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A kind of method of synthesizing 2-pentyl-2-cyclopentenone in one step

A technology of cyclopentenone and cyclopentenone, which is applied in the field of preparing 2-pentyl-2-cyclopentenone, can solve the problems of affecting the purity of the target product, the catalyst cannot be recovered, and the catalyst cost is high, so as to achieve low cost and high reaction rate. Prolonged time, high selectivity effect

Active Publication Date: 2019-07-23
SHANDONG NHU PHARMA
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

The process is long, and the yield of each step seems to be relatively high. In fact, the total step yield from n-pentanal or cyclopentanone to 2-pentyl-2-cyclopentenone is low; and the catalyst used in some processes Unable to recycle or apply mechanically to participate in the reaction, resulting in high catalyst cost and large amount of waste water; in the prior art, there is the generation of by-product 2-pentyl-2-cyclopentanone, which affects the purity of the target product

Method used

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  • A kind of method of synthesizing 2-pentyl-2-cyclopentenone in one step

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Experimental program
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Effect test

Embodiment 1

[0040] Embodiment 1 A kind of method of synthesizing 2-pentyl-2-cyclopentenone in one step

[0041] Include the following steps:

[0042] (1) Preparation of materials:

[0043] Add 250g of 1% NaOH aqueous solution, 2.86g of alumina containing 3.3%Pb and 5.5%Pd, and trimethyl iodide into a 1L high-pressure reactor equipped with a thermometer, pressure gauge, constant pressure dripping device and mechanical stirring Silane 1.69g, prepare the mixed solution of 86g n-valeraldehyde and 84g cyclopentanone.

[0044] (2) Condensation isomerization reaction

[0045] Replace the high-pressure reaction kettle with nitrogen for more than 3 times, then keep the nitrogen pressure at 0.01MPa, raise the temperature to 120°C, and control the pressure in the kettle to 0.5 MPa; and the mixed gas is continuously introduced (the volume ratio of nitrogen and hydrogen is 8), and the gas is continuously discharged from the exhaust port at the same time, the gas output speed is controlled at 3ml / mi...

Embodiment 2

[0050] Embodiment 2 A kind of method of synthesizing 2-pentyl-2-cyclopentenone in one step

[0051] Include the following steps:

[0052] (1) Preparation of materials:

[0053] Add 86g of 1% NaOH aqueous solution, 2.86g of alumina containing 3.3%Pb and 1.5%Pd, and tert-butyldimethyl Base iodosilane 1.03g, prepare the mixed solution of 86g n-valeraldehyde and 92.4g cyclopentanone.

[0054] (2) Condensation isomerization reaction

[0055]Replace the high-pressure reaction kettle with nitrogen for more than 3 times, then keep the nitrogen pressure at 0.01MPa, raise the temperature to 180°C, and control the pressure in the kettle to 0.8 through the pressure reducing valve (for exhaust) and the mixed gas valve (for gas supply) MPa, and the mixed gas is continuously introduced (the volume ratio of nitrogen and hydrogen is 6), and at the same time, the gas is continuously discharged from the exhaust port, and the gas output speed is controlled at 3ml / min. The device starts to add...

Embodiment 3

[0060] Embodiment 3 A kind of method of synthesizing 2-pentyl-2-cyclopentenone in one step

[0061] Include the following steps:

[0062] (1) Preparation of materials:

[0063] Add 200 g of 0.8% NaOH aqueous solution, 4.66 g of alumina containing 3.5% Pb and 5.2% Pd, and tert-butyldimethyl Base iodosilane 1.95g, prepare the mixed solution of 86g n-valeraldehyde and 126g cyclopentanone.

[0064] (2) Condensation isomerization reaction

[0065] Replace the high-pressure reaction kettle with nitrogen for more than 3 times, then keep the nitrogen pressure at 0.01MPa, raise the temperature to 140°C, and control the pressure inside the kettle to 0.3 MPa, and the mixed gas is continuously introduced (the volume ratio of nitrogen and hydrogen is 20), and the gas is continuously discharged from the exhaust port at the same time. The gas output speed is controlled at 3ml / min. The device starts to add the mixed solution of n-valeraldehyde and cyclopentanone at a constant speed, the d...

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Abstract

The invention provides a method for one-step synthesis of 2-amyl-2-cyclopentenone. The method is characterized by comprising the steps of dropwise adding a mixed solution of n-valeraldehyde and cyclopentanone to alkali liquor containing a composite catalyst in a mixed gas atmosphere, and synthesizing 2-amyl-2-cyclopentenone through one-step reaction, wherein the mixed gas is the mixed gas of nitrogen and hydrogen. According to the method, 2-amyl-2-cyclopentenone is synthesized through a one-step method, the total yield is high, the cost of raw materials and auxiliary materials is relatively low, the conversion rate of n-valeraldehyde is 99.4%-99.8%, the selectivity is 87.23%-90.68%, and the yield of 2-amyl-2-cyclopentenone is 87.05%-90.5%. The used composite catalyst can be applied for more than 25-40 times. According to the method, byproducts are few, the prepared product is high in purity, the generated wastewater is relatively less, and the environment is protected.

Description

technical field [0001] The invention relates to a method for preparing 2-pentyl-2-cyclopentenone. The 2-pentyl-2-cyclopentenone is used as an industrial product in organic synthesis and is an important perfume intermediate. Background technique [0002] 2-pentyl-2-cyclopentenone is carried out by addition reaction with dimethyl malonate and then the addition product is decarboxylated to obtain the fragrance methyl dihydrojasmonate with jasmine fragrance; by 2-pentyl - Hydrogenation of 2-cyclopentenone can obtain 2-pentyl-2-cyclopentanone, and then oxidation can obtain perfume δ-lactone. [0003] 2-Pentyl-2-cyclopentenone is mainly obtained by condensation, dehydration and isomerization of n-pentylaldehyde and cyclopentanone. Some enterprises produce 2-pentyl-2-cyclopentenone in three steps; some enterprises It is to combine condensation and dehydration in a one-step reaction, that is, n-pentanal and cyclopentanone plus some solvents and catalysts to obtain 2-pentylidene cyc...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C45/45C07C49/597
CPCC07C45/45C07C49/597
Inventor 陈亚君马啸俞晓江贺金坤毕鲁昌吴元元
Owner SHANDONG NHU PHARMA
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