Synthesis Of Piperazine And Triethylenediamine From Ethylenediamine Catalyzed By Modified HZSM-5

Triethylenediamine and piperazine were chemical raw material and pharmaceutical intermediates respectively. At present, with the improvement of the technology in piperazine synthesis, the profits of piperazine have became more and more dwindling. Many manufactures were trying to synthesize triethylenediamine from piperazine. In this paper, triethylenediamine was synthesized with HZSM-5 zeolite modified by ion exchanging with K+.1. The thermodynamics of the system that synthesizing triethylenediamine and piperazine from ethylenediamine was analyzed to guide the experiment with theory. Through the thermodynamic calculation, the relationship of reaction enthalpy, Gibbs Free Energy and equilibrium constant of the main and side reactions with the temperature were gotten, then the feasibility and problems being paid attention of the experiments were gained either.2. The HZSM-5 zeolite had the ability of shape selection because it has preferable channel structures and ability of ion exchanging because of the imbalance of the cationic on its surface. The key influences of ion exchange with high temperature were optimized by single factor experiment. The result was:the concentration of KCl was 1.Omol/L, the time of ion exchange was 5h, the temperature of ion exchange was 70?.3. The result of synthesis of triethylenediamine from ethylenediamine was brilliant. The reaction conditions were optimized by single factor experiment. The best reaction conditions were:the type of catalyst packing mode was upper loading, the residence time was 88.06min, the reaction temperature was 340?, the concentration of ethylenediamine was 5.90mol/L. In the catalyst stability experiment within 36h, the catalyst achieved good stability. The tranformation percentage of ethylenediamine was maintained about 85%, the selectivity of triethylenediamine maintained was about 51% and the piperazine was maintained about 21%.4. Finally, the catalysts modified before and after raction were characterized using SEM, EDS, XRD, Pyridine-IR, NH3-TPD.et al. The HZSM-5, KCl-ZSM-5, KZSM-5 were characterized by EDS and XRD. The characterized result was found that there was not KCl crystal in the KZSM-5. Through the characterization of Py-IR and NH3-TPD was found that the B acid site disappeared and the L acid site became enriched, at the same time the strong acid sites disappeared. The catalytic mechanism was discussed by analyzing the size of ZSM-5's pore and bond parameters of reaction molecules.