Catalytic dehydration of ethanol-to-ethylene over Rho zeolite under mild reaction conditions

Abstract A small-pore zeolite, Rho having 8-membered ring opening and 3-dimensional (3-D) channels is synthesized via a greener process, without the use of a structure-directing agent. The zeolite Rho is crystallized by a conventional hydrothermal reaction under static conditions. XRD pattern showed phase purity of RHO-type crystalline topology, and SEM images depicted polyhedral particles with bimodal size distribution. The average size of small and large sized particles are 200 nm and 1000 nm, respectively. The amount of total solid-acid sites on Rho zeolite is 2.534 mmol g −1 and BET specific surface area reached to 812 m 2  g −1 . The zeolite is tested for a gas-phase conversion of ethanol-to-ethylene in the temperature range of 200–400 °C. The catalytic efficiency and stability of Rho zeolite are compared with the materials extensively used in the dehydration of alcohols; a control zeolite (ZSM-5) and three different samples of γ-Al 2 O 3 . For ethanol dehydration under mild reaction conditions, the overall catalytic efficiency of Rho is superior to that of the ZSM-5 zeolite and the γ-Al 2 O 3 materials. The strength and concentration of solid-acid sites are the main driving factors in the low-temperature dehydration of ethanol-to-ethylene.