Method for preparing methyl heptenone by using 3-methylcrotonaldehyde

A technology of methyl heptenone and prenyl aldehyde, which is applied in the field of preparation of methyl heptenone, can solve the problems of complicated separation and purification and raw material recovery process, equipment corrosion, large environmental pollution, and low conversion rate of raw materials, and achieves The effect of low production cost, low price and high molar yield

Active Publication Date: 2016-01-06
SHANDONG NHU PHARMA +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0015] (1) Low selectivity, poor atom economy, low product yield, and low conversion rate of raw materials;
[0016] (2) The existing method of synthesizing methyl heptenone by isobutylene requires high temperature and high pressure reaction, which requires high equipment;
[0017] (3) High production cost;
[0018] (4) The phase transfer catalyst used in the prior art is insoluble in the reaction system and mixed in the solid phase of the by-product after the reaction, which makes separation difficult and the use time is short;
[0019] (5) The separation, purification and raw material recovery process is complex; and the existing method for synthesizing methyl heptenone by isoprene method uses chlorine-containing compounds in the route, which causes great corrosion to equipment and environmental pollution

Method used

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  • Method for preparing methyl heptenone by using 3-methylcrotonaldehyde
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  • Method for preparing methyl heptenone by using 3-methylcrotonaldehyde

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0047] Embodiment 1 A method for preparing methyl heptenone by isopentenal

[0048] condensation step

[0049] (1) Preparation of solid catalyst

[0050] Using γ-alumina as a carrier, NaOH / Al with a mass percentage of NaOH of 10% was prepared by equal volume impregnation method 2 o 3 Solid base catalyst, dried in an oven at 100-120°C for 24 hours, and roasted in a muffle furnace at 500°C for 3 hours.

[0051] (2) Add acetone and catalyst

[0052] Add 150.0g of acetone to a 1000ml three-neck flask with mechanical stirring and a condenser, and add 10g of NaOH with a mass percentage of 10% NaOH / Al 2 o 3 Solid base catalyst, mechanical stirring.

[0053] (3) Drop prenaldehyde

[0054]Add 110.0 g prenaldehyde dropwise at 50°C for 1 hour, keep warm at 50°C, continuously take samples to check the content of the reaction solution, the conversion rate of prenaldehyde is 99.2% after 1.5 h, stop stirring.

[0055] (4) Separation of catalysts

[0056] After cooling down, the r...

Embodiment 2

[0068] Embodiment 2 A kind of method for preparing methyl heptenone by isopentenal

[0069] condensation step

[0070] (1) Preparation of solid catalyst

[0071] Using γ-alumina as a carrier, NaOH / Al with a mass percentage of NaOH of 15% was prepared by equal volume impregnation method 2 o 3 Solid base catalyst, dried in an oven at 100-120°C for 24 hours, and roasted in a muffle furnace at 500°C for 3 hours.

[0072] (2) Add acetone and catalyst

[0073] Add 150.0g of acetone to a 1000ml three-neck flask with mechanical stirring and a condenser, and add 10g of NaOH with a mass percentage of 15% NaOH / Al 2 o 3 Solid base catalyst, mechanical stirring.

[0074] (3) Drop prenaldehyde

[0075] Add 181.0 g prenaldehyde dropwise at 50°C for 1 hour, keep warm at 50°C, continuously take samples to check the content of the reaction solution, after 1.2 hours the conversion rate of prenaldehyde is 99.5%, stop stirring.

[0076] (4) Separation of catalysts

[0077] After cooli...

Embodiment 3

[0090] Embodiment 3 A kind of method that prepares methyl heptenone by isopentenal

[0091] condensation step

[0092] (1) Preparation of solid catalyst

[0093] Using γ-alumina as a carrier, NaOH / Al with a mass percentage of NaOH of 20% was prepared by equal volume impregnation method 2 o 3 Solid base catalyst, dried in an oven at 100-120°C for 24 hours, and roasted in a muffle furnace at 500°C for 3 hours.

[0094] (2) Add acetone and catalyst

[0095] Add 300.0g of acetone to a 1000ml three-neck flask with mechanical stirring and a condenser, and add 3g of NaOH with a mass percentage of 20% NaOH / Al 2 o 3 Solid base catalyst, mechanical stirring.

[0096] (3) Drop prenaldehyde

[0097] Add 100.0 g prenaldehyde dropwise at 55°C for 0.5 hours, keep warm at 55°C, continuously take samples to check the content of the reaction solution, after 2.0 h of heat preservation, the conversion rate of prenaldehyde is 99.1%, stop stirring.

[0098] (4) Separation of catalysts ...

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PUM

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Abstract

The invention provides a method for preparing methyl heptenone by using 3-methylcrotonaldehyde, which comprises the steps of condensation and selective reduction, wherein the step of condensation comprises the sub-steps of adding acetone and a catalyst, and dropwise adding 3-methylcrotonaldehyde; and the step of selective reduction comprises the sub-steps of adding materials and carrying out hydrogenation reaction; and the sub-step of adding materials, namely adding 1 part of methyl diheptenone, 0-10 parts of a solvent, and 0.001-0.05 part of transition metal Pd/Rh catalyst precursor compounds and diphosphine ligand compounds into a reaction kettle. According to the invention, through two-step reaction, the mole yield of the methyl diheptenone to 3-methylcrotonaldehyde is high, and the methyl heptenone product content reaches 98.0-98.7%; in the step of selective reduction, the conversion rate of methyl diheptenone is greater than or equal to 99.0%, and the selectivity reaches 90.8-94%; and in the step of condensation, the conversion rate of 3-methylcrotonaldehyde is 99.0%, and the mole yield of the methyl diheptenone to 3-methylcrotonaldehyde reaches 89.8-92.7%.

Description

technical field [0001] The invention belongs to the technical field of organic synthesis, and in particular relates to a method for preparing methyl heptenone from isopentenal. Background technique [0002] Methyl heptenone, chemical name: 6-methyl-5 hepten-2 ketone, is an important fine chemical intermediate and the main raw material for the industrial preparation of linalool, citral, ionone, the latter Vitamin A, vitamin E and various flavors and fragrances can be further prepared. [0003] The methods for synthesizing methylheptenone in the prior art mainly include acetylene-acetone method, isoprene method and isobutylene method. [0004] The acetylene acetone method was first industrialized by the Swiss F.Hoffmann-LaRoche company. This method uses acetylene and acetone as raw materials to first synthesize methyl butynol, which is then selectively reduced to enol, and then combined with ethyl acetoacetate through Caroll The reaction produces methyl heptenone. The synth...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C49/203C07C45/73
CPCY02P20/582C07C45/73C07C45/62C07C45/72
Inventor 马啸赵文乐马书召张相如周剑平鲁光银陈为超马龙
Owner SHANDONG NHU PHARMA
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