Preparation method of optically active citronellal

A technology for optically active and optically active ligands is applied in the field of preparing optically active citronellal, and can solve the problems of reduced catalyst conversion frequency, complex process operation, low hydrogenation efficiency and the like

Pending Publication Date: 2020-03-10
WANHUA CHEM GRP CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0006] The method reported above has the advantages of high chemoselectivity and stereoselectivity, but the homogeneous transition metal catalysts prepared by transition metal compounds and chiral ligands have the disadvantage of low hydrogenation efficiency, especially at high molar ratios of substrate/ Under the conditions of the cata

Method used

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  • Preparation method of optically active citronellal
  • Preparation method of optically active citronellal
  • Preparation method of optically active citronellal

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Experimental program
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Embodiment 1

[0065] Embodiment 1 (substrate raw material pretreatment)

[0066] The rectification column used for rectification and purification of neral and geranial aldehyde is composed of a vacuum jacketed rectification column with a length of 1 meter and an inner diameter of 50 mm. There is a triangular spiral random packing with a diameter of 1.5 mm inside. Decalin is used In the separation efficiency measurement of the mixture of cis-trans isomers (the molar ratio of cis-trans isomers is 1:1) under the top pressure of 1000Pa, the separation efficiency of the whole column was measured to be 41 theoretical plates. The tower is equipped with an oil-heated thin-film evaporator (the evaporation area is 0.07m 2 ) and a condenser cooled with cooling water.

[0067] Under the top pressure of 1000Pa, carry out batch rectification to 500g purity 99% neral, the heating temperature of the thin film evaporator at the bottom of the tower is 100 ℃, and the top condenser temperature is 20 ℃. After...

Embodiment 2

[0068] Embodiment 2 (substrate raw material pretreatment)

[0069] Use the rectifying tower described in embodiment 1, under the top pressure of 1000Pa, 500g purity is 99% geranial aldehyde is carried out intermittent rectification, the heating temperature of the thin-film evaporator at the bottom of the tower is 100 ℃, the top condenser temperature is 20°C. After total reflux for 1 hour to establish tower balance, adjust the reflux ratio to be 100:1 to carry out tower top extraction, switch to the geranial product collection tank after extracting 80g of the front fraction at the top of the tower, stop rectification after continuous extraction of 380g, and rectify to obtain The measured hydroxyl value of geranial is 1mgKOH / g, and the iron content is 60ppm.

Embodiment 3

[0070] Embodiment 3 (substrate raw material pretreatment)

[0071]Using the rectifying tower described in embodiment 1, under the top pressure of 1000Pa, 500g purity is carried out intermittent rectification to the neral aldehyde of 99%; is 20°C. After total reflux for 1 hour to establish tower balance, adjust the reflux ratio to be 150:1 to carry out tower top extraction, switch to the neral product collection tank after extracting 100g of the front fraction at the top of the tower, stop rectification after continuous extraction of 350g, and rectify to obtain The measured hydroxyl value of neral aldehyde is 1mgKOH / g, and the iron content is 60ppm.

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Abstract

The invention provides a preparation method of optically active citronellal, which can obviously enhance the catalytic stability of an optically active transition metal catalyst for asymmetric hydrogenation for homogeneous catalysis, thereby implementing higher turnover number. In the preparation method of the optically active citronellal, a substrate is subjected to an asymmetric hydrogenation reaction in the presence of the transition metal catalyst to generate the optically active citronellal, and the transition metal catalyst is obtained by reacting a transition metal compound with an optically active ligand containing two phosphorus atoms, wherein the substrate raw material is one or a combination of two of neral and geranial, and the hydroxyl value in the substrate raw material for the asymmetric hydrogenation reaction is controlled to be less than or equal to 6mgKOH/g and/or the iron content is controlled to be less than or equal to 50ppm.

Description

technical field [0001] The invention relates to a method for preparing optically active citronellal, in particular to a method for preparing optically active citronellal, especially R-citronellal, by asymmetrically hydrogenating neral and / or geranial. 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 the homogeneous catalytic hydrogenation of α,β-unsaturated aldehydes and used this method t...

Claims

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Application Information

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IPC IPC(8): C07C45/62C07C47/21C07C45/82
CPCC07C45/62C07C45/82C07B2200/07
Inventor 董菁于磊张永振黎源
Owner WANHUA CHEM GRP CO LTD
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