DME-to-hydrocarbon over an MFI zeolite: product selectivity controlled by oxygenates under the kinetic regime

The influence of process variables on the DME-to-hydrocarbon (DtH) conversion has been assessed. The reaction was studied at atmospheric pressure, over an MFI zeolite (H-ZSM-5, SiO₂/Al₂O₃ = 58), in a gradientless recycle reactor, under the kinetic regime, and process variables in the range of 598-648 K and space time in the range of 0.008-0.040 h kg_cat kg_DME ^-1. The results showed that DME and methanol are not in equilibrium, that the cis-/trans-C₄ olefins are in equilibrium with each other but not with the 1-butene, while C₅ ⁺ hydrocarbons are favored at high oxygenates conversion. Finally, it was observed for the first time, to best of the knowledge of the current authors, that under kinetically controlled conditions, the selectivity to main groups of products can be described by the oxygenates conversion (x_oxy), independently of the process conditions, which means that the x_oxy controls the process selectivity independently of reaction temperature and space time.