Transalkylation of Multi-secbutylbenzenes with Benzene over Hierarchical Beta Zeolite

A hierarchical beta zeolite synthesized by quasi-solid phase conversion method was characterized by BET, scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray diffraction (XRD), temperature-programmed desorption of ammonia (NH3-TPD), 27Al and 29Si magic angle spinning nuclear magnetic resonance (27Al and 29Si MAS NMR), and its catalytic performance was compared with that of conventional microporous beta zeolite for liquid phase transalkylation of multi-secbutylbenzenes (MSBBs) with benzene. The results indicate that the hierarchical beta zeolite consists of nanosized crystals with a meso/microporous structure and has stronger acid strength than the microporous beta zeolite. The higher conversion of tri-secbutylbenzene (TSBB) and selectivity of sec-butylbenzene (SBB) are achieved on hierarchical beta zeolite than microporous beta zeolite, while the conversion of di-secbutylbenzene (DSBB) is slightly higher. The improvement of catalytic performance over hierarchical beta zeolite can be ascribed to the presence of mesopores, nanosized crystals and stronger acidity.

The catalytic performance of the hierarchical beta zeolite prepared by quasi-solid phase conversion method was estimated for transalkylation of multi-secbutylbenzene (MSBB) with benzene and compared with that of microporus beta zeolite. The reaction results show that the higher conversion of MSBBs and higher sec-butylbenzene (SBB) selectivity are obtained on hierarchical beta zeolite than conventional microporous beta zeolite. The improvement of catalytic performance can mainly be attributed to the enhanced accessibility of catalytic active sites, lower diffusion barrier and strong acid strength, due to the presence of mesopores, nanosized crystals and strong acidity hierarchical beta zeolite. And the results imply that hierarchical beta zeolite may offer an opportunity for reactions in which both good mass transfer of bulky reactants and strong acidity are needed.Figure optionsDownload as PowerPoint slide