Study On Synthesis And Exploration Of Glyphosate By Alkyl Ester Method

In this paper,the process conditions for the synthesis of glyphosate by alkyl ester method were investigated.The key factors affecting the yield of glyphosate were studied.By qualitative and quantitative analysis,the variation law of product yield under different process conditions was summarized,and several factors affecting the reaction selectivity were clarified: material ratio,reaction temperature,reaction time,PH,etc.If the optimal ratio is paraformaldehyde: triethylamine: anhydrous methanol:dimethyl phosphite: hydrochloric acid: glycine =2:0.75-0.8:6-7:1.25:3-3.The optimum process time is: esterification reaction of dimethyl phosphite with glycine formaldehyde conjugate 2h;addition reaction of glycine 1h;dehydrating agent 5A the amount of molecular sieve is 20% of the total mass of the reactant system,the number of times of reuse must not exceed 5 times,the temperature of solvent removal at atmospheric pressure is 70?,the optimum time of dissolution at atmospheric pressure is 4h,the optimum temperature condition of deacidification treatment by vacuum distillation is125?;the recrystallization solution is selected.water,the recrystallization solution is pH to 2 with alkali,the recrystallization time is 10 h under the condition of 0?,the number of times of recirculation application of recrystallization mother liquor is not more than 5 times;the optimum temperature for drying the recrystallization product is100-120?.Glyphosate yield up to 85% and purity up to 95%.The results of this thesis are of great practical and theoretical significance for the optimization control of glyphosate synthesis process and post-treatment process.