Study On Sepation And Preparation Technology Of The Glycine By Ion-Exchange Membrance

Glycine, also known as amino acid, is widely used in pesticides, medicine, food, feed and fertilizer industries, is also widely used in fine chemical products and organic synthesis intermediates. Aimed at the problems in the production of glycine, with a focus difficulty lies in the separation of glycine and ammonium chloride, this topic will address the difficult way to conduct a study using electrodialysis.In this research, glycine was synthesized by the chloroacetic acid ammonolysis process and separated and purified by electrodialysis technology. The effects of reaction temperature, reaction time, reactant ratio as well as PH value on the product yield were investigated. From the optimal and comprehensive consideration of the efficiency of industrial production, the optimum conditions for synthesis of glycine are as follows: the reaction temperature is 60℃, the reactant ratio is 2.0:1.0 and the reaction time is 3.0h.The electrodialysis technology was used in this research, in which the ion-exchange membrane was selected to separate ammonium chloride from a mixture of glycine and ammonium chloride by the potential difference as a driving force. First of all, through the screening and optimization of ion-exchange membrane composition and structure as well as the adjusting of the internal structure and group allocation of the traditional ion-exchange membrane separation unit, the optimum separation instrument and ion-exchange membrane were selected. Then, a systematic study on separation technology of glycine was carried out. The effects of the composition of the mixture, limiting current size and the membrane stack voltage on separation efficiency of the ion-exchange membrane were investigated. Moreover, the variation of the ion concentration of the thick room and the light room with the separation time was also investigated. Finally, we determine the optimum technology parameters for glycine membrane separation, that is, the operating voltage is 15v, light room glycine concentration is 240g / L, the flow rate of the light-room is 80 L / h, the flow rate of the thick-room is 80 L / h, the flow rate of the electrochemical room is 60 L / h. By which a high quality glycine product was obtained with a yield of 89.3%, in which the purity of glycine reaches to 99.80% and the content of chloride ion is less than 0.022%.