Study On Catalytic Synthesis And Separation Of Glycine With Monoethanolamine

On the base of summarization of several processes to industrially synthesize glycine, the paper studies a new glycine preparation process: monoethanolamine is contacted with the aqueous solution of sodium hydroxide and oxygenated at the presence of Raney Copper catalyst to obtain sodium salt of glycine, which is neutralized with hydrochloric acid and separated with sodium chloride using electrodialysis and membrane separation technology to obtain pure glycine.In this research Raney Copper catalyst is developed with noble metals. The optimal reaction temperature is between 150癈 and 190癈, 0.7MPa - l.lMPa for pressure and 200-400 mu for catalyst size. Through a number of contrastive experiments, we compare the conversion rate of monoethanolamine, selectivity of sodium salt of glycine, repeated times of catalyst itself and reaction time under the action of different catalysts. The experiment result demonstrates that the developed Raney Copper catalyst can not only improve the activity of the catalyst and last the longevity, but also can increase the conversion of monoethanolamine and shorten the reaction time. The conversion of monoethanolamine can reach 95% on the average, the selectivity of sodium salt of glycine is 99 %.The reacted mixture is neutralized with hydrochloric acid to obtain the mixture of glycine and sodium chloride. In this paper the electrodialysis and membrane separation technology is introduced to separate sodium chloride from mixture to get pure glycine after being condensed. We research the effect of varied flux on limited electrical current, time, separating rate of sodium chloride and energy consuming. Satisfied results are obtained, the yield of glycine can reach 92%, with 98% purification, which provides the basic data for pilot-experiment and industry producing.