Method for continuous synthesis of ligustral in fixed bed reactor

A technology of fixed bed reactor and privet aldehyde, which is applied in chemical instruments and methods, preparation of organic compounds, preparation of carbon-based compounds, etc., can solve problems such as reaction temperature, high pressure, acrolein polymerization, difficult temperature control, etc. Achieve the effect of avoiding polymerization, low pressure and avoiding violent reaction

Inactive Publication Date: 2019-02-01
SHANDONG NHU PHARMA
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0005] The reaction between 2-methyl-1,3-pentadiene and acrolein is an exothermic reaction. When the "one-pot" process is adopted, there are the following disadvantages: (1) The temperature is difficult to control, and it is easy to overheat, causing safety accidents ; (2) The reaction temperature and pressure of the "one pot method" process are high, which is easy to make acrolein self-polymerize, which is not conducive to the reaction; (3) At the same time, the "one pot method" process is an intermittent operation, and the production efficiency is low

Method used

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  • Method for continuous synthesis of ligustral in fixed bed reactor
  • Method for continuous synthesis of ligustral in fixed bed reactor
  • Method for continuous synthesis of ligustral in fixed bed reactor

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Embodiment 1

[0039] The method for continuously synthesizing privetal in a kind of fixed-bed reactor of embodiment 1

[0040] Include the following steps:

[0041] (1) Mixing of raw materials

[0042] 165.1g (2.01mol) 2-methyl-1,3-pentadiene and 114.9g (2.05mol) acrolein are mixed, and the molar ratio of 2-methyl-1,3-pentadiene and acrolein in the mixture is 1:1.02, put the mixed solution in the raw material solution 1 storage tank.

[0043] (2) Air replacement, preheating

[0044]The fixed-bed reactor 4 passes nitrogen from the nitrogen buffer tank 3 to replace the air, and the temperature is raised for preheating.

[0045] (3) Continuous response

[0046] When the temperature of the catalyst bed in the reactor reaches the reaction temperature, feed the raw material liquid 1 into the reactor through the double-plunger micrometering pump 2, and fill the fixed bed reactor 4 with phosphomolybdic acid modified Al 2 o 3 Catalyst, catalyst loading is 15g, reaction temperature is 36°C, rea...

Embodiment 2

[0049] The method for continuously synthesizing privetal in a kind of fixed-bed reactor of embodiment 2

[0050] Include the following steps:

[0051] (1) Mixing of raw materials

[0052] 165.1g (2.01mol) 2-methyl-1,3-pentadiene and 129.6g (2.31mol) acrolein are mixed, and the molar ratio of 2-methyl-1,3-pentadiene and acrolein in the mixture is 1:1.15, put the mixed solution in the raw material solution 1 storage tank.

[0053] (2) Air replacement, preheating

[0054] The fixed-bed reactor 4 passes nitrogen from the nitrogen buffer tank 3 to replace the air, and the temperature is raised for preheating.

[0055] (3) Continuous response

[0056] When the temperature of the catalyst bed in the reactor reaches the reaction temperature, feed the raw material liquid 1 into the reactor through the double-plunger micrometering pump 2, and fill the fixed bed reactor 4 with phosphomolybdic acid modified Al 2 o 3 Catalyst, catalyst loading is 20g, reaction temperature is 40°C, re...

Embodiment 3

[0059] The method for continuously synthesizing privetal in a kind of fixed-bed reactor of embodiment 3

[0060] Include the following steps:

[0061] (1) Mixing of raw materials

[0062] 165.1g (2.01mol) 2-methyl-1,3-pentadiene and 123.9g (2.21mol) acrolein are mixed, and the molar ratio of 2-methyl-1,3-pentadiene and acrolein in the mixture is 1:1.10, put the mixed solution in the raw material solution 1 storage tank.

[0063] (2) Air replacement, preheating

[0064] The fixed-bed reactor 4 passes nitrogen from the nitrogen buffer tank 3 to replace the air, and the temperature is raised for preheating.

[0065] (3) Continuous response

[0066] When the temperature of the catalyst bed in the reactor reaches the reaction temperature, feed the raw material liquid 1 into the reactor through the double plunger micro metering pump 2, and fill the fixed bed reactor 4 with phosphotungstic acid modified Al 2 o 3 Catalyst, catalyst loading is 20g, reaction temperature is 40°C, r...

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Abstract

The invention provides a method for continuous synthesis of ligustral in a fixed bed reactor. The method is characterized by including raw material mixing and continuous reaction. The method providedby the invention adopts a modified Al2O3 catalyst to catalyze reaction, has low reaction temperature and pressure, effectively avoids the polymerization of acrolein in reaction raw materials, reducesenergy consumption, improves the utilization of raw materials, at the same time avoids the situation of severe reaction and difficult control of reaction temperature in one-pot process, and has high safety factor. The pure ligustral product prepared by the method provided by the invention has a content of 99.5%-99.7%, wherein the content of isomer I is 78.1-78.9%, the content of isomer II is 20.7-21.4%, the conversion rate of 2-methyl-1, 3-pentadiene in the process is 98.3-99.1%, and the product selectivity is 97.0-98.4%, and in terms of 2-methyl-1, 3-pentadiene, the yield of the reaction process is 95.4-97.0%.

Description

technical field [0001] The invention relates to the field of fine chemical industry, in particular to a method for continuously synthesizing privetal in a fixed-bed reactor. Background technique [0002] Privetaldehyde, the molecular formula is C 9 h 14 O is a mixture of two isomers of 2,4-dimethyl-3-cyclohexenecarbaldehyde (I) and 3,5-dimethyl-3-cyclohexenecarbaldehyde (II). Construct ratio (I): (II) = 4:1. The pure product of privet aldehyde is a colorless or light yellow liquid, which is widely used in the fragrance of the fragrance. [0003] At present, the method for synthesizing privetal is mainly to prepare 2-methyl-1,3-pentadiene and acrolein through Diels-Alder reaction. In the existing literature, Diels-Alder reaction synthesis of privet aldehyde is carried out by "one-pot method", that is, a certain proportion of 2-methyl-1,3-pentadiene and acrolein are respectively added to the reactor, and the reactor is filled with Nitrogen to a certain pressure, heat pres...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C45/69C07C47/42
CPCC07C45/69C07C2601/16C07C47/42
Inventor 马啸包新军邱金倬李孟杰范乃强李焕鹏李耀林林波孙孝晖李国庆
Owner SHANDONG NHU PHARMA
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