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6,8-dichloro ethyl caprylate preparation method

A technology for ethyl dichlorooctanoate and ethyl chlorooctanoate is applied in the field of preparation of ethyl 6,8-dichlorooctanoate, and can solve the problems of intractable industrial waste water, strong corrosiveness, inability to be recovered by distillation and other methods, and the like, It is suitable for large-scale industrial production, the reaction conditions are mild and easy to control, and the product yield and product purity are high.

Inactive Publication Date: 2017-07-21
JIANGSU TOHOPE PHARMA
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, after the final alkalization and neutralization, the washing layer contains pyridine, DMF, triethylamine and other components, which is highly corrosive and miscible with water to form an azeotrope. In actual production, it cannot be recovered by distillation, etc., and can only rely on a large amount of dilution. After doing harmless treatment, it is a kind of difficult-to-treat industrial wastewater

Method used

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  • 6,8-dichloro ethyl caprylate preparation method

Examples

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Comparison scheme
Effect test

Embodiment 1

[0020] Under ice-water bath conditions, put 297Kg thionyl chloride and 1485Kg toluene into a 3000L reactor, slowly add 540Kg 6-hydroxy-8-chlorooctanoic acid ethyl ester dropwise, and at the same time pass dry air into it to continue bubbling, and control the air flow rate to 6.48 L / min (that is, the air flow rate is controlled at 0.012L / min per kilogram of 6-hydroxy-8-chlorooctanoic acid ethyl ester), after 2 hours, the temperature is raised to 30-35°C, kept for 1 hour, and then heated to about 90 ~100°C, stop bubbling, keep warm for 2 hours, the reaction solution is neutralized to neutral with 20% sodium carbonate aqueous solution, separate layers, the organic layer is evaporated to remove the solvent under normal pressure, and the 170~180 ℃ distillate to obtain 480Kg 6,8-dichlorooctanoic acid ethyl ester with a purity of 98.3%.

Embodiment 2

[0022] Under ice-water bath conditions, put 324Kg thionyl chloride and 1300Kg toluene into a 3000L reactor, slowly add 540Kg 6-hydroxy-8-chlorooctanoic acid ethyl ester dropwise, and simultaneously feed dry nitrogen to continue bubbling, and control the nitrogen flow rate to 8.1 L / min (that is, the nitrogen flow rate of 6-hydroxy-8-chlorooctanoic acid ethyl ester is controlled at 0.015L / min), after 2 hours, the temperature is raised to 30-35°C, kept for 1 hour, and then heated to about 90 ~100°C, stop bubbling, keep warm for 2 hours, the reaction solution is neutralized to neutral with 20% sodium carbonate aqueous solution, separate layers, the organic layer is evaporated to remove the solvent under normal pressure, and the 170~180 ℃ distillate to obtain 490Kg 6,8-dichlorooctanoic acid ethyl ester with a purity of 98.5%.

Embodiment 3

[0024] Under ice-water bath condition, drop 350Kg thionyl chloride and 1050Kg toluene into 3000L reaction kettle, slowly add dropwise 540Kg6-hydroxyl-8-chlorooctanoic acid ethyl ester, pass into dry air at the same time and continue bubbling, drop in 2 hours, and Control the air flow rate to 8.1L / min (that is, control the air flow rate at 0.015L / min per kilogram of 6-hydroxy-8-chlorooctanoic acid ethyl ester), then raise the temperature to 30-35°C, keep it warm for 1 hour, and then raise the temperature to about 90 ~100°C, stop bubbling, keep warm for 2 hours, the reaction solution is neutralized to neutral with 20% sodium carbonate aqueous solution, separate layers, the organic layer is evaporated to remove the solvent under normal pressure, and the 170~180 ℃ distillate to obtain 485Kg of 6,8-dichlorooctanoic acid ethyl ester with a purity of 98.6%.

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Abstract

The present invention discloses a preparation method of a lipoic acid key intermediate 6,8-dichloro ethyl caprylate having a structure formula represented by a formula (I), wherein a nucleophilic substitution reaction is performed by using 6-hydroxy-8-chloro ethyl caprylate having a structure represented by a formula (II) as a raw material to substitute the hydroxyl with a chlorine atom so as to prepare the 6,8-dichloro ethyl caprylate. Compared to the preparation method in the prior art, the preparation method of the present invention mainly has the following advantages that the synthesis steps are simple, the use of the catalysts such as pyridine, DMF and triethylamine is avoided from the source, the generation of the difficultly-treated industrial sewage containing the catalysts is avoided, the reaction conditions are mild and are easy to control, the reaction is complete, the yield and the product purity are high, and the method is suitable for the large-scale industrial production. The formulas (I) and (II) are defined in the specification.

Description

technical field [0001] The invention belongs to the technical field of organic synthesis route design and preparation of raw materials and intermediates, and in particular relates to a preparation method of ethyl 6,8-dichlorooctanoate. Background technique [0002] [0003] 6,8-Dichlorooctanoic acid ethyl ester is a key intermediate for the preparation of lipoic acid starting from adipic acid, in which 6-hydroxy-8-chlorooctanoic acid ethyl ester is used to prepare 6,8-dichlorooctanoic acid ethyl ester. Lipoic acid has a strong antioxidant capacity, and is mainly used in the treatment of diabetic peripheral neuropathy in China; in addition to being used as a medicine, it is also widely used as a dietary supplement and cosmetic raw material abroad. [0004] There are many processes for preparing ethyl 6,8-dichlorooctanoate by chlorination of ethyl 6-hydroxy-8-chlorooctanoate. [0005] As in the literature [Zhuran1 Obshchei Khimii, 1964, 34, 3662], it is reported that 6-hy...

Claims

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Application Information

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IPC IPC(8): C07C67/307C07C69/63
Inventor 钱振青邹振荣陆惠刚殷屹峰龚利锋
Owner JIANGSU TOHOPE PHARMA
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