固定床一步法连续合成N-甲基四氢吡咯与工艺改进

Progress of Producing N-methylpyrrolidine in Fixed-Bed Reactor by One-step Synthesis

四氢呋喃(THF)与一甲胺(MA)经自制负载γ-Al2O3床层的固定床反应器,催化脱水一步法合成N-甲基四氢吡咯,200吨/年生产装置工艺优化参数为:床层温度330℃,n(THF)/n(MA)=1.30,泵料速度33000mL/h,床内径1000mm,净床高3000mm,催化剂装填量2500kg,床层装填高1050mm,列管管径76mm,温度梯度T1-4=240-345℃,压力梯度P1-3=0.2-0.4-0.01MPa,一次合成粗品含量即达97%,采用共沸精馏技术,产品纯度≥99.5%,水分<0.1%,总收率≥97.5%,质量优于国外试剂的水平,催化剂长期使用无需再生,稳定性好。

The preparation of 1-methylpyrrolidine under the condition of effective catalyst γ-Al2O3 for catalytic synthesis by dehydration of tetrohydrofuran with methylamine. Yield 97.5%, purity≥99.5%, moisture 0.1% was achieved on the optimized 200t/y producing process conditions: reaction temperature 330℃, methylamine(MA)/tetrohydrofuran(THF) (molar ratio): 1.30, speed of injecting raw materials: 33000mL/h, stop time: 15s. Purity of first crude product from the self-made fixed-bed reactor: 97.5%, temperature gradient: T1-4=240-345℃, presure gradient: P1-3=0.2-0.4-0.01MPa. The catalyst has high catalytic activities and rate, good chemical stability and little waste discharge in 10 years' synthesis.