Electrosynthesis Of DL-Homocysteine Thiolactone Hydrochloride

With the development of society,the problems of high consumption,low output,and high emissions in the traditional chemical manufacturing industry have irreversibly damaged the living environment of human beings,which has caused unprecedented challenges to the economy and natural environment of various countries.The concept of green chemistry become a new direction for the development of the chemical industry.Organic electrochemistry uses electrons as reagents to obtain target products with high selectivity under normal temperature,normal pressure and low voltage,which is an important development direction of green chemistry.Electrochemical synthesis technology has great application potential in energy saving and emission reduction of high value-added fine chemicals production process.This article takes the electrochemical synthesis process of DL-homocysteine thiolactone hydrochloride as the research object.Through the optimization of electrolysis-related materials,equipment and process conditions,lay the foundation for industrial application,provide a demonstration for the application of electrochemical synthesis technology in the field of fine chemicals.The main research contents and results are as follows:DL-homocystine was used as raw material,hydrochloric acid solution was used as solvent,and modified graphite electrode was used as cathode and anode in plate-frame electrolysis cell to study DL-homocysteine.The effects of five process factors such as cathode current density,electrolysis temperature,DL-homocystine concentration,electrolyte flow rate and catholyte hydrochloric acid concentration on the electrolysis process were investigated,the results show that as the cathode current density and electrolyte flow rate increase,current efficiency increases first and then decreases.The current efficiency increases as the concentration of DL-homocystine in the electrolyte increases,but it decreased with the increase of the ratio of DL-homocystine to hydrochloric acid.In addition,it was found that within the studied temperature range,the DL-homocystine electrolysis efficiency was basically independent of temperature.Based on the above research results,the optimal reaction conditions were obtained:the concentration of DL-homocystine was 1.5 mol/L,the ratio of hydrochloric acid to DL-homocystine substance was 1:3,and the current density was 20 m A/cm~2,the flow rate is 60 m L/min.After the electrolysis process,the target product can be obtained through the steps of evaporation concentration,low temperature crystallization,filtration,purification and purification,and vacuum drying.In order to optimize the electrolysis process,the corresponding analytical test method was established based on high performance liquid chromatography to detect and quantitatively analyze the raw materials,intermediate products and target products,as follows:the volume ratio of phosphate buffer solution to acetonitrile in the mobile phase was 85:15,the UV detector wavelength was 220 nm,the column temperature was 28°C,the mobile phase flow rate was 1 m L/min,and the injection volume was 20μL.At the same time,the target product was characterized by nuclear magnetic and infrared to further verify the structure of the target product.Based on the above research,the thesis carried out the scale-up experiment of DL-homocysteine thiolactone hydrochloride,and an electrochemical reactor with an annual output of 1000 t DL-homocysteine thiolactone hydrochloride was designed based on the scaled-up test results.Further material balance and economic analysis were carried out on the industrial production project with an annual output of 1000 t DL-homocysteine thiolactone hydrochloride,lay the foundation for industrial application.