Study On The Novel Process For Synthesis Of (2s)-3-methyl-2-(2,2,2-Trifluoethoxy Carbonyl Amino)-butyronitrile And The Pilot Plant Test

(2s)-3-methyl-2-(2,2,2-trifluoethoxycarbonylamino)-butyronitrile(TVNT)is one of the important intermediates in synthesis of tolprocarb,which is a kind of carbamate bactericide widely used in rice planting with a good control effect on the rice blast.And the rice blast has a rising trend in rice farming in present,hence it is becoming essential to develop this kind of bactericide.The target compound TVNT has the advantage of wide application and large market requirement.Based on the translation and reading of the bibliographer and analysis of the principle of synthesis,the novel process for synthesis TVNT was developed in the Dissertation.The mechanism of the main reaction and the process parameters were studied carefully.Finally,the process was developed which was used phosgene as the raw material.The TEC(trifluoroethoxy formyl chloride)was synthesized by trifluoroethanol and phosgene.Tributylamine was the acid acceptor and toluene was used as the solvent.Then the best experimental conditions(n(trifluoroethanol):n(phosgene)=1:1.2,150ml toluene and n(tributylamine):n(trifluoroethanol)=1:1,5℃)were gotten.The conversion was about 96%.The TVA was obtained by the TEC and L-valine with the existence of 30%NaOH solution.By analyzing the experimental results,it was believed that the optimal process parameters(n(TEC):n(L-valine)= 1.03:1,toluene as the solvent,5℃,pH=12±0.5 during reaction and pH=1.5±0.5 during acidolysis)were gotten with the yield 98%(based on TEC).The TVAC was first synthesized by the acyl chlorination reaction between the TVA and phosgene with DMF as the catalyst,and the optimal process parameters(n(TVA):n(phosgene)=1:1.6,40±2℃,n(DMF):n(TVA)=0.05:1)was obtained.The TVAD was obtained sequentially by TVAC and ammonia gas with DMF as solvent.The optimal process parameters(n(TVAC):n(ammonia)=1:2.12,below 10℃,adding TVAC as fast as possible)were then selected with the yield 87.7%(based on TVA).The target compound TVNT was obtained by the dehydrating reaction of TVAD with phosgene as dehydrating agent and the results showed that the yield of 90.0%.The optimal process parameters(n(TVAD):n(phosgene)=1:1.9,15±5 ℃)was studied.The yield of final TVNT product after distillation was 85.5%.The total yield of TVNT was 70.5%(based on L-valine).Based on the theoretical analysis and the experimental results,the ideal process parameters was optimized and selected.The synthetic route and related equipments was analyzed systematically and evaluated by the pilot plant test.The experimental results of the pilot plant were similar with the laboratory,which meant that large scale production of target compound was feasible with this route.