A novel co-production process for piperazine and its N-monoalkyl derivatives

Abstract

A novel co-production process for piperazine and its N-monoalkyl derivatives has been established. N-b-hydroxyethyl-1,2-ethylenediamine and alcohols were used as the starting materials and the process was carried out over Cu-CrLa/c-Al 2 O 3 in a fixed-bed reactor. Alcohols acted not only as the solvent but also as the alkylating reagent. The catalyst was characterized by XRD, XPS and BET. The results obtained showed that Cu 0 particles in the catalyst were the active sites and doping with La led to enhancement of catalyst activity. Process conditions including reaction temperature, hydrogen pressure, and molar ratio of the reagents were optimized and the distribution of the products was found to be markedly dependent on reaction temperature. Using optimum conditions, piperazine and its N-monoalkyl derivatives were obtained with satisfactory yields and distributions. The catalyst performed well for over 300 h.