Study On Synthesis And Distillation Of Methyldiethoxyphosphine

In this study,methyl dichlorophosphine produced by a company in Jilin City was used as a raw material to synthesize methyldiethoxyphosphine,an important intermediate for glufosinate.The aim is to find a synthetic route with methyl dichlorophosphine as raw material,easy reaction,high yield and simple process.1.By analyzing the synthesis method of methyldiethoxyphosphine and combining with the development needs of local economy and chemical industry,methyl dichlorophosphine and ethanol were selected as the raw materials.To determine the experimental scheme for synthesis of diethyl methylphosphonate by ethoxy nucleophilic substitution.2.In the process of studying the synthetic route of methyl phosphine dichloride and ethanol,the experimental methods of single factor design and orthogonal design were adopted.Getting the best combination of factors:Using hexane as solvent,the dosage of hexane is V?CH3PCl2?:V?C6H14?=1:1.9,sodium hydride as acid-binding agent,the dosage of acid-binding agent is n?CH3PCl2?:n?NaH?=1:2.5,n?CH₃PCl₂?:n?C₂H₅OH?=1:2.7,the reaction temperature is 0 degrees,the titration rate is controlled at 2.5-3ml/min,stir at low temperature for 30 minutes and at room temperature for 90 minutes.The crude product of methyldiethoxyphosphine with purity of 85.4%was obtained by simple distillation,and the yield was 73.46%.3.Decompressive distillation of crude products and finding the optimum operating conditions.Pall ring was used as packing,vacuum was 7 Kpa,reflux ratio was 4:1,packing heigh was 75 cm,tbottom temperature was 100?,top temperature was 55?.After vacuum distillation,the purity of the product was 95.02%.4.During the experiment,the product was quantitatively analyzed by gas chromatography,and the content parameters of diethyl methylphosphonate in the solution were grasped in time.The structure of the product after distillation was characterized by LC-MS,IR,¹HNMR and ¹³CNMR,and the spectra were analyzed.