-6.7kPa, and distill at a kettle temperature below 140°C to obtain 2-cyclopenten-1-one with a yield of 51%.

Embodiment 3

[0043] To a mixed solvent of 1.1 parts by weight of N-methylpyrrolidone and 1.1 parts by weight of toluene, add 0.01 parts by weight of lithium bromide monohydrate, 0.26 parts by weight of lithium carbonate and 0.001 parts by weight of hydroquinone, and heat the temperature of the kettle to 100°C. Thereto was added dropwise 1 part by weight of 2-bromocyclopentanone over 1 hour. After the dropwise addition was terminated, it was allowed to react for another 1 hour, then the system was depressurized to 6.0-6.7 kPa, concentrated at a kettle temperature below 70° C., and 90% of the toluene used was recovered. After concentration, reduce the pressure in the system to 6.0-6.7kPa, and distill at the kettle temperature below 140°C to obtain 2-cyclopenten-1-one with a yield of 57%.

[0044] The effect of the invention

[0045] According to the present invention, it is possible to provide a method for producing 2-cyclopenten-1-one, which can efficiently synthesize the target 2-cyclopen...

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Abstract

A process for producing 2-cyclopenten-1-one which comprises the step of dehydrohalogenating a 2-halogenocyclopentanone represented by the general formula (1): (1) (wherein X represents halogeno) in the presence of a base in a solvent comprising an amide solvent having a boiling point of 180 to 240 DEG C. According to the process, the target 2-cyclopenten-1-one can be simply and efficiently synthesized and can be easily separated from the solvent and purified by distillation. The solvent can be made reusable by vacuum concentration.

Description

technical field [0001] The present invention relates to an improved production method of 2-cyclopenten-1-one that can be used as a raw material of various pharmaceuticals and functional materials. Background technique [0002] In the past, as a production method for producing 2-cyclopenten-1-one from 2-halocyclopentanone, it is known that 2-halogenated cyclopentanone is heated in N,N-diethylaniline to make it Methods of dehydrohalogenation ("Beilstein", 7, 49). However, the yield of this method is low, and 2-cyclopenten-1-one cannot be obtained. Furthermore, a method of dehydrohalogenating an α-halogenated carbonyl compound by reacting it with an acid or lithium ions in N,N-dimethylformamide is also generally known. However, it is reported that even if 2-chlorocyclopentanone is reacted with hydrochloric acid in N, N-dimethylformamide, the conversion rate is only 20% ("Bull.Soc.Chem.Belg." 89 , (1980), 1046). In addition, when these dehydrohalogenation reactions are carri...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C45/65C07C49/597
CPCC07C45/65
Inventor 寄高和美竹田宏纪内田真隆
Owner MANAC
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