Study On The Catalytic Synthesis Of Cis-Propenylphosphonic Acid By 1,2-Propadienyl-Phosphonic Acid In Aqueous Medium

The catalytic hydrogenation of 1,2-propadienyl-phosphonic acid to cis-propenylphosphonic acid is necessary affecting the industrial production of fosfomycin.Catalytic synthesis of cis-propenylphosphonic acid by1,2-propadienyl-phosphonic acid in aqueous media can greatly improve production safety and reduce production costs.Therefore,it is of great practical significance to explore the optimal process conditions of the synthesis process and the kinetic model of the reaction.In this study,the effect of stirring speed,reaction temperature,hydrogen pressure,reaction time and catalyst dosage on the selectivity and yield of cis-propenylphosphonic acid was determined by using single-factor experiment using water as solvent and 5%Pd/C catalyst.The optimum process conditions are:stirring speed is 1200 r/min,5%Pd/C catalyst dosage is 0.375 g,reaction temperature is 45?,hydrogen pressure is 0.3 MPa,reaction time is 10 h.Under this reaction condition,The conversion of1,2-propadienyl-phosphonic acid reached 100%and the selectivity to cis-propenylphosphonic acid reached 71.38%.With water as solvent,using 5%Pd/C catalyst,on the basis of1,2-propadienyl-phosphonic acid catalytic hydrogenation of appropriate process parameters,both inside and outside the elimination of diffusion and mass transfer process conditions,the reaction temperature were studied in 45?,35?and 40?,50?and55?,the hydrogen pressure was at 0.1 MPa,0.15 MPa,0.20 MPa,0.25 MPa,0.30 MPa,and 0.35 MPa,Intrinsic kinetic equation for hydrogenation of 1,2-propadienyl-phosphonic acid was researched.The appropriate dynamic model was selected and tested with experimental data.The kinetic parameters of catalytic hydrogenation of1,2-propadienyl-phosphonic acid were obtained by fitting.According to the kinetic parameters,the intrinsic kinetic equation of catalytic hydrogenation of1,2-propadienyl-phosphonic acid was established:???In this thesis,a core-shell type noble metal nanocatalyst Fe₃O₄/Pd@NC which can be used for aqueous phase reaction was prepared by hydrothermal method.The effects of stirring rate,reaction temperature,hydrogen pressure,reaction time and catalyst dosage on the hydrogenation reaction of Fe₃O₄/Pd@NC catalyst in the catalytic hydrogenation of1,2-propadienyl-phosphonic acid in aqueous medium were investigated by single factor experiments.The optimum process conditions were determined:the stirring speed was1200 r/min,the catalyst dosage was 0.425 g,the reaction temperature was 45?,the hydrogen pressure was 0.3 MPa,and the reaction time was 9 h.Under this reaction condition,the 1,2-propadienyl-phosphonic acid was determined.The conversion rate reached 100%and the cis-propenylphosphonic acid selectivity reached 74.23%.The catalytic performance of Fe₃O₄/Pd@NC catalyst was studied from the aspects of dispersibility,catalytic effect,stability and catalyst recovery by using hydrogen peroxide reaction as the target reaction.The results show that the Fe₃O₄/Pd@NC catalyst has good catalytic activity and stability,and is easy to recycle,and can be quickly recovered by magnetic separation operation.