Physicochemical Properties and Catalytic Performance of a Novel Aluminosilicate Composite Zeolite for Hydrocarbon Cracking Reaction

A novel micro-micro/mesoporous aluminosilicate ZSM-5-Y/MCM-41 composite molecular sieve with a MCM-41 type structure was synthesized through a novel process of the self-assembly of CTAB surfactant micellae with silica-alumina source originated from alkaline treatment of ZSM-5 zeolite. The physical properties of the ZSM-5- Y/MCM-41 composite molecular sieve were characterized by XRD, Py-FTIR and N2 adsorption-desorption techniques. Different kinds of molecular sieves including ZSM-5, Y zeolite, AI-MCM-41, ZSM-5/MCM-41 and ZSM-5-Y/MCM- 41 as cracking catalysts were investigated, using 1,3,5-triisopropylbenzene （1,3,5-TIPB） as the probe molecule. Catalytic tests showed that the ZSM-5-Y/MCM-41 composite molecular sieve exhibited higher catalytic activity compared with the microporous ZSM-5 zeolite, Y zeolite, mesoporous A1-MCM-41 molecular sieve and ZSM-5/MCM-41 composite molecular sieve under the same conditions. The remarkable catalytic activity was mainly attributed to the presence of the hierarchical pore structure and proper acidity in the ZSM-5-Y/MCM-41 composite catalyst. Meanwhile, a carbcnium ion mechanism was put forward for the cracking of 1,3,5-TIPB.

Hydrothermal Synthesis and Mechanism for Formation of Novel Micro-Micro-Mesoporous Aluminosilicate Composite Zeolite

A novel micro-micro-mesoporous aluminosilicate LS-BFMZ （low-silica-BEA（beta）-faujasite （Y）-mesoporous） composite zeolite with the MCM-41 type structure was synthesized through a novel process involving the self- assembly of CTAB surfactant micellae with silica-alumina source originated from alkaline treatment of the beta zeolite. The physical properties of the LS-BFMZ composite zeolite were characterized using various techniques, including XRD, IR and SEM techniques. Meanwhile, a possible mechanism regarding the formation of the LS-BFMZ composite zeolite was proposed.

Study on Synthesis and Catalytic Performance of Hierarchical Zeolite

A kind of hierarchical zeolite catalyst was synthesized by hydrothermal method. X-ray diffraction （XRD） and nitrogen adsorption-desorption method were used to study the phase and aperture structure o（ the prepared catalyst. Infrared （IR） spectra of pyridine adsorbed on the sample showed that the hierarchical zeolite really had much more Bronsted and Lewis acidic sites than the HZSM-5 zeolite. The catalytic cracking of large hydrocarbon molecules showed that the hierarchical zeolite had a higher catalytic activity than the HZSM-5 zeolite.

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.