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Method for preparing optically active citronellal, and catalyst used in method

An optically active, citronellal technology, used in physical/chemical process catalysts, organic chemistry methods, chemical instruments and methods, etc., can solve problems such as complex process operations

Active Publication Date: 2020-04-14
WANHUA CHEM GRP CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

The process described by this inventor allows it to operate either at once or more frequently without stopping down its work flow entirely due to technical limitations such as equipment size constraints that may limit productivity. This makes it ideal for large scale manufacturing purposes where there are many different types of products being produced simultaneously on one machine.

Problems solved by technology

This patented describes different methods for producing Optically Activable Chemicals (OCA) from specific types of molecules called Grignardals. These techniques involve reacting certain chemical substances together under special conditions such that they can form new products while minimizing their harmful effects on human health. However, these processes are expensive due to the time required for carrying out complicated steps involved during manufacturing. There needs to develop a simpler way to make OCAs efficiently at commercial levels.

Method used

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  • Method for preparing optically active citronellal, and catalyst used in method
  • Method for preparing optically active citronellal, and catalyst used in method
  • Method for preparing optically active citronellal, and catalyst used in method

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Experimental program
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Effect test

Embodiment 1

[0058] Under nitrogen atmosphere, 7.5mg Rh(CO) 2 acac (0.029mmol) and 18.6mg (R,R)-chiraphos (0.0436mmol) were dissolved in 50g toluene to obtain a solution, and 6g of 100-200 mesh basic alumina was added to the above-obtained solution under stirring, and transferred into an autoclave purged with nitrogen. Add 600g of neral aldehyde (the ratio of neral / geranial double bond isomers=99:1; based on the rhodium atom in the catalyst, the ratio of substrate / catalyst=135789) into the reactor, at 25°C After stirring for 2 hours, the reaction pressure was adjusted to 5MPa by injecting hydrogen, and the temperature was raised to 60° C. for 5 hours. The yield was 95% as measured by gas chromatography, and the yield of R-citronellal with an optical purity of 88ee% was 94%.

[0059] Based on R-citronellal and Rh(CO) 2 The turnover number for the entire reaction of acac is 127642.

Embodiment 2-4

[0061] Under nitrogen atmosphere, 7.5mg Rh(CO) 2 acac (0.029mmol) and 6.5mg (S,S)-chiraphos (0.0152mmol) were dissolved in 50g toluene to obtain a solution, and 0.2g of basic alumina was added to the solution obtained above under stirring, and it was transferred to the in a replaced autoclave. 441.8g of geranial (the ratio of geranial / neral double bond isomers=99:1; in terms of rhodium atoms in the catalyst, substrate / catalyst ratio=100000) was added to the reactor, at 25 After stirring for 2 hours at °C, the reaction pressure was adjusted to 8 MPa by injecting hydrogen, and the temperature was raised to 30 °C for 24 hours. The yield and optical purity were listed in Table 1 by gas chromatography.

[0062] After distilling off the toluene and the product, 441.8g of geranial was added to the reaction kettle, the reaction pressure was adjusted to 8MPa by injecting hydrogen, and the temperature was raised to 90°C for 8 hours. The yield and optical purity were measured by gas chr...

Embodiment 5-8

[0067] Embodiment 5-8 (preparation R-citronellal)

[0068] Under nitrogen atmosphere, 0.015mmol transition metal compound (see "transition metal compound" in Table 2 below) and 0.015mmol chiral bidentate bisphosphine ligand (see "ligand" in Table 2 below) and 100-200 Add 600g of neral aldehyde to 6 g of mesh basic alumina (the molar ratio of neral / geranial double bond isomers=99:1; the molar ratio of substrate / catalyst (based on the transition metal in the catalyst)=263157) , transferred it to an autoclave replaced with nitrogen, stirred at 25°C for 2 hours, and then adjusted a certain pressure by injecting hydrogen (see "Pressure" in Table 2 below for details), and raised the temperature to a certain temperature (see Table 2 for details) 2 "temperature"), after the reaction, the yield of R-citronellal was measured by gas chromatography, and the turnover number of the entire reaction was calculated based on the molar amount of R-citronellal and the molar amount of the transiti...

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Abstract

The invention provides a method for preparing optically active citronellal, and a catalyst for the method. The method comprises: in the presence of a catalyst, asymmetrically hydrogenating citral represented by a formula (I) and/or geranial represented by a formula (II) to prepare optically active R-citronellal represented by a formula (III), wherein the catalyst comprises rhodium as a catalytically active transition metal, a chiral bidentate diphosphine ligand, and basic alumina. According to the present invention, the catalytic stability of an optically active transition metal catalyst for asymmetric hydrogenation of homogeneous catalysis can be significantly improved without introducing of carbon monoxide so as to achieve high turnover number.

Description

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Claims

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Application Information

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Owner WANHUA CHEM GRP CO LTD
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