Preparation method of citral

A technology of citral and aldehyde diprenyl acetal, which is applied in the direction of preparation of organic compounds, preparation by hydrolysis, and chemical methods for reacting liquids and liquids, etc., and can solve the problems of reduced cracking reaction rate, long residence time, and corrosive Large and other problems, to achieve the effect of reduced residence time, fast reaction rate, and small liquid holding capacity

Active Publication Date: 2014-05-14
WANHUA CHEM GRP CO LTD +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The disadvantages of this patent are: 1. 3-methyl-2-butene-1-aldehyde di-isopentenyl acetal is used in a large amount; 2. The amount of phosphoric acid is small, the control is difficult, and it is difficult to carry out continuous production
[0010] 1. The side stream production fluid contains citral. Because citral is unstable under acidic conditions, it is prone to polymerization reaction, and the residence time is 5min-2h. If the reaction time is too long, the selectivity of the reaction will be affected;
[0011] 2. The content of citral and intermediates in the side stream production fluid is greatly affected by the catalyst concentration, pressure and temperature changes of the reaction device, and the composition of the reaction liquid is prone to fluctuations that affect the residence time of subsequent rearrangement reactions, resulting in low conversion rates of intermediates or Decreased selectivity of citral;
[0012] 3. Since the cleavage reaction of 3-methyl-2-butene-1-aldehyde di-prenyl acetal is a first-order reaction, if prenyl alcohol and prenyl isopentenyl ether reaction product canno...

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0078] The inner diameter of the thin-film cracking reactor is 50mm, the outer diameter is 60mm, and the height is 1m. The distance between the largest circle at the bottom of the liquid distributor of the thin-film cracking reactor and the inner wall of the reactor is 0.05mm, and the cone angle of the liquid distributor is 100 degrees. The ratio of the spherical radius of the liquid storage tank to the circular radius of the conical bottom of the liquid distributor is 0.45, and the through holes opened on the inner shell wall of the thin film cracking reactor are evenly distributed in a matrix, and the distance between each through hole is 0.5mm. 0.01mm. The film pyrolysis reactor carries out gas phase extraction and condensation, and then enters the reactive distillation tower. The inner diameter of the reactive distillation tower is 25mm, equipped with 1.5m Raschig ring packing, the effective number of plates is 25, and the feeding position is located at the 17th block tray...

Embodiment 2

[0080] The distance between the largest circle at the bottom of the liquid distributor of the film cracking reactor and the inner wall of the reactor is 1.55 mm, the cone angle of the liquid distributor is 90 degrees, the spherical radius of the hemispherical liquid storage tank and the radius of the cone bottom circle of the liquid distributor The ratio is 0.55, and the through-holes opened on the inner shell wall of the membrane cracking reactor are evenly distributed in a matrix, the distance between each through-hole is 5mm, and the diameter of the opening is 0.05mm. The other structures of the film cracking reactor are the same as in Example 1. The reactive distillation column is the same as in Example 1. First, heat the film cracking reactor to 150°C, then preheat the nitrogen gas 7 to 150°C and introduce it into the film cracking reactor. The nitrogen consumption is 5000ml / min. After the temperature of the device is stable, turn on the vacuum pump to reduce the system p...

Embodiment 3

[0082] The distance between the largest circle at the bottom of the liquid distributor of the film cracking reactor and the inner wall of the reactor is 0.8mm, the cone angle of the liquid distributor is 80 degrees, the spherical radius of the hemispherical liquid storage tank and the radius of the cone bottom circle of the liquid distributor The ratio is 0.7, and the through-holes opened on the inner shell wall of the membrane cracking reactor are evenly distributed in a matrix, the distance between each through-hole is 10mm, and the diameter of the opening is 2mm. The other structures of the film cracking reactor are the same as in Example 1. The reactive distillation column is the same as in Example 1. First, heat the film cracking reactor to 180°C, then preheat the nitrogen gas 7 to 180°C and introduce it into the film cracking reactor. The nitrogen consumption is 15000ml / min. After the temperature of the device is stable, turn on the vacuum pump to reduce the system press...

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Abstract

The invention discloses a preparation method of citral. The preparation method comprises the following steps: reacting 3-methyl-2-butene-1-aldehyde diisopentenyl acetal in a film cracking reactor with a nitrogen gas stripping function to obtain prenyl alcohol and prenyl isopentenyl ether, adding a mixture of the prenyl alcohol and the prenyl isopentenyl ether into a reactive rectifying tower, continuously extracting the prenyl alcohol from the top of the tower and continuously extracting from the citral from the bottom of the tower. According to the method, the residence time of an intermediate under high-temperature and acidic conditions can be remarkably shortened, byproducts are reduced, and the citral selection performance can be more than 98%.

Description

technical field [0001] The invention relates to a preparation method of citral. Background technique [0002] Citral exists in essential oils such as lemongrass oil and eucalyptus oil, and has a strong lemon aroma. It is widely used in the food industry and daily chemicals. More importantly, citral is the main raw material for the synthesis of ionone, and it is also an important raw material for the production of vitamin E, vitamin A, isophytol or β-citronone. A natural spice with broad application prospects. [0003] The synthesis methods of citral generally include the following: alcohol and aldehyde condensation, rearrangement method, dehydrolinalool direct rearrangement method, geraniol gas phase oxidation method, isoprene method, acetone method and nitrogen oxide method. [0004] Alcohol and aldehyde condensation and rearrangement method: This method first condenses prenyl alcohol and prenyl aldehyde to generate 3-methyl-2-butene-1-aldehyde di-prenyl acetal, and then ...

Claims

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Application Information

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IPC IPC(8): C07C47/21C07C45/67
CPCB01J14/00C07C29/10C07C41/28C07C45/513C07C45/67C07C47/21C07C43/15C07C33/03
Inventor 刘英俊张永振张红涛李鹏张旭周斌庞计昌黎源华卫琦
Owner WANHUA CHEM GRP CO LTD
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