456. Catalytic cracking of 1,3,5-triisopropylbenzene and low-density polyethylene over hierarchical Y zeolites and Al-SBA-15

Jim Kabenla Miezakyi Mensah, Penghui Yan, Aditya Rawal, Adam F. Lee, Karen Wilson, Neil Robinson, Michael Johns, Eric Kennedy, and Michael Stockenhuber, ChemCatChem (2023), DOI: 10.1002/cctc.202300884

Catalytic cracking of high molecular weight hydrocarbons underpins the production of fossil fuels from petroleum vapour and the recycling of polyolefin waste plastic. However, thermal cracking over conventional microporous solid acids is hindered by poor mass-transport. Here we explore the performance of hierarchical H-Y zeolites and Al-SBA-15 for the catalytic cracking of 1,3,5-triisopropylbenzene (1,3,5-TIPB) and low-density polyethylene (LDPE) in a continuous fixed-bed flow reactor. Single and multiple demetallation strategies (dealumination, desilication and/or acid washing) were used to create hierarchical mesoporosity in H-Y zeolite and modify the solid acidity. Physicochemical properties were studied by X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), gas adsorption, in-situ Fourier transform infrared (FTIR), and 29Si and 27Al nuclear magnetic resonance (NMR). Dealumination and sequential dealumination-desilication-acid washing promote the selective deep cracking of both feedstocks; HNO3 dealuminated H-Y produces six times more propene from 1,3-5-TIPB, and ~30% more benzene and xylenes from LDPE, than the parent H-Y.