Method for catalyzing vitamin A isomerization with ruthenium catalyst

A ruthenium catalyst and isomerization technology, applied in the field of isomerization of vitamin A catalyzed by ruthenium catalysts, can solve the problems of photosensitizer residue, inability to convert cis-isomers, serious environmental pollution, etc., and achieve high isomerization efficiency, Improved recovery rate and low reaction cost

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

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Problems solved by technology

However, there are certain defects and deficiencies in these three methods: the iodine-catalyzed scheme can only promote the conversion of the 11-cis isomer to the all-trans isomer, and the reaction process produces a large amount of iodine-containing wastewater, which is harmful to the environment. Severe pollution (US3384633); photosensitizers are often used in the photocatalytic process as cocatalysts to convert isomers, this method can convert 9-cis isomers to all-trans isomers, but the reaction process uses The residual photosensitizer found in the product will affect the chromaticity and shelf life of VA crystals (US03838029); there are relatively more reports on the use of metal catalysts to catalyze the conversion of VA isomers, such as the use of Pd catalysts to promote the conversion of 11-cis isomers to all The conversion of trans isomers (US04051174), but the reaction process is accompanied by a large amount of generation of 9-cis isomers, and the utilization rate of raw materials is not high;

Method used

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  • Method for catalyzing vitamin A isomerization with ruthenium catalyst
  • Method for catalyzing vitamin A isomerization with ruthenium catalyst
  • Method for catalyzing vitamin A isomerization with ruthenium catalyst

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0043] Auxiliary preparation:

[0044] (1) Preparation of urea-hydrogen peroxide complex: add 0.708kg 30% hydrogen peroxide (3eq.), 0.0125kg salicylic acid (0.1g / g) and 0.125kg urea (1.0eq.) to a 2L reactor, and keep warm at 5°C reaction. After the reaction is complete, cool down to -5°C, heat and stir for 3 hours, and then centrifuge. The centrifuged solid is rinsed with 0.375L petroleum ether (3ml / g), and the filter cake is a urea-hydrogen peroxide complex with a yield of 80% and a purity of 98%.

[0045] (2) The reaction process of preparing product 2-methoxypyridine-N-oxide compound: add 0.36L ethyl acetate (3ml / g) in 2L reactor, 0.155kg phthalic anhydride (1.0eq.), 0.109 kg 2-methoxypyridine (1.0 eq.). After the feeding is complete, raise the temperature of the system to 100°C, add 0.20kg of urea-hydrogen peroxide complex (2.0eq) to the system, and keep it warm for reaction; Turn blue again, then adjust the pH of the system to 9 with 20% sodium hydroxide, centrifuge, e...

Embodiment 2

[0051] Auxiliary preparation:

[0052] (1) Preparation of urea-hydrogen peroxide complex: add 0.708kg 30% hydrogen peroxide (3eq.), 0.0125kg salicylic acid (0.1g / g) and 0.125kg urea (1.0eq.) to a 2L reactor, and keep warm at 5°C reaction. After the reaction is complete, cool down to -5°C, heat and stir for 3 hours, and then centrifuge. The centrifuged solid is rinsed with 0.375L petroleum ether (3ml / g), and the filter cake is a urea-hydrogen peroxide complex with a yield of 80% and a purity of 98%.

[0053] (2) The reaction process of preparing the product 2-chloropyridine-N-oxide: add 0.36L ethyl acetate (3ml / g), 0.155kg phthalic anhydride (1.0eq.), 0.12kg to a 2L reactor 2-Chloropyridine (1.0 eq.). After the feeding is complete, raise the temperature of the system to 100°C, add 0.20kg of urea-hydrogen peroxide complex (2.0eq) to the system, and keep it warm for reaction; It turned blue again, then adjusted the pH of the system to 9 with 20% sodium hydroxide, centrifuged, ...

Embodiment 3

[0059] Auxiliary preparation:

[0060] (1) Preparation of urea-hydrogen peroxide complex: add 0.708kg 30% hydrogen peroxide (3eq.), 0.0125kg salicylic acid (0.1g / g) and 0.125kg urea (1.0eq.) to a 2L reactor, and keep warm at 5°C reaction. After the reaction is complete, cool down to -5°C, heat and stir for 3 hours, and then centrifuge. The centrifuged solid is rinsed with 0.375L petroleum ether (3ml / g), and the filter cake is a urea-hydrogen peroxide complex with a yield of 80% and a purity of 98%.

[0061] (2) The reaction process of preparing product 4-picoline-N-oxide: add 0.36L ethyl acetate (3ml / g) in 2L reactor, 0.155kg phthalic anhydride (1.0eq.), 0.093 kg 4-picoline (1.0 eq.). After the feeding is complete, raise the temperature of the system to 100°C, add 0.20kg of urea-hydrogen peroxide complex (2.0eq) to the system, and keep it warm for reaction; Turn blue again, then adjust the pH of the system to 9 with 20% sodium hydroxide, centrifuge, extract, and combine and...

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PUM

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Abstract

The invention provides a method for catalyzing vitamin A isomer conversion with a ruthenium catalyst. According to the method, a ruthenium compound is used as a catalyst, various vitamin A cis-isomerswith low biological activity can be converted into all-trans-isomers with high biological activity in a high proportion in the presence of an auxiliary agent, and the cis-isomers comprise 9-cis-isomers, 11-cis-isomers and 13-cis-isomers. The method has the characteristics of cheap and easily available catalyst, less catalyst dosage, mild reaction conditions, low reaction cost, high isomerizationefficiency and the like.

Description

technical field [0001] The invention belongs to the field of synthesis of chemical intermediates, and in particular relates to a method for catalyzing vitamin A isomerization with a ruthenium catalyst. Background technique [0002] Vitamin A (VA) is one of the essential vitamins for humans and animals. It is the basic substance required for the growth and development of the body, reproduction and vision, and affects the regulation of cell proliferation and differentiation. In addition to being used clinically to treat night blindness, conjunctivomalacia and xerosis cornea, it is also used as a food nutrition fortifier and animal feed additive. The structural formula is as follows. [0003] [0004] VA has a polyene structure with four conjugated double bonds on the side chain, and theoretically there are 16 cis-trans isomers, but due to steric hindrance effects, the only geometric isomers that exist in nature are all-trans without steric hindrance. body, 9-cis body, 13-c...

Claims

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Application Information

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IPC IPC(8): C07C403/12
CPCC07C403/12C07B2200/09C07C2601/16
Inventor 翟文超鹿宝华张旭吕英东张涛
Owner WANHUA CHEM GRP CO LTD
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