Research On Synthesis Process Of Glufosinate

This thesis is divided into two parts.The synthesis and optimization of the key intermediates of the herbicide glufosinate and the dissolution performance of quizalofop-p-ethyl are studied.Part one:Glufosinate is an organophosphorus herbicide.With the increasing demand of the global herbicide market,it has played an irreplaceable role in agricultural production due to its significant advantages such as high efficiency,low toxicity,and broad spectrum of herbicides control.However,glufosinate has many synthetic routes,and most processes have many problems,such as high cost,high safety risk,and complicated synthesis steps.This article uses 4-(hydroxymethylphosphono)-2-oxobutanoic acid(keto acid)synthesis method.Keto acids,the key intermediates of glufosinate,were prepared by using methyl phosphorus dichloride and acrylic acid as raw materials,followed by addition,esterification,Claisen condensation,and hydrolysis,and the process conditions of each step were optimized.Under the optimal process conditions,the purity of the keto acid product is 95.8%and the total yield of the four-step reaction is 54.8%.A single crystal of ketoacid was prepared by solvent evaporation method,and the crystal structure was characterized and analyzed.It was found that the keto acid had keto-enol tautomerism.In DMSO,the keto was the main type,and the crystals were all enolactone derivatives.Part two:quizalofop-p-ethyl as herbicide of aryloxyphenoxypropionate,which can effectively inhibit the growth of gramineous weeds in broad-leaved crops such as wheat and corn,and dicotyledonous crops,and the synthetic process has been reported to have a poor purification effect.To this end,a detailed study of its dissolution performance was performed.The solid-liquid equilibrium for quizalofop-p-ethyl in 12 solvents(methanol,ethanol,1-propanol,2-propanol,1-butanol,N,N-dimethylformamide(DMF),acetone,acetonitrile,ethyl acetate,1,4-dioxane,toluene,and 1-hexane)was measured by using a static equilibrium method at temperatures T=273.15-313.15 K under a pressure of 101.2 kPa.The results show that the solubility in those 12 monosolvents increases with increasing temperature.At a given temperature range,they gradually decrease in the following order:1,4-dioxane>acetonitrile>DMF>toluene>acetone>ethyl acetate>1-butanol>1-propanol>1-hexane>2-propanol>ethanol>methanol.A modified Apelblat model,λh model,Wilson model,and NRTL model were used to correlate the experiment values.Among them,the average relative deviation(RAD)value ranges from 0.07%to 2.29%,and the root mean square deviation(RMSD)value ranges from 0.04 × 10-4 to 4.57 × 10-4.The results show that these four thermodynamic models can be used to correlate the solubility of quizalofop-p-ethyl in measured solvents,and the Modified Apelblat model is more suitable.Furthermore,the thermodynamic properties of quizalofop-p-ethyl in monosolvents were calculated.At the same time,the thermodynamic properties of quizalofop-p-ethyl in pure solvents were calculated.The results show that its dissolution is spontaneous,providing a reference for the purification and separation of quizalofop-p-ethyl.