Gas-solid Phase Catalytic Synthesis Of Anhydrous Piperazine And Kinetic Study

The paper has reviewed physical and chemical properties, production status and related uses of piperazine. Based on consulting the domestic and international reference documents and predecessor study, deamination of industrial ethylenediamine on normal pressure is determined by a comparison of processes available. Modified K-ZSM-5 zeolite catalysts are prepared with the method of ion-exchange. Then monofactor method and multifactor orthogonalizing design method are applied to get the optimum processing conditions in preparation of piperazine. After that the macrokinetics model on the gas-solid reaction is established based on related theories. To provided the theoretic basis and experimental base with industrialized production of piperazine.The following have been obtained through lots of experiments.1. The way of synthesis of piperazine using the industrial ethylenediamine as rawmaterial is applicable, the Higher activity and selectivity of K-ZSM-5 catalyst prepared by the method of ion-exchange was obtained. The optimal conditions for preparing catalysts: ZSM-5 zeolite catalysts with the ratio of silicon to aluminum 50;infused for 48 hours at 25 ℃ in 1 .0mol/L KCl;dried for 3 hours at 110℃;baked for 6 hours at 500℃ activated for 2.5 hours at 450℃.2. The optimal processing conditions: the concentration of EDA 50%(mass fraction);reaction temperature 350 ±5 ℃;space velocity 2.532 × 10^-3 mol·g^-1·hr^-1. In these conditions, the conversition of EDA is 97.28%, the yield of PA is 50.87%, the yield of TEDA is 34.82% and the total yield is 85.70%.3. The mechanism for synthesizing piperazine has been discussed ,and its macrokinetics model has been founded, the activation energy and reaction velocity constant of piperazine and TEDA has been obtained, the results provided theoretic basis for industrialized production.