In situ synchrotron x-ray powder diffraction studies of crystallization of microporous aluminophosphates and Me2+-substituted aluminophosphates

in situ synchrotron X-ray powder diffraction was used to study the crystallization of microporous aluminophosphate and of Mg2+-, Mn2+-, Co2+-, and Zn2+-substituted aluminophosphates. The gels contained the templates 2-(diethylamino)ethanol, di-n-propylamine, triethylamine, and tripropylamine and were heated in quartz glass capillaries at temperatures up to 200 degrees C, The main crystalline reaction products formed were AlPO4 (tridymite type), APO-5 (AFI), APO-11(AEL), MgAPO-5 (AFI), MnAPO-5 (AFI), CoAPO-5 (AFI), ZnAPO-39 (ATN), and ZnAPO-47 (CHA). A kinetic analysis of the crystallization of MnAPO-5 (AFI) and ZnAPO-47 (CHA) was performed using isothermal in situ synchrotron X-ray powder diffraction data. The apparent activation energies for the hydrothermal nucleation of MnAPO-5 (AFI) and ZnAPO-47 (CHA) were 161(6) and 112(3) KJ/mol, respectively. The crystallization of MnAPO-5 could be modeled using a first-order expression giving an apparent activation energy of the crystal growth of 81(6) kJ/mol. The crystallization of ZnAPO-47 was more complex, and the crystallization curves could not be described using simple kinetic expressions.