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A kind of method for preparing methyl heptenone by prenaldehyde

A technology for methyl heptenone and prenyl aldehyde, applied in the field of preparing methyl heptenone, can solve the problems of complicated separation and purification and raw material recovery processes, large equipment corrosion and environmental pollution, poor atom economy and the like, and achieves production The effect of low cost, low price and low three waste discharge

Active Publication Date: 2017-03-22
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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  • A kind of method for preparing methyl heptenone by prenaldehyde
  • A kind of method for preparing methyl heptenone by prenaldehyde
  • A kind of method for preparing methyl heptenone by prenaldehyde

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0047] Example 1 A method for preparing methylheptenone from isopentenal

[0048] Condensation step

[0049] (1) Preparation of solid catalyst

[0050] Using γ-alumina as the carrier, prepare NaOH / Al with a mass percentage of 10% NaOH by the equal volume impregnation method 2 O 3 The solid base catalyst is dried in an oven at 100-120°C for 24 hours, and calcined in a muffle furnace at 500°C for 3 hours.

[0051] (2) Add acetone and catalyst

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

[0053] (3) Add prenaldehyde dropwise

[0054] 110.0g isopentenal was added dropwise at 50°C, dripped for 1 hour, kept at 50°C, and continuously sampled to detect the content of the reaction solution. After 1.5h, the conversion rate of isopentenal was 99.2%, and the stirring was stopped.

[0055] (4) Separate the catalyst

[0056] After the temper...

Embodiment 2

[0068] Example 2 A method for preparing methylheptenone from isopentenal

[0069] Condensation step

[0070] (1) Preparation of solid catalyst

[0071] Using γ-alumina as the carrier, prepare NaOH / Al with a mass percentage of 15% NaOH by the equal volume impregnation method 2 O 3 The solid base catalyst is dried in an oven at 100-120°C for 24 hours, and calcined 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-necked flask with mechanical stirring and condenser, and add 10g of NaOH with 15% NaOH / Al by mass. 2 O 3 Solid base catalyst, mechanical stirring.

[0074] (3) Add prenaldehyde dropwise

[0075] 181.0g of prenaldehyde was added dropwise at 50°C, dripped for 1 hour, kept at 50°C, and continuously sampled to detect the content of the reaction solution. After 1.2h, the conversion rate of prenaldehyde was 99.5%, and the stirring was stopped.

[0076] (4) Separate the catalyst

[0077] After the temperature is ...

Embodiment 3

[0090] Example 3 A method for preparing methylheptenone from isopentenal

[0091] Condensation step

[0092] (1) Preparation of solid catalyst

[0093] Using γ-alumina as the carrier, the equal volume impregnation method prepares NaOH / Al with a mass percentage of 20% NaOH 2 O 3 The solid base catalyst is dried in an oven at 100-120°C for 24 hours, and calcined in a muffle furnace at 500°C for 3 hours.

[0094] (2) Add acetone and catalyst

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

[0096] (3) Add prenaldehyde dropwise

[0097] 100.0 g of prenaldehyde was added dropwise at 55°C for 0.5 hours, kept at 55°C, and continuously sampled to check the content of the reaction solution. After the temperature was kept for 2.0 hours, the conversion rate of prenaldehyde was 99.1%, and the stirring was stopped.

[0098] (4) Separate the catalyst

[0099]...

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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 specifically relates to a method for preparing methylheptenone from prenaldehyde. Background technique [0002] Methylheptenone, chemical name: 6-methyl-5hepten-2-one, is an important fine chemical intermediate and the main raw material for the industrial preparation of linalool, citral and ionone, the latter It can further prepare vitamin A, vitamin E and various flavors and fragrances. [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-La Roche company. This method uses acetylene and acetone as raw materials to first synthesize methyl butynol, which is then selectively reduced to enol, and then reacts with ethyl acetoacetate. Caroll reaction produces methyl heptenone. The synthesis process is as follo...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C49/203C07C45/73
CPCY02P20/582
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