Aromatisation of Furan over Phosphorous Modified ZSM-5

Abstract

The aromatisation of both 2-methylfuran and 2,5-dimethylfuran was studied over phosphorous modified HZSM-5. Presence of phosphorus modifies acidity and surface area of the zeolite. Advanced characterisation techniques such as FT-IR, 27Al, 29Si, 31P MAS, 2D 27Al MQMAS solid state NMR were used to elucidate the phosphorus – zeolite interactions. Using FT-IR and 27Al NMR, formation of AlPO species can be observed with increasing weight loading. Furthermore, 31P NMR revealed a wide range of free and condensed phosphorous compounds which were partly removed by washing, resulting in a significant improvement of acidity, and surface area. Introduction of phosphorus results in the decrease of side reactions during the aromatisation of both 2-methylfuran and 2,5-dimethylfuran. Thermogravimetric analyses revealed that lower coke was formed for the PHZSM-5 catalyst, and after washing and calcining, selectivity also improves considerably. Co-feeding ethylene further reduces side reactions, resulting in lower deactivation reaction rates, whilst increasing BTX yield.