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Method for electrochemical synthesis of N-acetyl-L-cysteine from L-cystine

A cysteine ​​and cystine technology, applied in the field of organic electrochemical synthesis, can solve the problems of easy racemization of L-type amino acids, high L-cysteine ​​content, increased cost and investment, etc., and achieve easy production and operation. , The effect of simple process and low production cost

Inactive Publication Date: 2019-10-18
JILIN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0006] In this process, the salt content is too high, separation is difficult, and in the process of acetylation, L-cysteine ​​salt is easily oxidized to L-cystine salt, which requires inert gas protection, and L-amino acid is prone to racemization
And in the production wastewater, the content of L-cysteine ​​is high, the waste of raw materials is serious, and the cost input is increased

Method used

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  • Method for electrochemical synthesis of N-acetyl-L-cysteine from L-cystine
  • Method for electrochemical synthesis of N-acetyl-L-cysteine from L-cystine

Examples

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example 1

[0031] (1) Acetylation of L-cystine to prepare N,N'-diacetyl-L-cystine

[0032] Take 24g L-cystine and dissolve it in 250mL of 1mol L -1 In the sodium hydroxide solution, stir vigorously in an ice water (0°C) bath, then add 40mL of acetic anhydride dropwise, during the process of adding acetic anhydride, continuously add 1mol L -1 Sodium hydroxide, to keep the pH of the reaction solution at about 10, continue stirring for 30min after the addition of acetic anhydride, and then add 1.5mol L -1 hydrochloric acid to adjust the pH to 2. Put the reaction solution in an electrodialyzer to remove salt, when the conductivity of the dilute chamber reaches 500μS cm -1 The electrodialysis was stopped at the following time. Heat the desalinated solution to 60°C, stir and add activated carbon for decolorization, keep warm for 30 minutes for decolorization, and obtain a clear solution after filtration. The solution after electrodialysis was distilled under reduced pressure until all the ...

example 2

[0036] (1) Acetylation of L-cystine to prepare N,N'-diacetyl-L-cystine

[0037] Dissolve 24g of L-cystine into 125mL of 2mol L -1 In the sodium hydroxide solution, stir vigorously in an ice water (0°C) bath, then add 40mL of acetic anhydride dropwise, and continuously add 2mol L of acetic anhydride during the dropwise addition of acetic anhydride-1 Sodium hydroxide, to keep the pH of the reaction solution at about 10, continue stirring for 30min after the addition of the acid anhydride, and then add 3mol L -1 hydrochloric acid to adjust the pH to 2. Put the reaction solution in an electrodialyzer to remove salt, when the conductivity of the dilute chamber reaches 500μS cm -1 The electrodialysis is stopped at the following time. Heat the desalinated solution to 60°C, stir and add activated carbon for decolorization, keep warm for 30 minutes for decolorization, and obtain a clear solution after filtration. The electrodialysis solution was distilled under reduced pressure unti...

example 3

[0041] (1) Acetylation of L-cystine to prepare N,N'-diacetyl-L-cystine

[0042] Take 1200g L-cystine and dissolve it into 6.25L of 2mol L -1 Sodium hydroxide solution, then placed in a double-layer reactor, vigorously stirred in a circulating ice water (0°C) bath, then slowly added 1.5L of acetic anhydride, in the process of dropping acetic anhydride, continuously added 2mol L -1 Sodium hydroxide, to keep the pH of the reaction solution at about 10, continue stirring for 30min after the addition of the acid anhydride, and then add 3mol L -1 hydrochloric acid to adjust the pH to 2. Put the reaction solution in an electrodialyzer to remove salt, when the conductivity of the dilute chamber reaches 500μS cm -1 The electrodialysis is stopped at the following time. Heat the desalinated solution to 60°C, stir and add activated carbon for decolorization, keep warm for 30 minutes for decolorization, and obtain a clear solution after filtration. The electrodialysis solution was dist...

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Abstract

The invention discloses a process method for electrochemical synthesis of N-acetyl-L-cysteine from L-cystine. The method mainly needs the following raw materials: L-cystine, acetic anhydride, liquid alkali, hydrochloric acid, sulfuric acid, deionized water, etc. The method includes: firstly, subjecting L-cystine to acetylation reaction, then conducting electrodialysis desalination, reduced pressure distillation concentration and cooling crystallization to obtain an N, N-diacetyl-L-cystine crystal, then dissolving N, N-diacetyl-L-cystine crystal in a sulfuric acid solution to prepare a cathodesolution, taking a sulfuric acid solution as an anode solution, using lead or carbon as the cathode, taking a ruthenium titanium tin electrode as the anode, conducting electrolytic reduction, and thencarrying out evaporation concentration, cooling crystallization, recrystallization and the like to obtain N-acetyl-L-cysteine. Compared with the traditional method, the method provided by the invention has the advantages of few steps, simple process, high product purity and quality, and low cost, at the same time avoids the problems of easy oxidation and racemization of the product, also the electrochemical process is green and pollution-free, and the social value and economic value are obvious.

Description

Technical field: [0001] The invention relates to the field of organic electrochemical synthesis, in particular to the synthesis of N-acetyl-L-cysteine ​​from L-cystine through an electrochemical reduction method, which has important applications in the fields of medicine, cosmetics and biochemistry. Background technique: [0002] N-acetyl-L-cysteine ​​(NAC), chemical formula C 5 h 9 NO 3 S, molecular weight 163.19, white crystal powder, has a garlic-like smell. Strong hygroscopicity, soluble in water and ethanol, insoluble in ether and chloroform. [0003] It is an acetylated derivative of cysteine, and the molecule contains a sulfhydryl group, which can break the disulfide bond in the peptide bond of mucin, thereby decomposing the protein into small molecular peptides, thereby thinning the mucus, and can be used as an expectorant . The sulfhydryl group of NAC can interact with the oxidizing group, avoiding the inactivation of certain elastase inhibitors and strong oxid...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C25B3/04C25B3/25
CPCC25B3/25
Inventor 林海波丛林川
Owner JILIN UNIV
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