Synthesis of MgAPO-11 Molecular Sieves and the Catalytic Performance of Pt/MgAPO-11 for n-Dodecane Hydroisomerization

A series of MgAPO-11 molecular sieves have been synthesized by varying the crystallization time, the P/Al molar ratio, and the Mg source. X-ray diffraction, X-ray fluorescence spectroscopy, and temperature-programmed desorption of NH3 have been used to characterize the crystalline phase, the Mg content, and the acidity of MgAPO-11, respectively. The results show that the synthesis conditions have an effect on the crystalline phase, the Mg content, the acidity, and thereby the catalytic performance of Pt/MgAPO-11 in the hydroisomerization of n-dodecane. The reaction data reveal that the activity of Pt/MgAPO-11 is dependent on the number of strong acid sites of MgAPO-11. Short crystallization time, P/Al molar ratio of 1.0, and Mg(NO3)2 as the Mg source favor the increase in the number of the strong acid sites of MgAPO-11 and hence promote the catalytic activity of Pt/MgAPO-11 for the hydroisomerization of n-dodecane.