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Synthetic method for o-cyclodione

A synthesis method and technology of cyclic diketones, which are applied in the fields of preparation of carbonyl compounds by hydrolysis, preparation of oximes, organic chemistry, etc., can solve the problems of cyclohexanedione without a large market supply, difficult to realize industrialization, high price, etc., and reach the production cost Low, little environmental pollution, simple operation

Inactive Publication Date: 2014-08-06
APPLE FLAVOR & FRAGRANCE GRP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The known synthesis method of 5,6,7,8-tetrahydroquinoxaline is generally oxidation after condensation of cyclohexanedione and ethylenediamine, but cyclohexanedione is not available in large quantities in the market
Although the method has fewer steps, the yield is not high, and the reagent selenium dioxide used in the method is highly poisonous, difficult to operate and very expensive, and difficult to realize industrialization

Method used

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  • Synthetic method for o-cyclodione
  • Synthetic method for o-cyclodione
  • Synthetic method for o-cyclodione

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0022] (1) Add 100g of cyclohexanone and 5g of concentrated hydrochloric acid into a 500mL reaction flask, start stirring to make it evenly stirred, and slowly heat to 45°C. Add 130 g of isoamyl nitrite dropwise to the reaction flask within 1 hour, exothermic during the dropping process, and control the reaction within 50°C. After the dropwise addition was completed, the reaction was continued for 3 hours. After the reaction is complete, add soda ash to neutralize until the pH value is ≥ 7, and then carry out vacuum distillation. The vacuum degree is controlled at 75cmHg, the temperature is controlled below 50°C, and the distillation is carried out until no distillate is distilled. 1,2-cyclohexanedione mono 105 g of oxime crystals were precipitated, with a content of more than 98%, and a reaction yield of 81%.

[0023] (2) Add the 1,2-cyclohexanedione monoxime and 500ml of water prepared in the above step (1) into a 2000ml reaction bottle, add 70g of sodium nitrite, heat up t...

Embodiment 2

[0025] (1) Add 84g of cyclopentanone and 10g of concentrated hydrochloric acid into a 500mL reaction flask, start stirring to stir evenly, and slowly heat to 40°C. 103g of butyl nitrite was added dropwise to the reaction flask within 0.5 hours, exothermic during the dropwise addition, and the reaction was controlled within 45°C. After the dropwise addition was completed, the reaction was continued for 2 hours. After the reaction is complete, add soda ash to neutralize until the pH value is ≥ 7, and then carry out vacuum distillation. The vacuum degree is controlled at 75cmHg and the temperature is controlled below 50°C. 85g of oxime crystals were precipitated, with a content of more than 98%, and a reaction yield of 75%.

[0026] (2) Add 1,2-cyclopentanedione monoxime and 500ml of water prepared in the above step (1) into a 2000ml reaction bottle, add 75g of sodium nitrite, heat up to 40°C, and drop 800g of 50% Dilute sulfuric acid, add dropwise in about 2 hours, continue to...

Embodiment 3

[0028] (1) Add 100g of 2-methylcyclopentanone and 6g of concentrated hydrochloric acid into a 500mL reaction bottle, start stirring to make it evenly stirred, and drop 100g of isopropyl nitrite into the reaction bottle within 1 hour at room temperature. Exothermic, control the reaction within 25 °C. After the dropwise addition was completed, the reaction was continued for 2 hours. After the reaction is complete, add soda ash to neutralize until the pH value is ≥ 7, and then carry out vacuum distillation. The vacuum degree is controlled at 75cmHg, the temperature is controlled below 50°C, and steamed until no distillate is distilled. 3-Methyl-1,2- 98g of cyclopentanedione monoxime crystals were precipitated, with a content of more than 98%, and a reaction yield of 78%.

[0029] (2) Add 3-methyl-1,2-cyclopentanedione monoxime and 500ml of water prepared in the above step (1) into a 2000ml reaction bottle, add 80g of sodium nitrite, and heat up to 70°C , add 600g of 50% dilute ...

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Abstract

The invention discloses a synthetic method for o-cyclodione. O-cyclodione normally comprises 1,2-cyclopentanedione, 3-methyl-1,2-cyclopentanedione (methyl cyclopentenolone), 1,2-cyclohexanedione, 1,2-cyclononanedione, etc. 3-methyl-1,2-cyclopentanedione is an important perfume, and 1,2-cyclohexanedione is an important raw material for production of the perfume 5,6,7,8-tetrahydroquinoxaline. According to the invention, cyclic ketone is used as a starting raw material and subjected to nitrosation with nitrite, and an obtained intermediate cyclic ketoxime is subjected to hydrolysis so as to obtain o-cyclodione. The synthetic method provided by the invention has the advantages of simple technological operation, little pollution to the environment, high reaction yield and low production cost and is a promising production process.

Description

technical field [0001] The invention belongs to the field of fine chemicals, in particular to the production method of spices and spice intermediates, and relates to a synthesis method of orthocyclic diketones. Background technique [0002] Orthocyclic diketones, including 1,2-cyclopentanedione, 3-methyl-1,2-cyclopentanedione (methylcyclopentenolone), 1,2-cyclohexanedione, 1, 2-Cyclononanedione, etc., are important fine chemical intermediates, widely used in pharmaceuticals, flavors and fragrances and other industries. Among them, 3-methyl-1,2-cyclopentadione, also known as methylcyclopentenolone, is an important food spice with a prominent maple-like sweet aroma, so it is called maple lactone. It is said that it has a wide range of uses because of its caramel-like sweet aroma and nutty aroma. It can be used in various flavors such as coffee, cocoa, chocolate, and nuts. It is also widely used in tobacco flavors, detergents and In cosmetics, it can also be directly applied ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C45/42C07C49/403C07C49/395C07C49/413
CPCC07C45/42C07C249/06C07C49/403C07C49/395C07C49/413C07C251/44
Inventor 孟宪乐赵健张炯王冠石铭亮冯黎
Owner APPLE FLAVOR & FRAGRANCE GRP
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