Research On Catalytic Synthesis Of Piperazine And Triethylenediamine On Zeolite

The piperazine and triethylenediamine act as the important pharmaceutical intermediates and raw materials in fine chemical synthesis bear an important role in the chemical industry. In recent years, the demand for both increases every year, but the relatively backward technology is difficult to meet the current demand. Therefore, study on the high efficiency catalyst has a very important significance. This article mainly research on the modified zeolite with the high coversion and high selectivity.Firstly, to choose the best carrier to modify among the zeolite of H-ZSM-5with different Si/Al、β、USY、NaY、MCM22, andγ-Al2O3MgO, neutral activated alumina. Then choose the H-ZSM-5(Si/Al=38) as the best carrier. After the research on different modified methods,modified conditions and different single feed. Ultimately determine the excess impregnation with metal nitrates as the best modified methods, the optimum modification conditions is stirring at60℃for8hours with a reflux condenser, the preferable single reaction materials is ethanolamine. Use the the excess impregnation method to modify on the H-ZSM-5(Si/Al=38). After the catalytic performance evaluation of different types of metal nitrate with different loaded amount,determine the ZSM-5loaded with4%Sr(NO3)2and4%Zr(NO3)4·5H2O as the best modified catalysts. Then set the ZSM-5loaded with4%Sr(NO3)2as the best zeolite to study on the reaction conditions.Evaluate the process conditions with the catalyst of ZSM-5loaded with4%Sr(NO3)2. Determine the optimal reaction conditions for the temperature of380℃, the WHSV for0.5h-1, and react at atmospheric pressure.After different characterization methods of XRD, NH3-TPD, SEM, HRTEM, found that the modified metal is more evenly distributed in the catalyst, the relative degree of crystallinity change a little, the specific surface area of the catalyst is not significantly affected the reaction result. And found that the strength of the weak acid in the catalyst is the main factor affects the experiment result.Finally, test the modified catalyst life under the optimum condition The modified catalyst can maintain a high activity within72h Ethanolamine conversion can reach90%or more. the total yield can reach above75%. Compared to the unmodified vector, the conversion of the feedstock, the total yield of the product are improved by more than30%. Moreover, the modified catalyst life is significantly better than the unmodified carrier. Then study on the regenerated catalyst, found that the regenerated catalyst still has good catalytic activity and can be reused while compared with the new catalyst under the same reacting condition.