Method for utilizing dilute sulphuric acid to catalyze and hydrolyze alpha,alpha'-dicyano-1,1-cyclohexanediacetamide to prepare 1,1-cyclohexanediacetic acid

A technology of cyclohexyldiacetimide and cyclohexyldiacetic acid, which is applied in the fields of nitrile preparation and organic chemistry, can solve the problems affecting industrial application, high reaction temperature, and long reaction time, and achieve green preparation, high reaction temperature, and fast response effect

Inactive Publication Date: 2010-06-02
ZHEJIANG UNIV
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

A method for preparing 1,1-cyclohexyldiacetic acid by non-catalytic hydrolysis of α,α'-dicyano-1,1-cyclohexyldiacetimide ammonium salt in near-critical water medium, invention patent, ZL200610155596.8), but Due to the weak self-catalysis ability of near-critical water, there is a method for preparing 1,1-cyclohexyldiacetic acid by non-catalytic hydrolysis of α,α'-dicyano-1,1-cyclohexyldiacetimide ammonium salt in near-critical water medium The disadvantages such as slow reaction speed, high reaction temperature, low reaction yield and long reaction time affect the industrial application of this technology

Method used

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  • Method for utilizing dilute sulphuric acid to catalyze and hydrolyze alpha,alpha'-dicyano-1,1-cyclohexanediacetamide to prepare 1,1-cyclohexanediacetic acid
  • Method for utilizing dilute sulphuric acid to catalyze and hydrolyze alpha,alpha'-dicyano-1,1-cyclohexanediacetamide to prepare 1,1-cyclohexanediacetic acid
  • Method for utilizing dilute sulphuric acid to catalyze and hydrolyze alpha,alpha'-dicyano-1,1-cyclohexanediacetamide to prepare 1,1-cyclohexanediacetic acid

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Embodiment 1

[0037] Add 360g of dilute sulfuric acid aqueous solution and 18g of α,α'-dicyano-1,1-cyclohexyl diacetylimide into a 500mL batch-type autoclave, wherein the mass concentration of sulfuric acid in the dilute sulfuric acid aqueous solution is 20%, and the dilute sulfuric acid aqueous solution The weight ratio of α, α'-dicyano-1, 1-cyclohexyldiacetimide is 20. Turn on stirring, heat up to boiling under normal pressure, open the exhaust valve for 2 minutes, and use water vapor to remove the air in the kettle; close the exhaust valve, continue to heat up to 250°C for 10 minutes for hydrolysis; the reaction solution is cooled and left to stand, then filtered to obtain a filter cake Dissolve the filter cake in an aqueous solution containing 20% ​​ethanol (volume concentration) at 50°C, and filter while it is hot; the filtrate crystallizes after cooling, and obtains the product 1,1-cyclohexyldiacetic acid 10.3g after filtering, washing with water, and vacuum drying, the product The pu...

Embodiment 2

[0039] Add 330g of dilute sulfuric acid aqueous solution and 22g of α,α'-dicyano-1,1-cyclohexyl diacetylimide in a 500mL batch-type autoclave, wherein the mass concentration of sulfuric acid in the dilute sulfuric acid aqueous solution is 15%, dilute sulfuric acid The weight ratio of aqueous solution to α,α'-dicyano-1,1-cyclohexyl diacetimide is 15. Turn on stirring, heat up to boiling under normal pressure, open the exhaust valve for 4 minutes, and use water vapor to remove the air in the kettle; close the exhaust valve, continue to heat up to 230°C for 25 minutes for hydrolysis; the reaction solution is cooled and left to stand, then filtered to obtain a filter cake Dissolve the filter cake in an aqueous solution containing 30% ethanol (volume concentration) at 55°C, and filter while it is hot; the filtrate crystallizes after cooling, and obtains the product 1,1-cyclohexyldiacetic acid 15.1g after filtering, washing with water, and vacuum drying, the product The purity by HP...

Embodiment 3

[0041]Add 300g of dilute sulfuric acid aqueous solution and 30g of α,α'-dicyano-1,1-cyclohexyl diacetylimide in a 500mL batch-type autoclave, wherein the mass concentration of sulfuric acid in the dilute sulfuric acid aqueous solution is 10%, dilute sulfuric acid The weight ratio of aqueous solution to α,α'-dicyano-1,1-cyclohexyl diacetimide is 10. Turn on stirring, heat up to boiling under normal pressure, open the exhaust valve for 5 minutes, and use water vapor to remove the air in the kettle; close the exhaust valve, continue to heat up to 210°C for 45 minutes for hydrolysis; the reaction solution is cooled and left to stand, then filtered to obtain a filter cake Dissolve the filter cake in an aqueous solution containing 40% ethanol (volume concentration) at 60°C, and filter while it is hot; the filtrate crystallizes after cooling, and obtains the product 1,1-cyclohexyldiacetic acid 22.6g after filtering, washing with water, and vacuum drying. The purity by HPLC analysis w...

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Abstract

The invention discloses a method for utilizing dilute sulphuric acid to catalyze and hydrolyze alpha,alpha'-dicyano-1,1-cyclohexanediacetamide to prepare 1,1-cyclohexanediacetic acid, comprising the steps of 1) adding dilute sulphuric acid aqueous solution with the mass concentration being between 2% and 20% and alpha,alpha'-dicyano-1,1-cyclohexanediacetamide into a high-pressure reactor, wherein the weight ratio between dilute sulphuric acid aqueous solution and alpha,alpha'-dicyano-1,1-cyclohexanediacetamide is 4:1 to 20:1; stirring and heating up to boiling under atmospheric pressure, then exhausting for 2 to 5 minutes; 2) heating up the reacting solution to 150-250 DEG C, then hydrolyzing for 10 to 120 minutes; 3) filtering to obtain filter cake after the cooling and standing of the reacting solution; 4) dissolving the filter cake hot ethanol aqueous solution and filtering while hot; and 5) crystallizing after cooling of the filtrate, filtering, washing and vacuum drying to obtain the product 1,1-cyclohexanediacetic acid. The method utilizes dilute sulphuric acid to hydrolyze in the hydrolytic process, thus reducing environment pollution, and greatly reducing the dosage of sulphuric acid and corrosion degree to apparatus; and the invention is characterized by simple reacting process, high products yield and purity, and highly improved greening degree in the production process.

Description

technical field [0001] The invention relates to a method for preparing 1,1-cyclohexyldiacetic acid by dilute sulfuric acid catalytic hydrolysis of α,α'-dicyano-1,1-cyclohexyldiacetimide. Background technique [0002] The chemical name of Gabapentin (Gabapentin, CAS NO: 60142-96-3) is 1-(aminomethyl)-cyclohexylacetic acid, which is a derivative of γ-aminobutyric acid (GABA), and its structural formula is: [0003] [0004] Gabapentin is an antiepileptic drug with different pharmacological effects from other existing antiepileptic drugs. Studies have shown that gabapentin acts by changing the metabolism of GABA. Gabapentin has been shown to prevent epilepsy in various animal models. In addition, it has also shown effects in animal models of spasticity, analgesia and amyotrophic lateral sclerosis. Gabapentin has a high affinity for novel binding sites in brain tissue, and it can pass through some barriers in the body through amino acid transfer bodies. Compared with other a...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C55/02C07C51/08
Inventor 吕秀阳任浩明
Owner ZHEJIANG UNIV
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