On the reaction mechanism for propene formation in the MTO reaction over SAPO-34

Three different feeds: methanol, methanol/ethanol/water (2 ∶ 1 ∶ 1 molar ratio) and13C-methanol/ethanol/water (2 ∶ 1 ∶ 1) have been converted to hydrocarbons over a SAPO-34 catalyst at 420 °C using argon carrier gas. The products were analyzed by GC-MS allowing the determination of the isotopic composition of the reaction products. The experiments show that the majority of the propene molecules are formed directly from methanol, and that only a minor part is formed by methylation of ethene.