Study On The Catalyst Pd/NaY For The Synthesis Of Diethyl Carbonate From Carbon Monoxide And Ethyl Nitrite

Diethyl carbonate (DEC) is one of the important green chemicals and is widely used as an important intermediate various organic syntheses. It was found recently that DEC could act for as a kind of oxygenous additive in oil to replace traditional additive methyl tert-butyl (MTBE). In this paper, supported Pd/NaY catalysts for the synthesis of DEC by CO vapor phase at low-pressure were studied.The effect of supporter from different producers on the catalytic activity of Pd/NaY was studied and the results show that the supporter from Lanzhou Petrochem Company is better than others. For Pd/NaY catalyst, compression molding method is better in reducing the effect on the catalytic activity than strip mill molding method. For Pd/NaY catalyst, the suitable calcinations condition is to heat it by 0.5K/min to 200oC and then keep two hours. In the preparation process of catalyst by ion-exchange method, the acidity of the catalyst was low which can prevent side reaction at low ammonia concentration of 0.14%.The influence of various additives on the catalytic performance is studied. The result show that the selectivity and activity can be improved significantly by adding Ce(NO3)2. The modification of Pd/NaY by H2C2O4,(NH4)2 HPO4 improved the selectivity through removing aluminium framework and reduce the acidity. The STY (Space-time Yield) of DEC increased from 98.5g/(lcat·h) to 128.6g/(lcat·h). The FT-IR,XRD and Porous structure figures indicated that the above modification did not change the crystal structure of the zeolite. Py-IR and NH3-TPD showed that modification could change the type of acid and reduce the acid concentration and intensity.The mechanism of coke formation and regeneration is discussed. The deactivation and regeneration process followed three dimensioned diffusion mechanism coincidence with Jander equation. The kinetic function was Kissinger function.