固定床催化合成N-甲基哌嗪

采用浸渍法制备负载型Cu-Ni/Al2O3,Cu-Ni-Mo/Al2O3,Cu-Ni-Co/Al2O3,Cu-Ni-Cr/Al2O3,Cu/Al2O3催化剂,并用于催化以哌嗪和甲醇为原料的N-甲基化反应合成N-甲基哌嗪。在固定床中考察了不同负载型金属催化剂、反应温度、n(甲醇)∶n(哌嗪)、LHSV等因素对合成N-甲基哌嗪反应的影响。实验结果表明,Cu-Ni-Mo/Al2O3催化剂的催化活性最好;采用Cu-Ni-Mo/Al2O3催化剂,合成N-甲基哌嗪的适宜条件为:n(甲醇)∶n(哌嗪)=2.5,氢气为载气,LHSV=0.20h-1,反应温度180℃,反应压力0.8MPa;在此条件下,哌嗪的转化率达到90.5%,N-甲基哌嗪的选择性达到86.9%。

Catalytic Synthesis of N-Methyl-Piperazine in Fixed Bad Reactor

Supported catalysts,such as Cu-Ni/Al2O3,Cu-Ni-Mo/Al2O3,Cu-Ni-Co/Al2O3,Cu-Ni-Cr/Al2O3 and Cu/Al2O3,for synthesis of N-methyl-piperazine from piperazine and methanol were prepared through impregnation method.Effects of active component,reaction temperature,n(methanol)∶n(piperazine)and LHSV on the N-methylation were investigated in a fixed bed reactor.Activity of Cu-Ni-Mo/Al2O3 catalyst among the catalysts was the highest.Conversion of piperazine increased while selectivity to N-methyl-piperazine decreased with increases of both reaction temperature and n(methanol)∶n(piperazine).The conversion decreased while the selectivity increased with increase of LHSV.Under optimized reaction conditions:n(methanol)∶n(piperazine)2.5,hydrogen as supporting gas,LHSV 0.20 h-1,reaction temperature 180 ℃,reaction pressure 0.8 MPa and Cu-Ni-Mo/Al2O3 as catalyst,conversion of piperazine and selectivity to N-methyl-piperazine reached 90.5% and 86.9%,respectively.