Method for preparing optically active citronellal and catalyst system for method

An optically active, citronellal technology, applied in the direction of physical/chemical process catalysts, organic chemical methods, chemical instruments and methods, etc., can solve the problems that cannot be directly satisfied, and the optical selectivity is not high.

Active Publication Date: 2020-04-24
WANHUA CHEM GRP CO LTD
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0008] The method reported above has high chemoselectivity and catalyst activity, showing a certain potential for industrial application. However, due to the low optical selectivity, the optical purity of the obtained R-citronellal is less than 95ee%, which cannot directly meet the downstream requirements. Especially the demand for raw materials for the synthesis of L-menthol

Method used

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  • Method for preparing optically active citronellal and catalyst system for method
  • Method for preparing optically active citronellal and catalyst system for method
  • Method for preparing optically active citronellal and catalyst system for method

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0061] Embodiment 1 (loaded TiO 2 Preparation of activated carbon)

[0062] Weigh 5 g of activated carbon, wash it three times with distilled water, dehydrate it in a vacuum oven at a constant temperature of 100° C. for 12 hours, and set aside. Take 24 mL of absolute ethanol, add a small amount of nitric acid dropwise to adjust the pH to 3.5, measure 3 mL of tetra-n-butyl titanate, and drop it into the absolute ethanol solution while stirring. Add the above 5g of 10-20 mesh activated carbon into the above system, stir vigorously for 20min, measure 5mL of distilled water and 13mL of absolute ethanol respectively to make a mixed solution, control the titration rate to 30d / min, slowly drop into the reaction mixture under constant stirring In the system, the stirring was continued for 10 min and left to stand to obtain a black sol. The obtained gel was placed in a constant temperature drying oven at 600°C for 12 hours to slowly evaporate the absolute ethanol in the colloid. Aft...

Embodiment 2

[0063] Embodiment 2 (loaded TiO 2 Preparation of activated carbon)

[0064] Weigh 5 g of activated carbon, wash it three times with distilled water, dehydrate it in a vacuum oven at a constant temperature of 100° C. for 12 hours, and set aside. Take 24 mL of absolute ethanol, add a small amount of nitric acid dropwise to adjust the pH to 3.5, measure 6 mL of tetra-n-butyl titanate, and drop it into the absolute ethanol solution while stirring. Add the above 5g of 10-20 mesh activated carbon into the above system, stir vigorously for 20min, measure 5mL of distilled water and 13mL of absolute ethanol respectively to make a mixed solution, control the titration rate to 30d / min, and slowly drop into the reaction system under constant stirring , continue to stir for 10 min, and stand still to obtain a black sol. The obtained gel was placed in a constant temperature drying oven at 600°C for 12 hours to slowly evaporate the absolute ethanol in the colloid. After drying, it was gro...

Embodiment 3

[0065] Embodiment 3 (loaded TiO 2 Preparation of activated carbon)

[0066] Weigh 5 g of activated carbon, wash it three times with distilled water, dehydrate it in a vacuum oven at a constant temperature of 100° C. for 12 hours, and set aside. Take 24 mL of absolute ethanol, add a small amount of nitric acid dropwise to adjust the pH to 3.5, measure 6 mL of tetra-n-butyl titanate, and drop it into the absolute ethanol solution while stirring. Add the above 5g of 20-30 mesh activated carbon into the above system, stir vigorously for 20min, measure 5mL of distilled water and 13mL of absolute ethanol respectively to make a mixed solution, control the titration rate to 30d / min, and slowly drop into the reaction system under constant stirring , continue to stir for 10 min, and stand still to obtain a black sol. The obtained gel was placed in a constant temperature drying oven at 600°C for 12 hours to slowly evaporate the absolute ethanol in the colloid. After drying, grind it w...

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Abstract

The invention provides a method for preparing optically active citronellal and a catalyst system for the method. The method comprises the step that in the presence of a catalyst, neryl aldehyde shownin the formula (I) and / or geranial shown in the formula (II) are / is subjected to asymmetric hydrogenation to prepare optically active R-citronellal shown in the formula (III), and the catalyst comprises rhodium serving as a catalytic activity transition metal, a chiral bidentate diphosphine ligand and TiO2-loaded activated carbon. According to the method, the stereoselectivity of the reaction canbe remarkably improved, and the R-citronellal with high optical purity is obtained.

Description

technical field [0001] The invention relates to a method for preparing optically active citronellal and a catalyst system used in the method, in particular to an asymmetric hydrogenation of neral and / or geranial to prepare optically active citronellal, especially R-citronellal Process for fural and catalyst system for use in the process. Background technique [0002] Citronellal is an important fragrance ingredient, widely used in the flavoring and preparation of beverages, candies, food, etc. It is also an important intermediate compound, especially optically active citronellal is an important intermediate used to synthesize L-menthol. [0003] EP 0000315 discloses a process for the preparation of optically active R-citronellal by hydrogenating geranial or neral in the presence of a catalyst complex dissolved in the reaction system and consisting of rhodium and a chiral phosphine composition. [0004] J.Mol.Cat.16(1982)51-59 and Helv.Chim.Acta.84(2001)230-242 reported th...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C45/62C07C47/21B01J31/38B01J31/24
CPCC07C45/62B01J31/24B01J31/38B01J31/2414B01J31/2457B01J2531/0213B01J2531/822B01J2231/32C07B2200/07C07C47/21
Inventor 方文娟薛勇勇董菁张永振陈志刚刘文妮黎源
Owner WANHUA CHEM GRP CO LTD
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