Alkali Metal Ion-Exchanged Zeolite X from Bamboo Leaf Biomass as Base Catalysts in Cyanoethylation of Methanol Enhanced by Non-Microwave Instant Heating

Abstract

A series of alkali form (Na, K, Cs, and Ca) faujisite X-type zeolites were prepared from bamboo leaf ash, which was derived from bamboo agricultural waste. The XRD and SEM results revealed that the zeolite structure remained intact after ion exchange treatment. A very high degree of ion exchange (≥ 85 %) was achieved in all of the prepared zeolite samples. The zeolite samples were tested in a solvent-free cyanoethylation reaction of methanol under an instant heating environment that mimicked microwave fast heating, which was explored for the first time. The catalytic performances of the zeolite samples were well correlated with their surface basicity, which was characterised by pyrrole adsorption followed by in situ infrared spectroscopy. The CsX zeolite showed excellent catalytic performance (~97 % reactant conversion and 100 % product selectivity within 15 min), which was comparable to the microwave-assisted system and superior to the normal reflux system. The catalytic activity of the CsX zeolite was retained even after 10 cycles of reaction.