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Preparation method of citral

A technology of citral and aldehyde diprenyl acetal, which is applied in the field of citral preparation, can solve the problems of long residence time, heavy component generation, and increased production energy consumption, so as to shorten the reaction time and make full use of energy , The effect of improving product yield

Active Publication Date: 2018-06-05
WANHUA CHEM GRP CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] But above method still has defect: 1, reaction residence time is longer, and heavy component generates more; 2, although select phosphoric acid as catalyst for use, scrap rate is still up to 3.6% or even more; , an acidic environment is formed, and a large amount of heavy components are produced in the heating process of the subsequent separation tower liquid, which is difficult to separate; 4. Prenyl alcohol cannot be directly separated from the ether intermediate, and the secondary separation increases the production energy consumption

Method used

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  • Preparation method of citral

Examples

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Effect test

Embodiment 1

[0029] Add 0.0718g of triethylaluminum to the flash tank, raise the temperature of the flash tank to 150°C, replace it with 0.5MPa carbon dioxide gas for 5 times, then press the flash tank to 3MPa with carbon dioxide gas, and keep the pressure with the back pressure valve. Add 238g of prenyl diprenyl acetal to the autoclave, use 0.5MPa carbon dioxide gas to replace it 5 times, feed carbon dioxide into the autoclave until the absolute pressure reaches 8MPa and raise the temperature to 150°C to start thermal cracking Reaction, after reacting for 20 minutes, open the discharge port of the reactor, so that all the thermal cracking reaction products enter the flash tank through the mass flow meter, the flow rate is 30g / min, close the discharge port of the reactor after feeding, and start the rearrangement reaction Timing, after observing that there is no obvious fluctuation in the back pressure gauge of the flash tank, continue the reaction, and the total reaction time of flash evap...

Embodiment 2

[0032] Add 0.00714g of tripropylaluminum to the flash tank, raise the temperature of the flash tank to 120°C, replace it with 0.5MPa ethane gas for 5 times, then press the flash tank to 10MPa with ethane gas, and keep the pressure with the back pressure valve . Add 238g of prenyl diisopropenyl acetal into the autoclave, replace it with 0.5MPa ethane gas for 5 times, feed ethane into the autoclave until the absolute pressure reaches 0.5MPa and raise the temperature to 200°C, start Thermal cracking reaction, after reacting for 5 minutes, open the discharge port of the reactor, so that all the thermal cracking reaction products enter the flash tank through the mass flow meter, the flow rate is 30g / min, close the discharge port of the reactor after feeding, and start to re- Arrange the reaction timing, observe that there is no obvious fluctuation in the back pressure gauge of the flash tank, then continue the reaction, the total reaction time of flash evaporation and rearrangement...

Embodiment 3

[0035] Add 0.710g of aluminum hydride to the flash tank, raise the temperature of the flash tank to 180°C, replace it with 0.5MPa carbon dioxide gas for 5 times, then press the flash tank to 5MPa with carbon dioxide gas, and keep the pressure with the back pressure valve. Add 238g of prenyl diprenyl acetal to the autoclave, use 0.5MPa carbon dioxide gas to replace 5 times, pass carbon dioxide into the autoclave until the absolute pressure reaches 20MPa and raise the temperature to 120°C to start thermal cracking Reaction, after reacting for 40 minutes, open the discharge port of the reactor, so that all the thermal cracking reaction products enter the flash tank through the mass flow meter, the flow rate is 30g / min, close the discharge port of the reactor after feeding, and start the rearrangement reaction Timing, after observing that there is no obvious fluctuation in the back pressure gauge of the flash tank, continue the reaction, and the total reaction time of flash evapora...

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Abstract

The invention provides a preparation method of citral. The method comprises the following steps: in a supercritical condition, carrying out thermal cracking reaction on one or more of isoprenaldehydediisobutenol, isoprenaldehyde diisopentenol and isoprenaldehyde diisopentenol as raw materials to obtain cis / trans-isopentenyl-3-methyl-butadiene; and carrying out Claisen rearrangement and Cope rearrangement on the cis / trans-isopentenyl-3-methyl-butadiene to obtain the citral. The method provided by the invention is characterized in that the thermal cracking process is carried out in the supercritical condition, the cis / trans-isopentenyl-3-methyl-butadiene is separated in a flash manner, and a trialkyl aluminum catalyst is introduced in a flash tank to direct rearrange the cis / trans-isopentenyl-3-methyl-butadiene in the flash process to obtain the citral, so that the reaction time is shortened greatly and the product yield is increased.

Description

technical field [0001] The invention belongs to the field of organic synthesis, and in particular relates to a preparation method of citral. Background technique [0002] Citral is not only a commonly used spice product itself, but also can be used as a raw material for various fine chemicals, and its downstream products include vitamins, precious spices, etc. At present, the global demand for citral is huge, and natural citral is far from being able to meet the demand. Chemical synthesis of citral has become particularly important. In the citral synthesis route, cis / trans isopentenyl-3-methylbutanedi The synthesis of enyl ethers is a crucial step. [0003] In 2011, Zhejiang NHUCheng published in Chemical Industry Times "Research on Cis-Trans-Prenyl-3-Methyl Butadiene Ether" in the thermal cracking process of benzoic acid, phosphoric acid, nitric acid, sulfuric acid A large number of screening experiments were carried out on various catalysts, and phosphoric acid with a co...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C45/67C07C47/21
CPCC07C41/28C07C45/513C07C45/67C07C47/21C07C43/16Y02P20/54
Inventor 蔺海政鲍元野张永振黎源
Owner WANHUA CHEM GRP CO LTD
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