Studies On The Process And Catalyst For Preparing N-Ethylpiperazine

N-ethylpiperazine is a versatile intermediate and organic chemical material. Starting from piperazine and ethanol,the craft conditions and catalyst of preparing N-ethylpiperazine by gas-solid phase catalytic under low-pressure were investigated systematically in this paper.By adding other components such as Co,Zn,Cr,Mg,Fe separately into the Copper-based activated alumina catalyst,the Cu-Zn/γ-Al₂O₃ was selected and optimized for this reaction according to the conversion of piperazine and the selectivty to N-ethylpiperazine.Then,under the best catalyst conditions,the optimum craft conditions were designed through single-factor and orthogonal experiments.The results obtained:1. From starting materials of piperazine and ethanol, the synthesis of N-ethylpiperazine by gas-solid phase catalytic under low pressure is applicable.2. The Cu-Zn/γ-Al₂O₃ prepared by impregnate method to the reaction shows high activity and selectivity to target product.Its best preparation conditions:activated alumina with particles equivalent diameter of 1.82 mm;infused for 48 hours at 25°C in the mix solution of 1.0mol/L Cu(NO₃)₂ and 0.5mol/L Zn(NO₃)₂;dried for 3 hours at 110°C;baked for 5hours at 500°C; activatied for 3 hours at 300°C in the reactor of 0.6 Mpa hydrogen pressure.3.The optimum craft conditions:the concentration of PA 30%(Quality score);reaction temperature 260±5°C;the airspeed counted as piperazine is 17.2h^-1,0.6 Mpa hydrogen pressure in reactor.In these conditions,the conversition of piperazine reaches 96.9%,the selectivity to N-ethylpiperazine is 85.1%,and to N,N'-diethylpiperazine is 8.9%.