Citral with low color number and preparation method thereof

A technology of citral and color number, which is used in the preparation of carbon-based compounds, chemical instruments and methods, preparation of organic compounds, etc.

Active Publication Date: 2021-03-30
WANHUA CHEM GRP CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0007] The citral obtained by the above-mentioned prior art is all light yellow or dark yellow, and

Method used

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  • Citral with low color number and preparation method thereof
  • Citral with low color number and preparation method thereof
  • Citral with low color number and preparation method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0045] Embodiment 1 (preparation of thick citral)

[0046] Add 774g prenol (about 9mol), 84g prenaldehyde (about 1mol) and 1.15g phosphoric acid (mass content 85%, about 0.01mol) into the bottom of the rectification column, the number of theoretical plates of the rectification column is 9 , the temperature at the bottom of the tower is 110°C, the vacuum at the top of the tower is 5KPa, and the reflux ratio is 1:10. Prenyl alcohol and water are extracted at the top of the tower. After heating the tower kettle for 5 hours, when there is almost no reflux at the top of the tower, stop heating. The product obtained in the tower kettle is isopentenyl prenyl aldehyde, and the acetal content is 99% as detected by the gas phase. Add 0.79g of pyridine (about 0.01mol) into the still of the rectification tower, raise the temperature of the still to 150°C, the vacuum at the top of the tower is 2KPa, the reflux ratio is 1:3, and the cis / trans-iso Pentenyl-3-methylbutadiene ether and prenol...

Embodiment 2

[0048] Embodiment 2 (the reduction of citral color number)

[0049] The thick citral that makes among the embodiment 1 first uses diameter 50mm, high 1m, the CO that theoretical plate number is 30 plates2 Stripping tower for stripping treatment. CO 2 The stripping tower is operated under the condition of normal pressure and 20°C, the crude citral is added from the upper part of the tower, and the CO2 added in the lower part of the tower 2 Countercurrent contact in column, CO 2 The ratio of volume flow rate to citral is 20:1, the residence time of the liquid phase in the tower is 10min, and the crude citral product after air stripping is continuously extracted from the bottom of the tower.

[0050] The triarylphosphine compound (II) Added to the above-mentioned crude citral product after air stripping, the addition amount of triarylphosphine compound (II) is 0.02wt% of the crude citral product quality through air stripping, after mixing uniformly, enter the rectification to...

Embodiment 3

[0051] Embodiment 3 (the reduction of citral color number)

[0052] The thick citral that makes among the embodiment 1 first uses diameter 50mm, high 1m, the CO that theoretical plate number is 20 plates 2 Stripping tower for stripping treatment. CO 2 The stripping tower is operated under the condition of normal pressure and 25°C, the crude citral is added from the upper part of the tower, and the CO2 added in the lower part of the tower 2 Countercurrent contact in column, CO 2 The ratio of volume flow rate to citral is 50:1, the residence time of the liquid phase in the tower is 30min, and the crude citral product after air stripping is continuously extracted from the bottom of the tower.

[0053] The triarylphosphine compound (III) Added to the above-mentioned crude citral product after air stripping, the addition amount of triarylphosphine compound (III) is 0.04wt% of the crude citral product quality through air stripping, after mixing uniformly, enter the rectificatio...

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Abstract

The invention provides citral with a low color number and a preparation method thereof. The method comprises the following steps: (1) carrying out countercurrent contact on CO2 and a crude citral stream in a gas stripping tower; and (2) conducting rectifying in the presence of a triarylphosphine compound to obtain a citral product with a low color number. The structural formula of the triarylphosphine compound is shown as a formula (I) in the specification. In the formula (I), R is a hydroxyl, carboxyl or aldehyde group, and R is at the ortho-position, meta-position or para-position of a P atom. The citral product treated by using the method provided by the invention has a lower color number and purer smell.

Description

technical field [0001] The invention relates to citral, in particular to a post-treatment method for crude citral, and more particularly to a low-color citral and a preparation method thereof. Background technique [0002] Citral, also known as 2,6-dimethyl-2,6-octadienal, naturally exists in plant essential oils such as lemongrass oil and eucalyptus oil. It has a strong lemon aroma and is a commonly used spice product , can be directly added to soft drinks, candies and baked goods, and can also be used to prepare various flavors, especially in citrus flavors, which are indispensable in the perfume industry. In addition, citral is still more It is the raw material of fine chemicals, and its downstream products include vitamin A, ionone, precious spices, etc. [0003] 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. The elimination reaction is one o...

Claims

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Application Information

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IPC IPC(8): C07C45/78C07C45/82C07C45/86C07C47/21
CPCC07C45/78C07C45/783C07C45/82C07C45/86C07C47/21Y02P20/54
Inventor 于斌成李瑞雪杨士华王联防董菁
Owner WANHUA CHEM GRP CO LTD
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