High activity in catalytic cracking of large molecules over micro-mesoporous silicoaluminophosphate with controlled morphology

A novel micro-mesoporous silicoaluminophosphate (MUS-5) with controlled morphology has been first synthesized in a two-step route. The physical properties of the silicoaluminophosphate were characterized using XRD, SEM, TEM, nitrogen adsorption-desorption and NH3-TPD techniques. When the pH value of the solution system was varied in the range from 2.0 to 5.0, three different morphologies of silicoaluminophosphate including chain-like, flower-like and barrel-like morphology were obtained. Catalytic tests showed that the silicoaluminophosphate exhibited higher catalytic activity compared with the conventional microporous SAPO-5 under the same conditions for catalytic cracking of 1,3,5-triisopropylbenzene heavy aromatics. The remarkable catalytic reactivity was mainly attributed to the presence of the hierarchical porosity in the silicoaluminophosphate catalyst.