Olefin methylation over iron zeolites and the methanol to hydrocarbons reaction

The effect of olefin addition to a stream dimethyl ether on the methanol homologation reaction is investigated using iron-substituted zeolites Fe-beta and Fe-ZSM-5. was plug-flow microreactors in temperature range 240–400 °C, at total pressure 0.239 MPa WHSV 6.12 (g DME/g cat -hr). For (Si/Fe= 9.2) catalysts, isobutene co-feeding almost doubles (DME) consumption rate shifts selectivity towards larger olefins with carbon numbers from 5 7. Addition above 6.3%, however, resulted reduction DME rates, an assigned replacement surface methoxy groups for adsorbed zeolite pores. Below 340 °C hydride-transfer rates are negligible; stable over 5.5 h products consist exclusively small amount methane. Above 360 onset catalytic hydride transfer processes observed leading fast catalyst deactivation increase concentration aromatic species. Iron ZSM-5 (Si/Fe = 21.4) catalysts under similar conditions consumes faster than approximately three times TOF (on per iron basis). Fe-ZSM-5 selective distribution (C5 C8) as compared which primarily C5 C7. Co-feeding (2-methyl-2-butene, 2,3-dimethyl-2-butene, 2,3,3-trimethyl-1-butene, 2,4,4-trimethyl-2-pentene) 3.9% changed cracking (C4 compounds such isobutene). As size increases, also observed. These results show that Fe-zeolites promising route methylation relatively low temperatures producing branched product highly dependent pore structure olefin.