SYNTHESIS AND CATALYTIC PERFORMANCE OF ITQ-24 ZEOLITE

Abstract

Abstract: ITQ-24 zeolite was synthesized using 1,1’-[1,4-phenylenebis（methylene）] bis [1-methyl pyrrolidinium] hydroxide as organic structure-directing agent（OSDA）. The effects of Ge content，OSDA amount，HF content，crystallization temperature，and stirring speed on the crystallization of ITQ-24 zeolite were investigated,respectively. X-ray diffraction（XRD），scanning electron microscope（SEM），temperature-programmed desorption of NH₃（NH₃-TPD）and Fourier transform infrared spectroscopy of pyridine adsorption（Py-IR）methods were carried out to characterize the obtained zeolites. The suitable molar compositionn（SiO₂）∶n（GeO₂）∶n（OSDA）∶n（H₂O）for the crystallization of ITQ-24 zeolite is 1∶（0.2-0.5）∶0.3∶（5-20），and the optimum temperature is 170 ℃ under dynamic condition. The ITQ-24 zeolite has high hydrothermal stability and contains lots of weak and Lewis acid sites. In the oxidation reaction of cyclohexanone to ε-caprolactone，using ITQ-24 as catalyst,the ε-caprolactone selectivity reached 54.5% with 22.5% cyclohexanone conversion under the optimum temperature of 80 ℃.

Key words: ITQ-24, zeolite, Baeyer-Villiger oxidation, cyclohexanone, ε-caprolactone

References

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