Microwave-assisted rapid synthesis of nanosized SSZ-13 zeolites for effective conversion of ethylene to propylene

SSZ-13 is an attractive zeolite with chabazite topology composed of small pores with 8-membered rings. In this work, we report a highly effective method to synthesize SSZ-13s with microwave (MW) heating. Compared with conventional electric (CE) heating, MW heating accelerates both the nucleation and crystal growth rates of the synthesis by 6 and 18 times, respectively. Importantly, MW-assisted rapid synthesis produces the SSZ-13 with the smallest particles (<50 nm). However, the CE-assisted synthesis produces large/inhomogeneous particles (size: 0.4–1 μm). The obtained SSZ-13s were employed in acid catalysis or ethylene-to-propylene (ETP) reactions. The record-small SSZ-13s were more efficient in the ETP reactions, with more stable ethylene conversion/propylene yield (at the same time on stream) and higher propylene selectivity (at the same ethylene conversion), than large SSZ-13s. Finally, the maximum propylene yield (62%) is competitive or better than any SSZ-13s obtained via direct synthesis from precursors like silica and alumina.