Method for preparing piperazine and triethylene-diamine

The invention discloses a method for preparing piperazine and triethylene-diamine. The method comprises the following steps: (1) leading ethylene diamine to be reacted under the catalysis of a first modified zeolite-loaded Pd catalyst, to obtain a first reaction liquid; and (2) leading the first reaction liquid to be reacted under the catalysis of a second modified zeolite-loaded Pd catalyst, to obtain a reaction liquid containing piperazine and triethylene diamine. By adopting the method, pyrazine derivatives cannot be generated during reaction, so that the economic and environment-friendly purposes are achieved; the raw materials for reaction are cheap and easily available, the conversion rate is high, the selectivity of products is good, the byproducts are fewer, the production cost is low, and the production composition of piperazine and triethylene diamine can be adjusted by changing reaction conditions according to the market demand condition of the products, and the method is suitable for industrial large-scale production.