由N-羟乙基乙二胺合成哌嗪

研究了以N－羟乙基乙二胺（HDEA）为原料，经催化脱水环化全盛哌嗪（PIP）的过程；考察了不同的催化剂，催化剂用量，反应时间、温度、压力，溶剂配比等对转化率和哌唪选择性的影响。结果表明，较好的催化剂为Raney Ni(C)，在180℃，3MPa，溶剂与原粒配比6：1（mol:mol），催化剂用量ω=0.10，反应时间3h时，得到的转化率为89.2％，选择性85.0％，收率75.8％。小试数据能在放大试验中重复，精馏分离得到的产品哌嗪纯度＞98.0％。

Synthesis of Piperazine from N-Hydroxyethylethylenediamine

A catalytic dehydrolysis process for synthesis of piperazine (PIP) from N-hydroxyethylethylenediamine (HDEA) has been studied. Various kinds of catalysts, such as acid catalysts, metal oxide supported on γ-Al2O3 and Raney Ni have shown certain activities on this reaction. In this case, the suitable catalyst is Raney Ni, especially the Raney Ni (C) which is prepared by adding some copper. The effect of content of metal copper on the reaction results has also been observed, it shows that the optinum wCu is 0.07～0.10. The optimal reaction conditions for Raney Ni (C) are 180°C， 3MPa, H2O∶HDEA=6∶1(mol∶mol), catalyst amount wcat=0.10 and reaction time 3h. Under these conditions the conversion and selectivity are 89.2% and 75.8% respectively. The results of scale-up experiment are comparable to these of the laboratory test. The SEM micrographs of fresh and used catalyst showed that the used catalyst has been covered by some substance, and the skeleton structure can not be distinguished clearly. So the conversion and selectivity of the product decrease with the used times. After fractional distillation, the purity of the product PIP is higher than 95%.