Study On The New Synthesis Process Of Ethyl Bromodifluoroacetate

Based on the summary of methyl chloroacetate、ethyl difluoroacetate、ethyl bromodifluoroacetate,the synthesis of ethyl dichloroacetate、ethyl difluoroacetate、 ethyl bromodifluoroacetate are studied,we got the suitable technological conditions via analysis of the influencing factors of reaction yield and their structure was confirmed via analysis of Refractive index、IR、1NMR、1C NMR、MS, finally,the solvent and raw materials was recycled and the reaction principle were analyzed.Ethyl dichloroacetate is synthesized with dichloroacetic acid as the material、 alcohol as the solvent and the material, FeCl3·6H2O as the catalyst and cyclohexane as water-carrying agent. The effects of the different water-carrying agent and dosage of the water-carrying agent、the dosage of the catalyst and alcohol、the catalytic properties of catalyst used on the yield of ethyl dichloroacetate were investigated.The optimized synthesis parameters are as follows:the consumption of dichloroacetic acid and FeCl3·6H2O is12.9g and0.5g respectively, the amount of cyclohexane and alcohol is15mL and20mL repectively, the water carrying time is40min. The yield is85.4%, the catalyst can be recycled when necessary.Ethyl difluoroacetate is synthesized with ethyl dichloroacetate synthesized in my laboratory as the material、potassium fluoride as the material and catalyst、 propanetriol as the sovent. The effects of the different times、the different sovent and amount of the sovent on the yield of ethyl difluoroacetate is investigated、the percent recovery of material and sovent is also statisticsed. The optimized synthesis parameters are as follows:the consumption of ethyl dichloroacetate and anhydrous potassium fluoride is30g and7.5g respectively, the amount of propanetriol is50mL, the reaction temperature is152℃and the reaction time is3.5h, the yield of the product is32.8%, the average percent recovery of material is63.1%, the product selectivity is high, the average percent recovery of sovent is94.2%and up to100%. Ethyl bromodifluoroacetate is synthesized with ethyl difluoroacetate synthesized in my laboratory as the material、cupric bromide as the brominating agent、phosphorus tribromide as the catalyst and DMF as the sovent. The effects of the activity of different catalysts and bromating agents、the different reaction temperature and the different time on the yield of ethyl bromodifluoroacetate is investigated. the percent recovery of material and sovent is also statisticsed. The optimized synthesis parameters are as follows:the consumption of ethyl difluoroacetate and cupric bromide is12.4g and11.2g respectively, the consumption of red phosphorus and Bromine is3g and22g respectively, the reaction temperature is60℃and the reaction time is65h, the yield is10.9%, the unreacted materials can be recycled and the percent recovery is84.7%.